The Excellent Outcomes of ABO-Incompatible Kidney Transplantation With High Titer (>x2048) Using Anti-CD20 and Anti-CD25 Antibody Without Splenectomy: Two Case Reports

Background. Due to the shortage of deceased donors, we have expanded the indications for living-donor kidney transplantation (LKT) to include ABO-incompatible (ABO-i) individuals. However, which patients with high-titer anti-blood-group antibody can be transplanted successfully is unclear. Methods. Since 2009 we have performed 2 high-titer ABO-i spousal LKT using anti-CD20 and anti-CD25 monoclonal antibody without splenectomy. In both cases, anti-type A antibody was 2048-fold before antibody removal. The immunosuppressive regimen consisted of 2 doses of anti-CD20 antibody (200 mg/body, day -14 to day -7), mycophenolate mofetil (1000 mg), prednisolone (10 mg starting from day -14), calcineurin inhibitor (cyclosporine [7 mg/kg] or tacrolimus [0.2 mg/kg] starting from day -7), and 2 doses of anti-CD25 antibody (20 mg/body, days 0 and 4). Antibody removal by plasmapheresis was performed up to 4 times before LKT according to the antibody titer. The posttransplantation regimen consisted of mycophenolate mofetil or mizoribine as antimetabolite. A protocol biopsy was performed at 1 month and 1 year after LKT. Result. The 60- and 62-year-old men had renal graft transplantation performed in the right hemipelvis without complication. After LKT, urinary output and serum creatinine decrease were within acceptable ranges without evidence of an acute rejection episode for 12 and 7 months, respectively. Patient and graft survival rates were 100%. A protocol biopsy at 1 month after LKT showed additional treatment to be unnecessary. Serious viral infection was not seen, even in the 1 patient who temporarily experienced positive changes in cytomegalovirus antigenemia. Conclusions. We obtained good clinical results among 2 high-titer ABO-i LKT using anti-CD20 and anti-CD25 antibodies without splenectomy, in conjunction with a calcineurin inhibitor plus mycophenolate mofetil or mizoribine.