The results showed that 10 ICD-related genes were up-regulated, including ATG5, CASP1, CASP8, EIF2AK3, ENTPD1, ENTPD1, HSP90AA1, MYD88, PIK3CA and TLR4, while 4 genes (BAX, CD4, FOXP3 and TNF) were down-regulated in the COVID-19 samples (Fig. 1A,B). Here, TLR4 is linked to COVID-19.