TABLE 3.

Essential identified genes for each cell type.

Cell type	Gene symbol	Description
B cell	IFI44L	IFI44L negatively regulates the innate immune response induced by viral infection.
	FOS	FOS can be used as a key target for puerarin in the treatment of COVID-19.
CD4+ T cell	ZFP36L2	ZFP36 can downregulate the expression of pro-inflammatory cytokines such as IL-17 and IFN-γ, thereby regulating T cell activation and antiviral immunity.
CD8+ T cell	MT2A	MT2A may be a response to SARS-CoV-2 virus infection through changes in metal homeostasis in T cells.
Natural killer cell	NCR2	The selective expression of splice variants of NCR2 is significantly associated with infection.
	LY6E	LY6E plays an important role in immune regulation and participates in the viral infection process of coronavirus.
Dendritic cell	STAT1	STAT1 plays a role in transcriptional activation in the nucleus in homologous or heterodimeric forms.
Monocyte	S100A8	S100A8/A9 and neutrophil abnormalities are related to the occurrence of COVID-19, and may serve as a new target for COVID-19 therapeutic intervention.