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, death-censored allograft function, primary nonfunction, delayed graft function, allograft function as measured using serum creatinine levels and estimated glomerular filtration rate at 1 year, biopsy-proven rejection, and need for plasmapheresis.

ANALYTICAL APPROACH

Comparison between the A2/A2B and compatible groups were performed using the Fisher test or the χ test for categorical variables and the nonparametric Wilcoxon rank-sum 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,  = 0.01). A2/A2B recipients were more likely to receive a donor after cardiac death (24.5% vs 1.8%,  < 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.