B-lineage cells interact with antimicrobial peptides in the gingival tissue of stage 4 periodontitis.

<title>Abstract</title> <p>Periodontitis is a major public health problem worldwide as it causes teeth loss and worsens systemic diseases such as diabetes and rheumatoid arthritis. Severe forms corresponding to stage 3 and stage 4 periodontitis are characterized by severe alveolar bone destruction and immune dysregulation, with B-lineage cells and antimicrobial peptides (AMPs) playing pivotal roles. However, the spatial and functional interactions of these actors in gingival tissues remain poorly understood. In this study, B-lineage cells in stage 4 periodontitis were identified and their association with AMPs deciphered. Gingival tissues from 10 patients and 2 healthy controls were analyzed using imaging mass cytometry (IMC), confocal microscopy immunofluorescence, and spatial proximity assays. Immune cell densities, phenotypic profiles, and the presence of AMPs (HNP1-3, LL-37) were quantified. B-lineage cells, particularly antibody-secreting cells, were significantly enriched in stage 4 periodontitis tissues and colocalized with HNP1-3 + neutrophils. Intracellular HNP1-3 was detected in plasma cells, suggesting possible internalization and an influence on plasma cell activity. These findings highlight a novel interaction between B-lineage cells and AMPs, providing insights into the immunopathogenesis of periodontitis and potential therapeutic targets.</p>