ACE2 and COVID-19: Consistently, SARS-CoV-2 infection triggered secretion of ACE2+TSG101+ EVs by human pneumocyte A549 cells overexpressing ACE2 (Supplementary Fig. 1e), implying that upregulated production of ACE2+ EVs is part of the innate response to SARS-CoV-2 infection in COVID-19 patients.