Four to 6 months of conventional interferon alpha (IFN-alpha) (5MU daily or 10MU three times weekly) resulted in HBeAg loss in approximately 33% of HBeAg positive patients (controls: 12%). Longer treatment duration improved HBeAg seroconversion. Children with chronic HBV infection and high ALT respond to IFN-a at similar rates. Good end-of-treatment (ET) biochemical and virological response were also achieved with IFN-alpha in HBeAg negative, HBV-DNA positive hepatitis patients. Sustained response (SR) however, was disappointing, but improved with longer duration of treatment: (10-15% SR with 4/6 months treatment: 30% SR with 24 months treatment). Weekly pegylated IFN-alpha2a (PegIFN-alpha2a) for 24 weeks gave a significantly higher HBeAg conversion rate (33%) than conventional IFN-alpha2a (25%). Fifty-two weeks of PegIFN-alpha2b gave a sustained HBeAg loss in 35% patients and HBeAg seroconversion in 29% patients. Similar results were obtained with 48 weeks of weekly PegIFN-alpha2a. PegIFN-alpha2a monotherapy was found to be superior to lamivudine monotherapy in affecting a 6-month SR (normal ALTs and HBV DNA < 20,000 copies/mL) in HBeAg negative/anti-HBe positive chronic hepatitis B patients. There is a tendency for IFN-a and lamivudine combination to result in better sustained response than lamivudine monotherapy. This tendency is also observed with PegIFN-a and lamivudine combination although the combination did not appear to be better than PegIFN-alpha monotherapy. IFN induced HBeAg seroconversion is durable, could increase over time and resulted in better overall survival and survival free of hepatic decompensation or hepatocellular cancer. The main advantage of IFN-a therapy is that a course of finite duration may achieve sustained off-therapy response in a proportion of both HBeAg positive and HBeAg negative chronic hepatitis B patients. However, IFN treatment is usually associated with side-effects, especially flu-like symptoms, fatigue, neutropenia, thrombocytopenia and depression. These are usually tolerable but may require dose modification and premature cessation of treatment (5%). Interferon therapy induced hepatitis flares may lead to decompensation in patients with cirrhosis and can be dangerous in patients with decompensated liver function despite dose reduction.
One hundred and ninety hepatitis B surface antigen positive (HBsAG+) sera were subtyped, belonging to : blood donors, hepatitis patients, patients and staff in a hemodialysis unit, all from Kuala Lumpur; Malaysian aborigines from three jungle locations in Peninsular Malaysia; and East Malaysians from Sarawak, East Malaysia; Three subtypes adr, adw and ayw were present in Malaysia in the following frequencies: 44%, 29%, and 27%, respectively; In Kuala Lumpur 87% had subdeterminant d and 13 per cent y, whereas in the deep jungle aborigines of Perak and Pahang, the y subdeterminant was present in 87% and the d in 13%. A similar pattern of preponderance of y prevailed in Sarawak, East Malaysia. In Kuala Lumpur the two main ethnic groups, Malays and Chinese, differed in subtype distribution, in that adr predominated in the Malays (61%), while the adw predominated in the Chinese (51%); Subtype distribution was not related to age or sex of carriers of the antigen, or to whether they had hepatitis, or asymptomatic antigenemia.
A systematic review was performed to estimate the duration of protection of Hepatitis-B vaccine after primary vaccination during infancy. The number of seropositive participants with anti-HBs antibody titer ≥ 10 mIU/ml and seronegative participants who had anti-HBs antibody titer ≤ 10 mIU/ml after booster dose was the main outcome criteria to find out the protection time of Hepatitis-B vaccine. Twelve studies were selected for systematic review. Overall, results from the meta-analysis have revealed that the risk of Anti-HBs Titer ≤ 10 mIU/ml reduced by 50%. Upon performing the sub-group analysis it was revealed that the overall risk of having Anti-HBs Titre ≤ 10 mIU/ml was reduced up to 62% among the subjects age 21-30 years (0.38 [0.34, 0.44]; I2 = 0.0%, p = 0.938). Furthermore, it was observed that the risk of having titre level less than 10 mIU/ml for plasma derived vaccines were to be 56% [0.44, CI 0.33-0.57, I2 90.9%, p = <0.001]. Vaccination in early infancy does not ensure protection against Hepatitis-B infection. There is a strong correlation between the duration of protection and time elapsed after primary immunization during infancy.
Bio-nanogate involves synthesized or natural molecules as a 'gate' towards bioreceptors and responds upon the presence of targeted analytes in nanoscale dimension. Development of bio-nanogate improves analyte selectivity and signal response across various types of biosensors. The versatility of PAMAM dendrimers to form conjugates with guest molecules, such as proteins can be utilized in forming a bio-nanogate. PAMAM interaction with peptide bioreceptor for antibody detection is of interest in this study. This study investigated the interaction of synthesized immunogenic 'a' determinant (aD) region of hepatitis B virus surface antigen (HBsAg) with PAMAM G4 and anti-HBsAg antibody, as a potential bio-nanogate for anti-HBsAg detection. The aD peptide fused with maltose binding protein (MBP), was confirmed with Western blotting. Nano-Differential Scanning Fluorimetry (nano-DSF) study revealed that the interaction of MBP-aD with anti-HBsAg indicated a higher thermal stability as compared to its interaction with PAMAM G4. Electrochemical impedance spectroscopy showed that a higher binding constant of MBP-aD interaction with anti-HBsAg (0.92 μM-1) was observed at maximum saturation, as compared with PAMAM G4 (0.07 μM-1). Thermodynamic parameters demonstrated that MBP-aD interacted with anti-HBsAg and PAMAM G4, through van der Waals and hydrogen bonding. These analyses suggest that the weak interaction of MBP-aD and PAMAM G4 may form a potential bio-nanogate. It is hypothesized that the presence of anti-HBsAg has a higher affinity towards MBP-aD which may displace PAMAM G4 in the anti-HBsAg detection system. This interaction study is crucial as an initial platform of using peptide-PAMAM as a bio-nanogate in an antibody detection system.
Dental employees in government institutions in a State in Peninsular Malaysia were screened for exposure to hepatitis B virus (HBV) in 1989. Almost all (96.8%) of the 217 employees responded. One quarter (24.8%) was positive for at least one serological markers to HBV; 2.4% had hepatitis B surface antigen (HBsAg) and 22.4% had anti-body to HBsAg (anti-HBs). The presence of HBsAg was unrelated to age, sex, ethnicity, geographical locality and occupations of the subjects. The prevalence of anti-HBs increased with age and was highest for ethnic Chinese (53.6%), followed by Indians (25%), compared to Malays (14.9%) (p less than 0.001) and were increased among dentists (53.1%) and assistant nurses (33.3%). The overall prevalence of HBsAg and anti-HBs were similar to the situation in the community. However, dentists and their chairside assistant nurses, with a higher proportion of Chinese, had higher anti-HBs prevalences compared with that of the general population.
The infectiousness with regard to HBV Infection of staff and patients in various units of the General Hospital, Kuala Lumpur
was assessed. It was found that all units, with the exception of the obstetric unit, were equally high risk areas. At least 50% of the patients in all these units had one or more of the markers. Among the medical staff, the anaesthetists had the highest
incidence of HBV markers (100%) while medical officers who had worked for three years or more were more likely to have to
have the HBV markers. The degree of infectiousness of the nurses In HDU and ICU/OT was found to be similar.
Due to their impaired immune system, patients with renal insufficiency have a suboptimal response to hepatitis B (HB) vaccination and frequent boosters are needed to maintain protection. GlaxoSmithKline Biologicals has developed a HB vaccine containing a new adjuvant system AS04 for use in this immunocompromised patient population.
A total of 250 hepatitis B surface antigen positive sera were screened for antibody to hepatitis B surface antigen. It was found that seven (3%) sera showed concurrently circulating surface antigen and surface antibody to hepatitis B virus. The level of antibody to surface antigen was not affected by HBeAg and most of the cases were found in chronic hepatitis B carriers.
The percentage of lymphocyte subsets from the peripheral blood of healthy adults and hepatitis B surface antigen (HBsAg) carriers were analyzed by flow cytometry. The five lymphocyte subsets studied were:- T (CD3) cells, B (CD19) cells, CD4 cells, CD8 cells, Natural Killer (CD3- CD16+/CD56+) cells (NK cells) and the CD4/CD8 ratio. The percentage (mean +/- SD) for the five lymphocyte subsets from the healthy adults were (67.5 +/- 8.5)%, (12.4 +/- 4.5)%, (35.5 +/- 7.8)%, (36.8 +/- 8.5)%, (17.9 +/- 8.1)% and 1.1 +/- 0.6, respectively. HBsAg carriers positive for HBV-DNA had a lower CD4/CD8 ratio than the healthy population (P = 0.030). The percentage of CD8 cells in HBsAg carriers increased significantly (r = 0.28; P = 0.019) with an increase in ALT levels but the values remained within normal range. The percentage of NK cells and CD4/CD8 ratio in HBsAg carriers positive for anti-HBe were higher than HBsAg carriers negative for anti-HBe (92% of which are HBeAg positive) (P = 0.045 and P = 0.035, respectively). The CD4/CD8 ratio in HBsAg carriers negative for anti-HBe (92% positive for HBeAg) was also lower than in the healthy population (P = 0.042). HBsAg carriers positive for HBV-DNA, HBeAg and raised ALT levels had a lower CD4/ CD8 ratio than did the healthy population. The lower ratio was due to an increase in the percentage of CD8 cells. This suggests an activated immune response triggered by the infection in an attempt to clear the virus. HBsAg carriers with normal ALT levels and who are negative for HBV-DNA may be in a state of tolerance.
Blood samples from 1,600 persons who sought immunisation against hepatitis B in private clinics in Singapore in 1988-1989 were screened for two viral markers. Of that total, 4.81% were positive for HBsAg and 17.31% had anti-HBs levels greater than 10 mIU/ml, indicating that about 22.12% of the general population would not benefit from immunisation. Preimmunisation screening will identify persons not requiring the hepatitis B vaccine and thus, avoid wastage. When immunisation has already been performed without screening, recall for post-immunisation screening should be considered in order to detect the infectious hepatitis B carriers. Data in this study indicates that at this point in time, it is important to immunise adolescents and adults, in addition to neonates and children.
The implementation of the Expanded Program of Immunization (EPI) in 1989 has dramatic impact on hepatitis B virus (HBV) infection in school children in Malaysia. A cross-sectional seroprevalence study of HBV infection in 190,077 school children aged 7-12 years from 1997 to 2003 showed a steady decline of HBV surface antigen (HBsAg) prevalence rate from 2.5% for children born in 1985 to 0.4% among school children born in 1996. The overall prevalence of HBsAg was 0.6%, 0.7% in males and 0.6% in females. Over 92.7% of school children had been vaccinated with HBV vaccine, in which 93.7% were vaccinated under the EPI and 6.3% on voluntary basis. The school children vaccinated under EPI had a 0.4% HBsAg carrier rate, which was significantly lower than school children vaccinated on a voluntary basis (HBsAg carrier rate 1.3%) and non-vaccinated school children (HBsAg carrier rate 2.7%), suggesting that HBV vaccination of infants was the most effective measure in preventing vertical transmission of HBV in the hyperendemic region.
The role of hepatitis virus infection in glucose homeostasis is uncertain. We examined the associations between hepatitis B virus (HBV) or hepatitis C virus (HCV) infection and the development of diabetes in a cohort (N = 439,708) of asymptomatic participants in health screening examinations. In cross-sectional analyses, the multivariable-adjusted odds ratio for prevalent diabetes comparing hepatitis B surface antigen (HBsAg) (+) to HBsAg (-) participants was 1.17 (95% CI 1.06-1.31; P = 0.003). The corresponding odds ratio comparing hepatitis C antibodies (HCV Ab) (+) to HCV Ab (-) participants was 1.43 (95% CI 1.01-2.02, P = 0.043). In prospective analyses, the multivariable-adjusted hazard ratio for incident diabetes comparing HBsAg (+) to HbsAg (-) participants was 1.23 (95% CI 1.08-1.41; P = 0.007). The number of incident cases of diabetes among HCV Ab (+) participants (10 cases) was too small to reliably estimate the prospective association between HCV infection and diabetes. In this large population at low risk of diabetes, HBV and HCV infections were associated with diabetes prevalence and HBV infection with the risk of incident diabetes. Our studies add evidence suggesting that diabetes is an additional metabolic complication of HBV and HCV infection.
Several strategies have been developed to reduce hepatitis B infections. These include antenatal screening, universal immunisation of newborns and immunoglobulin therapy for babies who are at risk. Antenatal screening for hepatitis B is not routinely performed, but all newborns in Malaysia are immunised against hepatitis B. We assessed the prevalence of hepatitis B and the factors associated with it among antenatal mothers in Ipoh. This information is useful in decision-making for future hepatitis B screening programmes for antenatal mothers, allowing for immunoglobulin therapies for newborns if their mother's hepatitis B virus (HBV) status is known.
The diagnosis of hepatitis B virus (HBV) and monitoring of the vaccination efficiency against HBV require real-time analysis. The presence of antibody against hepatitis B virus surface antigen (anti-HBsAg) as a result of HBV infection and/or immunization may indicate individual immune status towards HBV. This study investigated the ability of a bio-nanogate-based displacement immunosensing strategy in detecting anti-HBsAg antibody, via nonspecific-binding between polyamidoamine dendrimers encapsulated gold nanoparticles (PAMAM-Au) and the 'antigenic determinant' region (aD) of HBsAg. For this purpose, maltose binding protein harbouring the aD region (MBP-aD) was synthesized as a bioreceptor and immobilized on the screen-printed carbon electrode (SPCE). Following that, PAMAM-Au was deposited on MBP-aD, forming the 'gate' and was used as a monitoring agent. Under optimal conditions, the high specificity of anti-HBsAg antibody towards MBP-aD displaced PAMAM-Au causing the decrement of anodic peak in differential pulse voltammetry (DPV) analysis. The signal changes were proportionally related to the concentration of anti-HBsAg antibody, in a range of 1 - 1000 mIU/mL with a limit of detection (LOD) of 2.5 mIU/mL. The results also showed high specificity and selectivity of the immunosensor platform in detecting anti-HBsAg antibody both in spiked buffer and human serum samples.
"Parenteral" or "serum" hepatitis is known to have afflicted man for centuries. However, it was not until the mid-1960s that the causative agent of this infection, the hepatitis B virus, was discovered. Since then, the biology and the replication strategy of the virus, and the clinical features and the epidemiology of the hepatitis B infection have been determined. Knowledge about the virus and the infection it causes led to the development of firstly, a plasma-derived vaccine and later a recombinant vaccine for the prevention of the infection. Integration of the hepatitis B vaccine into newborn vaccination programmes on a worldwide basis represents a major step in the effort to eliminate this infectious disease and its complications. Laboratory tests are available for the diagnosis and monitoring of the disease. Therapies have been developed to halt the progress of the chronic infection in affected individuals. While these developments have resulted in a decrease of the frequency of infection in many countries, particularly those that have implemented universal immunization of newborns, the chronic infection remains a significant global problem. Worldwide, over 300 million individuals are infected and each year, an estimated 1 million persons die from chronic complications of the disease including hepatocellular carcinoma and hepatic failure. The therapies currently available result in elimination of the virus in only a relatively small proportion of subjects and carry with it serious side effects. Geopolitical, economic and other factors hinder the vision of elimination of the infection through immunization programmes. Nevertheless, work continues to clarify further the underlying pathological mechanism of the infection, the host and viral factors that promote elimination or persistence of the virus in the human host. It is hoped that such investigations will reveal viral targets for the design of newer and potentially more effective drugs to treat the infection.
Mutations in the hepatitis B virus (HBV) genome can potentially lead to vaccination failure, diagnostic escape, and disease progression. However, there are no reports on viral gene expression and large hepatitis B surface antigen (HBsAg) antigenicity alterations due to mutations in HBV isolated from a Bangladeshi population. Here, we sequenced the full genome of the HBV isolated from a clinically infected patient in Bangladesh. The open reading frames (ORFs) (P, S, C, and X) of the isolated HBV strain were successfully amplified and cloned into a mammalian expression vector. The HBV isolate was identified as genotype C (sub-genotype C2), serotype adr, and evolutionarily related to strains isolated in Indonesia, Malaysia, and China. Clinically significant mutations, such as preS1 C2964A, reverse transcriptase domain I91L, and small HBsAg N3S, were identified. The viral P, S, C, and X genes were expressed in HEK-293T and HepG2 cells by transient transfection with a native subcellular distribution pattern analyzed by immunofluorescence assay. Western blotting of large HBsAg using preS1 antibody showed no staining, and preS1 ELISA showed a significant reduction in reactivity due to amino acid mutations. This mutated preS1 sequence has been identified in several Asian countries. To our knowledge, this is the first report investigating changes in large HBsAg antigenicity due to preS1 mutations.
Malaysia is a medium endemic country for hepatitis B virus (HBV) infection but little is known about HBV strains circulating in Malaysian blood donors. Viral load, HBsAg concentrations and nested PCR products from 84 HBV surface antigen (HBsAg) positive samples were analysed in detail. Median viral load was 3050 IU/mL and median HBsAg 1150 IU/mL. Fifty-six full genome, 20 pre-S/S, 1 S gene and six basic core promoter/precore-only sequences were obtained. Genotypes B and C were present at a ratio of 2:1, and two genotype D samples were obtained, both from donors of Indian background. Phylogenetically, genotype B was more diverse with subgenotypes B2-5, B7 and B8 present, while most genotype C strains were from subgenotype C1. Genotypes B and C were equally frequent in ethnic Malays, but 80% of strains from Chinese were genotype B. HBsAg concentrations were higher in genotype C than in genotype B, in Chinese than Malays and in donors under the age of 30. HBV vaccine escape substitutions (P120S/T, I126N and G145G) were present in six strains. In the large surface protein, immuno-inactive regions were more mutated than CD8 epitopes and the major hydrophilic region. Strains of genotype B or from ethnic Malays had higher genetic diversity than strains of genotype C or from Chinese donors. Hence HBV strains circulating in Malaysia are phylogenetically diverse reflecting the ethnic mix of its population. Ethnic Malays carry lower HBsAg levels and higher genetic diversity of the surface antigen, possibly resulting in more effective immune control of the infection.