Influence of human leukocyte antigen mismatching on rejection development and allograft survival in liver transplantation: is the relevance of HLA-A locus matching being underestimated?

The influence of HLA matching on liver transplant is still controversial, as studies have failed to demonstrate an adverse effect of HLA mismatching on transplant outcome. We examined the effect of HLA mismatching on transplant outcome in a series of 342 consecutive liver transplants (224 finally analyzed). HLA typing was performed by serological and molecular methods. HLA-A matching was associated with an increased chronic rejection incidence (P=0.04). Indeed, HLA-A match also demonstrated a significant impact on allograft survival (P=0.03), confirming previous observation concerning to rejection, as complete HLA-A mismatching favored a better liver transplant outcome. Analysis of HLA-A+B+DR matching also demonstrated a significant impact on graft survival (P<0.05). Multivariate Cox regression analysis confirmed the effect of HLA-A and DPB1 matching as independent risk factors for graft loss. Another independent factor was a positive pre-transplant crossmatch. In conclusion, liver transplant outcome has not been found to be improved by HLA matching, however a poorer HLA compatibility favored a better graft survival and decreased rejection incidence, with a special relevance for HLA-A matching.