Interferon alpha induces a stronger antiviral effect than interferon lambda in HBV/HDV infected humanized mice

Recent studies indicate that treatment of chronic hepatitis D virus (HDV) with either pegylated interferon (IFN)λ or pegylated IFNα monotherapy leads to a dramatic decline in HDV RNA. Herein, we investigated the innate antiviral efficacy of IFNλ and IFNα in humanized mice that lack an adaptive immune response. Humanized mice were either co-infected with hepatitis B virus (HBV) and HDV simultaneously, or HDV infection was performed subsequent to HBV infection (i.e., superinfected). After steady viral replication was achieved, mice received either IFNλ (n = 6) or IFNα (n = 7) for 12 (or 13) weeks. Pretreatment median levels of serum HBV DNA (8.8 [IQR:0.2] log IU/ml), HDV RNA (9.8 [0.5] log IU/ml), HBsAg (4.0 [0.4] log IU/ml) and human albumin, hAlb (6.9 [0.1] log ng/mL) were similar between mice treated with IFNα or IFNλ and between those coinfected versus superinfected. Compared to mice treated with IFNλ, mice treated with IFNα had a significantly greater decline in HBV, HDV, and HBsAg levels. In conclusion, IFNα induces stronger inhibition of HBV and HDV than IFNλ in humanized mice that lack an adaptive immune response. Further studies are needed to assess the respective role of the combined innate-and adaptive-immune systems in the treatment of HBV and HDV with IFNα and IFNλ.