Inclusion Criteria:

• Persistent or recurrent cutaneous T-cell lymphoma (CTCL) Stage IB-IVA as defined by TNM staging.
• Pathologic proven diagnosis (cytologically confirmed) of CTCL documented in patient history.
• Preserved organ function: Creatinine and/or Liver Function levels <1.5 times institutional upper limits of normal (ULN).
• Adequate liver function as indicated by bilirubin < or equal to 1.5 times ULN, ALT < or equal to 2 times ULN, AST < or equal to 2 times ULN.
• Albumin >3.0 g/dL
• Adequate renal function as indicated by SCr < or equal to 2.5 mg/dl.
• ECOG performance status between 0-2.
• Women of childbearing potential should be screened for pregnancy prior to treatment and utilize effective contraceptive methods (e.g. barrier) during treatment period.
• Patients over the age of 18 who are willing and able to provide Informed Consent.

Exclusion Criteria:

• Pathology consistent with peripheral T-cell lymphoma.
• Stage IVB (visceral involvement with CTCL, other than lymph node involvement).
• History of Human Immunodeficiency Virus (HIV), Hepatitis B or Hepatitis C infection.
• Patients who are pregnant or breast feeding.
• Allergy to or have history of allergy to diphtheria toxin or IL-2.
• Previous ONTAK® usage.
• Unstable cardiovascular disease.
• Patients who have received systemic or topical antineoplastic therapy or investigational medications within past 14 days. Exception: Clear evidence of disease progression requiring immediate intervention and in the absence of ongoing toxicity from prior therapy.
• Ongoing deep vein thrombosis or a diagnosis of deep vein thrombosis less than 3 months prior to protocol enrollment.