IL17A and periodontitis: Furthermore, recent studies have found that Tregs (CD25/Foxp3 double-positive cells) may lose Foxp3 expression and convert to exFoxP3 Th17 cells in periodontitis, and decreased Tregs activity reduces the synthesis of TGF-β and IL-10, while these exFoxp3 Th17 cells express high levels of RANKL and IL-17; in contrast, when antibiotics were used to reduce the conversion of Treg cells, the Th17/Treg cell imbalance in periodontitis in mice was significantly inhibited and RANKL expression was suppressed, resulting in improved bone resorption (Deng et al., 2021).