Hepatitis B virus epidemiology, disease burden, treatment, and current and emerging prevention and control measures

Hepatitis B Virus Replication and Liver Disease Progression: The Impact of Antiviral Therapy

Chronic hepatitis B virus (HBV) infection is a serious health issue worldwide. The presence of HBV replication markers — hepatitis B e antigen (HBeAg) or HBV DNA — is associated with continuing hepatitis activity or intermittent hepatitis flares and subsequent disease progression, including hepatic decompensation and development of liver cirrhosis or hepatocellular carcinoma (HCC). Long-term (>10 years) prospective studies in patients ≥30 years of age have shown that HBeAg seropositivity is associated with increased risk of disease progression, and the risk of cirrhosis and HCC begins to increase at an HBV DNA level of 104 copies/ml. Therefore, elimination of HBV, or at least sustained or maintained suppression of HBV, is the key to reducing hepatitis and thereby halting or preventing disease progression. Therapy with interferon-α or a direct antiviral agent has been shown to reduce the risk of cirrhosis and prevent further disease worsening. In both the woodchuck hepatitis model and in HBV patients, maintained suppression of HBV replication by a direct antiviral agent may reduce the progression to HCC. However, the efficacy of current antiviral therapy is still far from satisfactory. The ability to achieve a high rate of sustained or maintained HBV suppression with a low risk of drug resistance would be the ultimate goal in the treatment of chronic HBV infection.

Characterization of bioactive recombinant woodchuck interleukin-2 amplified by RLM-RACE and produced in eukaryotic expression system

Woodchucks (Marmota monax) infected with woodchuck hepatitis virus (WHV) represent a highly valuable laboratory model of hepatitis B virus (HBV) infection, in which molecular, immunological and pathological events occurring in infected humans are adequately reflected. To advance studies on T cell immune responses and propagation of hepadnavirus in T lymphocytes in this animal model, we determined the complete sequence of woodchuck interleukin-2 (wIL-2) cDNA by utilizing RNA ligase-mediated rapid amplification of cDNA ends (RLM-RACE) reaction. The wIL-2 sequence revealed a single open reading frame encoding for the predicted precursor protein comprised of a signal peptide and a 134 amino acid-long mature protein. The mature wIL-2 protein produced in the Escherichia coli expression system, designated as ec-rwIL-2, was found to be immunogenic but not biologically active. In contrast, precursor wIL-2 protein cloned into baculovirus transfer vector and expressed in Sf9 cells, designated as bac-rwIL-2, demonstrated functional competence. Further, bac-rwIL-2 was able to stimulate proliferation and to induce multiple daughter cell generations in woodchuck T cells, as well as facilitated the survival of standard IL-2-dependent mouse CTLL-2 cells in culture. Western blot analysis of bac-rwIL-2 using antibodies generated against ec-rwIL-2 revealed a single protein band of 15.5kDa. The availability of biologically active recombinant wIL-2 should facilitate ex vivo studies on functional competence of woodchuck T lymphocytes derived from different stages of hepadnaviral hepatitis and assist in recognizing their contribution to the pathogenesis of liver injury in the woodchuck model of hepatitis B.

Lack of association between acute exposure to ionizing radiation and liver cirrhosis

PURPOSE

Although previous studies have shown significantly increased risks of liver cirrhosis and chronic liver disease for acute radiation exposure among survivors of the atomic bombings of Hiroshima and Nagasaki, Japan, these studies have not taken into account hepatitis B virus (HBV) infections. Because HBV is associated with both A-bomb radiation and liver cirrhosis, our goal was to investigate the relationship of acute ionizing radiation to liver cirrhosis adjusting for HBV, co-occurring primary liver cancer (PLC), and other potential confounders.

MATERIALS AND METHODS

Using a cross-sectional design and pathology review of a cohort of Japanese atomic-bomb survivors, we found that 213 of 335 (63.6%) subjects with PLC and 55 of 776 (7.1%) subjects without PLC had cirrhosis.

RESULTS

We found no association between acute exposure to A-bomb radiation and liver cirrhosis. The adjusted odds ratio of cirrhosis per Sv liver irradiation was 0.59 (95% confidence interval: 0.27 - 1.27). Cirrhosis risks for the highest tertile of radiation exposure (mean exposure 0.7 Sv) were also not elevated (0.8, 0.26 - 2.12 and 0.2, 0.03 - 0.98 among subjects with and without PLC.

CONCLUSIONS

Acute exposure to liver irradiation does not increase risks of liver cirrhosis, regardless of PLC status.

Synthesis and Anti-Hepatitis B Virus Activity of Novel Benzimidazole Derivatives

A series of novel benzimidazole derivatives was synthesized and evaluated for their anti-hepatitis B virus (HBV) activity and cytotoxicity in vitro. Strong activity against HBV replication and low cytotoxicity were generally observed in these benzimidazoles. The most promising compounds were 12a and 12b, with similar high antiviral potency (IC50 = 0.9 and 0.7 microM, respectively) and remarkable selectivity indices (>1111 and 714, respectively). They were selected for further evaluation as novel HBV inhibitors.

[Microbiological diagnosis of viral hepatitis]

Hepatitis of viral aetiology caused by hepatotropic virus (A, E, B, D and C) represents an important work load for the clinical virology laboratory. Most of the diagnostic is based upon detection in serum and plasma samples of different serological and virological markers, which correlates with different infection stages. In chronic infection by HBV and HCV is necessary to perform diagnostic by molecular methods as well as antigen detection in sequential samples along the course of the disease taking into account that a reliable storage must be provided for stability of structural components of the virus. Recent knowledge about mutations variants in some of the virus may alter the validity of particular markers.

Immunization coverage and risk factors for failure to immunize within the Expanded Programme on Immunization in Kenya after introduction of new Haemophilus influenzae type b and hepatitis b virus antigens

Background

Kenya introduced a pentavalent vaccine including the DTP, Haemophilus influenzae type b and hepatitis b virus antigens in Nov 2001 and strengthened immunization services. We estimated immunization coverage before and after introduction, timeliness of vaccination and risk factors for failure to immunize in Kilifi district, Kenya.

Methods

In Nov 2002 we performed WHO cluster-sample surveys of >200 children scheduled for vaccination before or after introduction of pentavalent vaccine. In Mar 2004 we conducted a simple random sample (SRS) survey of 204 children aged 9–23 months. Coverage was estimated by inverse Kaplan-Meier survival analysis of vaccine-card and mothers' recall data and corroborated by reviewing administrative records from national and provincial vaccine stores. The contribution to timely immunization of distance from clinic, seasonal rainfall, mother's age, and family size was estimated by a proportional hazards model.

Results

Immunization coverage for three DTP and pentavalent doses was 100% before and 91% after pentavalent vaccine introduction, respectively. By SRS survey, coverage was 88% for three pentavalent doses. The median age at first, second and third vaccine dose was 8, 13 and 18 weeks. Vials dispatched to Kilifi District during 2001–2003 would provide three immunizations for 92% of the birth cohort. Immunization rate ratios were reduced with every kilometre of distance from home to vaccine clinic (HR 0.95, CI 0.91–1.00), rainy seasons (HR 0.73, 95% CI 0.61–0.89) and family size, increasing progressively up to 4 children (HR 0.55, 95% CI 0.41–0.73).

Conclusion

Vaccine coverage was high before and after introduction of pentavalent vaccine, but most doses were given late. Coverage is limited by seasonal factors and family size.

Inhibiting effects of root of Mallotus apelta on duck hepatitis B virus

OBJECTIVE

To evaluate the inhibiting effects of the root of Mallotus apelta (Lour.) Muell.-Arg. on duck hepatitis B virus (D-HBV) in vivo.

METHODS

Forty nestling ducks with congenitally infection of D-HBV detected by PCR were randomly divided into five groups: untreated group, lamivudine-treated group, and high-, medium- and low-dose root of Mallotus apelta-treated groups. The ducks in the lamivudine-treated group were fed lamivudine with a dose of 50 mg/kg once. Ducks in the three-dose Mallotus apelta-treated groups were treated with different doses of decoction of this herbal medicine for 21 days respectively. The serum content of D-HBV DNA was determined by quantitative real-time PCR technique before and 7 days after the treatment, and on the 7th, 14th and 21st day of the treatment. Liver biopsy was also executed before and after the treatment to observe the histopathological changes.

RESULTS

Lamivudine showed a rapid inhibiting effect on D-HBV DNA, but this effect didn't last long, and the serum level of D-HBV DNA increased again after treatment. The serum level of D-HBV DNA dropped markedly in the high- and medium-dose Mallotus apelta-treated groups on the 14th and 21st day. Low-dose Mallotus apelta revealed no obvious inhibiting effect on D-HBV. After treatment, the inhibiting effect in the root of Mallotus apelta-treated group continued as compared with that in the untreated group. The histopathological changes of liver tissues showed that the inflammation in the high-dose root of Mallotus apelta-treated group was weakened as compared with that in the lamivudine-treated group.

CONCLUSION

The root of Mallotus apelta has therapeutic effect on D-HBV. It can restrain the duplication of D-HBV in vivo. Although this effect is weaker than that of lamivudine, it continues longer. Thus this herbal medicine is an effective, safe and economical drug for hepatitis B.

Emerging therapeutics for chronic hepatitis B

Hepatitis B is a global health problem. Patients with chronic hepatitis B (CHB) carry a significant risk to eventually develop cirrhotic liver disease. Recent therapeutic advances against CHB offer excellent potential for long-term suppression of hepatitis B virus (HBV) replication during antiviral therapy, and occasionally a durable remission off medication. Selection of appropriate patients for antiviral therapy depends on identification of HBV replication and an elevated alanine aminotransferase level or histologic liver injury. Pegylated interferon alpha offers potent immunomodulatory and antiviral activity with the potential for durability, but also with adverse effects and significant cost. The nucleoside or nucleotide analogs, lamivudine, adefovir, and entecavir, suppress HBV replication and are extremely well-tolerated, but long-term or even lifelong therapy is required. Most experience has been gained with lamivudine, but viral resistance occurs frequently. Newer analogs appear to be relatively free of this problem. Approaches using a combination of agents have promise, but have yet to be proven superior to individual drugs alone.

Seropositivity for hepatitis B virus, vaccination coverage, and vaccine response in dentists from Campo Grande, Mato Grosso do Sul, Brazil

This study investigated the seropositivity for hepatitis B virus (HBV), the vaccination index, and the vaccine response index in dentists from Campo Grande, MS. Blood samples from 474 dentists (63.7% women and 36.3% men), with a mean age of 38.5 +/- 10.5 years were analyzed by enzyme-linked immunosorbent assay to detect the serological markers: HBsAg, anti-HBs, and anti-HBc. The HBsAg positive samples were tested for anti-HBc IgM, HBeAg, and anti-HBe. A total of 51 (10.8%) dentists showed seropositivity for HBV. Three (0.6%) were HBsAg/anti-HBc/anti-HBe positive, 43 (9.1%) were anti-HBc/anti-HBs positive, and 5 (1.1%) had only anti-HBc. Viral DNA was detected by polymerase chain reaction in 9 (17.6%) out of 51 HBV seropositive samples. A vaccination index of 96.6% (458/474) was observed, although 73.1% (335/458)completed the three-dose schedule. Excluding 46 HBV seropositive individuals from 458 that reported vaccination, 412 were analyzed for vaccine response index. It was observed that 74.5% (307/412) were anti-HBs positive; this percentage increased to 79.1% when three doses were administered. The results showed a high vaccination index and a good rate of vaccine response; however, the failure in completing the three-dose schedule and the occurrence of HBV infection reinforce the need for more effective prevention strategies.

DNA vaccines expressing the duck hepatitis B virus surface proteins lead to reduced numbers of infected hepatocytes and protect ducks against the development of chronic infection in a virus dose-dependent manner

We tested the efficacy of DNA vaccines expressing the duck hepatitis B virus (DHBV) pre-surface (pre-S/S) and surface (S) proteins in modifying the outcome of infection in 14-day-old ducks. In two experiments, Pekin Aylesbury ducks were vaccinated on days 4 and 14 of age with plasmid DNA vaccines expressing either the DHBV pre-S/S or S proteins, or the control plasmid vector, pcDNA1.1Amp. All ducks were then challenged intravenously on day 14 of age with 5 x 10(7) or 5 x 10(8) DHBV genomes. Levels of initial DHBV infection were assessed using liver biopsy tissue collected at day 4 post-challenge (p.c.) followed and immunostained for DHBV surface antigen to determine the percentage of infected hepatocytes. All vector vaccinated ducks challenged with 5 x 10(7) and 5 x 10(8) DHBV genomes had an average of 3.21% and 20.1% of DHBV-positive hepatocytes respectively at day 4 p.c. and 16 out of 16 ducks developed chronic DHBV infection. In contrast, pre-S/S and S vaccinated ducks challenged with 5 x 10(7) DHBV genomes had reduced levels of initial infection with an average of 1.38% and 1.93% of DHBV-positive hepatocytes at day 4 p.c. respectively and 10 of 18 ducks were protected against chronic infection. The pre-S/S and the S DNA vaccinated ducks challenged with 5 x 10(8) DHBV genomes had an average of 31.5% and 9.2% of DHBV-positive hepatocytes on day 4 p.c. respectively and only 4 of the 18 vaccinated ducks were protected against chronic infection. There was no statistically significant difference in the efficacy of the DHBV pre-S/S or S DNA vaccines. In conclusion, vaccination of young ducks with DNA vaccines expressing the DHBV pre-S/S and S proteins induced rapid immune responses that reduced the extent of initial DHBV infection in the liver and prevented the development of chronic infection in a virus dose-dependent manner.

High affinity mouse-human chimeric Fab against hepatitis B surface antigen

AIM

Passive immunotherapy using antibody against hepatitis B surface antigen (HBsAg) has been advocated in certain cases of Hepatitis B infection. We had earlier reported on the cloning and expression of a high affinity scFv derived from a mouse monoclonal (5S) against HBsAg. However this mouse antibody cannot be used for therapeutic purposes as it may elicit anti-mouse immune responses. Chimerization by replacing mouse constant domains with human ones can reduce the immunogenicity of this antibody.

METHODS

We cloned the V(H) and V(L) genes of this mouse antibody, and fused them with CH1 domain of human IgG1 and C(L) domain of human kappa chain respectively. These chimeric genes were cloned into a phagemid vector. After initial screening using the phage display system, the chimeric Fab was expressed in soluble form in E. coli.

RESULTS

The chimeric Fab was purified from the bacterial periplasmic extract. We characterized the chimeric Fab using several in vitro techniques and it was observed that the chimeric molecule retained the high affinity and specificity of the original mouse monoclonal. This chimeric antibody fragment was further expressed in different strains of E. coli to increase the yield.

CONCLUSION

We have generated a mouse-human chimeric Fab against HBsAg without any significant loss in binding and epitope specificity. This chimeric Fab fragment can be further modified to generate a full-length chimeric antibody for therapeutic uses.

Inhibition of multiple gene expression and virus replication of HBV by stable RNA interference in 2.2.15 cells

BACKGROUND/AIMS

Hepatitis B virus (HBV) infection is a world-wide health problem. Recent studies have demonstrated the efficacy of RNA interference (RNAi) against HBV replication at cell culture and animal levels using transient transfection. The present study was to determine whether the stable transfection of short hairpin RNA (shRNA)-producing vector could achieve potent and sustained inhibition of the HBV replication in 2.2.15 cells.

METHODS

shRNA-producing vector against HBV and the empty vector were stably transfected into the 2.2.15 cells respectively. A series of experiments were performed in the producing stable lines to determine the changes of viral protein expression and replication.

RESULTS

The HBV protein expression and viral replication were suppressed dramatically and stably by the integrated shRNA-producing vectors. Most importantly, this suppression effect persists after 30 passages.

CONCLUSIONS

Our data provided the possibility of continuous and stable inhibition of HBV protein expression and replication in patients using RNAi, suggesting a potential clinical application of this novel approach. Furthermore, the established stable transfected cell lines provided a good platform for understanding the mechanism of anti-HBV by RNAi.

Serotonin transporter mRNA expression is decreased by lamivudine and ribavirin and increased by interferon in immune cells

Clinical reports document that depression as a side effect is more prevalent in hepatic patients given interferon (IFN)-alpha therapy than in those given lamivudine. The mechanisms, however, are poorly understood. Serotonin transporter (5-HTT), via uptake of serotonin (5-HT) into presynaptic serotoninergic neurons, is an initial action site for antidepressants. Real-time polymerase chain reaction (PCR) was used to quantify 5-HTT mRNA expression in immune cells in order to evaluate whether 5-HTT acted as an indicator of depression. Results showed that the 5-HTT mRNA expression was much higher in T-cell and B-cell lines than that in a monocytic cell line. Treatment with either lamivudine or ribavirin reduced the 5-HTT mRNA expression, protein level and 5-HT uptake in T-cell line. Treatment with IFN-alpha, however, increased those levels in the same group. A similar effect was observed in peripheral blood mononuclear cells (PBMC). Mimicking clinical use by treating PBMC with a combination of IFN-alpha and ribavirin increased the 5-HTT mRNA expression level. Our study indicates that these therapeutic drugs regulate 5-HTT expression, which implies that 5-HTT might be a trait marker in IFN-alpha-induced depression after hepatic therapy.

Entecavir versus lamivudine for patients with HBeAg-negative chronic hepatitis B

BACKGROUND

Entecavir is a potent and selective antiviral agent that has demonstrated efficacy in phase 2 studies in patients with hepatitis B e antigen (HBeAg)-negative chronic hepatitis B.

METHODS

In this phase 3, double-blind trial, we randomly assigned 648 patients with HBeAg-negative chronic hepatitis B who had not previously been treated with a nucleoside analogue to receive 0.5 mg of entecavir or 100 mg of lamivudine once daily for a minimum of 52 weeks. The primary efficacy end point was histologic improvement (a decrease by at least two points in the Knodell necroinflammatory score, without worsening of fibrosis).

RESULTS

Histologic improvement after 48 weeks of treatment occurred in 208 of 296 patients in the entecavir group who had adequate baseline liver-biopsy specimens that could be evaluated (70 percent), as compared with 174 of 287 such patients in the lamivudine group (61 percent, P=0.01). More patients in the entecavir group than in the lamivudine group had undetectable serum hepatitis B virus (HBV) DNA levels according to a polymerase-chain-reaction assay (90 percent vs. 72 percent, P<0.001) and normalization of alanine aminotransferase levels (78 percent vs. 71 percent, P=0.045). The mean reduction in serum HBV DNA levels from baseline to week 48 was greater with entecavir than with lamivudine (5.0 vs. 4.5 log [on a base-10 scale] copies per milliliter, P<0.001). There was no evidence of resistance to entecavir. Safety and adverse-event profiles were similar in the two groups.

CONCLUSIONS

Among patients with HBeAg-negative chronic hepatitis B who had not previously been treated with a nucleoside analogue, the rates of histologic improvement, virologic response, and normalization of alanine aminotransferase levels were significantly higher at 48 weeks with entecavir than with lamivudine. The safety profile of the two agents was similar, and there was no evidence of viral resistance to entecavir. (ClinicalTrials.gov number, NCT00035789.).

The current pattern of hepatitis B virus infection in Australia

There is little recent data of the seroprevalence of hepatitis B in Australia. We have surveyed a large cohort of endoscopy patients attending a teaching hospital in central Sydney, and related the presence of hepatitis B virus (HBV) markers with putative risk factors for exposure using the SAS statistical package. Of the 2115 patients tested: 2.1% (45/2115) were HBV surface antigen positive, 0.75% (14/2115) viraemic, 9.5% (200/2115) anti-HBs and anti-HBc positive, 20.1% (430/2115) vaccinated (anti-HBs only) and the remaining 70% were susceptible. The adjusted OR of HBV infection was significantly increased in patients who had been diagnosed with human immunodeficiency virus (36.3-fold), born in Asia or Pacific islands (12.4-fold), born in North Africa, Middle East & Mediterranean countries (6-fold) or born abroad elsewhere in the world (2.7-fold), had household contact with someone diagnosed with hepatitis between 1980 and 1990 (3.9-fold), injected drugs between 1980 and 1990 (4.4-fold), resided in a military establishment for 3 months (2.3-fold) or in a hospital for 3 months (2.2-fold), never been vaccinated for hepatitis B (2.8-fold), received blood transfusion due to an accident and/or a haemorrhage (1.92-fold) and finally been a male gender (1.59-fold). The prevalence of HBV in this hospital population was higher than predicted on the basis of notifications to the passive surveillance scheme. Most HBV patients had multiple risk factors for infection, but the hierarchy of odds ratios provides a rational basis for targeted programmes to identify asymptomatic HBV carriers who might benefit from treatment.

Coexistence of hepatitis B surface antigen (HBs Ag) and anti-HBs antibodies in chronic hepatitis B virus carriers: influence of "a" determinant variants

In chronic hepatitis B (CHB), the persistence of hepatitis B surface antigen (HBs Ag) is sometimes associated with antibodies (Ab) to HBs (anti-HBs). To assess the hypothesis of the selection of HBs Ag immune escape variants in CHB patients, the variability of the HBV S gene was determined for patients persistently carrying both HBs Ag and anti-HBs antibodies and patients solely positive for HBs Ag. We selected 14 patients who presented both markers (group I) in several consecutive samples and 12 patients positive for HBs Ag only (group II). The HBs Ag-encoding gene was amplified and cloned, and at least 15 clones per patient were sequenced and analyzed. The number of residue changes within the S protein was 2.7 times more frequent for group I than for group II patients and occurred mostly in the "a" determinant of the major hydrophilic region (MHR), with 9.52 versus 2.43 changes per 100 residues (P = 0.009), respectively. Ten patients (71%) from group I, but only three (25%) from group II, presented at least two residue changes in the MHR. The most frequent changes in group I patients were located at positions s145, s129, s126, s144, and s123, as described for immune escape variants. In CHB patients, the coexistence of HBs Ag and anti-HBs Ab is associated with an increase of "a" determinant variability, suggesting a selection of HBV immune escape mutants during chronic carriage. The consequences of this selection process with regard to vaccine efficacy, diagnosis, and clinical evolution remain partially unknown.

Vaccination of ducks with a whole-cell vaccine expressing duck hepatitis B virus core antigen elicits antiviral immune responses that enable rapid resolution of de novo infection

As a first step in developing immuno-therapeutic vaccines for patients with chronic hepatitis B virus infection, we examined the ability of a whole-cell vaccine, expressing the duck hepatitis B virus (DHBV) core antigen (DHBcAg), to target infected cells leading to the resolution of de novo DHBV infections. Three separate experiments were performed. In each experiment, ducks were vaccinated at 7 and 14 days of age with primary duck embryonic fibroblasts (PDEF) that had been transfected 48 h earlier with plasmid DNA expressing DHBcAg with and without the addition of anti-DHBcAg (anti-DHBc) antibodies. Control ducks were injected with either 0.7% NaCl or non-transfected PDEF. The ducks were then challenged at 18 days of age by intravenous inoculation with DHBV (5 x 10(8) viral genome equivalents). Liver biopsies obtained on day 4 post-challenge demonstrated that vaccination did not prevent infection of the liver as similar numbers of infected hepatocytes were detected in all vaccinated and control ducks. However, analysis of liver tissue obtained 9 or more days post-challenge revealed that 9 out of 11 of the PDEF-DHBcAg vaccinated ducks and 8 out of 11 ducks vaccinated with PDEF-DHBcAg plus anti-DHBc antibodies had rapidly resolved the DHBV infection with clearance of infected cells. In contrast, 10 out of 11 of the control unvaccinated ducks developed chronic DHBV infection. In conclusion, vaccination of ducks with a whole-cell PDEF vaccine expressing DHBcAg elicited immune responses that induced a rapid resolution of DHBV infection. The results establish that chronic infection can be prevented via the vaccine-mediated induction of a core-antigen-specific immune response.

Introduction to chronic hepatitis B infection

Chronic hepatitis B virus (HBV) infection affects over 350 million people worldwide and over 1 million die annually of HBV-related chronic liver disease. Although many individuals eventually achieve a state of nonreplicative infection, the prolonged immunologic response to infection leads to the development of cirrhosis, liver failure, or hepatocellular carcinoma (HCC) in up to 40% of patients. In endemic areas, where carrier rates are >5%, most individuals are infected perinatally, by vertical transmission, or in early childhood. In the United States, where prevalence is low except in particular areas and populations (e.g., Alaskan natives, immigrants from highly endemic areas), transmission is generally horizontal, percutaneous, or via sexual contact in adulthood. A variety of host (age at infection, gender, immune status); viral (viral load, genotype, mutation); and external (concurrent viral infections, alcohol consumption, chemotherapy) factors influence disease progression. Several variables (age at infection, gender, ethnicity, immune status) also influence the risk of chronic infection. Perinatal transmission, the most common mode of infection worldwide, can be reduced by appropriate prophylaxis (vaccination of the infant at birth together with hepatitis B immune globulin); anti-viral therapy in late pregnancy may also be beneficial. Five drugs are now FDA-approved for the treatment of HBV (interferon, lamivudine, adefovir, entecavir, and peginterferon alfa-2a), and suppressive anti-viral therapy improves the natural history of HBV. Patients with decompensated cirrhosis or HCC are highly likely to die unless they successfully undergo liver transplantation. While novel anti-viral drugs have improved the management of cirrhosis, strategies to prevent and treat HCC remain inadequate.

Prognostic analysis in chronic hepatitis B patients: a retrospective study of 216 cases about Scheuer scores, in situ expression of viral antigens and tissue hepatitis B virus DNA levels

BACKGROUND

Most of the previous studies of patients with chronic hepatitis B virus (HBV) infection concentrated on serum samples. Liver biopsy specimens for HBV have not been systematically analyzed. This study was performed to analyze some histopathological indicators (Scheuer scores, the expression of HBV antigens in situ, HBV DNA quantification) in the biopsy samples and showed the relationship among them and the prognosis of chronic hepatitis.

METHODS

A total of 216 consecutive chronic HBV-infected patients were followed up by clinical and laboratory data and classified into two groups at first: carcinogenesis and non-carcinogenesis. The non-carcinogenesis also included two groups: cirrhosis and non-cirrhosis. The non-cirrhosis was still divided into fluctuation and normalization at last. Histological activity index was described by Scheuer scores. Two-step immunohistochemical staining showed the expression of viral antigens in situ. Tissue HBV DNA levels were determined by fluorescence quantitative real-time PCR.

RESULTS

Regression analysis revealed significant positive correlations between the expression of hepatitis B e antigen (HBeAg) and grading, as well as between hepatitis Bx (HBx) protein and grading or staging of Scheuer scores. Positive correlations between grading or staging and prognosis were statistically significant. The expressions of HBeAg and HBx protein were higher in patients with cirrhosis than those without cirrhosis. Scheuer score was the most important indicator of prognosis.

CONCLUSIONS

HBeAg and HBx protein can be used as indicators of hepatitis activity and their positive expressions increase the risk for cirrhosis remarkably. In addition to be a marker of liver damage, Scheuer score is the most reliable indicator of the prognosis.

LAY BELIEFS ABOUT HEPATITIS AMONG NORTH AMERICAN CHINESE: IMPLICATIONS FOR HEPATITIS PREVENTION

The objective was to learn about the hepatitis prevention behavior of relatively unacculturated North American Chinese adults, along with their knowledge, beliefs, and perceptions with regard to hepatitis, screening, and vaccination. Forty Chinese men and women, aged 18-64, were recruited from immigrant communities in Seattle, Washington, and Vancouver, British Columbia. Semi-structured interviews (Cantonese or Mandarin) were audiotaped, translated, transcribed verbatim, and coded. Open coding, axial coding, constant comparison methods, and QSR NUD*IST 5 software was used for analysis. Findings were validated using eight focus groups. Findings indicated that many interviewees lack accurate knowledge with regard to hepatitis, often confusing the different types. Perceived causes of hepatitis included potentially harmful food (e.g., fried foods or potentially contaminated foods), alcohol, contact with infected individuals, stress, and inadequate rest. Preventive strategies associated with Chinese health beliefs included the use of Chinese herbal medicine, maintaining a stress-free mind, strengthening the body's natural defenses, and getting enough sleep. Other preventive strategies were the practice of good hygiene, vaccination, and the avoidance of contact with infected persons. Vaccination was not seen as primary, as 65% of those who had heard of hepatitis vaccination did not cite it as a means for hepatitis prevention until asked. Also, participants lacked information about the types and purposes of hepatitis vaccination and were worried about side effects. In conclusion, any attempt to promote hepatitis testing and vaccination among the North American Chinese should take traditional beliefs and practices into consideration.

Genotypic resistance to lamivudine among hepatitis B virus isolates in Mexico

BACKGROUND

Drug resistance of hepatitis B virus (HBV) is an increasing clinical problem. Resistance to lamivudine in HBV isolates in Mexico has been poorly explored.

OBJECTIVES

To characterize the mutation patterns associated with genotypic resistance to lamivudine and their prevalence among HBV isolates in Mexico.

MATERIAL AND METHODS

Thirty-nine Mexican HBV isolates were analysed by PCR and line probe assay for detection of genetic variants in the polymerase open reading frame domains B and C (INNO-LiPA HBV DR; INNOGENETICS N. V., Ghent, Belgium). This assay detects wild-type and mutations at codons 180, 204 and 207 of the HBV polymerase gene, and at codon positions 171, 172, 195, 196, 198 and 199 of the HBV surface antigen (HBsAg). HBV isolates were obtained from HBsAg-positive serum samples of 15 chronic hepatitis patients, two haemodialysis patients with chronic HBV carriage, 20 men found positive for HBsAg when seeking HIV testing and two AIDS patients with chronic HBV infection. None of the participants had received antiviral therapy.

RESULTS

Overall, HBV wild-type was found in 37 (94.9%) out of the 39 isolates studied. Two (5.1%) out of the 39 isolates showed mixed wild-type and mutant populations. These mutations occurred in isolates from one hepatitis patient and one haemodialysis patient. The isolate from the hepatitis patient showed a double mutation at codon positions 180 (L180M) and 204 (M204V), thus a 2.6% prevalence of genotypic resistance to lamivudine was found. The isolate from the haemodialysis patient showed a single mutation at codon position 180 (L180M). The two HBV mutant isolates were further analysed for genotype and both isolates were genotype H.

CONCLUSIONS

HBV genotypic resistance to lamivudine exists in Mexican isolates. The results highlight the importance of testing for HBV resistance before treatment and have implications for a more rational use of drugs.

Novel delivery methods for treatment of viral hepatitis: an update

Viral hepatitis represents the most common cause of chronic liver disease worldwide. Currently approved therapies for chronic hepatitis B include IFN, an immune modulator, and nucleoside analogues lamivudine and adefovir. For chronic hepatitis C, a combination of pegylated IFN-alpha and ribavirin represents the standard treatment. However, currently available treatments for both these viruses are effective only in a limited number of patients, are costly, prolonged, associated with significant side effects and require a substantial commitment from the patients and healthcare providers. A number of novel antiviral treatments, together with strategies to enhance the response to current therapies, are being explored at present. For all new therapies, as well as for improving existing treatments, selective delivery of medications into liver cells would be desirable to enhance antiviral activity and avoid systemic side effects. New achievements in the field of drug and gene delivery against chronic hepatitis to the liver are reviewed here.

Liver targeting of hepatitis-B antiviral lamivudine using the HepDirect prodrug technology

A new class of phosphate and phosphonate prodrugs, called HepDirect prodrugs, has been developed to deliver drugs to the liver while simultaneously diminishing drug exposure to extra-hepatic tissues. The technology combines liver-selective cleavage and kinase by pass with high plasma and tissue stability to achieve increased drug levels in the liver. Lamivudine (LMV), a nucleoside analogue, is a currently approved treatment for hepatitis B infection, but shows modest efficacy and significant drug resistance due to inefficient phosphorylation. LMV is inadequately phosphorylated to the corresponding nucleoside triphosphate in rat and human hepatocytes. A HepDirect prodrug of LMV monophosphate generated 34-fold higher levels of the triphosphate in rat hepatocytes and 320-fold higher triphosphate levels in the liver of treated rats relative to LMV.

Responsiveness to interferon alpha in chronic hepatitis B by presumed vertical transmission

This study was to evaluate responsiveness to IFN-alpha and investigate the benefits of sustained response (SR) in patients who were presumed as being vertically transmitted in Korea. A total of 46 patients of presumed vertical transmission with biopsy-proven HBeAg-positive chronic HBV infection were treated with IFN-alpha and followed. We tried to find the factors associated with SR and compared the cumulative rate of HCC and survival between SR group and non-sustained/non-responder (NSR) group. HBeAg loss was acquired in 35% (16/46) within a year but SR was observed in 22% (10/46). Age <35 years and ALT levels >7xULN were significant favorable factors for SR (OR 0.56, 0.49, 95%CI 0.38-0.82, 0.29-0.81, respectively) (both P<0.05). There were no significant differences of cumulative HCC-free survival (100 vs. 68% at 12 years, P=0.36) and survival (100 vs. 73% at 12 years, P=0.3) between SR group and NSR group. In conclusion, age below 35 years old and serum ALT levels above 7xULN may predict IFN-alpha therapy-induced SR among them, although we cannot affirm the effects on HCC prevention or survival.

A review of entecavir in the treatment of chronic hepatitis B infection

BACKGROUND

Infection with the hepatitis B virus (HBV) affects two billion people worldwide, and an estimated 400 million people are chronically infected. Currently, FDA-approved regimens for the treatment of chronic HBV include interferon-alpha2b, peginterferon-alpha2a, lamivudine, adefovir dipivoxil, and recently, entecavir.

OBJECTIVE

The purpose of this review is to evaluate the pharmacokinetic and pharmacodynamic properties, and the clinical efficacy and safety of entecavir in the treatment of nucleoside-naĩve and nucleoside-resistant HBeAg-positive and HBeAg-negative chronic hepatitis B (CHB). SEARCH METHODOLOGY: Computerized searches of PubMed and International Pharmaceutical Abstracts from 1985 to July 10, 2005, were performed with the search headings: entecavir, BMS-200475, and chronic hepatitis B.

FINDINGS

Entecavir, a new deoxyguanosine analog, represents a third agent within the nucleoside/nucleotide HBV polymerase inhibitor class with distinct advantages over lamivudine and adefovir dipivoxil: it has a three-step mechanism of action, is the most potent inhibitor of HBV DNA polymerase, is not associated with any major adverse effects, and has a limited potential for resistance. In phase II and III clinical trials, entecavir was found to be superior to lamivudine for all primary endpoints evaluated in both nucleoside-naïve and lamivudine-resistant patients. Entecavir was effective in both HBeAg-positive and HBeAg-negative nucleoside-naïve patients. At this time, optimal duration of entecavir therapy is unknown.

CONCLUSION

Entecavir represents a new first- or second-line treatment option for patients chronically infected with HBV. Long-term efficacy and safety studies as well as studies of entecavir in combination with interferon products or other nucleoside/nucleotide analogs are eagerly awaited.

Increased protein glycation in cirrhosis and therapeutic strategies to prevent it

Glycation of liver proteins by reactive aldehydes formed from the metabolism of ethanol and lipid peroxidation has been implicated in the development of both alcoholic and nonalcoholic liver cirrhosis. Modified proteins are targeted to the proteasome for proteolysis. Release of glycation-free adducts into the circulation may provide a diagnostic "signature" of hepatic protein damage. We quantitatively screened protein glycation, oxidation, and nitrosation adduct residues and free adducts in portal, hepatic, and peripheral venous blood plasma of cirrhotic patients; we also screened the hepatic and peripheral venous blood plasma of control subjects by liquid chromatography-mass spectrometry. There was a remarkable 14-16-fold increase of glyoxal-derived, hydroimidazolone-free adduct in portal and hepatic venous plasma of cirrhotic patients with respect to normal controls. There was only a twofold increase of glycation adduct residues in plasma proteins in cirrhotic patients, which was attributed mainly to decreased albumin turnover. Therapeutic strategies to decrease dicarbonyl compounds may be beneficial, such as dicarbonyl scavengers, glutathione repleting agents, and high-dose thiamine therapy.

Hepatitis B virus infection in isolated Afro-Brazilian communities

The prevalence and genotypes of hepatitis B virus (HBV) have distinct geographical distribution. In Brazil, some African-descendants have been maintained as small isolated communities since the slavery period. In this study, HBV infection among these communities of African origin was examined. Individuals (1,058) living in 12 communities were interviewed and serum samples screened for the presence of HBV markers. HBsAg-positive sera were tested for HBV DNA by PCR and positive samples were genotyped by restriction fragment length polymorphism (RFLP). The overall prevalence of HBV infection was 19.8% (95% CI: 17.5-22.3), ranging from 5.5% to 42.4%, depending on the communities studied. Multivariate analysis of risk factors showed that increasing age, family history of hepatitis, and sexual activity were associated significantly with this infection. HBsAg was detected in 23/1,058 (2.2%) individuals. HBV DNA was present in 2/2 of HBeAg-positive serum samples and in 18/21 (85.7%) anti-HBe-positive samples. All HBV isolates belonged to genotype A, subtype Aa. Three RFLP patterns were identified: AI (17 isolates), AIV (1 isolate), and AVI (2 isolates). These findings suggest a common introduction of HBV during the slave trade from Africa to Brazil.

Risk of hepatitis B exacerbation is low after transcatheter arterial chemoembolization therapy for patients with HBV-related hepatocellular carcinoma: report of a prospective study

OBJECTIVES

Systemic chemotherapy may lead to immune suppression and possible reactivation of hepatitis B virus (HBV), suggesting prophylactic antiviral therapy in cancer patients with HBV. Transcatheter arterial chemoembolization (TACE) for hepatocellular carcinoma (HCC) is not a systemic chemotherapy, but has been partially associated with HBV reactivation. The aim of this study was to evaluate whether TACE aggravates HBV hepatitis in patients with HBV-related HCC.

METHODS

Eighty-nine patients with HBV-related HCC were studied prospectively. Patients treated with TACE were enrolled in the case group (n = 69), and patients in follow-up or awaiting treatment were enrolled in the control group (n = 20). TACE was performed with doxorubicin (20-60 mg) and lipiodol (2-20 mL).

RESULTS

Three (4.3%) patients in the TACE group and 2 (10%) patients in the control group showed HBV reactivation (p= 0.334). A twofold or more increase in serum HBV DNA was detected in 21 (30.4%) patients in the TACE group and 4 (20%) patients in the control group (p= 0.361). Exacerbation of viral hepatitis B was found in 4 (5.8%) patients in the TACE group and no patients in the control group, but the difference between the two rates was not statistically significant (p= 0.271). Three of the four reactivated patients showed spontaneous recovery within 1 month, and one showed tumor-progression-related exacerbation.

CONCLUSIONS

One session of TACE using doxorubicin and lipiodol does not significantly aggravate HBV hepatitis in patients with HBV-related HCC.

Hepatitis A and B Booster Recommendations: Implications for Travelers

Hepatitis A and B are serious vaccine-preventable diseases with a predominantly overlapping epidemiological distribution. Travelers, a term encompassing a range of individuals, are at risk of contracting these diseases if they are unvaccinated. Although the benefits of the primary vaccination course of hepatitis A and B vaccines are clear, the administration of hepatitis A and B boosters varies worldwide. Recommendations on the need for booster vaccinations have recently been published, and the implications of these recommendations for travelers are discussed in this review. Until a greater understanding is reached on the immunogenicity of hepatitis A and B vaccines in certain special groups (e.g., immunocompromised persons), there will be a need to monitor antibody levels to assess whether booster vaccinations are required. However, for the majority of immunocompetent travelers, the full primary vaccination course will provide protection from both hepatitis A and B infection in the long term, without the need for boosters.

Induction of anti-proliferative mechanisms in hepatitis B virus producing cells

BACKGROUND/AIMS

Hepatitis B virus (HBV) preferentially replicates in quiescent cells. It was analyzed whether HBV affects cell cycle control.

METHODS

The amount of EGF-receptor (EGFR) and the binding capacity for 125I-EGF was determined. Expression of mdm2 and p21 and relevance of p53 for it were analyzed by reporter gene assays and western blotting. Cyclin A/E associated cdk2 activities were determined by immunocomplex assays. Cell proliferation was quantified by measurement of BrdU incorporation.

RESULTS

In HBV producing cells a significant reduction of EGFR expression, diminished 125I-EGF-binding capacity and insensitivity to EGF-stimulation were observed as compared to the control. Moreover, c-Raf-1-dependent induction of mdm2-P2 and p21cip1/waf1-promoter and elevated amounts of the respective proteins were observed in HBV producing cells. Whereas activation of mdm2-P2-promoter requires p53, activation of p21cip1/waf1-promoter is mediated partially by a p53-independent process. Induction of p21cip1/waf1 is reflected by a reduction of cyclin A associated cdk2 activity and an increase of cyclin E associated cdk2 activity. In accordance with this proliferation rate of HBV-producing hepatocytes is reduced as compared to control cells.

CONCLUSIONS

These results describe novel cell-cycle inhibitory functions of HBV that correlate well with the general concept of enhanced HBV replication in quiescent cells.

Travel-related hepatitis B: risk factors and prevention using an accelerated vaccination schedule

Rates of global travel and tourism are increasing dramatically, especially to regions with medium or high endemicity for hepatitis A and B, such as Asia, Africa, Latin America, and the Middle East. International travelers to these areas should be protected against both hepatitis A and B, regardless of their anticipated length of stay. However, many travelers depart within weeks of planning their trip (too late to complete the accelerated 0-, 1-, 2-month regimen for hepatitis B), and a majority of those traveling depart without being vaccinated. Although extended-stay travelers are at high risk for hepatitis B, short-stay travelers also are at risk. The most commonly encountered risk factors for travel-related hepatitis B are casual sexual activity with a new partner, medical and dental care abroad, and in the expatriate community, adoption of children who are hepatitis B carriers. Although efficacy studies of accelerated schedules for hepatitis B immunization have not been conducted, the results of immunogenicity studies in healthy volunteers who received an accelerated, 3-dose regimen on a 0-,7-, and 21-day schedule suggest that excellent, rapid, and long-term protection will be conferred. More data are needed to assess the efficacy of accelerated schedules in persons aged >40 years and to determine whether a fourth dose of hepatitis B vaccine is needed in all age groups.

Real-time PCR quantitation of hepatitis B virus DNA using automated sample preparation and murine cytomegalovirus internal control

Quantitation of circulating hepatitis B virus (HBV) DNA is important for monitoring disease progression and for assessing the response to antiviral therapy. Several commercial and 'in house' assays for HBV DNA quantitation have been described but many of these have limitations of relatively low sensitivity and limited dynamic range. This study describes the development and evaluation of a FRET-based real-time PCR assay designed to overcome these limitations and to provide accurate quantitation of DNA from all eight genotypes of HBV (A-H). The assay employs a fully automated nucleic acid extraction system permitting high-sample throughput with minimal 'hands-on' time and incorporates a murine cytomegalovirus (mCMV) internal control to prevent false negative results and under-reporting due to unrecognised problems with viral lysis, DNA purification or PCR amplification. Sensitivity, assessed by Probit analysis at the 95% detection level, was 24.4 IU/ml, associated with an extremely wide dynamic range (approximately 9 log10). Coefficients of variation were low for both intra-assay and inter-assay variability (CV%, 7-11%) and quantitative data correlated well (R2 = 0.97) with the Digene hybrid capture assay. This assay provides an ideal system for therapeutic monitoring and for studying the relationship between HBV viral load and stage of disease.

Intrafamilial spread of hepatitis B virus infection in Greece

OBJECTIVE

No study has investigated the intrafamilial spread of hepatitis B virus (HBV) in Greece. We conducted a 9-year prospective study to determine the rate of HBV spread in family members when a member is identified as an HBV carrier, the possible routes and risk factors for transmission of HBV and the family members with the highest risk of infection according to kinship degrees.

METHODS

A total of 387 family members of 166 hepatitis B surface antigen (HBsAg) carriers were investigated for the detection of HBV infection markers using standard enzyme immunoassays; 6.696 blood donors from the same area were used as controls.

RESULTS

Serological markers of past or current HBV infection were detected significantly more frequently among family members of HBsAg carriers (23.2 and 15.8%, respectively) compared with blood donors (14.1 and 0.85%, respectively). The prevalence of the above markers was higher among siblings, husbands and parents of the carriers. Offspring of the female index cases had higher rates of current or past infection. HBV infection markers were significantly increased in family members who reported common use of syringes (P<0.001), birth in rural areas (P<0.001) and a low level of education (P<0.001).

CONCLUSIONS

We demonstrated a high risk of HBV transmission among family members of HBsAg carriers, which was associated with special risk factors for contracting HBV. Our findings indicate the need for strict adherence to the universal guidelines of vaccination against HBV and also the need for an immediate investigation of other potentially infected relatives among family members of HBsAg carriers.

Efficient inhibition of hepatitis B virus replication by hammerhead ribozymes delivered by hepatitis delta virus

Although it has been suggested that hepatitis delta virus (HDV) can be used as a vector to deliver biologically active RNAs into hepatocytes, modified HDV as a specific transporting and replicating vector in anti-viral research has not been investigated. In this study, we focused on the development of HDV as a replicative vector to deliver hammerhead ribozyme into hepatocytes and the study of the roles of delivered hammerhead ribozyme on the replication of hepatitis B virus (HBV). To investigate the effects of ribozyme delivered by HDV on HBV replication, we designed two hammerhead ribozymes that specifically target the hepatitis B virus genome. These two ribozymes were then inserted into the genome of hepatitis delta virus. Results showed that transfection of cells with tandem modified HDV cDNA resulted in the production of monomer form of sense and anti-sense genomic RNA indicating the recombinant HDV-ribozyme could replicate effectively. Our data also indicated that ribozymes delivered by the modified HDV had higher level of inhibition activity against HBV replication than that of ribozyme alone. This system provides a new approach for the study of mechanisms of HBV replication as well as for the potential treatment of HBV infection.

Combination of small interfering RNAs mediates greater inhibition of human hepatitis B virus replication and antigen expression

OBJECTIVES

To evaluate the inhibitory effect mediated by combination of small interfering RNAs (siRNAs) targeting different sites of hepatitis B virus (HBV) transcripts on the viral replication and antigen expression in vitro.

METHODS

(1) Seven siRNAs targeting surface (S), polymerase (P) or precore (PreC) region of HBV genome were designed and chemically synthesized. (2) HBV-producing HepG2.2.15 cells were treated with or without siRNAs for 72 h. (3) HBsAg and HBeAg in the cell culture medium were detected by enzyme-linked immunoadsorbent assay. (4) Intracellular viral DNA was quantified by real-time PCR (Polymerase Chain Reaction). (5) HBV viral mRNA was reverse transcribed and quantified by real-time PCR. (6) The change of cell cycle and apoptosis was determined by flow cytometry.

RESULTS

Our data demonstrated that synthetic small interfering RNAs (siRNAs) targeting S and PreC gene could efficiently and specifically inhibit HBV replication and antigen expression. The expression of HBsAg and HBeAg and the replication of HBV could be specifically inhibited in a dose-dependent manner by siRNAs. Furthermore, our results showed that the combination of siRNAs targeting various regions could inhibit HBV replication and antigen expression in a more efficient way than the use of single siRNA at the same final concentration. No apoptotic change was observed in the cell after siRNA treatment.

CONCLUSION

Our results demonstrated that siRNAs exerted robust and specific inhibition on HBV replication and antigen expression in a cell culture system and combination of siRNAs targeting different regions exhibited more potency.

Mutations outside the YMDD motif in the P protein can also cause DHBV resistant to Lamivudine

AIM: To observe the Lamivudine resistance character of a DHBV strain in vitro and in vivo, and to analyze if the Lamivudine resistance character is caused by gene mutation or by abnormity of the Lamivudine metabolism.

METHODS: Congenitally DHBV-negative Guangdong brown ducks and duck embryo liver cells were respectively taken as animal and cell model. The Lamivudine-susceptive DHBV and Lamivudine-resistant DHBV (LRDHBV) were infected and Lamivudine was administrated according to the divided groups. The changes of DHBV quantity in the animal and cell model were tested. Three Lamivudine-resistant and two Lamivudine-susceptive DHBV complete genomes were successfully amplified, sequenced and then submitted to GenBank. All the DHBV complete sequences in the GenBank at present were taken to align with the three LRDHBV to analyze the mutational points related to the Lamivudine-resistant mutation.

RESULTS: Both the animal and cell model showed that the large and the small dosage Lamivudine have no significant inhibitory effect on the LRDHBV. Five sequences of DHBV complete genomes were successfully cloned. The GenBank accession numbers of the three sequences of LRDHBV are AY521226, AY521227, and AY433937. The two strains of Lamivudine-susceptive DHBV are AY392760 and AY536371. The correlated mutational points are KorR86Q and AorE591T in the P protein.

CONCLUSION: The Lamivudine resistance character of this DHBV strain is caused by genome mutation; the related mutational points are KorR86Q and AorE591T and have no relations with the YMDD motif mutation.

Chronic Hepatitis B and Viral Genotype: The Clinical Significance of Determining HBV Genotypes

The global health challenge posed by the hepatitis B virus (HBV) centres around the widespread distribution and the serious complications as a result of persistent infection with the virus. As with other chronic diseases mediated by pathogens such as human immunodeficiency virus (HIV) and hepatitis C virus (HCV), clinicians are searching for epidemiological, pathological and viral characteristics of HBV infection that may lead to more effective management of patients with chronic infection. Unlike HCV, the role of HBV genotype in disease progression, severity, response to therapy and drug resistance is still under investigation and just beginning to be clarified. This review examines the potential role of HBV genotype determination in the clinic with emphasis on how this genetic information may used to provide effective management for the treatment of patients with chronic hepatitis B.

Prevalence of hepatitis B surface antigen in vaccinated children and controls in rural Nigeria

OBJECTIVE

To determine the prevalence of hepatitis B surface antigen (HBsAg) amongst vaccinated children and controls aged 1-4 years in a rural community in mid-western Nigeria.

METHODS

The vaccinated children had received at least three doses of hepatitis B vaccine. The vaccines included recombinant hepatitis B vaccine at birth and a combined diphtheria, tetanus, pertussis (whole cell) plus hepatitis B (DTPw-HBV) vaccine. HBsAg was determined by a rapid immunoassay method based on the immunochromatographic sandwich principle. Two hundred and twenty-three children and 219 controls were recruited into the study.

RESULTS

The prevalence of HBsAg was significantly lower in the vaccinated group (1.3%) than in the control group (4.6%, p=0.04). The prevalence rates were significantly higher in males (p=0.02) and two-year birth cohort (p=0.01). The controls were estimated to be at a six-fold higher risk of being positive for the surface antigen than the vaccinated children. The vaccine effectiveness was estimated to be approximately 80%.

CONCLUSION

These results confirm that hepatitis B vaccine protects against hepatitis B surface antigen carriage and confirm immunogenicity of the combined DTPw-HBV vaccine.

Pregnant women as a sentinel population to target and implement hepatitis B virus (HBV) vaccine coverage: a three-year survey in Palermo, Sicily

Hepatitis B virus (HBV) vaccine coverage was assessed using serologic patterns of infection (HBsAg, anti HBc) and vaccine-induced immunity (isolated anti HBs) among 3318 pregnant women attending the Obstetrical Unit of the University Hospital in Palermo who were screened over 3 years (2001-2003). Three thousand and eight of them (90.6%) were born in Sicily, whereas 310 (9.4%) were immigrants from non-EU countries. The overall prevalence of HBsAg was 1.1%, and it was significantly higher among immigrant than indigenous women (4.2% versus 0.8%; OR 5.26; p < 0.0001). Serologic evidence of past HBV infection (anti HBc) also was significantly higher in immigrants than in Sicilian women (24.5% versus 5.2%, respectively). Women aged 17-21 in our study were in cohorts that had been targeted since 1991 for mandatory HBV vaccination at age 12. In this targeted age group, 74.2% of the Sicilian women had isolated anti HBs, compared to only 15.0% among immigrants. The results suggest the need to improve HBV immunization of Sicilian adolescents and especially to implement active surveillance and to launch an HBV immunization programme that targets immigrants to Sicily.

Immunogenicity and reactogenicity of a novel vaccine for human papillomavirus 16: a 2-year randomized controlled clinical trial

OBJECTIVE

To evaluate the immunogenicity, reactogenicity, and tolerability of a prototype human papillomavirus (HPV) 16 viruslike particle (VLP) vaccine directed against the L1 capsid protein.

SUBJECTS AND METHODS

We enrolled healthy nonpregnant women aged 18 to 26 years into a 2-year, double-blind, dose-ranging multicenter trial (October 12, 1998, to September 30, 2001). Subjects were assigned to study groups to receive a 3-dose regimen (day 0, month 2, and month 6) of 1 of 4 vaccine doses: 10 microg, 20 microg, 40 microg, or 80 microg or placebo. Serum anti-HPV 16 L1 antibody (sL1Ab) geometric mean titers (GMTs) were measured at day 0, at month 3, at month 7, and every 6 months for a total of 2 years using a radioimmunoassay. The primary immunogenicity analyses evaluated GMTs at month 7 in L1Ab-seronegative subjects at baseline. Vaccine tolerability was also assessed.

RESULTS

A total of 480 subjects were randomized to receive placebo (n=52) or 10 microg (n=112), 20 microg (n=105), 40 microg (n=104), or 80 microg (n=107) of HPV 16 L1 VLP vaccine. At baseline, 75% of subjects were L1Ab seronegative. All vaccine doses produced a statistically significant sL1Ab response vs placebo (P<.001). At the completion of the vaccination regimen, sL1Ab GMTs in baseline-seronegative subjects were 36- to 78-fold higher than the sL1Ab GMT at day 0 observed in subjects who had mounted an immune response to HPV 16 infection before enrollment. Serum L1Ab GMTs remained high throughout the 1.5-year postvaccination period. Postvaccination sL1Ab GMTs were 1.1- to 2.4-fold higher in women who had detectable sL1Ab levels at enrollment compared with those in baseline-seronegative subjects, particularly in the persistence phase. The vaccine was generally well tolerated with no statistically significant differences in injection site or systemic adverse experiences among treatment groups.

CONCLUSION

Immunization with this novel HPV 16 L1 VLP vaccine was well tolerated and produced an immunogenic response that persisted for at least 1.5 years after the final dose.

Entecavir for the treatment of chronic hepatitis B

Chronic infection with the hepatitis B virus remains a serious and life-threatening disease for approximately 5% of the world's population, despite the availability of effective vaccines. Although prognoses can be improved by chemotherapy, treatment options are limited and none has been consistently successful. Interferon-alpha, the longest established therapy, has limited efficacy, is slow-acting and frequently causes adverse effects. Newer drugs comprise of mainly nucleoside and nucleotide analogs. The two that are currently approved, lamivudine and adefovir dipivoxil, are well tolerated; both produce rapid and dramatic responses, but their effects may not be sustainable in the long-term due to the emergence of resistant virus. Development of resistance to lamivudine is approximately ten-times more frequent than development of resistance to adefovir dipivoxil (approximately 60 and 6%, respectively) during the first 3 years of therapy. Entecavir, a carbocyclic deoxyguanosine analog that is active against both lamivudine- and adefovir dipivoxil-resistant HBV, is in the vanguard of new antihepatitis B virus drugs that have progressed to Phase III clinical trials. It is the most potent antihepatitis B virus agent discovered to date.

How to diagnose and treat secondary forms of vasculitis

Vasculitis is considered to be secondary when it arises either in the context of a pre-existing connective tissue disease, as a result of direct infection with a limited range of organisms, especially viruses, or when it arises in response to exposure to a number of medications. Rheumatoid vasculitis is probably the most widely recognised form of secondary vasculitis, and in this article we review the incidence, clinical features and management of this condition. Infections may either trigger or cause some types of vasculitis. Drug therapy is a common cause of limited forms of vasculitis and may enhance our understanding of the mechanism of these diseases. The premature development of atherosclerosis in patients with existing connective tissue diseases or indeed primary vasculitis has been recognised for some time, and the underlying mechanisms are currently being studied. An appreciation of the complex and varied pathophysiology of secondary vasculitis may further our understanding of primary vasculitis.

Liver enzyme alteration: a guide for clinicians

Isolated alterations of biochemical markers of liver damage in a seemingly healthy patient can present a challenge for the clinician. In this review we provide a guide to interpreting alterations to liver enzyme levels. The functional anatomy of the liver and pathophysiology of liver enzyme alteration are briefly reviewed. Using a schematic approach that classifies enzyme alterations as predominantly hepatocellular or predominantly cholestatic, we review abnormal enzymatic activity within the 2 subgroups, the most common causes of enzyme alteration and suggested initial investigations.

Effect of alcohol on viral hepatitis and other forms of liver dysfunction

Alcohol is a known hepatotoxic agent, which may exacerbate liver injury caused by other agents. The wide prevalence of alcohol use and abuse in society makes it an important cofactor in many other liver diseases. Examples of liver diseases that are significantly influenced by ingestion of alcohol include chronic viral hepatitis, disorders of iron overload, and obesity-related liver disease.

Sexual transmission of hepatitis B

PURPOSE OF REVIEW

Hepatitis B virus infection is prevalent worldwide and is a significant cause of morbidity and mortality particularly in Asia. Adults chronically infected with hepatitis B virus remain a significant potential source of sexually transmitted hepatitis B. The purpose of this article is to review the recent literature relating to hepatitis B virus transmission with particular emphasis on sexual transmission and efforts to prevent spread.

RECENT FINDINGS

The introduction of hepatitis B virus vaccine and the implementation of universal childhood vaccination for hepatitis B in some countries have led to a dramatic reduction in the number of children with chronic hepatitis B. However, recent reports suggest that we are not as successful in preventing infection by sexual transmission. It is clear that sexual transmission of hepatitis B virus is still widespread and is a major problem in certain high-risk groups such as men who have sex with men, intravenous drug users, prisoners and sex workers. Significant problems remain with respect to education and vaccination within these groups.

SUMMARY

Hepatitis B virus remains a major health burden but it is preventable by education and vaccination. Greater resources are required to expand vaccination to the at-risk, sexually active adult populations if the World Health Organization ideal of hepatitis B virus eradication is to be realized and the burden of hepatitis B virus-related morbidity and mortality contained.

Epidemiology and Prevention of Hepatitis B Virus Infection

Hepatitis B is one of the most common infectious diseases globally. It has been estimated that there are 350 million chronic hepatitis B virus (HBV) carriers worldwide. The prevalence of chronic HBV infection varies geographically, from high (>8%), intermediate (2-7%) to low (<2%) prevalence. HBeAg-negative chronic hepatitis B (e-CHB) and occult HBV infection are two special clinical entities, and the prevalence and clinical implications remain to be explored. The predominant routes of transmission vary according to the endemicity of the HBV infection. In areas with high HBV endemicity, perinatal transmission is the main route of transmission, whereas in areas with low HBV endemicity, sexual contact amongst high-risk adults is the predominant route. HBV has been classified into 7 genotypes, i.e. A to G, based on the divergence of entire genome sequence and HBV genotypes have distinct geographical distributions. Three main strategies have been approved to be effective in preventing HBV infection. They are behavior modification, passive immunoprophylaxis, and active immunization. The implement of mass HBV immunization program is recommended by the WHO since 1991, and has dramatically decreased the prevalence of HBV infection and HCC in many countries.

Screening of binding protein of hepatitis B virus pre-pre-s promoter by phage display technique

AIM: To screen the binding protein gene of hepatitis B virus pre-pre-s promoter using phage display technique.

METHODS: Taking HBV pre-pre-S promoter as a solidified selective molecule, the phage-human liver cDNA library was biopanned and the positive clones were selected. The positive plaques were amplified and then cloned into pGEM-Teasy vector. The selected positive plaques were analyzed using bioinformatics and DNA sequencing.

RESULTS: Twenty positive clones were obtained, which included 17 clones with known function and 3 with unknown function.

CONCLUSION: The binding protein genes of HBV pre-pre-s promoter can be obtained by phage display technique, which may be helpful for further study of the pathogenesis of HBV infection.

Is vaccine therapy the future in cancer prevention?

One vaccine designed to prevent cancer by preventing a precursor infection is already in common use, and at least one more is in the latter stages of clinical development. These vaccines are part of a new era of cancer immunoprophylaxis. Several further vaccines are in preclinical and clinical development, targeted at preventing cancer precursor infections, and these should add to our ability to prevent this common human disorder. However, vaccines to prevent cancers not triggered by infection are a more remote prospect, for a variety of reasons.