First report on the OPTN national variance: Allocation of A2/A2B deceased donor kidneys to blood group B increases minority transplantation

Abstract

In 2002, the Organ Procurement and Transplantation Network (OPTN) Minority Affairs Committee (MAC) implemented a national, prospective, "variance of practice" to allow deceased donor, ABO blood group incompatible, A2 antigen, kidney transplantation into blood group B recipients; outcomes of this cohort were compared to ABO compatible recipients. The goal of the variance was to increase the number of transplants to B candidates without negatively impacting survival or compromising system equity. Only B recipients with low anti-A IgG titers (<1:8) were eligible to receive these kidneys. Across eight participating Donation Service Areas (DSA), there were 101 A2/A2B to B transplants through 12/31/11, of which the majority of the recipients (61%) were ethnic minorities. At 12, 24, and 36 months, Kaplan-Meier graft survival rates for the B recipients of A2/A2B kidneys were 95.0%, 90.6%, and 85.4%, respectively, comparable to outcomes for B recipients of B kidneys, 92.6%, 87.9%, and 82.5%, respectively (p-value = 0.48). Five DSAs increased the proportion of B transplants during 41 months postvariance, with a lesser proportional decrease in blood group A transplants. The data support the proposition that this allocation algorithm may provide a robust mechanism to increase access of blood group B minority candidates to kidney transplantation. In this first report on the OPTN/UNOS/Minority Affairs Committee-sponsored variance of practice to allow deceased donor, A2 donor antigen, ABO-incompatible kidney transplantation into blood group B recipients, the authors provide evidence that the outcomes for these cohorts are identical to blood group B-to-B controls, and that this new rule provides a robust and equitable mechanism to increase the rate of transplantation for ethnic minorities in the U.S.