CCR4 expression decreases in a subset of patients after mogamulizumab treatment. (A) Total duration of treatment with mogamulizumab and best treatment responses. (B) CCR4 IHC expression pre- and posttreatment with mogamulizumab. Bars indicate mean H score. Lines connect paired samples from the same patient. (C-D) MFI of CCR4 by flow cytometry before and after treatment using 2 CCR4 antibodies: 1G1 (C) and KM2160 (D). *P < .05 by Mann-Whitney U test. H score, percentage of the CCR4⁺ cells among all cells in the infiltrate x intensity of expression 0-3+.