Regarding the downregulated geneset, MHC II molecules, including HLA-DQA1, HLD-DRA, HLA-DRB1, HLA-DMB, HLA-DMA, etc., and cytokine/chemokine genes, including IL1B, TNF, CCL3, CCL4, and CXCL8 were expressed at lower levels in COVID-19 patients, especially those with severe diseases (Fig. 2e). This evidence concerns the gene CCL3 and COVID-19.