Six human PGs were identified as differentially expressed across the three subsets based on COVID-19 severity: Cytokeratin-4, ADP-ribosylation factor 4, Ig lambda chain V-I region HA, Protein S100-P, Sodium/glucose cotransporter 1, and Ig mu chain C region (Supplementary File 4). This evidence concerns the gene SLC5A1 and COVID-19.