Repeat HLA-B and -DR loci mismatching at second liver transplantation improves patient survival

The role of HLA matching in liver transplantation remains uncertain, and the effect of HLA mismatches on the outcome of second transplants has not been studied. In renal transplantation, if HLA mismatches are repeated in the second graft there is a greatly increased risk of immunological graft failure. In the present study, 78 patients who had received second liver transplants were studied. HLA typing was performed using standard complement-dependent microcytotoxicity for class I (A and B) antigens, and a combination of restriction fragment length polymorphism and serology for HLA-DR. Patient survival at follow-up for those with a repeat B locus mismatch was improved (79% compared with 43%, P < 0.02), and a similar effect was noted for repeat DR mismatches (67% vs. 47%, P = 0.06). In the subgroup of patients who received a second transplant for graft rejection, 90% of patients with a repeat B mismatch were alive at follow-up compared with 46% without B mismatches (P = 0.02). This improvement in patient survival was evident during the first 2 months after the second transplant. In this study, repeat HLA-B and -DR mismatching improves survival after second transplantation.