We decided to include markers of cell types involved in the pathogenesis of COVID‐19, such as platelets (CD31 and CD42b), endothelial cells (CD34 and CD31), leukocytes (CD45), pericytes (CD140b), NK cells (CD56), neural cells (CD56 and N‐cadherin) and cardiomyocytes (N‐cadherin). The gene discussed is PECAM1; the disease is COVID-19.