KLK4 and infection: In our study, the significant upregulation of interferon-stimulated genes (ISGs) such as IFIT1, IFIT2, IFIT3, and MX1 in response to IAV and PIV3 infections aligns with findings by Jakwerth et al. [33], who report a broad and strong upregulation of genes related to the kinin-kallikrein system (KKS) in the context of SARS-CoV-2 infection.