TNF and periodontitis: F. alocis lipoteichoic acid has recently been shown to induce the expression of proinflammatory cytokines (TNF-α, IL-6, IL-8, and MMP-2) in human gingival fibroblasts, similar to the lipopolysaccharide of historically associated Gram-negative bacteria with periodontitis, confirming the pathogenic potential in the development and progression of periodontitis associated with this bacterium [35] According to Cross et al., D. oralis has been isolated in coaggregation with F. nucleatum [8].