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

Abstract

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)%, X² = 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)%, X² = 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.