LAUSR

CLS: capillary leak syndrome CR: complete remission CTCL: cutaneous T-cell lymphoma DD: denileukin diftitox pcALCL: primary cutaneous anaplastic large-cell lymphoma Treg: T-regulatory cell INTRODUCTION Denileukin diftitox (DD) is a recombinant fusion protein that consists of the interleukin-2 molecule conjugated to the catalytic domain of diphtheria toxin. It targets cells expressing the high-affinity interleukin-2 receptor, such as activated T lymphocytes in cutaneous T-cell lymphoma (CTCL). After binding to the interleukin-2 receptor, DD undergoes endocytosis followed by release of diphtheria toxin, which inhibits protein synthesis and induces subsequent cell apoptosis. DD was approved by the US Food and Drug Administration in 1999 for the treatment of persistent or recurrent CTCL. However, the pivotal trial leading to the drug’s approval only included patients with mycosis fungoides or S ezary syndrome. Although its clinical activity in other forms of CTCL remains unclear, DD may be useful for primary cutaneous anaplastic large-cell lymphoma (pcALCL). We report the case of a patient with recurrent pcALCL who has maintained complete remission (CR) for 13 years after treatment with DD.