The role of Lyn in immunity and chronic inflammation: Implications for periodontitis

Lyn kinase, a critical immune regulator, is well-established in systemic autoimmune diseases, but its role in periodontitis remains unclear. This narrative review synthesizes literature up to July 2025 from PubMed, Scopus, and Web of Science to examine the immunoregulatory functions of Lyn and discuss its potential role in periodontitis. Current evidence indicates that Lyn may be relevant to multiple processes implicated in periodontal pathogenesis, including B-cell signaling, Th17-related inflammatory networks, neutrophil-associated responses, NF-κB- and IL-1β-related inflammation, and inflammatory bone resorption. However, direct periodontal evidence remains limited and is derived largely from transcriptomic, bioinformatic, and cross-disease studies, together with mechanistic extrapolation from other inflammatory settings. Accordingly, Lyn should currently be regarded not as an established mechanistic driver, but as a hypothesis-generating molecular candidate in periodontitis. This review proposes a periodontitis-centered conceptual framework for future periodontal-specific investigation of Lyn.