Comparison of serum hepatitis C virus RNA and core antigen concentrations and determination of whether levels are associated with liver histology or affected by specimen storage time

Genetic variants of Nuclear Factor-Kappa B were associated with different outcomes of Hepatitis C virus infection among Egyptian patients

Background

Hepatitis C virus (HCV) is a major risk factor for chronic hepatitis and hepatocellular carcinoma (HCC). Nuclear factor kappa B (NF-κB) is a transcription factor that functions in health and disease. Genetic variants of the NF-κB gene can affect its function and are associated with chronic inflammatory changes and malignant transformation. This case-control study is aimed to determine the possible association between NF-κB genetic variants and different outcomes of HCV infection among Egyptian patients.

Subjects and Methods

295 subjects were recruited with allocation of participants in the representative group according to results of serological and molecular tests. Patients in the case group (group A) were further divided into three subgroups; subgroup I, mild chronic HCV, subgroup II, cirrhosis, and subgroup III, HCC subgroups (59 for each subgroup), group B included participants who experienced spontaneous viral clearance (n=59). All were compared to matched healthy control subjects, Group C (n=59). All participants were genotyped for NF-κB polymorphisms, rs11820062 by TaqMan assay and rs28362491 by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

Results

Risk analysis indicated that subjects carrying the rs11820062 A genotype are more susceptible to HCV infection (OR: 3.1; 95%, CI= 1.4-6.9). Subjects carrying the rs28362491 insertion genotype are at more risk of progression to cirrhosis when compared to healthy-controls and patients with mild chronic HCV (OR:7.7; 95% CI=2.4-24.3 and OR:5.1, 95% CI= 1.7-15.7, respectively) and also are at more risk of developing HCC when compared to healthy controls (OR:2.6; 95% CI= 0.94-7.3).

Conclusion

Polymorphisms affecting NF-κB different genes would modulate HCV infection susceptibility and clinical disease progression among Egyptian patients.

Modeling hepatitis C virus protein and p53 interactions in hepatocytes: Implications for carcinogenesis

Hepatitis C virus (HCV) infection has reached epidemic proportions worldwide. Individuals with chronic HCV infection and without access to treatment are at high risk for developing hepatocellular carcinoma (HCC), a liver cancer that is rapidly fatal after diagnosis. A number of factors have been identified that contribute to HCV-driven carcinogenesis such as scarring of the liver, and chronic inflammation. Recent evidence indicates a direct role for HCV-encoded proteins themselves in oncogenesis of infected hepatocytes. The viral protein HCV core has been shown to interact directly with the host tumor suppressor protein p53, and to modulate p53-activity in a biphasic manner. Here, biochemically-motivated mathematical models of HCV-p53 interactions are developed to elucidate the mechanisms underlying this phenomenon. We show that by itself, direct interaction between HCV core and p53 is insufficient to recapitulate the experimental data. We postulate the existence of an additional factor, activated by HCV core that inhibits p53 function. We present experimental evidence in support of this hypothesis. The model including this additional factor reproduces the experimental results, validating our assumptions. Finally, we investigate what effect HCV core-p53 interactions could have on the capacity of an infected hepatocyte to repair damage to its DNA. Integrating our model with an existing model of the oscillatory response of p53 to DNA damage predicts a biphasic relationship between HCV core and the transformative potential of infected hepatocytes. In addition to providing mechanistic insights, these results suggest a potential biomarker that could help in identifying those HCV patients most at risk of progression to HCC.

Epidemiology and natural history of hepatitis C virus infection

Hepatitis C virus (HCV) affects 130-210 million people worldwide and is one of the major risk factors for hepatocellular carcinoma. Globally, at least one third of hepatocellular carcinoma cases are attributed to HCV infection, and 350000 people died from HCV related diseases per year. There is a great geographical variation of HCV infection globally, with risk factors for the HCV infection differing in various countries. The progression of chronic hepatitis C to end-stage liver disease also varies in different study populations. A long-term follow-up cohort enrolling participants with asymptomatic HCV infection is essential for elucidating the natural history of HCV-caused hepatocellular carcinoma, and for exploring potential seromarkers that have high predictability for risk of hepatocellular carcinoma. However, prospective cohorts comprising individuals with HCV infection are still uncommon. The risk evaluation of viral load elevation and associated liver disease/cancer in HCV (REVEAL-HCV) study has followed a cohort of 1095 residents seropositive for antibodies against hepatitis C virus living in seven townships in Taiwan for more than fifteen years. Most of them have acquired HCV infection through iatrogenic transmission routes. As the participants in the REVEAL-HCV study rarely receive antiviral therapies, it provides a unique opportunity to study the natural history of chronic HCV infection. In this review, the prevalence, risk factors and natural history of HCV infection are comprehensively reviewed. The study cohort, data collection, and findings on liver disease progression of the REVEAL-HCV study are described.

Indeterminate third-generation hepatitis C recombinant immunoblot assay and HCV RNA analysis: Isolated reactivity against NS5 associated with HCV viraemia in clinical patients but not blood donors

It has previously been reported that singular reactivity against NS5 in the third generation hepatitis C virus (HCV) confirmatory recombinant immunoblot assay (RIBA-3) is not associated with detectable HCV RNA in sera. In order to investigate the significance of indeterminate HCV RIBA-3 results with particular regard to NS5, 165 sera with indeterminate RIBA-3 results were analysed for the presence of HCV RNA. Sera from blood donors constituted 58 of the 165 samples, whereas 11 were from immunocompromized patients. The remaining 96 sera were from non-immunosuppressed clinical patients. Of the 107 RIBA-3 indeterminate samples from clinical patients, 19 were HCV RNA positive (18%), with 3 of the 57 (5%) NS5 reactive samples having detectable HCV RNA. None of the 58 indeterminate samples obtained from blood donors had detectable HCV RNA. Thus, having an indeterminate RIBA-3, including singular reactivity against NS5, may be associated with the presence of detectable levels of HCV RNA in clinical patients but not necessarily in blood donors.

Serum HCV-RNA levels in patients with chronic hepatitis C: Correlation with histological features

BACKGROUND AND STUDY AIMS

Liver disease in chronic hepatitis C virus (HCV) infection ranges from minimal lesion to liver cirrhosis and sometimes eventually evolving hepatocellular carcinoma. Whether and how HCV determines the different clinical and histological manifestation of the disease is not fully understood. It has not been clearly elucidated whether the extent of liver injury induced by HCV is influenced mainly by direct cytopathic damage or by an immune-mediated response against HCV-infected hepatocytes. The aim of this study is to verify whether the amount of virus in individual patient's serum could be related to the severity of liver injury.

PATIENTS AND METHODS

This study was carried out in the Gastroenterology and Hepatology Teaching Hospital, Medical City, Baghdad. Serum levels of HCV-RNA were measured in 27 patients with chronic HCV using b-DNA assay. Core liver biopsies of the patients were evaluated according to Ishak histological activity index system.

RESULTS

The serum HCV RNA concentrations in the patients ranged from 3.2×10(3) to 1.2×10(7)copies/ml. In all patients no correlation was observed between the variable levels of viraemia and the age of the patients. Furthermore no correlations were observed between the serum HCV RNA concentrations and the biochemical liver function test levels: Total serum bilirubin, AST, ALT, and alkaline phosphatase. Histologically; patients were categorized into four subgroups: four patients (14.8%) had minimal activity, 17 patients (63%) had mild activity, and six patients (22.2%) had moderate activity. No significant correlation was found between viraemic levels and these histological findings or their individual components: Interface hepatitis, confluent necrosis, intralobular liver cell necrosis and portal inflammation. According to the stage of the fibrosis, the patients were categorized into seven subgroups: one patient (3.7%) with stage zero, seven patients with stage one (25.9%), four patients with stage two (14.9%), eight patients with stage three (29.6%), three patients with stage four (11.1%), two patients with stage five (7.4%), and two patients in cirrhotic stage six (7.4%). There was no correlation between the serum HCV RNA concentration and the stage of fibrosis. Hepatic steatosis was observed in 16/27 patients. It was mild in nine patients, moderate in five patients, and severe in two patients. Correlation has not been observed between the serum HCV RNA viraemic level and the severity of steatosis.

CONCLUSION

Serum HCV-RNA level does not determine the degree of hepatic injury precisely and liver biopsy is necessary to accurately evaluate the extent of liver damage.

High incidence of hepatitis C virus reinfection within a cohort of injecting drug users

A retrospective cohort study was established of injecting drug users (IDUs) to assess evidence for hepatitis C virus (HCV) protective immunity through a comparison of incidence of initial HCV infection and HCV reinfection. Incidence of initial HCV infection was determined among HCV seronegative IDUs, and HCV reinfection determined among IDUs with newly acquired HCV infection, HCV viraemia and subsequent HCV RNA clearance. Serum was available for HCV RNA analysis from stored samples taken at the time of prior blood-borne virus screening. Potential HCV reinfection was defined as a positive HCV RNA following at least one negative HCV RNA. Incidence of initial HCV infection was 17/100 person-years (95% CI, 14-20/100 person-years). The incidence of potential HCV reinfection was 42/100 person-years (95% CI, 25-61/100 person-years), and after excluding cases without a change in HCV genotype and less than three consecutive HCV RNA negative assessment, incidence of reinfection was 31/100 person-years (95% CI, 17-62/100 person-years). Following adjustment for HCV risk behaviour variables the incidence rate ratio of HCV reinfection to initial infection was 1.11 (P = 0.8). Several cases of HCV reinfection appear to have developed persistent infection.

Hepatitis C virus load and survival among injection drug users in the United States

Persons chronically infected with hepatitis C virus (HCV), some of whom may be coinfected with HIV and human T-lymphotropic virus type II (HTLV-II), are at high risk for end-stage liver disease (ESLD). We evaluated whether ESLD death was associated with premorbid HCV RNA level or specific HCV protein antibodies among persons with or without HIV/HTLV-II coinfection in a cohort of 6,570 injection drug users who enrolled in 9 US cities between 1987 and 1991. We compared 84 ESLD descendents and 305 randomly selected cohort participants with detectable HCV RNA, stratified by sex, race, HIV, and HTLV-II strata. Relative hazard (RH) of ESLD death was derived from the proportional hazard model. Risk of ESLD death was unrelated to the intensity of antibodies against the HCV c-22(p), c-33(p), c-100(p), and NS5 proteins, individually or combined, but it increased with HCV RNA level (RH(adj) = 2.26 per log(10) IU/mL, 95% CI: 1.45-5.92). The association between HCV RNA level and ESLD death remained significant after adjustment for alcohol consumption (RH(adj) = 2.57 per log(10) IU/mL, 95% CI: 1.50-8.10). Deaths from AIDS (n = 45) and other causes (n = 43) were unrelated to HCV RNA (RH(adj)= 1.14 and 1.29 per log(10) IU/mL, respectively). HIV infection was not associated with ESLD risk in multivariate analyses adjusted for HCV RNA. Men had an increased risk of ESLD death in unadjusted analyses (RH = 1.92, 95% CI: 1.15-3.56) but not in multivariate analysis (RH(adj) = 0.98, 95% CI: 0.48-2.88). Non-black patients were at increased risk for ESLD death (RH(adj)= 2.76, 95% CI: 1.49-10.09). In conclusion, HCV RNA level is a predictor of ESLD death among persons with chronic HCV infection.

Design options for molecular epidemiology research within cohort studies

Past discussions of the relative strengths of nested case-control and case-cohort designs have not fully considered cohorts with stored biological samples in which biomarker analyses are planned. Issues related to biomarker analyses can affect an investigator's choice of design and the conduct of these two designs. The key issues identified are effects of analytic batch, long-term storage, and freeze-thaw cycles on biomarkers. In comparison with the nested case-control design, the case-cohort design is less able to handle these challenges. Problems arise because most implementations of the case-cohort design do not allow for simultaneous evaluation of biomarkers in cases and reference group members, and there is no matching. By design, the nested case-control study controls for storage duration and the batching of biological samples from cases and controls is logistically simple. The allowance for matching also means that subjects can be matched on the number of freeze-thaw cycles experienced by the biological sample. However, the matching generates complex data sets that can be more difficult to analyze, and the costly biomarker data generated from the controls has few uses outside of testing the specific hypotheses of the study. In addition, because the same subject can serve as a control and a case, or multiple times as a control, biomarker analyses and sample batching can be more complex than initially anticipated. However, in total, of the two designs, the nested case-control study is better suited for studying biomarkers that can be influenced by analytic batch, long-term storage, and freeze-thaw cycles.

Hepatic steatosis in chronic hepatitis B and C: predictors, distribution and effect on fibrosis

BACKGROUND/AIMS

Chronic hepatitis B (CHB) and C (CHC) are commonly associated with hepatic steatosis. The aims of this study were to investigate predictors of hepatic steatosis, and their impact on inflammation and fibrosis in CHB and CHC.

METHODS

Consecutive patients with either CHB or CHC who underwent a liver biopsy at The Alfred Hospital between April and September 2002 were included. Histological analysis of liver biopsies was performed by two hepatopathologists blinded to the clinical data.

RESULTS

Ninety-one patients were analysed including 17 patients with CHB and 74 with CHC. CHC genotype 3, C-peptide, glucose and waist circumference were independent predictors of extent of Brunt steatosis grade, while CHC genotype 3, C-peptide and waist circumference were independent predictors of microvesicular steatosis grade. Alcohol intake and age were predictors of hepatic fibrosis. There was a trend toward a correlation between both Brunt steatosis and microvesicular steatosis grades and fibrosis progression rate in CHC genotype non-3.

CONCLUSIONS

Hepatic steatosis is common in chronic hepatitis B and C, and is associated with waist circumference, glucose, C-peptide and chronic hepatitis C genotype 3. Steatosis grade appears to relate to hepatic fibrosis progression rate in chronic hepatitis C genotype non-3.

Performance of hepatitis C virus core antigen immunoassay in monitoring viral load after liver transplantation

BACKGROUND

In the liver transplantation (LTx) setting, there are several situations where measurement of hepatitis C virus (HCV)-RNA concentration may provide relevant information. However, HCV-RNA quantification is expensive and not routinely available in all laboratories. An assay to quantify total HCV core antigen in serum has been recently developed. The aim of this study was to compare the performance of HCV-RNA and HCV core antigen determination in a cohort of 116 HCV-infected patients who underwent LTx.

METHODS

HCV-RNA and HCV core antigen concentrations were determined in serum samples (n=435) obtained before LTx and at weeks 4, 12, and 48 after LTx.

RESULTS

There was an excellent correlation between HCV-RNA and HCV core antigen levels (r=0.802 P<0.001), with an equivalence of 9,900 IU/mL of HCV-RNA per pg/mL of HCV core antigen. The determination of core antigen was linear in samples containing between 20,000 and 2,500,000 IU/mL of HCV-RNA and highly reproducible (mean coefficient of variation, 15%). Overall, HCV core antigen tested positive in 378 (92%) of 410 samples with detectable HCV-RNA (>600 IU/mL); the percentage increased to 98% in samples taken later than 4 weeks after LTx. In fact, almost all samples (369 of 375 [98.4%]) with HCV-RNA levels higher than 20,000 IU/mL were positive for HCV core antigen, whereas 56 of 57 samples with undetectable core antigen had HCV-RNA levels below 50,000 IU/mL.

CONCLUSIONS

The performance of total HCV core antigen immunoassay is appropriate for monitoring viral load in HCV-infected patients undergoing LTx and might be considered a useful alternative to HCV-RNA testing.

The role of core antigen detection in management of hepatitis C: a critical review

Several assays in research format and two commercial assays for the detection of hepatitis C virus (HCV) core protein or HCV core antigen have been developed in recent years. In order to elucidate the role and significance of HCV core antigen detection in the diagnosis and management of hepatitis C, we reviewed 56 studies published in peer-reviewed journals until September 2004. Evaluations in transfusion settings showed that the HCV core antigen assay detects HCV infection, similarly as nucleic acid techniques (NAT), between 40 and 50 days earlier than the current third generation HCV antibody screening assays. HCV core antigen levels closely track HCV RNA dynamics, and allow clinical monitoring of a patient's therapy, independently of HCV genotype, however, mainly in the samples with HCV RNA levels above 20,000 IU/ml. Considering the lower sensitivity of HCV core antigen detection in comparison to NAT, the HCV core antigen assay is not practical for the determination of the end of treatment response and sustained viral response, but could be useful for the determination of early viral response in the pegylated interferon-alpha and ribavirin treated patients infected with HCV genotype 1. The HCV core antigen detection is a viable tool for study of hepatitis C pathogenesis. The HCV core antigen can be used as a marker of HCV replication in anti-HCV positive individuals in the areas of the world that cannot afford NAT and/or in the settings that are not equipped or competent to perform HCV RNA testing. Because the manufacturer of HCV core antigen assays recently stopped an active marketing of these assays in several countries, it will, unfortunately and probably, never be possible to determine the actual potential and usefulness of HCV core antigen testing in the management of hepatitis C.

Benefit of hepatitis C virus core antigen assay in prediction of therapeutic response to interferon and ribavirin combination therapy

A highly sensitive second-generation hepatitis C virus (HCV) core antigen assay has recently been developed. We compared viral disappearance and first-phase kinetics between commercially available core antigen (Ag) assays, Lumipulse Ortho HCV Ag (Lumipulse-Ag), and a quantitative HCV RNA PCR assay, Cobas Amplicor HCV Monitor test, version 2 (Amplicor M), to estimate the predictive benefit of a sustained viral response (SVR) and non-SVR in 44 genotype 1b patients treated with interferon (IFN) and ribavirin. HCV core Ag negativity could predict SVR on day 1 (sensitivity = 100%, specificity = 85.0%, accuracy = 86.4%), whereas RNA negativity could predict SVR on day 7 (sensitivity = 100%, specificity = 87.2%, accuracy = 88.6%). None of the patients who had detectable serum core Ag or RNA on day 14 achieved SVR (specificity = 100%). The predictive accuracy on day 14 was higher by RNA negativity (93.2%) than that by core Ag negativity (75.0%). The combined predictive criterion of both viral load decline during the first 24 h and basal viral load was also predictive for SVR; the sensitivities of Lumipulse-Ag and Amplicor-M were 45.5 and 47.6%, respectively, and the specificity was 100%. Amplicor-M had better predictive accuracy than Lumipulse-Ag in 2-week disappearance tests because it had better sensitivity. On the other hand, estimates of kinetic parameters were similar regardless of the detection method. Although the correlations between Lumipulse-Ag and Amplicor-M were good both before and 24 h after IFN administration, HCV core Ag seemed to be relatively lower 24 h after IFN administration than before administration. Lumipulse-Ag seems to be useful for detecting the HCV concentration during IFN therapy; however, we still need to understand the characteristics of the assay.

[Genetic variability of hepatitis C virus in the health area of Elche (Spain). Correlation between core antigen and viral load]

We investigated the prevalence of the various genotypes of hepatitis C virus (HCV) in 281 patients evaluated between March, 2000 and March, 2002 in the health area of Elche. Of these patients, 55 were coinfected with human immunodeficiency virus (HIV). The genotype was related to viral load and the co-existence of HIV infection. Likewise, the relationship between these parameters and the presence of the HCV core antigen was established. The results indicate that genotype 1b was the most prevalent (38.4%) followed by genotype 3a (23.1%). Patients coinfected with HIV presented fewer infections due to group 1 genotypes (p < 0.05).Patients with HIV presented a greater viral load in all the genotypes, with genotype 3 presenting a high viral load. Detection of the HCV core antigen showed a close correlation with viral load determinations. Although not yet sufficiently assessed, determination of the HCV core antigen constitutes a simple technique that could eventually contribute to improving the management of patients with chronic HCV hepatitis.