B-cell depletion with rituximab as treatment for immune hemolytic anemia and chronic thrombocytopenia.

Rituximab reacts specifically with the CD20 antigen and induces B-cell depletion. This could interfere with the production of autoantibodies in some immune diseases. The objective of this study was to assess the effects of rituximab in autoimmune hemolytic anemia and thrombocytopenia.Seven patients (one with cold agglutinin disease, two with warm antibody autoimmune hemolytic anemia, four with chronic idiopathic thrombocytopenic purpura) previously refractory to conventional treatments were treated with weekly infusions of rituximab, 375 mg/m2, for 4 weeks. Only treatment with steroids, if strictly necessary, was allowed during the period of rituximab administration, but only patients who reached steroid suspension were considered responders. The pharmacokinetics of rituximab were quantified during therapy and the follow-up period.All patients had marked, even if temporary, B-cell depletion. Three patients, 1 with cold agglutinin disease (CAD) and 2 with chronic idiopathic thrombocytopenic purpura (ITP), had a complete hematologic response. In the patient with cold agglutinin disease a decrease in the agglutinin titer was observed. The hematologic improvement was prompt, appearing by the second or third infusion of rituximab. The response duration was CAD 96+, ITP 17+ and 13+ weeks in these 3 patients. Treatment tolerance was satisfactory and no infections or other late events were registered. Serum rituximab concentrations appeared to be similar to those calculated in a historical control group of patients with follicular non-Hodgkin's lymphoma who received rituximab as consolidation of response after first-line CHOP chemotherapy.Rituximab appeared to be active and safe in some patients with refractory autoimmune hemolytic anemia and thrombocytopenia. These results, along with data from literature, suggest that this agent may have a therapeutic role in autoimmune diseases.