CCR1 and COVID-19: The association between COVID-19 phenotypes and CCR1 and CCR5 in particular also finds support from expression studies where elevated CCR1 expression in neutrophils and macrophages has been detected in patients with critical COVID-19 illness (Chua et al., 2020), in biopsied lung tissues from COVID-19 infected patients (Supplementary file 1h and Supplementary file 1i), as well as in Calu3 cells directly infected with COVID-19 (Supplementary file 1h and Supplementary file 1i).