CXCL8 and periodontitis: Periodontitis, due to its nature of infective inflammatory disease, involves the activation of the broad axis of innate immunity caused by the pathogenic action of subgingival microbiota through upregulation of proinflammatory cytokines from monocytes and polymorphonuclear leucocytes, including IL-1β, IL-6, IL-8, TNF-α and PGE2.