AHR and allergic disease: AhR can regulate the Th1/Th2 balance by activating Th0 cells, and a synthetic anti-allergy agent M50367 (as AhR ligand) exerts anti-allergic effects by suppressing the differentiation of Th0 cells into Th2 cells in vitro, tilting the Th1/Th2 balance in favor of Th1 (71).