Inclusion Criteria:

- Patients must have serum antibodies directed to Human T-lymphotropic Virus Type 1
(HTLV-1).

- All patients must have a histologically confirmed diagnosis of adult T- cell
leukemia/lymphoma and more than 10% of the malignant cells must express CD52 and
CD25.

- All stages of Tac-expressing adult T-cell leukemia except smoldering are eligible:
patients with chronic, lymphoma or acute Acute T-cell leukemia/lymphoma (ATL) are
eligible.

- Patients must have measurable disease. All patients with greater than 10% abnormal
(i.e. Tac homogeneous strongly expressing) peripheral blood mononuclear cell (PBMC)in
the peripheral blood will be deemed to have measurable disease.

- The patient must have a granulocyte count of at least 100/mm(3) and a platelet count
of greater than or equal to 50,000/mm(3).

- Patients must have a creatinine of less than 3.0 mg/dl.

- Omission of cytotoxic chemotherapy for ATL for 3 weeks prior to entry into the trial
is required. However patients receiving a stable dose of corticosteroids for at least
three to four weeks without evidence of tumor response will be eligible.

- Patients must have a life expectancy of greater than 2 months.

- Eligible patients must be greater than or equal to 18 years old. There is no upper
age limit.

- Patients must have serum glutamic oxaloacetic transaminase (SGOT) and serum glutamic
pyruvic transaminase (SGPT) value less than or equal to 2.5-fold greater than the
upper limit of normal and bilirubin less than or equal to 3.0/dl. If a liver function
test is judged to be elevated due to the underlying ATL, this parameter will be
considered an unevaluable parameter for toxicity determinations.

- Patients must be able to understand and sign an Informed Consent form.

- All patients must use adequate contraception during participation in this trial and
for three months after completing therapy.

Exclusion Criteria:

- Patients with symptomatic leukemic meningitis will be excluded. However patients that
have both ATL and another HTLV-1-associated disease, tropical spastic paraparesis
(TSP) will be included.

- Pregnant and nursing patients are not eligible for the study. Because the effects of
CAMPATH-1H on the developing fetus are unknown pregnant women will be excluded.
Breast-feeding in patients with HTLV-1 infection is contraindicated because of the
risk of transmission of the virus to the child. In addition, CAMPATH-1H may be
present in breast milk and produce adverse events in the breast-feeding child.

- Human immunodeficiency virus (HIV) positive patients are excluded from the study.
CAMPATH-1H may produce a different pattern of toxicities in patients with HIV
infection and in addition the depletion of T cells produced by CAMPATH-1H may have
adverse effects on HIV positive individuals.

- Patients with smoldering ATL are excluded.

- Patients with previously received Campath-1GH are ineligible.