Severity of liver disease with different hepatitis C viral clones

Molecular Targets in Inhibition of Hepatitis C Virus Replication

Hepatitis C virus (HCV) is the major cause of transfusion-associated hepatitis and accounts for a significant proportion of hepatitis cases worldwide. Most, if not all, infections become persistent and about 60% of cases develop chronic liver disease with various outcomes ranging from an asymptomatic carrier state to chronic active hepatitis and liver cirrhosis, which is strongly associated with the development of hepatocellular carcinoma. Since the initial cloning of the viral genome in 1989, our knowledge of the molecular biology of HCV has increased rapidly and led to the identification of several potential targets for antiviral intervention. In contrast, the low replication of the virus in cell culture, the lack of convenient animal models and the high genome variability present major challenges for drug development. This review will describe candidate drug targets and summarize ‘classical’ and ‘novel’ approaches currently being pursued to develop efficient HCV-specific therapies.

HCV genome-wide genetic analyses in context of disease progression and hepatocellular carcinoma

Hepatitis C virus (HCV) is a major cause of hepatitis and hepatocellular carcinoma (HCC) world-wide. Most HCV patients have relatively stable disease, but approximately 25% have progressive disease that often terminates in liver failure or HCC. HCV is highly variable genetically, with seven genotypes and multiple subtypes per genotype. This variation affects HCV's sensitivity to antiviral therapy and has been implicated to contribute to differences in disease. We sequenced the complete viral coding capacity for 107 HCV genotype 1 isolates to determine whether genetic variation between independent HCV isolates is associated with the rate of disease progression or development of HCC. Consensus sequences were determined by sequencing RT-PCR products from serum or plasma. Positions of amino acid conservation, amino acid diversity patterns, selection pressures, and genome-wide patterns of amino acid covariance were assessed in context of the clinical phenotypes. A few positions were found where the amino acid distributions or degree of positive selection differed between in the HCC and cirrhotic sequences. All other assessments of viral genetic variation and HCC failed to yield significant associations. Sequences from patients with slow disease progression were under a greater degree of positive selection than sequences from rapid progressors, but all other analyses comparing HCV from rapid and slow disease progressors were statistically insignificant. The failure to observe distinct sequence differences associated with disease progression or HCC employing methods that previously revealed strong associations with the outcome of interferon α-based therapy implies that variable ability of HCV to modulate interferon responses is not a dominant cause for differential pathology among HCV patients. This lack of significant associations also implies that host and/or environmental factors are the major causes of differential disease presentation in HCV patients.

Impact of HCV genetic differences on pathobiology of disease

Multiple HCV genotypes have been isolated worldwide. Genotype seems to be involved in the main pathological aspects of HCV infection. Insulin resistance, steatosis and progression toward cirrhosis, fibrosis and hepatocellular carcinoma establish and develop following genotype-specific mechanisms. Moreover genotype influences pharmacological treatment in term of dose and duration. Pathways involved in cell proliferation, apoptosis, lipid metabolism, insulin and interferon signaling are impaired to a different extent among genotypes, leading to distinct pathological settings. Genotype 1 is associated with a more aggressive disease with increased insulin resistance, worst response to therapy, higher risk of cirrhosis and hepatocellular carcinoma development, while genotype 3 is associated with increased steatosis and fibrosis. The identification and characterization of HCV types and subtypes provides insight into the different outcome of HCV infection and responsiveness to therapy. In the present article, we focused on the pathogenicity of HCV genotypes and their effect on disease progression and treatment.

Prevalence of hepatitis C virus (HCV) genotypes among positive UAE patients

A molecular study was conducted to investigate the prevalence of Hepatitis C virus genotypes in HCV infected population of UAE. 67 HCV seropositive samples were collected from different health care centres. Quantitative analysis of these samples using PCR resulted in 67 positive samples. The PCR positive samples were subjected to genotyping using the method described by Simmonds et al. (J Gen Virol 74: 2391-2399, 1993). HCV genotype 4 was the predominant genotype (46.2%) followed by genotype 3a (23.8%) and 1a (15%). The predominant genotype among the female patients was genotype 4 (65.6%), while genotype 3a was the predominant among the male patients (42.8%). The predominance of HCV genotype 4 in our population confirms the predominance of HCV genotype 4 in UAE and most of the Arab countries in the Middle East. Implications of genotyping for clinical outcome of HCV infection, response to treatment as well as for vaccine development are discussed.

An overview about hepatitis C: a devastating virus

Hepatitis C (HCV) is the disease that has affected around 200 million people globally. HCV is a life threatening human pathogen, not only because of its high prevalence and worldwide burden but also because of the potentially serious complications of persistent HCV infection. Chronicity of the disease leads to cirrhosis, hepatocellular carcinoma and end-stage liver disease. HCV positive hepatocytes vary between less than 5% and up to 100%, indicating the high rate of replication of viral RNA. HCV has a very high mutational rate that enables it to escape the immune system. Viral diversity has two levels; the genotypes and Quasiaspecies. Major HCV genotypes constitute genotype 1, 2, 3, 4, 5 and 6 while more than 50 subtypes are known. All HCV genotypes have their particular patterns of geographical distribution and a slight drift in viral population has been observed in some parts of the globe.

Natural history of hepatic fibrosis progression in chronic hepatitis C virus infection in India

BACKGROUND AND AIM

The rate of fibrosis progression per year can predict the time for the development of cirrhosis in chronic hepatitis C (CHC). We assessed the rate of fibrosis progression and the predictors of disease severity in Indian CHC patients.

METHODS

Of the 355 treatment-naïve, histologically-proven CHC patients, the precise duration of infection (from the time of exposure to HCV until liver biopsy) could be determined in 213 patients (age = 41.6 +/- 14.7 years, male : female = 139 : 74, genotype 3 = 75%). The rate of fibrosis progression per year was calculated. The correlation of the advanced degree of fibrosis and age, duration of infection, age at the onset of infection, sex, mode of infection, hepatitis C virus (HCV) genotype, histological activity index (HAI), and the presence of diabetes mellitus were studied.

RESULTS

The median rate of fibrosis progression per year was 0.25 (0.0-1.5) fibrosis units. The fibrosis progression rate was higher in patients who acquired infection at > 30 years of age, those < 30 years (0.33 vs 0.15; P < 0.001), and those who acquired HCV infection with a history of blood transfusion than with other modes of transmission (0.25 vs 0.19; P = 0.04). The median time to progress to cirrhosis was 16 years. The multivariate analysis found that the HAI score (odds ratio [OR]= 14.03; P < 0.001) and the duration of infection > 10 years (OR = 4.83; P < 0.001) correlated with severe liver disease (fibrosis > or = 3).

CONCLUSION

The median rate of fibrosis progression per year in Indian CHC patients is 0.25 fibrosis units. A higher HAI and longer duration of infection are associated with a significant risk of advanced liver disease, and merit early therapeutic interventions.

Prevalence of hepatitis C virus (HCV) genotypes in Balochistan

A molecular study was conducted to investigate the prevalence of Hepatitis C virus genotypes in HCV infected population of Balochistan. Forty HCV seropositive samples belonging to seven different locations of Balochistan were collected from different health care centres. Qualitative analysis of these samples using PCR resulted in 28 positive samples. The PCR positive samples were subjected to genotyping using the method described by Ohno et al (J Clin Microbiol 35:201-202, 1997) with minor modifications. Genotyping of 28 samples revealed three different genotypes including 3a, 3b and 1a. The most prevalent genotype was 3a with rate of 50% followed by genotype 3b and 1a, respectively. Nine samples remained untyped, suggesting the need of further investigation of genotypes in this region. It has been proposed that sequencing of these samples may be helpful to unreveal these genotypes and further epidemiology of HCV genotypes. Further more, extensive and large scale studies are needed to understand the epidemiology of HCV genotypes, as no such study has been carried in this province.

Cutting the gordian knot-development and biological relevance of hepatitis C virus cell culture systems

Worldwide approximately 180 million people are chronically infected with hepatitis C virus (HCV). HCV isolates exhibit extensive genetic heterogeneity and have been grouped in six genotypes and various subtypes. Additionally, several naturally occurring intergenotypic recombinants have been described. Research on the viral life cycle, efficient therapeutics, and a vaccine has been hampered by the absence of suitable cell culture systems. The first system permitting studies of the full viral life cycle was intrahepatic transfection of RNA transcripts of HCV consensus complementary DNA (cDNA) clones into chimpanzees. However, such full-length clones were not infectious in vitro. The development of the replicon system and HCV pseudo-particles allowed in vitro studies of certain aspects of the viral life cycle, RNA replication, and viral entry, respectively. Identification of the genotype 2 isolate JFH1, which for unknown reasons showed an exceptional replication capability and resulted in formation of infectious viral particles in the human hepatoma cell line Huh7, led in 2005 to the development of the first full viral life cycle in vitro systems. JFH1-based systems now enable in vitro studies of the function of viral proteins, their interaction with each other and host proteins, new antivirals, and neutralizing antibodies in the context of the full viral life cycle. However, several challenges remain, including development of cell culture systems for all major HCV genotypes and identification of other susceptible cell lines.

Histopathology of chronic hepatitis C in relation to virus genotype

BACKGROUND/AIM

The natural history of hepatitis C virus (HCV) infection is variable and the factors determining the course of the illness are unclear. There are geographical variations in the distribution of different HCV genotypes, and some of them are related to the specific infection routes. Regarding our country, the dominant genotype is genotype 1b. It is unclear and still remains a question whether the distinct histopathological manifestations are related to the particular genotypes of HCV. Thus, the aim of this study was to determine whether the distinct histopathological manifestations of HCV infection might be in relation to the individual virus genotype.

METHODS

In this study we examined 126 patients with chronic HCV infection regarding the histopathological features, demographic data, and virus genotype. The observed groups of patients were predominantly infected with HCV genotypes 1b and 3a.

RESULTS

In this study we found that the patients infected with HCV genotype 1b had more frequently moderate or severe necroinflammatory activity of the disease, significantly higher grading score as compared with other genotypes (p < 0.0001). A higher degree of fibrosis was, also, more common in the patients infected with genotype 1b of HCV as compared with other genotypes (p < 0.05). There were no significant correlations between the necroinflammatory activity of the disease and the stage of fibrosis in 1b, 4 and mixed genotypes.

CONCLUSION

The present data support the hypothesis that distinct genotypes of HCV are associated with the particular histopathological manifestation of the disease.

Hepatitis C virus genotype 3 predominates in North and Central India and is associated with significant histopathologic liver disease

Hepatitis C virus (HCV) genotypes help to tailor the treatment response, but their influence on the disease severity and association with hepatic steatosis is not well understood. The prevalence of HCV genotypes and their correlation with the histopathological severity of liver disease and steatosis in Indian patients were studied. HCV-RNA and genotyping was carried out in 398 patients with chronic hepatitis C. Liver biopsy was available in 292 (73.4%) patients. The severity of liver disease was graded on the basis of the histological activity index and the stage of hepatic fibrosis. The patients were categorized as having mild (histological activity index < or =5 and/or fibrosis < or =2) or severe (histological activity index > or =6 and/or fibrosis > or =3) liver disease. Steatosis was graded in 106 patients as 0 (no steatosis), 1 (<33% of hepatocytes affected), 2 (33%-66% of hepatocytes affected), or 3 (>66% of hepatocytes affected). HCV genotype 3 was detected in 80.2% patients (3a:24.4%, 3b:3.3%, 3c:0.5%, 3a/3b:36.7%, and un-subtypable 3:15.3%), genotype 1 in 13.1% (1a:3%, 1b:5.5%, 1a/1b:0.3%, and un-subtypable 1:4.3%), genotype 4 in 3% patients (4a:1.5%, 4b:0.3%, 4a/4c:0.5%, and un-subtypable 4:0.8%), 2 in 2.5% and mixed genotypes (more than one genotype) in 1.3% of patients. The median histological activity index and fibrosis scores were: 5 and 2 in genotype 1; 4 and 2 in genotype 2; 5 and 2 in genotype 3; 7 and 3 in genotype 4; and 5 and 2 in mixed genotypes, respectively. Severe liver disease was present in 17 of 38 (45%) with genotype 1; in 1 of 3 (33%) with genotype 2; in 128 of 236 (54%) with genotype 3; 7 of 10 (70%) with genotype 4; and in 1 of 4 (25%) with mixed genotype. Hepatic steatosis grade > or =2 was found in 28.1% of genotype 3; 23.5% of genotype 1; 20% of genotype 4; and in none of genotype 2 and mixed genotypes. In conclusion, genotype 3 is the most prevalent genotype in patients with chronic hepatitis C in North and Central India and this is associated with significant hepatic steatosis and fibrosis.

Prevalence of hepatitis C virus infection and HCV genotypes among hemophiliacs in the State of Bahia, Northeastern Brazil: analysis of serological and virological parameters

The objective of the present study was to analyze HCV serological and virological parameters from hemophiliacs in the State of Bahia. Anti-HCV was investigated by ELISA in a cohort of 268 hemophiliacs A/B who were followed-up in a reference unit for hemotherapy in the State of Bahia. HCV viremia and genotypes were also determined from a subset of 66 anti-HCV seropositive hemophiliacs. Seroprevalence among hemophiliacs was 42.2% (95% CI 36.5-48.1) and was significantly higher (p<0.05) according to age > or =10 years, presence of factor VIII/IX inhibitory antibodies and other infection markers. None of the hemophiliacs less than 5 years of age were anti-HCV seropositive. Viremia was detectable in 77.3% (51/66). HCV genotype 1 (74%) was the most prevalent followed by genotype 3 (22%) and genotype 2 (4%). Our results indicate that HCV prevalence is still high among hemophiliacs, although HCV transmission was not observed in young hemophiliacs.

Genotypic variability of hepatitis viruses associated with chronic infection and the development of hepatocellular carcinoma

At least five hepatitis viruses are known to date. Infection by enterically transmitted viruses (HAV and HEV) is generally benign compared with the disease caused by parenterally transmitted viruses (HBV, HCV, and HDV). Chronic infection by HBV is common and may evolve to cirrhosis and hepatocellular carcinoma (HCC). Eight HBV genotypes (A-H) have been described, with the South American genotype F being the most divergent. Seven clades of HDV have been described; among them, the South American genotype III is associated to a high frequency of fulminant hepatitis. HCV infection leads to a high rate of chronicity and HCC. From the six HCV genotypes, infection with genotype 1 might have the worst prognostic. Chronic infection by HCV and HBV is the major risk factor for HCC, which occurs, in the majority of the cases, as a consequence of cirrhosis. However, there is growing evidence that some HBV and HCV proteins might contribute to the generation of HCC. Some HBV and HCV variants and specific mutations within the viral genomes might be more frequently associated with the evolution to HCC. Although more studies are needed, emerging evidence indicates that it might be important to address the genetic variability of these viruses and their contribution to the development of HCC.

Evaluation of a prototype HCV NS5b assay for typing strains of hepatitis C virus isolated from Tunisian haemodialysis patients

Hepatitis C virus (HCV) strains isolated from 68 haemodialysis Tunisian patients exhibiting chronic infection were genotyped targeting the NS5b region of the HCV genome using a prototype assay developed by Bayer HealthCare-Diagnostics (TRUGENE NS5b HCV). The overall results were compared to those obtained with another assay of the same company based on sequencing of the 5' non-coding region (TRUGENE HCV 5'NC genotyping kit). All strains could be typed by the 5'NC typing kit, but only 62 (91; 2%) by the NS5b prototype assay. All the 62 strains typed by both methods exhibited the same pattern at the type level: 57 were type 1, 3 were type 2, and 2 were type 4. At the subtype level, eight strains that gave undetermined results by the 5'NC kit were successfully typed by the NS5b kit; eight additional strains exhibited discrepant results. The overall agreement between the two assays was 74.2% at the subtype level. In conclusion, the NS5b region appears to be much more accurate than the 5'NC region to subtype HCV strains, especially in those isolated from patients attending haemodialysis centres where the subtype distribution suggests frequent nosocomial transmissions.

Development and application of a mixed microarray in detection of genes of HBV and HCV

AIM: To develop a DNA microarray to detect hepatitis virus B (HBV) DNA, hepatitis virus C (HCV) RNA, HBV YMDD mutant and HCV genotype simultaneously. At the same time, the chip was compared with other techniques to evaluate its prospect in clinical application.

METHODS: A set of probes was designed to detect HBV DNA, HCV RNA, HBV YMDD mutant and HCV genotype. The probes were synthesized by DNA synthesizer. The microarray was prepared by spotting the probes onto the specially treated glass sliders. Serum samples were collected from inpatients and outpatients at the Department of Infectious Diseases, the Third Affiliated Hospital of Zhongshan University. Among the samples, 20 were comfirmed HBV DNA positive by fluorescent quantitation PCR, 20 were HCV RNA positive, 20 were comfirmed YMDD mutant by mismatched PCR, 10 were HBV DNA and HCV RNA negative. HBV DNA and HCV RNA were extracted from the serum, then amplified by asymmetric PCR or RT-PCR in the presence of sense fluorescein labeled primers. The products of HBV YMDD and HCV NS-5 were purified and sequenced. Following the hybridization of amplified products on the microarrays, detection was carried out by the fluorescence scanner. The detection results were obtained by analyzing the intensity and ratio of the fluorescence signals using image analysis software.

RESULTS: For the HBV DNA positive samples and HCV RNA positive samples, an intensive signal was observed at the point of corresponding probes on the microarrays. In detection of YMDD mutant, the coincident rate of the microarray and the mismatched PCR was 75%, the coincident rate of microarray and sequencing was 95%. In detection of HCV genotype, the coincident rate of microarray and sequencing was 75%.

CONCLUSION: The technology of microarray appears to be versatile, with a great sensitivity and specifity in detection of HBV and HCV. Furthermore, it can find co-infection of different virus strains. But it has some false negative rate and false positive rate in HCV genotyping.

Managing occupational risks for hepatitis C transmission in the health care setting

Hepatitis C virus (HCV) infection is a significant contemporary health problem in the United States and elsewhere. Because it is primarily transmitted via blood, hepatitis C infection presents risks for both nosocomial transmission to patients and occupational spread to health care workers. Recent insights into the pathogenesis, immunopathogenesis, natural history, and treatment of infection caused by this unique flavivirus provide a rationale for the use of new strategies for managing occupational hepatitis C infections when they occur. This article reviews this developing information. Recently published data demonstrate success rates in the treatment of "acute hepatitis C syndrome" that approach 100\%, and although these studies are not directly applicable to all occupational infections, they may provide important clues to optimal management strategies. In addition, the article delineates approaches to the prevention of occupational exposures and also addresses the difficult issue of managing HCV-infected health care providers. The article summarizes currently available data about the nosocomial epidemiology of HCV infection and the magnitude of risk and discusses several alternatives for managing exposure and infection. No evidence supports the use of immediate postexposure prophylaxis with immunoglobulin, immunomodulators, or antiviral agents. Based on the very limited data available, the watchful waiting and preemptive therapy strategies described in detail in this article represent reasonable interim approaches to the complex problem of managing occupational HCV infections, at least until more definitive data are obtained.

Distribution of the different genotypes of HCV among patients attending a tertiary care hospital in south India

BACKGROUND

Genotyping of the hepatitis C virus (HCV) and assessment of viral load is important for designing therapeutic strategies and region specific diagnostic assays.

OBJECTIVES

To determine the distribution of HCV genotypes among patients attending a tertiary care hospital in south India, and to correlate this with viral load.

STUDY DESIGN

Ninety HCV RNA positive patients were recruited for the study. HCV genotyping was carried out using type-specific primers from the core region of the viral genome [J. Clin. Microbiol. 35 (1997) 201]. Viral load estimations were carried out using the Amplicor HCV Monitor (Versions 1.5 and 2, Roche Diagnostics, Branchburg, NJ, USA). Clinical details were elicited from patients' hospital records.

RESULTS

Genotype 3 was detected most frequently (62.2%) followed by infection with HCV genotype 1 (18.8%). There was no significant difference seen in alanine aminotransferase (ALT) values between the two genotypes. Genotype 1 was associated with a significantly higher viral load as compared with genotype 3 (P=0.001). Parenteral transmission accounted for 61% of all infection caused. Infection with genotype 1 was significantly associated with a history of haemodialysis (P=0.01). Genotype 3 was detected more frequently in patients from east India, as compared with its detection in patients from south India (P=0.004). Similarly, genotype 1 was detected with greater frequency in individuals from south India as compared with patients from east India (P=0.004). The concordance between Ohno's genotyping assay and nucleotide sequencing, for genotypes 1 and 3, was 75%.

CONCLUSIONS

HCV genotypes 1 and 3 accounted for 81% of HCV infections in patients from this geographical region. HCV genotype distribution showed regional differences and genotype 1 was associated with higher viral loads. Parenteral transmission was the major route for acquisition of HCV infection. Ohno's type-specific primer based genotyping assay can be used for distinguishing between HCV genotype 1 and non-1 HCV genotypes in laboratories that do not possess nucleotide sequencing facilities.

Long-term patterns of hepatitis C virus RNA concentrations in a cohort of HIV seronegative men with bleeding disorders

Little is known about the natural history of hepatitis C virus (HCV) RNA concentrations over the course of infection. The aim of this study was to describe the natural history of HCV RNA concentrations in 85 HIV negative men with bleeding disorders infected with HCV for up to 30 years. HCV RNA concentrations were measured in yearly serum samples using a branched DNA assay. HCV RNA concentrations increased over time in this cohort. Two years after exposure to HCV, 53% of patients had undetectable concentrations and no patients had levels >7 log(10)(genome Eq/ml); by 20 years, these proportions had changed to 23% and 32% respectively. The RNA concentration correlated strongly with alanine aminotransferase (ALT; correlations of 0.41-0.71 depending on stage of infection) and aspartate aminotransferase (AST; 0.20-0.51) levels. Patients with haemophilia A had significantly higher HCV concentrations than those with other disorders. An effect of HCV genotype on HCV RNA concentrations became nonsignificant after excluding patients who were persistently HCV PCR negative and who could not be genotyped. The correlation of HCV RNA concentrations with other markers of liver function, such as ALT, means that studies with clinical outcomes are required to assess whether HCV RNA concentrations provide additional prognostic information to that provided by these other markers.

Stability of HCV-RNA level and its lack of correlation with disease severity in asymptomatic chronic hepatitis C virus carriers

This study examines the relationship between HCV-RNA levels and disease severity in 60 individuals with chronic hepatitis C virus infection. HCV-RNA levels were quantified by the branched DNA (bDNA) assay in 445 samples (median: eight samples per patient) obtained over a median of 40.4 months (95% confidence interval (CI): 37.0-42.5). The median log HCV-RNA level was 6.77 (95% CI: 6.62-6.92) molecular equivalents/mL (MEQ/mL). The median log range of HCV-RNA levels in individual patients over the course of the study was 0.89 (95% CI: 0.69-1.16). HCV-RNA level varied over time by less than one log in 62% of patients, by 1-1.5 logs in 22% and by greater than 1.5 logs in only 17%. Univariate analysis, revealed an inverse association between HCV-RNA levels and ALT levels (P=0.037). Univariate and logistic regression analysis showed no significant association between HCV-RNA levels and either the degree of inflammation or fibrosis. In contrast, there was a significant positive association between alanine aminotransferase (ALT) levels and histological activity especially in individuals with ALTs> 100 IU/L. Hence, HCV-RNA levels: (i) almost always fell within the dynamic range of the bDNA assay; (ii) were stable in asymptomatic chronically infected patients, with only a small proportion of patients exceeding a range of 1.5 logs; (iii) did not correlate with either the extent of inflammation or degree of fibrosis. In contrast, there was a strong association between ALT level and the histological severity of liver disease.

HCV genotype and "silent" HBV coinfection: two main risk factors for a more severe liver disease

To evaluate whether HCV genotype and a "silent" HBV infection may be related to a more severe clinical presentation of liver disease, 205 anti-HCV/HCV-RNA positive, HBsAg/anti-HBs negative patients with chronic hepatitis (113 males and 92 females; median age 55 years, range 18-77), were studied on presentation at the Liver Unit from January 1993 to December 1997. Presence of serum anti-HBc, in the absence of HBsAg and anti-HBs, was considered a marker of "silent" HBV infection. Of the 205 patients, 134 had undergone percutaneous liver biopsy. Two main diagnosis groups were established: the mild liver disease group (76 patients), and the severe liver disease group (109 patients); 20 patients who had refused to undergo liver biopsy were not included in the clinical and virological evaluation because the diagnosis was uncertain. The prevalence of severe liver disease was similar in the genotype 1 and non-1 groups (61.3% of 98 patients with genotype 1 and 52.9% of 70 patients with a non-1 genotype). Instead, the 88 patients with "silent" HBV infection showed a higher percentage of severe liver disease than the 97 anti-HBc negative patients (72.7% vs. 46.4%, respectively: P < 0.0005). Of the 88 anti-HBc positive patients, the prevalence of those with severe liver disease was similar in the 32 cases with serum HBV-DNA as detected by PCR and in the 56 HBV-DNA negative (81.2% vs. 67.8%, P = 0.4). The relation between "silent" HBV infection and severe liver disease was observed both in genotype 1 and non-1 infected patients. Nevertheless, the anti-HBc negative patients infected by genotype 1 showed a severe liver disease more frequently than those infected by a non-1 genotype, with a difference that is significant to the statistical analysis (P < 0.05). The findings suggest that "silent" HBV infection in anti-HCV positive chronic hepatitis enhances the severity of the liver disease. Evidence was also found that in patients without "silent" HBV infection there is a correlation between the presence of HCV genotype 1 and the severity of liver disease.

Oxidative stress in symptom-free HCV carriers: relation with ALT flare-up

BACKGROUND

The reason why some hepatitis C virus carriers with normal aminotransferase activity present, during time, an activation of the disease, is unknown. The aim of this study was to assess the oxidative balance in such patients and to evaluate its possible role on the severity of disease.

MATERIALS AND METHODS

Histology, glutathione and malondialdehyde were determined in the liver of 30 HCV-RNA positive patients with persistently normal aminotransferase. Patients were followed-up for 18 months with plasmatic determinations of aminotransferase, ferritin, glutathione, malondialdehyde, carbonyl and sulphydryl protein levels (every 2 months) and serum HCV-RNA (every 3 months).

RESULTS

Four subjects had normal histology, whereas the remaining 26 showed mild/moderate chronic hepatitis. Hepatic glutathione and malondialdehyde concentrations were normal in 16 patients and clearly altered in the other 14. The hepatic redox state did not correlate with histology whereas it correlated with plasmatic oxidative markers. During the study, aminotransferase flared up in 11 patients, 9 of these (82%) having at enrollment an altered hepatic oxidative balance. Patients with aminotransferase elevation showed increased blood indices of oxidative stress, which occurred earlier than aminotransferase flare-ups. No oxidative stress was observed in the remaining subjects.

DISCUSSION

This study suggests that symptom-free HCV carriers with impaired redox state have a higher risk of aminotransferase flare-up; therefore the impaired oxidative balance may have a prognostic significance on disease activity.

Nuclear localization and intramolecular cleavage of N-terminally deleted NS5A protein of hepatitis C virus

The full-size NS5A (NS5A-F) of hepatitis C virus is localized in the cytoplasm despite the presence of a functional nuclear localization signal (NLS) in its C-terminal region (amino acids (aa) 354-362). In the present study, we demonstrated that a short stretch of sequence near the N-terminus of NS5A (aa 27-38) masked the functional NLS, preventing NS5A from being transported to the nucleus. This sequence, referred to as an NLS-masking sequence, was distinct from a nuclear export signal, as it did not actively target a protein to the cytoplasm. We also found that other sequences located at either an N- (aa 1-21) or a C-terminal region (aa 353-447) were responsible for targeting NS5A to the cytoplasm. Western blot analysis of the transfected cells revealed that NS5A mutants that had been N-terminally deleted by 66 aa or more were cleaved at a certain cleavage site, generating a common fragment of ca. 40 kDa. This result implies the possible presence of a cleavage site in the NS5A sequence around aa 150, which is exposed through conformational alteration upon the N-terminal deletions.

Serotyping and genotyping of hepatitis C virus in Taiwanese patients with type C chronic liver disease and uraemic patients on maintenance haemodialysis

BACKGROUND

To evaluate a recombinant immunoblot hepatitis C virus (HCV) serotyping assay, which determines HCV serotypes 1, 2, and 3 by detecting type-specific antibodies to core-and NS-4-derived peptides.

METHODS

Immunoreactivity of type-specific antibodies among 173 chronic hepatitis C patients and 43 haemodialysis patients in Taiwan was examined and the serotyping results were compared with genotyping by Okamoto's method. Serial specimens from 29 patients undergoing interferon-alpha therapy were also evaluated.

RESULTS

Of the 205 specimens for which genotyping data were available, 51.2% were of serotype 1, 31.7% of serotype 2, 1.0% of serotype 3, 2.4% of either serotype 1 or 3, and the remaining 13.7% were untypable. The serotypable rate was significantly lower in haemodialysis patients than in chronic hepatitis C patients (70.0% vs 94.9%; P < 0.001). Serotyping of genotype 2b specimens was significantly more dependent on core peptide bands than other genotypes. Using genotyping as the reference, the overall sensitivity, specificity and concordance of the recombinant immunoblot HCV serotyping assay were 86.3%, 97.2% and 83.9%, respectively. However, the serotyping assay had significantly lower sensitivity (69.2%), specificity (77.8%) and concordance (53.8%) for genotype 2b specimens. Of nine HCV complete responders, one lost type-specific antibodies 6 months after the cessation of interferon-alpha treatment.

CONCLUSIONS

These results suggest that, except for less than optimal performance with immunocompromised or genotype 2b patients, the HCV serotyping assay is a practical and useful method for HCV typing in the clinical setting in Taiwan.

Combination therapy with interferon and ribavirin in the treatment of chronic hepatitis C infection

OBJECTIVE

To review and critique the medical literature regarding the combination of interferon and ribavirin in the initial treatment of chronic hepatitis C virus (HCV) infection.

DATA SOURCES

A MEDLINE search (January 1966-June 1999) was conducted to identify human clinical trials regarding the combination of interferon and ribavirin therapy for the initial treatment of chronic HCV. Bibliographies were reviewed for relevant literature.

STUDY SELECTION

Clinical trials of combination interferon and ribavirin for the treatment of chronic HCV in interferon-naïve adults were reviewed.

DATA SYNTHESIS

The combination of ribavirin and interferon in the treatment of chronic HCV has been beneficial in patients who are interferon-naïve. Patients with predictors of poor response, such as baseline cirrhosis, male gender, age >40 years, high baseline viral loads (>2 x 10(6) copies/mL), and genotype 1 respond better to combination treatment when compared with those who receive interferon monotherapy. Patients with genotype 1 and/or high viral loads may benefit most from 48 weeks of combination therapy; however, adverse effects are of greater concern in these patients. Monitoring can limit these complications.

CONCLUSIONS

Combination therapy is effective in the treatment of interferon-naive patients with chronic HCV infection. Patients should be evaluated for duration of treatment with combination therapy by determination of predictors of response. Further trials are needed to more closely evaluate the duration of treatment and to determine the best patient population to receive combination therapy.

Hepatitis C virus genotypes in a non-cirrhotic Italian population with chronic hepatitis C: correlation with clinical, virological and histological parameters. Results of a prospective multicentre study

To identify correlations between the distribution of hepatitis C virus (HCV) genotypes and demographic, pathological and virological parameters of HCV-infected patients, we prospectively recruited 650 patients with biopsy-proven chronic hepatitis C without histological aspects of cirrhosis; none had been treated with antiviral therapy. Data regarding gender, age, mode of HCV transmission, alanine aminotransferase (ALT) and HCV RNA levels, immunoglobulin M (IgM) anticore values, liver histology and histological activity were obtained from each patient and correlated on multivariate analysis with infecting HCV genotype. Fifty-five per cent of the patients were infected with HCV genotype 1, 20% with HCV genotype 2, 18% with HCV genotype 3 and 7% with HCV genotype 4. Non-transfusional HCV transmission, low ALT levels, IgM anticore reactivity and a low histological grading score were independent variables associated with HCV genotype 1. Older age, female gender, post-transfusional transmission and a high histological grading score were related to HCV genotype 2, whilst younger age, history of current/previous drug abuse, high ALT values, low IgM anticore reactivity and high viraemic levels were associated with HCV genotype 3. History of illicit use of intravenous drugs and low HCV RNA levels were the only independent variables correlated with HCV genotype 4. Genotype 1 remains predominant in Italy but the prevalence of HCV genotypes is changing in relation to age and mode of transmission: Italian patients with HCV genotype 3 are younger and exhibit higher levels of ALT and HCV RNA than patients with other genotypes.

Prevalence of mixed infection by different hepatitis C virus genotypes in patients with hepatitis C virus-related chronic liver disease

Multiple infection by different hepatitis C virus (HCV) genotypes may be of great clinico-pathologic interest. In this study we determined the effective prevalence of coinfections by two or more HCV genotypes in 213 subjects with HCV-positive chronic hepatitis by using genotype-specific polymerase chain reaction (PCR), genotype-specific probe hybridization, and direct sequencing. The most prevalent genotype was HCV-1b (54%). HCV-2 (a/c) was also prevalent (27%), and types 1a and 3a were found in 5% and 3% of patients, respectively. A mixed infection was detected in 23 patients (10.8%): 4 out of 23 were coinfected by types 1a + 1b, while the remaining 19 patients had a b + 2 (a/c) mixed infection. Further analysis based on restriction fragment length polymorphism (RFLP) on type-specific PCR products was used to verify genotyping results. Only four coinfections (1a + 1b in 2 patients and 1b + 2 (a/c) in the remaining 2 patients, respectively) were confirmed by enzyme cleavage. All patients with true coinfection had long-lasting infection and liver cirrhosis. Both true and false mixed infections resulting from RFLP analysis were confirmed by direct sequencing of type-specific amplification products. We also determined a recurrent C/T transversion at position 618 in all sequenced samples. In 4 cases another point mutation (G/A at position 626) was found, reducing the number of mismatches between HCV-2 and HCV-1b from 4 to 3 (or 2). Interestingly, all HCV-2 isolates sequenced showed the highest degree of nucleotide homology with HCV-2 subtype c, confirming the relatively high prevalence of this subtype in Italy. In conclusion, we showed the possibility of multiple infection by different HCV types in the general population of chronically infected patients without particular risk factors, even if in a low percentage of cases. Further studies are needed to assess the clinical relevance of chronic HCV infection with multiple genotypes.

Prognosis of chronic hepatitis C: results of a large, prospective cohort study

The prognosis of chronic hepatitis C virus (HCV) infection is still ill-defined. The present study prospectively evaluated mortality and complications in a large cohort of patients with chronic hepatitis C. The study included 838 anti-HCV and HCV-RNA-positive patients who were followed for 50.2 +/- 26.9 months (mean +/- SD; range, 6-122 months) in a prospective protocol. During follow-up, 62 patients died (31 from liver disease and 31 from other causes), and 12 patients needed liver transplantation. When compared with a matched general population, hepatitis C increased mortality mainly when cirrhosis was present and in patients who were less than 50 years old at study entry. During follow-up, a further 30 patients developed nonlethal complications of cirrhosis. By multivariate regression, survival was decreased by cirrhosis, long disease duration, history of intravenous drug abuse, and excessive alcohol consumption, whereas interferon therapy improved survival. Alanine transaminase (ALT), bilirubin, sex, and genotype had no effect on survival. The risk of hepatocellular carcinoma (HCC) (n = 17) was increased by cirrhosis and to a lesser degree by long disease duration and high bilirubin, whereas interferon therapy, genotype, and other factors had no effect. Chronic hepatitis C is a disease with considerable mortality and morbidity when cirrhosis is present at diagnosis. Patients who acquire the infection early in life have a markedly increased mortality even when cirrhosis is absent at diagnosis. The age at diagnosis therefore should play a major role in therapeutic considerations. The present data also suggest that interferon therapy has a long-term clinical benefit, although it did not reduce the risk of liver cancer.

HCV genotypes in Northern Italy: a survey of 1368 histologically proven chronic hepatitis C patients

BACKGROUND/AIMS

Hepatitis C virus (HCV) easily undergoes genomic changes, thus accounting for the presence of different genotypes, with different geographic distributions and different outcomes of chronic hepatitis. Type 1b is frequently found in advanced diseases; however, since this genotype is the most prevalent in older patients, the association with advanced age and severity of the disease is confounding. The aim of this study was to assess changes in the prevalence of HCV genotypes by surveying a large population of chronic hepatitis C patients in Northern Italy, and to assess if the high prevalence of genotype 1b in older patients with advanced diseases simply reflects the duration of HCV infection, rather than intrinsic biological properties of HCV.

METHODS

We studied 1368 HCV-RNA positive patients, with histologically proven chronic hepatitis. Drug addiction, blood transfusions and sporadically acquired infections represented the risk factors.

RESULTS

Genotype 1b, the most prevalent isolate, and genotype 2a were associated with older age, cirrhosis, sporadically-acquired infections and blood transfusion, while types 1a, 3a, and 4 were associated with younger age, chronic persistent hepatitis and drug addiction. Patients with a history of transfusions were divided into four groups depending on the period of transfusion. The prevalence of genotype 1b decreased with time. Type 3a appeared only after 1979.

CONCLUSION

The severity of chronic hepatitis C could be related more to the duration of the infection rather than to the intrinsic pathogenicity of HCV genotypes.

Prediction of cirrhosis in patients with chronic hepatitis C infection by artificial neural network analysis of virus and clinical factors

The diagnosis of cirrhosis in patients with hepatitis C virus (HCV) infection is currently made using a liver biopsy. In this study we have trained and validated artificial neural networks (ANN) with routine clinical host and viral parameters to predict the presence or absence of cirrhosis in patients with chronic HCV infection and assessed and interpreted the role of the different inputs on the ANN classification. Fifteen routine clinical and virological factors were collated from 112 patients who were HCV RNA positive by reverse transcriptase-polymerase chain reaction (RT-PCR). Standard and Ward-type feed-forward fully-connected ANN analyses were carried out both by training the networks with data from 82 patients and subsequently testing with data from 30 patients plus performing leave-one-out tests for the whole patient data set. The ANN results were also compared with those from multiple logistic regression. The performance of both ANN methods was superior compared with the logistic regression. The best performance was obtained with the Ward-type ANNs resulting in a sensitivity of 92% and a specificity of 98.9% together with a predictive value of a positive test of 95% and a predictive value of a negative test of 97% in the leave-one-out test. Hence, further validation of the ANN analysis is likely to provide a non-invasive test for diagnosing cirrhosis in HCV-infected patients.

Chronic hepatitis C: the virus, its discovery and the natural history of the disease

The identification of hepatitis A and hepatitis B led to the recognition that a third virus was capable of causing blood-borne hepatitis. The pathogen responsible for this nonA, nonB hepatitis was identified in the late 1980s and subsequently named hepatitis C. Since the discovery of hepatitis C there has been a pandemic of research publications describing the natural history of the infection and it is now known that this virus can cause serious liver damage in a proportion of infected patients. It is now clear that the effects of infection with hepatitis C and alcohol misuse are additive and that there is an increased risk of hepatic complications in infected patients who abuse alcohol.

Intravenous natural beta-interferon in white patients with chronic hepatitis C who are nonresponders to alpha-interferon

OBJECTIVES

alpha-Interferons (alpha-IFN) have been shown to be effective in the treatment of chronic viral C hepatitis, but their efficacy remains unsatisfactory. Recently natural beta-interferon (beta-IFN) administered by intravenous infusion has been used successfully.

METHODS

To evaluate the efficacy and safety of intravenous beta-IFN administration we treated 20 patients with histologically proven chronic hepatitis C who were nonresponders to at least two previous courses of alpha-IFN treatment. All patients received 6 million units (MU) of natural human fibroblast beta-IFN by drip infusion, 6 times per wk for 8 wk and were followed up for 6 months after suspension of treatment.

RESULTS

Five patients (25%) had response at the end of treatment; of these patients only one had sustained response. Patients who responded to therapy had lower, although not significantly, baseline levels of HCV RNA, compared with nonresponders. Whereas mean viral load decreased during therapy, only two patients were HCV RNA negative at the end of treatment, but none were at the end of the follow-up period. Genotype 1 was found in 17 cases, genotype 2 was found in one case, and a combination of genotypes 1b and 2a was found in the remaining two cases. Therapy was well tolerated and beta-IFN administration was neither interrupted nor its dosage reduced due to side effects in any of the patients.

CONCLUSIONS

Our study shows that intravenous beta-IFN is well tolerated and that the modest results obtained may depend on the brevity of treatment. Consequently, further studies are needed to define the optimum dose, schedule, and duration of treatment to eradicate HCV infection.

Hepatitis viruses: genetic variants and clinical significance

Variants of hepatitis B, C, and delta virus have been identified in patients both with acute and chronic infections. In the hepatitis B virus genome, naturally occurring mutations have been found in all viral genes, most notably in the genes coding for the structural envelope and nucleocapsid proteins. In the hepatitis C virus genome, the regions coding for the structural envelope proteins E1 and E2, as well as the 3'-contiguous non-structural region NS1, were found to be hypervariable. Viral variants may be associated with a specific clinical course of the infection, e.g., acute, fulminant or chronic hepatitis. Specific mutations may reduce viral clearance by immune mechanisms ('vaccine escape' and 'immune escape'), response to antiviral therapy ('therapy escape'), as well as detection ('diagnosis escape'). The exact contribution, however, of specific mutations to the pathogenesis and natural course of hepatitis B, C, or delta virus infection, including hepatocellular carcinoma development, and the response to antiviral treatment remains to be established.

The natural history of chronic hepatitis C virus infection

In conclusion, the natural history of chronic HCV infection has not yet been fully defined. Current data suggest that the process runs an indolent course during the first two decades after initial infection, accounting for modest morbidity and mortality. Serious sequelae are more likely to emerge as the disease process enters the third and fourth decades after infection. These sequelae will presumably be concentrated among those whose liver biopsies display features of cirrhosis, but seem less likely to effect those with liver biopsy evidence of chronic hepatitis alone unless their disease advances to cirrhosis. The frequency of progression from chronic hepatitis to cirrhosis as the disease process enters the third decade remains to be determined. Associated chronic alcoholism appears to be an important additive factor, but other factors that might promote disease progression need to be defined. It seems probable that end-stage liver disease will result in only a proportion of infected individuals. If so, the challenge is to learn how to determine for each individual during the course of their chronic illness what outcome can be expected.

HCV genotypes in Morocco

To determine the hepatitis C virus (HCV) genotypes circulating in Morocco, virus isolates from 105 chronically infected and 19 hemodialysis patients were examined using the line probe assay. Genotypes 1 and 2 only were found among Moroccan patients. Subtypes 1b (47.6%) and 2a/2c (37.1%) were the most common, whereas subtype 1a (2.8%) was less common. Among the hemodialysis patients, only genotype 1 was found with a prevalence of 68.4% for subtype 1b and 15.8% for the subtype 1a. It was also shown that the HCV genotypes distribution varies with age in both studied populations. Subtype 1b was most prevalent among older patients, whereas subtype 2a/2c was mainly found among younger ones. Although Morocco belongs to the African continent, the circulating HCV strains are similar to those observed in some American and European countries.

Evidence for a deficiency of interferon response in mononuclear cells from hepatitis C viremic patients

BACKGROUND/AIMS

The pathophysiology of chronic hepatitis C and the mechanisms of resistance to interferon alpha are poorly understood. The aim of this work was to assess the influence of HCV infection and the viral genotype on lymphocyte production of 2',5' oligo-adenylate synthetase activity and monocyte production of TNF alpha and IL1 beta.

METHODS

Mononuclear cells from 50 consecutive patients were studied after 6 months of interferon treatment. Patients with persistent viremia (PCR-positive, elevated ALT, n = 39) were compared with the PCR-negative patients with normal ALT activity (n = 11) of similar age and sex ratio.

RESULTS

Cells from the viremic patients showed lower basal and stimulated 2',5' oligo-adenylate synthetase activity, and a lower in vitro response capacity to human recombinant interferon. In contrast, no difference was observed in basal and stimulated TNF alpha or IL1 beta production between the two groups. In the PCR-positive patients the viral genotype had no significant influence on the response of mononuclear cells to interferon or endotoxin.

CONCLUSIONS

These results show that the presence of HCV in blood is associated with an elective defect in interferon system activation, independently of the viral genotype.

The prevalence of HCV infection in a cohort of pregnant women, the related risk factors and the possibility of vertical transmission

The prevalence of antibodies for one or more HCV antigens was 2.3% of 1,347 mothers at childbirth. Compared with the principal factors studied, the presence of antibodies was more frequent in women who were carriers of HIV infection (3/3), in those who had suffered liver diseases (5/37) or who had had transfusion (3/25). This was as opposed to women who did not have any risk factor (p < 0.001). The prevalence of HCV-RNA was 1.3%; in relation to the antibody state, such a condition was more frequent in subjects with antibodies for 3 or 4 antigens (about 80%) compared with those who were positive for 1 or 2 antigens. HCV-RNA of the same genotype as the mother (type 1; 1a) was also found in the funicular blood of 2 of the 18 babies born to mothers who were positive for HCV-RNA. In the course of the follow-up (from the 3rd to the 18th month) the viral RNA was not found in any of the babies, nor was it found in the 2 who were positive at birth. Even the antibodies gradually disappeared, although slowly. At the 10th month, 91% of the babies resulted as having no antibodies and at the 18th month none of the babies resulted as having antibodies. Breast-feeding also appeared to have no influence on the transmission of the infection; out of 18 viremic mothers indeed 12 (67%) breast-fed their babies.

Nuclear localization of the NS3 protein of hepatitis C virus and factors affecting the localization

Subcellular localization of the NS2 and NS3 proteins of hepatitis C virus was analyzed. In stable Ltk transfectants inducibly expressing an NS2-NS3 polyprotein (amino acids [aa] 810 to 1463), processed full-size NS2 (aa 810 to 1026) was detected exclusively in a cytoplasmic membrane fraction. On the other hand, the other processed product, carboxy-truncated NS3 (NS3 deltaC1463; aa 1027 to 1463), was present in both cytoplasmic and nuclear fractions. To further analyze subcellular localization of NS3, NS3 deltaC1459 (aa 1027 to 1459), full-size NS3 (NS3F; aa 1027 to 1657), and both amino- and carboxy-truncated NS3 (NS3 deltaNdeltaC; aa 1201 to 1459) were expressed in HeLa cells by using a vaccinia virus-T7 hybrid expression system. NS3 deltaC1459 and NS3F accumulated in the nucleus as well as in the cytoplasm, exhibiting a dot-like staining pattern. On the other hand, NS3 deltaNdeltaC was localized predominantly in the cytoplasm, suggesting the presence of a nuclear localization signal(s) in the amino-terminal sequence of NS3. NS4A, a viral cofactor for the NS3 protease, inhibited nuclear transport of NS3 deltaC1459 and NS3F, with the latter inhibited to a lesser extent than was the former. Interestingly, wild-type p53 tumor suppressor augmented nuclear localization of NS3 deltaC1459 and NS3F, whereas mutant-type p53 inhibited nuclear localization and augmented cytoplasmic localization of NS3 deltaC1459. However, subcellular localization of NS3 deltaNdeltaC was not affected by either type of p53. Wild-type p53-mediated nuclear accumulation of NS3 deltaC1459 and NS3F was inhibited partially, but not completely, by coexpressed NS4A, with NS3F again affected less prominently than was NS3 deltaC1459.

HCV genotypes in patients with liver disease of different stages and severity

AIMS/MATERIAL: Hepatitis C virus (HCV) genotyping was performed in 213 anti-HCV-positive patients with chronic liver disease ranging from minimal histological changes to hepatocellular carcinoma. One hundred and twenty-two patients had non-cirrhotic chronic active or persistent hepatitis (including 29 who were asymptomatic with persistently normal ALT levels) (chronic liver disease group). The other 91 had hepatocellular carcinoma and, in all but three cases, cirrhosis (hepatocellular carcinoma group).

RESULTS

The overall prevalence of HCV variants was: 54.9% type 1b, 37.8% type 2, 2.5% type 1a, 2.0% type 3a, 2.0% type 4a. The genotype distribution showed no relation to the stage (chronic liver disease vs. hepatocellular carcinoma) or severity (chronic active vs. chronic persistent hepatitis) of the liver disease, or to the duration of the disease (<10 years vs. >10 years). Within the hepatocellular carcinoma group, the duration of type-1b disease was similar to that of type-2 infections. Ages at the time of infection and genotype were both independently associated with progression to cirrhosis and hepatocellular carcinoma, but multivariate analysis revealed that the effect of age was much stronger than that of genotype 1b.

CONCLUSIONS

The predominance of HCV type 1b in this study reflects the higher frequency of this variant in our area. Our findings indicate that infections caused by each HCV genotype are capable of progressing to hepatocellular carcinoma.

The relationship of histology to genotype in chronic HCV infection

The histological description of chronic hepatitis is undergoing considerable change at present. It has become important to define chronic hepatitis aetiologically and then define levels of necro-inflammatory change (grade) and fibrosis (stage). The aim of this study was to compare the ability of different histological scoring systems to detect differences in the pathological changes associated with infection with the different HCV genotypes that are known to have different natural histories. The histological appearances of liver biopsies from 29 HCV infected patients were compared by the Knodell histological activity index (HAI), modified histological activity index and the Scheuer histological scoring system. HCV genotyping was performed for each patient by sequence analysis of the 5' non-coding region. The histological appearances from HCV 1 infected patients showed a tendency towards more active necro-inflammatory changes when compared with those from HCV 2 or 3 infected patients. The levels of fibrosis were similar for all genotypes. The modified HAI and Scheuer scoring systems detected differences, not revealed by the Knodell system, in the types of inflammatory pathology produced by the different genotypes of HCV. In particular these scoring systems noted significant differences in the component scores of inflammation, in addition to the total inflammatory scores. In conclusion, the recently introduced scoring systems were able to detect differences in liver pathology produced by infection of similar duration with different viral genotypes. As genotype is considered an important determinant of disease progression and response to anti-viral therapy, it is likely that those scoring systems correlating with genotype will yield more useful histological information than those that do not.

Evaluation of two simplified methods for genotyping hepatitis C virus

A number of different approaches have been used for genotyping hepatitis C virus (HCV). Two simplified methods were evaluated, both of which used polymerase chain reaction (PCR) to amplify products from the 5' non-coding region of HCV: non-isotopic restriction fragment length polymorphism (RFLP) analysis and type-specific PCR. Sixty-four viraemic patients suffering from chronic HCV infection were studied using these two techniques; 25/64 samples were further tested with a commercial serotyping ELISA based on synthetic NS4 antigen (Murex, U.K.). The results of the three typing methods were generally in agreement with each other. When only the predominant genotype identified by each method was analysed, the 3 methods had 100% agreement. RFLP did not detect any mixed infections and it was unsuccessful in 16/64 (25%) samples. Both type-specific PCR and serotyping ELISA detected mixed infections. However, serotyping ELISA did not give typeable results in 7/25 (28%) samples, whereas type-specific PCR gave typeable results in all 64 samples. Type-specific PCR detected more mixed infections than serotyping ELISA. Direct sequencing of four PCR products with indeterminate RFLP confirmed changes in restriction enzyme recognition sites. The sequences also confirmed the validity of the predominant genotype in cases of apparent mixed infections. It is possible that some of these cases were artefacts as a result of quasispecies.

Distribution of hepatitis C virus genotypes in German patients with chronic hepatitis C: correlation with clinical and virological parameters

BACKGROUND/AIMS

The hepatitis C virus genotypes have been shown to be differently distributed between distinct geographical areas and to be associated with different clinical presentations. In the present study we investigated the distribution of HCV genotypes in 379 German patients with chronic hepatitis C in relation to age, sex, route of infection, liver histology and viremia.

METHODS

Typing of HCV was done using restriction fragment length polymorphism analysis as well as a DNA enzyme immunoassay. HCV RNA concentrations were determined by quantitative polymerase chain reaction. Liver biopsies were performed in 187 patients and the histological activity was graded by the Knodell score.

RESULTS

Seventy percent were infected with genotype 1 (20% subtype 1a, 80% subtype 1b), 4% with genotype 2 and 26% with genotype 3 (all subtype 3a). Genotype 3a and 1a infection was significantly associated with intravenous drug abuse. In contrast, genotype 1 predominated in patients with post-transfusion hepatitis and infection of unknown origin. A changing relative prevalence of HCV genotypes in relation to age was also observed. Patients with genotype 3 infection showed significantly lower HCV RNA levels and a lower mean histological activity score as compared to patients with genotype 1 and genotype 2. However, using multivariate analysis, only age and mode of transmission but not histological activitiy score were shown to be independent variables.

CONCLUSIONS

Our study confirms previous reports from other countries that HCV variants can be classified into a relatively small number of discrete genotypes, and that the subtype 1b clearly predominates. However, we found evidence that there is a changing relative prevalence of HCV genotypes in relation to age, and that the mode of transmission is reflected in the predominance of certain genotypes.

Hepatitis C virus genotypes in a cohort of Australian blood donors and haemophiliac and liver transplant patients

The aim of the present study was to characterize hepatitis C virus (HCV) genotypes using the INNO-LiPA HCV line probe assay and direct sequencing from three different HCV-RNA-positive (serum) groups: (i) blood donors (n = 59); (ii) haemophiliacs (n = 43); and (iii) patients undergoing liver transplantation (n = 26). Of 128 HCV-RNA-positive samples, 74 (58%) were genotype 1. Of these, 41 were genotype 1a, 32 were genotype 1b and one was genotype 1 indeterminate. Of the remaining 54 samples, seven (5%) were genotype 2a, two (2%) were genotype 2b, 26 (20%) were genotype 3a, three (2%) were genotype 4a, while 16 (12.5%) were of a mixed genotype. There was no significant difference between the three groups with regard to the prevalence of any specific genotype. However, in blood donors and haemophiliac patients there was a statistically significant difference in the occurrence of genotype 3a in patients with elevated alanine aminotransferase (ALT) levels (30.3%) compared with those patients with persistently normal ALT levels (5.6%; P = 0.004; chi 2). Genotype 3a was also uncommon in liver transplant patients (one of 14) with "sporadic' HCV infection. Genotype 4a was detected only in liver transplant patients. These patients had originated from Egypt (n = 1), Italy (n = 1) and Romania (n = 1).