Notably, in severe/critical COVID-19 patients in the recovery stage, the proportion of CD14 monocytes (based on the expression of the marker genes CST3, LYZ, CD14) in PBMCs were elevated, but CD4 T cells (IL7R, LTB) were decreased (Figure 1C), consistent with a previous report (9). This evidence concerns the gene CST3 and COVID-19.