MASARYK UNIVERSITY
FACULTY OF MEDICINE
Modern approaches in diagnostics of inflammatory
bowel disease in a pediatric population
HABILITATION THESIS
In Pediatrics
(Collection of previously published scholarly works)
Brno 2021 Petr Jabandžiev, MD, Ph.D.
2
I hereby declare that I wrote this habilitation thesis on my own, using the relevant resources
listed in the references.
..........................
Signature
3
Acknowledgment
I would like to thank very sincerely all my mentors who stimulated my interest in research
questions, namely Prof. Ondřej Slabý and Prof. Ajay Goel.
Many thanks are due to my research collaborators and colleagues from the Department of
Pediatrics, University Hospital Brno; Faculty of Medicine, Masaryk University; and Central
European Institute of Technology.
Last but not least, I would like to express my sincere thanks to my whole family, my always
supportive wife Hana, and our beloved children.
4
Commentary
Inflammatory bowel disease (IBD) is an umbrella term describing disorders that cause chronic
inflammation of the gastrointestinal tract. IBD affects both children and adults, but children
have their specificities. IBD is classically divided into Crohn’s disease and ulcerative colitis.
In the current view, pediatric IBD encompasses a continuum of clinical categories, including
typical ulcerative colitis, atypical ulcerative colitis, Crohn’s colitis, and Crohn’s disease.
Where none of the above can be determined, we refer to inflammatory bowel disease
unclassified. The incidence of IBD has been increasing in recent decades worldwide, and IBD
has moved from being previously at the periphery of interest among gastroenterologists into
focus as one of the most studied diseases. The pathogenesis of IBD involves an interaction of
genetic and environmental variables that disrupt the relationship between the immune system
and the gut microbiota. The clinical manifestations of IBD can be not only intestinal but also
extraintestinal, and more aggressive forms of the disease are often present in children
compared to adults. The course of IBD is unpredictable, with alternating periods of flare-up
and remission. IBD in childhood can disrupt somatic and psychological development and has
relevant social and economic consequences. Therefore, accurate and timely diagnosis and
adequate therapy are essential. The presented habilitation thesis documents the author’s
experience in managing pediatric patients with various gastroenterological problems, but at its
core is a focus on IBD and description of modern diagnostic approaches. This habilitation
thesis is conceived as a collection of 10 articles previously published by the author and his
colleagues. It contains individual chapters dealing with the basic aspects of IBD. Where
relevant, it is followed by commentaries introducing the topic of each publication, describing
the current state of knowledge and how the author has contributed to knowledge in this field.
The work is based on research activities at the authors’ workplaces, the Department of
Pediatrics, University Hospital Brno; the Faculty of Medicine, Masaryk University; and
Central European Institute of Technology.
5
Content of the work
Acknowledgment ....................................................................................................................... 3
Commentary............................................................................................................................... 4
1. Introduction ............................................................................................................................ 7
2. Classification.......................................................................................................................... 9
2.1. Types of IBD ................................................................................................................... 9
2.2. Disease location............................................................................................................... 9
2.3. Age of onset................................................................................................................... 11
2.4. Authors’ contribution to the knowledge........................................................................ 11
3. Epidemiology ....................................................................................................................... 14
3.1. Authors’ contribution to the knowledge........................................................................ 15
4. Etiopathogenesis................................................................................................................... 17
4.1. Intestinal barrier and immune response......................................................................... 18
4.2. Environment .................................................................................................................. 18
4.3. Genetics ......................................................................................................................... 19
4.4. Authors’ contribution to the knowledge........................................................................ 19
5. Diagnostics........................................................................................................................... 22
5.1. Patient’s history, symptoms, and clinical examination ................................................. 23
5.2. Laboratory tests ............................................................................................................. 23
5.3. Endoscopic examination................................................................................................ 24
5.4. Histomorphologic examination ..................................................................................... 25
5.5. Imaging methods ........................................................................................................... 25
5.6. Examples of modern diagnostic methods potentially useful in clinical practice........... 25
5.7. Authors’ contribution to the knowledge........................................................................ 27
6. Differential diagnostics ........................................................................................................ 30
6.1. Very-early-onset IBD .................................................................................................... 31
6.2. Authors’ contribution to the knowledge........................................................................ 33
7. Therapy................................................................................................................................. 38
7.1. Medical therapy ............................................................................................................. 38
7.2. Nutritional therapy......................................................................................................... 40
7.3. Endoscopic and surgical therapy ................................................................................... 40
7.4. Authors’ contribution to the knowledge........................................................................ 40
8. Complications....................................................................................................................... 42
8.1. Complications from within the gastrointestinal tract .................................................... 42
6
8.2. Extraintestinal and systemic complications................................................................... 43
8.3. Authors’ contribution to the knowledge........................................................................ 43
9. Potential perspectives on further research............................................................................ 45
9.1. General perspectives on research in the field of IBD.................................................... 45
9.2. Author’s perspectives on research in the field of IBD .................................................. 46
10. Conclusions ........................................................................................................................ 52
List of abbreviations................................................................................................................. 53
List of Figures .......................................................................................................................... 55
List of Tables............................................................................................................................ 56
References ................................................................................................................................ 57
List of Annexes ........................................................................................................................ 80
7
1. Introduction
Inflammatory bowel disease (IBD) is a term encompassing a range of chronic inflammatory
conditions affecting the gastrointestinal tract and is traditionally subdivided into Crohn’s
disease (CD) and ulcerative colitis (UC).1
CD is an inflammatory disease affecting any part of
the gastrointestinal tract from the oral cavity to the rectum, but the most typical site of
involvement is the terminal ileum. Clinical manifestations of CD in children are varied and
may include fatigue, weight loss, abdominal pain, diarrhea, growth impairment, and delayed
puberty.2
UC is characterized by inflammatory involvement of the colon. Typical symptoms
depend on the extent of the disease and include crampy abdominal pain and diarrhea, often
with blood.3
According to various sources, up to one-quarter of patients with IBD are
diagnosed in childhood or adolescence.4, 5
The incidence of IBD has been increasing in recent
decades in all populations (pediatric and adult) and worldwide.6, 7
The causes of this
phenomenon are not clearly understood and this is probably one of the reasons why IBD has
moved from the periphery of interest among gastroenterologists to one of the most studied
diseases.8
The pathogenesis of IBD involves an interaction of genetic and environmental
variables that disrupt the relationship between the immune system and the gut microbiota.9
There are significant differences between the child and adult populations, and patients
diagnosed during childhood have differential characteristics (e.g., higher prevalence of CD,
more extensive disease, and more frequent family history).10-13
In addition, the use of
immunomodulators and biologic agents is greater in childhood‐onset patients, suggesting a
more aggressive course of the disease.14
The course of IBD is unpredictable, with alternating
periods of flare-up and remission. The variety of symptoms, both intestinal and
extraintestinal; the presence of complications; often challenging diagnostic procedures; and
the therapy itself, including potential side effects, make the disease challenging for young
patients and their families. Proper somatic development may be impaired, while quality of
life, social life, and education also are affected.15
The main elements of diagnostic workup
include upper and lower endoscopy with mucosal biopsies and imaging procedures, and, in
the differential diagnosis, it is necessary to exclude many IBD-mimicking diseases.16
Accurate and timely diagnosis and adequate therapy are essential, because diagnostic delay is
associated with complicated disease course.17, 18
Therapeutic options include medication,
nutritional therapy, and surgery.19-22
The goal of IBD treatment is achieving deep remission of
the disease, which means elimination of the patient’s symptoms, normalization of laboratory
parameters, induction of mucosal healing, restoration of normal growth, and prevention of
8
surgical complications.23
Thus, an interdisciplinary approach involving different health
professions is essential in the management of patients with such complex medical problems.24
Moreover, the professionals caring for these patients must have a broad understanding of the
topic because there is increasing interest in such additional treatment modalities as
complementary and alternative medicine.25-27
9
2. Classification
2.1. Types of IBD
Even though IBD in children and adults is similar in many ways, pediatric IBD (PIBD) often
has atypical features making classification of PIBD challenging.11, 28, 29
Moreover, accurate
phenotype classification of IBD is crucial for appropriate management and prognostication.30
Consensus-based criteria for the diagnosis of PIBD were published in 2005.31
These included
a defined diagnostic work-up for new PIBD patient that enabled standardized diagnostics for
CD, UC, and indeterminate colitis.31
This was an important achievement for both clinical
practice and clinical research. In 2014, the revised Porto criteria were released and identified
subtypes of PIBD as UC, atypical UC (atypical phenotypes such as macroscopic rectal
sparing, isolated non-serpiginous gastric ulcers, normal crypt architecture, absence of
chronicity in biopsies, or a cecal patch.), IBD unclassified (IBDU; inflammation is limited to
the colon with features that make differentiation between UC and CD uncertain even after a
complete workup), and CD.16
Consequently, the Paediatric IBD Porto Group of the European
Society of Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) published the
‘‘PIBD-Classes’’ criteria that standardized the differentiation of PIBD into five categories:
typical UC, atypical UC, IBDU, Crohn’s colitis, and CD.32
2.2. Disease location
The previously used Montreal classification for disease characterization had several
weaknesses regarding the classification of children.33, 34
For this reason, an international group
of pediatric IBD experts developed evidence-based consensus recommendations for a
pediatric modification of the Montreal classification (the so-called Paris classification) in an
effort to facilitate research in PIBD and create uniform standards for defining IBD
phenotypes.35
Table 1 and Table 2 summarize Paris classification for CD and UC,
respectively.35
10
Table 1. Paris classification for Crohn’s disease.
Age at diagnosis
A1a: 0–<10 years
A1b: 10–<17 years
A2: 17–40 years
A3: >40 years
Location
L1: distal 1/3 ileum ± limited cecal
disease
L2: colonic
L3: ileocolonic
L4a: upper disease proximal to ligament
of Treitz 
L4b: upper disease distal to ligament of
Treitz and proximal to distal 1/3 ileum
Behavior
B1: nonstricturing
nonpenetrating
B2: stricturing
B3: penetrating
B2B3: both penetrating and stricturing
disease, either at the same or different
times
p: perianal disease modifier
Growth
G0: no evidence of growth delay
G1: growth delay
Table 2. Paris classification for ulcerative colitis.
Extent
E1: ulcerative proctitis
E2: left-sided UC (distal to splenic flexure)
E3: extensive (hepatic flexure distally)
E4: pancolitis (proximal to hepatic flexure)
Severity
S0: never severe
S1: ever severe
It should be added that this classification has more use in research than in clinical practice.
Nevertheless, the Paris classification for PIBD could, for example, have a predictive value for
long-term worse outcome.36
11
2.3. Age of onset
PIBD patients can also be classified in terms of age. Montreal classification distinguished
pediatric-onset IBD as cases diagnosed before 17 years of age and labeled them A1.33
In the
Paris classification,35
A1 was further divided into A1a (diagnosed before 10 years of age) and
A1b (diagnosed between 10 and 17 years of age). Among A1a cases, those diagnosed before 6
years of age are classified as very-early-onset IBD (VEO-IBD).37
Furthermore, IBD cases
with onset by 2 years of age were classified as infantile-IBD and by 28 days of age as
neonatal-onset IBDs, respectively.37, 38
Now, therefore, we have subgroups of pediatric-onset
IBD (<17 years), early-onset IBD (<10 years), VEO-IBD (<6 years), infantile-onset IBD (<2
years), and neonatal-onset IBD (<28 days).37-39
IBD generally is regarded as a polygenic disease, and a genome-wide association study has
revealed more than 240 known disease-associated genes.40
Pediatric-onset IBD seems to have
a greater genetic component compared to adult-onset IBD due to lower cumulative exposure
to environmental factors.41
In pediatrics, the name IBD is also used for a group of diseases
that have similar symptomatology but are caused by rare genetic defects. Other diseases that
involve the symptoms of IBD have a separate name, often based on molecular classification,
and their manifestations are referred to as “IBD-like.”38, 39
Rare monogenic IBD and IBD-like
syndromes therefore present the genetic extreme where a single highly pathogenic variant
causes IBD symptoms. As such, pediatric-onset IBD represents a spectrum ranging from
extreme monogenic variants (typically VEO-IBD) to adolescent complex variants (as in
adults).41
Evaluating and managing children with VEO-IBD is a challenging field for pediatric
gastroenterologists worldwide.37, 42
Specifics in diagnostics of VEO-IBD will be further
described in another chapter.
2.4. Authors’ contribution to the knowledge
My colleagues and I described a unique diagnosis of trichohepatoenteric syndrome (THES)
(Annex 1). To our knowledge, this was the first case diagnosed in the Czech Republic. THES
can have a clinical presentation similar to that of VEO-IBD and is often assigned to this group
(or to VEO-IBD-like). The described patient had somatic retardation and woolly hair
appearance and suffered from recurring episodes of watery mucous diarrhea, impaired liver
functions, and failure to thrive (Figure 1).42
12
Figure 1. Clinical data of the patient with trichohepatoenteric syndrome.
(A) Overall habitus of the patient. (B) Detail of the hairy part of the head. Brittle, easily
breakable hair. (Ci) Hair analysis using light microscopy showing trichorrhexis nodosa.
Magnification 40×. (Cii) Bristly split hair ends. Magnification 40×. The figure had been
published in Jabandziev et al.42
Esophagogastroduodenoscopy and colonoscopy were performed at 4 years to rule out
possible IBD, but only signs of nonspecific colitis were evident. Massive parallel sequencing
13
targeting a panel of primary immunodeficiency-related genes was used to examine the
patient’s DNA. Next-generation sequencing (NGS) analysis revealed two heterozygous
variants in the TTC37 gene. Nonsense p.Arg1201* and missense p.Leu1505Ser variants in
exons 34 and 42, respectively, were evaluated as pathogenic based on in silico predictions,
their rare occurrence in the general population, and the fact that both mutations had already
been described in patients with THES. THES could be a life-threatening condition,
particularly in children who develop liver disease or severe infection courses, and it must be
considered in the differential diagnosis in children for whom a diagnosis of VEO-IBD is
being considered.42
14
3. Epidemiology
IBD has undoubtedly become a global disease.43, 44
Depending upon individual regions, we
can find regions with low, medium, and high incidences.7
Differences in incidence could also
be found by race45
and by age (children vs. adults).11
There is a general consensus within the
gastroenterologist community that the incidence of IBD is increasing worldwide,7, 44
and
especially in low-income countries.46, 47
With these trends, a significant burden on health
systems and economic impacts can be expected.48-50
It is not easy to compare and standardize
data from different parts of the world, however, due to heterogeneity among study designs.
Diagnostic criteria can differ. Some studies use hospital records, while others use surveys and
administrative data.51
The age limit is a vital inclusion criterion with a significant impact on
reported incidence rates, as individual studies differ significantly in their definitions of
childhood or upper age limit (15, 18, or 20 years respectively).6
Most data are retrospective;
only a few prospective population-based studies have been conducted, those being
particularly from developing countries. Furthermore, the incidence rates are often an
extrapolation from one or more regions of a country.51
It cannot be ruled out that better
diagnostics of IBD is at least partly responsible for the increase in incidence.52
In connection
with the differences in incidence in individual countries, a so-called north–south gradient is
discussed, with the highest incidence of IBD being found in the north.4
In adult patients, a
positive association with a country’s wealth (as measured by gross domestic product) has
been discussed.53, 54
It is also necessary to mention the fact that we do not have recent data
from a large number of countries, and most countries lack accurate estimates for the incidence
of pediatric IBD.51, 55
The most recent systematic review studying the incidence of IBD in the pediatric
population worldwide was published in 2018,6
and it is interesting to compare that with the
previous systematic review from 2011.4
The authors of the 2011 systematic review stated that
the incidence of CD was increasing especially in some countries and, conversely, that the
incidence of UC remained the same in most countries.4
In 2018, Sykora et al. reviewed 140
studies reporting data from 38 countries.6
The highest annual pediatric incidences of IBD
were 23/100,000 person-years in Europe; 15.2/100,000 in North America; and 11.4/100,000
in Asia, the Middle East, and Oceania. The highest annual incidences of CD were
13.9/100,000 in North America and 12.3/100,000 in Europe. The highest annual incidences of
UC were 15.0/100,000 in Europe and 10.6/100,000 in North America. The highest annual
incidences of IBD-U were 3.6/100,000 in Europe and 2.1/100,000 in North America. Overall,
15
67% of CD, 46% of UC, and 11% of IBD-U studies reported increasing incidence in the trend
analyses.6, 56
From a general perspective, it is not very clear how incidence trends will
continue to evolve. It is questionable whether, for example, developed countries are still
experiencing further increase in incidence. In a recently published systemic review and metaanalysis,
Roberts et al. stated that the incidence of pediatric IBD continues to increase
throughout Europe, with more robust evidence of a north–south than of an east–west
gradient.57
3.1. Authors’ contribution to the knowledge
Until recently, we did not have much information about the epidemiology of IBD in children
within the Czech Republic. The first Czech national survey was conducted and published by
Pozler et al. in 2006.58
This paper described how the incidence of CD had increased from
0.25/100,000 in 1990 to 1.25/100,000 in 2001. Schwarz et al.59
rather more recently (2017)
published a 16-year prospective study of pediatric IBD patients in the Pilsen Region of the
Czech Republic showing that a group of 170 pediatric patients (study period 2000–2015)
represented an average incidence of IBD per 100,000/year of 10.0 (6.2 for CD, 2.8 for UC,
and 1.0 for IBD-U).56, 59
Our study (Annex 2) aimed to determine the incidence and trends of IBD in the
population of Czech children.56
The study included a 16-year period in the South Moravian
Region. It characterized differences by sex and age and projected the incidence of IBD for
future years. Overall, 358 pediatric patients with newly diagnosed IBD at the Department of
Pediatrics, University Hospital Brno, were evaluated. Diagnosed were 192 children (53.6%)
with CD, 123 (34.4%) with UC, and 43 (12.0%) with IBD-U. The incidence of IBD increased
from 3.8 (CD 2.9, UC 0.9, and IBD-U 0.0) per 100,000/year in 2002 to 14.7 (CD 9.8, UC 4.0,
and IBD-U 0.9) per 100,000/year in 2017 (p<0.001) (Figure 2). The overall IBD incidence per
100,000/year was 9.8 (95% confidence interval [CI]: 8.8–10.9). Constituent incidences per
100,000/year were CD 5.2 (95% CI: 4.5–6.0), UC 3.4 (95% CI: 2.8–4.0), and IBD-U 1.2
(95% CI: 0.9–1.6). IBD incidence was projected to reach 18.9 per 100,000/year in 2022
(Figure 2). The incidence of CD, UC, and U-IBD found in our study, including the
proportions among them, were practically identical to the results from Schwarz et al.56, 59
Both
studies showed that the overall incidence of IBD is increasing in Czech children, and
especially the incidence of CD, while the trends for UC and IBD-U seem to be constant.
16
Despite some limitations, we would therefore suggest that our results are potentially similar to
the incidence to be found in pediatric IBD patients across the Czech Republic.56
Figure 2. Incidence rates per 100,000/year among children (0–18 years of age) newly
diagnosed with IBD (A) and CD (B) in South Moravian Region, 2002 to 2017 and 2018 to
2022.
Black points represent actual data. Broken blue lines indicate trend over the observed period
based on Poisson regression along with a 95% confidence interval. Blue points are future
projections. The figure had been published in Jabandziev et al.56
These results therefore suggest that incidence rates of pediatric IBD and its subtypes in the
Czech Republic are among the highest in the literature. Moreover, these data further
emphasize the need to identify risk factors that contribute to the increasing incidence of
IBD.56, 60
17
4. Etiopathogenesis
Knowing IBD’s pathogenesis is key to understanding the causes of IBD, and a better
understanding of these processes could lead to the development of novel IBD therapies.61
Despite significant achievements, we do not yet have a comprehensive theory describing all
the pathogenetic processes leading to IBD. There is growing evidence, however, that the
pathogenesis of IBD results from an interplay among host genetic susceptibility,
environmental factors, immunological abnormalities, and intestinal barrier alteration (Figure
3).62, 63
Figure 3. Mechanisms involved in the pathogenesis of inflammatory bowel disease.
Figure was prepared in accordance with Ramos et al.63
and created in collaboration with the
Service Center for E-Learning at Masaryk University, Faculty of Informatics.
18
4.1. Intestinal barrier and immune response
The mucosal barrier and its proper functioning, are essential in protecting against adhesion
and invasion of luminal microorganisms.64
This is made possible by intact epithelium,
synthesis of various antimicrobial peptides, and mucus layer formation.65
Damages to the
intestinal mucosal barrier include, among others, defective production of antimicrobial
peptides, changes in the thickness or composition of the intestinal mucus layer, changes in
pattern recognition receptors, and defects in the autophagy process.66
The intestinal
epithelium is in a functional equilibrium with the luminal contents. Disturbance of this
equilibrium can lead to dysbiosis and further to the development of a pathological condition
such as IBD.67, 68
In CD patients, for example, there have been described abnormal intestinal
permeability; abnormities of tight junctions;69
and dysfunction of goblet cells, Paneth cells,70
and M cells.63
Upon encountering antigen and microbial products gaining access through the
intestinal barrier, dendritic cells and other antigen-presenting cells initiate a cascade of proand
anti-inflammatory signals.71
This results in the activation of various subsets of local and
circulating lymphocytes migrating to effector sites where inflammation occurs.63
All these
processes influence the innate response and production of various cytokines while affecting
the function of effector and regulatory cells. Dysregulated immunological reactions in the gut
that lead to imbalance in pro- and anti-inflammatory pathways involved in innate and adaptive
immunity are regarded as fundamental to the development and persistence of inflammation in
IBD.72
4.2. Environment
The available evidence suggests that environmental exposures have variable effects on
individuals with IBD.73
In a study by Elten et al., for example, greater exposure to residential
greenspace during childhood was associated with reduced IBD risk, thus suggesting a novel
avenue to IBD prevention in children.74
The same study group revealed associations between
maternal and early-life exposures to air pollutants and risk of pediatric-onset IBD diagnosis.75
In a national case-control study in Sweden, higher cumulative exposure to systemic and
particularly broad-spectrum antibiotic therapy was associated with greater risk of new-onset
IBD and its subtypes.76
Moreover, greater adherence to a Mediterranean diet was associated
with significantly lower risk of later-onset CD in two prospective studies by Khalili et al.77
Among environmental factors, diet is widely thought to play a crucial role in IBD
19
development. A positive explanation could be that dietary habits have an essential role in
defining the composition of the human gut microbiota and patients suffering from IBD show a
generalized decrease in bacterial biodiversity and reduction in specific taxa, including
Firmicutes, Bacteroidetes, Lactobacillus, and Eubacterium.78
An umbrella review of available
meta-analyses identified nine factors that increase the risk of IBD: smoking (CD), urban
living (CD and IBD), appendectomy (CD), tonsillectomy (CD), antibiotic exposure (IBD),
oral contraceptive use (IBD), consumption of soft drinks (UC), vitamin D deficiency (IBD),
and non-Helicobacter pylori-like enterohepatic Helicobacter species (IBD). Furthermore,
seven factors reduce the risk of IBD: physical activity (CD), breastfeeding (IBD), bed-sharing
(CD), tea consumption (UC), high levels of folate (IBD), high levels of vitamin D (CD), and
Helicobacter pylori infection (CD, UC, and IBD).79
Nevertheless, the impact of modifying
specific environmental factors on risk of disease, risk of disease progression, and risk of
relapse remains inadequately studied, there being only limited high-quality data available
from interventional studies.80, 81
4.3. Genetics
Studies of genetic context in IBD have gradually used various approaches reflecting advances
in genetic testing (family and twin studies, linkage studies, candidate gene association studies,
genome-wide association studies).82
Genome-wide association studies (GWAS) alone have
revealed the majority of information related to the genetics of IBD, showing that complex
genetic disorders like IBD are polygenic, being driven by multiple, common genetic
polymorphisms.63, 83
To date, GWAS and post-GWAS deep resequencing studies have
identified 240 IBD-associated loci.41, 84
Nevertheless, as many as 80–90% of GWASidentified
loci are confined to noncoding variation that exerts its pathogenic effects through
modulation of gene expression. Recent studies have focused upon small intranuclear
molecules that can broadly regulate gene expression, such as epigenetic markers, microRNAs,
and non-coding RNAs, all of which have been implicated in the pathogenesis of IBD through
different pathways and will be discussed later.63, 85
4.4. Authors’ contribution to the knowledge
The family of noncoding RNAs (ncRNAs) exhibits a variety of biological functions.86
Noncoding RNAs can be divided according to their function into two groups: housekeeping
ncRNAs (e.g., tRNAs, rRNAs, snRNAs, snoRNAs) and regulatory ncRNAs. Transcripts
20
shorter than 200 nucleotides are termed short noncoding RNAs and transcripts exceeding 200
nucleotides are called long noncoding RNAs. Both groups are involved in regulating gene
expression and operate on several levels depending on their types. The short ncRNAs, such as
microRNAs (miRNAs), small interfering RNAs (siRNAs), and PIWI-interacting RNAs
(piRNAs), are involved mostly in post-transcriptional regulation but also in many other
specific processes such as transposon silencing or ribosomal RNA maturation.85, 87
The
ncRNAs have emerged as potential biomarkers for several diseases, as these are generally
stable and abundantly present in a variety of clinical specimens, including tissues and bodily
fluids; are highly tissue-specific, cell type-specific, and condition-specific; and can be readily
detected by routine and inexpensive laboratory techniques.85, 88, 89
Several miRNAs and
specific miRNA signatures have been identified in IBD-associated tissues, including serum,90
intestinal mucosa,91, 92
and stools.93, 94
Among many other cellular processes, it has been
shown that miRNAs play a significant role in intestinal immunity. In our article (Annex 3),
we provided an overview of current knowledge on ncRNAs, their altered expression profiles
in pediatric IBD patients, and how these are emerging as potentially valuable clinical
biomarkers.85
Figure 4 depicts tissue miRNAs involved in the development of PIBD.85
21
Figure 4. Tissue miRNAs involved in the development of pediatric IBD.
Abbreviations: TLR, toll-like receptor; TNF, tumor necrosis factor; ANCA, anti-neutrophil
cytoplasmic antibodies; IFN, interferon; TIMP, tissue inhibitor of metalloproteinases; MMP,
matrix metalloproteinase; Bcl2, B-cell lymphoma 2; BAX, BCL2 associated X; CCL, CC
chemokine ligand; CCR, CC chemokine receptor; ompC, outer membrane protein C
precursor. The figure is modified from Park et al.95
and had been published in Jabandziev et
al.85
22
5. Diagnostics
Diagnosis of IBD is based on the Revised Porto criteria.16, 31
In the Czech Republic, national
recommendations based upon these criteria are available.96, 97
Accurate diagnosis should be
based on a combination of history, physical and laboratory examination,
esophagogastroduodenoscopy, and ileo-coloscopy with obtaining mucosal samples for
histological examination and imaging of the small bowel, if indicated.16
It is necessary to
exclude other diseases mimicking the symptoms of IBD.16
Thus, we should rule out possible
intestinal infection, allergic diseases, and many others; determine the basic subtype of IBD
(UC, CD, UIBD), extent of the disease (Paris classification),35
activity of the disease (using
Pediatric Crohn’s Disease Activity Index [PCDAI]98-100
and the Pediatric Ulcerative Colitis
Activity Index [PUCAI]);101, 102
and the behavior of the disease.96
Table 3 presents the overall
comparative characteristics of CD and UC.103
Table 3. Multiple characteristics of Crohn’s disease and ulcerative colitis.
Clinical features Crohn’s disease Ulcerative colitis
Symptoms and signs Abdominal pain, diarrhea,
weight loss, anorexia,
growth failure
Bloody diarrhea, abdominal pain
Location Mouth to anus; involves all
layers of the gut: mucosa to
serosa; most common:
ileocolonic
Colon; involves only mucosa; most
common: pancolitis
Endoscopic findings Segmental distribution,
aphthous ulcers, deep
fissuring ulcers,
cobblestoning, perianal
disease, strictures, fistulas
Diffuse and continuous erythema,
friability, granularity, loss of
vascular pattern from rectum to
variable extent
Histological findings Pathognomonic noncaseating
granulomas;
patchy cryptitis, crypt
abscesses, ileitis
Cryptitis, crypt abscesses, crypt
architectural distortion, basal
lymphocytosis, distal Paneth cell
metaplasia
Radiologic findings Rigid stenotic segments, skip
areas, and sinus tracts or
fistulas
Dilatation of colon in toxic
megacolon
Figure was prepared in accordance with Oliveira et al.103
23
5.1. Patient’s history, symptoms, and clinical examination
Only few aspects are given greater emphasis in the literature than the importance of a detailed
evaluation of the patient’s history and a thorough clinical examination, including a careful
examination of the perianal area. This is in contrast with the fact that this often is not done in
routine clinical practice.104
IBD is manifested by a wide range of symptoms, both intestinal
and extraintestinal.105
Although typical symptoms from gastrointestinal tract affection are
usually at the forefront, IBD could first present as extra-intestinal manifestations.106
These
include erythema nodosum, pyoderma gangrenosum, episcleritis, uveitis, arthritis, and
others.107
Clinical manifestations of CD in children may include fatigue, weight loss,
abdominal pain, diarrhea, anemia, growth failure, and delayed puberty.2
UC is characterized
by inflammatory affection of the colon. Typical symptoms include crampy abdominal pain,
diarrhea, and rectal bleeding. The clinical symptomatology also depends on the extent of the
disease; according to the Paris classification,35
the disease can be divided into isolated
proctitis, left-sided colitis, extended colitis, and pancolitis. Pancolitis is very common in
children and affects about three-quarters of patients.108
5.2. Laboratory tests
Baseline tests include erythrocyte sedimentation rate, complete blood count, liver enzymes,
albumin, and C-reactive protein (CRP).16, 96
Use of serum antibodies remains complementary
in clinical practice, and serology may have a role in assessing prognosis (e.g., p-ANCA,
ASCA).109
Nevertheless, normal blood tests cannot exclude PIBD. Almost one-tenth of all
IBD patients diagnosed in a study by Ashton et al. had normal values for all widely used
blood tests, and even more than 20% of patients had normal CRP.110
In comparing widely
used laboratory tests in UC and CD, normal inflammatory markers were more common in
UC. UC was more likely to have abnormal liver enzymes and all normal results. CD was
more likely to have abnormal ESR, CRP, hemoglobin, platelets, and albumin.110
In recent years, fecal calprotectin (FCP) testing has gained relatively high clinical
popularity and widespread use.111
In a recent study by Walker et al., FCP testing of children
with suspected IBD accurately distinguished IBD from a functional gut disorder, reducing
secondary care referrals and associated utilization of diagnostic health care.112
Nevertheless,
clinicians must also be aware of the potential methodological limitations of FCP examination
in routine practice.113, 114
Evidence regarding the clinical use and value of FCP measurements
24
in various gastrointestinal disorders in children were reviewed in a recently published position
paper from ESPGHAN. Currently, FCP’s main use lies in the diagnosis and monitoring of
IBD and its differentiation from functional gastrointestinal disorders.115
Consensus statements have recently been published regarding prognostic laboratory
(and clinical) factors for such important clinical questions, among others, as need for surgery
and disease complications with regard to CD116
and UC.117
5.3. Endoscopic examination
Endoscopy has an essential and irreplaceable role in the diagnosis and management of PIBD.
It is used to differentiate IBD subtypes, monitor disease activity, assess response to therapy,
and treat possible complications.118, 119
Various endoscopic scoring systems are used in both
research and clinical practice,120
including, among others, Simple Endoscopic Score for
Crohn's Disease (SES-CD),121
Ulcerative Colitis Endoscopic Index of Severity (UCEIS),122
and Rutgeerts score123
for predicting the postoperative recurrence in CD patients after
ileocolonic resection. Revised Porto criteria recommend performing upper gastrointestinal
endoscopy and ileo-colonoscopy with multiple biopsies for all suspected patients with PIBD,
as well as small bowel imaging (unless typical UC is determined after endoscopy and
histology) by magnetic resonance enterography or wireless capsule endoscopy.16
Currently,
recommendations are generally available for endoscopy in pediatrics, including indications
for diagnostic and therapeutic esophagogastroduodenoscopy and ileo-colonoscopy,
stricture/stenosis endoscopic management, endoscopic solving of upper and lower
gastrointestinal bleeding; and others.124, 125
Recommendations for training and ongoing skills
maintenance in pediatric endoscopy have recently been published.126
In pediatrics, performing
an endoscopic examination means, in most cases, undergoing general anesthesia. It is
essential to determine the optimal examination strategy in the diagnosis of patients with
chronic conditions such as non-bloody diarrhea and abdominal pain. In a study from de Vijver
et al., evaluating symptoms and blood and stool markers in patients with non-bloody diarrhea
was found to be the optimal test strategy that allowed for reserving diagnostic endoscopy only
for children at high risk for IBD. This approach allowed minimizing exposure to endoscopy in
children.127
25
5.4. Histomorphologic examination
Collaboration with a pathologist is essential, and the pathologist is part of the
multidisciplinary team caring for pediatric IBD patients. Very important is to share clinical
data with the pathologist. Differential diagnosis between CD and UC can be particularly
challenging, such as when there are atypical presentation patterns for UC and Crohn’s
colitis.128
Extremely important is obtaining mucosal biopsies from all parts of the
gastrointestinal tract in IBD patients, and missing biopsies from grossly normal tissue would
have missed abnormal histology.129
It should be emphasized that diagnostic gastrointestinal
biopsies in VEO-IBD patients differ from those occurring with older onset of PIBD and
include broader differential diagnosis (e.g., autoimmune enteropathy).130
Supplemental
(special) stains based upon a patient’s clinical history are needed in special situations and
must take into account the local differential diagnostic situation, such as in low-resource
countries.131, 132
5.5. Imaging methods
The noninvasive nature of imaging makes it an ideal tool for serial assessment of disease
activity and treatment response. The choice of imaging (bowel ultrasonography, computed
tomography, magnetic resonance imaging, etc.) should be based on the specific advantages
and disadvantages of each (ionizing radiation, availability, reproducibility, length of
examination, cost).103
For example, while ultrasound is a widely used, safe, fast, and low-cost
method both for children suspected of IBD and for monitoring children with IBD,133
the
diagnostic accuracy of ultrasound in detecting intestinal inflammation remains
inconclusive.134
5.6. Examples of modern diagnostic methods potentially useful in clinical practice
Although we have a fairly wide range of tools at our disposal for adequate diagnosis of IBD,
several alternative diagnostic techniques have been developed recently. Various noninvasive
markers are currently available, but they have limitations and do not provide ideal utility.135
In
pediatric and adult patients, we can often encounter diagnostic delays.17, 18
Thus, it would be
highly advantageous to have tools to predict whether patients will develop IBD at all. For
example, Torres et al. identified a panel of 51 protein biomarkers (e.g., complement cascade
proteins, lysosomes, glycosaminoglycans) that were predictive of Crohn’s disease within 5
26
years. On the other hand, predictive factors for the development of UC could not be found.136
It is clear that further research efforts are needed in this field. Recently, several studies have
investigated serum dipeptidyl peptidase-4 as a biomarker of IBD severity and also as a
predictor of subclinical disease activity, but with conflicting results.137-139
Serum profiling and
non-coding RNAs are just starting to become widely used but reveal great promise for future
clinical practice. Non-coding RNAs and their role in IBD are among the author’s main
scientific focus areas and are discussed elsewhere.85, 140
In any case, combining different
serum biomarkers can be valuable in improving the performance of disease evaluation.141
Studies have recently revealed as potentially promising new fecal biomarkers of
intestinal inflammation calgranulin-C (S100A12), tumor pyruvate kinase isoenzyme type M2
(TuM2-PK), and fecal osteoprotegerin (FOPG).142
Fecal calgranulin-C and FCP had excellent
test characteristics to predict IBD and justify endoscopy in a study by Heida et al.143
Moreover, calgranulin C appears to be a more suitable maker for predicting mucosal healing
in children with IBD.142
Other, less well-established fecal biomarkers include high mobility
group box 1 (HMGB1), chitinase 3-like 1, defensins, matrix metalloproteinases, and human
nucleic acid. Most of these still require further extensive evaluations and validation.135
New endoscopic methods can be expected to emerge and be applied in clinical
practice. In the case of UC, for example, magnification colonoscopy, endocytoscopy, and
confocal laser endomicroscopy (CLE) enable assessing histological inflammation without the
need for biopsy.144
Concretely, CLE allows visualization of mucosal abnormalities and thus in
vivo histology during ongoing endoscopic evaluation by identifying macroscopically normalappearing
mucosa, assessing intestinal epithelial barrier function and vascular permeability,
and characterizing potential mucosal lesions, including dysplastic lesions. In particular, CLE
used in conventional endoscopy could facilitate the assessment of mucosal healing in IBD.145
In a pilot study by our study group, we evaluated CLE’s usefulness in diagnosing esophageal
diseases and came to promising results.146
Massively parallel sequencing, also termed next-generation sequencing (NGS), is
increasingly used in clinical practice. Its high capacity creates new opportunities for NGS’s
clinical application for establishing disease diagnoses and prognoses and in making
therapeutic decisions.42, 147
27
Targeted sequencing is the NGS assay most commonly used. Typically, it interrogates
tens or hundreds of genes presumed to be associated with a particular clinical phenotype or
group of diseases. Targeted NGS panels are today very time- and cost-effective.
A specific type of targeted NGS assay, known as whole-exome sequencing (WES),
analyzes all of a genome’s protein-coding regions. It is particularly beneficial in cases of
disorders that are phenotypically heterogeneous and when it is difficult to select an
appropriate panel of candidate causative genes. Despite its clear advantages, WES also has
some limitations, such as that intronic and noncoding regions remain uncovered and
sequencing quality (often expressed as sequencing depth) is insufficient for particular genes,
precisely because the range of targeted regions is so very large. Because NGS technology
produces huge amounts of data, the processing and storage of that information represents a
considerable bioinformatic challenge.148
When properly selected and used, NGS technologies
provide excellent tools that greatly expand the range of genes analyzed and can contribute
importantly to ensuring adequate preventive and therapeutic procedures for patients at risk.39,
42, 147
This is evidenced by use of the methodology in our patients, as documented in the
articles discussed in this work.42, 149
5.7. Authors’ contribution to the knowledge
Despite advances in IBD diagnostics and therapy, there is still a need for biomarkers to
accurately identify IBD patients and predict treatment response.85
This knowledge could
ultimately lead to more individualized approaches to patients. The identification of patients at
high risk for a complicated disease course could then be crucial.150, 151
In the article by Jabandziev et al. (Annex 4),140
we stratified therapeutically naive
pediatric patients diagnosed with UC pancolitis according to the severity of their condition
and prediction for standard treatment according to the specific expression of 10 candidate
miRNAs that we identified in a previous review paper.85
The work was created during the
author’s time in the laboratory of Prof. Ajay Goel, at the Department of Molecular
Diagnostics and Experimental Therapeutics, Beckman Research Institute of City of Hope, Los
Angeles, CA, USA. The study enrolled therapeutically naïve, pediatric UC patients only with
confirmed pancolitis. We examined formalin-fixed paraffin-embedded specimens of colonic
tissue for expression of 10 selected candidate miRNAs. We performed receiver operating
characteristic curve analysis, using area under the curve and a logistic regression model, to
28
evaluate the diagnostic and predictive power of the miRNA panels. The final analysis
included 60 patients. As a control group, 18 children without macroscopic and microscopic
signs of inflammatory bowel disease were examined. A combination of three candidate
miRNAs (let-7i-5p, miR-223-3p, and miR-4284) enabled accurate detection of pediatric UC
patients and controls (Figure 5). A panel of four candidate miRNAs (miR-375-3p, miR-146a-
5p, miR-223-3p, and miR-200b-3p) was associated with UC severity in pediatric patients, and
another combination of three miRNAs (miR-21-5p, miR-192-5p and miR-194-5p) was
associated with early relapse of the disease. Nine patients out of the total were diagnosed with
primary sclerosing cholangitis simultaneously with ulcerative colitis. A panel of 6 candidate
miRNAs (miR-142-3p, miR-146a-5p, miR-223-3p, let-7i-5p, miR-192-5p, and miR-194-5p)
identified those patients with primary sclerosing cholangitis. Specific combinations of
miRNAs show promise as tools for potential use in precise disease identification and severity
and prognostic stratification in pediatric patients with ulcerative pancolitis.140
29
Figure 5. Diagnostic accuracy of 3-miRNA panel for identifying UC patients.
(A) The adaptive LASSO model. (B) A correlation matrix displaying Spearman’s rank
correlation coefficient for each pair of three selected miRNAs. (C) Principal component
analysis illustrating the good separation of UC-patient group and control group. (D) ROC
curves for detecting UC patients using the 3-miRNA panel. (E) A waterfall plot representing
risk score of each patient. Red and blue columns indicate UC patients and controls,
respectively. A heat map illustrating expression levels of the three candidate miRNAs
expressed differentially between UC patients and controls. The figure had been published in
Jabandziev et al.140
30
6. Differential diagnostics
In the diagnostics of children with suspected IBD, it is necessary to differentiate a relatively
wide range of diseases that may be similar in their symptoms to the manifestations of IBD.30
Patients’ history and specific clinical signs should always be taken into account. In thinking
about differential diagnostics, it is necessary to consider (and also to exclude if possible)
infectious causes, immune-inflammatory disorders, vascular ischemic disorders, drug-induced
colitis, and many others.152
Possible IBD-mimicking diseases are summarized in Table 4.153,
154
Particularly very challenging in differential diagnosis can be to manage patients with
VEO-IBD. Therefore, this topic is discussed in a following separate chapter.
Table 4. Differential diagnostics of IBD-mimicking diseases.
Infection bacterial Campylobacter jejuni, Salmonella sp., Shigella dysenteriae,
Yersinia enterocolitica, enteroinvasive E. coli, Clostridium
difficile etc.
viral Norovirus, Rotavirus, Coronavirus, Adenovirus, Echovirus,
Cytomegalovirus, Herpes simplex virus type 2 etc.
parasitic Giardia lamblia, Entamoeba histolytica, etc.
fungal Candida crusei, Candida glabrata etc. (especially in
immunocompromised patients)
toxins Vibrio cholerae (choleragen), Staphylococcus aureus (enterotoxin
A-E), Clostridium difficile (toxin A, B) etc.
Drugs
(drug-induced
colitis)
microscopic
colitis
non-steroidal anti-inflammatory drugs, proton pumps inhibitors,
statins, β-blockers, etc.
macroscopic
colitis
chemotherapeutic drugs (e.g., taxane, platinum),
immunomodulators (e.g., infliximab, adalimumab), laxatives,
antibiotics etc.
inflammatory
colitis
non-steroidal anti-inflammatory drugs, immune checkpoint
inhibitors (nivolumab) etc.
Vascular-
ischemic
disorders
Henoch-Schönlein purpura, systemic vasculitis (dermatomyositis,
systemic lupus erythematodes), granulomatosis with angiitis
Immune-
inflammatory
(including
monogenetic
diseases)
eosinophilic gastroenteritis, severe combined immunodeficiency
syndrome, common variable immunodeficiency diseases,
interleukin-10 signaling defects, chronic granulomatous disease,
X-linked lymphoproliferative syndrome type 1,2, Wiskott-Aldrich
syndrome, Omenn syndrome, congenital neutropenia, Behcet’s
disease, autoimmune enteropathy, agammaglobulinemia,
mevalonate kinase deficiency, etc.
Other coeliac disease, lactose intolerance, irritable colon syndrome,
glycogen storage disease type b, radiation colitis, intestinal
lymphoma, Hermansky-Pudlak syndrome, trichohepatoenteric
syndrome, sarcoidosis, laxative abuse, etc.
Table was prepared in accordance with Kliegman et al.153
and Hamdeh et al.154
31
6.1. Very-early-onset IBD
In VEO-IBD patients who do not respond to standard therapy, we must consider the possible
presence of primary immunodeficiency. This possibility should be considered especially in
children under 2 years of age. A phenotypic aide-memoire summarizing key findings to
ensure that a careful clinical history for VEO-IBD and examination are made to narrow the
search for an underlying monogenetic defect is: YOUNG AGE MATTERS MOST (YOUNG
AGE onset, multiple family members and consanguinity, autoimmunity, thriving failure,
treatment with conventional medication fails, endocrine concerns, recurrent infections or
unexplained fever, severe perianal disease, macrophage activation syndrome and
hemophagocytic lymphohistiocytosis, obstruction and atresia of intestine, skin lesions and
dental and hair abnormalities, and tumors).38
Warning signs that could ideally lead to
suspicion of monogenic VEO-IBD or IBD-like disease are summarized in Table 5.38
Table 5. Warning signs for suspecting monogenic IBD.
Key points Comments
Very early age onset of IBD-like immunopathology Likelihood increases with very early onset, particularly in
those younger than 2 years of age at diagnosis
Family history In particular, consanguinity, predominance of affected
males in families, or multiple family members affected
Atypical endoscopic or histological findings For example, extreme epithelial apoptosis or loss of
germinal centers
Resistance to conventional therapies Such as exclusive enteral nutrition, corticosteroids, and/or
biological therapy
Skin lesions, nail dystrophy, or hair abnormalities For example, epidermolysis bullosa, eczema, folliculitis,
pyoderma or abscesses, woolly hair, or trichorrhexis
nodosa
Severe or very early onset perianal disease Fistulas and abscesses
Lymphoid organ abnormalities For example, lymph node abscesses, splenomegaly
Recurrent or atypical infections Intestinal and non-intestinal
Hemophagocytic lymphohistiocytosis Induced by viral infections such as Epstein-Barr virus or
cytomegalovirus, or macrophage activation syndrome
Associated autoimmunity For example, arthritis, serositis, sclerosing cholangitis,
anemia, and endocrine dysfunction, such as thyroiditis and
type 1 diabetes mellitus
Early development of tumors For example, non-Hodgkin lymphoma, skin tumors,
hamartoma, thyroid tumors
Table was prepared in accordance with Uhlig et al.38
32
Physical findings and comorbidities of which physicians should be aware in suspicion of
monogenic VEO-IBD or VEO-IBD-like syndromes at the initial physical examination and
during follow-up are depicted in Figure 6.155
Figure 6. Key indicators of monogenic IBD in clinical practice.
In parentheses after the listed comorbidities and specific clinical findings are genes whose
mutations are responsible for the disease manifestations. Figure was prepared in accordance
with Nambu et al.155
and created in collaboration with the Service Center for E-Learning at
Masaryk University, Faculty of Informatics.
Certainly, a subset of the more aggressive, therapy-resistant VEO-IBDs, which have recently
been regarded as associated with inborn errors of immunity (IEI), should be mentioned.28, 156
The updated IEI list from the International Union of Immunological Societies phenotypic
classification includes 406 IEI disorders with 430 gene defects.157
To date, more than 50
monogenic defects associated with IBD or IBD-like phenotype have already been
identified.158
Gastrointestinal manifestation of IEI is common and may precede the primary
diagnosis of IEI.156, 158
From a pathophysiological point of view, VEO-IBD related to IEI
manifests as a result of impaired barrier function of the intestinal epithelium, defects in
bacterial killing by phagocytes, increased hyper- or autoimmune inflammatory pathways, or
33
impaired development and function of the adaptive immune system.42, 97, 156, 158
The subgroups
of IEI-associated VEO-IBD are summarized in Table 6.28
Table 6. Inborn error of immunity-associated VEO-IBD groups
• Genetic variants influencing the integrity of intestinal barrier
• Genetic variants influencing bacterial recognition and clearance
• Genetic variants in the IL-10-IL-10R pathway and related cytokine family
members
• Genetic variants impairing regulatory T cells
• Genetic variants impairing development of the adaptive immune system
• Genetic variants resulting in autoinflammatory disorders
Table was prepared in accordance with Kelsen et al.28
Because the management of monogenic IBD is different from that for classical IBD, it
is crucial to identify these patients. The Paediatric IBD Porto Group of ESPGHAN recently
published a position paper covering indications, technologies (targeted panel, exome and
genome sequencing), gene panel setup, cost-effectiveness of genetic screening, and
requirements for the clinical care setting.39
It is clear from the above that the differential diagnosis of IBD and especially of the
VEO-IBD group is highly complex and challenging. Therefore, it should ideally be performed
in IBD centers having sufficient experience and capability to perform adequate diagnosis.159
6.2. Authors’ contribution to the knowledge
Phosphomannomutase-2 deficiency (PMM2-CDG)
Congenital disorders of glycosylation (CDG) comprise a large and heterogeneous group of
more than 130 monogenic diseases.160
CDG is caused by defects in the synthesis of glycans
and in the attachment of glycans to proteins and lipids. Clinical manifestation is
multisystemic.161, 162
The N-linked protein glycosylation defect PMM2-CDG
(phosphomannomutase-2 deficiency), previously known as CDG type Ia, was the first
reported CDG and remains the most common CDG to date.160
PMM2-CDG patients can be
divided into those with neurological and those with neurovisceral phenotype.163
Neurovisceral
phenotype includes heart (pericardial effusion and cardiomyopathy), liver (high serum
transaminases), and gastrointestinal (chronic diarrhea, feeding tube, and gastroesophageal
reflux) involvement.164, 165
In a retrospectively analyzed group of 96 French patients with
PMM2-CDG, the presenting signs were mostly neurological (hypotonia, intellectual
34
disability, cerebellar syndrome) and observed in almost all the patients. In addition to
neurological signs, a total of 38 patients exhibited visceral features including at least one of
the following: feeding difficulty requiring nutritional support (n=23), cardiac features (n=20;
pericarditis), hepato-gastrointestinal features (n=12; chronic diarrhea: 7, protein-losing
enteropathy: 1, ascites: 3, liver failure: 1, portal hypertension: 1), kidney features (n=4), and
hydrops fetalis (n=1).164
We described (Annex 5) an infant boy with PMM2-CDG and novel splicing mutation,
who presented with pericardial effusion, typical dysmorphic facial features, inverted nipples,
failure to thrive, and psychomotor retardation. Screening for CDG performed using isoelectric
focusing of serum transferrin showed a typical PMM2-CDG pattern. Exome sequencing
revealed one common pathogenic variant (c.691G > A/p.Val231Met) and one novel variant
(c.447 C 3dupA) in the PMM2 gene. Both PMM2 variants were further confirmed by Sanger
sequencing in both the proband and the parents’ DNA. The novel variant was predicted to
result in loss of donor splice site. Analysis at mRNA level confirmed that it leads to exon five
skipping (r.348_447del) and causes premature termination of translation to the protein
(p.G117Kfs-4).149
Although CGD-MM2 is a relatively rare disorder, it can have
gastrointestinal symptomatology and thus should be considered, especially in the differential
diagnosis of patients with suspected VEO-IBD or VEO-IBD-like syndromes.
MIRAGE syndrome
A 2016 paper reported on a group of 11 patients with a newly identified syndrome that was
termed MIRAGE.166
MIRAGE is an acronym for the significant findings of myelodysplasia,
infection, restriction of growth, adrenal hypoplasia, genital phenotypes, and enteropathy.
Gastrointestinal complications include chronic diarrhea and esophageal dysfunction.166
MIRAGE syndrome is an extremely rare disease. Several dozen patients have been described
so far.167-170
We described the case report of a patient with MIRAGE syndrome (Annex 6).171
The
author cared for this patient for a long time at our department in the intensive care unit and
ambulatory care. The reported patient had a novel mutation in SAMD9 (c.2471 G>A,
p.R824Q), manifesting with prominent gastrointestinal tract involvement and
immunodeficiency. Among other major symptoms, he had difficulty swallowing, requiring
percutaneous endoscopic gastrostomy, frequent gastrointestinal infections, and perianal
35
erosions. He suffered from repeated infections and periodic recurring fevers with elevation of
inflammatory markers. At 26 months of age, he underwent hematopoietic stem cell
transplantation that significantly improved hematological and immunological laboratory
parameters. Nevertheless, he died at day 440 post-transplant due to sepsis. Even though it is a
sporadic disease, SAMD9 mutations should be considered as a cause of enteropathy in
pediatric patients, especially in combination with other described symptoms.171
Eosinophilic esophagitis
The finding of eosinophilic infiltration accompanies inflammatory diseases of the
gastrointestinal tract of various origins, and the differentiation of primary and secondary
forms is crucial for further diagnosis and treatment.172
Primary eosinophilic gastrointestinal
disorders (EGID) are a relatively new group of diseases. They can affect any part of the
gastrointestinal tract and are characterized by mucosal infiltration of eosinophils in the
absence of other causes for eosinophilia.173, 174
We can diagnose eosinophilic esophagitis,
eosinophilic gastritis, eosinophilic gastroenteritis, eosinophilic enteritis, and eosinophilic
colitis, or a combined involvement of different parts of the gastrointestinal tract.173
In
populations of Western countries, eosinophilic esophagitis is by far the most common form.172
These diseases present with a broad spectrum of often non-specific symptoms and with
differential diagnosis ranging from functional gastrointestinal diseases to severe organic
disorders, including IBD. Generally, clinical manifestation depends upon the location of
eosinophilic infiltration. The pathophysiology of EGID is still unclear. It seems that food and
aeroallergens play an essential role. The endoscopic appearance of EGID is not specific. A
combination of serious clinical suspicion and histopathologically proven dense eosinophilic
infiltration of the intestine are essential for diagnosis.174
Unfortunately, with the exception of
the esophagus, eosinophilic infiltration of the gastrointestinal wall is common.175
Furthermore, we can find eosinophils in mucosal specimens in the cases of many
inflammatory diseases, such as celiac disease, IBD, and parasitic infections. Moreover,
eosinophilic infiltration of the gastrointestinal tract may accompany hypereosinophilic
syndrome, vasculitis, as well as post-medicamentous and malignant diseases.176
In our observational survey (Annex 7),177
we aimed to characterize features of
eosinophilic esophagitis (EoE) diagnosed in five pediatric endoscopy centers and to describe
local strategies for its treatment. This analysis focused on describing their general situation
(age, gender, symptoms) and also aimed to investigate any possible linkage between age and
36
symptoms or length of diagnosis period. Demographic features; clinical symptoms;
laboratory, endoscopic, and histopathological findings; and chosen treatment of patients were
recorded and analyzed. We precisely described 33 new cases of children with EoE and their
clinical characteristics. To our best knowledge, this was the first retrospective study on
pediatric patients with EoE in the Czech Republic. We have proposed collecting long-term
prospective observational data into a national EoE register of patients in the Czech Republic,
as doing so would significantly improve our knowledge of this disease.177
Herpetic esophagitis
Endoscopic examination of the upper gastrointestinal tract comprises an integral part of the
diagnostics process in patients with suspected IBD.16, 125
Inflammation in upper
gastrointestinal tract is described in approximately half of the children with IBD during the
initial assessment. In a study by Castellaneta et al., the sites most frequently involved were the
stomach (67%) followed by the esophagus (54%) and duodenum (22%).178
From the
pathological point of view, among the manifestations of pediatric IBD in upper
gastrointestinal tract include lymphocytic esophagitis, focally enhanced gastritis, duodenal
inflammation, and epithelioid granulomas.179
In addition to IBD, differential diagnosis of
ulcerative esophagitis must consider esophageal infections (herpes simplex, cytomegalovirus,
varicella-zoster virus, candida, or various bacterial agents), trauma, esophageal burns, and
Behcet’s disease.180, 181
We described (Annex 8)181
the case report of a 7-year-old immunocompetent boy with
a suddenly occurring triad of symptoms: odynophagia, chest pain, and fever. In addition to
other standard examinations, we performed esophagogastroduodenoscopy, where significant
inflammatory changes transitioning to longitudinal ulcerations in the distal third of the
esophagus were revealed.181
In addition to the standard sampling of esophageal tissue, biopsy
material was also sent for bacteriological and mycological examination as well as for the
detection of herpes simplex virus (HSV) and cytomegalovirus by polymerase chain reaction
(PCR). The result of HSV DNA detection by PCR from the esophageal mucosa was positive.
Herpesvirus infections, in general, can complicate the course of IBD. Immunosuppressive
therapy appears to increase the risk of herpesvirus reactivation and predispose to more severe
infections. While cytomegalovirus colitis and systemic Epstein-Barr virus reactivation are
well known, HSV is rarely involved. When HSV infections do occur, they are usually
confined to sites of local reactivation, such as mucosal surfaces (e.g., the oropharynx,
37
anogenital region, and eyes) and sites on the skin. However, case reports describing
disseminated HSV infection with colonic involvement have been published.181, 182
The
presented work demonstrates the necessity to consider the possible presence of HSV infection
in differential diagnosis of endoscopic findings of gastrointestinal ulcerations.181
38
7. Therapy
The goals of treatment include to relieve disease symptoms, achieve intestinal healing, reach
growth potential, and optimize the quality of life while limiting drug toxicity.183
IBD therapy
has come a long way in recent decades, and it will probably continue to undergo intensive
development. There are national recommendations for the treatment of pediatric IBD
patients,96, 97
as well as recent international recommendations for the treatment of both UC
and CD.19-22
In an ideal situation, therapy of pediatric patients with IBD should be
individualized, using a risk-stratification approach and predictors of poor outcome.184
Treatment modalities could be divided into several groups, specifically medical therapy,
nutritional therapy, and endoscopic and surgical therapy. Experimental therapeutic modalities,
such as fecal microbial transplantation, plasma exchange, using of mesenchymal stromal
cells, and others, have also been studied.185-187
There also are some alternative approaches,
which some patients require and about which the treating physician should be informed.188
7.1. Medical therapy
Medical therapy has long been limited to so-called non-biological therapies (aminosalicylates,
thiopurines, and steroids). Together with a better understanding of the etiopathogenesis of
IBD, the development of biological therapy has been a significant advance in treatment.189
Currently, tumor necrosis factor-alpha inhibitors infliximab and adalimumab are approved for
use in pediatric patients in the Czech Republic. The use of other agents, such as ustekinumab
and vedolizumab, is only possible in the so-called “off label” regimen after approval by the
relevant health insurance company.97
It can be expected, however, that other and novel
therapies could enter the diagnostic repertoire of pediatric gastroenterologists. Generally, this
occurs after experience has been gained with new drugs in the treatment of adult patients.190
The new biologics and small molecule drugs block immune cell communication or migration.
Novel small molecules include Janus kinase (JAK) inhibitors (tofacitinib), small mothers
against decapentaplegic homolog (SMAD)7 antisense oligonucleotides (mongersen),
sphingosine-1-phosphate (S1P) receptor modulators (ozanimod, etrasimod), and
phosphodiesterase (PDE)4 inhibitors (apremilast). Other novel biologics include anti-integrins
(vedolizumab, natalizumab), anti-cytokines (ustekinumab, risankizumab, brazikumab,
mirikizumab, guselkumab), and anti-mucosal vascular addressin cell adhesion molecule-1
(MAdCAM-1) (etrolizumab).183, 191
Some of these drugs are already part of clinical practice,
while others are being tested in various phases of clinical trials.
39
Cases of children being treated with combinations of biological agents with relatively
promising results have already been described in the literature. Dual biological therapy could
thus potentially expand the range of treatment options.192
Figure 7 summarizes the different therapeutic agents and their site of action within the
pathophysiology of IBD.191
Figure 7. Therapeutic targets of novel biologics and small molecules for the treatment of
inflammatory bowel disease.
Biologics and small molecules are indicated by red and green colors, respectively. AMP,
adenosine monophosphate; cAMP, cyclic adenosine monophosphate; IEL, intraepithelial
lymphocyte; Iκb, inhibitor of κB; IL, interleukin; JAK, Janus kinase; MAdCAM-1, mucosal
vascular addressin cell adhesion molecule-1; NF-κB, nuclear factor-κB; P, phosphorylation;
PDE, phosphodiesterase; S1P, sphingosine-1-phosphate; SMAD, small mothers against
decapentaplegic homolog; STAT, signal transducer and activator of transcription; TGF-β,
transforming growth factor-β; TGF-βR, TGF-β receptor; TNF-α, tumor necrosis factor-α;
TNFR, TNF receptor. The figure was prepared in accordance with Na et al.191
and created in
collaboration with the Service Center for E-Learning at Masaryk University, Faculty of
Informatics.
40
7.2. Nutritional therapy
In pediatrics, nutritional therapy can be used for two reasons: to improve the nutritional status
of both UC and CD patients or as a means to induce remission in patients with a defined type
of CD (exclusive enteral nutrition).193
Recently, evidence has been published on the
possibility of combining enteral nutrition and a special diet in the treatment of CD (Crohn’s
Disease Exclusion Diet, CDED), suggesting very promising results.194, 195
At our department,
we have relatively good experience with this treatment modality. In the context of IBD
treatment, the effect of other diets has also been investigated, but with inconclusive results.196-
199
7.3. Endoscopic and surgical therapy
Endoscopic examination and follow-up is a common modality in managing patients with
IBD.125
Endoscopic instrumentation allows us, for example, to dilate possible stenoses.200
Surgical treatment has become a common part of comprehensive IBD treatment. In UC, this
involves mainly subtotal or total colectomy with the construction of ileo-anal pouch
anastomosis.201
In CD, it is often an ileocecal resection performed because of irreducible
inflammatory activity in this area, or resolution of symptomatic stenosis of the ileocecal
valve.202
The role of the surgeon in managing complications of perianal involvement (i.e.,
fistulas, abscesses) is indispensable.203, 204
7.4. Authors’ contribution to the knowledge
Ileocecal resection is an integral part of treating selected pediatric and adult patients with
CD,201, 205
despite the fact that, concurrently with the development of biological therapies, the
need for surgery is decreasing.206
The issue of predicting postoperative disease recurrence,
however, was not entirely clear. The aim of the study by Poredska et al. (Annex 9)207
was to
determine whether the histological activity of CD in resection margins after ileocecal
resection is associated with early endoscopic recurrence of the disease. This study was
conducted with adult patients, but some of these patients had been previously treated at the at
the authors’ workplace (i.e., the Department of Pediatrics). The resection line was always up
in macroscopically healthy tissue. Ileocecal resected specimens were histologically examined
for the presence of microscopic signs of CD, including both resection margins, that is, the
small and large intestine. At 6 months postoperatively, patients underwent a follow-up
41
colonoscopy during which endoscopic recurrence was assessed according to the Rudgeerts
score.208
We investigated whether histological findings in the resection margins correlated
with endoscopic recurrence of CD. Furthermore, the effects of preoperative therapy and other
risk factors associated with endoscopic recurrence were evaluated. Endoscopic recurrence of
CD at 6 months after surgery was observed in 23 patients out of a total of 107 enrolled.
Microscopic evidence of CD in the resection margins was associated with significantly higher
endoscopic recurrence in the anastomosis (56.5% versus 4.8%, p<0.001). Duration of disease
from diagnosis to surgery (p=0.006) and length of resected bowel (p=0.019) were
significantly longer in patients with proven endoscopic recurrence. Thus, it was shown that
microscopic evidence of CD in the resection line in cases of ileocecal resection was
significantly associated with a higher risk of early postoperative endoscopic recurrence. The
results of a recent meta-analysis, where our work was included, showed that positive resection
margins and myenteric plexitis and granulomas in the resection margins significantly
increased the risk for postoperative recurrence of CD.209
This is consistent with the results of
our study.207
42
8. Complications
This chapter will discuss complications, both within and outside the digestive tract, that are
so-called extraintestinal complications. It should be said that complications include here, from
a somewhat broader point of view, manifestations that may be present as initial manifestations
of the disease in individual patients (e.g., perianal fistulation). In the following text, the issue
of potential adverse effects of medicament therapy will not be discussed further.
8.1. Complications from within the gastrointestinal tract
Strictures can develop practically anywhere in the gastrointestinal tract, and especially in
patients with CD. These lesions may be asymptomatic or may require some type of
intervention (dilatation or surgical resection).210
Gastrointestinal fistulas are abnormal connections between the bowel and neighboring
organs. The occurrence of CD in childhood is associated with more aggressive development
of perianal fistulas. Fistulas can occur in almost one-third of patients within 5–7 years after
diagnosis.211
Fistula types include perianal, entero-cutaneous, entero-enteric, enteromesenteric,
recto-vaginal, and entero-vesical.212
Perianal fistulas are most common and
commonly cause severe infections, fecal incontinence, perianal discharge, negative selfimage,
and social isolation. Perianal fistulas significantly reduce the quality of life of patients
and are relatively difficult to treat,213
but the introduction of anti-TNF has improved patients
outcomes.183, 214
Toxic megacolon (TM) is one of the most feared complications of IBD, especially UC,
and should be considered in these patients.215
It is characterized by a combination of systemic
toxicity (fever, tachycardia, leukocytosis, altered mental status) and segmental or total
dilatation of the colon.216
TM is fraught with high morbidity and mortality and can require
surgical treatment. Various infections, especially Clostridium difficile, may also be a
causative factor in the development of TM.21, 212
Other complications include primary sclerosing cholangitis, orofacial granulomatosis,
and cholecystolithiasis.217-220
A feared long-run complication is malignancy, inasmuch as the
onset of IBD in childhood is associated with increased risk of any cancer, and especially of
gastrointestinal cancers, both in childhood and later in life.221
43
8.2. Extraintestinal and systemic complications
Approximately one-third of children with CD and as many as 10% of children with UC suffer
from growth impairment. The cause of growth failure is multifactorial and includes, for
example, decreased appetite and decreased peroral intake, increased metabolic demand,
malabsorption due to mucosal inflammation, growth hormone resistance due to inflammation,
and use of corticosteroids. Therefore, thorough monitoring of linear growth is extremely
important, and overall treatment effort should be directed to restoring normal growth.12, 222
Along with the above factors, even lower physical activity can lead to lower bone mineral
density,223
as a higher incidence of low bone mineral density in pediatric IBD patients has
been observed in children with CD. A higher rate of bone fracture in children with IBD was
reported to follow corticosteroid treatment.224
Patients with IBD also are at risk for
deficiencies of various micronutrients, such as iron, folate, vitamin B12, and vitamin D.12
Psychosocial influences are not negligible, as children with IBD can have higher rates of
depressive and anxiety disorders.225
Various body systems can be affected, including
musculoskeletal (arthritis, ankylosing spondylitis),226
integumentary system (erythema
nodosum, pyoderma gangrenosum),227
ophthalmological (iritis, episcleritis),228
urogenital
(calcium oxalate stones),229
hematological (anemia, thromboembolism)230, 231
and
immunological (infections).212, 232, 233
8.3. Authors’ contribution to the knowledge
In general, IBD and its treatment are associated with significant morbidity and highly
probable hospitalization.234, 235
Hospitalization alone increases the risk of infectious
complications.236
IBD patients, and especially those with more severe disease courses, often
require corticosteroids, biologics, and/or immunosuppressive agents. Underlying active
disease and treatment with immune-suppressing therapy contributes to an increased risk of
serious and opportunistic infections in these patients.235, 237
Moreover, beyond immunological
dysregulations commonly underlying IBD, risk factors for infections in children with IBD are
represented by rare monogenic disorders, including primary immunodeficiencies, poor
nutritional status, and, above all, in comparison to adults, more frequent need for early and/or
combined immunosuppressive and biologic therapies.232, 233
Sepsis is a syndrome shaped by pathogen factors and host factors (e.g., sex, race and
other genetic determinants, age, comorbidities, environment) with characteristics that evolve
over time.238, 239
What differentiates sepsis from infection is an aberrant or dysregulated host
response and the presence of organ dysfunction. The clinical and biological phenotype of
44
sepsis can be modified by preexisting acute illness, long-standing comorbidities, medication,
and interventions.240
Despite significant advances in research and treatment strategies, sepsis
remains among the most threatening conditions in intensive care units for children and
adults.241, 242
Considerable variabilities in the course of sepsis can be caused by, among other
things, variants of the genes encoding the individual components of the immune system.243
Only limited data was available describing the influence of single nucleotide polymorphisms
and their combinations on the risk for development and severity of the course of sepsis in the
pediatric population.244
In our study (Annex 10), we revealed statistically significant differences in the
structure of single nucleotide polymorphism combinations between the group of patients with
septic conditions and the control group, as well as between the group of patients with the most
severe conditions (severe sepsis, septic shock, and multiorgan dysfunction syndrome) and the
control group. This approach has made it possible to describe low-, medium- and high-risk
combinations of genetic polymorphisms in the development and subsequent severity of septic
conditions. The study described a total of 23 pediatric patients who died due to a septic
condition. One of these patients was treated for Crohn’s disease and died due to septic
shock.244
Septic complications are relatively rare in pediatric patients with IBD, but the
possibility for their occurrence should be kept in mind.245
45
9. Potential perspectives on further research
9.1. General perspectives on research in the field of IBD
Currently, research in the field of IBD is very intensive and the interest in this issue is
constantly increasing. Barash et al. mapped IBD research from the MEDLINE/PubMed
database for the 25-year period 1992 and 2016. A total of 18,653 relevant publications were
classified as IBD-related and further analyzed. The annual number of publications increased
almost 4-fold (from 354 to 1361) during the studied period.246
Despite recent advances in
research, however, the complexity of IBD still creates enormous challenges for researchers.247
Current research is not fully able to satisfactorily address important research questions.248
Further and deeper understanding of the pathophysiological processes in IBD would help to
discover relevant biomarkers that could be used in both diagnosis and treatment.81
A
promising concept could relate to functional integration of those -omes relevant to the
pathogenesis of IBD, such as the exposome, genome, epigenome, microbiome, and others,
forming the so-called IBD interactome.249, 250
This could be defined as a disease network
within which dysregulation of individual -omes causes intestinal inflammation mediated by
dysfunctional molecular networks controlling all biological events (Figure 8).250
Figure 8. Functional integration of -omes relevant to the pathogenesis of the IBD-forming
IBD interactome.
The hypothetical disease network on the right shows the various molecular hubs (white
nodes) of the network, which is regulated by central regulatory hubs (gray nodes). The figure
was prepared in accordance with Souza et al.250
and created in collaboration with the Service
Center for E-Learning at Masaryk University, Faculty of Informatics.
46
In step with a better understanding of the pathogenesis of IBD, the portfolio of therapeutic
options continues to expand. Nevertheless, new therapeutics can be costly, and patients may
stop responding to therapies or not respond to them in the first place. Therefore, there is a
growing need for more personalized therapy based on insights into the biology of the
underlying disease and a drive to change our approach from reactive treatment driven by
disease complications to proactive care to prevent disease sequelae.72
This thinking embraces
a clear desire to make medicine as individualized – or, more precisely, as personalized – as
possible. Personalized medicine involves identifying patients at high risk of progression and
complications and better characterizing patients who may respond preferentially to specific
treatments.251
In an even narrower sense, we have recently encountered the term precision
medicine. The concepts of personalized medicine and precision medicine are very similar, but
precision medicine also includes a multidisciplinary, data-driven approach to support better
clinical decision-making through a clear understanding of the molecular basis of an
individual’s disease.72
Precision medicine in this sense means tailoring treatment to the
individual patient and incorporating different data-driven (and multi-omics) approaches to
support accurate clinical decision-making. In the case of IBD, precision medicine would be of
significant benefit, as it would allow for early treatment that is both effective and appropriate
for the individual.72
In summary, there is a need to understand and predict the natural course
of IBD-disease susceptibility, activity, and behavior; to predict disease progression and
response to therapy; and to optimize current and develop new molecular technologies.252
Precision medicine could provide the ways to do just that. To achieve this, prospective
longitudinal cohort studies are needed to identify and validate precision medicine biomarkers
for predicting disease progression and for predicting and monitoring treatment response.
Methodological harmonization across studies together with the development of standardized
methods and infrastructure are key to achieving this goal.252
It should be borne in mind that
the overall situation can change quite a lot. After all, who among caregivers and patients
could have guessed the substantial changes to the routine management of IBD that we
experienced during the unexpected coronavirus disease 2019 (COVID-19) pandemic?253
9.2. Author’s perspectives on research in the field of IBD
Microbial dysbiosis and microRNA
Together with colleagues from the Department of Pathology, University Hospital Brno and
Central European Institute of Technology, we obtained grant funds from the Czech Health
47
Research Council for carrying out our research project entitled: Study on microbial dysbiosis
and microRNA deregulation as a basis of the therapy individualization in pediatric patients
with inflammatory bowel disease. Work on the project is already fully underway. As part of
this research, we will work with our biobank, where we already have material from more than
100 pediatric patients with newly diagnosed IBD. The specific aims of the project are to:
- identify miRNAs specific for IBD patients by global profiling of miRNA expression
in the tissues and stools of IBD patients compared to healthy control subjects and miRNAs
specific for different IBD subtypes (classes) by comparing miRNA expression profiles in
therapeutically naïve patients;
- establish an miRNA predictive panel to identify patients with good and bad response
to a standard therapeutic regimen;
- validate and analytically characterize candidate diagnostic, prognostic, and predictive
miRNAs on an independent cohort of IBD patients;
- analyze microbiome composition in stool and tissue biopsy samples and identify
specific changes in microbiome composition in IBD patients compared to healthy controls
and in patients with different IBD subtypes;
- compare levels of candidate diagnostic, prognostic, and predictive miRNAs in tissue,
stool and plasma and correlate these with specific changes in the composition of the intestinal
microbiome; and
- propose a prospective clinical trial verifying the clinical benefit of identified
miRNAs in improving the diagnostic and therapeutic approach to pediatric patients with IBD.
A schematic representation of the study design is depicted in Figure 9.
48
Figure 9. Schematic representation of the study design.
CD – Crohn’s disease; UC – ulcerative colitis; HC – healthy control.
Brain alterations in pediatric patients with IBD
Central nervous system (CNS) involvement has been reported in pediatric and adult IBD
patients, with both neurological and psychiatric phenomena.254-259
To date, there are not many
studies investigating directly affection of the CNS in CD, especially in children. Research on
possible cerebral involvement in IBD generally and CD specifically has been largely
marginalized and failed to capitalize on recent developments in magnetic resonance imaging
(MRI). In a cross-sectional pilot study, we searched for eventual macrostructural,
microstructural, and functional brain affection in children with CD early after the disease’s
onset. Nine pediatric CD patients within 2 years of disease development and at the same time
with their disease in remission (according to FCP and PCDAI) and nine healthy controls
underwent structural, diffusion-weighted imaging and resting-state functional MRI acquisition
in combination with extensive neuropsychological testing. While no differences in cortical
thickness between CD patients and healthy controls were found, alterations were detected in
diffusion tensor imaging parameters over vast cortical regions essential for regulation of the
autonomous nervous system, sensorimotor processing, cognition, and behavior. These
alternations were accompanied by generally increased functional and structural connectivity
49
(Figure 10). Although still requiring further validation in longitudinal projects enrolling more
significant numbers of subjects, this study sets out possible directions for further research.
The discussed data are from an article that is now under review at the journal Frontiers in
Pediatrics. In the future, we would like to seek grant funding to conduct a prospective study
on microstructural changes in the brain of pediatric patients after the diagnosis of IBD.
Figure 10. Results of parcellated analysis comparing Crohn’s disease patients and healthy
controls.
(A) fractional anisotropy, (B) mean diffusivity, (C) degree centrality, (D) amplitude of lowfrequency
fluctuations (no significant results), (E) structural connectivity, and (F) partial
functional connectivity regularized using ridge regression. Absence of significant results
(subcortical outcomes for mean diffusivity amplitude of low frequency fluctuations and
structural connectivity) is marked with “×”.
Paneth cells and interleukin 17
Toward better understanding IBD pathophysiology, we investigated, in cooperation with
colleagues from the Institute of Molecular Genetics of the Czech Academy of Sciences (IMG
CAS), the role of interleukin 17 (IL-17) on Paneth cells (PCs). Paneth cells are a highly
specialized cell type with many functions in intestinal physiology.260
Recently, there is
increasing evidence for a potential role of PCs in the development of ileal CD.261
As
50
mentioned above, microbiota composition regulation is essential for intestinal homeostasis
when it is known that IL-17 regulates antimicrobial peptide production on epithelial
surfaces.262
The effect of IL-17 on PCs is nevertheless still unclear. We showed that PCs
express high levels of surface IL-17 receptor (IL-17R), and targeted ablation of IL-17R in PCs
decreases the cellularity of ileal PCs and the expression of their enteric α-defensins. Mice
with PCs lacking IL-17R showed upregulated inflammatory pathways and higher severity of
induced ileitis. These changes were associated with lower gut microbiota diversity, capable of
inflicting death upon its transfer to genetically susceptible mice. Strikingly, a sub-cohort of
pediatric patients with newly diagnosed Crohn’s disease displayed a low number of ileal PCs,
high ileitis severity score, and diminished serum levels of IL-17, thereby resembling the
phenotype of mice with IL-17R-deficient PCs. Our study identified IL-17 signaling in PCs as
an essential contributor to ileal homeostasis acting via the prevention of dysbiosis (Figure 11).
The discussed data are from an article that is now under review at the journal Cell Reports.
We will continue our cooperation with IMG CAS on research in this field.
51
Figure 11. Patients with CD manifest low ileum PC numbers, which correlate with low serum
IL-17 and terminal ileitis.
(A–C) Immunofluorescence microscopy analysis of frozen ileum biopsies from CD and nonIBD
patients. Sections were stained with lysozyme (PCs, green) and DAPI (nuclei, blue). (A)
Graph shows average numbers of PCs in patient/biopsy per crypt. (B) The PC number shows
bimodal distribution in CD patients. The number of PCs per crypt is plotted arbitrarily for
non-IBD and CD individuals, together with the best normal (dashed curve) and bimodal
normal (full line) fits to the data, respectively. All samples in the CD-PCLow group of CD
patients lie below the first percentile of non-IBD individuals and CD-PCNorm patients
(horizontal dashed line). Non-IBD n=5, CD-PCNorm n=11, and CD-PCLow n=5. (C)
Representative images of ileum crypts from non-IBD patients (left), CD-PCNorm (middle),
and CD-PCLow patients (right). Scale bar represents 10 μm. (D) Level of IL-17A measured
by ELISA in the serum of patients analyzed and stratified in B (sera were not available from 3
patients in CD-PCNorm and 1 patient in the CD-PCLow cohort). Data shown was tested by
Student’s t-test. (E) Representative ilea hematoxylin and eosin staining (left) and
histopathology scoring (right) from biopsies of patients analyzed and stratified in B. Scale bar
represents 50 μm. Data in (A), (D), and (E) have been tested by Student’s t-test.
p-values >0.05 are shown. *, p<0.05; ****, p<0.0001. Horizontal lines show mean±SEM.
52
10. Conclusions
Comprehensive management of IBD patients, especially in children, is a major challenge for
gastroenterologists and other health care professionals worldwide. In addition to its
complexity, however, it represents a fascinating and dynamically changing field of medicine
to which it is worth devoting one’s efforts. The approach to diagnosis, follow-up, and
management of IBD has undergone a major transformation in recent decades and can be
expected to continue dynamically to evolve. Together with colleagues, we intend to continue
research in this area. We would be delighted if our findings would, at least in part, contribute
to better care for pediatric IBD patients.
53
List of abbreviations
CD Crohn’s disease
CDED Crohn’s disease exclusion diet
CDG congenital disorders of glycosylation
CLE confocal laser endomicroscopy
CRP C-reactive protein
EGID eosinophilic gastrointestinal disorders
EoE eosinophilic esophagitis
ESPGHAN European Society of Paediatric Gastroenterology, Hepatology and Nutrition
FCP fecal calprotectin
FOPG fecal osteoprotegerin
GWAS genome-wide association studies
HMGB1 high mobility group box 1
HSV herpes simplex virus
IBD inflammatory bowel disease
IBDU inflammatory bowel disease unclassified
IEI inborn errors of immunity
IL-17 interleukin 17
JAK Janus kinase
MAdCAM-1 mucosal vascular addressin cell adhesion molecule-1
miRNAs microRNAs
MRI magnetic resonance imaging
ncRNAs noncoding RNAs
NGS next-generation sequencing
PCDAI Pediatric Crohn’s Disease Activity Index
PCR polymerase chain reaction
PCs Paneth cells
PDE phosphodiesterase
PIBD pediatric inflammatory bowel disease
piRNAs PIWI-interacting RNAs
54
PMM2 phosphomannomutase 2
PUCAI Pediatric Ulcerative Colitis Activity Index
RNA ribonucleic acid
S1P sphingosine-1-phosphate
siRNAs small interfering RNAs
SMAD small mothers against decapentaplegic homolog
THES trichohepatoenteric syndrome
TM toxic megacolon
TuM2-PK tumor pyruvate kinase isoenzyme type M2
UC ulcerative colitis
VEO-IBD very-early-onset inflammatory bowel disease
WES whole-exome sequencing
55
List of Figures
Figure 1. Clinical data of the patient with trichohepatoenteric syndrome. ............................. 12
Figure 2. Incidence rates per 100,000/year among children (0–18 years of age) newly
diagnosed with IBD (A) and CD (B) in South Moravian Region, 2002 to 2017 and 2018 to
2022.......................................................................................................................................... 16
Figure 3. Mechanisms involved in the pathogenesis of inflammatory bowel disease. ........... 17
Figure 4. Tissue miRNAs involved in the development of pediatric IBD. ............................. 21
Figure 5. Diagnostic accuracy of 3-miRNA panel for identifying UC patients...................... 29
Figure 6. Key indicators of monogenic IBD in clinical practice............................................. 32
Figure 7. Therapeutic targets of novel biologics and small molecules for the treatment of
inflammatory bowel disease..................................................................................................... 39
Figure 8. Functional integration of -omes relevant to the pathogenesis of the IBD-forming
IBD interactome. ...................................................................................................................... 45
Figure 9. Schematic representation of the study design.......................................................... 48
Figure 10. Results of parcellated analysis comparing Crohn’s disease patients and healthy
controls..................................................................................................................................... 49
Figure 11. Patients with CD manifest low ileum PC numbers, which correlate with low serum
IL-17 and terminal ileitis.......................................................................................................... 51
56
List of Tables
Table 1. Paris classification for Crohn’s disease..................................................................... 10
Table 2. Paris classification for ulcerative colitis.................................................................... 10
Table 3. Multiple characteristics of Crohn’s disease and ulcerative colitis. ........................... 22
Table 4. Differential diagnostics of IBD-mimicking diseases. ............................................... 30
Table 5. Warning signs for suspecting monogenic IBD.......................................................... 31
Table 6. Inborn error of immunity-associated VEO-IBD groups............................................ 33
57
References
1. Mulder DJ, Noble AJ, Justinich CJ, Duffin JM. A tale of two diseases: the history of
inflammatory bowel disease. J Crohns Colitis. 2014;8(5):341-8.
doi:10.1016/j.crohns.2013.09.009
2. Lee YA, Chun P, Hwang EH, Mun SW, Lee YJ, Park JH. Clinical Features and
Extraintestinal Manifestations of Crohn Disease in Children. Pediatr Gastroenterol Hepatol
Nutr. 2016;19(4):236-242. doi:10.5223/pghn.2016.19.4.236
3. Dhaliwal J, Walters TD, Mack DR, et al. Phenotypic Variation in Paediatric
Inflammatory Bowel Disease by Age: A Multicentre Prospective Inception Cohort Study of
the Canadian Children IBD Network. J Crohns Colitis. 2020;14(4):445-454.
doi:10.1093/ecco-jcc/jjz106
4. Benchimol EI, Fortinsky KJ, Gozdyra P, Van den Heuvel M, Van Limbergen J,
Griffiths AM. Epidemiology of pediatric inflammatory bowel disease: a systematic review of
international trends. Inflamm Bowel Dis. 2011;17(1):423-39. doi:10.1002/ibd.21349
5. Ghione S, Sarter H, Fumery M, et al. Dramatic Increase in Incidence of Ulcerative
Colitis and Crohn's Disease (1988-2011): A Population-Based Study of French Adolescents.
Am J Gastroenterol. 2018;113(2):265-272. doi:10.1038/ajg.2017.228
6. Sýkora J, Pomahačová R, Kreslová M, Cvalínová D, Štych P, Schwarz J. Current
global trends in the incidence of pediatric-onset inflammatory bowel disease. World J
Gastroenterol. 2018;24(25):2741-2763. doi:10.3748/wjg.v24.i25.2741
7. Ng SC, Shi HY, Hamidi N, et al. Worldwide incidence and prevalence of
inflammatory bowel disease in the 21st century: a systematic review of population-based
studies. Lancet. 2018;390(10114):2769-2778. doi:10.1016/S0140-6736(17)32448-0
8. Scott FI, Rubin DT, Kugathasan S, et al. Challenges in IBD Research: Pragmatic
Clinical Research. Inflamm Bowel Dis. 2019;25(Supplement_2):S40-S47.
doi:10.1093/ibd/izz085
9. Graham DB, Xavier RJ. Pathway paradigms revealed from the genetics of
inflammatory bowel disease. Nature. 2020;578(7796):527-539. doi:10.1038/s41586-020-
2025-2
10. Santos MPC, Gomes C, Torres J. Familial and ethnic risk in inflammatory bowel
disease. Ann Gastroenterol. 2018;31(1):14-23. doi:10.20524/aog.2017.0208
11. Kelsen J, Baldassano RN. Inflammatory bowel disease: the difference between
children and adults. Inflamm Bowel Dis. 2008;14 Suppl 2:S9-11. doi:10.1002/ibd.20560
58
12. Rosen MJ, Dhawan A, Saeed SA. Inflammatory Bowel Disease in Children and
Adolescents. JAMA Pediatr. 2015;169(11):1053-60. doi:10.1001/jamapediatrics.2015.1982
13. Duricova D, Burisch J, Jess T, Gower-Rousseau C, Lakatos PL, ECCO-EpiCom. Agerelated
differences in presentation and course of inflammatory bowel disease: an update on
the population-based literature. J Crohns Colitis. 2014;8(11):1351-61.
doi:10.1016/j.crohns.2014.05.006
14. Chaparro M, Garre A, Ricart E, et al. Differences between childhood- and adulthoodonset
inflammatory bowel disease: the CAROUSEL study from GETECCU. Aliment
Pharmacol Ther. 2019;49(4):419-428. doi:10.1111/apt.15114
15. Krohn K, Pfeifer M, Manzey P, Koletzko S. [Inflammatory bowel diseases-the
biopsychosocial reality in childhood and adolescence]. Bundesgesundheitsblatt
Gesundheitsforschung Gesundheitsschutz. 2020;63(7):839-845. doi:10.1007/s00103-020-
03166-z
16. Levine A, Koletzko S, Turner D, et al. ESPGHAN revised porto criteria for the
diagnosis of inflammatory bowel disease in children and adolescents. J Pediatr Gastroenterol
Nutr. 2014;58(6):795-806. doi:10.1097/MPG.0000000000000239
17. Ricciuto A, Mack DR, Huynh HQ, et al. Diagnostic Delay Is Associated With
Complicated Disease and Growth Impairment in Paediatric Crohn's Disease. J Crohns Colitis.
2021;15(3):419-431. doi:10.1093/ecco-jcc/jjaa197
18. Schoepfer A, Santos J, Fournier N, et al. Systematic Analysis of the Impact of
Diagnostic Delay on Bowel Damage in Paediatric Versus Adult Onset Crohn's Disease. J
Crohns Colitis. 2019;13(10):1334-1342. doi:10.1093/ecco-jcc/jjz065
19. van Rheenen PF, Aloi M, Assa A, et al. The Medical Management of Paediatric
Crohn's Disease: an ECCO-ESPGHAN Guideline Update. J Crohns Colitis.
2020;doi:10.1093/ecco-jcc/jjaa161
20. Turner D, Ruemmele FM, Orlanski-Meyer E, et al. Management of Paediatric
Ulcerative Colitis, Part 1: Ambulatory Care-An Evidence-based Guideline From European
Crohn's and Colitis Organization and European Society of Paediatric Gastroenterology,
Hepatology and Nutrition. J Pediatr Gastroenterol Nutr. 2018;67(2):257-291.
doi:10.1097/MPG.0000000000002035
21. Turner D, Ruemmele FM, Orlanski-Meyer E, et al. Management of Paediatric
Ulcerative Colitis, Part 2: Acute Severe Colitis-An Evidence-based Consensus Guideline
From the European Crohn's and Colitis Organization and the European Society of Paediatric
59
Gastroenterology, Hepatology and Nutrition. J Pediatr Gastroenterol Nutr. 2018;67(2):292-
310. doi:10.1097/MPG.0000000000002036
22. Ruemmele FM, Veres G, Kolho KL, et al. Consensus guidelines of ECCO/ESPGHAN
on the medical management of pediatric Crohn's disease. J Crohns Colitis. 2014;8(10):1179-
207. doi:10.1016/j.crohns.2014.04.005
23. Guariso G, Gasparetto M. Treating children with inflammatory bowel disease: Current
and new perspectives. World J Gastroenterol. 2017;23(30):5469-5485.
doi:10.3748/wjg.v23.i30.5469
24. Wren AA, Maddux MH. Integrated Multidisciplinary Treatment for Pediatric
Inflammatory Bowel Disease. Children (Basel). 2021;8(2)doi:10.3390/children8020169
25. McCann LJ, Newell SJ. Survey of paediatric complementary and alternative medicine
use in health and chronic illness. Arch Dis Child. 2006;91(2):173-4.
doi:10.1136/adc.2004.052514
26. Singh UP, Singh NP, Busbee B, et al. Alternative medicines as emerging therapies for
inflammatory bowel diseases. Int Rev Immunol. 2012;31(1):66-84.
doi:10.3109/08830185.2011.642909
27. Lin SC, Cheifetz AS. The Use of Complementary and Alternative Medicine in Patients
With Inflammatory Bowel Disease. Gastroenterol Hepatol (N Y). 2018;14(7):415-425.
28. Kelsen JR, Russo P, Sullivan KE. Early-Onset Inflammatory Bowel Disease. Immunol
Allergy Clin North Am. 2019;39(1):63-79. doi:10.1016/j.iac.2018.08.008
29. Lev-Tzion R, Turner D. Is pediatric IBD treatment different than in adults? Minerva
Gastroenterol Dietol. 2012;58(2):137-50.
30. Tontini GE, Vecchi M, Pastorelli L, Neurath MF, Neumann H. Differential diagnosis
in inflammatory bowel disease colitis: state of the art and future perspectives. World J
Gastroenterol. 2015;21(1):21-46. doi:10.3748/wjg.v21.i1.21
31. IBD Working Group of the European Society for Paediatric Gastroenterology HpaN.
Inflammatory bowel disease in children and adolescents: recommendations for diagnosis--the
Porto criteria. J Pediatr Gastroenterol Nutr. Jul 2005;41(1):1-7.
32. Birimberg-Schwartz L, Zucker DM, Akriv A, et al. Development and Validation of
Diagnostic Criteria for IBD Subtypes Including IBD-unclassified in Children: a Multicentre
Study From the Pediatric IBD Porto Group of ESPGHAN. J Crohns Colitis. 2017;11(9):1078-
1084. doi:10.1093/ecco-jcc/jjx053
33. Silverberg MS, Satsangi J, Ahmad T, et al. Toward an integrated clinical, molecular
and serological classification of inflammatory bowel disease: report of a Working Party of the
60
2005 Montreal World Congress of Gastroenterology. Can J Gastroenterol. 2005;19 Suppl
A:5A-36A. doi:10.1155/2005/269076
34. Satsangi J, Silverberg MS, Vermeire S, Colombel JF. The Montreal classification of
inflammatory bowel disease: controversies, consensus, and implications. Gut.
2006;55(6):749-53. doi:10.1136/gut.2005.082909
35. Levine A, Griffiths A, Markowitz J, et al. Pediatric modification of the Montreal
classification for inflammatory bowel disease: the Paris classification. Inflamm Bowel Dis.
2011;17(6):1314-21. doi:10.1002/ibd.21493
36. Assa A, Rinawi F, Shamir R. The Long-Term Predictive Properties of the Paris
Classification in Paediatric Inflammatory Bowel Disease Patients. J Crohns Colitis.
2018;12(1):39-47. doi:10.1093/ecco-jcc/jjx125
37. Arai K. Very Early-Onset Inflammatory Bowel Disease: A Challenging Field for
Pediatric Gastroenterologists. Pediatr Gastroenterol Hepatol Nutr. 2020;23(5):411-422.
doi:10.5223/pghn.2020.23.5.411
38. Uhlig HH, Schwerd T, Koletzko S, et al. The diagnostic approach to monogenic very
early onset inflammatory bowel disease. Gastroenterology. 2014;147(5):990-1007.e3.
doi:10.1053/j.gastro.2014.07.023
39. Uhlig HH, Charbit-Henrion F, Kotlarz D, et al. Clinical Genomics for the Diagnosis of
Monogenic Forms of Inflammatory Bowel Disease: A Position Paper From the Paediatric
IBD Porto Group of European Society of Paediatric Gastroenterology, Hepatology and
Nutrition. J Pediatr Gastroenterol Nutr. 2021;72(3):456-473.
doi:10.1097/MPG.0000000000003017
40. de Lange KM, Moutsianas L, Lee JC, et al. Genome-wide association study implicates
immune activation of multiple integrin genes in inflammatory bowel disease. Nat Genet.
2017;49(2):256-261. doi:10.1038/ng.3760
41. Jezernik G, Mičetić-Turk D, Potočnik U. Molecular Genetic Architecture of
Monogenic Pediatric IBD Differs from Complex Pediatric and Adult IBD. J Pers Med.
2020;10(4)doi:10.3390/jpm10040243
42. Jabandziev P, Hlavackova E, Bily V, et al. Trichohepatoenteric syndrome in a patient
with TTC37 mutations - case report. Gastroent Hepatol. 2020;74(6):481-487.
doi:10.48095/ccgh20201
43. Kaplan GG. The global burden of IBD: from 2015 to 2025. Nat Rev Gastroenterol
Hepatol. 2015;12(12):720-7. doi:10.1038/nrgastro.2015.150
61
44. Kaplan GG, Windsor JW. The four epidemiological stages in the global evolution of
inflammatory bowel disease. Nat Rev Gastroenterol Hepatol. 2021;18(1):56-66.
doi:10.1038/s41575-020-00360-x
45. Bernstein CN, Rawsthorne P, Cheang M, Blanchard JF. A population-based case
control study of potential risk factors for IBD. Am J Gastroenterol. 2006;101(5):993-1002.
doi:10.1111/j.1572-0241.2006.00381.x
46. Rajbhandari R, Blakemore S, Gupta N, et al. Crohn's disease in low and lower-middle
income countries: A scoping review. World J Gastroenterol. 2020;26(43):6891-6908.
doi:10.3748/wjg.v26.i43.6891
47. Kamm MA. Rapid changes in epidemiology of inflammatory bowel disease. Lancet.
2018;390(10114):2741-2742. doi:10.1016/S0140-6736(17)32669-7
48. Coward S, Clement F, Benchimol EI, et al. Past and Future Burden of Inflammatory
Bowel Diseases Based on Modeling of Population-Based Data. Gastroenterology.
2019;156(5):1345-1353.e4. doi:10.1053/j.gastro.2019.01.002
49. Principi M, Labarile N, Bianchi FP, et al. The Cost of Inflammatory Bowel Disease
Management Matches with Clinical Course: A Single Outpatient Centre Analysis. Int J
Environ Res Public Health. 2020;17(12)doi:10.3390/ijerph17124549
50. El-Matary W, Kuenzig ME, Singh H, et al. Disease-Associated Costs in Children With
Inflammatory Bowel Disease: A Systematic Review. Inflamm Bowel Dis. 2020;26(2):206-
215. doi:10.1093/ibd/izz120
51. Eszter Müller K, Laszlo Lakatos P, Papp M, Veres G. Incidence and paris
classification of pediatric inflammatory bowel disease. Gastroenterol Res Pract.
2014;2014:904307. doi:10.1155/2014/904307
52. Collaborators GIBD. The global, regional, and national burden of inflammatory bowel
disease in 195 countries and territories, 1990-2017: a systematic analysis for the Global
Burden of Disease Study 2017. Lancet Gastroenterol Hepatol. 2020;5(1):17-30.
doi:10.1016/S2468-1253(19)30333-4
53. Burisch J, Pedersen N, Čuković-Čavka S, et al. East-West gradient in the incidence of
inflammatory bowel disease in Europe: the ECCO-EpiCom inception cohort. Gut.
2014;63(4):588-97. doi:10.1136/gutjnl-2013-304636
54. Hradský O. Rizikové faktory vzniku a průběhu zánětlivých střevních onemocnění u
dětí. Univerzita Karlova; 2017.
55. Safarpour AR, Mehrabi M, Keshtkar A, Edjtehadi F, Bagheri Lankarani K. Systematic
review and meta-analysis of the incidence and prevalence and 30-year trend of inflammatory
62
bowel diseases in Asia: a study protocol. BMJ Open. 2019;9(11):e031854.
doi:10.1136/bmjopen-2019-031854
56. Jabandziev P, Pinkasova T, Kunovsky L, et al. Regional Incidence of Inflammatory
Bowel Disease in a Czech Pediatric Population: 16 Years of Experience (2002-2017). J
Pediatr Gastroenterol Nutr. 2020;70(5):586-592. doi:10.1097/MPG.0000000000002660
57. Roberts SE, Thorne K, Thapar N, et al. A Systematic Review and Meta-analysis of
Paediatric Inflammatory Bowel Disease Incidence and Prevalence Across Europe. J Crohns
Colitis. 2020;14(8):1119-1148. doi:10.1093/ecco-jcc/jjaa037
58. Pozler O, Maly J, Bonova O, et al. Incidence of Crohn disease in the Czech Republic
in the years 1990 to 2001 and assessment of pediatric population with inflammatory bowel
disease. J Pediatr Gastroenterol Nutr. 2006;42(2):186-9.
doi:10.1097/01.mpg.0000189328.47150.bc
59. Schwarz J, Sýkora J, Cvalínová D, et al. Inflammatory bowel disease incidence in
Czech children: A regional prospective study, 2000-2015. World J Gastroenterol.
2017;23(22):4090-4101. doi:10.3748/wjg.v23.i22.4090
60. Scott FI, Rubin DT, Kugathasan S, et al. Challenges in IBD Research: Pragmatic
Clinical Research. Inflamm Bowel Dis. 2019;25(Suppl 2):S40-S47. doi:10.1093/ibd/izz085
61. Lee SH, Kwon JE, Cho ML. Immunological pathogenesis of inflammatory bowel
disease. Intest Res. 2018;16(1):26-42. doi:10.5217/ir.2018.16.1.26
62. Guan Q. A Comprehensive Review and Update on the Pathogenesis of Inflammatory
Bowel Disease. J Immunol Res. 2019;2019:7247238. doi:10.1155/2019/7247238
63. Ramos GP, Papadakis KA. Mechanisms of Disease: Inflammatory Bowel Diseases.
Mayo Clin Proc. 2019;94(1):155-165. doi:10.1016/j.mayocp.2018.09.013
64. Chichlowski M, Hale LP. Bacterial-mucosal interactions in inflammatory bowel
disease: an alliance gone bad. Am J Physiol Gastrointest Liver Physiol. 2008;295(6):G1139-
49. doi:10.1152/ajpgi.90516.2008
65. Antoni L, Nuding S, Weller D, et al. Human colonic mucus is a reservoir for
antimicrobial peptides. J Crohns Colitis. 2013;7(12):e652-64.
doi:10.1016/j.crohns.2013.05.006
66. Antoni L, Nuding S, Wehkamp J, Stange EF. Intestinal barrier in inflammatory bowel
disease. World J Gastroenterol. 2014;20(5):1165-79. doi:10.3748/wjg.v20.i5.1165
67. Nishida A, Inoue R, Inatomi O, Bamba S, Naito Y, Andoh A. Gut microbiota in the
pathogenesis of inflammatory bowel disease. Clin J Gastroenterol. 2018;11(1):1-10.
doi:10.1007/s12328-017-0813-5
63
68. Zheng D, Liwinski T, Elinav E. Interaction between microbiota and immunity in
health and disease. Cell Res. 2020;30(6):492-506. doi:10.1038/s41422-020-0332-7
69. Capaldo CT, Powell DN, Kalman D. Layered defense: how mucus and tight junctions
seal the intestinal barrier. J Mol Med (Berl). 2017;95(9):927-934. doi:10.1007/s00109-017-
1557-x
70. Okumura R, Takeda K. Roles of intestinal epithelial cells in the maintenance of gut
homeostasis. Exp Mol Med. 2017;49(5):e338. doi:10.1038/emm.2017.20
71. Mann ER, Li X. Intestinal antigen-presenting cells in mucosal immune homeostasis:
crosstalk between dendritic cells, macrophages and B-cells. World J Gastroenterol.
2014;20(29):9653-64. doi:10.3748/wjg.v20.i29.9653
72. Borg-Bartolo SP, Boyapati RK, Satsangi J, Kalla R. Precision medicine in
inflammatory bowel disease: concept, progress and challenges. F1000Res.
2020;9doi:10.12688/f1000research.20928.1
73. Ananthakrishnan AN, Bernstein CN, Iliopoulos D, et al. Environmental triggers in
IBD: a review of progress and evidence. Nat Rev Gastroenterol Hepatol. 2018;15(1):39-49.
doi:10.1038/nrgastro.2017.136
74. Elten M, Benchimol EI, Fell DB, et al. Residential Greenspace in Childhood Reduces
Risk of Pediatric Inflammatory Bowel Disease: A Population-Based Cohort Study. Am J
Gastroenterol. 2021;116(2):347-353. doi:10.14309/ajg.0000000000000990
75. Elten M, Benchimol EI, Fell DB, et al. Ambient air pollution and the risk of pediatriconset
inflammatory bowel disease: A population-based cohort study. Environ Int.
2020;138:105676. doi:10.1016/j.envint.2020.105676
76. Nguyen LH, Örtqvist AK, Cao Y, et al. Antibiotic use and the development of
inflammatory bowel disease: a national case-control study in Sweden. Lancet Gastroenterol
Hepatol. 2020;5(11):986-995. doi:10.1016/S2468-1253(20)30267-3
77. Khalili H, Håkansson N, Chan SS, et al. Adherence to a Mediterranean diet is
associated with a lower risk of later-onset Crohn's disease: results from two large prospective
cohort studies. Gut. 2020;69(9):1637-1644. doi:10.1136/gutjnl-2019-319505
78. Mentella MC, Scaldaferri F, Pizzoferrato M, Gasbarrini A, Miggiano GAD. Nutrition,
IBD and Gut Microbiota: A Review. Nutrients. 2020;12(4)doi:10.3390/nu12040944
79. Piovani D, Danese S, Peyrin-Biroulet L, Nikolopoulos GK, Lytras T, Bonovas S.
Environmental Risk Factors for Inflammatory Bowel Diseases: An Umbrella Review of Metaanalyses.
Gastroenterology. 2019;157(3):647-659.e4. doi:10.1053/j.gastro.2019.04.016
64
80. Abegunde AT, Muhammad BH, Bhatti O, Ali T. Environmental risk factors for
inflammatory bowel diseases: Evidence based literature review. World J Gastroenterol.
2016;22(27):6296-317. doi:10.3748/wjg.v22.i27.6296
81. Olivera P, Danese S, Jay N, Natoli G, Peyrin-Biroulet L. Big data in IBD: a look into
the future. Nat Rev Gastroenterol Hepatol. 2019;16(5):312-321. doi:10.1038/s41575-019-
0102-5
82. Liu JZ, Anderson CA. Genetic studies of Crohn's disease: past, present and future.
Best Pract Res Clin Gastroenterol. 2014;28(3):373-86. doi:10.1016/j.bpg.2014.04.009
83. Liu JZ, van Sommeren S, Huang H, et al. Association analyses identify 38
susceptibility loci for inflammatory bowel disease and highlight shared genetic risk across
populations. Nat Genet. 2015;47(9):979-986. doi:10.1038/ng.3359
84. Hu S, Uniken Venema WT, Westra HJ, et al. Inflammation status modulates the effect
of host genetic variation on intestinal gene expression in inflammatory bowel disease. Nat
Commun. 2021;12(1):1122. doi:10.1038/s41467-021-21458-z
85. Jabandziev P, Bohosova J, Pinkasova T, Kunovsky L, Slaby O, Goel A. The Emerging
Role of Noncoding RNAs in Pediatric Inflammatory Bowel Disease. Inflamm Bowel Dis.
2020;26(7):985-993. doi:10.1093/ibd/izaa009
86. Zhang P, Wu W, Chen Q, Chen M. Non-Coding RNAs and their Integrated Networks.
J Integr Bioinform. 2019;16(3)doi:10.1515/jib-2019-0027
87. Martens-Uzunova ES, Olvedy M, Jenster G. Beyond microRNA--novel RNAs derived
from small non-coding RNA and their implication in cancer. Cancer Lett. 2013;340(2):201-
11. doi:10.1016/j.canlet.2012.11.058
88. Anastasiadou E, Jacob LS, Slack FJ. Non-coding RNA networks in cancer. Nat Rev
Cancer. 2018;18(1):5-18. doi:10.1038/nrc.2017.99
89. Salviano-Silva A, Lobo-Alves SC, Almeida RC, Malheiros D, Petzl-Erler ML.
Besides Pathology: Long Non-Coding RNA in Cell and Tissue Homeostasis. Noncoding
RNA. 2018;4(1)doi:10.3390/ncrna4010003
90. Iborra M, Bernuzzi F, Correale C, et al. Identification of serum and tissue micro-RNA
expression profiles in different stages of inflammatory bowel disease. Clin Exp Immunol.
2013;173(2):250-8. doi:10.1111/cei.12104
91. Wu LY, Ma XP, Shi Y, et al. Alterations in microRNA expression profiles in inflamed
and noninflamed ascending colon mucosae of patients with active Crohn's disease. J
Gastroenterol Hepatol. 2017;32(10):1706-1715. doi:10.1111/jgh.13778
65
92. Zahm AM, Hand NJ, Tsoucas DM, Le Guen CL, Baldassano RN, Friedman JR. Rectal
microRNAs are perturbed in pediatric inflammatory bowel disease of the colon. J Crohns
Colitis. 2014;8(9):1108-17. doi:10.1016/j.crohns.2014.02.012
93. Verdier J, Breunig IR, Ohse MC, et al. Faecal Micro-RNAs in Inflammatory Bowel
Diseases. J Crohns Colitis. 2020;14(1):110-117. doi:10.1093/ecco-jcc/jjz120
94. Dragoni G, Innocenti T, Galli A. Biomarkers of Inflammation in Inflammatory Bowel
Disease: How Long before Abandoning Single-Marker Approaches? Dig Dis.
2021;39(3):190-203. doi:10.1159/000511641
95. Park JH, Peyrin-Biroulet L, Eisenhut M, Shin JI. IBD immunopathogenesis: A
comprehensive review of inflammatory molecules. Autoimmun Rev. 2017;16(4):416-426.
doi:10.1016/j.autrev.2017.02.013
96. Adamcova M, Bajer M, Bajerova K, et al. Czech Working Group for Paediatric
Gastroenterology and Nutrition guidelines for diagnostics and treatment of inflammatory
bowel diseases in children. Ces-slov Pediat. 2012;67(4)(2)
97. Bronsky J, Berankova K, Cerna Z, et al. Czech Working Group for Paediatric
Gastroenterology and Nutrition guidelines for diagnostics and treatment of inflammatory
bowel diseases in children – 1st edition update. Gastroent Hepatol. 2017;71(1):11-18.
doi:10.14735/amgh20171
98. Hyams JS, Ferry GD, Mandel FS, et al. Development and validation of a pediatric
Crohn's disease activity index. J Pediatr Gastroenterol Nutr. May 1991;12(4):439-47.
99. Hyams J, Markowitz J, Otley A, et al. Evaluation of the pediatric crohn disease
activity index: a prospective multicenter experience. J Pediatr Gastroenterol Nutr.
2005;41(4):416-21. doi:10.1097/01.mpg.0000183350.46795.42
100. Turner D, Levine A, Walters TD, et al. Which PCDAI Version Best Reflects Intestinal
Inflammation in Pediatric Crohn Disease? J Pediatr Gastroenterol Nutr. 2017;64(2):254-260.
doi:10.1097/MPG.0000000000001227
101. Turner D, Hyams J, Markowitz J, et al. Appraisal of the pediatric ulcerative colitis
activity index (PUCAI). Inflamm Bowel Dis. 2009;15(8):1218-23. doi:10.1002/ibd.20867
102. Dotson JL, Crandall WV, Zhang P, et al. Feasibility and validity of the pediatric
ulcerative colitis activity index in routine clinical practice. J Pediatr Gastroenterol Nutr. Feb
2015;60(2):200-4. doi:10.1097/MPG.0000000000000568
103. Oliveira SB, Monteiro IM. Diagnosis and management of inflammatory bowel disease
in children. BMJ. 2017;357:j2083. doi:10.1136/bmj.j2083
104. Zbořil V. Idiopatické střevní záněty. Mladá fronta; 2018.
66
105. Greuter T, Vavricka SR. Extraintestinal manifestations in inflammatory bowel disease
- epidemiology, genetics, and pathogenesis. Expert Rev Gastroenterol Hepatol.
2019;13(4):307-317. doi:10.1080/17474124.2019.1574569
106. Yu YR, Rodriguez JR. Clinical presentation of Crohn's, ulcerative colitis, and
indeterminate colitis: Symptoms, extraintestinal manifestations, and disease phenotypes.
Semin Pediatr Surg. 2017;26(6):349-355. doi:10.1053/j.sempedsurg.2017.10.003
107. Jang HJ, Kang B, Choe BH. The difference in extraintestinal manifestations of
inflammatory bowel disease for children and adults. Transl Pediatr. J2019;8(1):4-15.
doi:10.21037/tp.2019.01.06
108. Aloi M, D'Arcangelo G, Pofi F, et al. Presenting features and disease course of
pediatric ulcerative colitis. J Crohns Colitis. 2013;7(11):e509-15.
doi:10.1016/j.crohns.2013.03.007
109. Birimberg-Schwartz L, Wilson DC, Kolho KL, et al. pANCA and ASCA in Children
with IBD-Unclassified, Crohn's Colitis, and Ulcerative Colitis-A Longitudinal Report from
the IBD Porto Group of ESPGHAN. Inflamm Bowel Dis. 2016;22(8):1908-14.
doi:10.1097/MIB.0000000000000784
110. Ashton JJ, Borca F, Mossotto E, Phan HTT, Ennis S, Beattie RM. Analysis and
Hierarchical Clustering of Blood Results Before Diagnosis in Pediatric Inflammatory Bowel
Disease. Inflamm Bowel Dis. 2020;26(3):469-475. doi:10.1093/ibd/izy369
111. Ricciuto A, Griffiths AM. Clinical value of fecal calprotectin. Crit Rev Clin Lab Sci.
2019;56(5):307-320. doi:10.1080/10408363.2019.1619159
112. Walker GJ, Chanchlani N, Thomas A, et al. Primary care faecal calprotectin testing in
children with suspected inflammatory bowel disease: a diagnostic accuracy study. Arch Dis
Child. 2020;105(10):957-963. doi:10.1136/archdischild-2019-317823
113. D'Amico F, Rubin DT, Kotze PG, et al. International consensus on methodological
issues in standardization of fecal calprotectin measurement in inflammatory bowel diseases.
United European Gastroenterol J. 2021;9(4):451-460. doi:10.1002/ueg2.12069
114. D'Amico F, Nancey S, Danese S, Peyrin-Biroulet L. A Practical Guide for Faecal
Calprotectin Measurement: Myths and Realities. J Crohns Colitis. 2021;15(1):152-161.
doi:10.1093/ecco-jcc/jjaa093
115. Koninckx CR, Donat E, Benninga MA, et al. The Use of Fecal Calprotectin Testing in
Paediatric Disorders: A Position Paper of the European Society for Paediatric
Gastroenterology and Nutrition Gastroenterology Committee. J Pediatr Gastroenterol Nutr.
2021;72(4):617-640. doi:10.1097/MPG.0000000000003046
67
116. Ricciuto A, Aardoom M, Orlanski-Meyer E, et al. Predicting Outcomes in Pediatric
Crohn's Disease for Management Optimization: Systematic Review and Consensus
Statements From the Pediatric Inflammatory Bowel Disease-Ahead Program.
Gastroenterology. 2021;160(1):403-436.e26. doi:10.1053/j.gastro.2020.07.065
117. Orlanski-Meyer E, Aardoom M, Ricciuto A, et al. Predicting Outcomes in Pediatric
Ulcerative Colitis for Management Optimization: Systematic Review and Consensus
Statements From the Pediatric Inflammatory Bowel Disease-Ahead Program.
Gastroenterology. 2021;160(1):378-402.e22. doi:10.1053/j.gastro.2020.07.066
118. Spiceland CM, Lodhia N. Endoscopy in inflammatory bowel disease: Role in
diagnosis, management, and treatment. World J Gastroenterol. 2018;24(35):4014-4020.
doi:10.3748/wjg.v24.i35.4014
119. Bharadwaj S, Narula N, Tandon P, Yaghoobi M. Role of endoscopy in inflammatory
bowel disease. Gastroenterol Rep (Oxf). 2018;6(2):75-82. doi:10.1093/gastro/goy006
120. Limdi JK, Picco M, Farraye FA. A review of endoscopic scoring systems and their
importance in a treat-to-target approach in inflammatory bowel disease (with videos).
Gastrointest Endosc. 2020;91(4):733-745. doi:10.1016/j.gie.2019.11.032
121. Daperno M, D'Haens G, Van Assche G, et al. Development and validation of a new,
simplified endoscopic activity score for Crohn's disease: the SES-CD. Gastrointest Endosc.
2004;60(4):505-12. doi:10.1016/s0016-5107(04)01878-4
122. Travis SP, Schnell D, Krzeski P, et al. Developing an instrument to assess the
endoscopic severity of ulcerative colitis: the Ulcerative Colitis Endoscopic Index of Severity
(UCEIS). Gut. 2012;61(4):535-42. doi:10.1136/gutjnl-2011-300486
123. Rutgeerts P, Geboes K, Vantrappen G, Beyls J, Kerremans R, Hiele M. Predictability
of the postoperative course of Crohn's disease. Gastroenterology. 1990;99(4):956-63.
doi:10.1016/0016-5085(90)90613-6
124. Thomson M, Tringali A, Dumonceau JM, et al. Paediatric Gastrointestinal Endoscopy:
European Society for Paediatric Gastroenterology Hepatology and Nutrition and European
Society of Gastrointestinal Endoscopy Guidelines. J Pediatr Gastroenterol Nutr.
2017;64(1):133-153. doi:10.1097/MPG.0000000000001408
125. Oliva S, Thomson M, de Ridder L, et al. Endoscopy in Pediatric Inflammatory Bowel
Disease: A Position Paper on Behalf of the Porto IBD Group of the European Society for
Pediatric Gastroenterology, Hepatology and Nutrition. J Pediatr Gastroenterol Nutr.
2018;67(3):414-430. doi:10.1097/MPG.0000000000002092
68
126. Broekaert I, Tzivinikos C, Narula P, et al. European Society for Paediatric
Gastroenterology, Hepatology and Nutrition Position Paper on Training in Paediatric
Endoscopy. J Pediatr Gastroenterol Nutr. 2020;70(1):127-140.
doi:10.1097/MPG.0000000000002496
127. Van de Vijver E, Heida A, Ioannou S, et al. Test Strategies to Predict Inflammatory
Bowel Disease Among Children With Nonbloody Diarrhea. Pediatrics.
2020;146(2)doi:10.1542/peds.2019-2235
128. Sahn B, De Matos V, Stein R, et al. Histological features of ileitis differentiating
pediatric Crohn disease from ulcerative colitis with backwash ileitis. Dig Liver Dis.
2018;50(2):147-153. doi:10.1016/j.dld.2017.10.006
129. Glass J, Alcalá HE, Tobin M. The Value of Obtaining Colonic Mucosal Biopsies of
Grossly Normal Tissue in Pediatric Patients. J Pediatr Gastroenterol Nutr. 2021;72(5):677-
682. doi:10.1097/MPG.0000000000003038
130. Conrad MA, Carreon CK, Dawany N, Russo P, Kelsen JR. Distinct Histopathological
Features at Diagnosis of Very Early Onset Inflammatory Bowel Disease. J Crohns Colitis.
2019;13(5):615-625. doi:10.1093/ecco-jcc/jjy212
131. Magro F, Langner C, Driessen A, et al. European consensus on the histopathology of
inflammatory bowel disease. J Crohns Colitis. 2013;7(10):827-51.
doi:10.1016/j.crohns.2013.06.001
132. Engel PJH, Fiehn AK, Munck LK, Kristensson M. The subtypes of microscopic colitis
from a pathologist's perspective: past, present and future. Ann Transl Med. 2018;6(3):69.
doi:10.21037/atm.2017.03.16
133. Schreiber-Dietrich D, Chiorean L, Cui XW, et al. Particularities of Crohn's disease in
pediatric patients: current status and perspectives regarding imaging modalities. Expert Rev
Gastroenterol Hepatol. 2015;9(10):1313-25. doi:10.1586/17474124.2015.1083420
134. van Wassenaer EA, de Voogd FAE, van Rijn RR, et al. Diagnostic Accuracy of
Transabdominal Ultrasound in Detecting Intestinal Inflammation in Paediatric IBD Patients-a
Systematic Review. J Crohns Colitis. 2019;13(12):1501-1509. doi:10.1093/ecco-jcc/jjz085
135. Duvoisin G, Lopez RN, Day AS, Lemberg DA, Gearry RB, Leach ST. Novel
Biomarkers and the Future Potential of Biomarkers in Inflammatory Bowel Disease.
Mediators Inflamm. 2017;2017:1936315. doi:10.1155/2017/1936315
136. Torres J, Petralia F, Sato T, et al. Serum Biomarkers Identify Patients Who Will
Develop Inflammatory Bowel Diseases Up to 5 Years Before Diagnosis. Gastroenterology.
2020;159(1):96-104. doi:10.1053/j.gastro.2020.03.007
69
137. Pinto-Lopes P, Afonso J, Pinto-Lopes R, et al. Serum Dipeptidyl Peptidase 4: A
Predictor of Disease Activity and Prognosis in Inflammatory Bowel Disease. Inflamm Bowel
Dis. 2020;26(11):1707-1719. doi:10.1093/ibd/izz319
138. Pinto-Lopes P, Melo F, Afonso J, et al. Fecal Dipeptidyl Peptidase-4: An Emergent
Biomarker in Inflammatory Bowel Disease. Clin Transl Gastroenterol. 2021;12(3):e00320.
doi:10.14309/ctg.0000000000000320
139. Perry C, Kapur N, Barrett TA. DPP-4 as a Novel Biomarker for Inflammatory Bowel
Disease: Is It Ready for Clinical Use? Inflamm Bowel Dis. 2020;26(11):1720-1721.
doi:10.1093/ibd/izz320
140. Jabandziev P, Kakisaka T, Bohosova J, et al. MicroRNAs in Colon Tissue of Pediatric
Ulcerative Pancolitis Patients Allow Detection and Prognostic Stratification. J Clin Med.
2021;10(6). doi:10.3390/jcm10061325
141. Chen P, Zhou G, Lin J, et al. Serum Biomarkers for Inflammatory Bowel Disease.
Front Med (Lausanne). 2020;7:123. doi:10.3389/fmed.2020.00123
142. Leach ST, Day AS, Messenger R, et al. Fecal Markers of Inflammation and Disease
Activity in Pediatric Crohn Disease: Results from the ImageKids Study. J Pediatr
Gastroenterol Nutr. 2020;70(5):580-585. doi:10.1097/MPG.0000000000002615
143. Heida A, Van de Vijver E, van Ravenzwaaij D, et al. Predicting inflammatory bowel
disease in children with abdominal pain and diarrhoea: calgranulin-C versus calprotectin stool
tests. Arch Dis Child. 2018;103(6):565-571. doi:10.1136/archdischild-2017-314081
144. Naganuma M, Hosoe N, Kanai T, Ogata H. Recent trends in diagnostic techniques for
inflammatory bowel disease. Korean J Intern Med. 2015;30(3):271-8.
doi:10.3904/kjim.2015.30.3.271
145. Buchner AM. Confocal Laser Endomicroscopy in the Evaluation of Inflammatory
Bowel Disease. Inflamm Bowel Dis. 2019;25(8):1302-1312. doi:10.1093/ibd/izz021
146. Kunovský L, Kala Z, Kroupa R, et al. Confocal laser endomicroscopy in the
diagnostics of esophageal diseases: a pilot study. Vnitr Lek. 2020;66(5):62-68.
147. Goodwin S, McPherson JD, McCombie WR. Coming of age: ten years of nextgeneration
sequencing technologies. Nat Rev Genet. 2016;17(6):333-51.
doi:10.1038/nrg.2016.49
148. Slatko BE, Gardner AF, Ausubel FM. Overview of Next-Generation Sequencing
Technologies. Curr Protoc Mol Biol. 2018;122(1):e59. doi:10.1002/cpmb.59
149. Slaba K, Noskova H, Vesela P, et al. Novel Splicing Variant in the. Front Genet.
2020;11:561054. doi:10.3389/fgene.2020.561054
70
150. Siegel CA, Bernstein CN. Identifying Patients With Inflammatory Bowel Diseases
at High vs Low Risk of Complications. Clin Gastroenterol Hepatol. 2020;18(6):1261-1267.
doi:10.1016/j.cgh.2019.11.034
151. Naviglio S, Lacorte D, Lucafò M, et al. Causes of Treatment Failure in Children With
Inflammatory Bowel Disease Treated With Infliximab: A Pharmacokinetic Study. J Pediatr
Gastroenterol Nutr. 2019;68(1):37-44. doi:10.1097/MPG.0000000000002112
152. Gecse KB, Vermeire S. Differential diagnosis of inflammatory bowel disease:
imitations and complications. Lancet Gastroenterol Hepatol. 2018;3(9):644-653.
doi:10.1016/S2468-1253(18)30159-6
153. Kliegman R. Nelson Textbook of Pediatrics. vol 21. Elsevier; 2020.
154. Hamdeh S, Micic D, Hanauer S. Drug-Induced Colitis. Clin Gastroenterol Hepatol.
2020; 30:S1542-3565(20)30614-5. doi:10.1016/j.cgh.2020.04.069
155. Nambu R, Muise AM. Advanced Understanding of Monogenic Inflammatory Bowel
Disease. Front Pediatr. 2020;8:618918. doi:10.3389/fped.2020.618918
156. Kelsen JR, Sullivan KE, Rabizadeh S, et al. NASPGHAN Position Paper on The
Evaluation and Management for Patients with Very Early-Onset Inflammatory Bowel Disease
(VEO-IBD). J Pediatr Gastroenterol Nutr. 2019;doi:10.1097/MPG.0000000000002567
157. Bousfiha A, Jeddane L, Picard C, et al. Human Inborn Errors of Immunity: 2019
Update of the IUIS Phenotypical Classification. J Clin Immunol. 2020;40(1):66-81.
doi:10.1007/s10875-020-00758-x
158. Shim JO. Recent Advance in Very Early Onset Inflammatory Bowel Disease. Pediatr
Gastroenterol Hepatol Nutr. 2019;22(1):41-49. doi:10.5223/pghn.2019.22.1.41
159. Nambu R, Warner N, Mulder DJ, et al. A Systematic Review of Monogenic
Inflammatory Bowel Disease. Clin Gastroenterol Hepatol. 2021; 18:S1542-3565(21)003311.
doi:10.1016/j.cgh.2021.03.021
160. Chang IJ, He M, Lam CT. Congenital disorders of glycosylation. Ann Transl Med.
2018;6(24):477. doi:10.21037/atm.2018.10.45
161. Francisco R, Marques-da-Silva D, Brasil S, et al. The challenge of CDG diagnosis.
Mol Genet Metab. 2019;126(1):1-5. doi:10.1016/j.ymgme.2018.11.003
162. Bogdańska A, Lipiński P, Szymańska-Rożek P, et al. Clinical, biochemical and
molecular phenotype of congenital disorders of glycosylation: long-term follow-up. Orphanet
J Rare Dis. 2021;16(1):17. doi:10.1186/s13023-020-01657-5
71
163. Witters P, Honzik T, Bauchart E, et al. Long-term follow-up in PMM2-CDG: are we
ready to start treatment trials? Genet Med. 2019;21(5):1181-1188. doi:10.1038/s41436-018-
0301-4
164. Schiff M, Roda C, Monin ML, et al. Clinical, laboratory and molecular findings and
long-term follow-up data in 96 French patients with PMM2-CDG (phosphomannomutase 2congenital
disorder of glycosylation) and review of the literature. J Med Genet.
2017;54(12):843-851. doi:10.1136/jmedgenet-2017-104903
165. Francisco R, Pascoal C, Marques-da-Silva D, et al. New Insights into Immunological
Involvement in Congenital Disorders of Glycosylation (CDG) from a People-Centric
Approach. J Clin Med. 2020;9(7)doi:10.3390/jcm9072092
166. Narumi S, Amano N, Ishii T, et al. SAMD9 mutations cause a novel multisystem
disorder, MIRAGE syndrome, and are associated with loss of chromosome 7. Nat Genet.
2016;48(7):792-7. doi:10.1038/ng.3569
167. Shima H, Hayashi M, Tachibana T, et al. MIRAGE syndrome is a rare cause of 46,XY
DSD born SGA without adrenal insufficiency. PLoS One. 2018;13(11):e0206184.
doi:10.1371/journal.pone.0206184
168. Perisa MP, Rose MJ, Varga E, Kamboj MK, Spencer JD, Bajwa RPS. A novel
SAMD9 variant identified in patient with MIRAGE syndrome: Further defining syndromic
phenotype and review of previous cases. Pediatr Blood Cancer. 2019;66(7):e27726.
doi:10.1002/pbc.27726
169. Onuma S, Wada T, Araki R, et al. MIRAGE syndrome caused by a novel missense
variant (p.Ala1479Ser) in the. Hum Genome Var. 2020;7:4. doi:10.1038/s41439-020-0091-5
170. Ishiwa S, Kamei K, Tanase-Nakao K, et al. A girl with MIRAGE syndrome who
developed steroid-resistant nephrotic syndrome: a case report. BMC Nephrol.
2020;21(1):340. doi:10.1186/s12882-020-02011-4
171. Formankova R, Kanderova V, Rackova M, et al. Novel SAMD9 Mutation in a Patient
With Immunodeficiency, Neutropenia, Impaired Anti-CMV Response, and Severe
Gastrointestinal Involvement. Front Immunol. 2019;10:2194. doi:10.3389/fimmu.2019.02194
172. Furuta GT, Katzka DA. Eosinophilic Esophagitis. N Engl J Med. Oct
2015;373(17):1640-8. doi:10.1056/NEJMra1502863
173. Zhang M, Li Y. Eosinophilic gastroenteritis: A state-of-the-art review. J Gastroenterol
Hepatol. 2017;32(1):64-72. doi:10.1111/jgh.13463
72
174. Hlouskova E, Bajerova K, Pecl J, Jabandziev P, Jezova M, Tuma J. Eosinophilic
enteritis - case report of a rare manifestation and review of updates. Gastroent Hepatol.
2020;74(6):492-496. doi:10.48095/ccgh2020492
175. Matsushita T, Maruyama R, Ishikawa N, et al. The number and distribution of
eosinophils in the adult human gastrointestinal tract: a study and comparison of racial and
environmental factors. Am J Surg Pathol. 2015;39(4):521-7.
doi:10.1097/PAS.0000000000000370
176. Mehta P, Furuta GT. Eosinophils in Gastrointestinal Disorders: Eosinophilic
Gastrointestinal Diseases, Celiac Disease, Inflammatory Bowel Diseases, and Parasitic
Infections. Immunol Allergy Clin North Am. 2015;35(3):413-37.
doi:10.1016/j.iac.2015.04.003
177. Pecl J, Karaskova E, Kunovsky L, et al. Eosinophilic esophagitis - 10 years of
experience in five Czech pediatric endoscopy centers. Gastroent Hepatol. 2020;74(6):469-
480. doi:10.48095/ccgh2020469
178. Castellaneta SP, Afzal NA, Greenberg M, et al. Diagnostic role of upper
gastrointestinal endoscopy in pediatric inflammatory bowel disease. J Pediatr Gastroenterol
Nutr. 2004;39(3):257-61. doi:10.1097/00005176-200409000-00006
179. Abuquteish D, Putra J. Upper gastrointestinal tract involvement of pediatric
inflammatory bowel disease: A pathological review. World J Gastroenterol.
2019;25(16):1928-1935. doi:10.3748/wjg.v25.i16.1928
180. Galbraith JC, Shafran SD. Herpes simplex esophagitis in the immunocompetent
patient: report of four cases and review. Clin Infect Dis. 1992;14(4):894-901.
doi:10.1093/clinids/14.4.894
181. Jabandziev P, Jouza M, Pecl J, et al. Herpetic esophagitis in a 7-year-old
immunocompetent patient. Gastroent Hepatol. 2020;74(3):233-237.
doi:10.14735/amgh2020233
182. Phadke VK, Friedman-Moraco RJ, Quigley BC, Farris AB, Norvell JP. Concomitant
herpes simplex virus colitis and hepatitis in a man with ulcerative colitis: Case report and
review of the literature. Medicine (Baltimore). 2016;95(42):e5082.
doi:10.1097/MD.0000000000005082
183. Breton J, Kastl A, Conrad MA, Baldassano RN. Positioning Biologic Therapies in the
Management of Pediatric Inflammatory Bowel Disease. Gastroenterol Hepatol (N Y).
2020;16(8):400-414.
73
184. Atreya R, Neurath MF, Siegmund B. Personalizing Treatment in IBD: Hype or Reality
in 2020? Can We Predict Response to Anti-TNF? Front Med (Lausanne). 2020;7:517.
doi:10.3389/fmed.2020.00517
185. Claytor JD, El-Nachef N. Fecal microbial transplant for inflammatory bowel disease.
Curr Opin Clin Nutr Metab Care. 2020;23(5):355-360.
doi:10.1097/MCO.0000000000000676
186. Selset Aandahl G, Jacobsen CD, Rode L, Rathe Oedegaard E. Preliminary experience
with plasma exchange in patients with ulcerative colitis. Transfus Sci. 2000;22(3):155-60.
doi:10.1016/s0955-3886(00)00039-4
187. Ciccocioppo R, Baumgart DC, Dos Santos CC, Galipeau J, Klersy C, Orlando G.
Perspectives of the International Society for Cell & Gene Therapy Gastrointestinal Scientific
Committee on the Intravenous Use of Mesenchymal Stromal Cells in Inflammatory Bowel
Disease (PeMeGi). Cytotherapy. 2019;21(8):824-839. doi:10.1016/j.jcyt.2019.05.003
188. Langhorst J, Wulfert H, Lauche R, et al. Systematic review of complementary and
alternative medicine treatments in inflammatory bowel diseases. J Crohns Colitis.
2015;9(1):86-106. doi:10.1093/ecco-jcc/jju007
189. Antonioli L, Fornai M, Romano B, Pellegrini C, Blandizzi C. Editorial: IBD
Management-Novel Targets and Therapeutic Perspectives. Front Pharmacol. 2020;11:448.
doi:10.3389/fphar.2020.00448
190. Ungaro RC, Aggarwal S, Topaloglu O, Lee WJ, Clark R, Colombel JF. Systematic
review and meta-analysis: efficacy and safety of early biologic treatment in adult and
paediatric patients with Crohn's disease. Aliment Pharmacol Ther. 2020;51(9):831-842.
doi:10.1111/apt.15685
191. Na SY, Moon W. Perspectives on Current and Novel Treatments for Inflammatory
Bowel Disease. Gut Liver. 2019;13(6):604-616. doi:10.5009/gnl19019
192. Olbjørn C, Rove JB, Jahnsen J. Combination of Biological Agents in Moderate to
Severe Pediatric Inflammatory Bowel Disease: A Case Series and Review of the Literature.
Paediatr Drugs. 2020;22(4):409-416. doi:10.1007/s40272-020-00396-1
193. Verburgt CM, Ghiboub M, Benninga MA, de Jonge WJ, Van Limbergen JE.
Nutritional Therapy Strategies in Pediatric Crohn's Disease. Nutrients.
2021;13(1)doi:10.3390/nu13010212
194. Levine A, Wine E, Assa A, et al. Crohn's Disease Exclusion Diet Plus Partial Enteral
Nutrition Induces Sustained Remission in a Randomized Controlled Trial. Gastroenterology.
2019;157(2):440-450.e8. doi:10.1053/j.gastro.2019.04.021
74
195. Sigall Boneh R, Sarbagili Shabat C, Yanai H, et al. Dietary Therapy With the Crohn's
Disease Exclusion Diet is a Successful Strategy for Induction of Remission in Children and
Adults Failing Biological Therapy. J Crohns Colitis. 2017;11(10):1205-1212.
doi:10.1093/ecco-jcc/jjx071
196. Zhan YL, Zhan YA, Dai SX. Is a low FODMAP diet beneficial for patients with
inflammatory bowel disease? A meta-analysis and systematic review. Clin Nutr.
2018;37(1):123-129. doi:10.1016/j.clnu.2017.05.019
197. Vrdoljak J, Vilović M, Živković PM, et al. Mediterranean Diet Adherence and Dietary
Attitudes in Patients with Inflammatory Bowel Disease. Nutrients.
2020;12(11)doi:10.3390/nu12113429
198. Strisciuglio C, Cenni S, Serra MR, et al. Effectiveness of Mediterranean Diet's
Adherence in children with Inflammatory Bowel Diseases. Nutrients.
2020;12(10)doi:10.3390/nu12103206
199. Cucinotta U, Romano C, Dipasquale V. Diet and Nutrition in Pediatric Inflammatory
Bowel Diseases. Nutrients. 2021;13(2)doi:10.3390/nu13020655
200. Bessissow T, Reinglas J, Aruljothy A, Lakatos PL, Van Assche G. Endoscopic
management of Crohn's strictures. World J Gastroenterol. 2018;24(17):1859-1867.
doi:10.3748/wjg.v24.i17.1859
201. Kelay A, Tullie L, Stanton M. Surgery and paediatric inflammatory bowel disease.
Transl Pediatr. 2019;8(5):436-448. doi:10.21037/tp.2019.09.01
202. Amil-Dias J, Kolacek S, Turner D, et al. Surgical Management of Crohn Disease in
Children: Guidelines From the Paediatric IBD Porto Group of ESPGHAN. J Pediatr
Gastroenterol Nutr. 2017;64(5):818-835. doi:10.1097/MPG.0000000000001562
203. Forsdick VK, Tan Tanny SP, King SK. Medical and surgical management of pediatric
perianal crohn's disease: A systematic review. J Pediatr Surg. 2019;54(12):2554-2558.
doi:10.1016/j.jpedsurg.2019.08.036
204. Mutanen A, Pakarinen MP. Perianal Crohn's Disease in Children and Adolescents. Eur
J Pediatr Surg. 2020;30(5):395-400. doi:10.1055/s-0040-1716724
205. Meima-van Praag EM, Buskens CJ, Hompes R, Bemelman WA. Surgical management
of Crohn's disease: a state of the art review. Int J Colorectal Dis. 2021;36(6):1133-1145.
doi:10.1007/s00384-021-03857-2
206. Ashton JJ, Borca F, Mossotto E, et al. Increased prevalence of anti-TNF therapy in
paediatric inflammatory bowel disease is associated with a decline in surgical resections
during childhood. Aliment Pharmacol Ther. 2019;49(4):398-407. doi:10.1111/apt.15094
75
207. Poredska K, Kunovsky L, Marek F, et al. The Influence of Microscopic Inflammation
at Resection Margins on Early Postoperative Endoscopic Recurrence After Ileocaecal
Resection for Crohn's Disease. J Crohns Colitis. 2020;14(3):361-368. doi:10.1093/ecco-
jcc/jjz153
208. Marteau P, Laharie D, Colombel JF, et al. Interobserver Variation Study of the
Rutgeerts Score to Assess Endoscopic Recurrence after Surgery for Crohn's Disease. J
Crohns Colitis. 2016;10(9):1001-5. doi:10.1093/ecco-jcc/jjw082
209. Tandon P, Malhi G, Abdali D, et al. Active Margins, Plexitis, and Granulomas
Increase Postoperative Crohn's Recurrence: Systematic Review and Meta-analysis. Clin
Gastroenterol Hepatol. 2021;19(3):451-462. doi:10.1016/j.cgh.2020.08.014
210. Kim S. Surgery in Pediatric Crohn's Disease: Indications, Timing and Post-Operative
Management. Pediatr Gastroenterol Hepatol Nutr. 2017;20(1):14-21.
doi:10.5223/pghn.2017.20.1.14
211. Adler J, Dong S, Eder SJ, Dombkowski KJ, System IPILH. Perianal Crohn Disease in
a Large Multicenter Pediatric Collaborative. J Pediatr Gastroenterol Nutr. 2017;64(5):e117e124.
doi:10.1097/MPG.0000000000001447
212. Rowe W. Complications of Inflammatory Bowel Disease.
https://emedicine.medscape.com/article/1918545-overview#a1
213. Adler J, Jary HK, Eder SJ, et al. Identifying perianal fistula complications in pediatric
patients with Crohn's disease using administrative claims. PLoS One. 2019;14(8):e0219893.
doi:10.1371/journal.pone.0219893
214. Lee T, Kamm MA, Bell S, et al. Long-term outcomes of perianal fistulizing Crohn's
disease in the biologic era. JGH Open. 2021;5(2):235-241. doi:10.1002/jgh3.12475
215. Benchimol EI, Turner D, Mann EH, et al. Toxic megacolon in children with
inflammatory bowel disease: clinical and radiographic characteristics. Am J Gastroenterol.
2008;103(6):1524-31. doi:10.1111/j.1572-0241.2008.01807.x
216. Desai J, Elnaggar M, Hanfy AA, Doshi R. Toxic Megacolon: Background,
Pathophysiology, Management Challenges and Solutions. Clin Exp Gastroenterol.
2020;13:203-210. doi:10.2147/CEG.S200760
217. Ricciuto A, Hansen BE, Ngo B, et al. Primary Sclerosing Cholangitis in Children With
Inflammatory Bowel Diseases Is Associated With Milder Clinical Activity But More Frequent
Subclinical Inflammation and Growth Impairment. Clin Gastroenterol Hepatol.
2020;18(7):1509-1517.e7. doi:10.1016/j.cgh.2019.08.048
76
218. Lazzerini M, Bramuzzo M, Ventura A. Association between orofacial granulomatosis
and Crohn's disease in children: systematic review. World J Gastroenterol. 2014;20(23):7497-
504. doi:10.3748/wjg.v20.i23.7497
219. Gavioli CFB, Florezi GP, Dabronzo MLD, Jiménez MR, Nico MMS, Lourenço SV.
Orofacial Granulomatosis and Crohn Disease: Coincidence or Pattern? A Systematic Review.
Dermatology. 2021:1-6. doi:10.1159/000513446
220. Kucharska M, Daniluk U, Kwiatek-Średzińska KA, et al. Hepatobiliary manifestations
of inflammatory bowel disease in children. Clin Exp Hepatol. 2019;5(3):203-209.
doi:10.5114/ceh.2019.87632
221. Olén O, Askling J, Sachs MC, et al. Childhood onset inflammatory bowel disease and
risk of cancer: a Swedish nationwide cohort study 1964-2014. BMJ. 2017;358:j3951.
doi:10.1136/bmj.j3951
222. Ishige T. Growth failure in pediatric onset inflammatory bowel disease: mechanisms,
epidemiology, and management. Transl Pediatr. 2019;8(1):16-22.
doi:10.21037/tp.2018.12.04
223. Pappa H, Thayu M, Sylvester F, Leonard M, Zemel B, Gordon C. Skeletal health of
children and adolescents with inflammatory bowel disease. J Pediatr Gastroenterol Nutr.
2011;53(1):11-25. doi:10.1097/MPG.0b013e31821988a3
224. Yang HR. Updates on bone health in children with gastrointestinal diseases. Ann
Pediatr Endocrinol Metab. Mar 2020;25(1):10-14. doi:10.6065/apem.2020.25.1.10
225. Qualter P, Rouncefield-Swales A, Bray L, et al. Depression, anxiety, and loneliness
among adolescents and young adults with IBD in the UK: the role of disease severity, age of
onset, and embarrassment of the condition. Qual Life Res. 2021;30(2):497-506.
doi:10.1007/s11136-020-02653-9
226. Ossum AM, Palm Ø, Lunder AK, et al. Ankylosing Spondylitis and Axial
Spondyloarthritis in Patients With Long-term Inflammatory Bowel Disease: Results From 20
Years of Follow-up in the IBSEN Study. J Crohns Colitis. 2018;12(1):96-104.
doi:10.1093/ecco-jcc/jjx126
227. Diaconescu S, Strat S, Balan GG, et al. Dermatological Manifestations in Pediatric
Inflammatory Bowel Disease. Medicina (Kaunas). 2020;56(9)doi:10.3390/medicina56090425
228. Ottaviano G, Salvatore S, Salvatoni A, Martelossi S, Ventura A, Naviglio S. Ocular
Manifestations of Paediatric Inflammatory Bowel Disease: A Systematic Review and Metaanalysis.
J Crohns Colitis. 2018;12(7):870-879. doi:10.1093/ecco-jcc/jjy029
77
229. Bianchi L, Gaiani F, Bizzarri B, et al. Renal lithiasis and inflammatory bowel diseases,
an update on pediatric population. Acta Biomed. 2018;89(9-S):76-80.
doi:10.23750/abm.v89i9-S.7908
230. Goyal A, Zheng Y, Albenberg LG, et al. Anemia in Children With Inflammatory
Bowel Disease: A Position Paper by the IBD Committee of the North American Society of
Pediatric Gastroenterology, Hepatology and Nutrition. J Pediatr Gastroenterol Nutr.
2020;71(4):563-582. doi:10.1097/MPG.0000000000002885
231. McKie K, McLoughlin RJ, Hirsh MP, Cleary MA, Aidlen JT. Risk Factors for Venous
Thromboembolism in Children and Young Adults With Inflammatory Bowel Disease. J Surg
Res. 2019;243:173-179. doi:10.1016/j.jss.2019.04.087
232. Alvisi P, Dipasquale V, Barabino A, et al. Infections and malignancies risks related to
TNF-α-blocking agents in pediatric inflammatory bowel diseases. Expert Rev Gastroenterol
Hepatol. 2019;13(10):957-961. doi:10.1080/17474124.2019.1663173
233. Dipasquale V, Romano C. Pharmacological treatments and infectious diseases in
pediatric inflammatory bowel disease. Expert Rev Gastroenterol Hepatol. 2018;12(3):237-
247. doi:10.1080/17474124.2018.1391091
234. Cavalcante SS, Mota E, Silva LR, Teixeira LF, Cavalcante LB. Risk factors for
developing nosocomial infections among pediatric patients. Pediatr Infect Dis J.
2006;25(5):438-45. doi:10.1097/01.inf.0000217377.54597.92
235. Holmer A, Singh S. Overall and comparative safety of biologic and
immunosuppressive therapy in inflammatory bowel diseases. Expert Rev Clin Immunol.
2019;15(9):969-979. doi:10.1080/1744666X.2019.1646127
236. Rodríguez-Acelas AL, de Abreu Almeida M, Engelman B, Cañon-Montañez W. Risk
factors for health care-associated infection in hospitalized adults: Systematic review and
meta-analysis. Am J Infect Control. 2017;45(12):e149-e156. doi:10.1016/j.ajic.2017.08.016
237. Singh S, Facciorusso A, Dulai PS, Jairath V, Sandborn WJ. Comparative Risk of
Serious Infections With Biologic and/or Immunosuppressive Therapy in Patients With
Inflammatory Bowel Diseases: A Systematic Review and Meta-Analysis. Clin Gastroenterol
Hepatol. 2020;18(1):69-81.e3. doi:10.1016/j.cgh.2019.02.044
238. Chicco D, Jurman G. Survival prediction of patients with sepsis from age, sex, and
septic episode number alone. Sci Rep. 2020;10(1):17156. doi:10.1038/s41598-020-73558-3
239. Font MD, Thyagarajan B, Khanna AK. Sepsis and Septic Shock - Basics of diagnosis,
pathophysiology and clinical decision making. Med Clin North Am. 2020;104(4):573-585.
doi:10.1016/j.mcna.2020.02.011
78
240. Singer M, Deutschman CS, Seymour CW, et al. The Third International Consensus
Definitions for Sepsis and Septic Shock (Sepsis-3). JAMA. 2016;315(8):801-10.
doi:10.1001/jama.2016.0287
241. Cruz AT, Lane RD, Balamuth F, et al. Updates on pediatric sepsis. J Am Coll Emerg
Physicians Open. 2020;1(5):981-993. doi:10.1002/emp2.12173
242. Fleischmann-Struzek C, Mellhammar L, Rose N, et al. Incidence and mortality of
hospital- and ICU-treated sepsis: results from an updated and expanded systematic review and
meta-analysis. Intensive Care Med. 2020;46(8):1552-1562. doi:10.1007/s00134-020-06151-x
243. Lu H, Wen D, Wang X, et al. Host genetic variants in sepsis risk: a field synopsis and
meta-analysis. Crit Care. 2019;23(1):26. doi:10.1186/s13054-019-2313-0
244. Jabandziev P, Smerek M, Michalek J, Fedora M, Kosinova L, Hubacek JA. Multiple
gene-to-gene interactions in children with sepsis: a combination of five gene variants predicts
outcome of life-threatening sepsis. Crit Care. 2014;18(1):R1. doi:10.1186/cc13174
245. Satoh K, Okuyama M, Furuya T, Irie Y, Nakae H. Severe Sepsis Caused by Bacteria
That Entered via the Intestinal Tract: A Case of Crohn's Disease in a Child. Cureus.
2020;12(8):e9822. doi:10.7759/cureus.9822
246. Barash Y, Klang E, Tau N, et al. Evolution of Inflammatory Bowel Disease Research
From a Bird's-Eye Perspective: A Text-Mining Analysis of Publication Trends and Topics.
Inflamm Bowel Dis. 2021;27(3):434-439. doi:10.1093/ibd/izaa091
247. Fiocchi C. Inflammatory Bowel Disease: Complexity and Variability Need
Integration. Front Med (Lausanne). 2018;5:75. doi:10.3389/fmed.2018.00075
248. Dhyani M, Joshi N, Bemelman WA, et al. Challenges in IBD Research: Novel
Technologies. Inflamm Bowel Dis. 02019;25(Suppl 2):S24-S30. doi:10.1093/ibd/izz077
249. Kumar M, Garand M, Al Khodor S. Integrating omics for a better understanding of
Inflammatory Bowel Disease: a step towards personalized medicine. J Transl Med.
2019;17(1):419. doi:10.1186/s12967-019-02174-1
250. de Souza HSP. Etiopathogenesis of inflammatory bowel disease: today and tomorrow.
Curr Opin Gastroenterol. 2017;33(4):222-229. doi:10.1097/MOG.0000000000000364
251. Flamant M, Roblin X. Inflammatory bowel disease: towards a personalized medicine.
Therap Adv Gastroenterol. 2018;11:1756283X17745029. doi:10.1177/1756283X17745029
252. Denson LA, Curran M, McGovern DPB, et al. Challenges in IBD Research: Precision
Medicine. Inflamm Bowel Dis. 2019;25(Suppl 2):S31-S39. doi:10.1093/ibd/izz078
79
253. D'Amico F, Rahier JF, Leone S, Peyrin-Biroulet L, Danese S. Views of patients with
inflammatory bowel disease on the COVID-19 pandemic: a global survey. Lancet
Gastroenterol Hepatol. 2020;5(7):631-632. doi:10.1016/S2468-1253(20)30151-5
254. Ben-Or O, Zelnik N, Shaoul R, Pacht A, Lerner A. The neurologic profile of children
and adolescents with inflammatory bowel disease. J Child Neurol. 2015;30(5):551-7.
doi:10.1177/0883073814521296
255. Szigethy EM, Youk AO, Benhayon D, et al. Depression subtypes in pediatric
inflammatory bowel disease. J Pediatr Gastroenterol Nutr. 2014;58(5):574-81.
doi:10.1097/MPG.0000000000000262
256. Morís G. Inflammatory bowel disease: an increased risk factor for neurologic
complications. World J Gastroenterol. 2014;20(5):1228-37. doi:10.3748/wjg.v20.i5.1228
257. García-Alanís M, Quiroz-Casian L, Castañeda-González H, et al. Prevalence of mental
disorder and impact on quality of life in inflammatory bowel disease. Gastroenterol Hepatol.
2021;44(3):206-213. doi:10.1016/j.gastrohep.2020.06.025
258. Zhang B, Wang HE, Bai YM, et al. Inflammatory bowel disease is associated with
higher dementia risk: a nationwide longitudinal study. Gut. 2021;70(1):85-91.
doi:10.1136/gutjnl-2020-320789
259. Bhamre R, Sawrav S, Adarkar S, Sakaria R, J Bhatia S. Psychiatric comorbidities in
patients with inflammatory bowel disease. Indian J Gastroenterol. 2018;37(4):307-312.
doi:10.1007/s12664-018-0870-9
260. Gassler N. Paneth cells in intestinal physiology and pathophysiology. World J
Gastrointest Pathophysiol. 2017;8(4):150-160. doi:10.4291/wjgp.v8.i4.150
261. Wehkamp J, Stange EF. An Update Review on the Paneth Cell as Key to Ileal Crohn's
Disease. Front Immunol. 2020;11:646. doi:10.3389/fimmu.2020.00646
262. Valeri M, Raffatellu M. Cytokines IL-17 and IL-22 in the host response to infection.
Pathog Dis. 2016;74(9)doi:10.1093/femspd/ftw111
80
List of Annexes
(Selected publications arranged in order of appearance in the text)
Annex 1
Jabandziev P, Hlavackova E, Bily V, Karaskova E, Kunovsky L, Ravcukova B,
Grombirikova H, Kozumplikova R, Buckova H, Slaba K, Pinkasova T, Jouza M, Pecl J,
Jezova, M, Curtisova V, Freiberger T. Trichohepatoenteric syndrome in a patient with TTC37
mutations - case report. Gastroent Hepatol. 2020; 74 (6), 481–487.
Annex 2
Jabandziev P, Pinkasova T, Kunovsky L, Papez J, Jouza M, Karlinova B, Novackova M,
Urik M, Aulicka S, Slaby O, Bohosova, J, Bajerova K, Bajer M, Goel A. Regional Incidence
of Inflammatory Bowel Disease in a Czech Pediatric Population: 16 Years of Experience
(2002–2017). J Pediatr Gastroenterol Nutr. 2020; 70 (5), 586–592.
Annex 3
Jabandziev P, Bohosova J, Pinkasova, T, Kunovsky L, Slaby O, Goel A. The Emerging Role
of Noncoding RNAs in Pediatric Inflammatory Bowel Disease. Inflamm Bowel Dis. 2020; 26
(7), 985–993.
Annex 4
Jabandziev P, Kakisaka T, Bohosova J, Pinkasova T, Kunovsky L, Slaby O, Goel A.
MicroRNAs in Colon Tissue of Pediatric Ulcerative Pancolitis Patients Allow Detection and
Prognostic Stratification. J Clin Med. 2021; 10 (6), 1325.
Annex 5
Slaba K, Noskova H, Vesela P, Tuckova J, Jicinska H, Honzik T, Hansikova H, Kleiblova P,
Stourac P, Jabandziev P, Slaby O, Prochazkova D. Novel Splicing Variant in the. Front
Genet. 2020; 11, 561054.
81
Annex 6
Formankova R, Kanderova V, Rackova M, Svaton M, Brdicka T, Riha P, Keslova P,
Mejstrikova E, Zaliova M, Freiberger T, Grombirikova H, Zemanova Z, Vlkova M, Fencl F,
Copova I, Bronsky J, Jabandziev P, Sedlacek P, Soukalova J, Zapletal O, Stary J, Trka J,
Kalina T, Skvarova Kramarzova K, Hlavackova E, Litzman J, Fronkova E. Novel SAMD9
Mutation in a Patient with Immunodeficiency, Neutropenia, Impaired Anti-CMV Response,
and Severe Gastrointestinal Involvement. Front Immunol. 2019; 10:2194.
Annex 7
Pecl J, Karaskova E, Kunovsky L, Jimramovsky F, Schneiderova H, Pinkasova, T, Veverkova
M, Jouza M, Hlouskova E, Bajerova K, Latalova V, Veghova-Velganova M, Geryk M,
Sulakova A, Toukalkova L, Jaksic D, Zimen M, Jezova M, Urik M, Wiesnerova M,
Jabandziev P., Eosinophilic esophagitis - 10 years of experience in five Czech pediatric
endoscopy centers. Gastroent Hepatol. 2020; 74 (6), 469–480.
Annex 8
Jabandziev P, Jouza M, Pecl J, Urik M, Papez J, Pinkasova T, Slaba K, Trna J, Kyclova J,
Vaculova J, Kunovsky L. Herpetic esophagitis in a 7-year-old immunocompetent patient.
Gastroent Hepatol. 2020; 74 (3), 233-237.
Annex 9
Poredska K, Kunovsky L, Marek F, Kala Z, Prochazka V, Dolina J, Zboril V, Kovalcikova P,
Pavlik T, Jabandziev P, Pavlovsky Z, Vlazny J, Mitas L. The Influence of Microscopic
Inflammation at Resection Margins on Early Postoperative Endoscopic Recurrence After
Ileocaecal Resection for Crohn’s Disease. J Crohns Colitis. 2020; 14 (3), 361–368.
Annex 10
Jabandziev P, Smerek M, Michalek J, Fedora M, Kosinova L, Hubacek JA. Multiple geneto-gene
interactions in children with sepsis: a combination of five gene variants predicts
outcome of life-threatening sepsis. Crit Care. 2014; 18 (1), R1.
82
Annex 1
83
84
85
86
87
88
89
Annex 2
90
91
92
93
94
95
96
Annex 3
97
98
99
100
101
102
103
104
105
Annex 4
106
107
108
109
110
111
112
113
114
115
116
Annex 5
117
118
119
120
121
122
123
Annex 6
124
125
126
127
128
129
130
131
Annex 7
132
133
134
135
136
137
138
139
140
141
142
143
Annex 8
144
145
146
147
148
Annex 9
149
150
151
152
153
154
155
156
Annex 10
157
158
159
160
161
162
163
164