antigenmatching

Antigen matching is the process of comparing immunogenic markers between donor and recipient to reduce the probability of an adverse immune response after tissue or organ transfer. In clinical settings, matching typically concentrates on human leukocyte antigens (HLA) and blood group antigens, though other antigen systems may be relevant for specific procedures.

In solid organ transplantation, ABO compatibility is required and HLA compatibility improves graft survival and lowers rejection risk. The degree of HLA matching is assessed by allele-level or antigen-level typing for Class I (HLA-A, -B, -C) and Class II (HLA-DR, -DQ, -DP). Mismatch counts are used in decision-making, e.g., 6/6 or 8/8 matches for certain organs; higher-resolution typing can yield 10/10 matching in some programs. Donor-specific antibodies and crossmatching influence donor selection via PRA scores and crossmatch results (complement-dependent cytotoxicity or flow cytometry crossmatches).

Typing methods have evolved from serology to DNA-based techniques, including PCR-based methods and next-generation sequencing, enabling higher resolution and better discrimination of closely related HLA alleles. Matching decisions balance immunologic risk with donor availability, and unavailability of a perfect match may still yield successful outcomes with immunosuppression.

In transfusion medicine, antigen matching focuses on ABO and Rh(D) status for red blood cells, with additional consideration of clinically significant antigens such as Kell, Duffy, Kidd, and MNSs to reduce alloimmunization, particularly in patients requiring chronic transfusions. In hematopoietic stem cell transplantation, HLA matching is decisive, with cord blood and matched unrelated donors expanding options for patients without a familial match.

Beyond HLA, minor histocompatibility antigens and non-HLA antigens can influence rejection and graft-versus-host disease. Sensitization from prior transfusions or pregnancies increases PRA and can complicate matching. Advances in high-resolution typing, better understanding of antigen landscapes, and personalized immunosuppression continue to refine matching strategies and transplant outcomes.