Association between the ratio of aryl hydrocarbon receptor (AhR) in Th17 cells to AhR in Treg cells and SLE skin lesions.

Skin lesions are typical clinical manifestations of systemic lupus erythematosus (SLE) and the biomarker for predicting SLE skin injury is not clear. We conducted a hospital-based case-control study with aim to explore the predictive value of the ratio of aryl hydrocarbon receptor (AhR) in T helper 17 (Th17) cells to AhR in regulatory T (Treg) cells (AhR ratio) in SLE skin lesions. The clinical and laboratory data were obtained from their medical records, and the AhR relative expression levels were evaluated by reverse transcription-quantitative polymerase chain reaction. Flow cytometry was applied to determine the proportion of AhR-overexpressing cells in Th17 and Treg cells. Pearson's correlation and logistic regression analyses were used to evaluate the association between AhR ratio risk of skin lesions. Results showed that the expression level of AhR in peripheral blood mononuclear cells was increased >3-fold in patients with SLE compared with that in healthy controls. Compared with control group, the percentage of AhR-overexpressing cells to Th17 cells was statistically higher in patients with SLE, whereas no significant difference was observed in the percentage of AhR-overexpressing cells to Treg cells between patients with SLE and control group. AhR ratio was also higher in SLE, and it was negatively correlated with complement 3 while positively correlated with erythrocyte sedimentation rate. In addition, compared with the low-AhR ratio group, more younger SLE patients with skin lesions, ultraviolet allergies and lower C3 levels were observed in the high-AhR ratio group, implicating that AhR ratio may be a potential biomarker for predicting SLE skin injury.