Successful treatment with the monoclonal antibody rituximab in two children with refractory autoimmune thrombocytopenia

Rituximab is a chimeric monoclonal antibody directed against normal and malignant mature B-lymphocytes and results in prolonged and severe B-cell depletion. Recently, rituximab has been successfully used in adult and paediatric disorders of B-lymphocytes such as autoimmune haemolytic anaemia and Werlhof disease. We report on two children with chronic immune thrombocytopenic purpura (ITP) refractory to steroids and immunoglobulins who achieved complete normalisation of their platelet counts after treatment with rituximab, 375 mg/m(2) given weekly in four doses. In both cases the B-lymphocyte count dropped to zero after the second dose of rituximab and an unsupported platelet count >100x10(9)/l was achieved during treatment. Six and 12 months after treatment, both patients remain well with normal platelet counts. Conclusion: this report supports the concept that rituximab may also be a valuable therapeutic option in children with chronic immune thrombocytopenic purpura refractory to standard treatment. Controlled clinical trials are needed to evaluate the efficacy and long-term side-effects of rituximab in this group of patients.