Other epithelial and immune cell types display a similar pattern: broad IFN-responsive genes (largely type I specific) are strongly upregulated among cells from mild or moderate COVID-19 participants, while cells from severe COVID-19 participants upregulate few shared markers with mild or moderate COVID-19 participants, and instead skew toward inflammatory genes (S100A8, S100A9) (Figures 3E–3H, S3J–S3L, and 4C). The gene discussed is S100A9; the disease is COVID-19.