Current topics in hepatitis B

Prevalence of occult hepatitis B virus infection in Egypt: a systematic review with meta-analysis

BACKGROUND

Occult hepatitis B virus (HBV) infection (OBI) is a major public health problem. The clinical importance of OBI stems from the fact that it can be transmitted to healthy individuals at extremely low viral load levels. Additionally, immunosuppression has the potential to trigger viral replication, which can result in life-threatening liver decompensation. Despite several studies examining the prevalence of OBI, the pooled prevalence of OBI in Egypt remains unknown, particularly among blood donors and high-risk individuals, to whom intervention should be targeted.

METHODS

A comprehensive literature search of the following databases was conducted from inception to October 2022 using the following keywords: occult hepatitis B virus infection or occult HBV infection or OBI and Egypt in MEDLINE [PubMed], Scopus, Google Scholar, and Web of Science. The review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement. I-squared and Cochran's Q were used to measure the heterogeneity between the studies, and based on the random effects model, results were reported as proportions (%) with a 95% confidence interval (CI). Analyses of subgroup analyses were conducted based on the target population. Sensitivity analyses were conducted using the leave-one-out approach to test the robustness of the results.

RESULTS

A total of 50 studies with 62 estimations of OBI were included, 19 in patients who were HBsAg-negative and anti-HBc-positive and 43 in patients who were HBsAg-negative. The highest prevalence (41%) was among multi-transfused patients according to  studies that report occult hepatitis B virus prevalence in an HBsAg-negative population, while the pooled prevalence of OBI among patients on hemodialysis, patients with chronic hepatitis C infection, patients with hepatocellular carcinoma (HCC), and patients with liver cirrhosis was 17%, 10%, 24%, and 13%, respectively. On the other hand, among studies that report OBI prevalence in HBsAg-negative and anti-HBc-positive individuals, the pooled prevalence of OBI among blood donors, patients with chronic hepatitis C infection, and patients with HCC was 12%, 15%, and 31%, respectively. Also, the majority of studies examining the genetic background of OBI have found that genotype D is the most prevalent.

CONCLUSION

 This study highlights the high prevalence in OBI among blood donors and high-risk populations in Egypt. The implementation of HBV nucleic acid amplification testing (NAT) may increase the safety of blood transfusions by excluding all HBV DNA-positive donations. However, the cost-effectiveness of these tests should be investigated.

Seroprevalence of hepatitis B virus surface antigen (HBsAg) in Egypt (2000-2022): a systematic review with meta-analysis

BACKGROUND

Hepatitis B infection seriously threatens global public health, especially in developing nations. Despite several investigations on HBV incidence, the national pooled prevalence remains unknown, particularly in populations at-risk at whom interventions should be primarily aimed.

METHODS

A comprehensive literature search of the following databases: Medline [PubMed], Scopus, Google Scholar, and Web of Science was conducted following the PRISMA guidelines. I-squared and Cochran's Q were used to measure the heterogeneity between the studies. Publications that matched the following were included: Primary studies published in Egypt from 2000 to 2022 reported HBV prevalence based on HBsAg. We excluded any studies that were not performed on Egyptians or that were performed on patients suspected of acute viral hepatitis or studies focusing on occult hepatitis or vaccination evaluation studies, or national surveys.

RESULTS

The systematic review included 68 eligible studies reporting a total of 82 incidences of HBV infection based on hepatitis B surface antigen with a total sample size of 862,037. The pooled national prevalence among studies was estimated to be 3.67% [95% CI; 3: 4.39]. Children under 20 with a history of HBV vaccination during infancy had the lowest prevalence of 0.69%. The pooled prevalence of HBV infection among pregnant women, blood donors, and healthcare workers was 2.95%, 1.8%, and 1.1%, respectively. While patients with hemolytic anemia and hemodialysis patients, patients with malignancies, HCC patients, and chronic liver disease patients had the highest prevalences at 6.34%, 25.5%, 18.6%, and 34%, respectively. Studies reporting HBV prevalence in urban settings compared to rural settings revealed a similar HBV prevalence of 2.43% and 2.15%, respectively. Studies comparing HBV prevalence in males and females revealed a higher prevalence among males (3.75%) than females (2.2%).

CONCLUSION

In Egypt, hepatitis B infection is a significant public health issue. The blocking of mother-to-infant hepatitis B transmission, the scaling up of the scope of the existing vaccination program, and implementing new strategies, including screen-and-treat, may reduce the prevalence of the disease.

Demographics and Epidemiology of Hepatitis B in the State of Qatar: A Five-Year Surveillance-Based Incidence Study

Background: Expatriates represent >80% of Qatar’s population, mostly arriving from countries in Africa and Asia that are endemic with many diseases. This increases the risk for introducing new pathogens into the country and provides a platform for maintenance of endemic pathogen circulation. Here, we report on the incidence and epidemiological characteristics of hepatitis B in Qatar between 2010 and 2014. Methods: We performed a retrospective epidemiological data analysis using the data available at the surveillance system of the Ministry of Public Health (MOPH) in Qatar. Data were collected from distinctive public and private incorporates around the nation. Reported cases of hepatitis B patients represent those who met the stringent case definition as per World Health Organization (WHO) and Centers for Disease Control and Prevention (CDC) guidelines and eventually reported to MOPH. Results: The annual incidence rates of hepatitis B cases were 30.0, 34.2, 30.5, 39.4, and 19.8 per 100,000 population in 2010, 2011, 2012, 2013, and 2014, respectively. There was no specific trend or seasonality for the reported cases. The incidence rates were higher in females compared to males between 2010 and 2012, but similar in 2013 and 2014. The highest incidence rates were reported among individuals between 25 and 34 years of age. No cases were reported in children younger than five years in 2013 and 2014. Rates of hepatitis B cases declined dramatically in 2014, in both Qataris and non-Qataris, as compared to the previous years. Conclusion: Our results indicate a dramatic decline of hepatitis B cases in Qatar but mandate improved surveillance and vaccination efforts in expatriates in the nation.

Association of IL-10 and IL-10RA single nucleotide polymorphisms with the responsiveness to HBV vaccination in Chinese infants of HBsAg(+)/HBeAg(-) mothers: a nested case-control study

OBJECTIVES

To investigate the association of interleukin (IL)-10 and IL-10 receptor A (IL-10RA) single nucleotide polymorphisms with the responsiveness to hepatitis B virus (HBV) vaccination in newborns whose mothers were hepatitis B surface antigen (HBsAg)(+)/hepatitis B e antigen (HBeAg)(-).

DESIGN

Nested case-control study.

SETTING

Changchun, China.

PARTICIPANTS

713 infants from a Han Chinese population whose mothers were HBsAg(+)/HBeAg(-) and participated in the prevention of mother-to-child transmission of HBV at the First Hospital of Jilin University from July 2012 to July 2015 were included. Infants were excluded for HBsAg-positive; unstandardised vaccination process; inadequate blood samples; not Han Chinese and failed genotyping.

RESULTS

Infants with artificial feeding pattern were correlated with low responsiveness to HBV vaccination (p=0.009). The GG genotype of IL-10 rs3021094 was correlated with a higher risk of low responsiveness to HBV vaccination (OR 2.80, 95% CI 1.35 to 5.83). No haplotype was found to be correlated with responsiveness to HBV vaccination. No gene-gene interaction was found between IL-10 and IL-10RA.

CONCLUSIONS

Our study found that IL-10 gene variants were significantly associated with the immune response to the HBV vaccine. Identifying these high-risk infants who born to HBsAg(+)/HBeAg(-) mothers and low responses to hepatitis B vaccination will provide evidence for individualised prevention strategies.

Hepatitis B virus genotypes among chronic hepatitis B patients reporting at Korle-Bu teaching hospital, Accra, Ghana

Introduction

Knowledge of hepatitis B virus (HBV) genotype is an important predictive variable which might have an impact in management and treatment of patients with chronic hepatitis B infection. In Ghana very little information is available on hepatitis B genotypes. This study was conducted to determine the distribution of HBV genotypes circulating among chronic hepatitis B patients reporting at the Korle-Bu Teaching Hospital (KBTH), Accra, Ghana.

Methods

Blood samples (10 ml) were collected from 250 consenting patients. DNA was extracted and amplified using polymerase chain reaction technique. Restriction fragment length polymorphism (RFLP) was used for the detection of genotypes.

Results

Out of the 250 chronic hepatitis B patients who were HBsAg positive, 91 (36.4%) were males aged 29.8 ± 9.1 and 159 (63.6%) females aged 33± 12.1 years. HBV DNA was detected in 111 (44.4%) but only 58 (52%) of these were typeable. These were classified as genotype A, 8 (7.2%); genotype D, 3 (2.7%) and genotype E, 47 (42.3%). Our results did not show any association between the infecting genotype and age (X²= 0.923; p-value=0.623) or gender (X²= 0.283, p= 0.579).

Conclusion

Consistent with similar studies worldwide, the results suggest that genotypes A, D and E were the genotypes circulating among chronic hepatitis B patients who reported to the Korle-Bu Teaching Hospital with genotype E being the most predominant and therefore constitutes an important public health concern. We recommend further epidemiological studies to understand the implication of genotype E in terms of disease progression and treatment.

The expression of miR-125b-5p is increased in the serum of patients with chronic hepatitis B infection and inhibits the detection of hepatitis B virus surface antigen

MicroRNAs were first discovered as small endogenous RNA molecules and some viruses have been reported to interact with host miRNAs. By investigating miRNA expression in serum derived from HBV-infected patients, we have clarified the relationship between miRNA expression and chronic HBV infection. Additionally, we demonstrate the use of miRNAs as both novel biomarkers and new therapies against HBV. We included the sera of 20 patients with chronic HBV infection, sera of 20 patients with HCV infection and sera of 10 healthy controls in this study. The miRNA libraries were sequenced using a 32-mer single end sequence. The validation study of circulating miRNA in serum was conducted by qRT-PCR. The HBV genomic regions of genotype B and genotype C that were speculated to be targeted by miRNA were constructed using complementary oligonucleotides in the vectors. Reporter assays were performed 48 h after transfection. The expression levels of 21 miRNAs were found to be differentially expressed in the three groups. 10 miRNAs (hsa-miR-100-5p, miR-125b-5p, miR-193b-3p, miR-194-3p, miR-30a-3p, miR-30c-2-3p, miR-3591-5p, miR-4709-3p, miR-574-3p and miR-99a-5p) were found to be upregulated in CH-B by deep sequence analysis. The computer analysis showed that two regions of HBsAg are potential targets of miR-125b-5p and miR-30c-2-3p and that these miRNAs may downregulate the expression of HBV-S. The HBV genotype C segment speculated to be targeted by hsa-miR-125b-5p significantly decreased the expression of the reporter. This study indicated that expression of miR-125b-5p was related to the etiology of chronic hepatitis B infection and regulated the expression of HBsAg.

Changes in the prevalence of HBV infection in pregnant women in Turkey between 1995 and 2015: a 20-year evaluation

OBJECTIVE

To determine changes in hepatitis B virus (HBV) prevalence across three different time periods in pregnant women.

METHODS

This was a retrospective study of pregnant women attending four healthcare centres between January 1995 and May 2015. Data for serum hepatitis B surface antigen (HBsAg) and anti-HBs levels were collected from routine antenatal screening records. The 20-year study was divided into three periods: 1995-2001, 2002-2008 and 2009-2015. The results are presented by the women's age and gravidity as possible determinants of HBV infection.

RESULTS

7605 pregnant women (56.0% primigravidae) (mean age 23.4±4.8 years) were tested for markers of HBV infection. 3010 pregnant women were screened between 1995 and 2001, 2995 between 2002 and 2008, and 1600 between 2009 and 2015. The overall prevalence of HBsAg and anti-HBs positivity in the 7605 pregnant women was 1.5% (n=114) and 11.5% (n=877), respectively. Regarding temporal change in the prevalence of HBV markers, HBsAg decreased significantly from 2.6% to 0.8% (p<0.01), while anti-HBs increased significantly from 9.5% to 17.5% (p<0.01), between the first and last study periods. Multigravidae and older women had higher HBsAg and anti-HBs positivity compared to primigravidae.

CONCLUSIONS

The data suggest that the prevalence of HBsAg positivity is gradually decreasing among pregnant women, while the level of HBsAg antibody seropositivity is lower than expected. HBV carrier rate increases with increasing age and gravidity. In addition to the national HBV immunisation programme, the prevention of perinatal transmission should also be prioritised to decrease the HBV pool of infection.

Deltex1 Polymorphisms Are Associated with Hepatitis B Vaccination Non-Response in Southwest China

Background

Hepatitis B vaccination is the most important tool available for preventing hepatitis B virus (HBV) infection and reducing the prevalence of infection. However, epidemiological studies have demonstrated that morethan 5% of patients exhibit a non- or hypo-response to the HBV vaccine. Genetic variations associated with T cell immunity contribute to the immune response to HBV vaccination. The deltex 1 (DTX1) gene is involved in T cell anergy, which may also be associated with the immune response to the HBV vaccination.

Methods

We detected 10 single nucleotide polymorphisms (SNPs) in or around the DTX1 gene in 601 infants out of a population from Southwest China, including 299 high responders(HRs; HBsAb > 100 mIU/mL) and 302 non-responders (NRs; HBsAb < 10 mIU/mL). An additional validation study was performed, comprising 230 adult patients(135 HRs and 95 NRs) from Southwest China.

Results

This study found that the minor allele ‘G’ of rs2384077 (adjusted p = 2.63E^-04,) and the minor allele ‘C’ of rs10744794 (adjusted p = 3.69E^-04) in the first intron of the DTX1 gene were remarkably associated with the immune response to HBV vaccination in both infant and adult populations. Moreover, a subsequent analysis indicated that haplotypes (A-T, G-C) of the two SNPs were significantly associated with the immune response to HBV vaccination.

Conclusions

Two SNPs (rs2384077 and rs10744794) in an intron of DTX1 and the linkage disequilibrium (LD) block are significantly associated with the immune response to HBV vaccination. The functional element annotation of the LD block between the two SNPs contains four transcriptional regulatory elements. The results suggest that these two SNPs may be involved in the immune response to HBV vaccination.

Hepatitis B Virus Infection, MicroRNAs and Liver Disease

Hepatitis B virus (HBV) attacks the liver and can cause both acute as well as chronic liver diseases which might lead to liver cirrhosis and hepatocellular carcinoma. Regardless of the availability of a vaccine and numerous treatment options, HBV is a major cause of morbidity and mortality across the world. Recently, microRNAs (miRNAs) have emerged as important modulators of gene function. Studies on the role of miRNA in the regulation of hepatitis B virus gene expression have been the focus of modern antiviral research. miRNAs can regulate viral replication and pathogenesis in a number of different ways, which includefacilitation, direct or indirect inhibition, activation of immune response, epigenetic modulation, etc. Nevertheless, these mechanisms can appropriately be used with a diagnosticand/or therapeutic approach. The present review is an attempt to classify specific miRNAs that are reported to be associated with various aspects of hepatitis B biology, in order to precisely present the participation of individual miRNAs in multiple aspects relating to HBV.

Molecular mechanisms underlying HBsAg negativity in occult HBV infection

Although genomic detection is considered the gold standard test on HBV infection identification, the HBsAg investigation is still the most frequent clinical laboratory request to diagnose HBV infection in activity. However, the non-detection of HBsAg in the bloodstream of chronic or acutely infected individuals has been a phenomenon often observed in clinical practice, despite the high sensitivity and specificity of screening assays standardized commercially and adopted in routine. The expansion of knowledge about the hepatitis B virus biology (replication/life cycle, genetic variability/mutability/heterogeneity), their biochemical and immunological properties (antigenicity and immunogenicity), in turn, has allowed to elucidate some mechanisms that may explain the occurrence of this phenomenon. Therefore, the negativity for HBsAg during the acute or chronic infection course may become a fragile or at least questionable result. This manuscript discusses some mechanisms that could explain the negativity for HBsAg in a serological profile of individuals with HBV infection in activity, or factors that could compromise its detection in the bloodstream during HBV infection.

A MAVS/TICAM-1-independent interferon-inducing pathway contributes to regulation of hepatitis B virus replication in the mouse hydrodynamic injection model

Toll-like receptors (TLRs) and cytoplasmic RNA sensors have been reported to be involved in the regulation of hepatitis B virus (HBV) replication, but remain controversial due to the lack of a natural infectious model. Our current study sets out to characterize aspects of the role of the innate immune system in eliminating HBV using hydrodynamic-based injection of HBV replicative plasmid and knockout mice deficient in specific pathways of the innate system. The evidence indicated that viral replication was not affected by MAVS or TICAM-1 knockout, but absence of interferon regulatory factor 3 (IRF-3) and IRF-7 transcription factors, as well as the interferon (IFN) receptor, had an adverse effect on the inhibition of HBV replication, demonstrating the dispensability of MAVS and TICAM-1 pathways in the early innate response against HBV. Myd88(-/-) mice did not have a significant increase in the initial viremia, but substantial viral antigen persisted in the mice sera, a response similar to Rag2(-/-) mice, suggesting that the MyD88-dependent pathway participated in evoking an adaptive immune response against the clearance of intrahepatic HBV. Taken together, we show that the RNA-sensing pathways do not participate in the regulation of HBV replication in a mouse model; meanwhile MyD88 is implicated in the HBV clearance.

Development of probiotic-based immunoparticles for pulmonary immunization against Hepatitis B

OBJECTIVES

The present study was oriented towards the development of pulmonary vaccine for Hepatitis B using probiotic biomass as an adjuvant.

METHODS

The antigen was spray dried in presence of heat treated, formalin treated and live probiotic biomass.

KEY FINDINGS

The results indicated that the biomass itself without any additional cryoprotectant is capable of protecting the structural integrity of the antigen. We were able to retain more than 80% of the antigenicity. The scanning electron microscopic images indicated that the formulation bearing live probiotic biomass have spherical size, while the formulations with heat and formalin treated biomass shows irregular shaped particles. The developed formulations were further evaluated for in-vivo immune response. Immunoglobulin G (IgG) titre results were found to be comparable with marketed (aluminium adsorbed) formulations while significantly higher secretory immunoglobulin A titre showed better mucosal immune response than marketed formulation.

CONCLUSION

Therefore, the probiotic biomass can be utilized as a potential cryoprotectant as well as a potent immunomodulator.

FAS and FASL gene polymorphisms are not associated with hepatitis B virus infection based on a case-control study in a Brazilian population

Objective. This study investigated the association of the single nucleotide polymorphisms (SNPs) in the FAS and FASL genes with the outcome of hepatitis B virus (HBV) infection. Methods. Blood samples were collected from 116 HBV-infected patients at the Hospital of the Santa Casa de Misericordia Foundation (Belém, PA, Brazil). Seronegative individuals were used as controls. DNA samples were extracted from the leukocytes and assayed using the polymerase chain reaction (PCR) followed by RFLP analysis with restriction endonucleases. Results. The frequencies of the mutant genotypes for -670FAS (GG), Ivs2nt-124FASL (GG), Ivs3nt-169FASL (ΔT/ΔT), and -844FASL (TT) were higher in the HBV patients, and the FAS-1377AA genotype was more frequent in the control group; however, the differences between the allele and genotype frequencies were not statistically significant. When the HBV patient population was divided into two groups (inactive carriers and active chronic hepatitis patients), the mutant genotypes were found to be more prevalent in the active chronic hepatitis group with respect to the FAS gene polymorphisms; however, this difference was not statistically significant. Conclusions. The results suggest that the polymorphisms in FAS and FASL genes are not associated with HBV infection or even with the natural history of the infection in the Brazilian Amazon region.

MicroRNAs may solve the mystery of chronic hepatitis B virus infection

Hepatitis B virus (HBV) infection is a global public health problem that causes persistent liver diseases such as chronic hepatitis, cirrhosis, and hepatocellular carcinoma. A large amount of people die annually from HBV infection. However, the pathogenesises of the HBV-related diseases are ill defined and the therapeutic strategies for the diseases are less than optimum. The recently discovered microRNAs (miRNAs) are tiny noncoding RNAs that regulate gene expression primarily at the post-transcriptional level by binding to mRNAs. miRNAs contribute to a variety of physiological and pathological processes. A number of miRNAs have been found to play a pivotal role in the host-virus interaction including host-HBV interaction. Numerous studies have indicated that HBV infection could change the cellular miRNA expression patterns and different stages of HBV associated disease have displayed distinctive miRNA profiles. Furthermore, the differential expressed miRNAs have been found involved in the progression of HBV-related diseases, for instance some miRNAs are involved in liver tumorigenesis and tumor metastasis. Studies have also shown that the circulating miRNA in serum or plasma might be a very useful biomarker for the diagnosis and prognosis of HBV-related diseases. In addition, miRNA-based therapy strategies have attracted increasing attention, indicating a promising future in the treatment of HBV-related diseases.

Development of a highly sensitive bioluminescent enzyme immunoassay for hepatitis B virus surface antigen capable of detecting divergent mutants

Hepatitis B virus (HBV) infections are sometimes overlooked when using commercial kits to measure hepatitis B virus surface antigen (HBsAg) due to their low sensitivities and reactivities to mutant strains of various genotypes. We developed an ultrasensitive bioluminescent enzyme immunoassay (BLEIA) for HBsAg using firefly luciferase, which is adaptable to a variety of HBsAg mutants, by combining four monoclonal antibodies with a polyclonal antibody against HBsAg. The measurement of seroconversion panels showed trace amounts of HBsAg during the early infection phase by the BLEIA because of its high sensitivity of 5 mIU/ml. The BLEIA detected HBsAg as early as did PCR in five of seven series and from 2.1 to 9.4 days earlier than commercial immunoassay methods. During the late infection phase, the BLEIA successfully detected HBsAg even 40 days after the disappearance of HBV DNA and the emergence of antibodies against HBsAg. The HBsAg BLEIA successfully detected all 13 recombinant HBsAg and 45 types of HBsAg mutants with various mutations within amino acids 90 to 164 in the S gene product. Some specimens had higher values determined by the BLEIA than those by a commercial chemiluminescent immunoassay; this suggests that such discrepancies were caused by the dissociation of preS1/preS2 peptides from the particle surface. With its highly sensitive detection of low-titer HBsAg, including various mutants, the HBsAg BLEIA is considered to be useful for the early diagnosis and prevention of HBV infection because of the shorter window of infection prior to detection, which facilitates early prediction of recurrence in HBV-infected individuals.

Chronic HBV infection among pregnant women and their infants in Shenyang, China

Background

The main transmission route of the hepatitis B virus (HBV) is mother to child transmission and contributes significantly to chronic HBV infection. Even though immunoprophylaxis with hepatitis B immunoglobulin (HBIG) and hepatitis B vaccine is administrated to neonates whose mothers are hepatitis B surface antigen (HBsAg) positive, about 10% of the neonates suffer from HBV infection in their early life.

Objectives

To survey chronic HBV infection among pregnant women and their infants and analyze the reason for immunoprophylaxis failure.

Methods

Serum HBsAg was tested in all pregnant women. HBVDNA and other serum HBV markers including hepatitis B e antigen (HBeAg), hepatitis B core antibody (anti-HBc) and hepatitis B surface antibody (anti-HBs) were tested among HBsAg positive pregnant women. All infants whose mothers were HBsAg positive were vaccinated with a standard immunoprophylaxis. Serum HBV markers and HBVDNA were tested among these infants at 7 months of age. HBV genotypes were analyzed among the infants and pregnant women who were HBVDNA positive.

Results

The prevalence of HBsAg, anti-HBc and anti-HBs among 4,536 pregnant women was 5.49%, 29.65% and 58.55%, respectively. The prevalence of HBsAg, anti-HBc and anti-HBs among pregnant women older than 20 years of age was significantly different compared to pregnant women younger than 20 years of age (4.54, 5.69 and 0.61 times, prevalence older vs. younger, respectively. P<0.05, 0.01, 0.05, respectively). Among 249 HBsAg positive pregnant women, 167 (67.07%) were HBeAg positive, 204 (81.93%) were HBVDNA positive and only 37 (14.86%) had HBVDNA >10⁷ IU/ml. Among the infants whose mothers were HBsAg positive, 214 (85.94%) infants were anti-HBs positive. There were 12 (4.82%) infants who were HBsAg and HBVDNA positive, and all 12 of these infants mothers were HBeAg positive and had HBVDNA >10⁷ IU/ml. Genotypes B and C were present among 165 pregnant women and genotype C was present in 85 pregnant women. There were 12 infants who were HBsAg positive and had the same HBV genotypes as their mothers. There was a significant difference in genotypes between the pregnant women whose infants were infected with HBV compared to those without HBV infection (P < 0.05).

Conclusions

There was a significant decline in HBsAg prevalence among pregnant women and their infants in Shenyang. Genotype C might be a risk factor for mother to child transmission of HBV.

Atypical serological profiles in hepatitis B virus infection

During hepatitis B virus (HBV) infection, at least four antigen-antibody systems are observed: HBsAg and anti-HBs; preS antigen and anti-preS antibody; HBcAg and anti-HBc; and HBeAg and anti-HBe. Through the examination of these antigen-antibody systems, hepatitis B infection is diagnosed and the course of the disorder may be observed. Although the serologic findings that allow both the diagnosis of HBV infection as well as assessing of its clinical course are already well established, the dynamics of viral proteins expression and of the antibodies production may vary during the infection natural course. This causes the HBV infection to be occasionally associated with the presence of uncommon serological profiles, which could lead to doubts in the interpretation of results or suspicion of a serological result being incorrect. This paper is dedicated to the discussion of some of these profiles and their significance.

CD3Z genetic polymorphism in immune response to hepatitis B vaccination in two independent Chinese populations

Vaccination against hepatitis B virus is an effective and routine practice that can prevent infection. However, vaccine-induced immunity to hepatitis B varies among individuals. CD4⁺ T helper cells, which play an important role in both cellular and humoral immunity, are involved in the immune response elicited by vaccination. Polymorphisms in the genes involved in stimulating the activation and proliferation of CD4⁺ T helper cells may influence the immune response to hepatitis B vaccination. In the first stage of the present study, a total of 111 single nucleotide polymorphisms (SNPs) in 17 genes were analyzed, using the iPLEX MassARRAY system, among 214 high responders and 107 low responders to hepatitis B vaccination. Three SNPs (rs12133337 and rs10918706 in CD3Z, rs10912564 in OX40L) were associated significantly with the immune response to hepatitis B vaccination (P = 0.008, 0.041, and 0.019, respectively). The three SNPs were analyzed further with the TaqMan-MGB or TaqMan-BHQ probe-based real-time polymerase chain reaction in another independent population, which included 1090 high responders and 636 low responders. The minor allele ‘C’ of rs12133337 continued to show an association with a lower response to hepatitis B vaccination (P = 0.033, odds radio = 1.28, 95% confidence interval = 1.01–1.61). Furthermore, in the stratified analysis for both the first and second populations, the association of the minor allele ‘C’ of rs12133337 with a lower response to hepatitis B vaccination was more prominent after individuals who were overweight or obese (body mass index ≥25 kg/m²) were excluded (1^st stage: P = 0.003, 2^nd stage: P = 0.002, P-combined = 9.47e-5). These findings suggest that the rs12133337 polymorphism in the CD3Z gene might affect the immune response to hepatitis B vaccination, and that a lower BMI might increase the contribution of the polymorphism to immunity to hepatitis B vaccination.

Low prevalence of hepatitis B virus pre-S deletion mutation in Indonesia

The molecular epidemiological study of hepatitis B virus (HBV) in Indonesia is still limited. This study was aimed to identify the prevalence of HBV pre-S deletion/insertion mutations, and to assess the association of pre-S deletion mutation with liver disease progression in Indonesia. Pre-S mutations were identified by direct sequencing. Of the 265 subjects, 32 samples (12.1%) harbored pre-S deletion/insertion mutations. The prevalence of those pre-S mutations was 2.7% (2/75), 12.9% (8/62), 16.7% (11/66), and 17.7% (11/62) in asymptomatic carrier, chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma groups, respectively. Statistical analysis showed significant difference among them (P = 0.024). In HBV genotype B (HBV/B), pre-S1, pre-S1/S2, and pre-S2 deletion mutations were detected respectively in 3 (17.6%), 4 (23.5%), and 9 (52.9%) of 17 samples. On the other hand, in HBV/C, 12 of 15 samples (80.0%) showed a pre-S2 deletion mutation, and only 2 samples (13.3%) demonstrated a pre-S1/S2 deletion mutation. These results suggest that in HBV/B deletion mutation tends to occur in pre-S1 or pre-S1/S2 region, while in HBV/C the deletion mutation usually occurs in the pre-S2 region. Analysis of complete genome of four viruses confirmed that 3 isolates were classified into HBV/B3, and 1 isolate was HBV/C1. However, SimPlot and BootScan analyses showed that isolate 08.10.002 was an intragenotypic recombinant between HBV/B3 and HBV/B4. As conclusion, the prevalence of HBV pre-S mutations was relatively low in Indonesian patients compared to those from Taiwan, Japan, and other Asian countries. There was a weak association between pre-S deletion mutation and progressive liver disease.

Association between polymorphisms of the cytokine and cytokine receptor genes and immune response to hepatitis B vaccination in a Chinese Han population

The immune response to hepatitis B vaccination varies among individuals. It has been reported that polymorphisms in cytokine and cytokine receptor genes are associated with these individual differences. The aim of the current study was to investigate the association between polymorphisms of the Th1/Th2 cytokine and cytokine receptor genes and the response to hepatitis B vaccination in a Chinese Han population. A total of 10 single nucleotide polymorphisms distributed in 6 genes (TNFRSF1A, IL12A, IL12B, IFNG, IL4, and IL10) were genotyped in 214 high-responders [hepatitis B surface antibody (anti-HBs) ≥1,000 mIU/ml] and 107 low-responders (anti-HBs: 10-99 mIU/ml). The minor CTCTAA allele of rs17860508 in the IL12B gene was associated with a low response to hepatitis B vaccination (P = 0.039, odds ratio = 1.41, 95% confidence interval = 1.00-1.99). In addition, a significant gene-gene interaction was found: the frequency of the combined genotypes IL12A rs2243115 TT and IL12B rs17860508 CTCTAA/CTCTAA was significantly higher in the low-response group than in the high-response group (P = 0.008, odds ratio = 2.19, 95% confidence interval = 1.23-3.93). These findings suggest that polymorphisms in the IL12A and IL12B genes might play an important role jointly in determining the response to hepatitis B vaccination.

Analysis of the full-length genomes of novel hepatitis B virus subgenotypes C11 and C12 in Papua, Indonesia

Two novel subgenotypes (C6 and D6) of hepatitis B virus (HBV) were identified recently in Papua, a multiethnic area of Indonesia. To characterize further the HBV strains in Papua, serum samples collected from 59 viremic subjects (44 males and 15 females; mean age: 30.0 ± 15.5 years) among indigenous inhabitants in Papua, were subjected to phylogenetic analysis of an 1.6-kb partial sequence. Forty-five samples (76%) had genotype C HBV (HBV/C) [C5 (n = 1), C6 (n = 40), and unclassifiable (n = 4)], while seven samples (12%) were HBV/D [D1 (n = 1) and D6 (n = 6)] and six samples (10%) were HBV/B [B2 (n = 1), B3 (n = 3), B7 (n = 1), and B8 (n = 1)]; the remaining sample possessed B3 and C6. An analysis of the full-length sequence of the four HBV/C isolates (NMB09122, NMB09124, NMB09075, and MRK89073) that were unclassifiable into any of the 10 known HBV/C subgenotypes (C1-C10) showed no significant evidence of recombination. Over the entire genome, the NMB09122 and NMB09124 isolates shared 99.8% identity and segregated into a cluster with a bootstrap value of 100%, differing from HBV/C1-HBV/C10 by 3.8-6.9% (mean, ≥4.0%), indicating that NMB09122 and NMB09124 can be classified into a novel subgenotype within genotype C (tentatively designated C11). The NMB09075 and MRK89073 isolates were 97.4% identical to each other and differed from known HBV/C isolates, including the C11 strains, by 4.0-7.2% (mean, ≥4.5%) over the entire genome, indicating that NMB09075 and MRK89703 can be classified into another novel HBV/C subgenotype (C12). The distribution of C11 and C12 seemed to be associated with particular language speakers in Papua.

Rapid detection of the hepatitis B virus YMDD mutant using AllGlo™ probes

BACKGROUND

The early detection of hepatitis B virus (HBV) mutants in clinical samples is important when monitoring chronic HBV patients with lamivudine-resistant mutations during lamivudine therapy.

METHODS

The AllGlo™ probes were designed to distinguish between wild-type (YMDD) and mutant (YVDD and YIDD) strains of HBV. The sensitivity and specificity of the assay were evaluated using a series of diluted mixtures of wild-type and mutant plasmids. This assay was compared with direct sequencing and the mutation-specific primer assay.

RESULTS

Each YMDD, YVDD, and YIDD probe only detected its corresponding plasmid. Moreover, the assay correctly identified negative samples from 40 non-HBV infected patients and 100 healthy controls. The detection limit of this assay was 50 copies/ml for YVDD and YIDD. The assay could detect the mutant strains when they were present at ≥10% within a mixed virus population. The assay was fully concordant with direct sequencing in 34 samples (56.7%) and partially concordant in 26 samples (43.3%), and detected more types of the HBV motif than direct sequencing.

CONCLUSIONS

AllGlo™ probe assay is a novel, sensitive and specific assay to detect lamivudine-related HBV mutants, therefore, may be useful for monitoring chronic HBV patients treated with lamivudine.

Immunization of guinea pigs with novel hepatitis B antigen as nanoparticle aggregate powders administered by the pulmonary route

Novel nanoparticle-aggregate formulations containing recombinant hepatitis B surface antigen (rHBsAg) were administered to the lungs of guinea pigs and antibodies generated to this antigen evaluated. Preparations of dry powders of: (a) rHBsAg encapsulated within poly(lactic-co-glycolic acid) (PLGA)/polyethylene glycol (PEG) nanoparticles (antigen nanoparticles, AgN(SD)), (b) rHBsAg in a physical mixture with blank PLGA/PEG nanoparticles (antigen nanoparticle admixture (AgNA(SD)), and (c) rHBsAg encapsulated in PLGA/PEG nanoparticles plus free rHBsAg (antigen nanoparticles and free antigen), were generated by spray drying with leucine. Control groups consisted of alum with adsorbed rHBsAg (AlumAg); reconstituted suspensions of spray-dried rHBsAg-loaded PLGA/PEG nanoparticles with leucine; and rHBsAg-loaded PLGA/PEG nanoparticles (AgN). Control preparations were administered by intramuscular injection; AgN was also spray instilled into the lungs. The IgG titers were measured in the serum for 24 weeks after the initial immunization; IgA titers were measured in the bronchio-alveolar lavage fluid. While the highest titer of serum IgG antibody was observed in guinea pigs immunized with AlumAg administered by the IM route, animals immunized with powder formulations via the pulmonary route exhibited high IgA titers. In addition, guinea pigs immunized with AgNA(SD) via the pulmonary route exhibited IgG titers above 1,000 mIU/ml in the serum (IgG titers above 10 mIU/ml is considered protective). Thus, the disadvantages observed with the existing hepatitis B vaccine administered by the parenteral route may be overcome by administering them as novel dry powders to the lungs. In addition, these powders have the advantage of eliciting a high mucosal immune response in the lungs without traditional adjuvants.

Occult hepatitis B virus infection and lamivudine-resistant mutations in isolates from renal patients undergoing hemodialysis

BACKGROUND AND AIMS

Patients undergoing hemodialysis are at risk of infection with both hepatitis B virus (HBV) and hepatitis C virus (HCV). Occult HBV infection is usually associated with low levels of HBV and is frequently detected in HCV-infected patients. The aims of the present study were to compare the prevalence of occult HBV infection among anti-HCV-positive and anti-HCV-negative patients undergoing hemodialysis, and characterize the molecular patterns of HBV isolates from patients with occult infection.

METHODS

Serum samples from 100 patients negative for hepatitis B surface antigen undergoing hemodialysis, half of whom were positive for anti-HCV antibodies, were tested for the presence of HBV-DNA using semi-nested polymerase chain reaction (PCR). PCR products of the S gene were directly sequenced.

RESULTS

HBV-DNA was detected in 15 samples. There were no significant differences in HCV status, sex, age, time of dialysis, alanine aminotransferase levels or HBV serological markers between patients with or without occult HBV infection, with the exception of antibody to hepatitis B core antigen (anti-HBc)-only serological marker (P = 0.003). All six HBV isolates that could be sequenced were of genotype A/subgenotype A1. Four of these six HBV isolates contained mutations associated with lamivudine resistance in the DNA polymerase (two with L180M/M204V and two with rt173V/180M/204V) and a specific substitution (Y100C) in the HBV small surface protein.

CONCLUSIONS

HBV isolates with the identified substitutions have the potential to spread silently by nosocomial transmission within the hemodialysis unit. These results have potential implications for the management of patients with occult HBV infection undergoing hemodialysis.

The underlying mechanisms for the 'anti-HBc alone' serological profile

The serological pattern, "anti-HBc alone", characterized by the presence of antibodies against the core antigen of hepatitis B virus (anti-HBc) as the only marker of hepatitis B, is not rare in a diagnostic setting. Depending on the prevalence of HBV infection and the patient group investigated, 1-31% of positive anti-HBc results are isolated positive findings. Anti-HBc alone is frequently observed in intravenous drug addicts, HIV-infected individuals, patients who are coinfected with HBV and hepatitis C virus, and pregnant women. However, it is not clear how this profile should be interpreted. Several studies have shown that anti-HBc alone is not only compatible with acute and resolved HBV infection but also with chronic infection. The reasons for the lack of HBsAg and anti-HBs in anti-HBc-alone individuals are not clear, but several mechanisms and possibilities have been suggested that could explain this phenomenon, some of which are delineated in this article.

Hepatitis B virus genotypes/subgenotypes in voluntary blood donors in Makassar, South Sulawesi, Indonesia

Background

Hepatitis B virus (HBV) genotype appears to show varying geographic distribution. Molecular epidemiological study of HBV in particular areas in Indonesia is still limited. This study was aimed to identify the prevalence of HBV genotype/subgenotype and mutations in basal core promoter (BCP) region in voluntary blood donors in Makassar, one of the biggest cities in east part of Indonesia.

A total of 214 hepatitis B surface antigen (HBsAg)-positive samples were enrolled in this study. HBV genotype/subgenotype was identified by genotype-specific PCR method or direct sequencing of pre-S region. Mutations in BCP were identified by direct sequencing of the corresponding region.

Results

HBV/B and HBV/C were detected in 61.21% and 25.23% of the samples, while mix of HBV/B and HBV/C was found in 12.62% of the samples. Based on pre-S region, among HBV/B and HBV/C, HBV/B3 (95.00%) and HBV/C1 (58.82%) were predominant. Interestingly, HBV/D was identified in two samples (22.165.07 and 22.252.07). Complete genome sequences of two HBV/D strains (22.165.07 and 22.252.07) demonstrated that both strains belong to HBV/D6, and the divergence between the two strains were 1.45%, while divergences of both 22.165.07 and 22.252.07 strains with reference strain (AM422939/France) were 2.67%. A1762T/G1764A mutation was observed in 1.96% and 5.36%, whereas T1753V mutation was found in 2.94% and 1.79% of HBV/B and HBV/C, respectively.

Conclusion

HBV/B and HBV/C are dominant in Makassar, similar to most areas in Indonesia. Mutations in BCP which might be associated with severity of liver disease are less common.

Humanization of high affinity anti-HBs antibody by using human consensus sequence and modification of selected minimal positional template and packing residues

We had earlier reported the construction and characterization of a high affinity recombinant scFv generated from a potential neutralizing mouse monoclonal antibody against the Hepatitis B surface antigen. In this report we describe the humanization of this scFv by grafting its antigen binding site onto framework of the human consensus sequence of highest similarity. We have used molecular modeling to alter not only the clearly permissible residues but also several minimal positional template and V(H)/V(L) interface residues. The humanized scFv retains the binding characteristic of the mouse monoclonal even under conditions that usually destabilize antigen antibody interactions. This high affinity humanized scFv provides a basis for the development of prophylactic/therapeutic molecules.

Occult hepatitis B virus infection in HIV-infected patients: Evaluation of biochemical, virological and molecular parameters

AIM

To determine the prevalence of occult hepatitis B virus (HBV) infection in a group of human immunodeficiency virus (HIV)-infected Brazilian patients and to investigate its association with biochemical, virological and molecular features.

METHODS

Sera from 43 patients positive for HBV core antibody and negative for HBV surface antigen (HBsAg) were tested for HBV DNA positivity by semi-nested PCR. HBV loads were assessed by real-time PCR. S gene was cloned and sequenced for HBV isolates from 3 patients. HBsAg expression of these cases was performed in HuH7 cells.

RESULTS

HBV DNA was found in 6/43 (14%) samples, all except one associated with low viral loads. Occult HBV infection was further correlated with anti-hepatitis C virus (anti-HCV) antibodies positivity, but not with alanine aminotransferase (ALT) elevated levels. S gene sequences derived from three patients were determined. Two of them displayed mutations that may explain HBsAg negativity. In the first one, a stop codon mutation was found at position 216 in the C-terminal end of HBsAg. In the second patient, E164D and I195M substitutions in HBsAg, associated with lamivudine-resistance mutations in the polymerase were identified. As expected, all clones showing those mutations displayed undetectable or very low levels of HBsAg.

CONCLUSION

Occult HBV infection was frequent in HIV-infected patients, was not associated with ALT elevation but significantly correlated with HCV seropositivity. The low viremia and the detection of HBsAg mutants confirm that multifactorial mechanisms are involved in occult HBV infection. HBV molecular monitoring should be employed for an adequate management of HBV/HIV co-infected patients.

Prevalence of hepatitis B virus infection among women at reproductive age at a German university hospital

BACKGROUND

Mother to infant transmission of hepatitis B virus (HBV) represents a major factor in maintaining chronic infection and depends on the degree of maternal infectivity status.

OBJECTIVES

To examine the seroprevalence of hepatitis B virus surface antigen (HBsAg) in women at reproductive age admitted to the Department of Gynaecology at a German university hospital.

STUDY DESIGN

The seroprevalence of hepatitis B surface antigen (HBsAg) in 5518 women at reproductive age was examined, HBsAg-positive samples were tested for additional HBV markers to verify the infection status.

RESULTS

Out of 5518 samples from women at reproductive age, 88 women (1.59%) were positive for HBsAg and 7 of these HBV-positive women (7.95%) were additionally positive for HBeAg. The majority of the study population were German citizens, however most HBV infected persons originated from countries with a high HBV prevalence. The HBV seroprevalence in our study group is about two times higher compared to the average seroprevalence in the German citizen adult population, thus probably resulting in an underestimation of the infection rate in a multinational setting.

CONCLUSIONS

Screening for HBsAg during pregnancy is still necessary and important for reduction of perinatal HBV transmission even in countries with low HBV prevalence.

Feasibility study of inhaled hepatitis B vaccine formulated with tetradecylmaltoside

This study was designed to test the hypothesis that formulation of hepatitis B vaccine with tetradecyl-beta-maltoside (TDM) enhances the immune response after pulmonary administration in a rodent model. Commercially available recombinant hepatitis B vaccine (rHBV) was formulated with varying concentrations of TDM and administered intratracheally to anesthetized male Sprague-Dawley rats. rHBV administered intramuscularly at doses of 2 and 4 microg served as positive controls. All formulations were administered on days 0 and 14 and the immune response was evaluated for 28 days. Specific antibodies generated to HBsAg were analyzed by ELISA. Safety studies were carried out by measuring the levels of alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and tumor necrosis factor alpha (TNF-alpha) in bronchoalveolar lavage (BAL) fluid. There was a significant increase in the immune response when the vaccine was administered intramuscularly at a dose of 4 microg. Only a modest increase in the immune response was observed when plain rHBV was administered intratracheally at the same dose. However, a pulmonary formulation of 4 microg rHBV plus 0.5% TDM produced a fourfold increase in the immune response compared to plain rHBV administered via the pulmonary route. No increase in immune response was observed for formulations containing rHBV plus 0.125% or 0.25% TDM. The levels of ALP and LDH in the BAL fluid suggest that the hepatitis B vaccine plus TDM formulations cause some injury to the lungs after the first intratracheal instillation of the formulation; however, the enzyme levels tended to be lower after the second instillation. The level of TNF-alpha in the BAL fluid of TDM-treated rats was substantially lower than that in rats treated with the positive control substance, sodium dodecyl sulfate. Overall, rHBV formulated with TDM increases the immune response after pulmonary administration, and pulmonary formulation of rHBV plus TDM could be used as an alternative to needle-based delivery of hepatitis B vaccine.

The association of complex liver disorders with HBV genotypes prevalent in Pakistan

Background

Genotyping of HBV is generally used for determining the epidemiological relationship between various virus strains and origin of infection mostly in research studies. The utility of genotyping for clinical applications is only beginning to gain importance. Whether HBV genotyping will constitute part of the clinical evaluation of Hepatitis B patients depends largely on the availability of the relevance of the evidence based information. Since Pakistan has a HBV genotype distribution which has been considered less virulent as investigated by earlier studies from south East Asian countries, a study on correlation between HBV genotypes and risk of progression to further complex hepatic infection was much needed

Methods

A total of 295 patients with HBsAg positive were selected from the Pakistan Medical Research Council's (PMRC) out patient clinics. Two hundred and twenty six (77%) were males, sixty nine (23%) were females (M to F ratio 3.3:1).

Results

Out of 295 patients, 156 (53.2%) had Acute(CAH), 71 (24.2%) were HBV Carriers, 54 (18.4%) had Chronic liver disease (CLD) Hepatitis. 14 (4.7%) were Cirrhosis and HCC patients. Genotype D was the most prevalent genotype in all categories of HBV patients, Acute (108), Chronic (39), and Carrier (53).

Cirrhosis/HCC (7) were HBV/D positive. Genotype A was the second most prevalent with 28 (13%) in acute cases, 12 (22.2%) in chronics, 14 (19.7%) in carriers and 5 (41.7) in Cirrhosis/HCC patients. Mixed genotype (A/D) was found in 20 (12.8%) of Acute patients, 3 (5.6%) of Chronic and 4 (5.6%) of carriers, none in case of severe liver conditions.

Conclusion

Mixed HBV genotypes A, D and A/D combination were present in all categories of patients except that no A/D combination was detected in severe conditions. Genotype D was the dominant genotype. However, genotype A was found to be more strongly associated with severe liver disease. Mixed genotype (A/D) did not significantly appear to influence the clinical outcome.

Molecular virology of hepatitis B virus for clinicians

This article reviews the molecular biology of the hepatitis B virus in an effort to explain its natural history from a molecular perspective. The life cycle of the virus, with special attention to virus replication, polypeptide production, and morphogenesis, is described. The way in which these steps may influence the natural history of viral pathogenesis, as well as the effectiveness of interventions, receives special consideration.

Molecular epidemiology of Hepatitis B virus genotypes in Pakistan

Background

Eight genotypes of Hepatitis B virus designated A-H, have been known but in Pakistan, no such data is available on the prevalent HBV genotypes. Therefore, the subject study was conducted to determine HBV genotypes in the indigenous Pakistani population.

Methods

A total of 690 individuals were enrolled for HBV screening with EIA and nested PCR. Positive samples were further analyzed to determine HBV genotypes (A-F) by multiplex-PCR using type specific primers.

Results

110 (15.94%) individuals were positive for HBV, including 64% males and 36% females. Out of these, 66 samples (65.34%) were classified into genotype D, 27 (26.73%) were of genotype B while 5(4.95%) had genotype A. In 3 (2.98%) samples, multiple genotypes were detected (genotype A+B; 2(1.99%) and genotypes B+D; 1(0.99%). Nine (8.18%) samples remained untyable.

Conclusion

In Asia, genotypes B and C are the most prevalent but our study reveals that genotype D is predominant and HBV infection constitutes a significant health problem in Pakistan.

Common genotypes of Hepatitis B virus prevalent in injecting drug abusers (addicts) of North West Frontier Province of Pakistan

BACKGROUND

The epidemiological significance of Hepatitis B virus genotypes has been well established and becoming an essential concern day by day however, much little is known about the mixed infection with more than one Hepatitis B virus genotypes and their clinical relevance.

METHODS

Intravenous drug abusers are considered as a major risk group for the acquisition and transmission of blood borne infections like hepatitis B, however, in Pakistan, no such data has ever been reported about the epidemiology of HBV and its genotypes in Injecting Drug Users. 250 individuals were analyzed for hepatitis B virus genotypes after prior screening with serological assay for the detection of HBsAg.

RESULTS

56 (22.4%) individuals were found positive on ELSIA for HBsAg. The genotype distribution was found to be as: genotype D, 62.5%; genotype A, 8.92% while 28.57% individuals were found to be infected with a mixture of genotype A and D.

CONCLUSION

There is an urgent need of the time to develop public health care policies with special emphasis towards the control of HBV transmission through high risk groups especially Injecting Drug Users.

Serology based disease status of Pakistani population infected with hepatitis B virus

Background

The infection rate of hepatitis B virus is continuously increasing in Pakistan. Therefore, a comprehensive study of epidemiological data is the need of time.

Methods

A total of 1300 individuals were screened for HBV infection markers including HBsAg, anti-HBsAg, HBeAg and anti-HBcAg. The association of these disease indicators was compared with patients' epidemiological characteristics like age, socio-economic status and residential area to analyze and find out the possible correlation among these variables and the patients disease status.

Results

52 (4%) individuals were found positive for HBsAg with mean age 23.5 ± 3.7 years. 9.30%, 33.47% and 12% individuals had HBeAg, antibodies for HBsAg, and antibodies for HBcAg respectively. HBsAg seropositivity rate was significantly associated (p = 0.03) with the residing locality indicating high infection in rural areas. Antibodies titer against HBsAg decreased with the increasing age reflecting an inverse correlation.

Conclusion

Our results indicate high prevalence rate of Hepatitis B virus infection and nationwide vaccination campaigns along with public awareness and educational programs are needed to be practiced urgently.

Improved multiplex-PCR to identify hepatitis B virus genotypes A-F and subgenotypes B1, B2, C1 and C2

BACKGROUND

There are eight genotypes (A-H) and numerous subgenotypes of hepatitis B virus (HBV). The genotype has been shown to affect the course of HBV infection.

OBJECTIVES

To develop an efficient genotyping and subgenotyping method for large-scale epidemiological surveys of HBV infection in countries with high prevalence of HBV B and C such as China.

STUDY DESIGN

We designed genotype and subgenotype-specific primer pairs, and adjusted PCR conditions for a multiplex-PCR using common Taq polymerase to identify HBV genotypes A-F in one reaction and for the main subgenotypes B1/B2 and C1/C2 in another reaction.

RESULTS

We have developed a multiplex-PCR system, which specifically amplifies DNA of HBV genotypes and the corresponding main subgenotypes B and C from the sera of HBV patients. Our patients were infected with HBV of subgenotypes B2 (n=18), C1 (n=2) and C2 (n=48). Eleven patients were doubly infected and three showed a triple infection with HBV A, B and C.

CONCLUSIONS

The low-cost multiplex-PCR for identification of HBV genotypes A-F and main subgenotypes of HBV B and C, is rapid, reliable and sufficient for large-scale epidemiological surveys and clinical studies.

HepSEQ: International Public Health Repository for Hepatitis B

HepSEQ is a repository for an extensive library of public health and molecular data relating to hepatitis B virus (HBV) infection collected from international sources. It is hosted by the Centre for Infections, Health Protection Agency (HPA), England, United Kingdom. This repository has been developed as a web-enabled, quality-controlled database to act as a tool for surveillance, HBV case management and for research. The web front-end for the database system can be accessed from . The format of the database system allows for comprehensive molecular, clinical and epidemiological data to be deposited into a functional database, to search and manipulate the stored data and to extract and visualize the information on epidemiological, virological, clinical, nucleotide sequence and mutational aspects of HBV infection through web front-end. Specific tools, built into the database, can be utilized to analyse deposited data and provide information on HBV genotype, identify mutations with known clinical significance (e.g. vaccine escape, precore and antiviral-resistant mutations) and carry out sequence homology searches against other deposited strains. Further mechanisms are also in place to allow specific tailored searches of the database to be undertaken.

Hepatitis B virus genotype G monoinfection and its transmission by blood components

An acute hepatitis B virus (HBV) infection was diagnosed in a regular apheresis (plasma/platelet) donor by the hepatitis B surface antigen (HBsAg) assay and minipool nucleic acid amplification technology (NAT). The acute infection was confirmed by detection of anti-HBc (IgM) and anti-HBs 2 weeks later. The donor showed no clinical symptoms and had normal alanine aminotransferase levels. He had a history of weekly apheresis plasma or platelet donations. Archived material from the donor and the respective recipients was investigated by sensitive HBV NATs as part of a look-back procedure. HBV DNA was detectable in previous donations as well as in two recipients transfused with platelet concentrates. The rare HBV genotype G was identified in all HBV-DNA-positive samples. Strong evidence of genotype G monoinfection was obtained by clonal sequencing, HBV genotype line probe assay, genotype-specific NATs, and restriction pattern analysis. In contrast to previously described genotype G infections, which all appeared as coinfections with genotype A, neither the hepatitis B e antigen (HBeAg) nor anti-HBe was detectable in any of the samples. This shows that HBeAg is dispensable for viral replication. The delay in detecting HBsAg in both the donor and recipient samples may be explained by either decreased genotype G-specific synthesis of incomplete viral forms in early HBV infection or the lower sensitivity to genotype G of the current HBsAg assays. In conclusion, this reported case of an HBV infection was caused exclusively by genotype G.

Neutralization epitope responsible for the hepatitis B virus subtype-specific protection in chimpanzees

Neutralizing monoclonal antibody (BX-182) directed against the d determinant of hepatitis B virus (HBV) surface antigen protected chimpanzees from infection by HBV subtype adw but not by subtype ayw, as demonstrated by intravenously inoculating a mixture of the antibody with the respective subtype of the virus. To elucidate the mechanism underlying the subtype-specific protection, a combinatorial approach of screening random peptide phage libraries, bioinformatics, and structure analysis was used in this study to identify the neutralization epitope responsible for the observed protection. The epitope was mapped at the N terminus of the pre-S1 region of the hepatitis B surface antigen between residues 17 and 21, of which the residues Val-18/Pro-19 were critical for antibody binding. Alignment of amino acid sequences derived from diverse genetic variants of HBV revealed that the epitope was present in ad subtypes and in their corresponding genotypes A, B, C, F, and H. By contrast, this epitope was not found in a majority of ay subtypes or in genotypes D, E, and G, where the antigenic residues Val-18/Pro-19 within the epitope were replaced by Thr/Ser, Thr/Thr, or Ala/Ser, respectively, resulting in a drastic conformational change of the epitope. These data indicate that, by binding discriminately to the subtype "d" epitope in the pre-S1 region, neutralizing antibody BX-182 protects chimpanzees from HBV infection in a subtype-specific manner, suggesting a potential escape mechanism for HBV genetic variants.

Changing patterns of hepatitis B infection in Italy and NAT testing for improving the safety of blood supply

In Italy, as in most industrialized countries, the burden of hepatitis B has progressively declined in recent decades as a consequence of general improvements in hygiene and standard of living, the introduction of several public health measures, refinement in blood screening and the implementation of specific vaccination programmes. Universal hepatitis B vaccination for all infants and adolescents as well as individuals at increased risk has resulted in considerable progress towards prevention and control of HBV infection. The residual risk of transmitting blood-borne viruses through transfusion is currently very low. Nucleic acid testing can shorten the window period and, consequently, further reduce the risk of viral transmission. Blood donor screening for HCV by NAT was initiated in Italy in 2001 and became mandatory in June 2002. NAT for HIV is currently mandatory in four regions, not mandatory but almost universally performed in another thirteen regions, and not yet introduced in the remaining four regions. NAT for HBV is currently mandatory in four regions and under evaluation in the remaining. NAT for HBV may be a useful tool in detecting acute viral infections in the window phase as well as the occult infections. Its efficacy in improving the safety of blood supply is expected to be higher in countries with intermediate/high endemicity, where anti-HBc antibody screening cannot be routinely performed. There is agreement that, at present, the implementation of HBV DNA testing will not allow for discontinuation of screening for HBsAg.

Molecular epidemiology of hepatitis B virus in Latin America

Hepatitis B virus (HBV) is an etiological agent of acute and chronic liver disease existing throughout the world. The high genetic variability of HBV is reflected by eight genotypes (A to H), each one with a particular geographical prevalence. The global pattern of HBV genotypes is associated with the distribution of human populations among the different continents and may reflect the patterns of human migrations. Genotypes F and H are considered indigenous to Latin America. The most prevalent genetic group of Central and South America, genotype F, is subdivided into two subtypes and five clusters associated with defined geographic areas. Genotype H has been described in Mexico and Central America. This pattern provides a tool to reconstruct the initial immigration of ancestral Amerindians from Asia and their further spread through Central and South America. Other HBV genotypes found in different Latin American countries may reflect migration from other geographical areas into the region. Genotypes A and D are the signature of the European colonization that started in the sixteenth century, including slave trade from Africa. Genotypes B and C indicate the arrival of people from Southeast Asia. The impact of HBV genotypes on the natural course of HBV infection and response to treatment has been studied recently and controversial results have been obtained. The majority of the current information concerns with genotypes B and C. In contrast, very few data are available on the Latin American HBV genotypes F and H. It has been reported that liver failure and death may be more frequent in patients infected with genotype F. More studies are needed to assess the association between H13V genotypes and clinical course of infection, especially in Latin America.

Complete genomic sequence and phylogenetic relatedness of hepatitis B virus isolates from Iran

Hepatitis B virus (HBV) is one of the main etiological agents of acute and chronic liver disease that is still a major public health problem in the world. Numerous HBV isolates have grouped into eight genotypes, A to H, based on the complete genome sequence. To date, no study has been carried out on the complete HBV genome sequence in Iran. The objective of this study was to investigate the complete genome sequence organization and phylogenetic analysis of the five HBV strains, which obtained from Iranian chronic infected patients. Results showed that Iranian strains were closely related to each other, with 97-100% nucleotide similarity. Phylogenetic analysis based on the complete genome sequences and the precore/core gene sequences revealed that all strains were of genotype D, sub-genotype D1 with bootstrap value 100 and 99%, respectively. The S gene encoded Arg122, Pro127, and Lys160 corresponding to subtype ayw2. Iranian HBV isolates had closely related with Turkish HBV strains. All strains had a nucleotide length of 3,182 base pair (bp) except IR-P4 strain, with a 3,185 bp in length and with a unique Phe89 insertion in the X gene. The intragenotypic divergence of the complete genome sequence of Iranian strains was 1.8% and the intergenotypic in genotype D was 3.8% and with the other genotypes was 7.9-15.4%. In conclusion, this study revealed that the HBV genotype D, sub-genotype D1, subtype ayw2 dominates in the Iranian infected patients. A single Phe89 insertion in the X gene of the one Iranian strain with an unforeseen length of 3185 bp was identified.