Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed B-cell diffuse large cell lymphoma

- L-26 positive (i.e., CD20-positive)

- Failed 2 prior chemotherapy regimens

- At least 1 measurable lesion

- At least 2 cm by physical exam or CT scan

- No active lymphomatous meningitis or other CNS involvement by lymphoma

- No significant marrow involvement (i.e., more than 20% of hematopoietic marrow
elements from iliac crest biopsy)

PATIENT CHARACTERISTICS:

Age:

- 18 and over

Performance status:

- Karnofsky 60-100%

Life expectancy:

- At least 3 months

Hematopoietic:

- WBC at least 3,500/mm3

- Granulocyte count at least 1,500/mm3

- Platelet count at least 125,000/mm3

Hepatic:

- Bilirubin no greater than 2 times upper limit of normal (ULN)

- AST/ALT no greater than 3 times ULN

- Alkaline phosphatase no greater than 3 times ULN

Renal:

- Creatinine no greater than 2 times ULN

Cardiovascular:

- No electrocardial evidence of Q-wave myocardial infarction within the past 6 months

- No congestive heart failure

- No New York Heart Association class III or IV heart disease

Other:

- HIV negative

- Negative human anti-mouse antibodies (i.e., less than 74 ng/mL)

- No known antiplatelet antibodies

- No other malignancy except basal cell skin cancer or carcinoma in situ of the cervix

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy:

- No prior bone marrow or peripheral blood stem cell transplantation

- No prior radioimmunotherapy

- Prior unlabeled monoclonal antibody therapy allowed

- At least 120 hours since prior filgrastim (G-CSF) or sargramostim (GM-CSF)

- At least 1 month since prior epoetin alfa

Chemotherapy:

- See Disease Characteristics

- No concurrent chemotherapy

Endocrine therapy:

- Not specified

Radiotherapy:

- See Biologic therapy

- No prior total body irradiation (TBI)

- At least 6 months since prior radiotherapy (over 3,00 cGy) to more than 20% of
marrow-bearing space (i.e., pelvis and spine)

- No concurrent large-field radiotherapy (i.e., TBI, hemibody radiation, or radiation
fields that include more than 20% of active marrow to a dose of over 3,000 cGy)

- Concurrent localized radiotherapy is allowed to current or impending serious
complication (e.g., bronchial obstruction by hilar lymph nodes or impending fracture
due to lytic bone lesions)

Surgery:

- Not specified

Other:

- Recovered from prior anti-lymphoma therapy

- At least 120 hours since prior whole blood or platelet transfusion

- No concurrent anticoagulants or antiplatelet drugs

- No concurrent medications known to inhibit blood clotting or platelet aggregation
(e.g., aspirin)