Refractory acute kidney transplant rejection with CD20 graft infiltrates and successful therapy with rituximab.

Acute rejection is an expected event after transplantation and has been associated with poor long-term kidney transplant outcome. The presence of B cells in the kidney graft with acute rejection is thought to be an omnious sign, as it has been associated with poor graft outcome. There is no definitive treatment for acute rejection with B cells in the graft. Rituximab, a humanized monoclonal antibody against CD20, has been used in the treatment of B cell lymphoma. We present the case of a 49-yr-old Caucasian male with early acute kidney allograft rejection that was refractory to high doses of steroids and rabbit anti-thymocyte globulin (thymoglobulin). Repeat renal biopsy revealed T cell and B cells in the kidney graft and responded to the combination of rituximab and muromonab (a mouse monoclonal antibody to CD3 receptor). Over 9 months post-transplant, the patient remains rejection free with a serum creatinine of 1.7 mg/dL.