T-helper cells in the etiopathogenesis of periodontal disease: A mini review

Our traditional understanding of the T-helper (Th)1/Th2 paradigm in periodontal disease has undergone considerable changes in recent years. This review focuses on the Th subsets, including the recently identified cells of the CD4 lineage, their activation pathways and effector function in periodontal disease. The roles of Th17 and regulatory T (Treg) cells in disease pathogenesis have been explored. Newer Th subsets such as Th9 and Th22 cells and their potential role in periodontal disease have also been outlined.