angiotensin converting enzyme 2 (ACE2), with the simultaneous involvement of human transmembrane protease, serine 2 (TMPRSS2), interacts with the S protein of SARS-CoV-2, which helps SARS-CoV-2 enter the host cell and induce PAD4-dependent NETosis, leading to fatal respiratory failure associated with an excessive inflammatory response (79). This evidence concerns the gene ACE2 and respiratory failure.