ACE2 and COVID-19: Thrombi showed few ACE2 positive (ACE2+) cells, although a higher ACE2+ area in thrombi of COVID-19 patients was apparent compared to controls (respectively, median ACE2+ area as % over total thrombus area = 0.05%, [IQR 0.02–0.06] vs. 0.01%, [IQR 0.01–0.03], p = 0.04) (Fig. 1A).