Immunology of transplantation Types of transplantation •Autotransplantation –within one organism •Allotransplantation- between one species •Xenotransplantation- between two different species • 01 CH13F29 Success rate of transplantation in humans D:\SCContent\9780323043311\graphics\fullsize\M43311-008-f002.jpg Downloaded from: StudentConsult (on 4 August 2013 10:57 AM) © 2005 Elsevier Polymorphism of HLA antigens Co-dominant expression of HLA genes Requirements before solid organ transplantation •ABO blood groups compatibility •Negativity of cross match test •HLA „similarity“ (does not play a significant role in heart and liver transplantation) Effect of HLA-identity on kidney graft survival • Cross match test •Used for detection of recipient´s antibodies against donor´s antigens (mainly HLA antigens) •Donor´s leukocytes + patient´s plasma •Positivite – antibodies bind to leukocytes – can be detected e.g. by flow cytometry •Positivity contraindicates transplantation 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 •Many other organs •Extremities, face… • • Hematopoietic 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…). •