Inclusion Criteria:

- Patients must fulfill the criteria for the diagnosis of intermediate-risk B-cell CLL
or high-risk B-cell CLL

- The bone marrow aspirate must demonstrate that greater than or equal to 30% of all
nucleated cells are lymphoid.

- Patients must have evidence that their leukemic lymphocytes express the CD20 antigen.

- Patients must have been previously treated with chemotherapy or biologic therapy and
have progressed on, failed to achieve an objective response (CR or partial response
[PR]) on, or progressed after completion of last therapy. Patients must have
received at least one therapy containing a purine nucleoside analogue. Patients must
not have received more than 4 prior therapies. This includes both chemotherapy and
biologic therapy.

- Patients must have an absolute granulocyte count >500 cells/mm3 and a platelet count
of either >100,000 cells/mm3 (Cohort A) or a platelet count of 75,000-100,000
cells/mm3 deemed to be secondary to CLL by the investigator, (Cohort B) within 14
days of study entry. These blood counts must be sustained for 4 weeks without
support of hematopoietic cytokines or transfusion of blood products.

- Patients must have a Karnofsky Performance status of at least 60% and an anticipated
survival of at least 3 months.

- Patients must have adequate renal function (defined as serum creatinine <1.5 x upper
limit of normal [ULN]) and hepatic function (defined as total bilirubin <1.5 x ULN
and AST <3 x ULN) within 14 days of study entry. For patients with autoimmune
hemolytic anemia, the bilirubin must be less than or equal to 8 x ULN.

Exclusion Criteria:

- Patients who have received prior therapy with cytotoxic chemotherapy or
immunosuppressants (with the exception of maintenance prednisone therapy not to
exceed a dose of 20 mg/day for autoimmune hemolysis only) within FOUR weeks prior to
study entry (6 weeks for nitrosourea compounds) or who exhibit persistent clinical
evidence of toxicity. The prednisone must have been started more than 4 weeks prior
to study entry.

- Patients with progressive disease within 1 year of irradiation arising in a field
that has been previously irradiated with >3500 cGy.

- Patients with New York Heart Association class III or IV heart disease or other
serious illness that would preclude evaluation.

- Patients with active obstructive hydronephrosis.

- Patients with prior malignancy other than CLL, except for adequately treated skin
cancer, in situ cervical cancer, or other cancer for which the patient has been
disease-free for 5 years. Patients who have been disease-free of another cancer for
greater than 5 years must be carefully assessed at the time of study entry to rule
out recurrent disease.

- Patients with known HIV infection.

- Patients who are pregnant or nursing. Patients of childbearing potential must
undergo a serum pregnancy test within 7 days prior to study entry. Males and females
must agree to use a contraceptive method from enrollment to 6 months after receiving
Iodine-131 Anti-B1 Antibody.

- Patients who are concurrently receiving either approved or non-approved (through
another protocol) anti-cancer drugs or biologics.

- Patients with evidence of active infection requiring intravenous treatment with
anti-infectives.

- Patients known to be HAMA positive.