Additionally, PCR analyses further implied that the increased mRNA expression levels of cytokines (IL-22, IL-17A, TNF-α, IL-6 and IL-23) and transcription factors (AHR and RORγt) possibly contributed to expanding the number of cTh22 and cTh17 cells in patients with EV71-associated HFMD, particularly in the severe patients. The gene discussed is AHR; the disease is hand, foot and mouth disease.