In the setting of periodontitis, a multitude of signals, such as pro- and anti-inflammatory cytokines upregulated in the macrophages themselves, as well as M1-stimulating (IFN-γ) and M2-stimulating (IL-4) cytokines upregulated in T-helper cells, may combine to generate a macrophage phenotype. The gene discussed is IFNG; the disease is periodontitis.