Among them, AhR activation by endogenous ligands inhibits NF-κB signaling and reduces local inflammation in multiple conditions, including periodontitis, bronchitis, and colitis; Additionally, 5-HIAA activates AHR in B cells to promote regulatory B (Breg) cell differentiation and inhibit arthritis inflammation (50–52). This evidence concerns the gene NFKB1 and bronchitis.