The Preliminary Study Of Interferon Signal Pathway In Difficult To Treat Chronic Hepatitis B Patients

HBV infection and chronic hepatitis B (CHB) remains the significant public health problems in China as well as worldwide. Effective antiviral treatment has been shown to significantly reduce the occurrence rate of liver cirrhosis and hepatocyte cellular carcinoma (HCC). However, limited antiviral effectiveness has been achieved with currently available antiviral drugs including nucleotide analogues and interferons. Thus studies have been dedicated to illustrate the underlined mechanisms contributing to the effectiveness of antiviral therapy. This in turn may shed light to new strategies for patients management.Interferons have broad-spectrum antiviral, immunomodulatory function. In vitro studies have shown that interferon binds to the receptor of cell surface and activates the classical JAK-STAT pathway and many signal molecules, thus inducing antiviral protein to play the antiviral action, with 2',5'-OAS and Mx as key components of the entire pathway. Mx protein is a protein induced by type I interferon and distributes in the cytoplasm. It has broad-spectrum antiviral activity. The Mx protein is sensitive to orthomyxoviridaevirus, paramyxovirus, small RNA virus and HBV . The 2',5'-OAS can activate the nucleic acid hydrolysis enzyme and play an anti-virus role through selectively degrading mRNA. In patients with CHB, the molecular mechanism of interferon exerting its antiviral and immunomodulatory function is not fully understood. This current study is aimed to investigate the molecule mechanism involved in the effectiveness if IFN treatment in difficult to treat CHB patients, mainly focused on interferon induced signaling pathways and antiviral molecules both in vitro and in vivo.Two cell lines, HepG 2.2.15 cell with HBV replication and HepG2 cells without HBV replication were introduced to in vitro studies. Compared with baseline, the Mx and 2',5'-OAS expression in both HepG2 and HepG2.2.15 cells increased at 6 hour,12 hour,24 hour post IFN treatment and peaked at 6 hour as measured by Realtime PCR. Further more, the expression were significantly higher in HepG2 cell when compared with HepG 2.2.15 where HBV replication happens. These data suggested that HBV replication interferes the IFN induced antiviral molecule production.Parallely, the IFN induced signaling pathway was also investigated in difficult to treat patients. These patients have experienced entecavir therapy for 9 to 36month with the achievement of HBV DNA negativity but with no HBeAg serum conversion. Forty patients were randomized to group A and B with 20 in each group. Patients in group A received a two month of combination of entecavir plus Peg-IFN- alpha 2a treatment followed by a total duration of 48weeks Peg-IFN- alpha 2a, while group B continued entecavir treatment. PBMCs were isolated at baseline week 4, 12, 24 post treatment. The expression of signal molecule and antiviral proteins including Mx, 2 ', 5 '- OAS significantly increased at both mRNA and protein levels while remain unchanged with continuous entecavir treated patients indicating IFN triggled the downstream signaling pathway in these difficult to treat patients. Whether this effect will transform to clinical benefit requires further observation in this study.