DISEASE CHARACTERISTICS:

• Histologically confirmed chronic lymphocytic leukemia or prolymphocytic leukemia:
• Failed prior standard chemotherapy and treatment is medically indicated as evidenced by the following:
• Progressive disease-related symptoms
• Progressive cytopenias due to marrow involvement
• Progressive or painful splenomegaly or adenopathy
• Rapidly increasing lymphocytosis
• Autoimmune hemolytic anemia or thrombocytopenia
• Increased frequency of infections OR
• Confirmed CD22+ B-cell indolent non-Hodgkin's lymphoma
• Stages II-IV that have failed at least 1 prior standard therapy and treatment is medically indicated
• No patients whose serum neutralizes BL22 or PE38 in tissue culture, due to antitoxin or antimouse-IgG antibodies
• No central nervous system disease requiring treatment
• If the patient is non-leukemic, the absolute neutrophil count must be greater than 1,000/mm3 and the platelet count greater than 40,000/mm3

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Performance status:

• Karnofsky 60-100%

Life expectancy:

• More than 6 months

Hematopoietic:

• See Disease Characteristics

Hepatic:

• ALT and AST less than 5 times upper limit of normal

Renal:

• Adequate renal function

Pulmonary:

• Adequate pulmonary function

Other:

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception
• HIV negative

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• Prior bone marrow transplantation allowed
• At least 3 weeks since prior interferon for malignancy

Chemotherapy:

• See Disease Characteristics
• At least 3 weeks since prior cytotoxic chemotherapy for malignancy

Endocrine therapy:

• Not specified

Radiotherapy:

• At least 3 weeks since prior radiotherapy for malignancy

Surgery:

• Not specified

Other:

• At least 3 weeks since prior retinoids
• At least 3 weeks since prior systemic therapy for cancer