A genotype of hepatitis D virus that occurs in northern South America

Characterization of the Genotypic Profile of Hepatitis Delta Virus: Isolation of HDV Genotype-1 in the Western Amazon Region of Brazil

The hepatitis delta virus (HDV) is a hepatotropic subvirus that is dependent on the hepatitis B virus (HBV) and supplies the viral envelope containing the surface antigen of hepatitis B. Viral genetic diversity is related to the geographical origin of the isolates, and there are at least eight genotypes that are referred to as HDV-1 through HDV-8. HDV-3 is responsible for epidemics of severe and fulminant hepatitis, which are common in northeastern South America. HDV-3 is prevalent in the Brazilian Amazon and is associated with the increased aggressiveness of HDV infections. Although isolated, the characteristics of the clinical presentation of HDV-1 in the Amazon region have not yet been clearly reported.

OBJECTIVE

This study aims to assess the genotypic and clinical characteristics of individuals with the HDV-1 genotype in the western Amazon region.

METHODS

The HDV was genotyped by nested PCR-RFLP and sequencing from serum samples of 56 patients with HBV/HDV infection. The genotypes were correlated with the clinical characteristics presented by patients with HBV/HDV infection.

RESULTS

A prevalence of 92.3% for the HDV-3 genotype (n = 48) and 7.6% (n = 4) for the HDV-1 genotype was observed.

CONCLUSION

To date, this is the most extensive clinical study of HDV-1 genotype infections in the nonindigenous population of Western Amazonia.

Comprehensive analysis of mutations in the hepatitis delta virus genome based on full-length sequencing in a nationwide cohort study and evolutionary pattern during disease progression

Delta hepatitis, caused by co-infection or super-infection of hepatitis D virus (HDV) in hepatitis B virus (HBV) -infected patients, is the most severe form of chronic hepatitis, often progressing to liver cirrhosis and liver failure. Although 15 million individuals are affected worldwide, molecular data on the HDV genome and its proteins, small and large delta antigen (S-/L-HDAg), are limited. We therefore conducted a nationwide study in HBV-HDV-infected patients from Iran and successfully amplified 38 HDV full genomes and 44 L-HDAg sequences from 34 individuals. Phylogenetic analyses of full-length HDV and L-HDAg isolates revealed that all strains clustered with genotype 1 and showed high genotypic distances to HDV genotypes 2 to 8, with a maximal distance to genotype 3. Longitudinal analyses in individual patients indicated a reverse evolutionary trend, especially in L-HDAg amino acid composition, over time. Besides multiple sequence variations in the hypervariable region of HDV, nucleotide substitutions preferentially occurred in the stabilizing P4 domain of the HDV ribozyme. A high rate of single amino acid changes was detected in structural parts of L-HDAg, whereas its post-translational modification sites were highly conserved. Interestingly, several non-synonymous mutations were positively selected that affected immunogenic epitopes of L-HDAg towards CD8 T-cell- and B-cell-driven immune responses. Hence, our comprehensive molecular analysis comprising a nationwide cohort revealed phylogenetic relationships and provided insight into viral evolution within individual hosts. Moreover, preferential areas of frequent mutations in the HDV ribozyme and antigen protein were determined in this study.

Hepatitis D virus coinfection and superinfection

HDV is a defective RNA pathogen requiring the simultaneous presence of HBV to complete its life cycle. Two major specific patterns of infection have been described: the coinfection with HDV and HBV of a susceptible, anti-HBs-negative individual, or the HDV superinfection of a chronic HBV carrier. Coinfection mostly leads to the eradication of both agents, whereas the majority of patients with HDV superinfection evolve to chronic HDV infection and hepatitis. Chronic HDV infection worsens the preexisting HBV-related liver damage. HDV-associated chronic liver disease (chronic hepatitis D) is characterized by necroinflammation and the relentless deposition of collagen culminating, within a few decades, into the development of cirrhosis and hepatocellular carcinoma.

Reduced genetic distance and high replication levels increase the RNA recombination rate of hepatitis delta virus

Hepatitis delta virus (HDV) replication is carried out by host RNA polymerases. Since homologous inter-genotypic RNA recombination is known to occur in HDV, possibly via a replication-dependent process, we hypothesized that the degree of sequence homology and the replication level should be related to the recombination frequency in cells co-expressing two HDV sequences. To confirm this, we separately co-transfected cells with three different pairs of HDV genomic RNAs and analyzed the obtained recombinants by RT-PCR followed by restriction fragment length polymorphism and sequencing analyses. The sequence divergence between the clones ranged from 24% to less than 0.1%, and the difference in replication levels was as high as 100-fold. As expected, significant differences were observed in the recombination frequencies, which ranged from 0.5% to 47.5%. Furthermore, varying the relative amounts of parental RNA altered the dominant recombinant species produced, suggesting that template switching occurs frequently during the synthesis of genomic HDV RNA. Taken together, these data suggest that during the host RNA polymerase-driven RNA recombination of HDV, both inter- and intra-genotypic recombination events are important in shaping the genetic diversity of HDV.

Molecular epidemiology of hepatitis delta virus in the Western Pacific region

BACKGROUND

Hepatitis delta virus (HDV) is a defective RNA virus requiring the presence of the hepatitis B virus (HBV) for the completion of its life cycle. Active replication of HDV can lead to severe hepatitis, and although present worldwide has an irregular geographical distribution, especially in the Asian Pacific region.

OBJECTIVES

The aim of this study was to determine the prevalence and molecular epidemiology of HDV isolates in Oceania following the 1998 evaluation of the hepatitis B vaccine program.

STUDY DESIGN

Sera collected from 184 hepatitis B surface antigen (HBsAg) positive Pacific Islanders living in Micronesia, Polynesia and Melanesia were tested for HDV RNA.

RESULTS

Twenty of 54 patients with chronic hepatitis B (CHB) from Kiribati were positive for serum HDV RNA (37%), whilst sera from patients with CHB from Tonga (59), Fiji (42) and Vanuatu (29) were negative. The mean HDV RNA load for the 20 samples was 7.00log10copies/mL. Phylogenetic analysis revealed that the Kiribati HDV isolates were of genotype 1 and clustered with a previously published isolate from Nauru forming a distinct clade of Pacific HDV. All Micronesian isolates contained a serine at codon 202 of large hepatitis delta antigen (L-HDAg) demonstrating possible relatedness to strains of HDV-1 of African origin.

CONCLUSIONS

This study has confirmed endemic HDV infection in Micronesia and identified Kiribati as having amongst the highest prevalence for HDV viraemia in patients with CHB. Further investigations are ongoing into the origins of this unique HDV Pacific strain, and its inter-relationship with HBV.

Characterization of hepatitis delta virus in sub-Saharan Africa

Hepatitis D virus (HDV) is a satellite of hepatitis B virus (HBV), and infection with this virus aggravates acute and chronic liver disease. While HBV seroprevalence is very high across sub-Saharan Africa, much less is known about HDV in the region. In this study, almost 2,300 blood serum samples from Burkina Faso (n=1,131), Nigeria (n=974), Chad (n=50), and the Central African Republic (n = 118) were screened for HBV and HDV. Among 743 HBsAg-positive serum samples, 74 were positive for HDV antibodies and/or HDV RNA, with considerable differences in prevalence, ranging from <2% (pregnant women from Burkina Faso) to 50% (liver patients from Central African Republic). HDV seems to be much more common in chronic liver disease patients in the Central African Republic (CAR) than in similar cohorts in Nigeria. In a large nested mother-child cohort in Burkina Faso, the prevalence of HDV antibodies was 10 times higher in the children than in their mothers, despite similar HBsAg prevalences, excluding vertical transmission as an important route of infection. The genotyping of 16 full-length and 8 partial HDV strains revealed clade 1 (17/24) in three of the four countries, while clades 5 (5/24) and 6 (2/24) were, at least in this study, confined to Central Nigeria. On the amino acid level, almost all our clade 1 strains exhibited a serine at position 202 in the hepatitis D antigen, supporting the hypothesis of an ancient African HDV-1 subgroup. Further studies are required to understand the public health significance of the highly varied HDV prevalences in different cohorts and countries in sub-Saharan Africa.

Hepatitis delta virus genotype-1 alone cocirculates with hepatitis B virus genotypes A and D in Pakistan

INTRODUCTION

Hepatitis delta virus (HDV) and hepatitis B virus (HBV) have been identified as major causes of morbidity and mortality in Pakistan because HDV causes infection only in the presence of HBV. Coinfection with both hepatitis viruses can lead to a more severe acute form of disease and to an increased risk of fulminant hepatitis. HDV infection differs in its distribution and severity depending on the geographical distribution, and several genotypes of HDV have been identified so far.

OBJECTIVES

The aim of the present study was to establish the HDV and HBV genotypes in chronically infected Pakistani patients and to determine whether there is any correlation between HDV and HBV genotypes.

PATIENTS AND METHODS

We studied samples from a total of 46 chronically infected HBV and HDV patients for HBV and HDV genotype analysis out of a total of 75 chronic HBV carriers enrolled. HBV and HDV genotypes were determined using type-specific PCR, followed by sequencing of PCR amplified products.

RESULTS

The results of HBV genotyping showed that 33 of 46 (71.7%) patients had genotype D, five (10.9%) had A+D mixed genotypes, whereas eight (17.3) samples were untypable. We could detect only one HDV genotype (HDV-1) prevalent in the Pakistani population. The HDV-1 genotype isolate was associated with HBV genotype D alone or in combination with A (HBV-A+D).

CONCLUSION

The present study concludes that HDV/HBV coinfection is very high in the Pakistani population and was previously underestimated. The most prevalent circulating genotypes of HBV and HDV are HDV-1 and HBV-D, respectively, in the studied area. There is no specific interaction between HBV and HDV genotypes as suggested by HDV-1/HBV-D or HDV-1/HBV-A+D coinfection. Coinfection of HDV-1 and HBV-D simply reflects the most frequent genotypes circulating in this specific geographical region of the world.

Molecular epidemiology of hepatitis B and hepatitis delta viruses circulating in the Western Amazon region, North Brazil

Background

Hepatitis B virus (HBV) and hepatitis D virus (HDV) represent important public health problems in the Western Amazon region with reported cases of fulminant hepatitis. This cross sectional study describes HBV and HDV genotypes circulating in the Brazilian Amazon region.

Methods

HBsAg positive individuals (n = 224) were recruited in Manaus/Amazonas State (130 blood donors from the Hematology and Hemotherapy Foundation from Amazonas/HEMOAM; 60 subjects from outpatient clinic) and in Eirunepe city (n = 34) from 2003–2009. Most participants (n = 153) lived in Manaus, 63 were from 20 remote isolated municipalities, 8 lived outside Amazonas State. Genotyping was based on PCR products: HBV genotype A-F specific primers, restricted length polymorphism for HDV. HDV isolates were directly sequenced (delta antigen 405 nucleotide fragment) and phylogenetic analysis performed (MEGA; neighbor-joining, Kimura’s two parameter).

Results

Most participants were young adult males and HBV mono-infection predominated (70.5%, 158/224). Among blood donors, outpatient subjects and individuals from Eirunepe, HBV/A prevailed followed by HBV/D and F (p > 0.05). HBV/A was more frequent in blood donors (p < 0.05). HBV-HDV coinfection rate was 8.5% in blood donors (11/130), 65.0% (39/60) in outpatient subjects and 47.0% (16/34) in individuals from Eirunepe. Compared to blood donors, coinfection was higher in outpatient subjects (65.0% versus 8.5%; RR = 5.0; CI 3.4-7.9; p < 0.0001) and in subjects from Eirunepe (47.0% versus 8.5%; RR = 5.5; CI 3.0-9.9; p < 0.0001). HBV-HDV coinfection rates were higher in patients from highly endemic remote cities. Only HDV genotype 3 was detected, HBV/F-HDV/3 predominated (20/38; 52.7%), followed by HBV/A-HDV/3 (31.6%; 12/38) and HBV/D-HDV/3 (15.8%; 6/38).

Conclusions

The description of HBV and HDV genotypes circulating in the western Amazon can contribute to a better understanding of their relevance on the regional epidemics. These infections are highly endemic in the Amazon where their control is challenged by its vast territorial dimension with small, hard-to-reach municipalities dispersed into the jungle and populated by diverse ethnic groups.

Development of a reverse transcription quantitative real-time PCR-based system for rapid detection and quantitation of hepatitis delta virus in the western Amazon region of Brazil

The hepatitis delta virus (HDV) is a pathogen that causes a severe and rapidly progressive disease of hepatocytes. The measurement of viral load in the peripheral blood of patients with HDV infections is important for diagnosis, treatment monitoring, and support for follow-up studies of viral replication during the course of the disease. This study reports the development of an assay capable of detecting and quantifying the abundance of HDV particles in serum samples, based on reverse-transcription quantitative PCR (RT-qPCR). Two standards for calibration were produced for determining the viral load of HDV: a cDNA cloned into a linear plasmid and a transcribed RNA. For validating this assay, 140 clinical samples of sera were used, comprising 100 samples from patients who tested positive for anti-HDV and hepatitis B virus surface antigen (HBsAg) by ELISA; 30 samples from blood donors; 5 samples monoinfected with hepatitis B virus (HBV); and 5 samples monoinfected with hepatitis C virus (HCV). The HDV RT-qPCR assay performed better when calibrated using the standard based on HDV cDNA cloned into a linear plasmid, yielding an efficiency of 99.8% and a specificity of 100% in the in vitro assays. This study represents the first HDV RT-qPCR assay developed with clinical samples from Brazil and offers great potential for new clinical efficacy studies of antiviral therapeutics for use in patients with hepatitis delta in the western Amazon region.

An update on HDV: virology, pathogenesis and treatment

Hepatitis delta is an inflammatory liver disease caused by infection with HDV. HDV is a single-stranded circular RNA pathogen with a diameter of 36 nm. HDV is classified in the genus Deltavirus and is still awaiting a final taxonomic classification up to the family level. HDV shares similarities with satellite RNA and viroids including a small circular single-stranded RNA with secondary structure that replicates through the 'double rolling circle' mechanism. The HDV RNA genome is capable of self-cleavage through a ribozyme and encodes only one structural protein, the hepatitis delta antigen (HDAg), from the antigenomic RNA. There are two forms of HDAg, a shorter (S; 22 kDa) and a longer (L; 24 kDa) form, the latter generated from an RNA editing mechanism. The S form is essential for viral genomic replication. The L form participates in the assembly and formation of HDV. For complete replication and transmission, HDV requires the hepatitis B surface antigen (HBsAg). Thus, HDV infection only occurs in HBsAg-positive individuals, either as acute coinfection in treatment-naive HBV-infected persons, or as superinfection in patients with pre-existing chronic hepatitis B (CHB). HDV is found throughout the world, but its prevalence, incidence, clinical features and epidemiological characteristics vary by geographic region. There are eight genotypes (1 to 8) distributed over different geographic areas: HDV-1 is distributed worldwide, whereas HDV-2 to 8 are seen more regionally. Levels of HDV viraemia change over the course of HDV infection, being significantly higher in patients with early chronic hepatitis than in cirrhosis. Chronic HDV infection leads to more severe liver disease than chronic HBV monoinfection with an accelerated course of fibrosis progression, an increased risk of hepatocellular carcinoma and early decompensation in the setting of established cirrhosis. Current treatments include pegylated interferon-α and liver transplantation; the latter of which can be curative. Further studies are needed to develop better treatment strategies for this challenging disease.

Frequency and Genotype of Hepatitis D Virus Infection in Patients Infected with HIV and Those Undergoing Hemodialysis

BACKGROUND

Hepatitis D virus (HDV) is a defective virus dependent on hepatitis B virus (HBV) for its replication. Due to HDV transmission routes, patients undergoing hemodialysis and those with HIV infection are at risk of acquiring HDV.

OBJECTIVES

This study was aimed to determine the frequency and genotype of HDV infection among patients with HIV infection and those undergoing hemodialysis.

PATIENTS AND METHODS

720 cases including 120 patients undergoing hemodialysis, and 600 patients with HIV infection were studied. All cases with positive results for HBsAg were evaluated for the presence of anti-HDV antibodies. Samples with Anti-HDV positive results were subjected to nested PCR for HDV-RNA confirmation, and sequenced for HDV genotype determination.

RESULTS

HBsAg was found in 9 (7.5%) of 120 patients undergoing hemodialysis, and 9 (1.5%) of 600 patients with HIV infection. 3 (33.3%) of patients undergoing hemodialysis with positive results for HBsAg, and 5 (55.5%) of cases with HIV infection and positive results for HBsAg, had positive findings for anti-HDV which were then subjected to nested PCR. The amplification results confirmed that in 3 (37.5%) samples HDV-RNA was detected. Overall 2.5% of patients undergoing hemodialysis, and 0.8% of cases infected with HIV had positive results for anti-HDV and 1.7% and 0.2% of cases undergoing hemodialysis and patients infected with HIV had positive findings for HDV-RNA respectively. All of the HDV isolates were clustered in clade 1.

CONCLUSIONS

The survey showed that overall HDV frequency was not high in our high risk cases. Therefore, practitioners and health care managers should become aware of the risk of dual infection with HBV and HDV especially in high risk patients.

Development and assessment of a novel real-time PCR assay for quantitation of hepatitis D virus RNA to study viral kinetics in chronic hepatitis D

Hepatitis delta virus (HDV) infection is a usually severe type of viral hepatitis associated with increased mortality and rapid evolution to cirrhosis. Currently, treatment is limited to extended interferon administration and measurement of HDV RNA blood levels is essential to judge the response. The aim of this study was to develop a highly sensitive and reproducible real-time reverse transcriptase-polymerase chain reaction (real-time RT-PCR) for the quantitation of circulating HDV RNA of all clades (1-8), and assess its usefulness in the follow-up of patients. The amplification was combined with molecular beacon technology using the LightCycler 2.0 system. The assay was specific and showed linearity over a wide range from 13 to 13 × 10(10) copies/mL. The 95% detection limit was 43.2 copies/mL. Intra-assay reproducibility, as expressed by the coefficient of variation, ranged from 1.84 to 18.61%, whereas the corresponding estimates for the inter-assay variability ranged from 0.57 to 10.18%. Finally, the dynamic profiles of six patients regarding virological (HDV RNA, HBV DNA), biochemical and serological data were constructed. We were able to observe that most patients who were treated with an interferon-based regime showed a significant reduction in delta viremia. In conclusion, our real-time RT-PCR for HDV RNA quantification combines high sensitivity and reproducibility in a high dynamic range, can provide important information for patient management and can be a useful tool for monitoring the response to antiviral therapies.

Development of a reverse transcription-loop-mediated isothermal amplification (RT-LAMP) system for rapid detection of HDV genotype 1

The object of this study was to develop a reverse transcription-loop-mediated isothermal amplification (RT-LAMP) assay for detecting hepatitis D virus (HDV) genotype 1. With an alignment analysis, a highly conserved sequence (nt 820-1020) was chosen as a suitable target to design LAMP primers. The optimal condition of RT-LAMP was a 25-μl reaction volume, which consists of the following components: 1·6 μmol l⁻¹ each of FIP and BIP, 0·2 μmol l⁻¹ each of F3 and B3, 1·5 μmol l⁻¹ dNTPs, 4 mmol l⁻¹ MgSO₄, 8 U Bst DNA polymerase, 2U M-MLV and 2 μl extracted RNA sample. The amplification reaction was carried out at 65°C for 50 min. Compared with conventional qualitative or quantitative real-time reverse transcription polymerase chain reaction, the results of RT-LAMP indicated a 1000-fold increase in sensitivity for detecting HDV. There was no cross-reaction for the RT-LAMP method between HDV 1 and HIV, HAV, HBV, HCV and HEV.

SIGNIFICANCE AND IMPACT OF THE STUDY

The results indicate that RT-LAMP is a simple, rapid, specific, highly sensitive and cost-effective, field-based method for detecting HDV 1. The RT-LAMP assay is an acceptable alternative to diagnose the HDV genotype 1 and to investigate its epidemiology for clinical laboratories lacking specialized equipments.

Lysine-71 in the large delta antigen of hepatitis delta virus clade 3 modulates its localization and secretion

Hepatitis delta virus (HDV) is an RNA virus and eight clades of HDV have been identified. HDV clade 3 (HDV-3) is isolated only in the northern area of South America. The outcome of HDV-3 infection is associated with severe fulminant hepatitis. Variations in the large delta antigen (LDAg) between HDV clade 1 (HDV-1) and HDV-3 have been proposed to contribute to differences in viral secretion efficiency, but which changes might be relevant remains unclear. The control of subcellular localization of LDAg has been reported to be associated with post-translational modifications, such as phosphorylation and isoprenylation. We have observed evidence for acetylation on the LDAg of HDV-3 (LDAg-3) and LDAg of HDV-1 (LDAg-1). Green fluorescent protein-fused LDAg-3 (GFP-LD3) was used to investigate the cellular distribution and secretion of the protein. Sequence alignment of LDAg amino acids suggested that lysine-71 of LDAg-3 could be an acetylation site. Expression of a mutant form of LDAg-3 with an arginine-substitution at lysine-71 (GFP-LD3K71R) showed a distribution of the protein predominantly in the cytoplasm instead of the nucleus. Western blot analyses of secreted empty viral particles (EVPs) revealed a higher amount of secreted GFP-LD3K71R compared to GFP-LD3. Furthermore, the ectopic expression of p300, a histone acetyltransferase, led to a reduction of GFP-LD3 in EVPs. By contrast, expression of three histone deacetylases (HDAC-4, -5, and -6) facilitated the secretion of GFP-LD3. Combined, our observations support the hypothesis that the acetylation status of LDAg-3 plays a role in regulating LDAg-3's localization inside the nucleus or cytoplasm, and its secretion.

Does interferon-sparing tenofovir disoproxil fumarate-based therapy have a role in the management of severe acute hepatitis delta superinfection?

Infection with hepatitis delta virus (HDV) always occurs in association with hepatitis B virus (HBV) and is a cause of significant morbidity and mortality. We present a case of severe acute HDV infection superimposed on a previously unrecognized HBV infection, in which an interferon-sparing antiviral therapy consisting of tenofovir disoproxil fumarate (TDF) and lamivudine was initiated and subsequently maintained. Evidence of successful suppression of HDV ribonucleic acid (RNA) was obtained after 65 weeks of TDF-based treatment. This was mirrored by a significant reduction in the levels of HBV DNA and HBV surface antigen. HDV RNA subsequently rebounded after our patient stopped antiviral therapy of his own accord. Interferon-sparing TDF-based antiviral therapy was safe and effective in achieving HDV RNA suppression in acute HDV superinfection. Further research into the utility of interferon-sparing TDF-based regimes in the treatment of acute HDV infection is needed.

Design of potential siRNA molecules for hepatitis delta virus gene silencing

Hepatitis D is a liable reason of mortality and morbidity worldwide. It is caused by an RNA virus known as Hepatitis Delta Virus (HDV). Genetic studies of HDV have shown that delta antigen protein is responsible for replication of genome and play a foremost role in viral infection. Therefore, delta antigen protein may be used as suitable target for disease diagnosis. Viral activity can be restrained through RNA interference (RNAi) technology, an influential method for post transcriptional gene silencing in a sequence specific manner. However, there is a genetic variability in different viral isolates; it is a great challenge to design potential siRNA molecules which can silence the respective target genes rather than any other viral gene simultaneously. In current study two effective siRNA molecules for silencing of HDV were rationally designed and validated using computational methods, which may lead to knockdown the activity of virus. Thus, this approach may provide an insight for the chemical synthesis of antiviral RNA molecule for the treatment of hepatitis D, at genome level.

Interferon-α for patients with chronic hepatitis delta: a systematic review of randomized clinical trials

BACKGROUND

Hepatitis delta virus (HDV) infection therapy is unclear. This systematic analysis aimed to clarify the evidence on the efficacy of interferon (IFN)-α-based therapy in HDV.

METHODS

We performed a systematic search on electronic databases including MEDLINE (1970 to January 2011), Web of Science, The Cochrane Library and ClinicalTrials.gov. Randomized clinical trials (RCTs) comparing IFN-α-based therapy with either another drug, placebo or no intervention were included. We excluded paediatric studies. We calculated relative risks (RRs) for comparison of treatment options on the primary outcome measure, which was defined as undetectable levels of HDV RNA and normal alanine aminotransferase at end of treatment (EOT; 1 year).

RESULTS

Nine RCTs were included. Seven trials evaluated the treatment with IFN-α (n=132). The remaining two trials evaluated treatment with pegylated (PEG)-IFN-α (n=45). We found that 1-year treatment with high-dose IFN-α achieved better primary outcome rates than with PEG-IFN-α (RR=4.14, 95% CI 1.00, 17.14). Data for 1-year treatment with low-dose IFN-α compared with PEG-IFN-α were similar (RR=2.83, 95% CI 0.65, 12.40), as were low-dose IFN-α versus high-dose IFN-α (RR=0.68, 95% CI 0.31, 1.50). High-dose IFN-α and PEG-IFN-α reached similar HDV RNA suppression 24 weeks after EOT (RR=1.00, 95% CI 0.51, 1.97). None of the 55 patients assigned to no intervention obtained undetectable levels of HDV RNA and only one patient achieved normalization of alanine aminotransferase level.

CONCLUSIONS

Based on available RCTs, 1-year high-dose IFN-α monotherapy appears to be more effective than PEG-IFN-α for treatment of HDV patients, with efficacy rates of approximately 30%. There is a lack of head-to-head comparisons. Combination therapies and longer treatment duration need to be investigated.

Meta-analysis: antiviral treatment for hepatitis D

BACKGROUND

There is no satisfactory treatment for patients with hepatitis D (HDV).

AIM

To evaluate treatment for HDV using meta-analysis.

METHODS

Medline, Scopus, Cochrane Library and ISI Web of Knowledge searches using the textwords 'Hepatitis D', 'therapy', "interferon", "peginterferon", "pegylated interferon", "lamivudine", "pegifn", "ifn" and "Hepatitis D", and abstracts from major Gastroenterology/Liver meetings.

ENDPOINTS

end of treatment biochemical (biochemical EOT) and virological response (virological EOT), end of follow-up virological response (EOFUP VR), histological improvement and intrahepatic HDAg clearance.

RESULTS

We included randomised clinical trials (RCTs) comparing Group A: interferon-A (IFNa) vs. no treatment (three RCTs, n ;= ;137 patients), Group B: low dose vs. high dose IFNa (two RCTs, n ;= ;60), Group C: IFNa ;+ ;lamivudine vs. IFNa (two RCTs, n ;= ;48) and Group D: pegylated IFNa (PEG-IFNa) vs. other medications (two RCTs, n ;= ;157). Group A. IFNa was better for biochemical EOT [OR, 0.11 (95% CI, 0.04-0.2)] and virological EOT [OR, 0.08 (95% CI, 0.03-0.2)], but not for EOFUP VR. Group B. High dose IFNa was better for biochemical EOT [OR, 0.24 (95% CI,0.08-0.73)] and virological EOT [OR, 0.27 (95% CI, 0.1-0.74)]. Group C. There was a trend favouring histological improvement [OR, 2.9 (95% CI, 0.6-13.4)]. Group D. PEG-IFNa was better for virological EOT [OR, 0.419 (95% CI, 0.18-0.974)], EOFUP VR [OR, 0.404 (95% CI, 0.189-0.866)] and improvement in necroinflammatory activity [OR, 0.308 (95% CI, 0.129-0.732)].

CONCLUSIONS

Long-term suppression of HDV RNA by IFNa is not maintained despite an end of treatment response; adding lamivudine is not beneficial. PEG-IFNa is superior to other medications with respect to EOT and EOFUP. New RCTs should test combinations of PEG-IFNa and newest antivirals.

Control of ADAR1 editing of hepatitis delta virus RNAs

Hepatitis delta virus (HDV) uses ADAR1 editing of the viral antigenome RNA to switch from viral RNA replication to packaging. At early times in the replication cycle, the virus produces the protein HDAg-S, which is required for RNA synthesis; at later times, as result of editing at the amber/W site, the virus produces HDAg-L, which is required for packaging, but inhibits further RNA synthesis as levels increase. Control of editing during the replication cycle is essential for the virus and is multifaceted. Both the rate at which amber/W site editing occurs and the ultimate amount of editing are restricted; moreover, despite the nearly double stranded character of the viral RNA, efficient editing is restricted to the amber/W site. The mechanisms used by the virus for controlling editing operate at several levels, and range from molecular interactions to procedural. They include the placement of editing in the HDV replication cycle, RNA structural dynamics, and interactions of both ADAR1 and HDAg with specific structural features of the RNA. That HDV genotypes 1 and 3 use different RNA structural features for editing and control the process in ways related to these features underscores the critical roles of editing and its control in HDV replication. This review will cover the mechanisms of editing at the amber/W site and the means by which the virus controls it in these two genotypes.

Current hepatitis delta virus type 1 (HDV1) infections in central and eastern Turkey indicate a wide genetic diversity that is probably linked to different HDV1 origins

Hepatitis delta virus (HDV) is a subviral pathogen of humans, a satellite of hepatitis B virus (HBV) that induces severe acute and chronic liver diseases. The genus Deltavirus consists of eight clades or genotypes, with HDV1 being ubiquitous and frequently characterized. In Turkey, HDV1 infection is highly endemic among HBsAg carriers, especially in the southeastern region. In this study, we analyzed 34 samples from patients who were chronically infected with HBV/HDV, originating from 22 cities of rural regions in the central and eastern parts of Turkey, in order to determine the levels of viral replication and genetic diversity. HDV RNA levels ranged between 3.02 and 8.75 Log copies/mL, and HBV DNA was detected in 25 samples (73.5%), with values ranging from 2.53 to 5.30 Log copies/mL. Analysis of nucleotides 900-1280 of HDV genomes (n = 34) and full-length (n = 17) sequences indicated that all of the strains belonged to genotype HDV1. However, a high genetic diversity was observed among the isolates, with a mean full-length dissimilarity score of 13.05%. HDV sequences clustered with sequences from Western Europe (n = 11), Eastern Europe and Asia (n = 19) or Africa (n = 4). HDV1 isolates related to strains of African origin had a serine residue instead of an alanine at position 202 of the large delta protein. HBV preS1 sequences obtained for 34 isolates indicated an HBV/D genotype in all cases. Taken together, our results indicate that in Turkey, where HBV-HDV dual infection is highly endemic, both viruses have high levels of replication, and HDV strains exhibit wide genetic diversity, which might reflect ancient evolution and/or successive outbreaks.

Hepatitis delta in HIV/HBV co-infected patients in Brazil: is it important?

OBJECTIVES

This study was carried out to evaluate the prevalence of hepatitis delta virus (HDV) among human immunodeficiency virus (HIV)/hepatitis B virus (HBV) co-infected patients from São Paulo, in the Southeast Region of Brazil.

METHODS

A total of 3259 HIV patients with serological markers for HBV were initially enrolled in the study. Among these patients, 154 (4.7%) were hepatitis B surface antigen (HBsAg)-reactive. Serum samples were obtained from 86 HBsAg-positive patients and were submitted to anti-HDV serological assay.

RESULTS

One (1.2%) HIV/HBV patient was found to be anti-HDV-positive, and the HDV infection was confirmed by PCR. Phylogenetic analysis showed that this HDV sequence grouped with other HDV genotype 1 sequences from Mediterranean European countries, suggesting that this virus has a common ancestor with HDV from that region. This patient was probably infected by sexual transmission, as he reported unprotected sexual intercourse with multiple partners over the course of many years but denied intravenous drug use or any travel to the Brazilian Amazon, an area known to have a high HDV prevalence.

CONCLUSIONS

HDV infection is infrequent in the Southeast Region of Brazil, however there have been a few cases in this region. HIV/HBV patients are at potential risk for HDV infection, therefore investigations for the presence of HDV infection must be carried out in these patients.

Complete genome sequences and phylogenetic analysis of hepatitis delta viruses isolated from nine Turkish patients

Hepatitis delta virus (HDV) is a subviral agent of hepatitis B virus (HBV), and its life cycle is dependent on HBV. It is commonly accepted that HDV has eight distinct genotypes. In this study, the complete nucleotide sequences of HDV genomes isolated from nine Turkish patients were obtained by RT-PCR using two pairs of primers that cover the entire HDV genome. PCR products were sequenced directly. The results showed that these 9 isolates were approximately 1680 base pairs in length and clustered in the genotype HDV-1 branch when phylogenetic analysis was done with the sequences together with the complete sequences of HDV genomes representing each genotype retrieved from GenBank. Analysis of a portion of the large hepatitis D antigen (L-HDAg) gene showed that sequence similarity among these Turkish isolates is between 87.4 and 97.1%, and the Turkish isolates have the most sequence similarity to HDV-1 (90.5%), while they have the least sequence similarity to HDV-3 (64.1%). Full-genome analysis indicates that the sequence similarity is between 80.7 and 95.4%, and the highest sequence similarity is 84.8% (between the Turkish isolates and HDV-1). The lowest sequence similarity is 56.4% (between the Turkish isolates and HDV-3). In conclusion, phylogenetic analysis shows that the Turkish HDV isolates belong to HDV-1.

Hepatitis Delta virus genotype 8 infection in Northeast Brazil: inheritance from African slaves?

Hepatitis Delta virus (HDV) is endemic worldwide, but its prevalence varies in different geographical areas. While in the Brazilian Amazon, HDV is known to be endemic and to represent a significant public health problem, few studies have assessed its prevalence in other regions in the country. This study evaluated the seroprevalence of HDV among HBsAg chronic carriers from Maranhão state, a region located in the Northeast of Brazil. Among 133 patients, 5 had anti-HD, of whom 3 had HDV RNA. HDV genotypes were characterized by Bayesian phylogenetic analysis of nucleotide sequences from the HDAg coding region. HDV-3 was identified in one patient who lives in Maranhão, but was born in Amazonas state (Western Amazon basin). Phylogenetic analysis shows that this HDV-3 sequence grouped with other HDV-3 sequences isolated in this state, which suggests that the patient probably contracted HDV infection there. Surprisingly, the other two patients were infected with HDV-8, an African genotype. These patients were born and have always lived in Urbano Santos, a rural county of Maranhão state, moreover they had never been to Africa and denied any contact with people from that continent. This is the first description of the HDV-8 in non-native African populations. This genotype may have been introduced to Brazil through the slaves brought to the country from the West Africa regions during the 16-18th centuries. Our results indicate that the need of clinical and epidemiological studies to investigate the presence of this infection in other areas in Brazil.

Hepatitis delta virus

Hepatitis delta virus (HDV) is a small, defective RNA virus that can infect only individuals who have hepatitis B virus (HBV); worldwide more than 15 million people are co-infected. There are eight reported genotypes of HDV with unexplained variations in their geographical distribution and pathogenicity. The hepatitis D virion is composed of a coat of HBV envelope proteins surrounding the nucleocapsid, which consists of a single-stranded, circular RNA genome complexed with delta antigen, the viral protein. HDV is clinically important because although it suppresses HBV replication, it causes severe liver disease with rapid progression to cirrhosis and hepatic decompensation. The range of clinical presentation is wide, varying from mild disease to fulminant liver failure. The prevalence of HDV is declining in some endemic areas but increasing in northern and central Europe because of immigration. Treatment of HDV is with pegylated interferon alfa; however, response rates are poor. Increased understanding of the molecular virology of HDV will identify novel therapeutic targets for this most severe form of chronic viral hepatitis.

Dynamics of hepatitis D (delta) virus genotype 3 in the Amazon region of South America

Hepatitis delta virus (HDV) is widely distributed and associated with fulminant hepatitis epidemics in areas with high prevalence of HBV. Several studies performed in the 1980s showed data on HDV infection in South America, but there are no studies on the viral dynamics of this virus. The aim of this study was to conduct an evolutionary analysis of hepatitis delta genotype 3 (HDV/3) prevalent in South America: estimate its nucleotide substitution rate, determine the time of most recent ancestor (TMRCA) and characterize the epidemic history and evolutionary dynamics. Furthermore, we characterized the presence of HBV/HDV infection in seven samples collected from patients who died due to fulminant hepatitis from Amazon region in Colombia and included them in the evolutionary analysis. This is the first study reporting HBV and HDV sequences from the Amazon region of Colombia. Of the seven Colombian patients, five were positive for HBV-DNA and HDV-RNA. Of them, two samples were successfully sequenced for HBV (subgenotypes F3 and F1b) and the five samples HDV positive were classified as HDV/3. By using all HDV/3 available reference sequences with sampling dates (n=36), we estimated the HDV/3 substitution rate in 1.07 × 10(-3) substitutions per site per year (s/s/y), which resulted in a time to the most recent common ancestor (TMRCA) of 85 years. Also, it was determined that HDV/3 spread exponentially from early 1950s to the 1970s in South America. This work discusses for the first time the viral dynamics for the HDV/3 circulating in South America. We suggest that the measures implemented to control HBV transmission resulted in the control of HDV/3 spreading in South America, especially after the important raise in this infection associated with a huge mortality during the 1950s up to the 1970s. The differences found among HDV/3 and the other HDV genotypes concerning its diversity raises the hypothesis of a different origin and/or a different transmission route.

Hepatitis B (HBV), hepatitis C (HCV) and hepatitis delta (HDV) viruses in the Colombian population--how is the epidemiological situation?

Background

Viral hepatitis B, C and delta still remain a serious problem worldwide. In Colombia, data from 1980s described that HBV and HDV infection are important causes of hepatitis, but little is known about HCV infection. The aim of this study was to determine the currently frequency of HBV, HCV and HDV in four different Colombian regions.

Methodology/Principal Findings

This study was conducted in 697 habitants from 4 Colombian departments: Amazonas, Chocó, Magdalena and San Andres Islands. Epidemiological data were obtained from an interview applied to each individual aiming to evaluate risk factors related to HBV, HCV or HDV infections. All samples were tested for HBsAg, anti-HBc, anti-HBs and anti-HCV markers. Samples that were positive to HBsAg and/or anti-HBc were tested to anti-HDV. Concerning the geographical origin of the samples, the three HBV markers showed a statistically significant difference: HBsAg (p = 0.033) and anti-HBc (p<0.001) were more frequent in Amazonas and Magdalena departments. Isolated anti-HBs (a marker of previous vaccination) frequencies were: Chocó (53.26%), Amazonas (32.88%), Magdalena (17.0%) and San Andrés (15.33%) - p<0.001. Prevalence of anti-HBc increased with age; HBsAg varied from 1.97 to 8.39% (p = 0.033). Amazonas department showed the highest frequency for anti-HCV marker (5.68%), while the lowest frequency was found in San Andrés Island (0.66%). Anti-HDV was found in 9 (5.20%) out of 173 anti-HBc and/or HBsAg positive samples, 8 of them from the Amazonas region and 1 from them Magdalena department.

Conclusions/Significance

In conclusion, HBV, HCV and HDV infections are detected throughout Colombia in frequency levels that would place some areas as hyperendemic for HBV, especially those found in Amazonas and Magdalena departments. Novel strategies to increase HBV immunization in the rural population and to strengthen HCV surveillance are reinforced by these results.

Hepatitis D virus: an update

Hepatitis D virus (HDV) infection involves a distinct subgroup of individuals simultaneously infected with the hepatitis B virus (HBV) and characterized by an often severe chronic liver disease. HDV is a defective RNA agent needing the presence of HBV for its life cycle. HDV is present worldwide, but the distribution pattern is not uniform. Different strains are classified into eight genotypes represented in specific regions and associated with peculiar disease outcome. Two major specific patterns of infection can occur, i.e. co-infection with HDV and HBV or HDV superinfection of a chronic HBV carrier. Co-infection often leads to eradication of both agents, whereas superinfection mostly evolves to HDV chronicity. HDV-associated chronic liver disease (chronic hepatitis D) is characterized by necro-inflammation and relentless deposition of fibrosis, which may, over decades, result in the development of cirrhosis. HDV has a single-stranded, circular RNA genome. The virion is composed of an envelope, provided by the helper HBV and surrounding the RNA genome and the HDV antigen (HDAg). Replication occurs in the hepatocyte nucleus using cellular polymerases and via a rolling circle process, during which the RNA genome is copied into a full-length, complementary RNA. HDV infection can be diagnosed by the presence of antibodies directed against HDAg (anti-HD) and HDV RNA in serum. Treatment involves the administration of pegylated interferon-α and is effective in only about 20% of patients. Liver transplantation is indicated in case of liver failure.

Evolution and diversity of the human hepatitis d virus genome

Human hepatitis delta virus (HDV) is the smallest RNA virus in genome. HDV genome is divided into a viroid-like sequence and a protein-coding sequence which could have originated from different resources and the HDV genome was eventually constituted through RNA recombination. The genome subsequently diversified through accumulation of mutations selected by interactions between the mutated RNA and proteins with host factors to successfully form the infectious virions. Therefore, we propose that the conservation of HDV nucleotide sequence is highly related with its functionality. Genome analysis of known HDV isolates shows that the C-terminal coding sequences of large delta antigen (LDAg) are the highest diversity than other regions of protein-coding sequences but they still retain biological functionality to interact with the heavy chain of clathrin can be selected and maintained. Since viruses interact with many host factors, including escaping the host immune response, how to design a program to predict RNA genome evolution is a great challenging work.

Hepatitis D: Scenario in the Asia-Pacific region

Hepatitis D virus (HDV) infection is present worldwide and affects all age groups. Around 18 million people are estimated to be infected with HDV. An important trend in HDV infection is global decline. HDV prevalence has decreased significantly in Europe since the 1970s and 1980s when it was first reported. The Asia-Pacific region now seems to be where HDV is a major health concern. There is a lack of available data from most of the countries from this region; hence, the true status of HDV cannot be determined. In South Asia, most of the countries have conditions that are favorable for the spread of hepatitis B and other related infections. Countries like Pakistan and Iran have shown an increase in HDV prevalence over a period of time. Other countries and region like China, Turkey, Australia, Japan, India and Taiwan, some of which had very high HDV prevalence in the past, have shown a decline in the incidence, but high prevalence persists in some. Intravenous drug abusers, homosexual men and women, prostitutes, and people on hemodialysis are the groups with very high HDV prevalence.

Pro-205 of large hepatitis delta antigen and Pro-62 of major hepatitis B surface antigen influence the assembly of different genotypes of hepatitis D virus

Hepatitis B surface antigen (HBsAg) is essential for the assembly and infection of hepatitis D virus (HDV). The assembly efficiency of genotype 1 HDV is higher than that of genotype 2, whilst the P62L substitution of major HBsAg further compromises the assembly of genotype 2 and 4 HDV. This study investigated the influence of proline residues in the carboxyl end of the large hepatitis delta antigen (HDAg-L) on the assembly of HDV of different genotypes. Expression vectors containing the HDAg-L gene or full-length HDV genome of genotype 1, 2 or 4 were co-transfected with plasmids expressing HBsAg proteins that bore either proline or leucine residues at position 62. Of the eight HDV genotypes, only genotype 1 has Pro-205 in HDAg-L, whereas genotypes 2 and 4 have Arg-205. The Arg-205 to Pro-205 substitution in HDV-2 and -4 markedly increased the assembly efficiencies of HDAg-L and whole HDV genomes, even in the presence of HBsAg with Leu-62. In contrast, secretion of genotype 1 HDV or HDAg-L was reduced significantly when arginine or alanine replaced Pro-205. When HBsAg contained Pro-62, the influence of Pro-205 on assembly decreased. In conclusion, both Pro-205 of the HDAg-L and Pro-62 of the major HBsAg play critical roles in the assembly of HDV of different genotypes. The presence of Pro-205 in genotype 1 HDV may account for its higher assembly efficiencies and wider distribution.

Hepatitis B virus and hepatitis delta virus genotypes in outbreaks of fulminant hepatitis (Labrea black fever) in the western Brazilian Amazon region

The genotypes of hepatitis B (HBV) and delta (HDV) viruses circulating among fulminant hepatitis cases from the western Amazon Basin of Brazil were characterized in this study. HBV and HDV isolates were obtained from liver samples from 14 patients who developed fulminant hepatitis and died during 1978-1989. HBV DNA and HDV RNA were detected in all samples. Phylogenetic analyses of HDV sequences showed that they all clustered with previously characterized sequences of HDV genotype 3 (HDV-3). HBV genotypes F, A and D were found in 50.0, 28.6 and 21.4 % of cases, respectively. These results confirm the predominance of HDV-3 in South America and its association with the severe form of hepatitis, and the finding of the co-infection of HDV-3 with different genotypes of HBV suggests that the association between HDV-3 and HBV-F is not necessarily causally related to a more severe clinical course of infection.

The fraction of RNA that folds into the correct branched secondary structure determines hepatitis delta virus type 3 RNA editing levels

RNA editing by the host RNA adenosine deaminase ADAR1 at the amber/W site of hepatitis delta virus RNA plays a central role in the viral replication cycle by affecting the balance between viral RNA synthesis and packaging. Previously, we found that HDV genotype III (HDV-3) RNA can form two secondary structures following transcription: an unbranched rod structure, which is characteristic of HDV, and a metastable branched structure that serves as the substrate for editing. The unstable nature of the branched editing substrate structure raised the possibility that structural dynamics of the RNA following transcription could determine the rate at which editing occurs. Here, editing and its control are examined in two HDV-3 isolates, from Peru and Ecuador. Analysis of editing in vitro by ADAR1 indicated that the branched structure formed by RNA derived from the Peruvian isolate is edited more efficiently than that from the Ecuadorian isolate. In contrast, in the context of replication, Peruvian RNA is edited less efficiently than RNA containing Ecuadorian sequences. Computational analyses of RNA folding using the massively parallel genetic algorithm (MPGAfold) indicated that the Peruvian RNA is less likely to form the branched structure required for editing than the Ecuadorian isolate. This difference was confirmed by in vitro transcription of these RNAs. Overall, our data indicate that HDV-3 controls RNA editing levels via (1) the fraction of the RNA that folds, during transcription, into the metastable branched structure required for editing and (2) the efficiency with which ADAR1 edits this branched substrate RNA.

Generation of cytotoxicity against hepatitis delta virus genotypes and quasispecies by epitope modification

BACKGROUND/AIMS

Quasispecies are likely responsible for virus escape from host immune surveillance. The aim of this study was to enhance the immune response against varied sequences within the HDV quasispecies in an attempt to control chronic delta hepatitis.

METHODS

The HLA-A2 restricted peptides spanning aa 43-51 of HDAg and three variant peptides bearing single amino acid substitutions were synthesized. Their immunogenicity and capacity to induce effective CTL responses were studied in HHD-2 mice.

RESULTS

Native HDV epitope produced limited cytotoxic immune response. Two modified HDV peptides (HDV 43-51 1Y; tyrosine substitution in positive 1, and 43-51 3A; alanine substitution in position 3) could enhance not only the binding affinity with HLA-A2.1 molecules but also the immunogenicity. Ex vivo interferon-gamma ELISPOT and CTL assays revealed that the two modified epitopes-induced CTLs had a higher functional avidity and produced stronger cytotoxicity to lyse constitutively HDAg-expressing Hep-G2 cells. Interestingly, the spectrums of the T cell receptor (TCR) cross-reactivity are broadened and response to multiple HDV variants by the enhanced epitopes immunization.

CONCLUSIONS

The modified HDV peptides can enhance the immunogenicity and the induced CTLs can cross-react with multiple HDV variants. Combination with the two enhanced epitopes might be a potential immunotherapeutic agent to control HDV quasispecies in HLA-A2 chronic hepatitis D patients.

The C-terminal sequence of the large hepatitis delta antigen is variable but retains the ability to bind clathrin

BACKGROUND

Hepatitis delta virus (HDV) is a defected RNA virus and requires its encoded large antigen (LDAg) to interact with helper viral proteins (HBsAgs) during assembly. Recently, a study demonstrated a direct binding of the LDAg C-terminus from genotype I HDV to the clathrin heavy chain (CHC), which suggests that this interaction might facilitate HDV assembly. If LDAg binding to clathrin is essential to HDV life cycle, a clathrin box sequence at the C-terminus of LDAg should be conserved across all HDV. However, the C-terminal sequence of LDAg is variable among 43 HDV isolates.

RESULTS

Based on the presence and location of clathrin box at the C-terminus of LDAg from 43 isolates of HDV, we classified them into three groups. Group 1 (13 isolates) and 2 (26 isolates) contain a clathrin box located at amino acids 199-203 and 206-210, respectively, as found in genotype I and genotype II. Group 3 (4 isolates) contains no clathrin box as found in genotype III. CHC binding by three different LDAg (genotype I to III) was then tested by in vivo and in vitro experiments. Transfection of plasmids which encode fusion proteins of EGFP and full-length of LDAg from three genotypes into HuH-7 cells, a human hepatoma cell line, was performed. GFP-pull down assays showed that a full-length of CHC was co-precipitated by EGFP-LDI, -LDII and -LDIII but not by EGFP. Further in vitro studies showed a full-length or fragment (amino acids 1 to 107) of CHC can be pull-down by 13-amino-acid peptides of LDAg from three genotypes of HDV.

CONCLUSION

Both in vivo and in vitro studies showed that CHC can bind to various sequences of LDAg from the three major genotypes of HDV. We therefore suggest that the clathrin-LDAg interaction is essential to the HDV life-cycle and that sequences binding to clathrin are evolutionarily selected, but nonetheless show the diversity across different HDV genotypes.

Molecular epidemiology of hepatitis delta virus (HDV) in Iran: a preliminary report

To identify hepatitis delta virus (HDV) genetic variability and its circulating genotypes amongst infected Iranian patients, 25 patients with positive anti-HDV status from different parts of Iran were enrolled in this cross-sectional study. A portion of the HDV delta antigen was amplified, sequenced, and subjected to molecular and phylogenetic analysis. Clinical features and virological markers were evaluated. HDV RNA could be detected in 88% of anti-HDV positive cases (22 patients) with chronic hepatitis B virus (HBV) infection and liver cirrhosis. Phylogenetic analysis revealed that all Iranian patients were infected by genotype I (clade 1) of HDV, supported by a high bootstrap value (100%, 1,000 replicates). All HDV-positive patients were coinfected with genotype D1 of HBV. No significant association was determined between demographic, clinical, and virological variables in the population studied. In conclusion, the present molecular epidemiology survey reveals that clade 1 of HDV is predominant among coinfected HBV patients in Iran.

Hepatitis D and B virus genotypes in chronically infected patients from the Eastern Amazon Basin

Hepatitis D virus (HDV) is a defective hepatotropic virus whose infectivity is dependent on hepatitis B virus (HBV). HDV super- or co-infection leads to an increased risk of fulminant hepatitis or progression to severe chronic liver disease in HBV infected patients. The Brazilian Amazon Basin has been reported to be endemic for HBV and HDV, especially in the Western Amazon Basin. In this region, HDV infection is frequently associated with acute fulminant hepatitis with characteristic histologic features. HDV is classified into seven major clades (HDV-1 to HDV-7) and HBV is subdivided into eight genotypes (A-H). HDV and HBV genotypes have been shown to have a distinct geographic distribution. The aim of this study was to determine the HBV and HDV genotypes harbored by chronically infected patients from the Eastern Amazon Basin, Brazil. We studied 17 serum samples from HBV and HDV chronically infected patients admitted to a large public hospital (Santa Casa de Misericórdia) at Belém, state of Pará, Brazil, between 1994 and 2002. HDV-3 and HBV genotype A (subtype adw2) have been identified in all cases, in contrast to previous studies from other regions of the Amazon, where HBV genotype F has been found co-infecting patients that harbored HDV-3. The HDV-3/HBV-A co-infection suggests that there is not a specific interaction between HBV and HDV genotypes, and co-infection might merely reflect the most frequent genotypes found in a particular geographic area. The analysis of the carboxy-terminal region of the large hepatitis D antigen (L-HDAg), which interacts with the hepatitis B surface antigen (HBsAg) and is essential for HDV assembly, showed some diversity between the different isolates from the Eastern Amazon. This diversity is not observed among HDV-3 sequences from other South American regions.

Acute liver failure: Summary of a workshop

Acute liver failure (ALF) is a rare but challenging clinical syndrome with multiple causes; a specific etiology cannot be identified in 15% of adult and 50% of pediatric cases. The course of ALF is variable and the mortality rate is high. Liver transplantation is the only therapy of proven benefit, but the rapidity of progression and the variable course of ALF limit its use. Currently in the United States, spontaneous survival occurs in approximately 45%, liver transplantation in 25%, and death without transplantation in 30% of adults with ALF. Higher rates of spontaneous recovery (56%) and transplantation (31%) with lower rates of death (13%) occur in children. The outcome of ALF varies by etiology, favorable prognoses being found with acetaminophen overdose, hepatitis A, and ischemia (approximately 60% spontaneous survival), and poor prognoses with drug-induced ALF, hepatitis B, and indeterminate cases (approximately 25% spontaneous survival). Excellent intensive care is critical in management of patients with ALF. Nonspecific therapies are of unproven benefit. Future possible therapeutic approaches include N-acetylcysteine, hypothermia, liver assist devices, and hepatocyte transplantation. Advances in stem cell research may allow provision of cells for bioartificial liver support. ALF presents many challenging opportunities in both clinical and basic research.

Hepatitis B surface antigen levels and sequences of natural hepatitis B virus variants influence the assembly and secretion of hepatitis d virus

Various domains of hepatitis B surface antigen (HBsAg) are essential for the assembly and secretion of hepatitis D virus (HDV). This study investigated the influences of the levels and sequences of HBsAg of naturally occurring HBV variants on the assembly and secretion of HDV. Six hepatitis B virus (HBV)-producing plasmids (three genotype B and three genotype C) and six HBsAg expression plasmids that expressed various HBsAg levels were constructed from the sera of HDV-infected patients. These plasmids were cotransfected with six expression plasmids of HDV of genotype 1, 2, or 4 into the Huh-7 hepatoma cell line. Serum HBsAg and HBV DNA levels were correlated with HDV RNA levels and outcomes of chronic hepatitis D (CHD) patients. The secretion of genotype 1, 2, or 4 HDV generally correlated with HBsAg levels but not with HBV genotypes or HBV DNA levels. Swapping and residue mutagenesis experiments of HBsAg-coding sequences revealed that the residue Pro-62 in the cytosolic domain-I affects the assembly and secretion of genotype 2 and 4 HDV and not those of genotype 1. The pre-S2 N-terminal deletion HBV mutant adversely affects secretion of the three HDV genotypes. In patients, serum HDV RNA levels correlated with HBsAg levels but not with HBV DNA levels. Viremia of HDV or HBV correlated with poor outcomes. In conclusion, the assembly and secretion of HDV were influenced by the amounts and sequences of HBsAg. For an effective treatment of CHD, reduction of HBsAg production in addition to the suppression of HBV and HDV replication might be crucial.

Current prevalence of hepatitis delta virus (HDV) infection and the range of HDV genotypes in Lebanon

Recently the prevalence of hepatitis B virus (HBV) genotypes and the association between these genotypes and the clinical status of HBV-infected patients were recently investigated in the Lebanese population. The aim of the additional study reported here was to determine the current prevalence of hepatitis delta virus (HDV) infection and the range of HDV genotypes in this Lebanese population. Two hundred and fifty-eight HBsAg-positive patients (107 asymptomatic blood donors, 92 with chronic hepatitis, 24 with cirrhosis, 15 with hepatocellular carcinoma, 20 patients on haemodialysis) from ten medical centers in Lebanon were tested for antibody to hepatitis D virus (anti-HDV). Those testing positive were analysed further for HDV-RNA and for genotyping by reverse transcriptase-polymerase chain reaction (RT-PCR) and restriction fragment length polymorphism (RFLP). Three samples (1.2%) were anti-HDV positive and out of these, only one was HDV-RNA positive (0.6%) and was analysed as HDV genotype I. Our results point to a low endemicity of HDV in the Lebanese population which is in sharp contrast to data reported from Lebanon 20 years ago and to the situation in neighbouring Arab and non-Arab countries in the Mediterranean region. HDV genotype I seems to be the predominant genotype in Lebanon and the Middle East.