ACE2 and COVID-19: It has been observed that ACE2 autoantibody levels are increased in individuals with severe COVID-19 compared to those with mild infection, suggesting a pathogenic role [49,50,68,69,70] and a positive correlation between the levels of antibodies to spike protein (S1-RBD) and autoantibodies to ACE2 has been reported in COVID-19 patients [71].