Hepatitis delta virus genotypes I and II cocirculate in an endemic area of Yakutia, Russia.
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Currently, three genotypes of hepatitis delta virus (HDV) are described. The most common, genotype I, has a worldwide distribution; in contrast, genotype II has been found previously only in Japan and Taiwan, while genotype III is found exclusively in South America. Considering the high prevalence of HDV in Northern Siberia (Russia), restriction fragment length polymorphism (RFLP) was used to analyse HDV genotypes from 29 infected patients living in Yakutia. Of these isolates, 11 were characterized by partial nucleotide sequencing and two isolates were completely sequenced. Phylogenetic inference methods included maximum parsimony, maximum likelihood and distance analyses. A restriction pattern consistent with HDV genotype I was found in 14 samples, while the remaining 15 showed a different restriction pattern, inconsistent with any known genotype. Five Yakutian HDV isolates with the type I restriction pattern were sequenced and confirmed to be affiliated with genotype I, although the phylogenetic results indicate that they were heterogeneous and did not cluster together. Sequencing of eight isolates with the new RFLP pattern revealed that these isolates were most closely related to HDV genotype II. In contrast to HDV Yakutian genotype I sequences, all of these type II sequences formed a well-defined clade on phylogenetic trees. Comparison of clinical presentations during hospitalization between patients infected with HDV type I (n=14) and type II (n=15) did not reveal any differences in the severity of infection. These data indicate that the distribution of genotype II is not restricted to Taiwan or Japan, but spreads over Northern Asia, appearing in the native population of Yakutia. Type II Yakutian strains appeared to form a well-defined subclade and could be associated with severe chronic hepatitis in this area. (+info)
Sonography of diffuse liver disease.
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Sonography is often the first imaging procedure performed in the evaluation of individuals with suspected liver disease. Evaluation for biliary dilatation is always performed, because bile duct obstruction can cause abnormal liver test results, raising the suspicion of liver disease. Ultrasound is a useful but imperfect tool in evaluating diffuse liver disease. We discuss the uses and limitations of sonography in evaluating parenchymal liver disease. Sonography can show hepatomegaly, fatty infiltration of the liver, and cirrhosis, all with good but imperfect sensitivity and specificity. Sonography is of limited usefulness in acute hepatitis. Increased parenchymal echogenicity is a reliable criterion for diagnosing fatty liver. Cirrhosis can be diagnosed in the correct clinical setting when the following are present: a nodular liver surface, decreased right lobe-caudate lobe ratio, and indirect evidence of portal hypertension (collateral vessels and splenomegaly). Ultrasound plays an important role in the imaging of conditions and procedures common in patients with diffuse liver disease. (+info)
Chronic hepatitis delta virus infection with genotype IIb variant is correlated with progressive liver disease.
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We determined the sequence of the hepatitis delta virus (HDV) genome in 40 Japanese patients, most of whom were from the Miyako Islands, Okinawa, Japan. Consensus sequences from 33 HDV full genomes out of a total of 40 patients were determined by directly sequencing four partially overlapping PCR products. Phylogenetic tree analysis classified these 33 complete HDV genomes as HDV genotype I (two patients), genotype IIa (one patient) and genotype IIb (30 patients). Among the 30 genotype IIb patients, there were two clusters of genetic variants. One group consisted of six isolates showing significant homology with genotype IIb, previously reported from Taiwan. The other group consisted of 24 isolates, whose sequences formed a new genetic subgroup (genotype IIb-Miyako; IIb-M). When the genetic structures were compared in detail between IIb and IIb-M, characteristic variations were found in the C-terminal sequence of the large delta antigen-conferring packaging signal as well as the RNA editing site. Determination of subclasses of genotype IIb in a total of 37 patients, including seven HDV patients whose partial HDV sequence was determined, revealed eight patients with IIb and 29 patients with IIb-M. Although there was no significant difference in the clinical background or virological state of hepatitis B virus between these two groups, patients with genotype IIb-M showed greater progression of chronic hepatitis and cirrhosis than those with genotype IIb (P=0.0009). These data indicate the existence of a genetic subgroup of HDV genotype IIb, which is associated with different clinical characteristics and which could be related to genetic variations in functionally important parts of the HDV genome. (+info)
Epidemiology of viruses causing chronic hepatitis among populations from the Amazon Basin and related ecosystems.
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On the last twenty years, viral hepatitis has emerged as a serious problem in almost all the Amerindian communities studied in the Amazon Basin and in other Amazon-related ecological systems from the North and Center of South America. Studies performed on communities from Bolivia, Brazil, Colombia, Peru and Venezuela have shown a high endemicity of the hepatitis B virus (HBV) infection all over the region, which is frequently associated to a high prevalence of infection by hepatitis D virus among the chronic HBV carriers. Circulation of both agents responds mainly to horizontal virus transmission during childhood through mechanisms that are not fully understood. By contrast, infection by hepatitis C virus (HCV), which is present in all the urban areas of South America, is still very uncommon among them. At the moment, there is not data enough to evaluate properly the true incidence that such endemicity may have on the health of the populations affected. Since viral transmission might be operated by mechanisms that could not be acting in other areas of the World, it seems essential to investigate such mechanisms and to prevent the introduction of HCV into these populations, which consequences for health could be very serious. (+info)
Quantitation of the level of hepatitis delta virus RNA in serum, by real-time polymerase chain reaction--and its possible correlation with the clinical stage of liver disease.
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Some hepatitis B virus (HBV) carriers with chronic hepatitis delta virus (HDV) superinfection show progressive chronic hepatitis, whereas others show no apparent signs of liver disease. In the present study, we established a sensitive method for the quantitation of the level of HDV RNA in serum on the basis of real-time reverse-transcription polymerase chain reaction (RT-PCR), to clarify the role that the level of HDV RNA in serum plays in the diverse natural course of clinical manifestation. In 48 subjects who were positive for hepatitis B surface antigen and for anti-hepatitis delta antibody, the levels of HDV RNA in serum were quantitated by RT-PCR. The levels of HBV DNA in serum were determined by a transcription-mediated amplification assay. The levels of HDV RNA in serum of subjects with chronic hepatitis and of subjects with liver cirrhosis were significantly higher than those in asymptomatic carrier subjects. The levels of HBV DNA in serum did not differ significantly among these 3 groups. In conclusion, HDV RNA quantification by real-time RT-PCR is possibly a useful tool for understanding the pathophysiology of HDV infection. (+info)
Pathological changes and clinical manifestations of 1020 children with liver diseases confirmed by biopsy.
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BACKGROUND: Liver biopsy plays an important role in accurate diagnosis of various liver diseases in children and liver damages caused by systemic illnesses. This study was designed to evaluate the value of liver biopsy in diagnosis of liver diseases in children and explore the relationship between their pathological changes and clinical manifestations. METHODS: One-second liver biopsy was performed in 1023 pediatric patients with liver diseases at our department from 1983 to 2000. Diagnosis of viral hepatitis was based on the diagnostic criteria formulated by the Chinese Society of Infectious and Parasitic Diseases in 1995. Inflammatory changes of the liver were graded from 0 to 4 (G0-4). RESULTS: Liver biopsy was performed successfully in 1020 patients including 135 infants and young children, of whom 90% were hospitalized patients with chronic liver diseases. Hepatitis virus was the leading cause for chronic liver diseases, among which hepatitis B was detected in 75.4% of the patients. Sixty-nine patients showed liver impairment induced by disorders relevant to that metabolism, Wilson's disease, and glycogen storage disease. Liver inflammatory injury (+info)
Identification of novel HLA-A*0201-restricted CD8+ T-cell epitopes on hepatitis delta virus.
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Hepatitis delta virus (HDV) superinfection causes a poor prognosis in hepatitis B virus-infected patients and effective therapy is lacking. Cytotoxic T-lymphocyte (CTL) responses play an important role in the pathogenesis of chronic viral hepatitis; however, the CD8+ T-cell epitopes of HDV have never been defined. Potential HLA-A*0201-restricted HDV peptides were selected from the SYFPEITHI database and screened by T2 cell-stabilization assay. HLA-A*0201 transgenic mice on a C57BL/6 background were injected intramuscularly with an HDV DNA vaccine. Splenocytes were stained directly ex vivo with HLA-A*0201-peptide tetramers after immunization. Epitope-specific CTL responses were confirmed by cytotoxic assays. HLA-A2, chronically infected HDV patients were also enrolled, to assess the existence of HDV-specific CD8+ T cells, based on findings in animals. Following HDV DNA vaccination, nearly 0.9 % of the total splenic CD8+ T cells were specific for peptides HDV 26-34 and HDV 43-51 in HLA-A*0201 transgenic mice, which was significantly higher than the number found in non-transgenic mice or in transgenic mice that had been immunized with control plasmid. HDV 26-34- and 43-51-specific CTL lines were able to produce CTL responses to each peptide. Interestingly, HDV 26-34- and HDV 43-51-specific CD8+ T cells were also detectable in two chronically infected HDV patients in the absence of active HDV replication. In conclusion, HDV 26-34 and 43-51 are novel HLA-A*0201-restricted CTL epitopes on genotype I HDV. HDV 26-34- and 43-51-specific CTLs have been detected in chronic hepatitis delta patients without active disease. Evoking CTL responses to HDV may be an alternative approach to controlling HDV viraemia in patients with chronic hepatitis delta. (+info)
"Defective" mutations of hepatitis D viruses in chronic hepatitis D patients.
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AIM: To verify whether "defective" mutations existed in hepatitis D virus (HDV). METHODS: Hepatitis delta antigen (HDAg)-coding sequences were amplified using Pfu DNA polymerases with proof-reading activities from sera of five patients with chronic hepatitis D. Multiple colonies were sequenced for each patient. Pfu analyzed a total of 270 HDV clones. Three representative defective HDV clones were constructed in expression plasmids and transfected into a human hepatoma cell line. Cellular proteins were extracted and analyzed by Western blot. RESULTS: Four of five cases (80%) showed defective HDV genomes in their sera. The percentage of defective genomes was 3.7% (10/270). The majority (90%) of the defective mutations were insertions or deletions that resulted in frameshift and abnormal stop translation of the HDAg. The predicted mutated HDAg ranged from 45 amino acids to >214 amino acids in length. Various domains of HDAg associated with viral replication or packaging were affected in different HDV isolates. Western blot analysis showed defected HDAg in predicted positions. CONCLUSION: "Defective" viruses do exist in chronic HDV infected patients, but represented as minor strains. The clinical significance of the "defected" HDV needs further study to evaluate. (+info)