Are transplantation antigens stable constituents on human renal allografts?

The majority of cadaveric kidney transplants suffer at most one rejection episode, thereafter the postoperative course is usually uneventful. The remaining transplants have repeated rejections terminating often in prolonged irreversible rejection and transplant removal. We have been curious about this difference and analysed whether the two types of grafts display equally the major histocompatibility (MHC) antigens on their surface. Using monospecific rabbit antisera to HLA-ABC and -DR and/or alloantisera directed to allelic determinants of HLA-A and -B, we were unable to demonstrate the MHC antigens in most of the 'well-functioning' kidneys whereas these antigens were almost regularly present on the vascular endothelial cells of transplants with repeated and irreversible rejections.