Impact of non-inherited maternal antigen and minor histocompatibility antigen on renal allograft outcome

Abstract

BackgroundGraft rejection that occur on the face of a fully HLA matched transplant setting have been shown to be caused by disparities in other antigenic systems viz. Minor Histocompatibility Antigens (MiHAs), endothelial antigens etc. The Non-inherited Maternal Antigens (NIMAs) similarly have been shown to offer advantage in clinical transplantation. AimTo investigate the role of NIMAs vis-a-vis MiHAs in renal transplantation. MethodsWe recruited 20 sibling donor–recipient pairs for the study. HLA typing was done by serology and the NIMA antigens deduced. MiHA was determined by sequence specific priming (SSP) and the degree of MiHA mismatch was analyzed in the NIMA and Non-inherited Paternal Antigens (NIPA) mismatched recipients and correlated with graft function/rejection. ResultsNIMA mismatch was observed in 6 cases, NIPA mismatch in 4 cases, 5 were HLA identical siblings and 5 were non-identical siblings. Acute rejection occurred in 2 of the 4 NIMA mismatched recipients whereas only a single recipient in the NIPA mismatched group experienced acute rejection. MiHA mismatches were observed in both the NIMA mismatched recipients who experienced rejection. ConclusionThe observations suggest that rejection can be caused by MiHA mismatches in a setting of acceptable major HLA mismatch viz. NIMA. The observations however need to be confirmed in a larger cohort.