IFITM1 and long COVID-19: Hospitalized PASC participants exhibited increased expression of numerous interferon stimulated genes (ISGs), including CMPK2, IFI44L, USP18, IFI44, XAF1, IRF7, IFITM1, BST2, DDX58, JAK2, STAT2, and IRF8, specifically in the DN1 B cell subset, during acute SARS-CoV-2 infection (Figure 3D).