IL-33 is a cellular sensor that mediates the pathogenesis of allergic and autoimmune diseases such as rheumatoid arthritis, psoriasis, inflammatory bowel diseases, etc. This cytokine stimulates TNF by activating MCs and is overexpressed in gingival tissues, with periodontitis and bone loss mediated by the increase of the nuclear factor receptor kappa-β ligand (RANKL) [64]. The gene discussed is TNF; the disease is rheumatoid arthritis.