Genotype, viral load and age as independent predictors of treatment outcome of interferon-alpha 2a treatment in patients with chronic hepatitis C. Construct group

Molecular Epidemiology of HCV RNA Genotype-3 in Dhaka City, Bangladesh

Hepatitis C virus (HCV) is a causative agent that causes chronic liver diseases worldwide. It is a little, enclosed, single-stranded ribonucleic acid (RNA) virus. The recognition of the pathogenic HCV genotype is critical for the remedy of its sufferers. The aim of this study was to identify the HCV RNA genotype to decide the correct treatment of hepatitis C positive sufferers in Bangladesh. Blood samples were collected from 390 individuals and isolated RNA (60 µg) from blood plasma. Extracted RNA was used for quantitative HCV RNA, and complementary DNA (cDNA) was prepared by polymerase chain reaction (PCR) conducted by reverse transcriptase enzyme. This cDNA amplified in multiplex by RT-PCR, which was performed with specific set of primers. The HCV RNA genotype was detected 297 of 390 patients. Of the 390 test samples, 200 (51.28%) samples were from males and 190 (48.71%) were from females, with age ranging from 5 to 78 years. In all, 166 of 200 male samples and 131/190 female samples were found positive for HCV. Of these 390 participants included in the study, 213 (54.61%) were identified as genotype 3 positive, 78 (20%) as genotype 1 positive, 6 (1.53%) as genotype 6 positive, and the remaining 93 (23.85%) samples were unclassified due to low/undetected viral load. In this study, we detected the highest percentage (30.89%) of genotype 3 HCV in patients aged 51 to 60 years. The results suggested that genotype 3 HCV is frequently present in Bangladesh and it is usually responses better to interferon therapy. However, genotype 1 and 6 HCV have also been found circulating in this country, which demands longer treatments and effective control measures.

Hepatitis C viral load and genotypes among Nigerian subjects with chronic infection and implication for patient management: a retrospective review of data

Introduction

Hepatitis C Virus (HCV) is highly infectious with no currently available vaccine. Prior to treatment, it is recommended to confirm HCV infection with either quantitative or qualitative nucleic acid test. Access to these assays in Nigeria is limited but for effective management of patients, HCV viral load (VL) prior to therapy is required and genotype may be needed in some instances. This study aimed at reviewing the pattern of HCV viral load and genotype in the country, and its implication in patient management.

Methods

this was a retrospective study that involved data abstraction from an electronic database of an accredited laboratory between June 2013 and May 2017. De-linked data were abstracted from records of adult subjects with HCV VL and genotype results, these were analysed using Microsoft Excel 2010 and SPSS v20.

Results

within the study period, 346 subjects had baseline VL and 134 (38.7%) had genotype results available. Of these, 202/346 (58.4%) had detectable VL results with higher prevalence in males (64.7%) and ≥51years (42.5%) age group. The median VL among 202 subjects was 407,430 (IQR: 96,388 - 1,357,012) IU/mL. Distribution of genotypes showed that genotypes 1 and 4 had prevalence of 63.2% and 16.8% respectively.

Conclusion

genotypes 1 and 4 have the highest prevalence. A greater proportion of subjects had VL values ≤800,000 IU/mL, an indication that they are more likely to respond well to available antiviral therapy hence, access to these antivirals will greatly improve management of HCV infection in Nigeria.

The Association of Substitutions in the Hepatitis C Virus Subtype 1b Core Gene and IL28B Polymorphisms With the Response to Peg-IFNα-2a/RBV Combination Therapy in Azerbaijani Patients

BACKGROUND

The hepatitis C virus (HCV) infection has been identified as a leading cause of progressive liver diseases worldwide. Despite new treatment strategies, pegylated interferon alfa-2a (Peg-IFNα-2a), in combination with ribavirin (RBV), still represents the gold standard of therapy for hepatitis C in developing countries.

OBJECTIVES

The aim of this study was to investigate the association of substitutions in the HCV subtype 1b (HCV-1b) core protein and the rs12979860 polymorphism in the interleukin 28B gene (IL28B) with the response to Peg-IFNα-2a/RBV combination therapy in Azerbaijani patients.

PATIENTS AND METHODS

A total of fifty-one chronically HCV-1b-infected Azerbaijani patients were enrolled in this cross-sectional study from March 2010 to June 2015. After RNA extraction from pre-treatment plasma, the core region of the HCV genome was amplified using the nested reverse transcription (RT) polymerase chain reaction (PCR) method, followed by standard sequencing. In addition, genomic DNA was extracted from peripheral blood mononuclear cell (PBMC) specimens, and the rs12979860 single nucleotide polymorphism (SNP) was identified using a PCR-restriction fragment length polymorphism (PCR-RFLP) assay.

RESULTS

In this study, a significant association was observed between the non-responders and relapsers to antiviral therapy and substitutions in the HCV-1b core region at positions 43 (R43K, P = 0.047), 70 (R70Q, P < 0.001), 91 (M91L, P = 0.037), and 106 (S106N, P = 0.018). Concerning the IL28B polymorphism, the results showed that sustained virological response was significantly associated with homozygous CC patients (P = 0.009) as compared with other genotypes, while homozygous TT subjects were associated with HCV relapse after therapy (P = 0.006).

CONCLUSIONS

The data of the present study suggest that amino acid substitutions at position 43, 70, 91, and 106 in the HCV-1b core protein are correlated with the response to the Peg-IFNα-2a/RBV treatment in Azerbaijani patients with chronic hepatitis C. Moreover, host genetic polymorphisms, such as those of the IL28B locus, might be useful for predicting the responsiveness to Peg-IFNα-2a/RBV combination therapy against HCV.

Occurrence of genetic modifications in core, 5'UTR and NS5b of HCV associated with viral response to treatment

Background

It is becoming progressively more understandable that genetic variability of viruses is a major challenge in translating the laboratory findings to clinic. Genetic variability is the underlying cause of variant viral proteins which are not targetable by host immunological machinery.

Methods

500 patients were enrolled in study and amongst them, 451 patients were followed and categorized into two groups on the basis of their treatment response. Group 1 consisting of the 376 patients exhibited SVR while group 2 comprised 75 patients who were non-responders on the basis of viral load as evidenced by Real-Time PCR. Comparative sequence analysis was done between 75 non-responders and 75 responders (randomly picked from 376) by targeting three genomic regions, 5′UTR, core and NS5B and amplified products were directly sequenced and obtained sequences were cleaned, aligned and submitted to GenBank. Maximum Parsimony (MP) method was used for phylogenetic analysis and dendrograms were dragged using MEGA 5. Heterogeneity at nucleotide and amino acid level was determined using software BioEdit and DNAman while phosphorylation and N-linked glycosylation sites were determined using NetPhos 2.0 and SignalP-NN.

Results

Genotype 3 was prevalent in group 1 whereas non-responders indicated rare genotypes of Pakistan i.e. 4 and 5, genotype 6q and 6v were reported first time from Pakistan in this study. At nucleotide and amino acid level, the genetic distance and mutation, number of predicted N-phosphorylation and N-glycosylation sites was higher in group 2 as compared to group 1. Difference in percentage composition of individual amino acids was noted to be different between the two groups.

Conclusions

It can be concluded that heterogeneity both at nucleotide and amino acid level contributed in developing drug resistant phenotype. Moreover, occurrence of rare genotypes might hurdle the way to positive response of conventional treatment. Furthermore, prediction of phosphorylation and glycosylation sites could help in targeting the proper sites for drug designing.

Distribution pattern of hepatitis C virus genotypes and correlation with viral load and risk factors in chronic positive patients

OBJECTIVE

Hepatitis C virus (HCV) has emerged as a leading cause of chronic hepatitis, liver cirrhosis and hepatocellular carcinoma worldwide. The purpose of this study was to describe the distribution pattern of HCV genotypes in chronic hepatitis patients in the Campania region of southern Italy and estimate their association with risk factors and viral load.

MATERIALS AND METHODS

404 consecutive HCV ribonucleic acid-positive patients were included in the study. HCV genotyping was carried out by the HCV line probe assay test and viral load estimation by the TaqMan real-time PCR system.

RESULTS

The predominant genotype was 1 (63.6%), followed by genotype 2 (29.4%), 3 (6.2%) and 4 (0.8%). Subtype 1b was more frequent in females than in males. Conversely, genotype 3 was more frequent in males. No significant difference was observed in age distribution of HCV genotypes. Surgery and dental therapy were the most frequent risk factors for genotype 1 and intravenous drug abuse and tattooing for genotype 3. Patients with genotype 1 more frequently showed high HCV viral load when compared to those with genotypes 2 and 3.

CONCLUSION

The present study revealed that HCV genotypes 1 and 2 accounted for over 95% of all HCV infections in the Campania region, and genotype 1 was more frequently associated with a higher viral load when compared to genotypes 2 and 3.

Associations between human TRIM22 gene expression and the response to combination therapy with Peg-IFNα-2a and ribavirin in Iranian patients with chronic hepatitis C

Interferons are able to exert an antiviral effect against hepatitis C virus (HCV) infection via induction of interferon-stimulated genes (ISGs). This study tested whether differential expression of an important ISG with antiviral properties, tripartite motif 22 (TRIM22), correlates with a response to Peg-IFNα-2a/RBV combination therapy in treatment-naive patients with chronic hepatitis C. A total of 32 patients with chronic hepatitis C were enrolled in this study and received standard Peg-IFNα-2a/RBV combination therapy. HCV viral load was measured during treatment, at the end of treatment, and 6 months later to determine the treatment outcome. Quantitative real-time PCR was used to assess the expression levels of TRIM22 in peripheral blood mononuclear cells (PBMCs) of the patients before antiviral therapy. Of the 32 patients, 26 (81.3%) were males. In this study, there were 16 (50%) individuals with a sustained virologic response (SVR), and a virologic relapse was observed in the remaining half of the subjects. Testing for the presence of genomic HCV RNA in blood during therapy revealed a rapid virologic response (RVR) in 10 (31.2%) and a partial and complete early virologic response (EVR) in 8 (25%) and 24 (75%) of the cases, respectively. TRIM22 mRNA levels were significantly higher in patients with a sustained virologic response than in relapsers (P = 0.002) and in patients with a rapid virologic response than in the others (P = 0.040). No statistically significant difference was seen in the expression of TRIM22 between patients with a partial early virologic response and a complete early virologic response. This study showed that pretreatment upregulation of TRIM22 may be associated with responsiveness to Peg-IFNα-2a/RBV combination therapy.

Determination of HCV genotypes and viral loads in chronic HCV infected patients of Hazara Pakistan

Hepatitis C Virus (HCV) genotype and viral load are two significant predictive variables knowledge of which might persuade treatment decisions. The objective of the present study was to identify the distribution of different HCV genotypes circulating in the study area and to estimate viral load in chronically HCV infected patients. Out of total 305 HCV positive patients, 177 (58%) were males and 128 (42%) were females. Frequency breakup of the HCV positive patients was 169, 69, 38 and 29 from Abbottabad, Mansehra, Haripur and Battagram districts respectively. Out of the total 305 tested serum samples, 255 (83.06%) were successfully genotyped whereas 50 (16.4%) samples were found with unclassified genotypes. Among typable genotypes, 1a accounted for 21 (6.8%) 1b for 14 (4.6%), 2a for 4 (1.31%) 3a for 166 (54.42%) and genotype 3b for (8.19%). Twenty five (8.19%) patients were infected with mixed HCV genotypes. Viral load distribution was classified into three categories based on its viral load levels such as low (< 60, 0000 IU/mL), intermediate (60,0000-80,0000 IU/mL) and high (> 80,0000 IU/mL). The baseline HCV RNA Viral load in HCV genotype 3 infected patients was 50 (26.17%), 46 (24.08%) and 95 (49.73%) for low, intermediate and high categories respectively. For genotypes other than 3, these values for low, intermediate and high viral load categories were 50 (43.85), 35 (30.70) and 29 (25.43) respectively. Pre-treatment viral load in patients with untypable genotype was 19 (38.00%), 5 (20.00%) and 11 (44.00%) for low, intermediate and high viral load categories. Viral load distribution was also categorized sex wise; for males it was 58 (32.76%), 26 (14.68%) and 93 (52.54%) whereas for females it was 40 (31.25%), 34 (26.56%) and 54 (42.18%) for low, intermediate and high viral load respectively. In conclusion HCV genotype 3a is the most prevalent genotype circulating in Hazara Division like other parts of pakistan. Pre-treatment viral load is significantly high (p 0.014) in patients infected with HCV genotype 3 as compared to other genotypes.

Performance evaluation of the Abbott RealTime HCV Genotype II for hepatitis C virus genotyping

BACKGROUND

The Abbott RealTime hepatitis C virus (HCV) Genotype II (Abbott Molecular Inc.) for HCV genotyping, which uses real-time PCR technology, has recently been developed.

METHODS

Accuracy and sensitivity of detection were assessed using the HCV RNA PHW202 performance panel (SeraCare Life Sciences). Consistency with restriction fragment mass polymorphism (RFMP) data, cross-reactivity with other viruses, and the ability to detect minor strains in mixtures of genotypes 1 and 2 were evaluated using clinical samples.

RESULTS

All performance panel viruses were correctly genotyped at levels of >500 IU/mL. Results were 100% concordant with RFMP genotypic data (66/66). However, 5% (3/66) of the samples examined displayed probable genotypic cross reactivity. No cross reactivity with other viruses was evident. Minor strains in the mixtures were not effectively distinguished, even at quantities higher than the detection limit.

CONCLUSIONS

The Abbott RealTime HCV Genotype II assay was very accurate and yielded results consistent with RFMP data. Although the assay has the advantages of automation and short turnaround time, we suggest that further improvements are necessary before it is used routinely in clinical practice. Efforts are needed to decrease cross reactivity among genotypes and to improve the ability to detect minor genotypes in mixed infections.

Safety, pharmacokinetics and antiviral effect of BILB 1941, a novel hepatitis C virus RNA polymerase inhibitor, after 5 days oral treatment

Background

BILB 1941 is a potent and specific non-nucleoside inhibitor of the hepatitis C virus (HCV) RNA polymerase in vitro.

Methods

In a double-blind sequential group comparison, 96 male HCV genotype 1 patients with minimal to mild liver fibrosis (Ishak or Metavir score 0–2) were randomized (8 to active treatment and 2 to placebo per dose group) and treated with 10–450 mg BILB 1941 every 8 h over 5 days. Viral load (VL) was measured using Roche Cobas TaqMan® assays.

Results

VL decreased by ≥1 log10 IU/ml in 2/8, 2/8, 1/8, 2/7, 0/8, 2/8 and 4/5 patients on 60, 80, 100, 150, 200, 300 and 450 mg, respectively. No response was seen with placebo. HCV subtype 1b showed better response than 1a, the effect of other covariables including prior interferon treatment was not significant. NS5B population sequencing and phenotyping identified baseline samples with reduced BILB 1941 susceptibility, but did not detect an on-treatment emergence of resistant mutants. Plasma drug levels were linear until 300 mg. No serious adverse events (AEs) were reported. AEs were mainly gastrointestinal-related (most frequent diarrhoea) and frequency increased with dose. On 450 mg, all five active-treated patients discontinued (four for gastrointestinal intolerance and one for increased aspartate aminotransferase and alanine aminotransferase levels) and the trial was discontinued.

Conclusions

BILB 1941 monotherapy demonstrated antiviral activity against HCV genotype 1, but gastrointestinal intolerance precluded testing of higher doses.

Evaluation of Versant hepatitis C virus genotype assay (LiPA) 2.0

Hepatitis C virus (HCV) genotyping is a tool used to optimize antiviral treatment regimens. The newly developed Versant HCV genotype assay (LiPA) 2.0 uses sequence information from both the 5' untranslated region and the core region, allowing distinction between HCV genotype 1 and subtypes c to l of genotype 6 and between subtypes a and b of genotype 1. HCV-positive samples were genotyped manually using the Versant HCV genotype assay (LiPA) 2.0 system according to the manufacturer's instructions. For the comparison study, Versant HCV genotype assay (LiPA) 1.0 was used. In this study, 99.7% of the samples could be amplified, the genotype of 96.0% of samples could be determined, and the agreement with the reference method was 99.4% when a genotype was determined. The reproducibility study showed no significant differences in performance across sites (P = 0.43) or across lots (P = 0.88). In the comparison study, 13 samples that were uninterpretable or incorrectly genotyped with Versant HCV genotype assay (LiPA) 1.0 were correctly genotyped by Versant HCV genotype assay (LiPA) 2.0. Versant HCV genotype assay (LiPA) 2.0 is a sensitive, accurate, and reliable assay for HCV genotyping. The inclusion of the core region probes in Versant HCV genotype assay (LiPA) 2.0 results in a genotyping success rate higher than that of the current Versant HCV genotype assay (LiPA) 1.0.

Follow-up studies of treatment for hepatitis C virus infection among injection drug users

Physicians are reluctant to treat chronic hepatitis C virus (HCV) infection in active injection drug users (IDUs). An important reason for this is concern about reinfection after successful treatment. However, little is known about this apparent risk; because of lack of protective immunity, reinfection with HCV seems possible. Here, I discuss several cases of probable reinfection in IDUs, 2 of which occurred during or after successful treatment for HCV infection. In a Norwegian trial, 69 IDUs who had abstained from drug use for >or=6 months were treated for HCV infection; of these, 27 tested negative for HCV RNA at 6 months of follow-up (sustained virological response). At 5 years of follow-up, 9 (33%) of the 27 IDUs with sustained virological response had returned to drug use, but only 1 case of reinfection was observed. In another study, 395 subjects with sustained virological response were followed with yearly testing for HCV RNA. Although injection drug use was the route of HCV transmission in 40% of the subjects, only 7 (2%) experienced a late relapse of HCV infection. It has not been determined whether any of these cases were actual reinfections. Available data suggest that the rate of long-term response to treatment for HCV infection is excellent in IDUs.

A decade of trials of interferon-alpha for chronic hepatitis C. A meta-regression analysis

The most relevant randomized controlled trials of interferon-alpha (IFN) for naive patients with chronic hepatitis C (CHC) published in a decade, just before appearance of pegylated IFN trials in 2000, were included in this paper. Its purpose is to review the relationship between sustained biochemical response in active versus control group versus usual clinical variables as IFN regimens, cirrhosis, genotype and versus less frequently addressed variables as funding, methodological quality or location of principal author. Meta-analysis estimates of global treatment effect varied according to trial design: group 1=IFN versus placebo/no treatment, 32 RCTs, 2499 pts, OR 9.5 (6.3-14.2); group 2a=comparison of IFN schedules, 43 RCTs, 7454 pts, OR 1.6 (1.4-1.9); group 2b=IFN+other drugs versus standard IFN, 30 RCTs, 4737 pts, OR 2.0 (1.6-2.6). Fixed effects (arm-level) meta-regression on the complete data set (171 arms, 10,580 pts) revealed that sustained response was most likely in experimental arms of IFN+ribavirin or other drugs (OR 2.4), arms using yearly schedule (OR 2.0), trial principal author from Asia (OR 1.7), trial sample size >200 (OR 1.4) and arms enrolling less than 50% of cirrhotics (OR 1.3). Moreover, focus was on some significant interactions too, as the effect of trial's quality interacting to the recorded funding (more benefit if no-profit, less if for-profit) and the effect of trial funding interacting to the location of first author (more benefit if from Asia). Three main effects (experimental arm, cirrhosis, funding) and one interaction (funding*location of principal author) explained 31% of between study variability in a random-effect meta-regression. In a subgroup analysis on a data set including available information on HCV genotype (93 arms, around 7000 pts), meta-regression revealed that genotype 1 or 4 less than 50% per arm and specialistic journal were significant predictors of either biochemical (transaminases) or virological (HCV-RNA) sustained response, in a model including the same main effects identified in the complete data set analysis. Finally, although mostly captured by different IFN regimens along time, heterogeneity of effect in a large set of (not-pegylated) IFN trials was also explained by HCV genotype and variables of quality and reporting, such as trial's principal author from Asia.

Dynamic decision analysis to determine optimal treatment duration in chronic hepatitis C

BACKGROUND

Current guidelines for stopping treatment of chronic hepatitis C are based on hepatitis C ribonucleic acid measurements at 12 and 24 weeks.

AIM

To explore an alternative approach for making individualized recommendations about treatment duration, based on simple alanine aminotransferase tests and on cost-per-cure.

METHODS

We analysed individual patient data from 13 randomized, controlled trials with interferon alone or combined with ribavirin. Using multiple logistic regression, we built a model that estimated the probability of sustained virological response for treatment durations of 24 and 48 weeks. Decisions to prolong treatment were based on an increase in probability of sustained virological response. If the increase was 10%, the cost-per-cure became decisive with a limit of 50,000.

RESULTS

Noncirrhotics with genotype 2 or 3 did not benefit when treatment was continued beyond 24 weeks. Sustained virological response rates in cirrhotic patients increased by 14-47% if treatment was continued up to 48 weeks. In noncirrhotic genotype 1 or 4 patients who had elevated alanine aminotransferase levels at week 4, the probability of sustained virological response increased by <10% if treatment was continued up to 48 weeks; the cost-per-cure for these patients would exceed 50,000.

CONCLUSION

The dynamics of alanine aminotransferase levels and cost-per-cure provides a useful alternative to determine the duration of therapy in chronic hepatitis C.

Review article: indicators and predictors of response to anti-viral therapy in chronic hepatitis C

The complications of chronic hepatitis C, including cirrhosis and hepatocellular carcinoma, are expected to increase dramatically world-wide over the next 10-20 years. Immunomodulatory/anti-viral therapy, employing interferon alfa both alone and in combination with ribavirin, affords the only effective treatment for hepatitis C. Accurate early prediction of response to interferon therapy may decrease or eliminate unnecessary or ineffective treatment, permit greater flexibility in tailoring therapy on an individual basis, and enhance the cost-effectiveness of treatment. Liver biopsy provides valuable information about the baseline severity and subsequent progression of hepatitis C. Severe fibrosis or cirrhosis on the pre-treatment liver biopsy is associated with decreased response rates. The measurement of viral RNA levels and genotyping may be used to optimize individual patient treatment. Genotype non-1 and a low viral load are the most significant pre-treatment indicators of sustained virological response. The most reliable predictor of a poor virological response is continued seropositivity for viral RNA during therapy. Therefore, a decision to stop or continue treatment can be based on a positive viral RNA test at 12 weeks for interferon-naive patients receiving interferon or pegylated interferon therapy.

New disc-based technologies for diagnostic and research applications

The role of genotypic analysis in disease diagnostics and drug response assessment is continually expanding. New genomic discoveries combined with new, novel technologies may provide a greater range of testing capabilities in the near future. We describe the application of nanotechnology, in which DNA microarrays have been placed in a microchannel environment that can be read and analyzed in an optical (CD/DVD) disc drive system. The potential exists to combine molecular and immunological applications together into a rapid, low-cost, high-capacity screening platform. The relevance of this technology is discussed in respect to infectious agent detection, pharmacogenomics, neurogenomics and genetic variations associated with neurologic diseases.

Molecular diagnosis of influenza

The past decade has seen tremendous developments in molecular diagnostic techniques. In particular, the development of PCR technology has enabled rapid and sensitive viral diagnostic tests to influence patient management. Molecular methods used directly on clinical material have an important role to play in the diagnosis and surveillance of influenza viruses. Molecular diagnostic tests that allow timely and accurate detection of influenza are already implemented in many laboratories. The combination of automated purification of nucleic acids with real-time PCR should enable even more rapid identification of viral pathogens such as influenza viruses in clinical material. The recent development of DNA microarrays to identify either multiple gene targets from a single pathogen, or multiple pathogens in a single sample has the capacity to transform influenza diagnosis. While molecular methods will not replace cell culture for the provision of virus isolates for antigenic characterisation, they remain invaluable in assisting our understanding of the epidemiology of influenza viruses.

To interfere and to anti-interfere: the interplay between hepatitis C virus and interferon

As popular strategies used by numerous viruses, interception of interferon (IFN) signaling and inhibition of IFN-induced antiviral functions allow viruses to evade the host immune response and set up successful infections. Hepatitis C virus (HCV), the leading cause of chronic liver disease worldwide and a major public health hazard, causes persistent infection in the majority of infected individuals. IFN-based therapies, currently the only ones available for HCV infection, have been unable to eliminate viral infection in the majority of patients, and many studies suggest that HCV possesses mechanisms to antagonize the IFN-induced antiviral response. Multiple viral, host, and IFN-associated factors have been implicated in the interplay between HCV and IFN. Two viral proteins, NS5A and E2, became the focus of much attention and extensive study because of their abilities to inhibit IFN-induced, double-stranded RNA-activated protein kinase (PKR), a major mediator of the IFN-induced biologic response, and to perturb the IFN signaling pathway. In this review, we discuss the significance of the interferon sensitivity determining region (ISDR) within NS5A, which has been the subject of intense debates. In addition, we discuss the potential mechanisms by which NS5A interferes with IFN signaling and the current working models. Further understanding of the molecular mechanisms underlying the interaction between HCV and IFN will likely facilitate improvement of current IFN-based therapies and development of novel treatments for the HCV pandemic. Future HCV research will benefit from both the development of efficient, convenient model systems for viral propagation, and the utilization of high throughput, genomic-scale approaches.

Genetic diversity and models of viral evolution for the hepatitis C virus

In this review we discuss the application of theoretical frameworks to the interpretation of viral gene sequence data, with particular reference to the hepatitis C virus (HCV). The increasing availability of such data means that it is now possible (and necessary) to proceed from simple qualitative models of viral evolution, to more quantitative frameworks based on statistical inference, notably population genetics and molecular phylogenetics. We argue that these approaches are invaluable tools to the virologist and are essential for understanding the dynamics of viral infection and the outcome of therapeutic strategies. We use several recent HCV data-sets to illustrate the methods.

Interferon and ribavirin as frontline treatment for chronic hepatitis C infection in thalassaemia major

Hepatitis C virus (HCV) infection is common in transfusion-dependent thalassaemia. The clinical usefulness of 12-month treatment, using interferon alpha 3 MIU/m2 thrice weekly and oral ribavirin 16 mg/kg/d, was evaluated in 18 previously untreated thalassaemia patients. The median age at start of treatment was 16 years (range 7-29). Fourteen were infected with genotype 1b and 4 with genotype 6a. The sustained biochemical and virological response rates 6 months after stopping treatment were both 72.2%. Blood consumption was temporarily increased by 30% due to ribavirin-associated haemolysis. This study demonstrated a high, sustained response rate to combination treatment despite infection with genotype 1b.

Raised serum ferritin predicts non-response to interferon and ribavirin treatment in patients with chronic hepatitis C infection

BACKGROUND/AIM

Previous studies have indicated that response to interferon therapy is inversely proportional to the amount of body iron stores. We have studied the relationship between serum ferritin, transferrin saturation, liver iron, presence of HFE-C282Y gene mutation and response to treatment in patients with chronic hepatitis C infection.

METHODS

Two hundred and fifty-six naive, HCV-RNA positive patients (60% males, median age 38 years, range 21-70) were treated with interferon and ribavirin for 6 months. Iron indices and the presence of the C282Y mutation were measured. In 242 (94%) patients iron deposition were determined by Perls staining method. Patients with negative HCV-RNA at 6 months after the end of treatment were defined as sustained viral responders.

RESULTS

Non-responders (n = 127) had significantly higher median s-ferritin values compared with sustained viral responders (130 microg/L vs. 75 microg/L P < 0.001). There was no difference in transferrin saturation among the two response groups. Only 23% (4/7) of patients with Perls grade 1 in liver biopsies responded to treatment vs. 54% (122/225) patients without iron deposition (P = 0.02), however, 10/13-non-responders had HCV genotype one. Two patients (0.8%) were homozygous for the C282Y mutation, 36 patients were heterozygous (14%). Among mutation carriers 26/38 achieved sustained response compared with 102/216 non-carriers (68% vs. 48%, P = 0.02). In a multivariate analysis s-ferritin (P = 0.030) and C282Y carrier status (P = 0.012) remained independent predict of sustained response.

CONCLUSIONS

Raised s-ferritin values predicate non-response to interferon-ribavirin therapy in hepatitis C patients. Response rate in C282Y mutation carriers seems greater than in non-carriers.

Distribution of HCV genotypes among risk groups in Serbia

Blood samples from 190 patients that were anti-hepatitis C virus (HCV) positive were genotyped and 165 were found to contain HCV-RNA. Genotyping was performed by PCR based on type-specific primers (117 isolates) and LiPA test (48 isolates) and verifying by sequencing. In Serbia, the most frequent genotype was 1b (49.1%), followed by genotype 3 (21.2%) and genotype 1a (8.5%). The frequency of genotypes 2 and 4 was below 5% and mixed infections were encountered in 9.1% of cases. Distribution of genotypes was monitored in different risk groups: intravenous drug abusers, patients under blood transfusion, patients with previous history of surgery, patients undergoing hemodialysis and those with unknown risk factors. Genotype distribution is essentially the same in all the groups, except for the patients undergoing hemodialysis and those with previous history of surgery where significant difference exists compared with the group with unknown route of transmission (p < 0.001 and p < 0.05, respectively). There exists significant age-dependent genotype 3 distribution in Serbian population (p < 0.01).

Effect of HCV viral dynamics on treatment design: lessons learned from HIV

Viral load measurements provide an indication of viral replication, and thereby serve as a valuable tool to guide the initiation of therapy and subsequent changes. Plasma human immunodeficiency viral load strongly predicts the rate of decrease in CD4+ lymphocyte count, and progression to AIDS and death. Furthermore, the efficacy of antiretroviral therapy can be assessed by monitoring changes in plasma human immunodeficiency viral load. Similarly, viral load provides valuable information about the natural history of the hepatitis C virus infection. Hepatitis C viral load can be used to predict the likelihood of response to standard interferon-alpha treatment and other interferon-alpha regimens and to monitor treatment efficacy. Increased understanding of the natural history of the hepatitis C virus infection and the nature of resistance to interferon-alpha therapy suggests that effective treatment regimens must maintain serum levels of interferon-alpha. Ideally, interferon-alpha serum levels should provide constant pressure on the virus and should prevent viral rebound, thereby avoiding continued viral replication and minimizing the potential for emergence of resistant quasi-species. Current regimens designed to address these points include early aggressive intervention, combination drug regimens, prolonged maintenance, and novel interferons. By enabling the design and rapid assessment of new treatment regimens, viral load measurement will revolutionize the clinical management of the hepatitis C virus infection, as it has the HIV.

Quantitative analysis of specific Th1/Th2 helper cell responses and IgG subtype antibodies in interferon-alpha-treated patients with chronic hepatitis C

This study aimed to characterise the immune mechanisms relevant to viral clearance in interferon (IFN)-alpha-treated chronic hepatitis C virus (HCV) infection. Proliferative responses of peripheral blood mononuclear cells from sustained complete IFN-alpha therapy responders (n = 8), nonresponders (n = 13), untreated patients (n = 10), and healthy controls (n = 5) were measured retrospectively upon stimulation with recombinant HCV-antigens (core, helicase, NS3, NS4, and NS5) and the secretion of IFN-gamma and interleukins (IL-4, IL-5, IL-10, and IL-12) were tested by ELISA. Furthermore, IFN-gamma as well as IL-10 secreting CD4+ T cells were quantitated by intracellular cytokine staining. Anti-HCV core and NS3-specific IgG subclass antibodies were quantitated in the corresponding patient sera. Sustained therapy responders had more frequent and stronger NS3 and helicase-specific cellular immune responses than nonresponders, untreated HCV patients and healthy controls. Independent from therapy outcome HCV-stimulated T cells in IFN-alpha treated patients secreted preferentially IFN-gamma The Th2 cytokines IL-4 and IL-10 were even decreased in nonresponders, while the IL-12 secretion was not influenced. With respect to the humoral immune response sustained complete responders showed significantly reduced IFN-gamma independent anti-HCV-core and -NS3 IgG1 antibody synthesis. In conclusion, vigorous NS3-specific T-helper cell responses were associated with viral clearance in IFN-alpha recipients; however, the cytokine and antibody analysis argues against a Th1/Th2 imbalance as a major factor that influence the therapy outcome.

African Americans with genotype 1 treated with interferon for chronic hepatitis C have a lower end of treatment response than Caucasians

African Americans as a group have a higher incidence of chronic hepatitis C (CHC) than Caucasians but are often under-represented in clinical trials used to define response rates to interferon therapy. The aim of this study was to compare African Americans with Caucasians with respect to end-of-treatment response to interferon. This retrospective study had 61 African Americans and 49 Caucasians with CHC. All patients were treated for at least 12 weeks with interferon-alpha2b (Intron A) thrice weekly. End-of-treatment response was defined as three consecutive nondetectable HCV RNA measurements at least 1 month apart. Sustained response was defined as a negative serum HCV RNA 6 months after end of treatment. Of the 110 patients, 19 achieved an end-of-treatment response (17%) but only four achieved a sustained response (4/110=4%). Of the patients achieving a sustained response, one was genotype 1 (male Caucasian), three were genotype 2/3 with four patients having no follow-up information. The end-of-treatment response was 7% for patients with genotype 1 and 71% for genotype non-1 (P < 0.005 for genotype non-1). The end-of-treatment response was significantly higher in Caucasians (14/49=31%) compared with African Americans (5/61=8%; P < 0.05). A lower response rate in African Americans with genotype 1 in contrast to Caucasians was the primary reason for the difference in end-of-treatment response (1/45=2% vs. 5/33=15%, P < 0.05). Hence, interferon treatment resulted in a poor sustained response rate in the group of patients representative of the urban populations with the highest prevalence of hepatitis C. A genotype other than type 1 was the strongest predictor of end-of-treatment response in patients treated but over 86% of patients in this urban clinic were genotype 1. Caucasians were more likely to respond than African Americans, especially in patients with genotype 1.

Genetic characterization of hypervariable region 1 in patients chronically infected with hepatitis C virus genotype 2

The hypervariable region 1 (HVR1) has been most reliably identified in the genome of HCV genotype 1 isolates and thought to possibly play a role in immune evasion and development of chronic infection. There are few studies, however, of other HCV genotypes to determine if they also have such a hypervariable region present, and it is unclear whether or not there is any genotype-dependent difference in the genetic characteristics of HVR1. We determined the nucleotide sequence of 5' end of E2/NS1 region of the HCV genome spanning HVR1 of multiple genotype 1 and 2 HCV isolates and carried out a detailed genetic analysis. Similarity plots identified two hypervariable regions within the genotype 2 sequences, a larger one corresponding to HVR1 as well as a smaller 27-nucleotide region of hypervariability. The synonymous substitutions per synonymous site (ds) was greater than nonsynonymous substitutions per nonsynonymous site (dn) within genotype 1 group whereas dn and ds were similar in the genotype 2 group. Analysis of amino acid sequences revealed several conserved sites across genotype 1 and 2 (amino acid numbers 2,6, 20 and 26) and overall similar hydropathic profiles were found within two genotypes. Still, despite the hypervariability, the HVR1 showed a genotype-specific phylogenetic clustering. Thus, HVR1 appears to be conserved between genotypes in keeping with it having an important survival function. Genotype 2 appears to have a greater rate of nonsynonymous substitutions within HVR1, suggesting a greater positive evolutionary pressure.

Genotype and viral load as prognostic indicators in the treatment of hepatitis C

Interferon-alpha (IFN-alpha), either alone or in combination with ribavirin, is the standard treatment for patients with hepatitis C. However, most patients do not achieve a sustained remission with this treatment regimen. A number of studies have demonstrated that genotype, baseline viral load and/or a decrease in viral load early after treatment induction are the major predictive factors for response to treatment with IFN. Patients with hepatitis C virus (HCV) genotype 1 are more resistant to treatment with IFN, whereas low viral load at baseline and a marked decline in the HCV RNA level during the first 2-12 weeks of IFN therapy are associated with enhanced treatment efficacy. These variables could potentially be used to develop treatment algorithms that tailor therapies for specific clinical situations. Continued development and refinement of such algorithms would facilitate both the selection of patients who are most likely to benefit from therapy and the development of optimal treatment regimens for different patient groups. Predictive factors will also enable clinicians to identify subsets of patients who are not expected to respond well to current treatment. The development of new delivery methods for IFN that produce sustained antiviral pressure may provide a means of treating these previously difficult-to-treat patient groups.

Methodological issues in papers on IFN therapy: time for reappraisal

We conducted an analytical review of 194 full papers on interferon (IFN) therapy for chronic hepatitis C to evaluate current methodology (i.e. study design, criteria for evaluating the efficacy of therapy and predictors of response). Of the papers evaluated, 64 were randomized controlled trials (RCT), 40 were non-randomized controlled trials (NRCT) and 90 were observational studies (OS). The methodological analysis was focused mainly on clinical trials. The number of patients enrolled in RCT was higher compared with the number enrolled in NRCT. Uniform enrolment criteria were used in less than 50% of the trials. Only 20% of RCT and 2.5% of NRCT used criteria for defining sample size. The response rate was calculated on an intention-to-treat basis in 36 of the RCT and in 14 of the NRCT. The outcome of treatment and the criteria employed to define the response to treatment were found to be far from standardized. In 51.5% of the RCT and 42.5% of the NRCT, normalization of alanine aminotransferase (ALT) level at the end of follow-up was the only marker of response studied. Only 57.6% of the trials considered histological evidence as an important outcome. Among the clinical trials, 71.1% evaluated predictors of good response to IFN therapy. In 51% of the OS, ALT normalization by the end of follow-up was the only criterion for defining response. In conclusion, to ensure a high level of reliability in comparing or combining the results of different studies, some basic general requirements must be followed when planning trials on antiviral therapy.

HCV genotypes--role in pathogenesis of disease and response to therapy

Hepatitis C virus (HCV) shows considerable variation in its genomic structure, allowing classification into six main genotypes. Epidemiological studies have shown marked differences in genotype distribution by geographical region, and between patient groups. Improved understanding of the rate of nucleotide sequence mutation in HCV has allowed the approximate time of divergence of major genotypes to be estimated, and the origin and spread of the present epidemic of hepatitis C to be better defined. Improved methods of genotype definition over the last few years have enabled the importance of genotype in the progression of HCV-related disease and response to anti-viral therapy to be studied. Present data strongly indicates that HCV genotype is an important determinant of response to treatment, but the effect of genotype on disease progression has been harder to clarify. This is largely due to the absence of model systems of HCV infection, the epidemiological differences in patient groups infected with the different genotypes, and the lack of good prospective longitudinal clinical data. As a result of advances in methodology, and recent results of large clinical trials of combination therapy, a knowledge of HCV genotype is now central to the clinician in the management of patients with chronic hepatitis C.

Distribution of HCV genotypes among different exposure categories in Brazil

Hepatitis C virus (HCV) infection is widespread and responsible for more than 60% of chronic hepatitis cases. HCV presents a genetic variability which has led to viral classification into at least 6 genotypes and a series of subtypes. These variants present characteristic geographical distribution, but their association with different responses to treatment with interferon and severity of disease still remains controversial. The aim of this study was to investigate the patterns of distribution of HCV genotypes among different exposure categories in Brazil. Two hundred and fifty anti-HCV positive samples were submitted to HCV-RNA detection by RT-PCR and their genotype was determined by restriction fragment length polymorphism (RFLP) analysis. In addition, the genotype/subtype of 60 samples was also determined by a reverse hybridization assay. HCV 1 was the most prevalent (72.0%), followed by type 3 (25.3%), HCV 2 (2.0%) and HCV 4 (0.7%). The HCV genotype distribution varied among the different exposure categories, with HCV 1 being more frequent among blood donors, hemophiliacs and hemodialysis patients. A high frequency of HCV 3 was observed in cirrhotic patients, blood donors from the South of Brazil and injecting drug users (IDUs). The general distribution of the HCV genotype in Brazil is similar to that in other regions of the world.

Renal manifestations of hepatitis C infection

Hepatitis C is an important cause of renal disease, and renal complications may be the presenting manifestation of hepatitis C infection. About half of patients present with evidence of renal insufficiency, and up to one quarter present with nephrotic syndrome. Others present with proteinuria or evidence of diminished renal function. The pathogenesis of hepatitis C-associated renal disease remains incompletely defined, but most evidence suggests that glomerular injury results from deposition of circulating immune complexes in the subendothelium and mesangium. Membranoproliferative glomerulonephritis, with or without cryoglobulinemia, is the most common renal lesion. Interferon alpha-2b is currently the treatment of choice. However, success is limited, with many patients failing to respond or suffering relapse upon discontinuation of therapy. Studies of newer treatment modalities, such as longer courses of interferon or the use of ribavirin or immunosuppressive agents, are underway. Hepatitis C-associated renal disease may progress to end-stage renal failure requiring dialysis in about 10% of patients.

Detection of GB virus C RNA by GBV-C LCx and two PCR assays with primers from the 5' non-coding and NS5B region

The objective of this study was to compare the sensitivity of three different reverse transcriptase-polymerase chain reaction (RT-PCR) based tests, for detection of GB virus C (GBV-C) RNA. One commercial and two 'in house' RT-PCR assays were employed in the testing of serum samples from 114 chronic hepatitis C infected individuals. A part of the 5' non-coding region (5'NCR) of the GBV-C genome was amplified by the GBV-C LCx assay (Abbott) and one of the 'in house' RT-PCR tests. In the other 'in house' RT-PCR a segment of the NS5B region was amplified. The 'in house' assays included the use of internal controls that were co-amplified with use of the same outer PCR primers as the virus targets. The GBV-C LCx from Abbott and 5'NCR 'in house' PCR tests detected 28 and 27 GBV-C positive individuals, respectively. The sample positive only in the LCx test was confirmed by the 'in house' 5'NCR RT PCR using an increased virus input. In comparison, the NS5B 'in house' PCR test detected 24 of the GBV-C positive samples. One sample showed no amplification of internal controls/virus target in the 5'NCR 'in house' PCR and another samples was amplification negative in the NS5B PCR. The PCR assays with primers from the 5'NCR of the virus genome e.g. the GBV-C LCx, were more sensitive compared with RT-PCR using primers from the NS5B region. The GBV-C LCx seemed to be the most sensitive and robust assay. Internal controls included in the 'in house' assays identified two samples with failure of the amplification.

Therapy for chronic hepatitis B and C infection in haemophilia

Haemophiliacs, until recently, have been at risk of hepatitis B and C infection. Substantial numbers of patients remain persistently infected. Several lines of evidence suggest that these diseases will cause considerable morbidity unless therapy can successfully reduce viraemia and prevent disease progression. Cessation of viral replication may prevent progression to hepatic fibrosis.

Algorithmic approach to high-throughput molecular screening for alpha interferon-resistant genotypes in hepatitis C patients

This study was designed to analyze the feasibility and validity of using Cleavase Fragment Length Polymorphism (CFLP) analysis as an alternative to DNA sequencing for high-throughput screening of hepatitis C virus (HCV) genotypes in a high-volume molecular pathology laboratory setting. By using a 244-bp amplicon from the 5' untranslated region of the HCV genome, 61 clinical samples received for HCV reverse transcription-PCR (RT-PCR) were genotyped by this method. The genotype frequencies assigned by the CFLP method were 44.3% for type 1a, 26.2% for 1b, 13.1% for type 2b, and 5% type 3a. The results obtained by nucleotide sequence analysis provided 100% concordance with those obtained by CFLP analysis at the major genotype level, with resolvable differences as to subtype designations for five samples. CFLP analysis-derived HCV genotype frequencies also concurred with the national estimates (N. N. Zein et al., Ann. Intern. Med. 125:634-639, 1996). Reanalysis of 42 of these samples in parallel in a different research laboratory reproduced the CFLP fingerprints for 100% of the samples. Similarly, the major subtype designations for 19 samples subjected to different incubation temperature-time conditions were also 100% reproducible. Comparative cost analysis for genotyping of HCV by line probe assay, CFLP analysis, and automated DNA sequencing indicated that the average cost per amplicon was lowest for CFLP analysis, at $20 (direct costs). On the basis of these findings we propose that CFLP analysis is a robust, sensitive, specific, and an economical method for large-scale screening of HCV-infected patients for alpha interferon-resistant HCV genotypes. The paper describes an algorithm that uses as a reflex test the RT-PCR-based qualitative screening of samples for HCV detection and also addresses genotypes that are ambiguous.

The effect of treatment with alpha-interferon on hepatitis G/GBV-C viraemia. The CONSTRUCT Group

BACKGROUND

Hepatitis G virus (HGV) or GBV-C is frequently detected in patients co-infected with hepatitis C virus (HCV). This study investigated host and virologic factors influencing the response to HGV/GBV-C to alpha-interferon treatment.

METHODS

HGV/GBV-C was detected and quantified by nested polymerase chain reaction. The influence of variables such as liver biopsy appearance, liver function abnormalities, and response of HCV to interferon treatment was monitored.

RESULTS

Fourteen of the 25 HGV/GBV-C-infected patients treated with interferon (3-6 MIU three times a week for 6 months) became non-viraemic during treatment, although all relapsed after treatment withdrawal at 6 months, with no net change in virus load between 0 and 12 months.

CONCLUSIONS

Predictive factors for clearance of HGV/GBV-C viraemia by interferon were pre-treatment severity of liver disease (median Knodell score of 4, compared with 7 for non-responders; P = 0.030) and alanine aminotransferase levels (median, 114, 182 for non-responders; P = 0.039). Clearance was associated with the treatment response of HCV. Nine of 13 who cleared HGV/GBV-C also cleared HCV, compared with 3 of 11 HGV/GBV-C non-responders; P = 0.05). The shared susceptibility of HGV/GBV-C and HCV to interferon treatment suggests a link between the mechanism of clearance of the two viruses.