The severity of HIV and dengue virus infections is also related to the level of endotoxin (LPS) in the human body. Lipopolysaccharide activates CD14 + Monocytes. Monocytes are innate immune cells that participate in the complex inflammatory response after migrating to tissues and lymphoid organs, including phagocytosis, antigen presentation, and cytokine secretion . Structural insight reveals that SARS-CoV-2 ORF7a is an immunomodulatory factor of human CD14 + monocytes . The SARS-CoV-2 ORF7a extracellular domain (residues 14-96) binds to CD14 + monocytes derived from human peripheral blood mononuclear cell(PBMC) with the highest efficiency, but the binding molecule could not be determined. The combination of ORF7a and CD14 monocytes inhibits the antigen presentation ability of these monocytes. SARS-CoV-2 ORF7a triggers CD14 + monocyte antigen presentation inhibition. Orf7a has the ZF domain 'CELYHYQEC'. The ORF7a with the Cys-rich accessory protein may be associated with zinc-binding and interaction of cell antigens (can be activated by a wide range of disulfide) 50 . SARS-CoV-2 ORF7a is an immunomodulatory factor combined with immune cells and triggers a severe inflammatory response. SARS-CoV-2 ORF7a is incubated with CD14 + monocytes. In vitro, it starts the reduction of HLA-DR/DP/DQ expression level and promotes cytokines, including IL-6, IL-1β, IL-8 and TNF-α . Among hospitalized patients diagnosed with COVID-19, especially in intensive care unit patients, the percentage of peripheral blood CD14 + CD16 + inflammatory monocytes is higher . In mild and severe COVID-19 patients, the IL-6 production of inflammation CD14 + CD16 + monocytes increased significantly, indicating that monocytes are a key factor in the cytokine storm .