Aryl hydrocarbon receptor involved in Th17/Treg imbalance in chronic hepatitis B via the AhR–RORγt–FoxP3 axis

Abstract Objectives: To investigate the involvement of aryl hydrocarbon receptor (AhR) in the Th17/Treg imbalance of chronic hepatitis B (CHB) via the AhR–RORγt–FoxP3 axis. Methods: The proportions of Th17 and Treg cells in peripheral venous blood collected from 18 healthy controls (HCs) and 30 patients with CHB were determined by flow cytometry. AhR, retinoic acid-related orphan receptor gamma t (RORγt), and forkhead box protein 3 (FoxP3) mRNA levels were tested by RT-qPCR. Moreover, AhR, RORγt and FoxP3 protein levels were detected by western blot. Results: The proportions of Th17 and Treg cells were significantly higher in the CHB group than those in the HC group ( p < 0.005). The Th17/Treg ratio was remarkably higher in the CHB group than that in the HC group ( p < 0.001). Furthermore, AhR , RORγt , and FoxP3 mRNA levels were higher in the CHB group than those in the HC group ( p ≤ 0.001). The expression levels of AhR, RORγt and FoxP3 protein were higher in the CHB group than those in the HC group. Moreover, there were positive correlations between AhR and RORγt mRNA ( p < 0.001, r = 0.632) and between AhR and FoxP3 mRNA ( p < 0.001, r = 0.798). Conclusion: The AhR–RORγt–FoxP3 axis may mediate Th17/Treg balance in CHB to influence disease development.