Better HLA Matching Is Associated With First and Second Allograft Outcomes Among Pediatric Kidney Transplant Recipients.

Abstract

Introduction: Kidney transplant(KT) graft survival is superior if received from ideal well-matched donors. Given the decline of living donor(LD) availability and the initiation of the Share35 kidney policy, we sought to determine the impact of Human Leukocyte Antigen(HLA) matching on allograft outcomes. Methods: A retrospective analysis of OPTN data(1988-2009) examining pediatric first and second KT allograft survival based on Share35 policy, HLA matching(0-2 vs 3+), and donor-type(LD vs Deceased Donor=DD) using Kaplan-Meier statistics and Cox regression analysis. Results:Of 13,489 first KT pediatric recipients, post-Share35 groups had poorer(0-2 antigen) matched grafts(64.88%) compared to the pre-Share35 cohort(39.69%; p<0.01), even when stratified by donor type. Additionally, there was a significant decline in LD availability post-Share35 initiation(-20.17%; p<0.01). Despite these findings, favorable graft outcomes exist for post-Share35 and LD recipients(p<0.01).Figure: No Caption available.Adjusting for all factors, better HLA-matching(HR=0.80; p<0.01), LD allografts(HR=0.65; p<0.01), and post-Share35 transplantation(HR=0.72;p<0.01) conferred better graft outcomes. In a secondary analysis, recipients with poorly matched(0-2 antigen) grafts at first transplant who underwent second kidney transplant, median wait-list time prior to second kidney transplant was longer(p<0.01), while second kidney graft survival was shorter(p=0.02). We also determined that better first HLA matching correlated with lower peak PRA level at second transplant(-0.14; p<0.01). Conclusion: Among pediatric kidney transplant recipients, improved allograft outcomes exist for better HLA-matched first and second transplants, despite Share35 policy initiation and decline of LD availability. HLA matching retains its prognostic value in graft outcomes for first and subsequent kidney transplants. This does not explain the improved early graft outcomes we see in the post-Share35 era. Finally, patients who are better matched for previous transplants are less sensitized, have shorter wait-list times, and overall longer subsequent allograft survival times.