Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed chronic lymphocytic leukemia OR small lymphocytic lymphoma

- Stage III-IV OR

- Stage I-II, if determined to have disease progression evidenced by 1 of the
following characteristics:

- Rapid doubling of peripheral lymphocyte count

- Progressive lymphadenopathy

- Progressive splenomegaly

- B symptoms

- Grade 2 or 3 fatigue

- CD23+ disease

- Progressive disease after at least 1 prior chemotherapy course

PATIENT CHARACTERISTICS:

Age

- 18 and over

Performance status

- WHO 0-2

Life expectancy

- At least 6 months

Hematopoietic

- Platelet count at least 50,000/mm^3

Hepatic

- Bilirubin no greater than 2.0 mg/dL

- AST/ALT no greater than 1.5 times upper limit of normal (ULN)

Renal

- Creatinine no greater than 1.5 times ULN

Cardiovascular

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

- No myocardial infarction within the past 6 months

- No unstable arrhythmia

- No evidence of ischemia on EKG within the past 14 days

Pulmonary

- FEV_1 at least 60% of predicted

- DLCO at least 55% of predicted

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 secondary malignancy requiring active treatment (except hormonal therapy)

- No serious nonmalignant disease that would preclude study participation

- No active uncontrolled bacterial, viral, or fungal infection

- No clinically active autoimmune disease

PRIOR CONCURRENT THERAPY:

Biologic therapy

- More than 4 weeks since prior anticancer biologic therapy

- More than 4 weeks since prior anticancer radioimmunotherapy

- No prior exposure to IDEC-152 or anti-CD23 antibodies

Chemotherapy

- See Disease Characteristics

- More than 4 weeks since prior anticancer chemotherapy

Endocrine therapy

- Concurrent hormonal therapy allowed for second malignancy

Radiotherapy

- More than 4 weeks since prior anticancer radiotherapy

Surgery

- More than 4 weeks since prior major surgery (except for diagnostic surgery)

Other

- More than 4 weeks since prior anticancer investigational therapy

- No other concurrent anticancer therapy