This is in agreement with the findings of Roberts et al. [60], who found that the mononuclear cells derived from the periodontal tissue have the capacity to respond to the periodontal pathogens and their virulence factors and induce the expression of pro- and anti-inflammatory cytokines (IL-1α, IL-1β, IL-6, IL-8, IL-12, IL-13, TNF-α, and IFN-γ) in tissues affected by periodontal disease. The gene discussed is IFNG; the disease is periodontal disorder.