In different models, (s)ACE2, Ag (1–7) or Ag (1–9) upregulation has been associated to pathological conditions such as inflammation of the kidneys and gastrointestinal tract, cardiac dysfunction, human cirrhosis, lung injury/fibrosis and microvascular thrombosis [59,60,61,62,68,107,108,122,123,124,125]; also, Ag (1–7) antiproliferative and apoptotic effects, possibly in part through IL-10 upregulation [110], may mediate eosinopenia and lymphopenia (two features commonly seen in COVID-19 patients), potentially impairing immune system ability to counteract viral infection [126,127,128,129]. This evidence concerns the gene ACE2 and viral infectious disease.