CD14 and COVID-19: Proportion of CD14+ monocyte increased significantly in severe COVID-19 compared to that in the mild COVID-19 and control group, whereas those of CD16+ non-classical monocyte (vs controls), CD14+CD16+ monocytes (vs mild COVID-19), and DC2 significantly (vs mild COVID-19 and controls) decreased in severe COVID-19 (Fig. 2b, c).