RESUMO
BACKGROUND: It is widely believed that an imbalance between activated CD8(+) T cells and regulatory T cells (Tregs) exists in patients with vitiligo. Although there is evidence that narrow band ultraviolet (NB-UVB) irradiation can induce Tregs' number and activity, but up to our knowledge, none of the published studies involved the possible effect of NB-UVB on Tregs in vitiligo. OBJECTIVE: To evaluate the effect of NB-UVB on circulating CD4(+) CD25(high) FoxP3(+) regulatory T cells (FoxP3(+) Tregs) in vitiligo. METHODS: This prospective analytic study included 20 patients with active non-segmental vitiligo and 20 healthy controls. The patients were exposed to NB-UVB therapy three times per week for 30 sessions. Blood sampling before and after NB-UVB phototherapy was done to evaluate circulating CD4(+) CD25(high) Tregs and Foxp3(+) Tregs. RESULTS: The CD4(+) CD25(high) Tregs% and FoxP3(+) Tregs% were significantly higher in vitiligo patients compared with controls. NB-UVB therapy decreased both of them in patients, but they did not reach those of controls. Each of circulating CD4(+) CD25(high) Tregs% and FoxP3(+) Tregs% didn't correlate with either extent or activity of vitiligo before or after NB-UVB. CONCLUSION: Tregs functional defect is probably having an impact on NSV. NB-UVB may improve the function of Tregs. Understanding the mechanisms through which NB-UVB exert its effect on reducing the number of circulating Tregs would help open up the paths for future therapeutic options.
