CD4 and COVID-19: In addition, we infer the composition of 22 immune cells (see Methods: Upper airway samples from COVID-19 patients and controls) in samples and found the proportions of activated CD4+ memory T cells (CD4m T) and M1 Mø were increased in SARS-CoV-2 ARIs compared to non-viral ARIs and significantly associated with increased viral load (Figure 2A, Supplementary Figure S1), while the proportions of activated mast cells and neutrophils were decreased in SARS2-CoV-2 ARIs (Supplementary Figure S1).