SPDEF and COVID-19: In goblet cells, STAT2 and KLF5 were highly activated and upregulated in many genes with mild/moderate COVID-19, such as ISGs (PARP14 and IFI44L), whereas ELF3, SBP1, NR2F6, and SPDEF were preferentially activated in severe COVID-19 to regulate the expression of their targets (Figure 2A).