IL17A and periodontitis: Since Th1 and Th17 cells play crucial roles in the pathogenesis of EAE, the percentages of Th1 (IFN-γ+CD4+) and Th17 (IL-17+CD4+) cells in the peripheral blood were analyzed by flow cytometry to elucidate the potential mechanism by which periodontitis affects the peripheral immune CD4+ T cell subsets.