Objective To evaluate the effect of human dermal mesenchymal stem cells (DMSCs) on the expression and secretion of interleukin (IL)-13 by perilesional CD8+ T lymphocytes from patients with vitiligo.Methods Tissue specimens were obtained from the perilesional region of six patients with active vitiligo,and CD8+ T lymphocytes were isolated from both the tissue specimens and peripheral blood of these patients.DMSCs and melanocytes were obtained from the foreskin tissue of healthy males.The 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium,inner salt (MTS) assay was performed to estimate the effect of different concentrations of recombinant IL-13 on the proliferation of melanocytes,reverse transcripition-PCR and Western blotting to detect the mRNA and protein expressions of IL-13 in perilesional and peripheral blood CD8+ T lymphocytes respectively,real-time quantitative reverse transcription (RT)-PCR and enzyme-linked immunosorbent assay (ELISA) to detect the IL-13 mRNA expression in,and IL-13 protein expression in the culture supematant of,CD8+ T lymphocytes before and after coculture with DMSCs,respectively.Statistical analysis was done by t test.Results No obvious changes were observed in the proliferation of melanocytes treated with different concentrations (10,50,100,250,500 μg/L) of recombinant IL-13 for various durations (24,48,72 and 96 hours)compared with untreated melanocytes (all P ＞ 0.05).Both perilesional and peripheral blood CD8+ T lymphocytes expressed IL-13,and the expression was stronger in perilesional than in peripheral blood CD8+ T lymphocytes.A significant decrease was noted in IL-13 mRNA expression (0.100 0 ± 0.002 4 vs.0.383 2 ± 0.018 7,P ＜ 0.05) and protein level in the culture supernatant ((1 509.62 ± 48.44) ng/L vs.(5 507.98 ± 34.11) ng/L,P ＜ 0.05) of CD8+ T lymphocytes cocultured with DMSCs compared with monocultured CD8+ T lymphocytes.Conclusions There is a strong expression of IL-13 by perilesional CD8+ T lymphocytes in patients with vitiligo,which may be inhibited by DMSCs and serve as a target for the treatment of vitiligo.