DISEASE CHARACTERISTICS:

• Histologically confirmed B-cell non-Hodgkin's lymphoma OR acute lymphoblastic leukemia

  • CD20+ (confirmed by flow cytometry of tumor tissue, involved marrow, or CD20 immunostaining)

  • The following histologies are generally CD20+ and are eligible:

    • Diffuse large B-cell lymphoma, mediastinal (thymic) large B-cell lymphoma, or follicular lymphoma, grade III (rare), documented by flow cytometry or appropriate immunohistochemistry, any stage
    • Burkitt's lymphoma or atypical Burkitt's/Burkitt-like lymphoma, any stage
    • B-cell acute lymphoblastic leukemia, with FABL3 morphology and/or demonstration of surface immunoglobin by flow cytometry
    • Atypical precursor B-cell lymphoblastic lymphoma or other unusual histologies that are CD20+
• Measurable disease by clinical, radiographic, or histologic criteria
• Must be in first or later recurrence or have disease that is primarily refractory to conventional therapy
• No isolated CNS disease

PATIENT CHARACTERISTICS:

Age

• 21 or under when diagnosed with recurrent or refractory disease

Performance status

• ECOG 0-2

Life expectancy

• At least 2 months

Hematopoietic

• Absolute neutrophil count ≥ 1,000/mm^3*
• Platelet count ≥ 100,000/mm^3 (transfusion independent)*
• Hemoglobin ≥ 10.0 g/dL (RBC transfusion allowed)* NOTE: *Patients with B-cell acute lymphoblastic leukemia and lymphoma involving bone marrow who have granulocytopenia, anemia, and/or thrombocytopenia are eligible but are not evaluable for hematologic toxicity

Hepatic

• Bilirubin ≤ 1.5 times normal
• ALT < 2.5 times normal

Renal

• No chronic renal insufficiency

  • Renal insufficiency allowed provided it is secondary to tumor lysis syndrome

Other

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception during and for 3 months after study treatment
• HIV negative
• No active uncontrolled infection
• Seizure disorder allowed if well controlled with anticonvulsants
• No CNS toxicity greater than grade II

PRIOR CONCURRENT THERAPY:

Biologic therapy

• At least 24 hours since prior growth factor(s)
• At least 60 days since prior biologic (antineoplastic) therapy

• Prior stem cell transplantation allowed provided the following criteria are met:

  • More than 60 days since transplantation
  • Hematopoietic lab value requirements are met (See Hematopoietic)
  • No evidence of graft-versus-host disease (if post-allogeneic transplantation)
• Prior monoclonal antibody therapy allowed (including rituximab)
• No other concurrent immunomodulating agents

Chemotherapy

• More than 2 weeks since prior myelosuppressive chemotherapy (4 weeks for nitrosoureas)
• No other concurrent chemotherapy

Endocrine therapy

• No concurrent steroids (except for rituximab infusion-related symptoms)

Radiotherapy

• At least 2 weeks since prior local palliative radiotherapy (small port)
• At least 6 weeks since prior substantial bone marrow radiotherapy
• At least 6 months since prior craniospinal radiotherapy or radiotherapy to 50% or more of the pelvis
• Concurrent radiotherapy to localized painful, airway-compromising, or other acute organ-threatening lesions allowed provided at least 1 measurable lesion is not irradiated

Surgery

• Not specified

Other

• Recovered from prior therapy
• No concurrent participation in another phase II study