2000;69(3):319C26

2000;69(3):319C26. antibodies was known in kidney transplantation over 40 years back initial, and understanding of their significance pass on towards the transplantation of various other solid organs in following years (1). This review will mainly concentrate on the presssing problems connected with sensitization in pediatric center transplantation, with some sources towards the various other solid body organ transplants. Although an in depth description from the advancement of the antibodies and the techniques used for testing is certainly beyond the range of this section, a construction will be provided which all of those other dialogue will occur. For readers thinking about further information on this subject, there are a few exceptional lately released testimonials (2,3). ANTI-HLA ANTIBODIES Anti-HLA antibodies are antibodies directed against antigens on Class Eugenin I and Class II major histocompatibility complexes. Class I molecules are found on all nucleated cells in the body, and Class II expression is observed predominantly on antigen-presenting cells and activated endothelial cells (3-5). Anti-HLA antibodies can form prior to transplantation in response to exposure to Eugenin foreign antigens. There are a number of situations that place a child at risk of developing anti-HLA antibodies prior to transplantation, with some of these being common to all solid organ transplants and others being organ-specific. Common risk factors for the development of anti-HLA antibodies include the transfusion of blood products (especially those that contain Cd19 leukocytes and Eugenin platelets), previous organ transplantation, and a history of pregnancy (6,7). Risk factors that are unique to the cardiac population include previous cardiac surgery, especially surgery that requires exposure to homograft materials for surgical reconstruction, and the implantation of ventricular assist devices for mechanical support (6,8-12). ANTIBODY TESTING The presence and degree of anti-HLA antibody development is an important part of the pretransplant evaluation for a potential transplant candidate. HLA antibody screening is performed to determine the presence or absence of HLA antibodies and, with more recent testing, the HLA target and titers of these antibodies. Anti-HLA antibodies can be detected using HLA antigens that are either cell-based or part of a solid-phase assay (non-cell based) (3,13). Cell-based strategies Class I HLA molecules can be found on the intact cell membrane of either T- or B-lymphocytes, with Class II molecules being limited to B-lymphocytes. These cells provide the target antigens for the detection of anti-HLA antibodies in cell-based assays. Cell-based assays may rely on the binding of complement, as in the Complement-Dependent Cytotoxicity (CDC) assay, to determine the presence of HLA antibodies, or they can be conducted independent of the binding of complement, such as in flow cytometry (3). The CDC assay determines the percentage of lymphocytes that undergo cell death when a patient’s serum is added in the presence of complement. Flow cytometry avoids the need for complement, as fluorescently tagged anti-human globulin is used to detect the presence of anti-HLA antibodies bound to the lymphocyte cell membrane. These tests can be used to determine the percentage of cell samples from a given population to which a recipient would react (panel reactive antibody) and in turn represent the HLA antigens that would be present in a donor pool from the same population (3). Both CDC assays and flow cytometry can also Eugenin be used to determine whether a recipient has antibodies to a particular donor (crossmatch) and therefore help to predict the existence of a potential risk of antibody-mediated rejection if that organ is transplanted (3). Cell-based assays range in sensitivity, with CDC methods being the least sensitive and flow cytometry being the most sensitive (2,3,14). These assays can result in both false.