IL17A and COVID-19: In particular, IL17A-induced genes SAA1, SAA2, SAT1, LCN2, S100A8, and GLUL were repeatedly significantly upregulated among diverse epithelial cell subsets in severe COVID-19 (Fig. 4A through C) but were not found to be significantly induced within the nasal epithelia of patients with milder COVID-19 (Fig. S3B).