ABO Antibody Titer Dynamics and Optimization in Incompatible Renal Transplants Using Therapeutic Plasma Exchange

Background ABO-incompatible kidney transplantation (ABOi KT) expands access to living-donor organs but requires careful control of pre-existing anti-ABO isoagglutinins to minimize antibody-mediated rejection (ABMR). The present study was designed with the following objectives: The primary objective was to assess the relationship between baseline anti-ABO IgG titers (≥ 64 vs. < 64) and the intensity of therapeutic plasma exchange (TPE) required pre- and post-transplant, as well as ABMR incidence. The secondary objective was to evaluate graft function, patient and graft survival, and the frequency and severity of TPE-related adverse events using a standardized TPE-based desensitization protocol in a resource-limited center. Methods In this prospective single‑center study, 20 dialysis‑dependent recipients of live‑related ABOi KT received tacrolimus‑based immunosuppression, TPE, intravenous immunoglobulin, rituximab, and anti‑thymocyte globulin. ABO IgG and immunoglobulin M titers were monitored serially. Patients were stratified by high (≥64) versus low (<64) baseline IgG titers. Primary outcomes were pre‑ and post‑transplant TPE requirements and ABMR incidence; secondary outcomes included graft function, patient and graft survival, and TPE‑related adverse events. Results Across the cohort, 144 TPE sessions were performed. Recipients with high baseline IgG titers required more pretransplant TPE than those with low titers (mean 5.2 ± 1.75 standard deviation vs 3.4 ± 1.3; p = 0.02), whereas post‑transplant TPE use was comparable. ABMR occurred in 45 % of patients and was more frequent in the high‑titer group, though the difference was not statistically significant. Most recipients maintained stable graft function at 24 months, patient survival was high, and TPE‑related adverse events were infrequent and mild. Conclusions Higher baseline IgG titers increase the need for pretransplant desensitization but do not drive additional post‑transplant TPE. An individualized, TPE‑centered protocol can safely and effectively enable ABOi KT in resource‑constrained settings, underscoring the value of risk‑adapted strategies and real‑time immunomonitoring to optimize transplant outcomes.