Because SARS-CoV-2 and its S-proteins are present in tissues and bodily fluids of infected patients and COVID-19 pathology includes endotheliopathy and leukocyte infiltration into the lungs [7,17,18], it is important to determine whether viral S-proteins directly contribute to these lung pathologies and whether leukocyte interactions with the vascular endothelium influence SARS-CoV-2-induced pathologies. This evidence concerns the gene PROS1 and COVID-19.