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)%, 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.