Improved version 2.0 qualitative and quantitative AMPLICOR reverse transcription-PCR tests for hepatitis C virus RNA: calibration to international units, enhanced genotype reactivity, and performance characteristics

Perspectives on systematic optimization of ultrasensitive biosensors through experimental design

Biosensors have demonstrated versatility across numerous applications; however, their systematic optimization remains a primary obstacle, limiting their widespread adoption as dependable point-of-care tests. Experimental design, a powerful chemometric tool, offers a solution by effectively guiding the development and optimization of ultrasensitive biosensors. This perspective review provides an overview of recent applications of experimental design in the deployment of optical and electrical ultrasensitive biosensors. Various experimental designs, including full factorial, central composite, and mixture designs, are examined as systematic methodologies for optimizing biosensor fabrication, accounting for both individual variable effects and their interactions. Illustrative examples showcasing the optimization of optical and electronic biosensors through design of experiments are presented and critically analyzed. Finally, the future prospects of experimental design in the biosensor community are outlined, highlighting its potential to expedite development and bolster the performance of biosensing devices for point-of-care diagnostics, thereby facilitating their sustainable and reliable integration.

Rapid detection of hepatitis C virus using recombinase polymerase amplification

Over 71 million people are infected with hepatitis C virus (HCV) worldwide, and approximately 400,000 global deaths result from complications of untreated chronic HCV. Pan-genomic direct-acting antivirals (DAAs) have recently become widely available and feature high cure rates in less than 12 weeks of treatment. The rollout of DAAs is reliant on diagnostic tests for HCV RNA to identify eligible patients with viremic HCV infections. Current PCR-based HCV RNA assays are restricted to well-resourced central laboratories, and there remains a prevailing clinical need for expanded access to decentralized HCV RNA testing to provide rapid chronic HCV diagnosis and linkage to DAAs in outpatient clinics. This paper reports a rapid, highly accurate, and minimally instrumented assay for HCV RNA detection using reverse transcription recombinase polymerase amplification (RT-RPA). The assay detects all HCV genotypes with a limit of detection of 25 copies per reaction for genotype 1, the most prevalent in the United States and worldwide. The clinical sensitivity and specificity of the RT-RPA assay were both 100% when evaluated using 78 diverse clinical serum specimens. The accuracy, short runtime, and low heating demands of RT-RPA may enable implementation in a point-of-care HCV test to expand global access to effective treatment via rapid chronic HCV diagnosis.

Red complex periodontal pathogens are risk factors for liver cirrhosis

Periodontal disease has been associated with liver disease; however, the identities of the periodontal disease-causing bacteria in patients with viral liver disease remain unknown. The aim of the present study was to determine the counts of the 3 periodontal pathogens that form the red complex in chronic periodontitis (Porphyromonas gingivalis, Tannerella forsythia and Treponema denticola) and 3 other bacteria (Aggregatibacter actinomycetemcomitans, Prevotella intermedia and Fusobacterium necrophorum) in patients with liver disease. A total of 47 patients with liver disease were divided into two groups based on the counts of the red complex bacteria: group A (high counts of red complex bacteria) and group B (low counts of red complex bacteria). The counts of the 6 types of bacteria in saliva and the prevalence of P. gingivalis-specific fimA genotype were determined. In addition, salivary occult blood tests and serological assays were performed. Univariate and multivariate logistic regression analyses were used to analyze the risk factors between the two groups of patients. Hepatitis C virus-related liver disease was the most frequent (41/47; 87.2%) occurrence followed by liver cirrhosis (LC; 12/47; 25.5%) and oral lichen planus (32/47; 68.1%). The significant risk factors between the two groups were LC, albumin (Alb) level, ratios of each bacteria and prevalence of the fimA II genotype. The 3 factors identified in the multivariate analysis to be associated with the red complex bacteria count were low Alb level (<3.7 g/dl), LC and fimA II genotype, with adjusted odds ratios of 6.93, 4.72 and 4.08, respectively (P<0.05). These data indicated that patients with LC were at increased risk of presenting with the red complex bacteria leading to periodontal disease progression. Therefore, these patients may need to take additional care of their oral health compared with patients without LC, which may prove beneficial for the maintenance of their general health.

HCV Detection, Discrimination, and Genotyping Technologies

According to the World Health Organization (WHO), 71 million people were living with Hepatitis C virus (HCV) infection worldwide in 2015. Each year, about 399,000 HCV-infected people succumb to cirrhosis, hepatocellular carcinoma, and liver failure. Therefore, screening of HCV infection with simple, rapid, but highly sensitive and specific methods can help to curb the global burden on HCV healthcare. Apart from the determination of viral load/viral clearance, the identification of specific HCV genotype is also critical for successful treatment of hepatitis C. This critical review focuses on the technologies used for the detection, discrimination, and genotyping of HCV in clinical samples. This article also focuses on advantages and disadvantages of the reported methods used for HCV detection, quantification, and genotyping.

The future of viral hepatitis testing: innovations in testing technologies and approaches

A large burden of undiagnosed hepatitis virus cases remains globally. Despite the 257 million people living with chronic hepatitis B virus infection, and 71 million with chronic viraemic HCV infection, most people with hepatitis remain unaware of their infection. Advances in rapid detection technology have created new opportunities for enhancing access to testing and care, as well as monitoring of treatment. This article examines a range of other technological innovations that can be leveraged to provide more affordable and simplified approaches to testing for HBV and HCV infection and monitoring of treatment response. These include improved access to testing through alternative sampling methods (use of dried blood spots, oral fluids, self-testing) and combination rapid diagnostic tests for detection of HIV, HBV and HCV infection; more affordable options for confirmation of virological infection (HBV DNA and HCV RNA) such as point-of-care molecular assays, HCV core antigen and multi-disease polyvalent molecular platforms that make use of existing centralised laboratory based or decentralised TB and HIV instrumentation for viral hepatitis testing; and finally health system improvements such as integration of laboratory services for procurement and sample transportation and enhanced data connectivity to support quality assurance and supply chain management.

Who to test and how to test for chronic hepatitis C infection - 2016 WHO testing guidance for low- and middle-income countries

Testing and diagnosis of hepatitis C virus (HCV) infection is the gateway for access to both treatment and prevention services, and crucial for an effective hepatitis epidemic response. In contrast to HIV, a systematic approach to hepatitis C testing has been fragmented and limited to a few countries, and there remains a large burden of undiagnosed cases globally. Key challenges in the current hepatitis testing response, include lack of simple, reliable, and low cost diagnostic tests, laboratory capacity, and testing facilities; inadequate data to guide country-specific hepatitis testing approaches and who to test; stigmatization and social marginalization of some groups with or at risk of viral hepatitis; and lack of international or national guidelines on hepatitis testing for resource-limited settings. New tools to support the hepatitis global response include the 2016 Global Hepatitis Health Sector Strategy which include targets for testing and diagnosis, and World Health Organization (WHO) 2016 hepatitis testing guidelines for adults, adolescents, and children in low- and middle-income countries. The testing guidance complements recent published WHO guidance on the prevention, care and treatment of chronic hepatitis C and hepatitis B infection. These testing guidelines outline the public health approach to strengthening and expanding current testing practices for HCV and HBV and address what serological and virological assays to use, and who to test, as well as interventions to promote linkage to prevention and care after testing. They are intended for use across all age groups and populations. See boxes for key recommendations. Future directions and innovations in viral hepatitis testing include use of point-of-care assays for nucleic acid testing (NAT) and core antigen; validation of dried blood spots specimens with different commercial serological and NAT assays; multiplex and polyvalent platforms for integrated testing of HIV, HBV and HCV; and potential for self-testing.

Successful Treatment of Hepatitis C Virus-associated Oral Lichen Planus by Interferon-free Therapy with Direct-acting Antivirals

OBJECTIVES

Oral lichen planus (OLP) is one of the extrahepatic manifestations of hepatitis C virus (HCV) infection. Presently developed interferon (IFN)-free direct-acting antivirals (DAAs) used to treat HCV infection have low side effect profiles and high efficacy. However, there are no studies examining the relationship between OLP and IFN-free DAAs. The aim of this study was to evaluate the disease course in patients with HCV-associated OLP, who received treatment with IFN-free DAAs.

METHODS

Seven patients with HCV-related OLP (including one with cutaneous LP), who received IFN-free treatment with daclatasvir (DCV)/asunaprevir (ASV) at our hospital in Japan from October, 2014 to February, 2015 were enrolled in the study. The subjects included four males and three females (average age, 73.9 years). We compared the symptoms of OLP in the patients before and at 24 weeks after the end of DAA therapy.

RESULTS

No worsening of symptoms was observed during treatment with the DAAs. The symptoms of OLP had subsided in all seven patients. Lesions of OLP and cutaneous LP disappeared in four, and improved in three of the seven patients after sustained virological response 24. No systemic clinical adverse events were observed in all patients.

CONCLUSIONS

Herein, we have reported the outcomes of HCV-associated OLP in patients who received successful treatment with IFN-free DAAs, using the DCV/ASV combination therapy.

Diagnosis and Management of Hepatitis C Virus Infection

The hepatitis C virus (HCV) infects more than 200 million people globally, with increasing incidence, especially in developing countries. HCV infection frequently progresses to chronic liver disease, creating a heavy economic burden on resource-poor countries and lowering patient quality of life. Effective HCV diagnosis, treatment selection, and treatment monitoring are important in stopping disease progression. Serological assays, which detect anti-HCV antibodies in the patient after seroconversion, are used for initial HCV diagnosis. Qualitative and quantitative molecular assays are used to confirm initial diagnosis, determine viral load, and genotype the dominant strain. Viral load and genotype information are used to guide appropriate treatment. Various other biomarker assays are performed to assess liver function and enable disease staging. Most of these diagnostic methods are mature and routinely used in high-resource countries with well-developed laboratory infrastructure. Few technologies, however, are available that address the needs of low-resource areas with high HCV prevalence, such as Africa and Southeast Asia.

Association of Periodontal Diseases and Liver Fibrosis in Patients With HCV and/or HBV infection

BACKGROUND

Periodontal disease and systemic health are closely associated. However, there is no data supporting the association between periodontal disease and patients with liver diseases associated with hepatitis C virus (HCV) and/or hepatitis B virus (HBV) infection.

OBJECTIVES

The aim of this study was to evaluate the association between periodontitis and progression of liver diseases in patients with HCV and/or HBV infection.

PATIENTS AND METHODS

In this retrospective study, 351 patients with HCV- and/or HBV-related liver diseases underwent screening for periodontal disease using the Salivaster® salivary occult blood test from February 2010 to June 2014. Furthermore, we examined the prevalence of fimbrillin (fimA) genotype of Porphyromonas gingivalis (P. gingivalis) in 28 HCV-infected patients visited at our hospital between January 2013 and June 2014. P. gingivalis with fimA genotype with types I to V was further detected using a PCR method.

RESULTS

Of 351 patients, 76 patients (group 1) had a strong positive result for salivary occult blood test and 275 patients (group 2) had weak positive or negative test results. Significant factors between the groups were obesity, level of AST, ALT, LDH, ALP, Alb, D.Bil, T.cho, AFP, platelets (Plt), IRI, HOMA-IR, current interferon (IFN) treatment and the daily frequency of tooth brushing. Between-groups analysis indicated that total protein (T.pro) level and liver fibrosis were significant factors. According to multivariate analysis, five factors were associated with periodontal disease as Plt count below 80000, brushing teeth only once a day, current IFN treatment, aged 65 years or older and obesity. The adjusted odds ratios for these five factors were 5.80, 3.46, 2.87, 2.50 and 2.33, respectively, and each was statistically significant. Twenty-eight saliva specimens had positive results for P. gingivalis with fimA genotype types I to V. The prevalence of fimA genotype II was higher in 14 patients with liver cirrhosis or a history of hepatocellular carcinoma treatment (group B, 50.00%) than 14 patients with only hepatitis C (group A, 21.43%).

CONCLUSIONS

Periodontitis might be associated with progression of viral liver disease; hence, controlling oral disease is essential for the prevention and management of liver fibrosis.

The importance of HCV RNA measurement for tailoring treatment duration

The introduction of telaprevir and boceprevir in the treatment of chronically HCV genotype 1 infected patients has led to substantially improved sustained virologic response rates and shorter treatment duration for a growing group of patients. Management and monitoring of patients receiving protease inhibitor-based triple therapy is of major importance and has become more complicated. Close monitoring of HCV RNA levels for patients on protease inhibitor-based therapy to identify subjects who are eligible for shortening of treatment duration, are virological non-responders or are in danger of experiencing a viral breakthrough is strongly recommended. Several virological tools including qualitative and quantitative HCV RNA assays for detection and quantification of HCV RNA are commercially available. We review these methods and their implications for HCV therapy as well as current sustained virologic response definition, stopping rules and recommendations for protease inhibitor-based treatment durations.

Is HCV core antigen a reliable marker of viral load? An evaluation of HCV core antigen automated immunoassay

BACKGROUND

Hepatitis C viral (HCV) load detection and quantification is routinely accomplished by HCV RNA measurement, an expensive but essential test, both for the diagnosis and treatment of chronic hepatitis C (CHC). HCV core antigen (Ag) testing has been suggested as an attractive alternative to molecular diagnostics. The aim of the study was to evaluate an automated chemiluminescent immunoassay (CLIA) for HCV core Ag measurement in comparison to quantitative HCV RNA determination.

METHODS

HCV Ag was measured in 105 anti-HCV positive patients, from which 89 were HCV RNA positive with CHC and 16 HCV RNA negative after spontaneous HCV clearance. Viral load was quantified with branched DNA (bDNA, Versant, Siemens). Sera were stored at -70°C and then tested with the Architect HCV Ag test (Abbott Laboratories), a two-step CLIA assay, with high throughput and minimal handling of the specimens. Statistical analysis was performed on logarithmically transformed values.

RESULTS

HCV-Ag was detectable and quantifiable in 83/89 and in grey zone in 4/89 HCV RNA positive sera. HCV-Ag was undetectable in all 16 HCV RNA negative samples. The sample with the lowest viral load that tested positive for HCV-Ag contained 1200 IU/mL HCV RNA. There was a positive correlation between HCV RNA and HCV-Ag (r=0.89). The HCV RNA/ HCV Ag ratio varied from 1.5 to 3.25.

CONCLUSION

The HCV core Ag is an easy test with comparable sensitivity (>90%) and satisfactory correlation with the HCV RNA bDNA assay. Its role in diagnostics and other clinical applications has to be determined based on cost effectiveness.

Effect of branched-chain amino acid-enriched nutritional supplementation on interferon therapy in Japanese patients with chronic hepatitis C virus infection: a retrospective study

Background

The aims of this study were to evaluate the effects of nutritional supplementation with branched-chain amino acids (BCAA) with zinc component (Aminofeel®) on adherence to and outcome of therapy in patients treated with interferon (IFN) for chronic hepatitis C and cirrhosis and to determine whether to recommend the supplement.

Methods

In this retrospective study, 51 patients who received IFN therapy were investigated among 203 consecutive patients who visited our hospital and were advised regarding the potential benefit of taking Aminofeel®. Each patient was free to choose whether to purchase and take Aminofeel®.

Results

Twenty four patients (group 1-A) took Aminofeel® during standard IFN therapy and 13 (group 1-B) did not. Low-dose, long-term IFN (maintenance) therapy, mainly peglated (Peg)-IFN alpha 2a, was administered to 14 patients who were difficult to treat, because of no effect or harmful side effects with standard IFN therapy, and who had advanced liver fibrosis. Among the 14, 11 patients (group 2-A) took Aminofeel® and 3 (group 2-B) did not. The prevalence of obesity was significantly higher (P=0.04) in group 1-A than in group 1-B. The rate of adherence to IFN therapy was higher in group 1-A (83.3%) than in group 1-B (53.8%, P=0.05). There were no significant differences between the two groups in the rates of sustained virological response (SVR) to IFN therapy. According to multivariate analysis, two factors, SVR and intake of Aminofeel®, were associated with successful adherence to IFN therapy. The adjusted odds ratios for these two factors were 13.25 and 12.59, respectively, and each was statistically significant. The SVR rate of maintenance IFN therapy was in 18.2% group 2-A and 0% in group 2-B.

Conclusion

Our data show that BCAA intake is useful for adherence to and effect of IFN therapy for patients with chronic hepatitis C. Nutritional supplementation with BCAA seems to be useful for HCV-infected patients receiving IFN therapy because it is impossible to introduce standard treatment for all patients among Japan's aging population.

Candidiasis and other oral mucosal lesions during and after interferon therapy for HCV-related chronic liver diseases

Background

Oral lichen planus (OLP) is seen frequently in patients with hepatitis C virus (HCV) infection. The aim of this study was to evaluate the occurrence of oral candidiasis, other mucosal lesions, and xerostomia during interferon (IFN) therapy for HCV infection.

Methods

Of 124 patients with HCV-infected liver diseases treated with IFN therapy in our hospital, 14 (mean age 56.00 ± 12.94 years) who attended to receive administration of IFN once a week were identified and examined for Candida infection and other oral lesions and for the measurement of salivary flow. Serological assays also were carried out.

Results

Cultures of Candida from the tongue surfaces were positive in 7 (50.0%) of the 14 patients with HCV infection at least once during IFN therapy. C. albicans was the most common species isolated. The incidence of Candida during treatment with IFN did not increase above that before treatment. Additional oral mucosal lesions were observed in 50.0% (7/14) of patients: OLP in three (21.4%), angular cheilitis in three (21.4%) and recurrent aphthous stomatitis in one (7.1%). OLP occurred in one patient before treatment with IFN, in one during treatment and in one at the end of treatment. 85.7% of the oral lesions were treated with topical steroids. We compared the characteristics of the 7 patients in whom Candida was detected at least once during IFN therapy (group 1) and the 7 patients in whom Candida was not detected during IFN therapy (group 2). The prevalence of oral mucosal lesions (P=0.0075) and incidence of external use of steroids (P=0.0308) in group 1 were significantly higher than in group 2. The average body weight of group 1 decreased significantly compared to group 2 (P=0.0088). Salivary flow decreased in all subjects throughout the course of IFN treatment and returned at 6^th months after the end of treatment. In group 1, the level of albumin at the beginning of the 6^th month of IFN administration was lower than in group 2 (P=0.0550). According to multivariate analysis, one factor, the presence of oral mucosal lesions, was associated with the detection of Candida. The adjusted odds ratio for the factor was 36.00 (95% confidence interval 2.68-1485.94).

Conclusion

We should pay more attention to oral candidiasis as well as other oral mucosal lesions, in patients with weight loss during IFN treatment.

A retrospective case-control study of hepatitis C virus infection and oral lichen planus in Japan: association study with mutations in the core and NS5A region of hepatitis C virus

Background

The aims of this study were to assess the prevalence of hepatitis C virus (HCV) infection in Japanese patients with oral lichen planus and identify the impact of amino acid (aa) substitutions in the HCV core region and IFN-sensitivity-determining region (ISDR) of nonstructural protein 5A (NS5A) associated with lichen planus.

Methods

In this retrospective study, 59 patients (group 1-A) with oral lichen planus among 226 consecutive patients who visited our hospital and 85 individuals (group 1-B, controls) with normal oral mucosa were investigated for the presence of liver disease and HCV infection. Risk factors for the presence of oral lichen planus were assessed by logistic regression analysis. We compared aa substitutions in the HCV core region (70 and/or 91) and ISDR of NS5A of 12 patients with oral lichen planus (group 2-A) and 7 patients who did not have oral lichen planus (group 2-B) among patients (high viral loads, genotype 1b) who received interferon (IFN) therapy in group1-A.

Results

The prevalence of anti-HCV and HCV RNA was 67.80% (40/59) and 59.32% (35/59), respectively, in group 1-A and 31.76% (27/85) and 16.47% (14/85), respectively, in group 1-B. The prevalence of anti-HCV (P < 0.0001) and HCV RNA (P < 0.0001) in group 1-A was significantly higher than those in group 1-B. According to multivariate analysis, three factors - positivity for HCV RNA, low albumin level (< 4.0 g/dL), and history of smoking - were associated with the development of oral lichen planus. The adjusted odds ratios for these three factors were 6.58, 3.53 and 2.58, respectively, and each was statistically significant. No significant differences in viral factors, such as aa substitutions in the core region and ISDR of NS5A, were detected between the two groups (groups 2-A and -B).

Conclusion

We observed a high prevalence of HCV infection in patients with oral lichen planus. Longstanding HCV infection, hypoalbuminemia, and smoking were significant risk factors for the presence of oral lichen planus in patients. It is advisable for Japanese patients with lichen planus to be tested for HCV infection during medical examination.

Performance of the novel Qiagen artus QS-RGQ viral load assays compared to that of the Abbott RealTime system with genetically diversified HIV and hepatitis C Virus plasma specimens

We compared two novel Qiagen QS-RGQ viral load assays with the established Abbott RealTime assays on a highly diversified panel of 121 human immunodeficiency virus (HIV) and 107 hepatitis C virus (HCV) specimens. The quantifications correlated well for all HIV and HCV types, but Qiagen yielded higher HCV concentrations than Abbott, predominantly in genotypes 4 and 5.

High prevalence of hepatitis C virus infection in Airin district, Osaka, Japan: A hospital-based study of 1162 patients

AIM

  The Airin district, located in Nishinari-ku, Osaka, is known as Japan's largest slum area, and has the largest concentration of day laborers in the country. We conducted a large hospital-based study to determine the prevalence of hepatitis C virus (HCV) infection in the district.

METHODS

  The subjects were 1162 men (mean age, 57 ± 9 years) admitted to the Osaka Socio-Medical Center Hospital between April 2005 and March 2008. Their case records were retrospectively reviewed.

RESULTS

  Anti-HCV antibodies were found in 218 (18.8%) patients; in contrast, only 24 (2.1%) patients had hepatitis B surface antigen. The prevalence of anti-HCV antibodies was 59% among the 122 patients admitted for liver diseases and 14% among the 1040 patients with other diseases. Among 927 patients with normal alanine aminotransferase levels (≤40 IU/L), 128 (13.8%) had anti-HCV antibodies. The prevalence of anti-HCV antibodies increased with age significantly (P < 0.001). At least 33 of the 218 (15%) patients with anti-HCV antibodies admitted to having a history of injection drug use. Interferon therapy was initiated in 26 patients (11 with genotype 1, 14 with genotype 2 and one unclassifiable), but only six completed their scheduled regimens. Hepatocellular carcinoma was diagnosed in 20 patients, but only seven had early-stage disease in which curative treatment, such as surgical hepatectomy or percutaneous ablation, was indicated.

CONCLUSION

  The prevalence of HCV infection in the Airin district is extremely higher than that in the Japanese general population. Patient education and strict action against illegal drug use are indispensable to prevent the spread of HCV infection from the district.

Ultrasensitive and selective electrochemical identification of hepatitis C virus genotype 1b based on specific endonuclease combined with gold nanoparticles signal amplification

This work proposes a new strategy for the electrochemical detection of hepatitis C virus (HCV) RNA level and identification of HCV-1b genotype based on the site-specific cleavage of BamHI endonuclease combined with gold nanoparticles (AuNPs) signal amplification. The assay procedures include the reverse transcription, polymerase chain reaction (PCR) amplification, and electrochemical detection. The samples of 244 mer sequence of HCV RNA from the highly conserved region of HCV-1a, HCV-1b, HCV-1, and HCV-6a, respectively, were first reverse transcribed into complementary cDNA and amplified by PCR. The PCR-amplified samples were then analyzed using a synthetic 21 mer DNA probe, which has been assembled on the electrode surface via a bifunctional molecule of p-aminobenzoic acid (ABA). The results demonstrated that the developed approach can be used for specifically identification of the HCV-1b genotype and selective and sensitive detection of HCV-1b cDNA (244 mer) with a detection limit as low as (3.1 ± 0.8) × 10(-22) M (less than 200 molecules; the concentration refers to the one before PCR amplification). Moreover, the developed method has an ability to discriminate the HCV-1b cDNA sequence from even single-base mismatched DNA sequence, to assay the HCV-1b cDNA level precisely from the mixture of HCV-1, HCV-1b, HCV-1a, and HCV-6a, and to detect HCV in real clinical samples. The protocol has high potential application in molecular diagnostics of HCV in clinical environments.

Performance of the COBAS® AmpliPrep/COBAS TaqMan® automated system for hepatitis C virus (HCV) quantification in a multi-center comparison

BACKGROUND

Quantitative HCV RNA testing is considered standard of care for monitoring during treatment of patients infected with HCV. The COBAS(®) AmpliPrep/COBAS(®) TaqMan(®) HCV Test fully automates specimen processing and reaction assembly for HCV viral load testing using reverse transcription and real-time PCR amplification.

OBJECTIVES

The performance of the COBAS(®) AmpliPrep/COBAS(®) TaqMan(®) HCV Test was evaluated in a multi-center study.

STUDY DESIGN

Typical plasma based specimens were tested for accuracy, analytic range of measurement, reproducibility and genotype specific quantitation.

RESULTS

Linear regression analysis of the quantitative results demonstrated a linear range of detection from 50 to 5 million (1.7-6.7 log(10))IU/mL and a coefficient of determination (R(2)) of 0.9948. The precision of the assay was highly reproducible within and between runs and among laboratories with coefficients of variance (CV) ranging from 6.7% to 40.0% across the seven laboratories. A representative sample for each of the six major HCV genotypes demonstrated reproducible quantitation between the seven laboratories.

CONCLUSIONS

The COBAS(®) AmpliPrep/COBAS(®) TaqMan(®) HCV Test is a reliable and sensitive assay for HCV RNA quantitation.

Dental problems delaying the initiation of interferon therapy for HCV-infected patients

BACKGROUND

There has been little discussion about the importance of oral management and interferon (IFN) therapy, although management of the side effects of therapy for chronic hepatitis C has been documented. This study determined whether dental problems delayed the initiation of IFN therapy for hepatitis C virus (HCV)-infected patients.

RESULTS

We analyzed 570 HCV-infected patients who were admitted to our hospital from December 2003 to June 2010 for treatment consisting of pegylated IFN (Peg-IFN) monotherapy or Peg-IFN/ribavirin combination therapy. The group comprised 274 men and 296 women with a mean age 57.2 years. Of the 570 patients, six could not commence Peg-IFN therapy, despite their admission, because of dental problems such as periodontitis, pupitis, and pericoronitis. The ages of six whose dental problems delayed the initiation of Peg-IFN ranged from 25 to 67 years, with a mean age of 47.3 +/- 15.2 years. IFN therapy was deferred for 61.3 +/- 47.7 days. Among the six subjects for whom IFN treatment was delayed, only one had a salivary flow that was lower than the normal value.

CONCLUSIONS

Treatment of dental infections is required before IFN therapy for HCV infection can be started. To increase the depth of understanding of oral health care, it is hoped that dentists and medical specialists in all areas will hold discussions to generate cooperation.

Definition of rapid virologic response with a highly sensitive real-time PCR-based HCV RNA assay in peginterferon alfa-2a plus ribavirin response-guided therapy

BACKGROUND & AIMS

Assessing hepatitis C virus (HCV)-RNA levels is integral to response-guided therapy. Rules for early discontinuation and determination of treatment duration were mainly established with HCV-RNA assays with a detection limit of 50IU/ml (COBAS Amplicor HCV [CA]). The currently used real-time PCR-based COBAS Ampliprep/COBAS-TaqMan HCV (CAP-CTM) test has a detection limit of approximately 10IU/ml. It is unknown whether shortening of treatment duration to 16/24 weeks in patients with rapid virological response at week 4 (RVR) and viral loads between 10 and 50IU/ml is possible.

METHODS

We reanalysed stored serum from two large, multinational, randomized trials in which patients were treated with peginterferon alfa-2a/ribavirin (n=962). Results of CAP-CTM with truly undetectable HCV RNA and those <15IU/ml, which includes patients with residual viraemia (<15), were compared with the originally obtained results using the CA assay.

RESULTS

RVR rates were comparable for CA (<50) and CAP-CTM (<15) with 32% and 32% for genotype (gt) 1 and 50% and 49% for gt2/3 patients, respectively. A significantly smaller number of samples really had truly undetectable HCV RNA by the CAP-CTM assay (24% for gt1, 37% for gt2/3). However, sustained virological response rates after shortened treatment (16/24weeks) were not significantly different in patients with a RVR <50, a RVR <15 and RVR undetectable (82%, 83%, 83% for 24weeks gt1 and 95%, 95%, 94% for 16weeks gt2/3).

CONCLUSIONS

Shortening the treatment duration to 16/24weeks can be performed on the basis of a RVR with HCV-RNA concentrations <15IU/ml by the CAP-CTM assay.

A comprehensive hepatitis C viral kinetic model explaining cure

We propose a model that characterizes and links the complexity and diversity of clinically observed hepatitis C viral kinetics to sustained virologic response (SVR)-the primary clinical end point of hepatitis C treatment, defined as an undetectable viral load at 24 weeks after completion of treatment)-in patients with chronic hepatitis C (CHC) who have received treatment with peginterferon alpha-2a +/- ribavirin. The new attributes of our hepatitis C viral kinetic model are (i) the implementation of a cure/viral eradication boundary, (ii) employment of all hepatitis C virus (HCV) RNA measurements, including those below the lower limit of quantification (LLOQ), and (iii) implementation of a population modeling approach. The model demonstrated excellent positive (99.3%) and negative (97.1%) predictive values for SVR as well as high sensitivity (96.6%) and specificity (99.4%). The proposed viral kinetic model provides a framework for mechanistic exploration of treatment outcome and permits evaluation of alternative CHC treatment options with the ultimate aim of developing and testing hypotheses for personalizing treatments in this disease.

Excellent superiority and specificity of COBAS TaqMan HCV assay in an early viral kinetic change during pegylated interferon alpha-2b plus ribavirin treatment

BACKGROUND

An early virological response (EVR) after the start of interferon (IFN) treatment for chronic hepatitis C leads to a successful virological outcome. To analyze an association between sustained virological response (SVR) and EVR by comparing TaqMan with Amplicor assays in HCV genotype 1-infected patients treated with pegylated (PEG)-IFN alpha-2b plus ribavirin (RBV).

METHODS

We retrospectively analyzed a total of 80 HCV genotype 1 patients (39 SVR and 41 non-SVR patients), who received an enough dosage and a complete 48-week treatment of PEG-IFN alpha-2b plus RBV. Serum HCV RNA levels were measured by both TaqMan and Amplicor assays for each patients at Weeks 2, 4, 8 and 12 after the start of the antiviral treatment.

RESULTS

Of the 80 patients with undetectable HCV RNA by Amplicor, 17 (21.3%) patients were positive for HCV RNA by TaqMan at Weeks 12. The quantification results showed that no significant difference in the decline of HCV RNA level between TaqMan and Amplicor 10-fold method assays within the initial 12 weeks of the treatment was found. However, the qualitative analysis showed significant differences of the positive predictive rates for SVR were found between TaqMan (100% at weeks 4 and 100% at weeks 8) and Amplicor (80.0% and 69.6%, respectively).

CONCLUSIONS

The COBAS TaqMan HCV assay is very useful for monitoring HCV viremia during antiviral treatment to predict a SVR in HCV genotype 1 patients.

Hepatitis C virus infection in the family setting of patients with occult hepatitis C

Family members of patients with chronic hepatitis C virus (HCV) infection are at increased risk of HCV infection but the prevalence of HCV among family members of patients with occult HCV infection is not known. Anti-HCV, serum HCV RNA and levels of liver enzymes were determined in 102 family members of 50 index patients with occult HCV infection and in 118 family members of 59 chronic hepatitis C index patients. HCV RNA and/or anti-HCV were detected in 10/102 (9.8%) relatives of patients with occult HCV infection and in 4/118 (3.4%) of patients with chronic hepatitis C. Fourteen additional family members (seven were relatives of index patients with occult HCV infection) had abnormal values of liver enzymes without serological markers of HCV infection. Two of these patients (who were relatives of two index patients with occult HCV infection) underwent a liver biopsy and were diagnosed with an occult HCV infection because HCV RNA was detected in the liver cells in the absence of serological HCV markers. In conclusion, the prevalence of HCV infection among family members of patients with occult HCV infection was similar to that found among family members of patients with chronic hepatitis C. This stresses the need to adopt strategies to prevent the transmission of HCV in the family setting of patients with occult HCV infection.

Prion protein expression and processing in human mononuclear cells: the impact of the codon 129 prion gene polymorphism

Background

So far, all clinical cases of new variant Creutzfeldt-Jakob disease (vCJD), thought to result from the Bovine Spongiform Encephalopathy (BSE) prion agent, have shown Methionine–Methionine (M/M) homozygosity at the M129V polymorphism of the PRNP gene. Although established, this relationship is still not understood. In both vCJD and experimental BSE models prion agents do reach the bloodstream, raising concerns regarding disease transmission through blood transfusion.

Methodology/Principal Findings

We investigated the impact of the M129V polymorphism on the expression and processing of the prion protein in human peripheral blood mononuclear cells (PBMCs) from three blood donor populations with Methionine-Methionine (M/M), Valine-Valine (V/V) and M/V genotypes. Using real-time PCR, ELISA and immunoblot assays we were unable to find differences in prion protein expression and processing relating to the M129V polymorphism.

Conclusions/Significance

These results suggest that in PBMCs, the M129V PrP polymorphism has no significant impact on PrP expression, processing and the apparent glycoform distribution. Prion propagation should be investigated further in other cell types or tissues.

Diagnosing norovirus-associated infectious intestinal disease using viral load

Background

Reverse transcription-polymerase chain reaction (RT-PCR) is the main method for laboratory diagnosis of norovirus-associated infectious intestinal disease (IID). However, up to 16% of healthy individuals in the community, with no recent history of IID, may be RT-PCR positive; so it is unclear whether norovirus is actually the cause of illness in an IID case when they are RT-PCR positive. It is important to identify the pathogen causing illness in sporadic IID cases, for clinical management and for community based incidence studies. The aim of this study was to investigate how faecal viral load can be used to determine when norovirus is the most likely cause of illness in an IID case.

Methods

Real-time RT-PCR was used to determine the viral load in faecal specimens collected from 589 IID cases and 159 healthy controls, who were infected with genogroup II noroviruses. Cycle threshold (Ct) values from the real-time RT-PCR were used as a proxy measure of viral load. Receiver-operating characteristic (ROC) analysis was used to identify a cut-off in viral load for attributing illness to norovirus in IID cases.

Results

One hundred and sixty-nine IID cases and 159 controls met the inclusion criteria for the ROC analysis. The optimal Ct value cut-off for attributing IID to norovirus was 31. The same cut-off was selected when using healthy controls, or IID cases who were positive by culture for bacterial pathogens, as the reference negative group. This alternative reference negative group can be identified amongst specimens routinely received in clinical virology laboratories.

Conclusion

We demonstrated that ROC analysis can be used to select a cut-off for a norovirus real time RT-PCR assay, to aid clinical interpretation and diagnose when norovirus is the cause of IID. Specimens routinely received for diagnosis in clinical virology laboratories can be used to select an appropriate cut-off. Individual laboratories can use this method to define in-house cut-offs for their assays, to provide the best possible diagnostic service to clinicians and public health workers. Other clinical and epidemiological information should also be considered for patients with Ct values close to the cut-off, for the most accurate diagnosis of IID aetiology.

The longitudinal quantitative assessment by transient elastography of chronic hepatitis C patients treated with pegylated interferon alpha-2b and ribavirin

The aim of this study was to assess the association between liver stiffness measured by transient elastography (FibroScan) and the efficacy of pegylated interferon alpha-2b plus ribavirin combination treatment for patients with chronic hepatitis C virus (HCV) infection. We prospectively studied 145 Japanese patients with chronic HCV infection. FibroScan was done at baseline, at the end of treatment, and at 48 and 96 weeks after the end of treatment. The FibroScan values were significantly decreased for sustained virological response (SVR) patients (the mean rate of change; -16.2%, -32.2% and -43.5%) in comparison with non-SVR patients (-7.2%, -2.1% and +17.3%) at the end of treatment (P=0.0127), and 48 weeks (P<0.0001) and 96 weeks (P<0.0001) after the end of treatment. Among the non-SVR patients, the FibroScan values were significantly decreased for patients with biochemical response (BR) (-17.9%, -30.0% and -27.1%) in comparison with non-BR (-4.1%, +6.4% and +30.6%) at the end of treatment (P=0.0270), and 48 weeks (P<0.0001) and 96 weeks (P<0.0001) after the end of treatment. The FibroScan values may predict a progressively better clinical outcome for patients with successful virological and biochemical responses.

Electrochemical detection of hepatitis C virus based on site-specific DNA cleavage of BamHI endonuclease

We have developed a new electrochemical approach for qualitative and quantitative detection of hepatitis C virus (HCV) based on the site-specific DNA cleavage of BamHI endonuclease.

A novel diagnostic target in the hepatitis C virus genome

BACKGROUND

Detection and quantification of hepatitis C virus (HCV) RNA is integral to diagnostic and therapeutic regimens. All molecular assays target the viral 5'-noncoding region (5'-NCR), and all show genotype-dependent variation of sensitivities and viral load results. Non-western HCV genotypes have been under-represented in evaluation studies. An alternative diagnostic target region within the HCV genome could facilitate a new generation of assays.

METHODS AND FINDINGS

In this study we determined by de novo sequencing that the 3'-X-tail element, characterized significantly later than the rest of the genome, is highly conserved across genotypes. To prove its clinical utility as a molecular diagnostic target, a prototype qualitative and quantitative test was developed and evaluated multicentrically on a large and complete panel of 725 clinical plasma samples, covering HCV genotypes 1-6, from four continents (Germany, UK, Brazil, South Africa, Singapore). To our knowledge, this is the most diversified and comprehensive panel of clinical and genotype specimens used in HCV nucleic acid testing (NAT) validation to date. The lower limit of detection (LOD) was 18.4 IU/ml (95% confidence interval, 15.3-24.1 IU/ml), suggesting applicability in donor blood screening. The upper LOD exceeded 10(-9) IU/ml, facilitating viral load monitoring within a wide dynamic range. In 598 genotyped samples, quantified by Bayer VERSANT 3.0 branched DNA (bDNA), X-tail-based viral loads were highly concordant with bDNA for all genotypes. Correlation coefficients between bDNA and X-tail NAT, for genotypes 1-6, were: 0.92, 0.85, 0.95, 0.91, 0.95, and 0.96, respectively; X-tail-based viral loads deviated by more than 0.5 log10 from 5'-NCR-based viral loads in only 12% of samples (maximum deviation, 0.85 log10). The successful introduction of X-tail NAT in a Brazilian laboratory confirmed the practical stability and robustness of the X-tail-based protocol. The assay was implemented at low reaction costs (US$8.70 per sample), short turnover times (2.5 h for up to 96 samples), and without technical difficulties.

CONCLUSION

This study indicates a way to fundamentally improve HCV viral load monitoring and infection screening. Our prototype assay can serve as a template for a new generation of viral load assays. Additionally, to our knowledge this study provides the first open protocol to permit industry-grade HCV detection and quantification in resource-limited settings.

Abbott RealTime hepatitis C virus (HCV) and Roche Cobas AmpliPrep/Cobas TaqMan HCV assays for prediction of sustained virological response to pegylated interferon and ribavirin in chronic hepatitis C patients

Two commercial real-time PCR assays are currently available for sensitive hepatitis C virus (HCV) RNA quantification: the Abbott RealTime HCV assay (ART) and Roche Cobas AmpliPrep/Cobas TaqMan HCV assay (CAP/CTM). We assessed whether the two real-time PCR assays were more effective than Roche Cobas Amplicor HCV Monitor test, v.2.0 (CAM) for prediction of the sustained virological response (SVR) to pegylated interferon (PEG-IFN) plus ribavirin (RBV) in chronic hepatitis C. Sixty patients chronically infected with HCV genotype 1b (37 males and 23 females, 53 +/- 12 years of age) were treated with PEG-IFNalpha2b plus RBV for 48 weeks. Stored specimens at nine time points for each patient (at baseline, on treatment, and 24 weeks after treatment) were tested by the two real-time PCR assays and CAM. Twenty-six (43.3%) patients reached SVR. The positive predictive values (PPVs) for SVR of undetectable HCV RNA at week 12 by CAM, ART, and CAP/CTM were 74.3%, 88.0%, and 95.2%, respectively. An undetectable HCV RNA level by CAM, ART, and CAP/CTM correctly predicted SVR at week 4 in 100%, 100%, and 100% of patients, at weeks 5 to 8 in 91.7%, 100%, and 100% of patients, at weeks 9 to 12 in 55.6%, 75%, and 87.5% of patients, and at weeks 13 to 24 in 0%, 26.7%, and 40% of patients, respectively. Of 16 patients who relapsed after treatment, HCV RNA was detectable in 2 patients at the end of treatment by CAP/CTM but undetectable by ART and CAM. HCV RNA tests using ART and CAP/CTM are considered to be more effective at predicting SVR than CAM, and the PPV for SVR was slightly higher in CAP/CTM than in ART.

Prediction of virologic response in difficult-to-treat chronic hepatitis C patients during high-dose interferon induction therapy

OBJECTIVE

To determine (i) whether early viral kinetics or other markers during a modified treatment regimen are predictors of treatment outcome and (ii) whether fast responders can be treated for 24 weeks, without compromising the sustained virologic response (SVR) rate.

MATERIAL AND METHODS

One hundred "difficult-to-treat" chronic hepatitis C patients (46 previous non-responders/relapsers (any genotype), 54 treatment-naive patients genotypes 1 and 4) were treated with triple antiviral induction therapy: amantadine hydrochloride and ribavirin, combined with 6 weeks interferon alfa-2b induction (weeks 1-2: 18 MU/day, weeks 3-4: 9 MU/day, weeks 5-6: 6 MU/day), thereafter combined with weekly peginterferon alfa-2b. Fast responders (>or=3 log(10) HCV RNA decline at week 4) were randomized to 24 or 48 weeks. Slow responders (<3 log(10) HCV RNA decline at week 4) were treated for 48 weeks. Treatment was stopped in patients with detectable HCV RNA at week 24.

RESULTS

Thirty-six patients achieved SVR: 28 of 60 fast responders (47%) versus 8 of 32 slow responders (25%, p<0.05). Relapse rates among fast responders treated for 24 or 48 weeks were 27% and 20%, respectively (p=NS). SVR in fast responders was independent of baseline HCV RNA >or= or <600,000 IU/mL. All treatment-naive patients with HCV RNA <5 IU/mL at week 1 or 2 achieved SVR; all treatment-naive patients with HCV RNA >or=5 IU/mL at week 16 became non-SVR. In previous non-responders/relapsers, the predictive value for SVR was 83% if HCV RNA was <5 IU/mL at week 2; all previous non-responders/relapsers with HCV RNA >or=5 IU/mL at week 8 became non-SVR.

CONCLUSIONS

With high-dose interferon induction, SVR and non-SVR can be predicted reliably within 16 weeks. Fast responders can be treated for 24 weeks, and SVR is independent of baseline viral load in fast responders.

Kinetics of hepatitis C viral RNA and HCV-antigen during dialysis sessions: evidence for differential viral load reduction on dialysis

Hepatitis C infection is a common problem in dialysis units. The prevalence ranges from 3% to more than 50%. Several reports have described a variable reduction of HCV-RNA during hemodialysis treatment sessions. But so far nothing is known about the HCV antigenemia or the kinetics of the reduction of HCV-RNA and HCV antigenemia during these sessions. HCV-RNA was monitored using the VERSANT HCV bDNA assay 3.0 (Bayer Healthcare Diagnostics, Leverkusen, Germany) or the HCV-Monitor TaqMan (Roche Diagnostics). HCV antigenemia was tested by using Ortho-trac-C assay (Ortho Clinical Diagnostics, Neckargemünd, Germany). Kinetics of HCV-RNA were available in 15 dialysis sessions measured by bDNA assay and in 5 dialysis sessions measured by rt-PCR. Quantitative HCV-antigenemia was available in fourteen dialysis sessions. Not only HCV-RNA but as expected also the HCV-antigenemia fell during the dialysis session. However, while the average reduction of HCV-antigen appears steady and linear, the level of HCV-RNA seems to be stable during the first 3 hr of dialysis, and decreases rapidly during the last 2 hr. The results seem to be independent of the HCV-RNA detection method. The different kinetics of HCV RNA and HCV antigen load suggest that there are different mechanisms responsible for the reduction of the HCV antigen and HCV-RNA, respectively. Reduction of viral load during dialysis session indicates a potential benefit of dialysis in case of HCV associated antiviral therapy.

Effect of treatment with interferon alpha-2b and ribavirin in patients infected with genotype 2 hepatitis C virus

AIM

Nearly 20% of chronic hepatitis C (CHC) patients with genotype 2 hepatitis C virus (HCV) infection are not curable, even by interferon (IFN)-ribavirin combination therapy. The aim of this study is to investigate the factors that determine the efficacy of combination therapy in patients with genotype 2 HCV infection.

METHODS

Fifty patients with CHC who underwent a treatment of 6 MU IFN alpha-2b with ribavirin for 24 weeks were retrospectively analyzed.

RESULTS

All the patients showed no serum HCV-RNA within 12 weeks after starting the therapy. Forty-one of the 50 patients (82%) achieved a sustained virological response (SVR). The age, sex, genotype (2a vs. 2b) and grade/stage of the liver by histopathology and pretreatment viral load werenot different between the sustained responders and relapsers. Univariate analysis showed that an earlier viral clearance from blood and a larger number of amino acid substitutions in the interferon sensitivity determining region (ISDR) were predictors of SVR. Multivariate analysis showed that a large number of amino acid substitutions in the ISDR was a predictor of SVR.

CONCLUSION

The characterization of the amino acid sequences of ISDR may be helpful for predicting a relapse after combination therapy in patients with genotype 2 HCV infection.

Development of a TaqMan assay for the six major genotypes of hepatitis C virus: comparison with commercial assays

A quantitative real-time PCR assay was developed that detects genomic RNA from reference strains representing the six major genotypes of hepatitis C virus (HCV) with equal sensitivity and accurately measured HCV RNA in JFH1 HCV-infected Huh7.5 cells. The method is indirectly calibrated to the first international (WHO 96/790) HCV standard preparation and has a linear dynamic range of 10(2.6)-10(6.5) IU/ml. In addition, the inter- and intra-assay precision were approximately 3% CV and <2% CV, respectively. Comparison with results obtained by commercially available HCV RNA Nucleic Acid Technology kits (Versant HCV RNA 3.0 b-DNA and Amplicor HCV Monitor), that also employ the WHO standard, allowed validation of the TaqMan assay against all major HCV genotypes. Both commercial methods detected HCV RNA over a wide dynamic range, but showed a consistent difference of about 0.3 log10 when evaluating samples of different HCV genotypes. The genome titers obtained with the three methods correlated with the infectivity titers previously determined for the HCV reference strains. TaqMan assays have become an essential tool to follow viral load in clinical samples and cell culture-based experiments and this technology offers significant advantages in linear dynamic range, sensitivity and customization.

Blunted cytopenias and weight loss: new correlates of virologic null response to re-treatment of chronic hepatitis C

BACKGROUND & AIMS

Peginterferon with ribavirin therapy for chronic hepatitis C leads to sustained loss of serum hepatitis C virus (HCV) RNA in half of treated patients. Although viral kinetic profiles in treatment responders shed light on the mechanism of action of interferon and ribavirin, minimal information is available to explain why some patients experience little or no virologic suppression.

METHODS

We evaluated factors that might be associated with the lack of a week-20 virologic response in previous nonresponder patients undergoing peginterferon and ribavirin retreatment. Among 1145 patients enrolled in the Hepatitis C Antiviral Long-term Treatment against Cirrhosis Trial's lead-in treatment phase, 588 who received more than 80% of prescribed therapy for 20 weeks were analyzed.

RESULTS

By week 20, 245 patients (41.7%) had undetectable HCV RNA (full response), 186 (31.6%) had a 1 log(10) or greater decrease in HCV RNA (partial response), and 157 (26.7%) had less than a 1 log(10) decrease (null response) in HCV RNA. Null response was associated independently with African American race, genotype-1 infection, and less reduction in body weight, platelets, and white blood cells during treatment.

CONCLUSIONS

On-treatment variables associated with null response suggest a blunted systemic response to interferon. These observations have important implications for the design and analysis of trial results in which novel agents are evaluated. Further studies are needed to discern whether host interferon resistance, viral drug resistance, or both are playing a role in patients who have no virologic response to interferon treatment.

Assessment of hepatitis C virus-RNA clearance under combination therapy for hepatitis C virus genotype 1: performance of the transcription-mediated amplification assay

Monitoring of HCV-RNA in blood during antiviral therapy is performed mostly by commercially available reverse transcription polymerase chain reaction-based (RT-PCR) assays, with a lower detection limit of 30-50 IU/mL of HCV-RNA. Use of different tests in the pivotal trials of combination therapy has generated some discordance, in terms of predictive value of the early virological response (EVR). To evaluate whether the use of a more sensitive test, as a qualitative assay based on transcription mediated amplification (TMA) with a lower detection limit of 5-10 IU/mL of HCV-RNA, may obtain a better prediction of EVR and of the ultimate virological outcome, we retrospectively evaluated serial samples from 108 naïve patients with HCV genotype 1 chronic hepatitis, treated with pegylated alpha2b interferon plus ribavirin for 48 weeks and with a 24 weeks stopping rule. Serum samples of patients, obtained during treatment at weeks 4, 12, 24 and 48 and after treatment at week 24, were evaluated by TMA. Comparison of the RT-PCR and TMA assays for the qualitative detection of HCV-RNA showed no significant differences in performance when these tests were used at the end of the treatment period for assessing patients without an on-treatment virological response and those who eventually obtain a sustained virological response. Our results show instead that the use of TMA assay to detect HCV-RNA at 12 and 24 weeks of the combination therapy is more effective than RT-PCR in identifying patients with the highest probability of sustained HCV-RNA clearance.

Improved COBAS TaqMan hepatitis C virus test (Version 2.0) for use with the High Pure system: enhanced genotype inclusivity and performance characteristics in a multisite study

We have evaluated the COBAS TaqMan hepatitis C virus (HCV) test (version 2.0) for use with the High Pure system (HCVHPS V2), a new, revised real-time reverse transcription-PCR assay developed to improve the genotype quantitation of version 1.0 (HCVHPS V1). Revisions were made in the wash buffer and in the reverse transcription temperature. The genotype inclusivity of HCVHPS V2 was evaluated at three different sites, using HCVHPS V2, HCVHPS V1, and the COBAS AMPLICOR HCV MONITOR test (version 2.0) (CAHCM). The fully automated COBAS Ampliprep/COBAS TaqMan HCV test was also used in one of the participating laboratories. The mean differences in HCV RNA values between HCVHPS V2 and CAHCM and between HCVHPS V2 and HCVHPS V1 ranged from -0.21 to 0.13 log and from 0.24 to 1.27 log, respectively, with >0.5-log differences for genotypes 2, 3, 4, and 5. With a NIBSC panel of HCV genotypes 1 through 6, the measured HCVHPS V2 values were within 0.25 log of the nominal values for all 6 genotypes. When serial dilutions of genotype-specific clinical HCV specimens were tested, the assay showed a limit of detection between 10 and 20 IU/ml and a linear range of 25 IU/ml to 3.91 x 10(8) IU/ml. Clinical and analytical specificities of 100% were demonstrated with 100 HCV-seronegative specimens as well as with 12 non-HCV members of Flaviviridae and 22 additional microorganisms. These data indicate that HCVHPS V2 is a robust and accurate test for the quantitation of all six HCV genotypes and useful in monitoring viral load in all clinical HCV specimens.

Qualitative application of COBAS AMPLICOR HCV test version 2.0 assays in patients with chronic hepatitis C virus infection and comparison of clinical performance with version 1.0

The objective of this research was to investigate the clinical performance of COBAS AMPLICOR hepatitis C virus (HCV) test version 2.0 Assays (CA V2.0). Eight serial samples with standard HCV ribonucleic acid (RNA) concentration and 10 times serial dilution of the 500 IU/mL samples were tested in triplicate by CA V2.0 (the limit of detection was 50 IU/mL). HCV RNA was investigated with CA V2.0 in 220 specimens from 100 chronic hepatitis C (CHC) patients, 60 chronic hepatitis B patients, and 60 healthy blood donors. The sensitivity was 99% and the specificity was 98.3%. Sera of 84 naïve CHC patients receiving standard interferon plus ribavirin for 24 weeks were tested by CA V2.0 and CA V1.0 at weeks 2, 4 and 8. The positive detection rates of CA V2.0 were significantly higher than CA V1.0 at week 2 (60.7% vs. 51.2%; p < 0.01) and week 8 (27.4% vs. 21.4%; p < 0.05). At weeks 2, 4 and 8, the positive predictive values were 90.91%, 83.02% and 78.69% with CA V2.0, and 90.24%, 82.14% and 72.73% with CA V1.0. The negative predictive values were 58.82%, 77.42% and 86.96% with CA V2.0, and 67.44%, 82.14% and 83.33% with CA V1.0. However, there was no significant difference between CA V2.0 and CA V1.0 for predicting sustained virologic response.

Role of weight-based ribavirin dosing and extended duration of therapy in chronic hepatitis C in HIV-infected patients: the PRESCO trial

The response to pegylated interferon (pegIFN) plus ribavirin (RBV) as treatment of chronic hepatitis C virus (HCV) infection is lower in HIV-coinfected than in HCV-monoinfected patients and could be due to suboptimal RBV dosing and/or insufficient duration of therapy in prior trials. In a prospective, multicenter, open, comparative trial, HCV/HIV-coinfected patients received pegIFN plus weight-based RBV for 48 or 72 weeks (HCV genotypes 1 and 4) and 24 or 48 weeks (HCV genotypes 2 and 3). Use of didanosine was not allowed. Out of 389 patients included in the trial, 61% were infected by HCV-1/4 and 67% had serum HCV-RNA >500,000 IU/ml. Sustained virological response (SVR) was achieved by 49.6%, significantly higher in HCV-2/3 than HCV-1/4 (72.4% vs. 35%; p < 0.0001). A high drop-out rate in the longer treatment arms precluded obtaining definitive conclusions about the efficacy of prolonging therapy. Premature treatment discontinuations due to serious adverse events occurred in 8.2%. Infection with HCV-2/3, lower baseline HCV-RNA, and negative HCV-RNA at week 12 were all independent predictors of SVR in the multivariate analysis. The use of RBV 1000-1200 mg/day plus pegIFN is relatively safe and provides SVR in nearly half of coinfected patients, twice as high in HCV-2/3 than HCV-1/4.

Comparison of performance characteristics of three real-time reverse transcription-PCR test systems for detection and quantification of hepatitis C virus

We evaluated the performance characteristics of three real-time reverse transcription-PCR test systems for detection and quantification of hepatitis C virus (HCV) and performed a direct comparison of the systems on the same clinical specimens. Commercial HCV panels (genotype 1b) were used to evaluate linear range, sensitivity, and precision. The Roche COBAS TaqMan HCV test for research use only (RUO) with samples processed on the MagNA Pure LC instrument (Roche RUO-MPLC) and Abbott analyte-specific reagents (ASR) with QIAGEN sample processing (Abbott ASR-Q) showed a sensitivity of 1.0 log(10) IU/ml with a linear dynamic range of 1.0 to 7.0 log(10) IU/ml. The Roche ASR in combination with the High Pure system (Roche ASR-HP) showed a sensitivity of 1.4 log(10) IU/ml with a linear dynamic range of 2.0 to 7.0 log(10) IU/ml. All of the systems showed acceptable reproducibility, the Abbott ASR-Q being the most reproducible of the three systems. Seventy-six clinical specimens (50 with detectable levels of HCV RNA and various titers and genotypes) were tested, and results were compared to those of the COBAS Amplicor HCV Monitor v2.0. Good correlation was obtained for the Roche RUO-MPLC and Abbott ASR-Q (R(2) = 0.84 and R(2) = 0.93, respectively), with better agreement for the Abbott ASR-Q. However, correlation (R(2) = 0.79) and agreement were poor for Roche ASR-HP, with bias relative to concentration and genotype. Roche ASR-HP underestimated HCV RNA for genotypes 3 and 4 as much as 2.19 log(10) IU/ml. Our study demonstrates that Roche RUO-MPLC and Abbott ASR-Q provided acceptable results and agreed sufficiently with the COBAS Amplicor HCV Monitor v2.0.

Critical role of ribavirin for the achievement of early virological response to HCV therapy in HCV/HIV-coinfected patients

The response to hepatitis C virus (HCV) therapy seems to be lower in HCV/HIV-coinfected patients than in HCV-monoinfected individuals. Given that most pivotal trials conducted in coinfected patients have used the combination of pegylated interferon (pegIFN) along with fixed low doses (800 mg/day) of ribavirin (RBV), it is unclear whether HIV itself and/or suboptimal RBV exposure could explain this poorer outcome. Two well-defined end points of early virological response were evaluated in Peginterferon Ribavirina España Coinfección (PRESCO), a multicentre trial in which the combination of pegIFN plus RBV (1000 mg if body weight <75 kg and 1200 mg if >75 kg) was prescribed to coinfected patients. For comparisons, we used unpublished data from early kinetics in two other large trials, one performed in HIV-negative patients [Pegasys International Study Group (PISG)] in which RBV 1000-1200 mg/day was used and another [AIDS Pegasys Ribavirin Coinfection Trial (APRICOT)] in which HIV-positive patients received fixed low RBV doses (800 mg/day). A total of 348 HCV/HIV-coinfected patients from the PRESCO trial were analysed as well as all patients treated with pegIFN plus RBV, who completed 12 weeks of therapy in the comparative studies (435 in PISG and 268 in APRICOT). Negative serum HCV-RNA at week 4 (which has the highest positive predictive value of sustained virological response, SVR) was attained in 33.3%, 31.2% and 13% of treated patients with HCV genotype 1, respectively, in PRESCO, PISG and APRICOT. For HCV genotypes 2/3, responses were 83.7%, 84.2% and 37%, respectively. A decline lower than 2 log(10) at week 12 (which has the highest negative predictive value of SVR) was seen in 25.5%, 19.5% and 37% of HCV genotype-1-infected patients, and in 2.1%, 2.9% and 12% of genotypes-2/3-infected patients, respectively. Prescription of high RBV doses enhances the early virological response to HCV therapy in HCV/HIV-coinfected patients, with results approaching those seen in HCV-monoinfected patients.

Low-level HCV Viraemia after Initial Response during Antiviral Therapy: Transcription-Mediated Amplification Predicts Treatment Failure

Background

In chronic hepatitis C patients with an initial virological response (IVR) during antiviral therapy (that is, HCV RNA becomes negative before week 16 of treatment) the significance of reappearing viraemia below the detection limit of PCR is not known. We studied this phenomenon in subsets of patients.

Methods

We assessed HCV RNA at weeks 16 and 20 of therapy by PCR and by more sensitive transcription-mediated amplification (TMA) in 23 patients with breakthrough or relapse and in 34 patients with sustained virological response (SVR). All patients participated in a high-dose-interferon induction study for difficult-to-treat patients. Therapy consisted of amantadine hydrochloride and ribavirin, combined with interferon-α2b induction during the first 6 weeks and thereafter combined with weekly pegylated interferon-α2b.

Results

Among the 57 IVR patients, we detected transient or persistent reappearance of low levels of HCV RNA in 10 of the 23 (43%) patients with eventual breakthrough or relapse; but in none of the 34 SVR patients. In 5 of 10 patients reappearing HCV RNA was only detectable by TMA.

Conclusion

Reappearance of low levels of HCV RNA in patients with IVR predicts treatment failure.