Rituximab is an antibody made in a laboratory. It binds to lymphoma cells and kills them. Treatment of recurrent B-cell lymphoma with rituximab may delay or prevent relapses. A total of 166 patients with recurrent B-cell lymphoma were given intravenous rituximab once a week for 4 weeks. The patients' tumors were measured before and after treatment. Ten patients had a complete response and 70 patients had a partial response to rituximab. The median duration of response was 11.2 months.