Rituximab (anti-CD20 monoclonal antibody) for the treatment of patients with clonal lymphoproliferative disorders after orthotopic liver transplantation: a report of three cases

Background/Aims: Post-transplant lymphoproliferative disorders (PT-LPD) are a well-known complication of organ transplantation. Their incidence after liver transplantation in adults ranges from 1.8 to 4%. Reduction of immunosuppression led to remission in a few cases. Other treatments include chemotherapy, interferon alpha therapy and/or intravenous-immunoglobulins, or antiviral drugs. However, monoclonal antibodies directed against B-cell specific antigens have rarely been used in those patients. Our aim was to study the feasibility and efficacy of Rituximab, a new, promising human chimeric antibody that recognizes the CD20 antigen, for the treatment of patients with clonal lymphoproliferative disorders after orthotopic liver transplantation. Methods: Rituximab (IDEC-C2HB8; Roche Laboratories, Neuilly-sur-Seine, France) was administered at a 375 mg/m2 dose on days 1, 8, 15, and 22, in an outpatient setting, in three patients with PT-LPD. The tumor was classified as polymorphic PT-LPD in two cases and PT-LPD with features of large cell lymphoma in one case. All the tumors expressed the CD20 antigen and were EBV-related, and the clonality was confirmed in all three cases. The 4 injections of the anti-CD20 monoclonal antibody were associated with reduced immunosuppression in the three patient. Results: The treatment with Rituximab was well tolerated without any side effects. The two patients with polymorphic PT-LPDs underwent rapid complete remission, whereas the treatment modalities were ineffective in the patient with the large-cell non-Hodgkinlymphoma. Conclusion: These results must be confirmed in a larger cohort of liver transplant recipients suffering from lymphoproliferation. However, they indicate rapid efficiency of Rituximab in association with reduced immunosuppression in these disorders.