Immunology of transplantation



Types of transplantation
•Autotransplantation –within one organism
•Allotransplantation- between one species
•Xenotransplantation- between two different species

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CH13F29
Success rate of transplantation in humans


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© 2005 Elsevier
Polymorphism of HLA antigens

Co-dominant expression of HLA genes



Effect of HLA-identity on kidney graft survival



Types of graft rejection
•Hyperacute - minutes to hours after transplantation. Caused by pre-formed recipient antibodies
against HLA antigens of the donor. Irreversible.
•Acute -several days to months after transplantation. Mainly T-cell mediated. Usually reversible by
aggressive immunosuppression.
•Chronic - years after transplantation. Continuous decrease in graft function. Irreversible.
Mechanism  unknown.

The most frequent types of organ transplantation
•Heart
•Kidney
•Liver
•Lungs
•Pancreas
•Cornea
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Heamatopoietic stem cells  transplantation
•Indications: malignancies, bone marrow failure, primary immunodeficiencies.
•“Whole“ bone marrow or separated CD34+ cells can be used.
•The most significant complication: graft-versus host reaction (GVHR).
•Optimal HLA-matched donor is required.

Graft-versus host reaction (GVHR)
•Immunological reaction of transplanted T-cells against recipients (HLA) antigens.
•Skin, liver, intestine predominantly affected.
•Milder forms  can be treated by immunosuppression, severe forms may be fatal.
•Can be induced by transfusion of non-irradiated blood to immunodeficient patients (primary
immunodeficiencies, leukemia…).
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Systemic Immunosuppression
•High-dose steroids
•Purine antagonists: Azathioprin
•Alkylating agents: Cyclophosphamide
•Anti-pholates: Methotrexate
•Calcineurin antagonists: Cyclosporine A, Rapamycin, Tacrolymus
•Block of purins synthesis: Mycophenolate
•Monoclonal antibodies: anti-CD3, anti-CD20, anti-CD54