Trong cấy ghép, các phân tử DR là quan trọng nhất của kháng nguyên lớp II. 3 G. HLA lớp III kháng nguyên có liên quan đến chức năng miễn dịch, đặc biệt là với hệ thống bổ sung huyết thanh. Vai trò của lớp III kháng nguyên trong việc cấy ghép chưa được hiểu rõ. | Page 32 CIgh 1 u J J B1A1 Bl Al BlB3 A ConatwMft M Figure Depicts the organization of the HLA MHC complex. Reprinted with permission from Whedon Bone Marrow Transplantation 1997. Chiomownw Ĩ F. HLA class II antigens include HLA DRB1 DRB3 DRB4 DRB5 DQA1 DQB1 DPA1 and DPB1 genes. These antigens are found mainly on B lymphocytes macrophages monocytes and dendritic cells. In transplantation the DR molecule is the most important of the class II antigens. 3 G. HLA class III antigens are involved in immune function especially with the serum complement system. The role of class III antigens in transplantation is not well understood. H. For the purpose of allogeneic transplantation the HLA genes considered to be most significant are HLA A HlA B and HLA DRB1. III. Inheritance of HLA Type A. The term phenotype refers to the HLAs observed in any individual. The phenotype is composed of two sets of antigens one inherited from each parent. B. a haplotype is the set of antigens inherited from one parent. These genes antigens are tightly linked and inherited in blocks. Each individual s phenotype is composed of two haplotypes. Page 34 will remain inactive when placed together in culture. Conversely lymphocytes from two HLA-mismatched individuals will stimulate each other when placed in culture. Traditionally this test has been used to determine HLA class II compatibility but is now becoming less widely used. D. DNA typing directly determines the HLA alleles of an individual. Typing is generally accomplished by the polymerase chain reaction technique. Restriction fragment length polymorphism may be used adjunctively to provide higher-resolution testing. E. Advantages of HLA typing 1. Provides a higher level of accuracy than other methods 2. Does not require live cells 3. Uses manufactured reagents increased availability F. Compatibility between donor and recipient is essential to minimize the potential of graft-versus-host disease GVHD graft rejection and graft failure. Risk .
