Isoagglutinin titre adsorption: Breaking the barrier in major AB0-incompatible organ transplantation

Blood group AB0-incompatible live donor (LD) renal transplantation may provide a significant source of organs. AB0-incompatible LD renal transplantation can be accomplished using specific anti-A/B antibody (Ab) immunoadsorption (IA) and anti-CD20 monoclonal Ab (Rituximab®) treatment. One dose of anti-CD20 mAb (rituximab, 375 mg/m2) is given for weeks pre-operatively. Recipients are pre-treated with 3–5 sessions of immunoadsorption, using A or B carbohydrate antigen specific columns, until their anti-A1/B RBC panel indirect antiglobulin test (IAT) titres are <8. Polyclonal immunoglobulins are applied four days before transplantation. Recipients receive preoperative mycophenolic acid, steroids/tacrolimus therapy. No splenectomy was performed. Postoperative IA is applied if RBC panel indirect antiglobulin test (IAT) titres are >8. Postoperative renal biopsies may yield positive C4d staining in peritubular capillaries as sign of humoral immune activation but the clinical course is favourable if IAT titres can be kept below 8 within the first weeks after transplantation. This protocol has excellent short-term and long-term graft survival as well as function although recipient anti-A/B titres after transplantation return to pre-surgical levels within months after transplantation.