Mutations in Pol gene of hepatitis B virus in patients with chronic hepatitis B before and after therapy with nucleoside/nucleotide analogues.

Chronic hepatitis B (CHB) is one of the most common infections worldwide. Currently approved treatments of CHB include nucleoside/nucleotide analogues (NAs). However, long-term NA therapy is associated with accumulation of resistant mutations within the hepatitis B virus (HBV) polymerase gene. The incidence of naturally occurring HBV mutations leading to primary antiviral resistance has not been fully elucidated yet. The objective of present study was to detect the frequency of mutations within the HBV polymerase gene in 263 patients naïve to nucleoside/nucleotide analogues. Prevalence of HBV Pol gene mutations secondary to NA treatment in patients without pre-existing antiviral resistance mutations was also examined. Retrospective analysis showed that HBV Pol gene mutations were present in 7 out of 263 patients prior to the treatment. Mutations observed in NA-naïve CHB patients were associated only with resistance to lamivudine and adefovir. Compensatory mutations were observed as well. In the course of antiviral treatment, HBV Pol gene mutations were identified in 65 out of the remaining 256 CHB patients (25.39%), while no mutations of any type were detected in 160 patients (62.5%). The profiles of detected mutations were comparable to those observed in other studies that focused on the analysis of clinically relevant NA-resistant mutations. In conclusion, we found out that antiviral resistance mutations may pre-exist in the overall viral population present in untreated patients, although the incidence of HBV Pol gene mutations in NA-naïve CHB patients was low and reached only up to 2.66%. However, possible circulation and transmission of NAs-resistant HBV mutants in human population should be taken into account.

Early virological response in children with chronic hepatitis C treated with pegylated interferon and ribavirin.

OBJECTIVE: Infection with hepatitis C virus (HCV) is widespread worldwide. It is estimated that this problem affects approximately 3% of global population. By introducing weekly doses of pegylated interferon (IFN) alfa in combination with ribavirin, given daily, to chronic hepatitis C (CHC) treatment one can achieve a full inhibition of HCV replication in 54-56% of adult patients. The aim of this study was to examine the relationship between prognostic factors and early virological response (EVR) after combination treatment with peginterferon alfa- 2a or alfa-2b and ribavirin in children with CHC. METHODS: Twenty-three children with chronic HCV were treated with a combination of peginterferon alfa-2a or alfa-2b once a week and ribavirin twice a day. Assessment included age at the time of infection, the length of infection, HCV genotype, viral load in serum and HCV RNA level in peripheral blood mononuclear cells (PBMCs), alanine aminotransferase (ALT) activity and adherence to therapy. The efficacy endpoint was EVR defined as undetectable HCV RNA in serum or >2 log10 decrease in HCV RNA compared with baseline values. RESULTS: An EVR was achieved in 15 out of 23 patients (65.3%) after 12 weeks of therapy. CONCLUSIONS: Lower HCV RNA viral load have positive influence on EVR. HCV RNA presence in PBMCs and lower ALT activity do not influence the achievement of EVR. Oncologic history does not bear any influence on EVR. Adherence to the therapy has an unclear influence on the achievement of EVR in children with CHC.

Tissue localization of Toll-like receptors in biopsy specimens of liver from children infected with hepatitis C virus.

Toll-like receptors (TLR) are important tools of innate immunity, localized mainly on cells of the immune system, but also have been shown on cells of other origin. In the current study, they have been searched in biopsy specimens of liver from children bearing chronic viral hepatitis of C type (HCV). TLR2, TLR3 and TLR4 were traced by means of polyclonal antibodies and avidin-biotin complex (ABC) immunohistochemistry. Besides, mRNA for TLR was looked for using specific primers and polymerase chain reaction. Several controls, including neutralization of primary antibody with respective blocking peptide, confirmed the specificity of the immunohistochemical reaction. All TLR tested could be visualized in a focal distribution in single hepatocytes and some cells of inflammatory infiltrates. There was no reaction whatsoever in liver samples not infected with hepatotropic virus. In molecular studies, mRNA for TLR2 and TLR4 was detected in both noninfected and hepatitis B virus-infected established cell lines of human hepatoma as well as in HCV(+) biopsy samples. These data indicate that TLR can be traced in liver cells, both at the protein and at the mRNA level. Their irregular and focal distribution in HCV(+), but not in HCV(-), liver suggests some role of TLR in the pathogenesis of chronic viral hepatitis, at least in children.