目的:CD21-/低记忆B细胞(MBC)的子集,包括双负(DN,CD27-IgD-)和Tbet+CD11c+细胞,在慢性炎症性疾病中扩展。在类风湿性关节炎(RA)中,CD21-/低MBC与关节破坏相关。然而,这是否是由于Tbet+CD11c+子集,其功能和对RA的致病贡献尚不清楚。这项研究旨在研究CD21-/低TbetCD11cMBCs与关节破坏以及其他临床参数之间的关联,并阐明其在未经治疗的RA患者(uRA)中的功能特性。
方法:临床观察结合流式细胞术(n=36)和uRA患者外周血MBCs的单细胞(sc)RNA和V(D)J测序(n=4)。将循环Tbet+CD11c+MBC的转录组与滑膜B细胞的scRNA测序数据进行比较。使用Tbet+CD11c+B细胞与T细胞的体外共培养来评估共刺激能力。
结果:外周血中CD21-/低Tbet+CD11c+MBCs与骨破坏相关,但未分析其他临床参数。Tbet+CD11c+MBC经历了克隆扩增并表达体细胞突变的V基因。这些细胞的基因表达分析确定了与抗原呈递功能相关的150多个上调基因的独特特征,包括:BCR激活和网格蛋白介导的抗原内化,调节肌动蛋白丝,内体和溶酶体,抗原加工,加载,演示和共同激励,一个转录组反映在它们的滑膜组织对应物中。体外,Tbet+CD11c+B细胞诱导CD4+T细胞RORγT表达,从而极化Th17细胞,对破骨细胞生成至关重要并与骨破坏相关的T细胞亚群。
结论:本研究提示Tbet+CD11c+MBCs通过抗原呈递促进骨破坏而参与RA的发病。T细胞活化和Th17极化。
OBJECTIVE: Subsets of CD21-/low memory B cells (MBCs), including double-negative (DN, CD27-IgD-) and Tbet+CD11c+ cells, are expanded in chronic inflammatory diseases. In rheumatoid arthritis (RA), CD21-/low MBCs correlate with joint destruction. However, whether this is due to the Tbet+CD11c+ subset, its function and pathogenic contribution to RA are unknown. This study aims to investigate the association between CD21-/lowTbet+CD11c+ MBCs and joint destruction as well as other clinical parameters and to elucidate their functional properties in patients with untreated RA (uRA).
METHODS: Clinical observations were combined with flow cytometry (n = 36) and single-cell RNA sequencing (scRNA-seq) and V(D)J sequencing (n = 4) of peripheral blood (PB) MBCs from patients with uRA. The transcriptome of circulating Tbet+CD11c+ MBCs was compared with scRNA-seq data of synovial B cells. In vitro coculture of Tbet+CD11c+ B cells with T cells was used to assess costimulatory capacity.
RESULTS: CD21-/lowTbet+CD11c+ MBCs in PB correlated with bone destruction but no other clinical parameters analyzed. The Tbet+CD11c+ MBCs have undergone clonal expansion and express somatically mutated V genes. Gene expression analysis of these cells identified a unique signature of more than 150 up-regulated genes associated with antigen presentation functions, including B cell receptor activation and clathrin-mediated antigen internalization; regulation of actin filaments, endosomes, and lysosomes; antigen processing, loading, presentation, and costimulation; a transcriptome mirrored in their synovial tissue counterparts. In vitro, Tbet+CD11c+ B cells induced retinoic acid receptor-related orphan nuclear receptor γT expression in CD4+ T cells, thereby polarizing to Th17 cells, a T cell subset critical for osteoclastogenesis and associated with bone destruction.
CONCLUSIONS: This study suggests that Tbet+CD11c+ MBCs contribute to the pathogenesis of RA by promoting bone destruction through antigen presentation, T cell activation, and Th17 polarization.