DMF causes cell death in primary CTCL cells and CTCL cell lines. (A) Specific cell death in primary CD4⁺ cells isolated from 10 healthy volunteers (control) and 10 patients with Sézary syndrome (patient) upon treatment with 30 µM DMF (left) or 30 µM MMF (right) for 48 hours. Triangles, single samples; gray bars, median. (B) Specific cell death rates in primary CD4⁺ cells isolated from 10 healthy volunteers (control) and 10 patients with Sézary syndrome (patient) upon treatment with different concentrations of DMF for 48 hours. (C) Specific cell death rates in J16, HH, and SeAx cells upon treatment with different concentrations of DMF solubilized in dimethyl sulfoxide for 24 hours (n = 4, each). (D) Decrease in tetramethylrhodamine ethyl ester (TMRE) mean fluorescence intensity in J16, HH, and SeAx cells upon treatment with either 30 µM DMF or MMF or 10 µM CCCP for 24 hours (n = 4, each). *P < .05. (E) Western blot analysis of caspase 3 cleavage in HH (left) and SeAx (right) cells after treatment with 50 µM DMF for the indicated time points. (F) Single cell gel electrophoresis of HH (left panels) and SeAx (right panels) cell upon treatment with either vehicle or 50 µM DMF for 8 hours.