It is also found that downregulation of CYP1A2 is observed during inflammation [56], whereas AhR activation protects intestinal epithelium from enterocolitis by promoting CYP1A2 expression [57–59], and that indole derivatives activate AhR to promote IL-22 secretion, which boosts intestinal mucosal defense [60]. The gene discussed is AHR; the disease is enterocolitis.