UMAP and FlowSOM clustering analysis of live, CD3-/CD14-/CD19-/CD56- cells (cleaned from lymphocyte and monocyte lineages) revealed mild and severe COVID-19 patients to harbor clearly distinct population distribution than HC (Fig 1A, UMAP of live PBMCs without lymphocyte and monocyte lineage removal depicted in S1 Fig). This evidence concerns the gene NCAM1 and COVID-19.