In vitro effects of tea polyphenols on the secretion of TNF-α, IFN-γ and IL-2R by peripheral blood CD8＋ T lymphocytes from vitiligo patients

Abstract

Objective To detect the level of cytokines and their receptors secreted by peripheral blood CD8＋ T lymphocytes from vitiligo patients, and to evaluate the influence of tea polyphenols on their secretion. Methods CD8＋ T lymphocytes were isolated from the peripheral blood of 12 patients with progressive vitiligo, 12 patients with stable vitiligo and 10 healthy controls, and cultured in vitro for 20 days. Then, some CD8＋ T lymphocytes were treated with tea polyphenols of 100 mg/L for two days. Enzyme-linked immunosorbent assay （ELISA） was carried out to determine the levels of tumor necrosis factor （TNF）-a, interferon （IFN）-a and interleukin-2 receptor （IL-2R） in the culture supernatants of CD8＋ T lymphoeytes before and after the treatment with tea polyphenols. Analysis of variance and t test were conducted to assess differences in these parameters among these groups and changes between pretreatment and posttreatment, respectively. Results There was a sequential decrease in the level of TNF-a （（ 191.302±6.077） vs. （175.966± 2.467） vs. （173.664 ± 3.600） ng/L, F = 4.784, P 〈 0.05）, bat a sequential increase in that of IFN-a （ （280.182 ± 36.070） vs. （371.670 ± 24.352） vs. （447.147 ± 8.432） ng/L, F= 9.036, P〈 0.01） and IL-2R （（8.375 ± 0.161） vs. （8.845 ±0.161） vs. （9.345 ± 0.125） ng/L, F = 9.639, P 〈 0.01） in the culture supernatant of CD8＋ T lymphocytes from patients with progressive vitiligo to patients with stable vitiligo and healthy controls. After two days of tea polyphenol treatment, a statistical decrease was observed in the level of TNF-a in the culture supematant of CD8 ＋ T lymphocytes from patients with progressive vitiligo （（ 164.797 ± 1.784） ng/L, P 〈 0.01 ）, patients with stable vitiligo （（166.150 ± 3.576） rig/L, P 〈 0.05） and healthy controls （（155.028 ± 5.759） ng/L, P 〈 0.05）, but no statistical changes were noted for IFN-＇y or IL-2R （all P 〉 0.05） despite a slight elevation in the level of IFN-＇y in the culture supernatant of CD8＋ T lymphocytes from patients with stable vitiligo and in that of IL-2R from all the three groups as well as a mild reduction in that of IFN-Y from patients with progressive vitiligo and healthycontrols. Conclusions The changes of cytokines and their receptors secreted by CD8＋ T lymphocytes may be associated with the induction and progression of vitiligo. Tea polyphenols may treat vitiligo via suppressing the secretion of TNF-a by CD8＋ T lymphocytes. Key words: Vitiligo, CDS-positive T-lymphocytes; Tumor necrosis factor alpha; Interferon type II; Recep-tors, interleukin-2; Tea polyphenols