Irene Feurer

Introduction Data on long‐term outcomes following A2/A2B to B kidney transplants since the 2014 kidney allocation system (KAS) changes are few. The primary aim of this study is to report our 7‐year experience with A2/A2B to B kidney transplants and to compare post‐transplant outcomes of A2/A2B to a concurrent group of B to B kidney transplants. Additionally, the study evaluates the impact of pre‐transplant anti‐A1 titers on survival outcomes in A2/A2B transplants. Methods This retrospective, single‐center analysis included all adults who received A2/A2B to B deceased donor kidney transplants from December 2014 to June 2021 compared to B to B recipients. The effects of pre‐transplant IgM/IgG titers, stratified as ≤1:8 and ≥1:16, on death‐censored, rejection‐free, and overall graft survival were tested. Results Fifty‐three A2/A2B and 114 B to B adults were included with a median follow‐up time of 32 months. Overall graft survival, patient survival, and rejection‐free graft survival did not differ between the two groups. There were no differences between the groups’ overall kidney function values ( p > .80) or their temporal trajectories (time by group interaction p > .11). Unadjusted death‐censored graft survival was lower in A2/A2B to B compared to B recipients ( p = .03), but the effect was not significant ( p = .195) after adjusting for any readmissions ( p = .96), rejection episodes ( p < .001) or BK infection ( p = .76). We did not detect an effect of pre‐transplant titer group on death‐censored ( p = .59), rejection‐free ( p = .61), or overall graft survival ( p = .26) Conclusions A2/A2B to B kidney transplants have comparable overall patient and graft survival, rejection‐free graft survival, and longitudinal renal function compared to B to B transplants at our center. Allograft survival outcomes were not significantly different between patients with low and high pre‐transplant anti‐A1 IgM/IgG titers.