SARS-CoV-2 is the novel coronavirus responsible for the current COVID-19 pandemic. Severe complications are observed only in a small proportion of infected patients but the cellular mechanisms underlying this progression are still unknown. Comprehensive flow cytometry of whole blood samples from 54 COVID-19 patients reveals a dramatic increase in the number of immature neutrophils. This increase strongly correlates with disease severity and is associated with elevated IL-6 and IP-10 levels, two key players in the cytokine storm. The most pronounced decrease in cell counts is observed for CD8 T-cells and VD2 γδ T-cells, which both exhibit increased differentiation and activation. ROC analysis reveals that the count ratio of immature neutrophils to VD2 (or CD8) T-cells predicts pneumonia onset (0.9071) as well as hypoxia onset (0.8908) with high sensitivity and specificity. It would thus be a useful prognostic marker for preventive patient management and improved healthcare resource management.

SARS-CoV-2 是导致当前 COVID-19 大流行的新型冠状病毒。仅在一小部分感染患者中观察到严重并发症，但这种进展背后的细胞机制仍不清楚。对 54 名 COVID-19 患者的全血样本进行综合流式细胞术显示，未成熟中性粒细胞的数量急剧增加。这种增加与疾病严重程度密切相关，并与细胞因子风暴中的两个关键因素 IL-6 和 IP-10 水平升高相关。细胞计数减少最明显的是 CD8 T 细胞和 VD2 γδ T 细胞，它们都表现出分化和激活增加。ROC 分析显示，未成熟中性粒细胞与 VD2（或 CD8）T 细胞的计数比可预测肺炎发作 (0.9071) 以及缺氧发作 (0.8908)，具有高敏感性和特异性。因此，它将成为预防性患者管理和改进医疗资源管理的有用预后标志。