Changes of Th17 cells, Treg cells and Th17/Treg cell-associated cytokines in patients with tubercu-lous pleurisy and significance of the changes

Objective To investigate the significance of Th 17 cells, Treg cells and Th17/Treg cell-associated cytokines in the development of tuberculous pleurisy through detecting the expressions of Th 17 cells and Treg cells （CD4＋CD25＋Foxp3＋） in CD4＋T cells, analyzing concentrations of IL-17, IL-23, IL-6＆nbsp;and TGF-βin serum of patients with tuberculous pleurisy and healthy controls and measuring levels of IL -17, IL-23, IL-6 and TGF-βin hydrothorax of patients with tuberculous pleurisy .Methods Flow cytometry was used to detect expressions of Th 17 and Treg cells in peripheral blood of patients with tuberculous pleurisy and healthy controls.ELISA method was performed for quantitative detection of concentrations of IL -17, IL-23, IL-6 and TGF-βin serum and hydrothorax .Differences and correlations between the above measured data were analyzed by the statistical software SPSS 17.0.Results Compared with the healthy control group , the expressions of Th17 cells in peripheral blood of the patients were significantly increased （1.02%±0.20%vs.0.89%±0.13%, P=0.002〈0.05）, while the expressions of Treg cells were significantly decreased （4.64%±0.77%vs.5.10%±0.90%, P=0.000〈0.05）.Correspondingly, the ratio of Th17/Treg cells （0.25±0.07） in the patients were significantly higher than that in the healthy controls （0.17±0.05, P=0.000〈0.05）.Concentrations of IL-17, IL-23 and IL-6 in peripheral blood and in hydrothorax of the pa-tients were （17.49±3.94） ng/L, （90.42±23.06） ng/L, （4.54±1.02） ng/L and （26.13±5.98） ng/L, （122.26±31.71） ng/L, （5.31±0.74） ng/L respectively, which were remarkably higher than the levels of IL-17 （14.45±3.81） ng/L, IL-23 （77.55±20.26） ng/L and IL-6 （4.26±0.91） ng/L in control group. In tuberculous pleurisy group , concentrations of IL-17, IL-23 and IL-6 in hydrothorax were significantly higher than those in peripheral blood with P values of 0.000, 0.000 and 0.003.There was no difference be-tween IL-6 levels in peripheral blood from patients and IL-6 levels in peripheral blood from the healthy con-trols, P=0.274.In comparison with the control group , TGF-βlevels in peripheral blood and in hydrothorax of the patients were significantly decreased （3.95 ng/L±0.79 ng/L, 3.12 ng/L±0.77 ng/L vs.3.32 ng/L ±0.80 ng/L） .In tuberculous pleurisy patients , the expression of Th17 cells in peripheral blood was nega-tively correlated with Treg cells in peripheral blood （r=-0.684, P=0.000〈0.05）, but was positively relat-ed to the levels of IL-17, IL-23 and IL-6 （r=0.479, 0.441, 0.326, P=0.013, 0.015, 0.017）.TGF-βlevel had significantly positive correlations with Treg cells in the peripheral blood of the patients （r=0.297, P=0.024）, but no significant correlation with Th17 cells was found （r=0.091, P=0.659）.Conclusion Th17/Treg cell-associated cytokines might regulate the expressions of Th 17 and Treg cells and inflammatory reaction.Changes of Th17 cells, Treg cells and related cytokines might be important immunopathological mechanisms for tuberculous pleurisy . Key words: Th17 cell; Treg cell; Tuberculous pleurisy; Flow cytometry; Cytokine