Interleukin-2 fusion toxin is produced by replacing the receptor binding domain of diphtheria toxin with sequences from interleukin-2, thus producing specific cytotoxicity in cells expressing the interleukin-2 receptor. The interleukin-2 fusion toxin denileukin diftitox is used in the treatment of cutaneous T-cell lymphoma. The related compound DAB⁴⁸⁶ interleukin-2 has also been investigated in a variety of disorders.