Clinical use of hepatitis C virus tests for diagnosis and monitoring during therapy

Developments in the HCV Screening Technologies Based on the Detection of Antigens and Antibodies

Hepatitis C virus (HCV) accounts for 15%-20% of cases of acute infection, and chronic HCV infection is developed in about 50%-80% of HCV patients. Unfortunately, due to the lack of proper medical care, difficulty in screening for HCV infection, and lack of awareness resulted in chronic HCV infection in 71 million people on a global scale, and about 399,000 deaths in 2016. It is crucial to recognize that the effective use of antiviral medicines can cure more than 95% of HCV infected people. The Global Health Sector Strategy (GHSS) aim is to reduce the new HCV infections and the HCV associated mortality by 90% and 65%, respectively. Therefore, the methods that are simple, yet powerful enough to detect HCV infections with high sensitivity, specificity, and a shorter window period are crucial to restrain the global burden of HCV healthcare. This article focuses on the technologies used for the detection of HCV in clinical specimens.

Genotyping & diagnostic methods for hepatitis C virus: A need of low-resource countries

Hepatitis C virus (HCV) infection is a blood borne and transfusion-transmitted infection (TTI). It has emerged as one of the major health challenges worldwide. In India, around 12-18 million peoples are infected with HCV, but in terms of prevalence percentage, its looks moderate due to large population. The burden of the HCV infection increases due to lack of foolproof screening of blood and blood products before transfusion. The qualified screening and quantification of HCV play an important role in diagnosis and treatment of HCV-related diseases. If identified early, HCV infection can be managed and treated by recently available antiviral therapies with fewer side effects. However, its identification at chronic phase makes its treatment very challenging and sometimes ineffective. The drugs therapy for HCV infection treatment is also dependent on its genotype. Different genotypes of HCV differ from each other at genomic level. The RNA viruses (such as HCV) are evolving perpetually due to interaction and integration among people from different regions and countries which lead to varying therapeutic response in HCV-infected patients in different geographical regions. Therefore, proper diagnosis for infecting virus and then exact determination of genotype become important for targeted treatment. This review summarizes the general information on HCV, and methods used for its diagnosis and genotyping.

Hepatitis C virus: Screening, diagnosis, and interpretation of laboratory assays

An estimated 3% of the world population is infected with Hepatitis C virus (HCV), a hepatotropic RNA virus, transmitted primarily via the blood route. The major modes of transmission of the virus include injection drug use, unsafe injection practices, blood transfusion etc. HCV causes chronic hepatitis in about 80% of those infected by it. The mainstay in diagnosing infection with HCV is to initially screen high risk groups for antibodies to HCV (anti-HCV). The inclusion of serum to cut-off ratio (S/CO) in recent guidelines is helpful in deciding the supplemental assay to be used to confirm initially reactive screening results. Nucleic acid amplification tests (NAT) are used as confirmatory tools, and also to determine viral load prior to initiating treatment. Quantitative NAT has replaced qualitative assays. Genotyping is an important tool in clinical management to predict the likelihood of response and determine the optimal duration of therapy. The impact of this infection has begun to emerge in India. The problem of professional blood donation despite an existing law against it, and flourishing unsafe injection practices, are potential sources for the spread of hepatitis C in our country. All health care practitioners need to understand how to establish or exclude a diagnosis of HCV infection and to interpret the tests correctly. In the absence of a preventive or therapeutic vaccine, and also of post-exposure prophylaxis against the virus, it is imperative to diagnose infection by HCV so as to prevent hepatic insult and the ensuing complications that follow, including primary hepatocellular carcinoma (HCC). This review aims to help blood bank staff regarding options for diagnosis and management of donors positive for HCV.

Dried blood spot for hepatitis C virus serology and molecular testing

We investigated the performance of dried blood spots (DBS) in hepatitis C virus (HCV) diagnosis using modified commercial tests. Paired DBS and serum samples were collected from 200 patients: 100 patients with anti-HCV antibodies (anti-HCV), including 62 patients with detectable serum HCV RNA, and 100 patients without anti-HCV. The DBS sample consisted of three drops of approximately 50 microL of whole blood applied to a paper card, which was then stored at -20 degrees C within 48 hours of collection. Using the Ortho HCV 3.0 enzyme-linked immunosorbent assay kit on DBS, we observed both a specificity and sensitivity of 99% in detecting anti-HCV. HCV RNA was detected on DBS in 60/62 (97%) patients with detectable serum HCV RNA, which was then successfully quantified in 55 samples (89%) using the Cobas TaqMan HCV test. A good correlation was observed between the DBS HCV RNA concentration and the serum level (r(2) = 0.95; P < 0.001). HCV genotyping was successfully performed on DBS samples, with a full concordance between the 14 paired DBS and serum samples (genotypes 1-4).

CONCLUSION

This study presents DBS as a reliable alternative to serum specimens for detecting anti-HCV, quantifying HCV RNA and genotyping HCV. DBS may increase the opportunities for HCV testing and treatment follow-up in hard-to-reach individuals.

Approach to the management of patients with chronic hepatitis C who failed to achieve sustained virologic response

The combination of PEGIFN and RBV is the most effective therapy for patients with chronic hepatitis C. Although more than half of all patients are able to achieve SVR, a significant proportion of patients, particularly those with genotype 1, fail to have undetectable HCV RNA during treatment or relapse after completing therapy with return of detectable HCV RNA. An approach in the management of these patients is to identify factors that could have led to the NR or relapse and that could be corrected before or during a second course of therapy. Because fibrosis progression occurs slowly over decades for many patients with chronic hepatitis C, avoiding alcohol or other factors that could lead to fibrosis progression may be sufficient for the vast majority of patients. Other options that could be considered in patients who have more advanced disease include retreating with one of several new antiviral agents; retreating with higher doses of IFN or PEGIFN and RBV; or using IFN, PEGIFN, or RBV monotherapy long-term as maintenance therapy. The safety and efficacy of these approaches is being evaluated in numerous clinical trials.

Intrahepatic hepatitis C virus replication correlates with chronic hepatitis C disease severity in vivo

The role of viral factors in the pathogenesis of chronic hepatitis C is unknown. The objective of the present study was to characterize markers of hepatitis C virus (HCV) infection and replication in liver biopsy specimens obtained from 65 genotype 1-infected subjects, including 31 who were coinfected with human immunodeficiency virus (HIV), and to analyze associations between intrahepatic viral markers and hepatitis C disease severity. The percentages of liver cells harboring HCV genomes (%G) and replicative-intermediate RNAs (%RI) were evaluated using strand-specific in situ hybridization, while HCV core and NS3 antigens were assessed by immunocytochemistry. HIV-positive and HIV-negative subjects had similar mean grades and stages of liver disease and had similar indices of HCV infection and replication in liver, even though coinfected subjects had significantly shorter mean disease duration (P = 0.0003). Multivariate analysis showed that %G was not associated with grade or stage of liver disease (P = 0.5 and 0.4, respectively), while %RI was strongly associated with liver inflammation (P < 0.001), liver fibrosis (P < 0.001), and serum alanine aminotransferase levels (P = 0.01). NS3 antigen (but not core) was more frequently detected in HCV RI-positive versus RI-negative specimens (P = 0.028). These findings demonstrate a link between HCV proliferation and hepatitis C disease severity and suggest similar pathogenic mechanisms in HIV-positive and HIV-negative individuals.

Evaluation of five screening tests licensed in Argentina for detection of hepatitis C virus antibodies

This study was conducted to compare among the most recent generation of five screening tests licensed in Argentina, in order to evaluate which of the tests has the best sensitivity for detection of antibodies against hepatitis C virus (HCV). The tests analyzed were: Detect-HCV (3.0) Biochem ImmunoSystems, Canada; Hepatitis C EIA Wiener Lab., Argentina; Equipar HCV Ab, Italy; Murex HCV 4.0, UK and Serodia-HCV particles agglutination test, Japan. The results obtained showed high discrepancy between the different kits used and show that some of the tests assessed have a low sensitivity for anti-HCV detection in both chronic infections and early seroconversion, and indicate that among the commercially available kits in Argentina, Murex HCV 4.0 (UK) and Serodia-HCV particles agglutination test (Japan) have the best sensitivity for HCV screening. Although the sensitivity of the assays is the first parameter to be considered for blood screening, more studies should be carried out to assess the specificity of such assays.

Comparison of qualitative (COBAS AMPLICOR HCV 2.0 versus VERSANT HCV RNA) and quantitative (COBAS AMPLICOR HCV monitor 2.0 versus VERSANT HCV RNA 3.0) assays for hepatitis C virus (HCV) RNA detection and quantification: impact on diagnosis and treatment of HCV infections

Quantitative measurements of serum hepatitis C virus (HCV) RNA are becoming increasingly important in the management of HCV-infected patients. Here we compared two quantitative assays, the COBAS AMPLICOR HCV Monitor 2.0 assay (Roche Diagnostics) and the branched DNA-based VERSANT HCV RNA 3.0 assay (Bayer Diagnostics) for HCV RNA measurement in 344 samples derived from 120 patients with chronic genotype 1 HCV infection. The overall concordance between the results of the two tests was 95%, and the HCV RNA titers within the dynamic ranges of the assays correlated very well (r2=0.86). Furthermore, both tests performed equally well in determining an early viral response at week 1 or 4 during antiviral therapy. We also compared two qualitative HCV RNA detection assays: the COBAS AMPLICOR HCV 2.0 assay versus the transcription-mediated amplification (TMA)-based VERSANT HCV RNA qualitative assay. Stored samples from sustained responders to interferon-ribavirin therapy were retested by the HCV TMA assay and were found to contain no detectable HCV RNA, demonstrating complete concordance between the results of PCR and TMA. However, HCV RNA was detected by the TMA assay in end-of-treatment (ETR) samples from 33% of patients with relapses who were HCV RNA negative according to the COBAS AMPLICOR assay. This observation suggests that a TMA assay can lead to a more correct definition of the ETR response.

Approach to the management of patients with chronic hepatitis C who failed to achieve sustained virologic response

The combination of peginterferon and ribavirin is the most effective therapy for patients with chronic hepatitis C virus (HCV) infection. Although more than half of all patients are able to achieve a sustained virologic response (SVR), a significant proportion of patients, particularly those with genotype 1, fail to have undetectable HCV RNA during treatment or relapse after completing therapy with return of detectable HCV RNA. The management of these patients creates a formidable challenge. This article outlines various strategies for patients who have failed to achieve SVR and discusses the merits of different approaches to management.

Prevention could be less cost-effective than cure: the case of hepatitis C screening policies in France

OBJECTIVES

To access the cost-effectiveness of French recommendations for hepatitis C virus (HCV) screening and the extent to which earlier identification of carriers may or not improve the cost-effectiveness of therapeutic strategies.

METHODS

Cost-effectiveness analysis were performed using decision-tree analysis and a Markov model. Four alternative strategies were compared: no screening and no treatment; initiation of HCV treatment after the diagnosis of cirrhosis; and two alternative strategies refer to the current French policies of HCV testing, i.e., two enzyme immunoblot assay (EIA) tests in series, or a polymerase chain reaction (PCR) analysis after the first positive EIA test. Costs were computed from the viewpoint of the health care system. The analysis has been applied to populations particularly at risk of infection, as well as the general population.

RESULTS

The "wait and treat cirrhosis" strategy was more cost-effective in the general population and in transfusion recipients. The incremental cost-effectiveness ratio of this strategy compared with baseline strategy was 3,476 of euros and Euro15,300 in respective cohorts. Considering the HCV screening strategy, the additional cost would be of Euro4,933 and Euro240,250 per additional year of life saved, respectively. In the intravenous drug user (IDU) population, the "two ElA" screening strategy was the more cost-effective alternative, with an additional cost of Euro3,825 per additional year of life saved.

CONCLUSIONS

HCV screening would be discarded for transfusion recipients but should be encouraged for IDUs and also for the general population, in which the additional cost of screening is an order of magnitude more acceptable.

Comparison of three commercially available assays for HCV RNA using the international unit standard: implications for management of patients with chronic hepatitis C virus infection in clinical practice

OBJECTIVES

The present study was performed to evaluate the impact of the international unit standard for measuring HCV RNA in the management of patients with chronic hepatitis C virus (HCV) infection.

METHODS

The three assays used were Amplicor Monitor PCR, the National Genetics Institute PCR assay, and branched chain DNA. HCV RNA was measured at four time points (baseline, 3 months after the start of therapy, at the end of treatment, and 6 months after discontinuation of therapy) in 106 consecutive patients who received interferon and ribavirin for chronic HCV.

RESULTS

The mean age of the patients was 44 yr. Of the patients, 62% were male, 24% were African American, 38% had bridging fibrosis or cirrhosis, and 75% were HCV genotype 1. Of the 424 samples analyzed, 82-89% of values were within 1 log unit and 85-92% were within 2 log units by the various assays. This variability was not dependent upon HCV genotype. HCV RNA was undetectable in 1.4-6.8% of samples when virus was detected by another assay. The mean HCV RNA in these discordant samples was 1.47-6.33 log IU/ml (30-2,100,000 IU/ml).

CONCLUSIONS

These data demonstrate that approximately 90% of serum values for HCV RNA were within 1 log unit by the international unit standard regardless of which virological assay was used. However, false positive and false negative results as well as variations in the HCV RNA level of more than 1 to 2 log units can occur with any of the assays, and these results may have an impact upon the management of patients receiving interferon therapy. It is therefore unwise in clinical practice to base important treatment decisions upon a single HCV RNA determination.

Current and future hepatitis C virus diagnostic testing: problems and advancements

Serological antibody assays used in hepatitis C virus diagnosis have improved in sensitivity and specificity. However, detection of active viremia or monitoring levels of virus during or after patient treatment is most commonly undertaken using nucleic acid-based technologies. Advancements in diagnostic technologies and implications for managing patients with hepatitis C in various clinical settings are discussed.

An analysis of published trials of interferon monotherapy in children with chronic hepatitis C

BACKGROUND

Although no therapeutic regimen has received Food and Drug Administration approval for treating children with chronic hepatitis C viral infection (CHC), there have been a number of pediatric interferon-alpha (IFN-alpha) trials. The purpose of this study was to perform a critical review of these trials to determine 1) end-of-treatment (ETR) and sustained-response (SR) rates, 2) predictors of response to therapy, and 3) safety of and tolerance to IFN-alpha in children with CHC.

METHODS

Relevant studies in the English-language medical literature and abstracts (January 1990 through November 2000) were identified by searching for manuscripts that contained the key words "children," "hepatitis C," and "interferon." Trials were considered eligible for inclusion in this analysis if criteria for treatment included positive serum polymerase chain reaction for hepatitis C virus RNA (HCV PCR).

RESULTS

Twenty published manuscripts of the use of IFN-alpha in children with CHC were found, of which 12 met our inclusion criteria. Twenty-two abstracts, of which seven met our inclusion criteria, were identified. In the 19 included trials, 366 treated and 105 untreated children were observed; five countries were represented. Average ETR was 54% (0%-91%) and average SR was 36% (0%-73%). The SR in children with genotype 1 was 27% versus 70% for nongenotype 1 ( P = 0.001). Five of 105 (5%) untreated controls exhibited spontaneous viral clearance.

CONCLUSIONS

To date, there is no published large-scale, multicenter, prospective, placebo-controlled randomized trial of the use of IFN-alpha in children with CHC. The data in this review suggest that IFN-alpha in children with CHC does have reasonable efficacy and safety. This review highlights the need for a more systematic design of future pediatric CHC trials. Ideally, such trials would be large scale, prospective, and controlled, and would include HCV genotype and viral load, histology, quality of life measures, and systematic recording of adverse events and of effects of therapy on growth and development.

[Immunoblot as a supplemental test to detect antibodies to hepatitis C virus in blood donors]

Supplemental tests using Immunoblot are recommended to improve specificity of anti-HCV by ELISA. In Brazil immunoblot is not officially recommended. Aiming to identify EIA false-positive rate 70 positive EIA anti-HCV blood donors were submitted to 3rd generation immunoblot at Hemocentro of Mato Grosso State where polymerase chain reaction tests are not performed. There were 44 (62.9%) immunoblot-positive, 22 (31.4%) negative and 4 (5.7%) indeterminate. Anti-HCV immunoblot can distinguish blood donors with false-positive ELISA from those who need medical assessment. Our data suggest that immunoblot could be useful in Brazilian blood banks where molecular biology tests are not available.

Hepatitis C: a brief clinical overview

Hepatitis C has emerged as an important public health problem that has affected 3.9 million Americans and 170 million people worldwide and is currently the most common indication for orthotopic liver transplantation. The disease, characterized by asymptomatic onset, is often discovered incidentally through blood tests obtained during routine physical examination or before blood donation. Spontaneous recovery occurs in about 20% of patients. Among those who remain chronically infected, an equal percentage progress to cirrhosis within 20 yr, have stable nonprogressive disease, or progress more slowly over 40 to 60 yr. At present, combination therapy with interferon plus ribavirin is the treatment of choice for hepatitis C-infected patients identified as appropriate candidates for therapy. Unfortunately, sustained response rates are only modest, with a lesser response among African Americans, and treatment is associated with a number of side effects. Research studies attempting to improve the response to current therapy, to identify alternative treatments or treatment strategies, and to develop an effective vaccine are ongoing and will hopefully provide us with the ability to better understand and manage hepatitis C.