DISEASE CHARACTERISTICS: Histologically confirmed stage II-IV low-grade, mantle cell, or follicular B-cell lymphoma Stage I disease is eligible only if radiotherapy is not considered feasible due to location of disease or previous radiation treatments No chronic lymphocytic lymphoma No small lymphocytic lymphoma with lymphocyte count greater than 5,000/mm3 Must be either first-line therapy or no more than 4 relapses after standard therapies, including chemotherapy, radiotherapy, autologous bone marrow transplantation, and/or immunotherapy Eligible if refractory to first treatment with a standard therapy Patients refractory to autologous bone marrow transplantation (ABMT) or relapsed after ABMT are eligible Patients with low-grade or follicular lymphoma must have failed at least one chemotherapy regimen Patients with mantle cell lymphoma are eligible even if no prior treatment Bidimensionally measurable disease Demonstrable monoclonal CD20-positive B-cell population in lymph nodes or bone marrow No prior diagnosis of intermediate or high-grade non-Hodgkin's lymphoma No CNS, pericardial, pleural, or peritoneal involvement by lymphoma No AIDS-related lymphoma No pleural effusion No ascites A new classification scheme for adult non-Hodgkin's lymphoma has been adopted by PDQ. The terminology of "indolent" or "aggressive" lymphoma will replace the former terminology of "low", "intermediate", or "high" grade lymphoma. However, this protocol uses the former terminology.