Hepatitis C virus genotypes, reactivity to recombinant immunoblot assay 2 antigens and liver disease

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.

Hepatitis C virus genotype 1b as a risk factor for hepatocellular carcinoma development: a meta-analysis

BACKGROUND/AIMS

Hepatitis C virus (HCV) is a known risk factor for hepatocellular carcinoma (HCC), but whether the risk varies among patients infected with different HCV genotypes is still controversial. We performed a meta-analysis to clarify whether the genotype 1b is associated with a higher risk of HCC than other genotypes.

METHODS

We identified 57 relevant papers through a literature search to December 2007 but, since age could represent a major confounder, we focused the meta-analysis on the 21 studies presenting age-adjusted risk estimates for HCV genotype 1b vs. other genotypes. We used random-effects models with the DerSimonian-Laird method and assessed heterogeneity between studies and publication bias.

RESULTS

Patients infected with HCV genotype 1b have almost double the risk to develop HCC than those infected with other genotypes (Relative Risk (95% Confidence Intervals) = 1.78(1.36-2.32)). The pooled risk estimate was somewhat lower when we restricted the analysis to the eight studies conducted in patients with liver cirrhosis (1.60;1.07-2.39) or considering the 36 studies presenting only crude data (1.63;1.30-2.06). In seven studies excluding patients with liver cirrhosis, the RR (95% CI) increased to 2.46(1.69-3.59).

CONCLUSIONS

This meta-analysis suggests that HCV genotype 1b plays an important role in HCC development, especially in patients with early stage liver disease.

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.

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.

Low-level hepatitis C viremia and humoral immune response to NS4 in chronic hepatitis B virus-hepatitis C virus coinfection

BACKGROUND

There is a limited amount of published data on the interference of hepatitis B virus (HBV) on hepatitis C virus (HCV). The aim of this study was to investigate the effect of concurrent HBV infection on serum titers of HCV RNA and HCV antibody profiles in chronic HCV infection.

METHODS

The clinical and virological profiles (serum titers of HCV RNA, HCV genotypes and antibody profiles) of 25 patients with chronic HBV-HCV coinfection were compared with those of 25 age- and sex-matched patients with HCV infection alone.

RESULTS

Among the 25 patients with HBV-HCV coinfection, only 3 were found hepatitis Be antigen (HBeAg) and HBV DNA positive by hybridization assays, and the other 11 were found HBV DNA positive by polymerase chain reaction. Genotype 1b was dominant in both HBV-HCV coinfection and HCV infection alone (64% versus 84%, P > 0.1). Patients with HBV-HCV coinfection had significantly lower alanine aminotransferase (ALAT) levels and inflammatory scores but higher fibrosis scores than those with HCV infection alone. Serum titers of HCV RNA were significantly lower in HBV-HCV coinfection than in HCV infection alone. The frequency and relative intensity of antibody response to core, E2/NS1, NS3, and NS5 showed no significant difference between the two groups, but antibody response to NS4 was diminished significantly in HBV-HCV coinfection.

CONCLUSIONS

In HBV-HCV coinfection, serum levels of HBV DNA are usually low or undetectable. Concurrent HBV infection, however, could interfere with HCV replication and suppress antibody response to NS4. The biological significance of selective inhibition of humoral immune response to NS4 in HBV-HCV coinfection should be further studied.

Cross-reactivity and clinical impact of the antibody response to hepatitis C virus second envelope glycoprotein (E2)

The genotype of hepatitis C virus (HCV) can profoundly affect the success of antiviral therapy for HCV infection. A possible contributing factor is a varied immune response elicited by infection with different HCV genotypes. In this study, full-length E2 proteins of HCV genotypes 1a, 1b, 2a, and 2b were used to determine the fraction of the humoral immune response to HCV E2 that is genotype specific. Greater than 90% of all infected individuals had serum antibodies to the four E2 proteins. Overall, individuals infected with genotype 1a or 1b were characterized by variable immune responses to HCV E2 with relatively high amounts of cross-reactivity with other E2 proteins. Individuals infected with genotype 2a or 2b exhibited a strong preferential reactivity to genotype 2a and 2b E2 proteins. Individuals with elevated titers to HCV E2 were more likely to be infected with genotype 2a and had a significantly lower median viral load. These findings indicate that the antibody response to HCV E2 is affected by the genotype of the virus and that induction of a strong humoral immune response to HCV E2 may contribute to a decreased viral load.

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.

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.

Hepatitis C virus genotypes in Korea and their relationship to clinical outcome in type C chronic liver diseases

OBJECTIVES

The relationship between HCV genotype and the development of more serious liver disease has not been clearly established. This study was to investigate the distribution pattern of HCV genotypes in Korea and their relationship to the viremic level and to progression of chronic liver disease.

METHODS

Study population was 217 patients with type C chronic liver disease. They were divided into 4 groups; 83 patients with near-normal ALT (group 1), 64 patients with elevated ALT (group 2), 20 patients with decompensated liver cirrhosis (group 3) and 50 patients with hepatocellular carcinoma (group 4). HCV genotypes were determined by reverse transcription polymerase chain reaction (RT-PCR) using mixed primer sets, and then the fidelity of genotyping was confirmed by cloning and sequencing. HCV RNA concentration was measured by quantitative competitive RT-PCR for 23 patients in group 2.

RESULTS

The genotypes could be determined in 166 (76%) out of 217 patients. Type 1b and type 2a were predominantly occurring over the other types in somewhat similar frequency (45% and 51%, respectively). The genotype distribution of type 1b and 2a among four different groups showed 42% and 54% in group 1, 49% and 45% in group 2, 53% and 47% in group 3 and 41% and 57% in group 4; thus there was no significant difference in genotype distribution among 4 different disease groups. However, the viremia levels in patients with genotype 1b infection were significantly higher than those with genotype 2a.

CONCLUSION

Genotype 2a infection is as prevalent as genotype 1b in Korea, and genotype 2a infection may pose no less risk for progression of disease despite lower replication level than genotype lb infection.

Typing of hepatitis C virus antibody with specific peptides in seropositive blood donors and comparison with genotyping of viral RNA

BACKGROUND AND OBJECTIVES

Serotyping of antibody to hepatitis C virus (anti-HCV) with specific peptides has been developed as an alternate method for typing HCV infections. The method does not require a prior amplification of viral RNA sequences from the sample. Identification of the viral genotype may be relevant for prognosis and clinical management.

MATERIALS AND METHODS

We used a previously described HCV serotyping assay (RIBA HCV Serotype SIA kit, Chiron Corp.) to investigate the serotype in 191 samples from blood donors selected for anti-HCV patterns (positive and indeterminate), ALT levels, and the presence or absence of viral RNA. The serotypes were compared with the genotypes obtained from typing the 5'-noncoding region of the viral RNA in 82 viremic samples.

RESULTS

We were able to obtain the viral serotype in 85% (114/134) of samples positive for anti-HCV but in only 3.5% (2/57) of the indeterminates. Lack of anti-NS4 in the sample was significantly associated with both untypable results and the presence of HCV serotypes other than serotype 1. The overall correlation with genotyping was 78% (64/82), rising to 95.5% (64/67) if only samples that could be both genotyped and serotyped were considered. The assay was easy to perform, gave reactivity patterns easy to interpret, and performed with high proficiency on anti-HCV-positive samples lacking detectable levels of viral RNA.

CONCLUSIONS

This is a practical and useful method for typing HCV infections in the clinical setting. The poor ability of the Core peptides to give the serotype in samples lacking anti-NS4 and the lack of specific peptides to recognize HCV types other than 1, 2, and 3 are, however, some aspects of the method that need improvement in the future.

Hepatitis C virus genotypes in northern Italy: clinical and virological features

We analyzed the characteristics of subjects from the same area who were infected with hepatitis C virus genotypes 1 through 4 and subtypes 1a and 1b. Our data are consistent with a rapid evolution in the epidemiology of HCV genotypes and argue against different pathogenic potentials for genotypes 1b and 2.

Incidence of hepatitis C virus infection in Italian patients with idiopathic pulmonary fibrosis

BACKGROUND

A viral cause of idiopathic pulmonary fibrosis (IPF) was recently suggested by a Japanese study in which a high prevalence of anti-hepatitis C virus (HCV) antibodies was detected. A subsequent British study failed to confirm these results.

METHODS

Antibodies to HCV were evaluated in 60 patients with IPF, 130 patients with non-interstitial lung disease, and in 4614 blood donors. HCV-RNA and HCV genotypes were evaluated in the anti-HCV positive patients with IPF. Anti-HCV antibodies were evaluated by ELISA and confirmed by recombinant immunoblotting assay (RIBA). HCV-RNA and genotypes were detected by reverse transcriptase polymerase chain reaction (PCR).

RESULTS

Eight patients with IPF had anti-HCV antibodies detected by ELISA (13.3%). In the blood donor control group the prevalence of HCV antibodies was lower (0.3%). In patients with non-interstitial lung disease HCV antibody prevalence was 6.1%. In all eight patients with IPF found to be anti-HCV positive by ELISA, HCV antibodies were also detected by RIBA. Furthermore, all were HCV-RNA positive by PCR assay. HCV genotypes were identified in four of these eight patients. In all four genotype II was present and in two it was associated with genotype III and/or genotype IV. In the remaining four cases the genotype was not identified.

CONCLUSION

Italian patients with IPF show an increased prevalence (approximately 13%) of HCV infection and viral replication, but the prevalence of anti-HCV antibodies does not differ from other lung diseases.

Prevalence of blood-borne viruses among intravenous drug users and alcoholics in Hiroshima, Japan

We investigated the prevalence of human immunodeficiency viruses-1 and 2 (HIV-1 and HIV-2), human T-lymphotropic virus type I and II, hepatitis B virus (HBV), hepatitis C virus (HCV) and hepatitis D virus among intravenous drug users (IVDU) in Hiroshima, Japan, where little is known about their present levels. From June to December 1993, serum samples were collected from 47 IVDU and 98 alcoholics in Hiroshima, Japan, and examined for markers of virus infection. The prevalence of antibody to HCV (anti-HCV) and/or HCV-RNA was significantly higher in IVDU than alcoholics (74.5% vs 20.4%, 44.7% vs 10.2% respectively, P < 0.001). In contrast, the prevalence of antibody to hepatitis B surface antigen and/or core antigen (anti-HBs and/or anti-HBc) showed no significant difference between the 2 groups (57.4% vs 66.3%). HIV-1 infection was found in one (2.1%) IVDU and genome analysis indicated that it was subtype B according to Myers' classification. Thus, an extremely low level of HIV infection and a high level of HCV infection was found in IVDU. Careful follow-up of this group is thought to be needed to minimize an outbreak of HIV-1 infection in Japan.

Epitope mapping of the NS4 and NS5 gene products of hepatitis C virus and the use of a chimeric NS4-NS5 synthetic peptide for serodiagnosis

Specific domains of the NS4 and NS5 gene products of hepatitis C virus have been identified using hydrophilicity profiles for the prediction of potential immunogenic regions, and epitope scanning techniques. Peptides synthesised on the basis of such data show excellent reactivity in the ELISA format. Introduction of a glycine-glycine spacer between two peptides (NS4-12 and NS5-44) to give a single chimeric peptides does not appear to impair immunoreactivity. An ELISA based on the chimeric peptide and a Core-NS3 recombinant protein correctly diagnoses a cohort of haemodialysed patients, three commercial HCV panels and the sera of a negative control population.

HCV genotypes in Swedish blood donors as correlated to epidemiology, liver disease and hepatitis C virus antibody profile

Sixty-two anti-HCV and HCV-RNA positive Swedish blood donors (44 men, 18 women; median age 34 years) were studied. HCV genotypes were correlated to parenteral risk factors, liver morphology, serum alanine aminotransferase (ALAT) levels and HCV antibody profile. Forty percent of the donors were infected with HCV genotype 1a, 10% with 1b, 21% with 2b, and 29% with 3a. Intravenous drug use (IVDU) was more common in donors with genotype 3a than in those with genotype 1a (p = 0.024), and prior blood transfusion more common in genotype 2b than in 3a (p = 0.012). Chronic active hepatitis with and without cirrhosis was found in 38% of donors infected with genotype 2b as compared to 8% of donors infected with 1a (p = 0.034). Forty percent of donors with genotype 1a had normal ALAT at the time of liver biopsy versus 11% with genotype 3a (p = 0.046). Antibodies to C33c and C22-3 were present in nearly all donors whereas reactivity to C100-3 and 5-1-1 was detected more often in donors with genotypes 1a and 1b as compared to donors with genotypes 2b and 3a. In conclusion, genotype 3a was correlated to IVDU or tattooing as parenteral risk factors for the acquisition of HCV infection, and genotype 2b to prior blood transfusion. Donors with genotypes 1a seemed to have less severe liver disease than those infected with genotypes 2b and 3a.

Rapid HCV RNA detection by PCR followed by a new non-radioactive liquid hybridisation assay and comparison with RIBA

A one-stage polymerase chain reaction (PCR) followed by an automated liquid hybridisation assay was used to examine anti-HCV-positive patients. The presence of HCV-RNA in 251 randomly selected enzyme immunoassay (EIA) positive clinical specimens was compared to their RIBA pattern. An association of a RIBA pattern with presence or absence of HCV-RNA was not detected. One hundred of these samples were also evaluated after dividing them into normal and elevated serum alanin aminotransferase (ALT) levels. PCR results were obtained on the basis of amplification products from two different gene regions (5'-NC region and NS 3). To prove the specificity of the PCR products, a commercially available digoxigenin-based liquid hybridisation assay was evaluated. The sensitivity was comparable to the results obtained after nested PCR. Based on the results of the study, the two-stage PCR can be changed in favour of the easier one-step PCR which offers the advantage of fewer contamination problems.

Host and viral features in chronic HCV infection: relevance to interferon responsiveness

Host and viral variables interact in determining the course and responsiveness to therapy of any viral infection. Presence of cirrhosis, serum levels of hepatitis C virus (HCV) RNA and the genotype of infecting virus are considered predictive of response to interferon (IFN) in chronic HCV infection. We evaluated these parameters in relation to IFN therapy in a cohort of anti-HCV-positive subjects with chronic hepatitis or cirrhosis. HCV RNA was detected by polymerase chain reaction (PCR) and by the branched DNA assay (bDNA), to quantify viraemia. HCV typing was performed by reverse-hybridization line probe assay. HCV RNA was detected in almost all anti-HCV-positive subjects with liver disease, PCR being more sensitive than bDNA. Hepatitis C viraemia was lowest in cirrhosis. Low pretreatment viraemia selected for those patients with chronic hepatitis obtaining a high rate of sustained response to IFN. The role of HCV type was less clearcut, due to the high prevalence in our population of type 1 (especially subtype 1b, accounting for 80% of cases). A trend towards a better response of non-1b genotypes was confirmed. This may be related to higher HCV RNA levels in type 1b-infected subjects. Cirrhosis remains however, independently from virological features, the strongest predictor of non-response to IFN.