Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, China-Japan Friendship Hospital, Peking Union Medical College, Beijing, China.
Center for Interstitial and Rare Lung Diseases, Pneumology Department, Ruhrlandklinik, University Hospital, Essen, Germany.
Front Immunol. 2021 Nov 19;12:788502. doi: 10.3389/fimmu.2021.788502. eCollection 2021.
Sarcoidosis is a systemic inflammatory disorder of unknown etiology characterized by tissue infiltration with macrophages and lymphocytes and associated non-caseating granuloma formation. The disease primarily affects the lungs. Patients suffering from sarcoidosis show a wide range of clinical symptoms, natural history and disease outcomes. Originally described as a Th1-driven disease, sarcoidosis involves a complex interplay among diverse immune cells. This review highlights recent advances in the pathogenesis of sarcoidosis, with emphasis on the role of different immune cells. Accumulative evidence suggests Th17 cells, IFN-γ-producing Th17 cells or Th17.1 cells, and regulatory T (Treg) cells play a critical role. However, their specific actions, whether protective or pathogenic, remain to be clarified. Macrophages are also involved in granuloma formation, and M2 polarization may be predictive of fibrosis. Previously neglected cells including B cells, dendritic cells (DCs), natural killer (NK) cells and natural killer T (NKT) cells were studied more recently for their contribution to sarcoid granuloma formation. Despite these advances, the pathogenesis remains incompletely understood, indicating an urgent need for further research to reveal the distinct immunological events in this process, with hope to open up new therapeutic avenues and if possible, to develop preventive measures.
结节病是一种病因不明的全身性炎症性疾病，其特征为组织中巨噬细胞和淋巴细胞浸润，并伴有非干酪样肉芽肿形成。该疾病主要影响肺部。结节病患者表现出广泛的临床症状、自然病史和疾病结局。最初被描述为 Th1 驱动的疾病，结节病涉及多种免疫细胞之间的复杂相互作用。本综述重点介绍了结节病发病机制的最新进展，强调了不同免疫细胞的作用。越来越多的证据表明，Th17 细胞、IFN-γ 产生的 Th17 细胞或 Th17.1 细胞以及调节性 T（Treg）细胞发挥着关键作用。然而，它们的具体作用（保护或致病）仍有待阐明。巨噬细胞也参与肉芽肿形成，M2 极化可能与纤维化有关。以前被忽视的细胞，包括 B 细胞、树突状细胞（DC）、自然杀伤（NK）细胞和自然杀伤 T（NKT）细胞，最近也因其对结节病肉芽肿形成的贡献而受到研究。尽管取得了这些进展，但发病机制仍不完全清楚，这表明迫切需要进一步研究以揭示该过程中的独特免疫事件，以期开辟新的治疗途径，并在可能的情况下制定预防措施。
