Pegylated interferons for chronic hepatitis B.
ABSTRACT Conventional interferon therapy has been used for the treatment of chronic hepatitis B (CHB) for many decades. However, the use of interferon has been limited by its short half-life and high incidence of dose-related side effects. A meta-analysis investigating the short- and long-term consequences of interferon therapy showed that, whilst interferon therapy was beneficial in the short term, resulting in normalization of alanine aminotransferase (ALT) levels, loss of HBeAg, 'e' seroconversion and suppression of hepatitis B virus (HBV) DNA, the long-term benefits were less substantial. Pegylation of interferon (peginterferon alpha-2a [40 kDa]) led to improved pharmacokinetic and pharmacodynamic profiles, which translated to superior efficacy compared with conventional, nonpegylated interferon, in the treatment of chronic hepatitis C. A phase II study investigated the safety and efficacy of peginterferon alpha-2a (40 kDa) in the treatment of chronic hepatitis B. The results demonstrated a rapid and dramatic reduction in HBV DNA levels, HBeAg clearance and normalization of ALT with peginterferon alpha-2a (40 kDa) compared with conventional interferon. Furthermore, peginterferon alpha-2a (40 kDa) conferred a notably improved treatment response in patients with 'difficult-to-treat' hepatitis B infection. In conclusion, peginterferon alpha-2a (40 kDa) is a promising emerging therapy for CHB.
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ABSTRACT: SUMMARY & CONCLUSION HBV is a Hepatotropic DNA-containing virus, discovered in 1966 by Blumberg. The virion of hepatitis B (Dane particle) consists of surface and core with a diameter of 42 nm (Kumar and Agrawal, 2004). The protein composition of HBV particles; either surface protein (HBs proteins) composed of LHBs (largest Hepatitis B proteins), MHBs (middle Hepatitis B proteins), SHBs (small Hepatitis B proteins) or core proteins; composed of HBc protein and HBe protein. The world health organization (WHO, 2004) estimated that 2 billion people have been infected by HBV worldwide; of these more than 300 millions are chronically infected carriers of whom 25% are at risk of serious illness and eventually death from cirrhosis or hepatocellular carcinoma. The prevalence of HBV infection varies markedly throughout regions of the world; highly endemic in South East Asia, moderately endemic in Eastern and Southern Europe and low endemic areas as in North America (Tsai, 2004). Concerning transmission of HBV; there is peri-natal transmission, sexual contact, blood and blood products, parentral drug abuse, opportunities for parentral infection, transmission in high endemic areas, exposure of unknown origin is still present. As regards clinical presentation and sequelae; HBV can present as acute infection, fulminant hepatic failure (FHF), chronic hepatitis, extra-hepatic manifestations, post hepatitis B cirrhosis or combinations with HDV or HCV. Occult HBV infection is characterized by the presence of HBV infection with undetectable hepatitis B surface antigen (HBsAg). Concerning the diagnosis of acute and chronic hepatitis B; the advances in molecular biology techniques led to the development of hybridization and polymerase chain reaction (PCR) assays for direct determination of HBV DNA. The diagnosis of HBV infection can also be made by the detection of HBsAg or HBcAg in liver tissues by immunohistochemical staining and of HBV DNA by Southern hybridization, in-situ hybridization, or PCR. Treatment of chronic hepatitis B include Interferon therapy, nucleoside analogues such as Lamivudine, Adefovir Dipivoxil, Entecavir, Famciclovir, Emtricitabine/ coviracil, Combination therapy, Therapeutic vaccine, Gene therapy and Immunotherapy. Prophylaxis against viral B infection is highly recommended using vaccination alone or combined with hepatitis B immunoglobulin for infants and individuals at risk of exposure.
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ABSTRACT: Size exclusion PEGylation reaction chromatography was investigated using a model developed by Fee (2005). Column dispersion was neglected and the PEGylation reaction was modelled as second order. The model allowed up to four PEG groups to be attached to a protein and accounted for succinic acid hydrolysis from activated PEG. The model was adapted to simulate a-lactalbumin PEGylation and succinic acid hydrolysis from activated PEG in a batch stirred tank so rate parameters from stirred tank kinetic experiments could be obtained and the model verified. The model was solved using finite differences and simulations run in Matlab. The effect of reaction parameters such as timing, length and concentration of PEG and protein injection, reaction rates, and model resolution on model simulation results was explored. In the size exclusion PEGylation simulations it was found that increasing protein concentration increased MonoPEG concentrations and increased the ratio of MonoPEG to starting protein feed concentration. Increasing PEG pulse length and starting PEG concentration initially increased MonoPEG concentration and product ratio until all protein had been PEGylated at which point MonoPEG concentration the product ratio levelled out. Increasing PEG hydrolysis rates did not affect the amount of MonoPEG produced but reduced the activated PEG concentration and increased succinic acid concentration. Optimal conditions for producing MonoPEG were found to be equal concentrations of PEG and protein, with the PEG injection length twice as long as the protein injection, and the PEG injection done immediately after the protein injection.
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ABSTRACT: γδ T cells play an important role in infectious, autoimmune, or neoplastic diseases. Here, a study was conducted to investigate the dynamic changes in phenotype and function of peripheral γδ T cells in patients with chronic hepatitis B (CHB) during pegylated-interferon (pegIFN)-α treatment, and to explore their roles in IFN-α therapy. Total 15 CHB patients with pegIFN-α therapy and 6 healthy controls (HC) were enrolled in this study. Flow cytometry was used for the study of frequency of peripheral γδ T cells, subtypes, effector or memory γδ T cells, and also the IFN-γ+, TNF-α+, CD107a+ or Granzyme B+ γδ T cells in 10 patients at week 0, 4, 8, 12, 24, 36 and 48 of treatment. Another 5 CHB patients and 6 HC were recruited for the γδ T cell isolation, and gene expression in γδ T cells was evaluated before or after IFN-α treatment in vitro. Although γδT cells decreased in CHB patients during pegIFN-α therapy, their capacities to produce TNF-α and to express CD107a were enhanced. More effector γδT cells (CD27-CD45RA+) were found in the response group than in non-response group. Furthermore, IFN-α boosted the expression of Mx2 and cytokine genes in γδT cells from CHB patients in vitro. IFN-α could enhance the cytokine production or cytotoxicity potential of γδT cells in vivo and in vitro. The enhanced function of γδT cells might contribute to the effect of IFN-α treatment.PLoS ONE 03/2015; 10(3):e0120086. DOI:10.1371/journal.pone.0120086 · 3.53 Impact Factor