Cell cytotoxicity by the combination of rexinoids and denileukin diftitox.

HUT78 cells (A), Sezary cells (B), and B-CLL cells (C) were incubated with rexinoids (a, alitretinoin (Panretin); b, bexarotene) for 48 hours and exposed to denileukin diftitox (Ontak) for 72 hours at various concentrations. Cytotoxicity was measured by MTT assay. Assays were performed in triplicate and data represent counts ± SEM.