To characterize the host immune and inflammatory responses in COVID-19 patients, genome-wide RNA-sequencing analysis was performed, which indicated that the proportion of immune cells in the blood was reduced in patients who required non-ICU admission, with lower levels of G-CSF, CXCL10/IP-10, CCL2/MCP-1 and CCL3/MIP-1A detected. This evidence concerns the gene CCL2 and COVID-19.