Th122 - The Effects of Antimicrobial Peptide LL-37 on B Cells in Psoriatic Arthritis

Abstract Text: 【Background】Antimicrobial peptides released from neutrophils are involved in the pathogenesis of psoriatic arthritis (PsA). Among them, LL-37 is known to induce cytokine production from dendritic cells and T cells, triggering inflammation. However, its effects on B cells are unknown. This study aims to elucidate the effects of the antimicrobial peptide LL-37, which increases in the synovial fluid of psoriatic arthritis, on B cells.
【Methods】1) Using the public scRNA-seq database of synovium samples from patients with rheumatoid arthritis (RA) and PsA, gene expressions of B cell clusters were evaluated. 2) CD20+CD27+ memory B cells were collected by sorting from peripheral blood mononuclear cells, and cytokine production of TNF and IFNγ from B cells stimulated with LL-37 were examined by ELISA.
【Results】 1) A total of 202,203 cells were collected from synovium samples of 4 RA and 5 PsA patients. Among them, 4,249 cells were identified as B cells. Pathway analysis showed that inflammatory cytokine signaling pathways such as the IL-17 signaling pathway and the TNF signaling pathway were more detected in PsA. 2) When memory B cells were stimulated with BAFF and LL-37, TNF production was significantly enhanced compared to the control group. No difference was observed in IFNγ production.
【Conclusion】Antimicrobial peptides such as LL-37 might contribute to the production of inflammatory cytokines from B cells. We are now investigating what signaling pathways are activated using bulk RNA-seq.