The efficacy of antigen-specific immunoadsorption and rebound of anti-A/B antibodies in ABO-incompatible kidney transplantation.

BACKGROUND: As antigen-specific immunoadsorption (IA) using the Glycosorb®-ABO columns is becoming increasingly popular in ABO-incompatible (ABOi) transplantation, in this study, we retrospectively investigated the efficacy of Glycosorb®-ABO IA in vivo and ex vivo. We also assessed the risk of anti-A/B antibody (ABab) rebound before and after ABOi kidney transplantation.
METHODS: A protocol for ABOi living donor kidney transplantation was used, combining four preoperative and three preemptive postoperative Glycosorb®-ABO IAs with rituximab and maintenance immunosuppression. ABabs were determined by a haemagglutination titration technique.
RESULTS: ABOi kidney transplantation was attempted 45 times and 43 transplantations were performed. Overall patient survival was 93% and graft survival was 91%. Mean follow-up was 4.5 years. Glycosorb®-ABO IA significantly reduced the ABabs in the majority of patients (P < 0.0001). However, in three patients (6.8%), the antibody elimination was incomplete. Inadequate adsorption of core-chain-dependent ABabs may explain this finding, but further studies are needed. In five patients, the preconditioning was interrupted before transplantation, resulting in ABab rebound. Yet, when preconditioning was restarted, the antibodies could be removed as planned. After ABOi transplantation, rebound of ABabs was seen in two patients (5%).
CONCLUSIONS: Glycosorb®-ABO IA in combination with rituximab effectively depletes ABabs in most patients, but owing to core-chain-dependent ABabs, Glycosorb®-ABO IA may be less effective than nonspecific techniques for antibody removal in some patients. Rebound before transplantation subsequent to interrupted preconditioning does not hamper a successful ABOi transplantation. Postoperatively, when this protocol for ABOi transplantation is followed, the risk of ABab rebound is small.