IRF3 and infection: Thus, while human host resistance to HCV, as well as the responsiveness of an individual to DAA therapy, is closely tied to specific alleles of the interferon lamda 3 (IFNL3) gene for subjects with HCV genotype 3 infection [24], the importance of IFNA/IFNB is underlined by the fact that the NS3/4a protease of HCV disrupts two distinct upstream inputs that activate interferon regulatory factor 3 (IRF3) and type 1 IFN.