We consistently observed up‐regulation of infiltrating immune cells, expression of proinflammatory cytokines (IL‐1β, IL‐6, and TNF‐α), and osteoclastogenesis in the ligated periodontal tissues, and these observations were much rarer in the gingival tissues overexpressing PD‐L1 in basal KCs. This evidence concerns the gene TNF and dry eye syndrome.