Monoclonal Antibody Therapy in Treating Patients With Non-Hodgkin's Lymphoma That Has Relapsed After High-Dose Chemotherapy and Autologous Stem Cell Transplantation

DISEASE CHARACTERISTICS: Diagnosis of relapsed B-cell non-Hodgkin's lymphoma (NHL) after high-dose chemotherapy and autologous stem cell transplantation Less than 25% bone marrow involvement with NHL as evidenced by unilateral or bilateral biopsy within the past 6 weeks Bone marrow biopsy should demonstrate 15-20% of cellular space occupied by normal hematopoiesis CD20 antigen expression in tumor tissue within the past year as evidenced by 1 of the following: Immunoperoxidase stains of tissue showing positive reactivity with L26 antibody Flow cytometry studies Measurable disease More than 2 cm bidimensionally No active CNS lymphoma No HIV- or AIDS-related lymphoma PATIENT CHARACTERISTICS: Age: 19 and over Performance status: WHO 0-2 Life expectancy: At least 3 months Hematopoietic: Absolute neutrophil count greater than 1,500/mm^3 Platelet count greater than 150,000/mm^3 No transfusion dependency Hepatic: Bilirubin less than 2.0 mg/dL SGOT or SGPT no greater than 2.5 times upper limit of normal (unless due to lymphomatous infiltration of the liver) Renal: Creatinine less than 2.0 mg/dL No active obstructive hydronephrosis Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception during and for 6 months after study therapy HIV negative No active infection requiring oral or IV antibiotics No human antimurine antibody positivity No other major medical problems PRIOR CONCURRENT THERAPY: Biologic therapy: See Disease Characteristics At least 4 weeks since prior growth factors At least 4 weeks since prior biologic therapy No dependency on hematopoietic growth factors (e.g., epoetin alfa, interleukin-11, filgrastim [G-CSF], or sargramostim [GM-CSF]) No prior radioimmunotherapy No other concurrent biologic therapy of any kind Chemotherapy: See Disease Characteristics At least 4 weeks since any prior cytotoxic chemotherapy (6 weeks for nitrosoureas) No prior fludarabine No concurrent chemotherapy Endocrine therapy: No concurrent steroids except as maintenance for non-cancerous disease Radiotherapy: See Biologic therapy At least 4 weeks since prior radiotherapy No prior pelvic radiotherapy No prior radiotherapy to more than 25% of estimated bone marrow reserve No concurrent external beam radiotherapy Surgery: Not specified Other: Recovered from all prior therapy At least 4 weeks since prior immunosuppressants No other concurrent investigational drugs No other concurrent anti-cancer therapy