Unbalanced expression of aryl hydrocarbon receptor in peripheral blood CCR6+ CD4+ and CD4+ CD25+ T cells of rheumatoid arthritis

Objective: The goal of this study was to analyze the role of aryl hydrocarbon receptor in peripheral blood CCR6(+) CD4(+) and CD4(+) CD25(+)T cells of patients with rheumatoid arthritis. Methods: Flow cytometry was applied to determine the proportion of AhR positive cells in CCR6(+) CD4(+)T, CD4(+) CD25(+)T and peripheral blood peripheral mononuclear cells from each subject. AhR mRNA and CYP1A1 mRNA relative expression levels were tested by real-time PCR. Results: The percentage of AhR positive cells in peripheral blood mononuclear cells was higher in RA group than that in healthy cases [(35.23 +/- 10.71)% vs. (18.83 +/- 7.32)%, p < 0.01]. The expression levels of AhR and CYP1A1 were both increased in patients with RA while compared to controls [(3.71 +/- 1.63) vs. (2.00 +/- 1.27), p = 0.002; (2.62 +/- 2.08) vs. (0.62 +/- 0.29), p < 0.01, respectively]. In RA patients, the percentage of AhR positive cells in CD4(+) CD25(+)T cells was significantly lower than that from controls [17.90 (6.10 +/- 80.10)% vs. (52.49 +/- 19.18)%, p < 0.01]; In healthy controls, the percentage of AhR positive cells in CD4(+) CD25(+)T cells was significantly higher than that in CCR6(+) CD4(+)T cells, and was also significantly higher than that in PBMCs [(52.49 +/- 19.18)% vs. (23.18 +/- 5.62)% vs. (18.06 +/- 7.80)%, X-2 = 24.03, p < 0.01]; in RA patients, the percentage of AhR positive cells in CCR6(+) CD4(+)T cells was significantly increased than that in CD4(+) CD25(+)T cells and PBMCs [(46.02 +/- 14.68)% vs. 17.90 (6.10 +/- 80.10)% vs. (34.22 +/- 10.33)%, X-2 = 38.29, p < 0.01]; Nevertheless, no statistically significant relationship was found between clinical data and AhR positive cells in CCR6(+) CD4(+)T and CD4(+) CD25(+)T cells. Conclusion: AhR may participate in the pathological progress of RA by controlling the differentiation of Th17 and Treg cells in peripheral blood. (C) 2016 Elsevier Editora Ltda.