In both rheumatoid arthritis and periodontitis, there is a pronounced irregularity in inflammatory cytokine pathways, and immunogenetic risk factors concerning IL-1, TNF, and Prostaglandin E2 expression are common, therefore therapeutic approaches targeting pathogenetic mechanisms of chronic inflammatory diseases like rheumatoid arthritis are valuable for periodontal research [6,23]. The gene discussed is TNF; the disease is periodontitis.