Inclusion Criteria:

- Relapsed or refractory B-Cell NHL

- Histological documentation of diffuse large B-cell lymphoma, follicular lymphoma
(grade 1, 2, or 3), small lymphocytic lymphoma or transformed B-Cell lymphoma.

- Bi-dimensionally measurable disease with at least one lymph node or tumor mass
measuring > or equal to 4 cm2

- ECOG performance status less than or equal to 2.

- Failure to respond or progression of disease after 2 or more prior treatment
regimens; this may include high dose therapy (HDT) with stem cell transplantation
(SCT). Patients with prior HDT plus SCT will be considered as having "diminished bone
marrow reserve"

- At least 18 years of age

- At least 3 weeks from last anti-lymphoma therapy

- Mild to moderate cytopenia defined as any of the following:

- ANC > or equal to 1,000/microL and < 1,500/microL off growth factors

- WBC counts > or equal to 2,000/microL and < 4,000/microL off growth factors or

- Platelet count > or equal to 40,000/microL (25,000/microL if thrombocytopenia is
secondary to marrow involvement by lymphoma) and < 150,000/microL.

- Acceptable organ function defined as all of the following:

- Bilirubin < or equal to 1.5 times the upper limit of normal (ULN)

- SGOT (AST) and SGPT (ALT) < or equal to 2 times the ULN.

- Serum creatinine < 2 times ULN.

- Serum albumin > or equal to 3.0 g/dL

- Female patient of childbearing potential must have a negative pregnancy test within
seven days prior to study drug administration, and must agree to use an effective
means of contraception throughout the study.

- Life expectancy of at least 16 weeks.

- Patients must have reviewed, signed and dated a witnessed informed consent document
that has been approved by the IRB of each participating center.

Exclusion Criteria:

- Less than 6 months from prior allogeneic stem cell transplant and/or patient with
active graft versus host disease (GVHD) Grade > or equal to 2.

- Prior history of veno-occlusive disease of the liver.

- Inability to comply with protocol requirements of this study for intravenous
administration of ONTAK.

- Pregnant women or lactating women who are breastfeeding or women planning to become
pregnant during the treatment period.

- Serious intercurrent medical illnesses or active infections that, in the
investigators opinion, might interfere with the interpretation of the study safety
data or compromise the patients ability to carry out the treatment program.

- Known history of seropositivity for HIV or chronic hepatitis (testing for HIV is not
required).

- Known hypersensitivity to ONTAK or any of its components: diptheria toxin,
interleukin-2 or excipients.

- Experimental therapy within 4 weeks prior to study entry.

- Patients diagnosed with congestive heart failure, NYHA Class III or IV, ventricular
tachycardia, fibrillation, or a history of myocardial infarction in the 12 months
prior to study entry.

- Any prior radiation therapy within four weeks of enrollment, or prior radiation
therapy to the only site of evaluable disease unless disease progression has occurred
in that site.

- Patients on concurrent corticosteroids as treatment for NHL. The use of tapering
doses or low doses of corticosteroids for resolving GVHD, or the use of
corticosteroids as premedication prior to ONTAK or as a transient treatment for
hypersensitivity reactions is permitted as necessary.

- History of prior malignancy within the preceding 5 years, except for successfully
treated cervical carcinoma in situ or basal cell carcinoma.