XBP1 and infection: By comparing nasopharyngeal swabs and PBMCs, we found that there were notable differences between the many identified regulons among conditions or infection sites (i.e., nasal or peripheral blood), while some were found to be shared, and XBP1, FOS, STAT1, and STAT2 were activated in both the epithelial and peripheral immune cells of virus-infected individuals (Figure 1B).