CCR4-CAR T cells can lyse and respond to patient–derived primary CTCL cells. (A) Cytokine production by CCR4-CAR T cells upon stimulation with primary CTCL cells. Cytokine production of CAR T cells at 6 hours after stimulation was analyzed by intracellular staining and FCM. The gates represent a positive population of the indicated cytokines in CAR-positive cells. (B) Lytic activity of CCR4-CAR T cells against primary CTCL cells. The killing activity of CAR T cells against each cell at 4 hours of coculture was analyzed by a ⁵¹Cr release assay. Dots and bars represent the mean and standard deviation from a single donor experiment (technical triplicate).