A2/A2B Deceased Donor Kidney Transplantation Using A2 Titers Improves Access to Kidney Transplantation: A Single-Center Study

Rationale & Objective: The option for A2/A2B deceased donor kidney transplantation was integrated into the kidney allocation system in 2014 to improve access for B blood group waitlist candidates. Despite excellent reported outcomes, center uptake has remained low across the United States. Here, we examined the effect of implementing an A2/A2B protocol using a cutoff titer of <= 1:8 for IgG and <= 1:16 for IgM on blood group B kidney transplant recipients at a single center. Study Design: Retrospective observational study. Setting & Participants: Blood group B recipients of deceased donor kidney transplants at a single center from January 1, 2019, to December 2022. Exposure: Recipients of deceased donor kidney transplants were analyzed based on donor blood type with comparisons of A2/A2B versus blood group compatible. Outcomes: One -year patient survival, deathcensored allograft function, primary nonfunction, delayed graft function, allograft function as measured using serum creatinine levels and estimated glomerular filtration rate at 1 year, biopsy-pro ven rejection, and need for plasmapheresis. Analytical Approach: Comparison between the A2/A2B and compatible groups were performed using the Fisher test or the chi( 2) test for categorical variables and the nonparametric Wilcoxon ranksum test for continuous variables. Results: A total of 104 blood type B patients received a deceased donor kidney transplant at our center during the study period, 49 (47.1%) of whom received an A2/A2B transplant. Waiting time was lower in A2/A2B recipients compared with blood group compatible recipients (57.9 months vs 74.7 months, P = 0.01). A2/A2B recipients were more likely to receive a donor after cardiac death (24.5% vs 1.8%, P < 0.05) and experience delayed graft function (65.3% vs 41.8%). There were no observed differences in the average serum creatinine level or estimated glomerular filtration rate at 1 month, 3 months, and 1 year post kidney transplantation, acute rejection, or primary nonfunction. Limitations: Single -center study. Small cohort size limiting outcome analysis. Conclusions: Implementation of an A2/A2B protocol increased transplant volumes of blood group B waitlisted patients by 83.6% and decreased the waiting time for transplantation by 22.5% with similar transplant outcomes.