Altered circulating memory T cells in vitiligo cases followed NB‐UVB therapy
Fuquan Lin, Xiukun Sun, Jiehao Lei, Aie Xu
Abstract
Abstract Background Vitiligo represents a commonly diagnosed autoimmune disease caused by the depletion of epidermal melanocytes. Many subsets of T cells contribute to vitiligo pathogenesis, including resident and circulating memory T cells. Objectives To analyze the amounts of CD4 + and CD8 + memory T‐cell subsets in peripheral blood specimens from vitiligo patients and alterations caused by narrowband ultraviolet B (NB‐UVB) phototherapy. Methods Circulating CD4 + and CD8 + central memory T (T CM ) and effector memory T (T EM ) cell frequencies in 33 patients with non‐segmental vitiligo and 16 healthy donors were evaluated by flow cytometry. Related chemokine levels were also detected. Results Peripheral blood CD4 + T CM and CD8 + T CM counts were markedly reduced in vitiligo cases while they were higher in active vitiligo compared with stable vitiligo cases. Circulating CD8 + T CM frequency in vitiligo was closely related to disease duration. Interestingly, CD4 + T CM and CD8 + T CM frequencies, alongside CXCL9 and CXCL10 amounts in peripheral blood of patients with vitiligo, were significantly decreased after NB‐UVB phototherapy. Conclusions Decreased frequencies of circulating CD4 + T CM and CD8 + T CM by NB‐UVB suggest a possible immunosuppressive effect of phototherapy. The chemokines CXCL9 and CXCL10 are the bridge between circulating and skin resident memory T cells. NB‐UVB blocks the homing of circulating memory T cells into vitiligo lesions by down‐regulating CXCL9 and CXCL10. Targeting the above proteins could provide novel, durable treatment options to cure and prevent flares of this disease.