MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, United Kingdom.
National Institute for Health Research Surgical Reconstruction and Microbiology Research Centre, Queen Elizabeth Hospital Birmingham, Birmingham, United Kingdom.
Front Immunol. 2021 Jun 2;12:680134. doi: 10.3389/fimmu.2021.680134. eCollection 2021.
Whilst the majority of individuals infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative pathogen of COVID-19, experience mild to moderate symptoms, approximately 20% develop severe respiratory complications that may progress to acute respiratory distress syndrome, pulmonary failure and death. To date, single cell and high-throughput systems based analyses of the peripheral and pulmonary immune responses to SARS-CoV-2 suggest that a hyperactive and dysregulated immune response underpins the development of severe disease, with a prominent role assigned to neutrophils. Characterised in part by robust generation of neutrophil extracellular traps (NETs), the presence of immature, immunosuppressive and activated neutrophil subsets in the circulation, and neutrophilic infiltrates in the lung, a granulocytic signature is emerging as a defining feature of severe COVID-19. Furthermore, an assessment of the number, maturity status and/or function of circulating neutrophils at the time of hospital admission has shown promise as a prognostic tool for the early identification of patients at risk of clinical deterioration. Here, by summarising the results of studies that have examined the peripheral and pulmonary immune response to SARS-CoV-2, we provide a comprehensive overview of the changes that occur in the composition, phenotype and function of the neutrophil pool in COVID-19 patients of differing disease severities and discuss potential mediators of SARS-CoV-2-induced neutrophil dysfunction. With few specific treatments currently approved for COVID-19, we conclude the review by discussing whether neutrophils represent a potential therapeutic target for the treatment of patients with severe COVID-19.
虽然大多数感染严重急性呼吸综合征冠状病毒 2(SARS-CoV-2)的个体,即 COVID-19 的病原体,仅出现轻度至中度症状,但约 20%的患者会发展为严重的呼吸道并发症,可能进展为急性呼吸窘迫综合征、肺衰竭和死亡。迄今为止,基于单细胞和高通量系统对 SARS-CoV-2 外周和肺部免疫反应的分析表明,过度活跃和失调的免疫反应是导致严重疾病的基础,其中中性粒细胞起着重要作用。其特征部分表现为中性粒细胞胞外诱捕网(NETs)的大量生成,循环中不成熟、免疫抑制和活化的中性粒细胞亚群的存在,以及肺部中性粒细胞浸润,粒细胞特征正在成为严重 COVID-19 的一个决定性特征。此外,评估入院时循环中性粒细胞的数量、成熟状态和/或功能,已作为识别有临床恶化风险的患者的预后工具显示出一定的前景。在这里,通过总结研究 SARS-CoV-2 外周和肺部免疫反应的结果,我们全面概述了 COVID-19 患者中性粒细胞库在不同疾病严重程度下的组成、表型和功能变化,并讨论了 SARS-CoV-2 诱导中性粒细胞功能障碍的潜在介质。由于目前针对 COVID-19 批准的具体治疗方法很少,我们通过讨论中性粒细胞是否代表治疗严重 COVID-19 患者的潜在治疗靶点来结束综述。