Inclusion Criteria

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