Human leukocyte antigen matching in heart transplantation: systematic review and meta-analysis

Allocation of donors with regard to human leukocyte antigen (HLA) is controversial in heart transplantation. This paper is a systematic review and meta-analysis of the available evidence. PubMed, Embase, and the Cochrane Library were searched systematically for studies that addressed the effects of HLA matching on outcome after heart transplantation. Fifty-seven studies met the eligibility criteria. 34 studies had graft rejection as outcome, with 26 of the studies reporting a significant reduction in graft rejection with increasing degree of HLA matching. Thirteen of 18 articles that reported on graft failure found that it decreased significantly with increasing HLA match. Two multicenter studies and nine single- center studies provided sufficient data to provide summary estimates at 12 months. Pooled comparisons showed that graft survival increased with fewer HLA-DR mismatches [0-1 vs. 2 mismatches: risk ratio (RR) = 1.09 (95% confidence interval (CI): 1.01-1.19; P = 0.04)]. Having fewer HLA-DR mismatches (0-1 vs. 2) reduced the incidence of acute rejection [(RR = 0.81 (0.66-0.99; P = 0.04)]. Despite the considerable heterogeneity between studies, the short observation time, and older data, HLA matching improves graft survival in heart transplantation. Prospective HLA-DR matching is clinically feasible and should be considered as a major selection criterion.