Dynamic immune responses are evident during the development of pulpitis. However, the cellular and molecular characterization of B cells in this context has long been neglected. This study investigates pulpitis through the lens of B-cell involvement, combining single-cell RNA sequencing with histopathological analysis to generate a comprehensive cellular atlas of healthy and inflamed dental pulp. Our findings reveal a near absence of B/plasma cells in healthy pulp but a marked increase during inflammation. These cells display active antigen presentation and immunoglobulin secretion. In the mouse pulpitis model, B-cell depletion alleviated pulpal inflammation, highlighting the proinflammatory role of B cells. Subclustering analysis identified 4 transcriptionally distinct B-cell subsets, which were validated at the protein level through multiplex immunofluorescence and flow cytometry. Among these, transitional B cells exhibited a noticeable breakdown of tolerance, suggesting a propensity for autoreactivity. Elevated autoantibodies were detected in both tissue samples and isolated plasma cells. Finally, Mendelian randomization analyses and serological assays in mice indicated potential local–systemic interactions in pulpitis. These findings reveal that B cells may contribute to both the local pathology and systemic immunological characteristics of pulpitis, providing a novel perspective on its pathogenesis through potential autoimmune mechanisms.
Chen et al. (Wed,) studied this question.