The low dose of rituximab in ABO-incompatible kidney transplantation without a splenectomy: a single-center experience.

PURPOSE: A new protocol for ABO-incompatible (ABO-i) kidney transplantation including rituximab was introduced in January 2005 in our institute. This study reviewed the results and evaluated the use of low-dose rituximab in ABO-i kidney transplantation. MATERIAL AND METHODS: Seventy-four de novo ABO-i kidney transplantations were performed at Tokyo Women's Medical University between January 2005 and August 2010. The immunosuppressive protocol was consisting of tacrolimus, mycophenolate mofetil, and methylprednisolone. All the patients received induction therapy with basiliximab. The pre-conditioning protocol included double-filtration plasmapheresis and a single dose of rituximab. A dose of 500 mg/body rituximab was initially employed and yielded excellent results (Group I, n = 24). Afterward, the dose of rituximab was reduced to 200 mg/body in January 2007 (Group II, n = 50). RESULTS: Seventy-four de novo ABO-i recipients were treated with this protocol, and all patients underwent kidney transplantation successfully. Effective elimination of the peripheral blood CD19 cells was observed in both groups. However, the peripheral blood CD19 levels were still low in both groups at 24 months after treatment. CONCLUSION: The patients in Group II showed excellent results similar to Group I. These results suggest that the low dose of rituximab (200 mg/body) is the sufficient dose in ABO-i kidney transplantation.