Differential expression of innate immune response genes in clinical phases of chronic hepatitis B infection

We investigated innate immune gene expression in clinical phases of chronic hepatitis B infection, including immune tolerant (IT), immune active (IA), inactive carrier (IC) and hepatitis B e antigen (HBeAg)-negative phases, as well as healthy controls. Expression levels of interferon types I, II and III, their receptor subunits, IRFs, TLRs and other IFN-induced genes in peripheral blood mononuclear cells were compared. Forty HBsAg-positive treatment-naïve subjects without co-infection with HIV, HCV or HDV were enrolled. To complement the viral load, the expression levels of 37 innate immune genes were measured by qPCR. The highest response of the innate immune system was observed in the IT and HBeAg-negative phases, and the IC phase had the lowest response; 31 of the 37 studied genes reached their maximum mRNA expression levels in the IT and HBeAg-negative phases, and the minimum expression levels of 23 genes were found in the IC phase. The highest mRNA expression levels of IFNs, IFN receptor subunits, IRFs and TLRs genes in all clinical phases were IFN-λ2 and 3, IFN-γR2, IRF7 and TLR7, and the lowest levels of mRNA expression were observed for IFN-α, IFN-λR1, IRF8 and TLR2. We conclude that innate immune response genes are expressed differentially among chronic HBV phases, and this difference may help to develop new precise and noninvasive methods to determine the progression of disease in chronic HBV patients.