Classical AAbs targeting Angiotensin II (AngII), Angiotensin Converting Enzyme 2 (ACE2) and MAS1 oncogene (MAS) receptors were frequently observed in COVID-19 patients, suggesting that the production of GPCR-fAAb may begin even at the time of acute COVID-19 infection [56,57,58]. Here, AGT is linked to COVID-19.