This macrophage phenotype produces proinflammatory cytokines such as IL-1β, IL-6, IL-12, IL-18 and IL-23, TNF-α, and type I IFN; and several chemokines such as CXCL1, CXCL3, CXCL5, CXCL8, CXCL9, CXCL10, CXCL11, CXCL13, and CXCL16; CCL2, CCL3, CCL4, CCL5, CCL8, CCL15, CCL11, CCL19, and CCL20, most of which have been defined as part of the “first wave” of cytokines during the development of periodontal inflammation, acting as the first alarm signal for the assembly of a more complex and specific immune response and for the recruitment of professional immune cells to the site of infection [38]. The gene discussed is CCL15; the disease is infection.