Th1 cells have been well documented as the major protective factors in the resolution of chlamydial infection mainly through producing IFN‐γ 6; Th17 cells express retinoid‐acid receptor‐related orphan receptor gamma t (RORγt) and producing multiple pro‐inflammatory cytokines such as interleukin 17 (IL‐17) and IL‐22 14. The gene discussed is IL17A; the disease is chlamydia trachomatis infectious disease.