ABO-incompatible kidney transplantation: impact of apheresis on graft and patient survival in recipients with low isoagglutinin titer

Abstract

ABO-incompatible (ABOi) kidney transplantation carries a high risk of acute antibody-mediated rejection due to the presence of isoagglutinins. To mitigate this risk, current protocols recommend performing apheresis before transplantation. Our objective was to evaluate outcomes in ABOi recipients with low isoagglutinin titers, comparing those who did and did not undergo pre-transplant apheresis. We conducted a multicenter study including recipients of ABOi kidney transplants between 2012 and 2022. A total of 78 patients with baseline isoagglutinin titers ≤1:8 were included; 41 received pre-transplant apheresis, 37 did not. Patients who did not undergo apheresis had more rejection episodes (p=0.01), and a trend toward higher rates of delayed graft function and antibody mediated rejection, which adversely impacted patient and graft survival. At 3 years, event-free survival (death or graft loss) was 90% in the apheresis versus 79% in the no-apheresis group (p=0.02). In multivariable analysis, factors associated with improved event-free survival included pre-transplant apheresis (HR=0.31, p=0.049) while ABMR within the first month was associated with poorer outcome (HR=5.18, p=0.0007). No differences emerged regarding the occurrence of overall infections. These findings suggest that apheresis should be systematically performed prior to ABOi transplantation, regardless of baseline isoagglutinin titer.