In-depth study of the human histocompatibility polymorphisms will include genetic inheritance, alleles, typing methodologies, and matching requirements for solid organ and tissue transplantation. The human leukocyte antigen (HLA or MHC) system and its role in transplant rejection will be the major focus, however minor histocompatibility systems will also be examined. Specific and detailed correlation of didactic information will be integrated with case studies to explore current concepts of immunologically-based molecular methods of antigen detection and their impact on clinical practice.