ACE2 and infection: It has been reported that angiotensin-converting enzyme 2 (ACE2) is the main host cell receptor of human pathogenic coronaviruses [severe acute respiratory syndrome coronavirus (SARS-CoV), HCoV-NL63, and SARSCoV-2 (COVID-19)], and it plays a crucial role in the entry of virus into the cell to cause the final infection (1).