IL2 and primary cutaneous T-cell non-Hodgkin lymphoma: Denileukin diftitox (rIL-2/diphtheria toxin [DTx]), a recombinant fusion protein composed of the membrane-translocating and cytotoxic domains of diphtheria toxin (Met1-Thr387)-His and human interleukin 2 (Ala1-Thr133), is FDA-approved for the treatment of cutaneous T cell lymphoma [29].