IL17A and periodontitis: In periodontitis, the CD8+ T cells with an effector memory phenotype were shown to release anti-inflammatory cytokines (interleukin [IL]-10 and transforming growth factor [TGF]-β) and suppress bone-destructive cytokines (interferon [IFN]-γ and IL-17), and thus play a protective role for the alveolar bone (Cardoso and Arosa, 2017).