The Gram-negative oral anaerobe P. gingivalis, implicated in the pathogenesis of periodontitis, contributes to the induction of elevated levels of inflammatory cytokines, including interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α.6 These inflammatory cytokines are important for host resistance to bacterial invasion and are one of the steps in inflammatory regulation. This evidence concerns the gene IL6 and periodontitis.