DISEASE CHARACTERISTICS:

• Diagnosis of B-cell chronic lymphocytic leukemia (CLL) or small B-cell lymphocytic lymphoma (SLL) with the following:

  • Lymph node biopsy interpreted as SLL or consistent with CLL or all of the following:

    • Peripheral lymphocyte count greater than 5,000/mm^3 with small to moderate peripheral lymphocytes and no more than 55% prolymphocytes
    • Bone marrow aspirate containing at least 30% lymphoid cells

    • Immunophenotypic evaluation of peripheral blood lymphocytes demonstrating monoclonality of B lymphocytes with all of the following:

      • CD19 or CD20 coexpressed with CD5 antigen in the absence of other pan-T- cell markers (e.g., CD2 or CD3)
      • Expression of CD23 on CLL cells or Dim B-cell expression of kappa or lambda light chains

• Measurable disease with any of the following:

  • 1 or more lymph nodes at least 1.5 cm by CT scan
  • Splenomegaly by CT scan
  • Peripheral lymphocyte count greater than 5,000/mm3 with coexpression of CD5 and B-cell markers
  • Bone marrow aspirate with at least 30% lymphoid cells
• No mantle cell lymphoma

PATIENT CHARACTERISTICS:

Age

• 18 and over

Performance status

• ECOG 0-2

Life expectancy

• At least 2 years

Hematopoietic

• See Disease Characteristics
• No immune thrombocytopenia
• No hemolytic anemia

Hepatic

• Bilirubin no greater than 3 times upper limit of normal (ULN)
• SGOT no greater than 3 times ULN (unless due to hemolysis or CLL)
• No hepatitis

Renal

• Creatinine no greater than 1.5 times ULN

Cardiovascular

• No cardiac dysfunction
• No New York Heart Association class III or IV heart disease
• No myocardial infarction within the past month

Other

• HIV negative
• No active acute or chronic infection
• No immunosuppressive diseases
• No autoimmune disorder
• No secondary malignancy that is projected to limit life expectancy
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy

• See Chemotherapy
• No prior rituximab
• At least 4 weeks since prior biologic therapy

Chemotherapy

• At least 4 weeks since prior chemotherapy
• No prior combination chemotherapy and rituximab or other antibody therapy
• No prior combination chemotherapy comprising an alkylating agent and a purine nucleoside analog (i.e., cyclophosphamide or chlorambucil in combination with fludarabine, cladribine, or pentostatin)
• No prior pentostatin

Endocrine therapy

• At least 4 weeks since prior corticosteroids
• No concurrent supra-physiologic doses of corticosteroids

Radiotherapy

• At least 4 weeks since prior radiotherapy

Surgery

• At least 4 weeks since prior major surgery

Other

• No concurrent immunosuppressive therapy (e.g., cyclosporine)