DPP4 and severe acute respiratory syndrome: Three of the seven human coronaviruses including the severe acute respiratory syndrome (SARS)-related beta-coronaviruses (sarbecoviruses) SARS-CoV-1 and SARS-CoV-2, as well as the common cold coronavirus HCoV-NL63, use angiotensin-converting enzyme 2 (ACE2) as a receptor, whereas Middle East respiratory syndrome coronavirus (MERS-CoV) uses dipeptidyl peptidase-4 (DPP4)11–14.