CD209 and COVID-19: Taken together, the differential co-expression pattern of receptor–protease pairs in lung cells between healthy donors and COVID-19 patients suggested an enhanced SARS-CoV-2 tropism in AT2 and ciliated cells via ACE2 and macrophage/monocyte cells via CD209 and a reduced SARS-CoV-2 tropism in macrophages/monocytes and dendritic cells via NRP1 after SARS-CoV-2 infection.