Background:Age/Autoimmune-associated B cells (ABCs) are an emerging B cell subset that accumulate in aged and autoimmune-prone mice. Expansion of human ABCs has been observed in patients with autoimmune diseases like SLE and correlated with disease activity. However, it is less known whether ABCs contribute to the pathogenesis of RA.Objectives:The aim of this work was to explore the role of ABCs in RA.Methods:83 RA patients who met the 2010 ACR classification criteria for RA, 42 sex and age matched healthy control (HC), 35 Spondyloarthritis (SpA) and 31 Osteoarthritis (OA) patients were enrolled and blood samples were collected. The proportion of circulating ABCs was detected by flow cytometry and association with clinical and laboratory parameters were analyzed. Expression of characteristic proteins and inflammatory cytokines on ABCs were examined by quantitative real-time PCR.Results:The proportion of ABCs, defined as CD19+CD27-IgD-CD21-CD11c+, was significantly elevated in RA patients, compared with HC, SpA and OA patients. The frequency of ABCs was higher in patients with high disease activity (DAS28>3.2) compared with remission and low disease activity (DAS28<3.2). There was a positive correlation of ABCs with SJC, TJC, DAS28 whereas no association with RF and anti-CCP titer were observed. In addition, increased mRNA expression levels of T-bet, IL-21, MAF and IL-17 were noted on ABCs compared with CD19+CD27-CD11c- B cells.Conclusion:ABCs were expanded in RA patients and associated with active disease status. It might contribute to RA development by production of IL-17.References:[1]Cancro, M.P., Age-Associated B Cells. Annu Rev Immunol, 2020. 38(315-340).[2]F. Zhang, K. Wei, K. Slowikowski et al., Defining inflammatory cell states in rheumatoid arthritis joint synovial tissues by integrating single-cell transcriptomics and mass cytometry. Nat Immunol 2019, 20, 928-942.Disclosure of Interests:None declared
AB0060 INCREASED AGE/AUTOIMMUNE-ASSOCIATED B CELLS IN RA AND CLINICAL IMPLICATIONS