Successful ABO-incompatible kidney transplantations without splenectomy using antigen-specific immunoadsorption and rituximab

Background. Historically, ABO-incompatible kidney transplantations have only been undertaken after splenectomy and unspecific plasmapheresis and with quadruple drug immunosuppression plus B-cell specific drugs. We have evaluated a protocol for ABO-incompatible kidney transplantation without splenectomy using antigen-specific immunoadsorption, rituximab, and a conventional triple-drug immunosuppressive regimen. Methods. The protocol called for a 10-day pretransplant conditioning period starting with one dosage of rituximab and followed by full dose tacrolimus, mycophenolate mofetil, and prednisolone. Antigen-specific immunoadsorption was performed on pretransplant days - 6, - 5, - 4, and - 1. After the last session, 0.5 g/kg of intravenous immunoglobulin was administered. Postoperatively, three more apheresis sessions were given every third day. Furthermore, if there was a significant increase in the antibody titers, extra sessions were considered. Results. Four patients have received transplants with this protocol. The donor-recipient blood groups were A2/O, B/O, B/A, and A1/O. The ABO-antibodies were readily removed by the antigen-specific immunoadsorption and were kept at a low level posttransplantation by further adsorptions. There were no side effects, and all patients have normal renal-transplant function. Conclusions. We conclude that after one infusion each of rituximab and intravenous immunoglobulin and antigen-specific immunoadsorption, blood-group-incompatible renal transplantations can be performed with standard immunosuppression and without splenectomy.