OUTLINE: This is an open label study. Patients receive oral cyclophosphamide daily and rituximab (IDEC-C2B8 monoclonal antibody) IV on days 1, 8, 15, and 22 for the first 4-week course. Patients then receive oral cyclophosphamide daily and rituximab IV monthly until 2 months beyond maximum response. Patients are treated for at least 6 months but no more than 18 months in the absence of disease progression. Patients are followed every 3 months for 2 years, then every 6 months for the next 2 years, and then annually for up to 10 years.