IL2 and primary cutaneous T-cell non-Hodgkin lymphoma: To date, relatively few ligand-based targeted proteins have been FDA approved, the most prominent being denileukin diftitox (Ontak), a fusion protein comprising the cytokine IL-2 fused to diphtheria toxin (DT) for treatment against CD25-positive cutaneous T-cell lymphoma (CTCL) [21].