Minor histocompatibility antigens as risk factor for poor prognosis in kidney transplantation

Progress in transplantation has relied on similar human leukocyte antigen (HLA) matching between the donor and the patient, while the role of other immunologic factors like non-HLA markers including minor histocompatibility antigens (miHA) are currently in the forefront. miHA are polymorphic proteins that vary even in monozygotic twins. The best known is the H-Y antigen, but there are also other autosomal miHA and MICA (MHC class I chain-related gene A). miHA have been well studied in transplantation of hematopoietic precursors, but not in solid organ transplantation. The most important studies in this field relate to incompatibility of H-Y antigen as a risk factor in kidney transplantation, although the findings are still inconclusive. This review presents the role of minor histocompatibility antigens in solid organ transplantation, especially of the kidney.