The impact of donor/recipient age difference and HLA mismatch on graft outcome in pediatric kidney transplantation

Background Understanding the relationship between the factors that influence long-term kidney transplant survival remains a key priority for pediatric nephrologists. We assessed the relative impact of donor/recipient age difference and HLA matching on long-term graft outcomes. MethodsResultsWe conducted a retrospective cohort study of pediatric and adolescent recipients who received a primary kidney transplant in Australia and New Zealand between January 1, 1990, and December 31, 2015. The primary outcome was graft survival analyzed by Kaplan-Meier method. During the 26-year period, 1134 primary (395 DD and 739 LD) kidney transplants were performed in recipients less than 20years of age. The median follow-up time was 10.2years. Overall, 405 patients (35.7%) lost their transplant with graft survival 93.8% at 1year, 82.5% at 5years, 65.8% at 10years, and 49.9% at 15years post-transplant. There was consistently higher graft loss of DD kidneys as compared to LD kidneys at each time point. Both increasing donor/recipient age difference (aHR 1.11 per 10years; 95% CI, 1.02-1.20; P=0.009) and increasing HLA mismatch (aHR 1.20 per mismatch; 95% CI, 1.10-1.30; P<0.001) were associated with decreased graft survival. ConclusionsDonor/recipient age difference and HLA matching are important factors influencing long-term graft outcomes in pediatric kidney transplantation. HLA mismatch remains a strong predictor of graft loss. For patients without the option of a LD, we suggest that the degree of HLA mismatch should not be discounted as part of the decision-making process of organ allocation.