Our current study identified that in the liver, PADI2 and PADI4 were elevated in SARS-CoV-2 biopsies, compared with control lung biopsies, and the roles of PAD2 have previously been identified in liver fibrosis [130], while PAD4-mediated NETosis has been linked to liver vasculature and liver injury in bacterial infection [131]. Here, PADI2 is linked to bacterial infectious disease.