Abstract: Periodontitis is a common oral disease in human. The immune mechanism plays an important role in the development of periodontitis. In recent years, it has been found that programmed death 1 (PD-1) and its ligands are important molecules involved in immunosuppression. It has been demonstrated that the molecules involved in PD-1 signaling can be expressed on peripheral blood lymphocytes, periodontal ligament fibroblasts and gingival epithelial cells in patients with periodontitis. This article is to discuss the correlation between PD1 signaling pathway and periodontitis.

Key words: programmed death 1 (PD-1), periodontitis, immune mechanism