Impact of Human Leukocyte Antigen-DR Mismatch Status on Kidney Graft Survival in a Predominantly African-American Population Under the Newer Immunosuppressive Era

Abstract Background Human leukocyte antigen (HLA)-DR has been shown to be immunogenic and associated with poor long-term graft function. However, under potent induction immunosuppression with antithymocyte globulin, the impact of the HLA-DR remains unclear. Method We reviewed 672 renal transplant recipients who received their transplants between 1998 and 2007. All patients received antithymocyte globulin as induction therapy followed by tacrolimus + prednisone + mycophenolate mofetil for maintenance immunosuppression. We divided the patients into three groups according to HLA-DR mismatch status (zero, one, or two mismatches). Results The three groups were different in total number of mismatches, deceased donor transplant, and delayed graft function, respectively. By Kaplan-Meier survival analysis, actuarial graft survival was significantly lower in the HLA-DR two mismatches group (72%) compared to HLA-DR zero mismatches group (78.5%) or HLA-DR one mismatch group (78.5%; P = .05, by log-rank test). Using Cox regression analysis, the risk of graft failure with two HLA-DR mismatches as compared with zero HLA-DR mismatches was 1.6 (95% confidence interval = 1.0–2.44, P = .049). When adjusted for age, wait time, race, type of transplant, retransplant status, T-cell flow crossmatch, delayed graft function, acute rejection, HLA-A and HLA-B, the effect of HLA-DR on survival was not significant ( P = .55). Conclusion The independent effect of HLA-DR mismatches on adverse graft survival is diminished under potent antibody induction and maintenance immunosuppression in our predominantly African-American population.