IRF9 and infectious disease: Overall, the natural course of infectious diseases in the known patients with inherited deficiencies of IRF1 (this study), IRF3152,153, IRF7138,140, or IRF9139,154 suggests that IRF1 is essential for IFN-γ-dependent myeloid antimycobacterial immunity, whereas IRF3, IRF7 and IRF9 are essential for IFN-α/β-dependent antiviral immunity.