The study was an open-label trial; those assigned to rituximab received a 1 g infusion of rituximab followed by an identical dose 2 weeks later. Premedication with corticosteroids (10 mg dexamethasone intravenously) was also given 30 min prior to the first infusion of each series of rituximab. They received an identical 2 g course of rituximab 6 months later. Subjects were assessed at least every 3 months or as needed for clinical events. This assessment included physical examination, a questionnaire for adverse events, and measurement of routine hematology, serum chemistry, timed urine protein excretion, and for those assigned to rituximab, B-cell subsets. Follow-up was considered complete at 12 months.