Furthermore, the up-regulation of STAT1 and STAT2 in the high viral load lung samples compared to the low viral load lung samples of DEHGsCOVID-19 supports our finding of Cluster 1 upstream regulators (Figures 3C, 6B).The Cluster 1 and these five upstream regulators are collectively referred to as “host response signature network”, which was used for the detailed understanding of the regulatory mechanism of cytokine storm, host immune response, and clinical manifestation in COVID-19. The gene discussed is STAT1; the disease is COVID-19.