ABO-incompatible kidney transplantation with antigen-specific immunoadsorption and rituximab - insights and uncertainties.

Several protocols have been developed to effectively overcome the blood group barrier in renal transplantation. In the evolution of these protocols, one of the latest steps was the combination of anti-CD20 treatment with antigen-specific immunoadsorptions. Over the last years we have learned that these relatively new protocols carry very promising short-term and intermediate-term results which compare favorably to the outcome of ABO-compatible living donor transplantations. Latest reports suggest that combining immunoadsorptions with rituximab does not result in an increased risk of infectious complications or tumors in the first years after transplantation compared to ABO-compatible living donor transplantations. We recently demonstrated that a majority of patients with isoagglutinin titers >1:128 can be safely transplanted using rituximab and immunoadsorptions without an added risk of early antibody-mediated rejections. We have also shown that a cost saving 'on-demand strategy' of postoperative immunoadsorptions based on careful titer monitoring can be used as an alternative to preemptively scheduled immunoadsorptions. Although rituximab and antigen-specific immunoadsorptions are significantly less invasive than splenectomy and plasma-pheresis, long-term follow-up of patients treated with a combination of anti-CD20 antibody and antigen-specific immunoadsorption will be needed to benchmark this therapeutic option in relation to more established protocols.