High-dose intravenous rituximab for multifocal, monomorphic primary central nervous system posttransplant lymphoproliferative disorder.

Primary central nervous system (CNS) posttransplant lymphoproliferative disorder (PTLD) is a well-recognized but rare complication of solid organ transplantation. Most of these disorders are B-cell in origin and generally carry poor prognosis. Rituximab, an anti-CD20 monoclonal antibody, has been used effectively in patients with systemic PTLD. However, its role in primary CNS PTLD is doubtful because it does not cross blood-brain barrier efficiently (<5%). Also, mechanisms, by which rituximab operates are not optimally effective in CNS. Here, we describe a renal transplant patient with monomorphic, multifocal, CD20-positive, primary B-cell CNS PTLD, who was treated with high-dose intravenous rituximab given in dose-escalation protocol, which has been used effectively for the patients with chronic lymphocytic leukemia. At 1-year follow-up, magnetic resonance imaging (MRI) showed complete resolution. High-dose rituximab may have a role in highly selected patients with primary CNS PTLD.