Synovial tissue macrophages (STMs) were principally recognized as having a pro-inflammatory role in rheumatoid arthritis (RA), serving as the main producers of pathogenic tumour necrosis factor (TNF). Recent advances in single-cell omics have facilitated the discovery of distinct STM populations, providing an atlas of discrete phenotypic clusters in the context of healthy and inflamed joints. Interrogation of the functions of distinct STM populations, via ex vivo and experimental mouse models, has re-defined our understanding of STM biology, opening up new opportunities to better understand the pathology of the arthritic joint. These works have identified STM subpopulations that form a protective lining barrier within the synovial membrane and actively participate in the remission of RA. We discuss how distinct functions of STM clusters shape the synovial tissue environment in health, during inflammation and in disease remission, as well as how an increased understanding of STM heterogeneity might aid the prediction of clinical outcomes and inform novel treatments for RA.

滑膜组织巨噬细胞（STM）主要被认为在类风湿性关节炎（RA）中具有促炎作用，是致病性肿瘤坏死因子（TNF）的主要产生者。单细胞组学的最新进展促进了不同 STM 群体的发现，提供了健康和发炎关节背景下离散表型簇的图谱。通过离体和实验小鼠模型对不同 STM 群体的功能进行询问，重新定义了我们对 STM 生物学的理解，为更好地了解关节炎关节的病理学开辟了新的机会。这些工作已经确定了 STM 亚群，它们在滑膜内形成保护性衬里屏障，并积极参与 RA 的缓解。我们讨论了 STM 簇的不同功能如何在健康、炎症和疾病缓解期间塑造滑膜组织环境，以及对 STM 异质性的深入了解如何有助于预测临床结果并为 RA 的新治疗提供信息。