Safety and efficacy of rituximab-free ABO incompatible kidney transplantation: a German multicenter cohort study.

Abstract

Background: ABO-incompatible living kidney transplantation (ABOi-LKT) has become an established procedure with long-term patient and graft survival comparable to ABO-compatible transplantation. However, intensified immunosuppression increases the risk of severe infectious complications, particularly in the early post-transplant period. This study investigated whether ABOi-LKT in patients with low baseline anti-ABO isoagglutinin titers can be performed safely without rituximab and thereby reduce infectious complications.

Methods: In this multicenter retrospective cohort study, recipients of ABOi-LKT with low pretransplant anti-ABO titers (≤1:16) were compared according to rituximab use. Clinical outcomes, graft function, rejection episodes, surgical complications, and infectious events were analyzed.

Results: Eleven German transplant centers identified 46 patients who underwent ABOi-LKT without rituximab between 2016 and 2024 and 85 low-titer recipients who received rituximab (single dose 375 mg/m²). Baseline characteristics and median pretransplant anti-ABO titers (1:2) were comparable between groups. Patients underwent a median of two extracorporeal antibody eliminations and received comparable immunosuppression. Graft function at discharge and after 3 and 12 months, as well as proteinuria, did not differ between cohorts. One graft loss due to acute antibody-mediated rejection occurred in the rituximab-free group, whereas two graft losses (one rejection, one BK polyomavirus nephropathy) and one patient death occurred in the rituximab group. Rates of surgical complications (34.8% vs. 36.5%), blood transfusions (21.7% vs. 17.6%), and rejection episodes (15% vs. 20%; p=0.499) were similar. In contrast, infectious complications were significantly more frequent among rituximab-treated patients, with a 2.4-fold increased infection risk (p=0.018). Infection-related hospitalizations occurred significantly more often in the rituximab group (64.6% vs. 31.3%; p=0.003).

Conclusions: ABOi-LKT without rituximab appears safe in recipients with low pretransplant anti-ABO titers. Short-term graft function, graft survival, patient survival, and immunological outcomes were comparable to rituximab-based desensitization. Importantly, omission of rituximab was associated with significantly fewer infectious complications and infection-related hospitalizations, supporting a tailored, lower-intensity immunosuppressive approach in selected low-risk patients.