CX₃CR1 is expressed by skin-infiltrating CD4⁺ T cells in AD patients. (A) CX₃CR1 expression by circulating CD4⁺ T cells. PBMCs from patients with AD or from healthy donors were analyzed by flow cytometry for CX₃CR1 expression. Data show frequency of CX₃CR1⁺ cells among CD4⁺ T cells in individual donors. (B) Cells from skin biopsies were characterized by surface and intracellular staining by flow cytometry. Left panel shows a representative FACS profile. Numbers indicate the mean ± SEM of the frequency of CX₃CR1⁺ among CD4⁺ T cells from n = 6 patients. Right panels show frequencies of cytokine-secreting CX₃CR1⁺ and CX₃CR1⁻ CD4⁺ T cells for each patient. Error bars indicate SEM.