IL2 and primary cutaneous T-cell non-Hodgkin lymphoma: The resulting chimeric molecules were named immunotoxins (ITs) and, in 1999, Ontak, an immunotoxin consisting of human IL2 conjugated with a truncated form of diphtheria toxin (DT), was the first to be approved by the US Food and Drug Administration (FDA) for the treatment of cutaneous T-cell lymphoma (CTCL).