ABO-incompatible living donor kidney transplantation in Portugal

Abstract

Introduction: ABO incompatibility was considered a barrier to kidney transplant. However, the shortage of available organs for transplantation and the excellent long-term results further establish ABO-incompatible (ABOi) as a safe and effective therapeutic strategy. The aim of the present study was to evaluate the outcomes of ABOi transplantation in terms of graft survival and function, rejection episodes and infections complications. Methods: The authors present a single-center retrospective observational study in a unit with approximately 370 living donor kidney transplants registered. This study includes the analysis of 12 patients who underwent ABOi living donor kidney transplantation between November 2014 and July 2019. Desensitization protocol consisted of intravenous Rituximab 375mg/m 2 single dose administration 2 weeks pretransplant. Tacrolimus and Mycophenolate Mofetil were started before transplantation one week and 48 hours respectively. Plasmapheresis was performed to remove anti-A or B antibodies until their titers were <1:8 during the first post-operative week and <1:16 at the second. All kidney recipients of both ABOi grafts received Basiliximab (20mg on days 0 and 4) as antibody induction therapy. Maintenance immunosuppression consisted of Tacrolimus, Mycophenolate Mofetil and corticosteroid. Results: A total of 12 patients were included in the study, 75% male; 43 years (IQR 31-50). The most common blood group mismatch was A to O (n=4; 33%). In the first year, 2 of patients (25%) developed acute rejection. The follow-up time was 17 months (IQR 7-36). Five patients (42%) developed infectious complications. None patients developed cytomegalovirus or BK polyomavirus infections. At the end graft and patient survival were 100%. Conclusion: ABOi kidney transplantation has become a routine procedure. With this approach, about 30% of living donors who were refused in the past can now donate their kidneys and thereby significantly expand the living donor pool. The immunosuppressive protocol of this unit can be considered safe.