Blood myeloid cells are known to be dysregulated in coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2. It is unknown whether the innate myeloid response differs with disease severity and whether markers of innate immunity discriminate high-risk patients. Thus, we performed high-dimensional flow cytometry and single-cell RNA sequencing of COVID-19 patient peripheral blood cells and detected disappearance of non-classical CD14^LowCD16^High monocytes, accumulation of HLA-DR^Low classical monocytes (Human Leukocyte Antigen - DR isotype), and release of massive amounts of calprotectin (S100A8/S100A9) in severe cases. Immature CD10^LowCD101⁻CXCR4^+/− neutrophils with an immunosuppressive profile accumulated in the blood and lungs, suggesting emergency myelopoiesis. Finally, we show that calprotectin plasma level and a routine flow cytometry assay detecting decreased frequencies of non-classical monocytes could discriminate patients who develop a severe form of COVID-19, suggesting a predictive value that deserves prospective evaluation.

已知在由SARS-CoV-2引起的2019年冠状病毒病（COVID-19）中，血液髓样细胞失调。尚不清楚先天性骨髓反应是否随疾病的严重程度而有所不同，先天性免疫的标志物是否能区分高危患者。因此，我们对COVID-19患者外周血细胞进行了高维流式细胞术和单细胞RNA测序，并检测到非经典CD14^低CD16^高单核细胞的消失，HLA-DR^低经典单核细胞的积累（人类白细胞抗原-DR同种型），并在严重情况下释放大量钙卫蛋白（S100A8 / S100A9）。未成熟的CD10^低CD101 ⁻ CXCR4 ^+/-具有免疫抑制特征的中性粒细胞在血液和肺中积累，提示紧急骨髓形成。最后，我们表明钙卫蛋白血浆水平和检测非经典单核细胞频率降低的常规流式细胞术检测可以区分发展出严重形式的COVID-19的患者，提示其预测价值值得进行前瞻性评估。