Among them, the expression levels of ENTPD1, HMGB1, HSP90AA1, ATG5, CASP8, EIF2AK3, PIK3CA, CASP1, MYD88, and TLR4 were up-regulated, whereas BAX, TNF, CD4, and FOXP3 were down-regulated in COVID-19 samples than that in non-COVID-19 controls (Figure 1A). Here, TLR4 is linked to COVID-19.