Detection of residual hepatitis C virus RNA by transcription-mediated amplification in patients with complete virologic response according to polymerase chain reaction-based assays

Clinical diagnosis of viral hepatitis: Current status and future strategies

Viral hepatitis (VH) is a significant public health issue with tremendous potential to aggravate into chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. Recent decade has witnessed remarkable uprising in the drug development and effective treatment of VH. An upsurge is seen in identification of antiviral therapies with low rates of viral resistance, the improvement of Hepatitis B Virus (HBV) vaccination and the development of direct-acting antivirals for Hepatitis C Virus (HCV). But unfortunately, the "2030 worldwide eradication" objective of World Health Organization (WHO) is still unmet. It can be largely attributed to the deficit faced by the healthcare system concerning screening and diagnosis. A timely, accurate and comprehensive screening; encompassing maximum population coverage is essential to combat this disease. However, advancements in VH diagnostics remain inadequate and with a marginal use in routine practice. This paper deliberates upon the lacunae in traditional and prevailing diagnostic methodology of viral hepatitis, especially their inadequacy in meeting the unique situations prevailing low- and middle-income countries (LMIC).

Toward a next-generation diagnostic tool: A review on emerging isothermal nucleic acid amplification techniques for the detection of SARS-CoV-2 and other infectious viruses

As the COVID-19 pandemic continues to affect human health across the globe rapid, simple, point-of-care (POC) diagnosis of infectious viruses such as SARS-CoV-2 remains challenging. Polymerase chain reaction (PCR)-based diagnosis has risen to meet these demands and despite its high-throughput and accuracy, it has failed to gain traction in the rapid, low-cost, point-of-test settings. In contrast, different emerging isothermal amplification-based detection methods show promise in the rapid point-of-test market. In this comprehensive study of the literature, several promising isothermal amplification methods for the detection of SARS-CoV-2 are critically reviewed that can also be applied to other infectious viruses detection. Starting with a brief discussion on the SARS-CoV-2 structure, its genomic features, and the epidemiology of the current pandemic, this review focuses on different emerging isothermal methods and their advancement. The potential of isothermal amplification combined with the revolutionary CRISPR/Cas system for a more powerful detection tool is also critically reviewed. Additionally, the commercial success of several isothermal methods in the pandemic are highlighted. Different variants of SARS-CoV-2 and their implication on isothermal amplifications are also discussed. Furthermore, three most crucial aspects in achieving a simple, fast, and multiplexable platform are addressed.

RT-LAMP-Based Molecular Diagnostic Set-Up for Rapid Hepatitis C Virus Testing

Hepatitis C virus (HCV) infections occur in approximately 3% of the world population. The development of an enhanced and extensive-scale screening is required to accomplish the World Health Organization's (WHO) goal of eliminating HCV as a public health problem by 2030. However, standard testing methods are time-consuming, expensive, and challenging to deploy in remote and underdeveloped areas. Therefore, a cost-effective, rapid, and accurate point-of-care (POC) diagnostic test is needed to properly manage the disease and reduce the economic burden caused by high case numbers. Herein, we present a fully automated reverse-transcription loop-mediated isothermal amplification (RT-LAMP)-based molecular diagnostic set-up for rapid HCV detection. The set-up consists of an automated disposable microfluidic chip, a small surface heater, and a reusable magnetic actuation platform. The microfluidic chip contains multiple chambers in which the plasma sample is processed. The system utilizes SYBR green dye to detect the amplification product with the naked eye. The efficiency of the microfluidic chip was tested with human plasma samples spiked with HCV virions, and the limit of detection observed was 500 virions/mL within 45 min. The entire virus detection process was executed inside a uniquely designed, inexpensive, disposable, and self-driven microfluidic chip with high sensitivity and specificity.

Diagnosis for COVID-19: current status and future prospects

Introduction: Coronavirus disease 2019 (COVID-19), a respiratory illness caused by novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), had its first detection in December 2019 in Wuhan (China) and spread across the world. In March 2020, the World Health Organization (WHO) declared COVID-19 a pandemic disease. The utilization of prompt and accurate molecular diagnosis of SARS-CoV-2 virus, isolating the infected patients, and treating them are the keys to managing this unprecedented pandemic. International travel acted as a catalyst for the widespread transmission of the virus.Areas covered: This review discusses phenotype, structural, and molecular evolution of recognition elements and primers, its detection in the laboratory, and at point of care. Further, market analysis of commercial products and their performance are also evaluated, providing new ways to confront the ongoing global public health emergency.Expert commentary: The outbreak for COVID-19 created mammoth chaos in the healthcare sector, and still, day by day, new epicenters for the outbreak are being reported. Emphasis should be placed on developing more effective, rapid, and early diagnostic devices. The testing laboratories should invest more in clinically relevant multiplexed and scalable detection tools to fight against a pandemic like this where massive demand for testing exists.

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.

Enzyme-free, signal-amplified nucleic acid circuits for biosensing and bioimaging analysis

Enzyme-free, signal-amplified nucleic acid circuits utilize programmed assembly reactions between nucleic acid substrates to transduce a chemical input into an amplified detection signal.

Clinical laboratory assessments for Mycoplasma genitalium in a high-prevalence sexually-transmitted infection community reveal epidemiologic dichotomies with Trichomonas vaginalis

INTRODUCTION

Mycoplasma genitalium is an emerging agent of sexually-transmitted infection and is responsible for clinically-significant genital tract disease in both females and males. Similar to scenarios recently experienced with the urogenital flagellate Trichomonas vaginalis, an evolving molecular diagnostic reference standard based on transcription-mediated amplification allows for accurate detection of the organism, plus additional insight into disease epidemiology. Areas covered. The basis for this article includes primary peer-reviewed literature plus compilations of data derived from routine clinical laboratory screening of females and males for agents of sexually-transmitted infection. Introductory laboratory and epidemiologic data related to T. vaginalis provides not only a foreshadowing to the dichotomies inherent to M. genitalium prevalence but also advocacy of a common non-invasive specimen source that could be used to screen females for both agents. This review also documents increased prevalence rates of M. genitalium in both females and males by way of transcription-mediated amplification. Expert commentary. Molecular detection of M. genitalium should be a consideration in the development of comprehensive sexually-transmitted infection screening programs for both females and males. Transcription-mediated amplification has additionally identified novel facets of M. genitalium and T. vaginalis epidemiology that warrant further investigation.

Sicca syndrome and dementia in a patient with hepatitis C infection: a case report with unusual bifocal extrahepatic manifestations

INTRODUCTION

Hepatitis C virus (HCV) infections are associated with extrahepatic manifestations in 40-75 % of cases. Sialitis and secondary Sjögren syndrome are well characterized complications of chronic HCV infections but the mechanisms (primary or secondary) leading to xerostomia are not understood. Similarly, brain lesions due to HCV can be primary or secondary but the pathology of primary HCV-related brain lesions is not well described.

CASE REPORT

We report the postmortem case of a 60-year old patient initially presenting with sicca syndrome and dementia. HCV was identified in the brain but not in the salivary glands using transcription-mediated amplification (TMA). Focal sialitis was found in submandibular glands. Neuropathological examination revealed the presence of multiple dot-sized demyelination foci.

CONCLUSION

Sicca syndrome is a common concern in chronic HCV infections and may be due to secondary immune mechanisms (we could not isolate HCV in salivary gland tissues). TMA had never been applied to the detection of viruses in salivary glands and neural tissues and proves to be a promising technique. Neuropathological reports in HCV infections are rare and the lesions we report may be the first characterization of the direct effect of HCV on brain cells. More cases are needed to define the full spectrum of lesions potentially caused by the direct action of the HCV on salivary glands and neural tissues.

[To consider negative viral loads below the limit of quantification can lead to errors in the diagnosis and treatment of hepatitis C virus infection]

INTRODUCTION

For years many clinical laboratories have routinely classified undetectable and unquantifiable levels of hepatitis C virus RNA (HCV-RNA) determined by RT-PCR as below limit of quantification (BLOQ). This practice might result in erroneous clinical decisions.

AIM

To assess the frequency and clinical relevance of assuming that samples that are BLOQ are negative.

MATERIAL AND METHOD

We performed a retrospective analysis of RNA determinations performed between 2009 and 2011 (Cobas/Taqman, lower LOQ: 15 IU/ml). We distinguished between samples classified as «undetectable» and those classified as «<1.50E+01IU/mL» (BLOQ).

RESULTS

We analyzed 2.432 HCV-RNA measurements in 1.371 patients. RNA was BLOQ in 26 samples (1.07%) from 23 patients (1.68%). BLOQ results were highly prevalent among patients receiving Peg-Riba: 23 of 216 samples (10.6%) from 20 of 88 patients receiving treatment (22.7%). The clinical impact of BLOQ RNA samples was as follows: a) 2 patients initially considered to have negative results subsequently showed quantifiable RNA; b) 8 of 9 patients (88.9%) with BLOQ RNA at week 4 of treatment later showed sustained viral response; c) 3 patients with BLOQ RNA at weeks 12 and 48 of treatment relapsed; d) 4 patients with BLOQ RNA at week 24 and/or later had partial or breakthrough treatment responses, and e) in 5 patients the impact were null or could not be ascertained.

CONCLUSIONS

This study suggests that BLOQ HCV-RNA indicates viremia and that equating a BLOQ result with a negative result can lead to treatment errors. BLOQ results are highly prevalent in on-treatment patients. The results of HCV-RNA quantification should be classified clearly, distinguishing between undetectable levels and levels that are BLOQ.

Transcription-mediated amplification (TMA) for the assessment of viremia in hemodialysis patients with hepatitis C

The diagnosis of hepatitis C virus (HCV) infection in hemodialysis patients is difficult particularly due to the presence of intermittent viremia. The aims of this study were: (a) to determine the prevalence of intermittent viremia in hemodialysis patients with anti-HCV antibodies who tested negative for HCV RNA by PCR at the first evaluation and (b) to evaluate the contribution of the transcription-mediated amplification method (TMA) to the diagnosis of viremia in the PCR-negative samples. One hundred and six patients with anti-HCV antibodies and an initial negative result for HCV RNA by PCR were included. An additional sample was collected for a second HCV RNA test by PCR after a minimum interval of 3 months and a positive result characterized intermittent viremia. HCV RNA was investigated by TMA in the PCR-negative sample of patients with intermittent viremia, and in the most recent sample from patients with PCR-negative results in both determinations. Intermittent viremia was observed in 60/106 (57%) patients (57% men; age: 45 ± 10 years). Fifty-one of the 60 negative samples from patients with intermittent viremia and 29/46 double-negative patients were tested by TMA. This assay detected viremia in 20/51 (39%) samples of intermittent viremia and in 2/29 (7%) of double-negative samples. The results showed that intermittent viremia is frequent in hemodialysis patients who tested negative for HCV RNA by PCR. Therefore, a second HCV RNA test is necessary for all HCV RNA-negative patients. The TMA assay appears to be the best first screening test for viremia in this population.

HCV infection among Saudi population: high prevalence of genotype 4 and increased viral clearance rate

HCV is a major etiological agent of liver disease with a high rate of chronic evolution. The virus possesses 6 genotypes with many subtypes. The rate of spontaneous clearance among HCV infected individuals denotes a genetic determinant factor. The current study was designed in order to estimate the rate of HCV infection and ratio of virus clearance among a group of infected patients in Saudi Arabia from 2008 to 2011. It was additionally designed to determine the genotypes of the HCV in persistently infected patients. HCV seroprevalence was conducted on a total of 15,323 individuals. Seropositive individuals were tested by Cobas AmpliPrep/Cobas TaqMan HCV assay to determine the ratio of persistently infected patients to those who showed spontaneous viral clearance. HCV genotyping on random samples from persistently infected patients were conducted based on the differences in the 5'untranslated region (5'UTR). Anti-HCV antibodies were detected in 7.3% of the totally examined sera. A high percentage of the HCV infected individuals experienced virus clearance (48.4%). HCV genotyping revealed the presence of genotypes 1 and 4, the latter represented 97.6% of the tested strains. Evidences of the widespread of the HCV genotype 4 and a high rate of HCV virus clearance were found in Saudi Arabia.

Clinical significance of discordant positive hepatitis C virus transcription-mediated amplification following end of treatment response

BACKGROUND

Polymerase chain reaction (PCR) assays are the standard for detecting hepatitis C virus viremia. The transcription-mediated amplification (TMA)-based assay is more sensitive.

METHODS

We retrospectively reviewed the charts of patients with a post-end of treatment (EOT) PCR-/TMA+ result to assess the clinical significance of a positive TMA result after a PCR negative EOT response or sustained viral response (SVR). Patients were divided into Group 1: PCR-/TMA+ after EOT response but during 24 week follow-up (n = 4); and Group 2: PCR-/TMA+ after SVR (n = 11).

RESULTS

All Group 1 patients achieved SVR. No Group 2 patients became PCR positive or had a rise in ALT. The TMA subsequently became negative in 6/7 patients with follow-up evaluation.

CONCLUSIONS

A discordant positive TMA post-EOT response or SVR did not seem to be clinically significant. This finding supports the possibility that patients with SVR have an acquired immune surveillance that prevents low-level viremia from progressing to clinical relapse.

Sample pretreatment and nucleic acid-based detection for fast diagnosis utilizing microfluidic systems

Recently, micro-electro-mechanical-systems (MEMS) technology and micromachining techniques have enabled miniaturization of biomedical devices and systems. Not only do these techniques facilitate the development of miniaturized instrumentation for biomedical analysis, but they also open a new era for integration of microdevices for performing accurate and sensitive diagnostic assays. A so-called “micro-total-analysis-system”, which integrates sample pretreatment, transport, reaction, and detection on a small chip in an automatic format, can be realized by combining functional microfluidic components manufactured by specific MEMS technologies. Among the promising applications using microfluidic technologies, nucleic acid-based detection has shown considerable potential recently. For instance, micro-polymerase chain reaction chips for rapid DNA amplification have attracted considerable interest. In addition, microfluidic devices for rapid sample pretreatment prior to nucleic acid-based detection have also achieved significant progress in the recent years. In this review paper, microfluidic systems for sample preparation, nucleic acid amplification and detection for fast diagnosis will be reviewed. These microfluidic devices and systems have several advantages over their large-scale counterparts, including lower sample/reagent consumption, lower power consumption, compact size, faster analysis, and lower per unit cost. The development of these microfluidic devices and systems may provide a revolutionary platform technology for fast sample pretreatment and accurate, sensitive diagnosis.

Three-year history of transcription-mediated amplification-based Trichomonas vaginalis analyte-specific reagent testing in a subacute care patient population

A total of 7,899 specimens submitted for live clinical Trichomonas vaginalis analyte-specific reagent (ASR) screening from 2008 to 2010 were audited on the basis of patient gender, specimen source, molecular Neisseria gonorrhoeae and Chlamydia trachomatis results, and relative light unit (RLU) data yielded by T. vaginalis ASR. Only 1.4% of the screening was ordered by emergency department clinicians. The screening volume in 2010 was 126% higher than that in 2008. The proportions of annual female and male screening remained consistent throughout the 3-year interval (∼92 and 8%, respectively). Although 71.8 and 9.5% of screening was performed on endocervical and vaginal specimens, respectively, over the 3-year period, no significant difference was noted in the T. vaginalis detection rates (8.9 and 8.6%, P = 0.85). Increased T. vaginalis detection was derived from female urine specimens (12.6%) compared to female genital swabs (P = 0.0004). The proportion of female urine screening increased during the 3-year interval (P < 0.0002). T. vaginalis detection rate in males was 6.6%, with no difference between urethral and urine T. vaginalis detection (P = 0.53). The mean RLU value for 714 positive specimens was 3,971,441; analogous values for each female specimen source and combined male source testing showed no variance (P ≥ 0.29). Combined-gender T. vaginalis detection rate (9.1%) was significantly greater than those of C. trachomatis (5.9%) and N. gonorrhoeae (1.5%; P < 0.0002). Equivocal results presented at a rate of 0.4%. T. vaginalis ASR is an increasingly utilized assay that yields higher detection rates than other sexually transmitted infection etiologies in this community subacute care setting.

Discordance between HCV RNA assays for week 24 HCV RNA determination during pegylated interferon-α/ribavirin treatment for chronic hepatitis C

BACKGROUND

The development of more sensitive HCV RNA assays might necessitate re-evaluation of the rules for stopping treatment (for example, HCV RNA negativity at week 24 during treatment with pegylated interferon-α and ribavirin for chronic hepatitis C). The aim of this study was to assess discordance between the week 24 HCV RNA test results of two PCR-based assays (Amplicor and TaqMan) and the transcription-mediated amplification (TMA) HCV RNA qualitative assay.

METHODS

A total of 89 week 24 samples that were negative using PCR-based assays during treatment were retested with the TMA qualitative assay to investigate discordance between tests results. All week 24 samples were HCV RNA negative by Amplicor or by TaqMan.

RESULTS

Of the 89 patients, 46 (52%) achieved sustained virological response (SVR). Viral breakthrough or relapse occurred in 43 patients (48%). All 89 HCV RNA negative week 24 samples were retested with the qualitative TMA assay. Eleven out of 89 samples had detectable HCV RNA (12%). All patients with detectable HCV RNA experienced breakthrough or relapse (negative predictive value 100%). Of the 78 patients with undetectable HCV RNA at week 24 using the TMA assay, 46 achieved SVR. This resulted in a positive predictive value (PPV) of 59% for the TMA assay compared with a PPV of 52% for the PCR-based assays.

CONCLUSIONS

All patients with detectable HCV RNA at week 24 using the TMA assay eventually relapsed. On the basis of these results, the use of this more sensitive HCV RNA assay could lead to the prevention of unnecessary treatment.

Molecular Diagnosis of Sexually Transmitted Chlamydia trachomatis in the United States

Chlamydia, with its Chlamydia trachomatis etiology, is the most common bacterial sexually transmitted infection in the United States and is often transmitted via asymptomatic individuals. This review summarizes traditional and molecular-based diagnostic modalities specific to C. trachomatis. Several commercially available, FDA-approved molecular methods to diagnose urogenital C. trachomatis infection include nucleic acid hybridization, signal amplification, polymerase chain reaction, strand displacement amplification, and transcription-mediated amplification. Molecular-based methods are rapid and reliable genital specimen screening measures, especially when applied to areas of high disease prevalence. However, clinical and analytical sensitivity for some commercial systems decreases dramatically when testing urine samples. In vitro experiments and clinical data suggest that transcription-mediated amplification has greater analytical sensitivity than the other molecular-based methods currently available. This difference may be further exhibited in testing of extragenital specimens from at-risk patient demographics. The development of future molecular testing could address conundrums associated with confirmatory testing, medicolegal testing, and test of cure.

Hepatitis C virus RNA assays: current and emerging technologies and their clinical applications

Molecular diagnostic assays represent a cornerstone in the management of hepatitis C virus (HCV) patients. Qualitative and quantitative HCV molecular assays are used for the diagnosis of acute and chronic HCV infections, viral genotyping, viral-load determination, treatment monitoring and prognosis. Reverse-transcription PCR, transcription-mediated amplification and branched DNA amplification are commonly employed for detection of HCV RNA. Recently, new HCV molecular assays that employ nanostructures have emerged and have been proposed as suitable for both low- and high-resource settings, without sacrificing sensitivity and specificity. This article will present current and future HCV molecular diagnostic assays with a focus on their clinical applications.

How to use virological tools for the optimal management of chronic hepatitis C

Approximately 180 million individuals are chronically infected with hepatitis C, which is strongly associated with the development of cirrhosis, end-stage liver disease and hepatocellular carcinoma. Several virological tools (anti-HCV antibody assays, measurement of HCV-RNA, HCV-genotyping) are useful in management of hepatitis C infected patients. The primary goal of antiviral therapy in chronic hepatitis C is a sustained virological response (SVR). The HCV genotype should be determined in every patient considered for antiviral therapy because the currently recommended treatment duration and ribavirin doses differ among HCV genotypes. Exact subtyping might gain increased importance for future therapies with direct-acting antiviral agents (DAA) because of differences of antiviral activities and barriers to resistance among HCV subtypes. Monitoring HCV RNA by a highly sensitive assay (LOD ≤ 15 IU/ml) is the basis for management of response guided therapy of chronic hepatitis C with pegylated IFN plus ribavirin. Rules for early discontinuation of antiviral therapy in non-responders and determination of optimal treatment durations in virologic responders have been developed for application of individualized treatment strategies.

Improved detection of hepatitis C virus infection by transcription-mediated amplification technology in dialysis population

BACKGROUND

Hepatitis C virus (HCV) infection remains common among patients undergoing maintenance dialysis and plays an adverse effect on survival in this population. Accurate detection of HCV viremia (HCV RNA) in dialysis patients requires a sensitive and specific diagnostic test.

METHODS

The Versant HCV RNA Qualitative Assay, based on transcription-mediated amplification (TMA) technique, was prospectively evaluated in 112 dialysis patients. Performance characteristics of the Versant HCV TMA Assay were evaluated in comparison to the Amplicor((R)) 2.0 HCV test based on polymerase chain reaction (PCR) technique. In addition, anti-HCV serologic tests including third-generation enzyme immunoassay and Recombinant Immunoblot Assay were performed.

RESULTS

Of the 112 specimens tested, 29 were reactive by Versant HCV TMA Assay, yielding an overall prevalence of HCV viremia of 25.9%. The concordance between TMA and PCR techniques was excellent [91% (101/112)]. Eleven specimens (10%) were invalid or equivocal by PCR due to interference phenomena; all 11 specimens had valid TMA results (2 patients being TMA reactive and 9 nonreactive). Four specimens [3.6% (4/112)] that tested PCR-negative and HCV TMA nonreactive were anti-HCV seropositive, consistent with resolved HCV infection. In the group of seronegative samples, one was reactive by TMA Assay [1.25% (1/80)].

CONCLUSIONS

The HCV TMA technology seems a highly sensitive tool for detecting HCV RNA in the dialysis population, with no evidence of specimen interference. One EIA-negative but HCV-RNA-positive patient by Versant HCV TMA Assay was identified. Prospective clinical trials are under way to assess the clinical impact related to the use of HCV TMA technology in dialysis population.

An overview about hepatitis C: a devastating virus

Hepatitis C (HCV) is the disease that has affected around 200 million people globally. HCV is a life threatening human pathogen, not only because of its high prevalence and worldwide burden but also because of the potentially serious complications of persistent HCV infection. Chronicity of the disease leads to cirrhosis, hepatocellular carcinoma and end-stage liver disease. HCV positive hepatocytes vary between less than 5% and up to 100%, indicating the high rate of replication of viral RNA. HCV has a very high mutational rate that enables it to escape the immune system. Viral diversity has two levels; the genotypes and Quasiaspecies. Major HCV genotypes constitute genotype 1, 2, 3, 4, 5 and 6 while more than 50 subtypes are known. All HCV genotypes have their particular patterns of geographical distribution and a slight drift in viral population has been observed in some parts of the globe.

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.

Twelve weeks posttreatment follow-up is as relevant as 24 weeks to determine the sustained virologic response in patients with hepatitis C virus receiving pegylated interferon and ribavirin

A sustained virologic response (SVR) in patients with chronic hepatitis C receiving pegylated interferon (PEG-IFN) plus ribavirin is defined as undetectable serum HCV-RNA at 24 weeks (W+24) posttreatment follow-up. Viral load outcome in patients with virological relapse (VR) has not been explored. This study evaluated whether the assessment of serum HCV-RNA 12 weeks (W+12) after the end of treatment was as relevant as W+24 to evaluate SVR in 573 patients who received combination PEG-IFN and ribavirin and had a virological response at the end of treatment. Serum HCV-RNA was measured, using a new assay based on transcription-mediated amplification (TMA) with a lowest detection limit of 5-10 IU/mL, at W+12 and W+24 after the end of treatment. VR was defined as reappearance of detectable HCV-RNA at W+24 posttreatment follow-up. The positive predictive value (PPV) of undetectable serum HCV-RNA at W+12 was evaluated to identify patients with SVR, and the viral load outcome was measured in relapse patients. At the W+24 posttreatment follow-up, 408 (71%) patients had an SVR, 181 (71.2%) were treated with PEG-IFNalpha-2a and ribavirin, and 227 (71.1%) were treated with PEG-IFNalpha-2b and ribavirin. At W+12, serum HCV-RNA was undetectable in 409 patients, and 408 patients were SVR (PPV 99.7%, 95% confidence interval 99.1-100). In relapse patients, serum HCV-RNA levels were 5.623 +/- 0.748, 4.979 +/- 0.870, and 5.216 +/- 0.758 log(10) IU/mL at baseline, W+12, and W+24, respectively.

CONCLUSION

Our results show that the assessment of serum HCV-RNA 12 weeks after the end of treatment, using the highly sensitive TMA assay (PPV 99.7%), is as relevant as after 24 weeks to predict SVR and make decisions on the management of treated patients, suggesting a new definition for SVR.

Visualizing hepatitis C virus infections in human liver by two-photon microscopy

BACKGROUND & AIMS

Although hepatitis C virus (HCV) is a common cause of cirrhosis and liver cancer, efforts to understand the pathogenesis of HCV infection have been limited by the low abundance of viral proteins expressed within the liver, which hinders the detection of infected cells in situ. This study evaluated the ability of advanced optical imaging techniques to determine the extent and distribution of HCV-infected cells within the liver.

METHODS

We combined 2-photon microscopy with virus-specific, fluorescent, semiconductor quantum dot probes to determine the proportion of hepatocytes that were infected with virus in frozen sections of liver tissue obtained from patients with chronic HCV infection.

RESULTS

Viral core and nonstructural protein 3 antigens were detected readily in liver tissues from patients with chronic infection without confounding tissue autofluorescence. Specificity was confirmed by blocking with specific antibodies and by tissue colocalization of distinct viral antigens. Between 7% and 20% of hepatocytes were infected in patients with plasma viral RNA loads of 10(5) IU/mL or greater. Infected cells were in clusters, which suggested spread of the virus from cell to cell. Double-stranded RNA, a product of viral replication, was abundant within cells at the center of such clusters, but often scarce in cells at the periphery, consistent with more recent infection of cells at the periphery.

CONCLUSIONS

Two-photon microscopy provides unprecedented sensitivity for the detection of HCV proteins and double-stranded RNA. Studies using this technology indicate that HCV infection is a dynamic process that involves a limited number of hepatocytes. HCV spread between cells is likely to be constrained by host responses.

Clinical performances of two real-time PCR assays and bDNA/TMA to early monitor treatment outcome in patients with chronic hepatitis C

BACKGROUND

Early viral monitoring is essential for the management of treatment outcome in patients with chronic hepatitis C. A variety of commercially available assays are now available to quantify HCV-RNA in routine clinical practice.

OBJECTIVES

Compare the clinical results of 3 commercially available assays to evaluate the positive predictive value (PPV) and the negative predictive value (NPV) of rapid virological response (RVR) at week 4 and early virological response (EVR) at week 12.

STUDY DESIGN

287 patients treated with standard care regimen combination therapy were studied. HCV-RNA values measured at baseline, week 4, week 12 with VERSANT HCV 3.0 Assay (bDNA), and VERSANT HCV-RNA Qualitative Assay (TMA) (bDNA/TMA); COBAS Ampliprep/COBAS/TaqMan (CAP/CTM) and Abbott m2000sp extraction/m2000rt amplification system (ART). RVR was defined as undetectable serum HCV-RNA and EVR as a > OR =2 log decline in baseline viral load (BLV).

RESULTS

Median (range) BVLs were: 5.585(2.585-6.816), 5.189(2.792-7.747) and 4.804(2.380-6.580) log(10)IU/ml, with bDNA/TMA, CAP/CTM and ART, respectively (p<0.01); RVR was observed in 22%, 30% and 27% of the patients and PPVs were 97%, 91% and 94% with bDNA/TMA, CAP/CTM and ART, respectively (p=0.317). EVR was observed in 76%, 73% and 67% of the patients and NPVs were 93%, 83% and 79% with bDNA/TMA, CAP/CTM and ART, respectively (p=0.09).

CONCLUSIONS

Treatment monitoring should include both detection of serum HCV-RNA at week 4 to predict SVR and at week 12 to predict non-SVR. The value of all 3 assays was similar for evaluating RVR or EVR. Because of viral load discrepancies the same assay should be used throughout patient treatment follow-up.

Virological response at 4 weeks to predict outcome of hepatitis C treatment with pegylated interferon and ribavirin

Background

Viral kinetics during therapy provides information on how to individualize treatment. To determine the benefit of assessing positive predictive values (PPVs) and negative predictive values (NPVs) of rapid virological responses (RVRs) and early virological responses (EVRs), on-treatment outcomes in chronic hepatitis C patients were examined.

Methods

A total of 408 patients (221 treatment-naive) treated with pegylated interferon-α2b and ribavirin were included. Hepatitis C virus (HCV) RNA was measured at baseline, 4 weeks and 12 weeks. RVR was defined as undetectable HCV RNA at 4 weeks and EVR as ≥2 log10 decrease in HCV RNA at 12 weeks. The additive value of RVR on predicting sustained virological response (SVR) was assessed with receiver operating characteristic (ROC) curves.

Results

SVR, RVR and EVR were observed in 46%, 23% and 78% of patients, respectively. PPVs of RVR were 96%, 100% and 100% in treatment-naive patients, relapsers and non-responders, respectively. NPVs of failure to achieve EVR were 97%, 75% and 91%, in treatment- naive patients, relapsers and non-responders, respectively. At 4 weeks, patients with RVR had the highest probability to achieve SVR (odds ratio 44.98 in the entire population and 32.95 in treatment-naive patients). ROC curves showed the area under the ROC curve to be 0.758 versus 0.832 in the entire population and 0.795 versus 0.858 in treatment-naive patients at baseline versus week 4, respectively.

Conclusions

RVR is a strong predictor of SVR (PPV>96%) and failure to achieve EVR is a strong predictor of non-SVR (NPV>75%), independent of patients’ pretreatment status. Added to baseline characteristics, RVR increased the accuracy to predict SVR. The combination of RVR and EVR provided complementary information, and thus provides a key opportunity to individualize treatment and improve the benefit/risk ratio of therapy.

Elevations in alanine aminotransferase levels late in the course of antiviral therapy in hepatitis C virus RNA-negative patients are associated with virological relapse

The incidence and clinical meaning of elevated alanine aminotransferase (ALT) in chronic hepatitis C patients who are hepatitis C virus (HCV)-RNA negative during pegylated interferon (PEG-IFN) and ribavirin therapy have not been completely characterized. In this study our aim was to assess the incidence, pattern, predictive factors, and clinical meaning of elevated ALT in a cohort of 173 chronic hepatitis C patients who obtained viral clearance during either PEG-IFNalpha2(a) or alpha2(b) and weight-based ribavirin therapy. Patients were defined sustained viral responders (SVRs) or relapser responders (RRs) on the basis of a serum HCV-RNA result at 24-week follow-up. SVR and RR were obtained in 141 (58%) and 32 patients (13%), respectively. Among the 173 study patients, 57 patients (33%) had undetectable serum HCV-RNA and elevated ALT in at least one evaluation (weeks 2, 4, 12, 24 in all genotypes, and week 48 in HCV genotype 1 and 4 alone), and this phenomenon was not differently distributed between SVRs and RRs. No pretreatment demographic (age, gender), clinical (ALT levels, histological grade and stage, body mass index) and viral (load, genotype) parameter was associated with this phenomenon. The incidence of elevated ALT levels was not associated with type of PEG-IFN and ribavirin dose. Elevated ALT levels showed a different longitudinal pattern, occurring more frequently between week 12 and the end of treatment in RR as compared to SVR patients (90% versus 9%, P = 0.000001).

CONCLUSION

The occurrence of elevated ALT levels in HCV-RNA-negative patients during PEG-IFN and ribavirin therapy is a fairly frequent and unpredictable phenomenon. Although ALT elevation per se is not associated with a greater risk of relapse, its occurrence in the later phases of therapy is more common in relapsing patients.

Sustained virological response is associated with clearance of hepatitis C virus RNA and a decrease in hepatitis C virus antibody

BACKGROUND/AIM

Viral eradication in chronic hepatitis C patients with sustained virological response (SVR) after interferon (IFN) therapy remains controversial.

METHODS

During a long-term follow-up study, 157 patients with SVR to IFN-alpha-2b-based therapy were investigated with a transcription-mediated amplification (TMA) assay in serum. The hepatitis C virus (HCV) antibody was assessed by measuring the optical density (OD) (Axsym HCV v3.0) and the semiquantitative titres (RIBA HCV v3.0) of the HCV antibodies directed against the core, NS3, NS4 and NS5 proteins. A control group included 23 untreated patients with persistently normal serum alanine aminotransferase and detectable serum HCV-RNA.

RESULTS

The median duration of follow-up was 4.0 (0-10) years. Serum HCV-RNA remained undetectable in all patients. The mean HCV antibody OD were 93 +/- 19 and 45 +/- 21 before therapy and in the last available serum sample respectively (P=0.001). There was a marked decrease in the HCV antibodies directed against the NS3, NS4 and NS5 proteins (P=0.001), while the core protein titre remained strongly positive. The 23 control patients were followed for a median of 5 (2-14) years. The mean HCV antibody OD were 65 +/- 14 and 64 +/- 19 in the first and the last measurements, respectively (NS), and HCV antibody titres for structural and non-structural proteins remained unchanged.

CONCLUSION

This long-term study evaluating 157 patients demonstrated that SVR assessed by TMA is durable, and HCV antibodies were markedly decreased (mainly those directed against the non-structural proteins), emphasizing an absence of ongoing infection. These results strongly suggest that HCV infection cured in patients who achieve an SVR.

Clinical performance evaluation of four automated chemiluminescence immunoassays for hepatitis C virus antibody detection

Various automated chemiluminescence immunoassay (CLIA) analyzers for the detection of antibodies to hepatitis C virus (HCV) are now commercially available in clinical laboratories and are replacing conventional enzyme immunoassays. We investigated the performance of four anti-HCV CLIAs (the Architect Anti-HCV assay on the Architect i2000 system, the Vitros Anti-HCV assay on the Vitros ECiQ Immunodiagnostic System, the Access HCV Ab PLUS assay on the UniCel DxI 800 analyzer, and the newly developed Elecsys Anti-HCV assay on the Cobas e 411 analyzer). The total percent coefficient of variation values of imprecision were 3.5 to 5.7% with positive control materials and 7.2 to 10.2% with negative control materials. The agreement between the results of the Elecsys, Architect, Vitros, and Access CLIAs ranged from 94.5 to 98.1%. The clinical sensitivity of all CLIAs was 100%. Each CLIA showed excellent reproducibility and clinical sensitivity. The Elecsys, Architect, Vitros, and Access CLIAs showed clinical specificities of 98.2, 98.8, 96.5, and 98.2%.

Interpretation of positive transcription-mediated amplification test results from polymerase chain reaction-negative samples obtained after treatment of chronic hepatitis C

The Siemens VERSANT transcription-mediated amplification (TMA) assay is extremely sensitive for the detection of hepatitis C virus (HCV) RNA in serum. Eleven of 180 subjects in the Hepatitis C Antiviral Long-term Treatment against Cirrhosis (HALT-C) Trial who achieved polymerase chain reaction (PCR)-defined sustained virological response (SVR) at week 72 also had TMA-positive results from the same blood draw; six were positive on repeat testing. We report the follow-up on these 11 patients, and the reproducibility of TMA test results from PCR-negative samples in relationship to antiviral treatment outcome. Peginterferon and ribavirin treatment was initiated in 1145 prior interferon nonresponders with advanced hepatic fibrosis. Treatment was continued for 48 weeks if patients had undetectable HCV RNA by PCR at treatment week 20. Frozen serum samples from weeks 12, 20, 24, 48, and 72 were subsequently tested by TMA. Nine of the 11 patients returned for testing (median, 30 months after the week 72 visit), and all had undetectable HCV RNA by TMA and PCR. Among 759 PCR-negative samples obtained during treatment that were tested twice by TMA, 17% overall exhibited consistently positive results, and 21% exhibited inconsistently positive results. SVR was more likely if TMA was consistently negative than if consistently or inconsistently positive. With continued treatment, patients with inconsistently positive TMA results were more likely to become TMA-negative than TMA-positive (P < 0.0001).

CONCLUSION

In PCR-negative samples, positive TMA results may indicate the presence of low levels of HCV RNA. However, because patients with positive TMA results may achieve SVR, management decisions during therapy should not be based on a single positive TMA test result.

Differences between two real-time PCR-based hepatitis C virus (HCV) assays (RealTime HCV and Cobas AmpliPrep/Cobas TaqMan) and one signal amplification assay (Versant HCV RNA 3.0) for RNA detection and quantification

Hepatitis C virus (HCV) RNA detection and quantification are the key diagnostic tools for the management of hepatitis C. Commercially available HCV RNA assays are calibrated to the HCV genotype 1 (gt1)-based WHO standard. Significant differences between assays have been reported. However, it is unknown which assay matches the WHO standard best, and little is known about the sensitivity and linear quantification of the assays for non-gt1 specimens. Two real-time reverse transcriptase PCR-based assays (RealTime HCV and Cobas Ampliprep/Cobas TaqMan HCV [CAP/CTM]) and one signal amplification-based assay (the Versant HCV RNA, version 3.0, branched DNA [bDNA] assay) were compared for their abilities to quantify HCV RNA in clinical specimens (n = 65) harboring HCV isolates of gt1 to g5. The mean differences in the amounts detected by RealTime HCV in comparison to those detected by the bDNA assay and CAP/CTM were -0.02 and 0.72 log(10) IU/ml HCV RNA, respectively, for gt1; -0.22 and 0.03 log(10) IU/ml HCV RNA, respectively, for gt2; -0.27 and -0.22 log(10) IU/ml HCV RNA, respectively, for gt3; -0.19 and -1.27 log(10) IU/ml HCV RNA, respectively, for gt4; and -0.03 and 0.09 log(10) IU/ml HCV RNA, respectively, for gt5. The lower limits of detection for RealTime HCV and CAP/CTM were 16.8 and 10.3 IU/ml, respectively, for the WHO standard and in the range of 4.7 to 9.0 and 3.4 to 44.4 IU/ml, respectively, for clinical specimens harboring gt1 to gt6. Direct comparison of the two assays with samples of the WHO standard (code 96/798) with high titers yielded slightly smaller amounts by RealTime HCV (-0.2 log(10) at 1,500 IU/ml and -0.3 log(10) at 25,000 IU/ml) and larger amounts by CAP/CTM (0.3 log(10) at 1,500 IU/ml and 0.2 log(10) at 25,000 IU/ml). Finally, all three tests were linear between 4.0 x 10(3) and 1.0 x 10(6) IU/ml (correlation coefficient, >or=0.99). In conclusion, the real-time PCR based assays sensitively detected all genotypes and showed comparable linearities for the quantification of HCV RNA, with the exception of gt1 and gt4. The previously reported differences in the absolute quantification of samples harboring gt1 were confirmed and may be explained by different calibrations to the WHO standard.

Eradication of hepatitis C virus in patients successfully treated for chronic hepatitis C

BACKGROUND & AIMS

It is unclear whether hepatitis C virus (HCV) is eradicated in patients with chronic hepatitis C who achieved a sustained virologic response (SVR).

METHODS

In this long-term follow-up study, including chronic hepatitis C patients who achieved SVR after interferon-based therapy, the presence of residual HCV RNA in serum, liver, and peripheral blood mononuclear cells (PBMCs) was assessed, using transcription-mediated amplification (sensitivity, <9.6 IU/mL). The benefit of SVR on liver fibrosis was evaluated using the METAVIR score.

RESULTS

A total of 344 patients were followed up for a median duration of 3.27 years (range, 0.50-18 y; interquartile range [IQR], 1.68-5.35 y). A total of 114 patients had a posttreatment liver tissue (median, 0.50 y; range, 0-14 y; IQR, 0-3.5 y) and a total of 156 had one PBMC (median, 3.0 y; range, 0.50-18 y; IQR, 1.25-5.50 y). Serum HCV RNA remained undetectable (1300 samples), indicating that none of the patients had a relapse. HCV RNA was detectable in 2 of 114 (1.7%) liver specimens, and in none of 156 PBMC specimens. Histologic analysis of 126 paired pretreatment and posttreatment liver biopsy specimens (median, 0.50 y; range, 0-14 y; IQR, 0-3.5 y) showed that fibrosis stage was improved in 56%, stable in 32%, deteriorated in 12%. Regression of cirrhosis was observed in 9 of 14 (64%) (95% confidence interval, 39-89) patients. No cirrhosis decompensation was observed, and 3 patients developed hepatocellular carcinoma.

CONCLUSIONS

In this large cohort of chronic hepatitis C patients, SVR was durable up to 18 years after treatment cessation, in addition to fibrosis stability/improvement (88%) and cirrhosis regression (64%). The presence of residual HCV RNA was observed only in liver tissue (1.7%). This result strongly suggests that SVR may be considered to show eradication of HCV infection.

Tailored treatment for hepatitis C

Considering the high number of global cases of hepatitis C virus (HCV) infection (around 175 million), effective, individualized, tailored treatment approaches are imperative. In this respect, defining patients according to their initial response profiles was shown to have great impact on choosing the optimal treatment duration. The application of new more sensitive HCV RNA tests may further help to improve treatment individualization. In spite of the many relevant studies conducted in the past and at present, however, this problem is far from being resolved. Generally, it can be said that the presence of a rapid virologic response is a significant predictor of favorable outcome and permits an abbreviated treatment period. In contrast, patients who have a slow response have a high risk for relapse but seem to profit from extending treatment duration. This viral kinetically driven approach to tailor treatment is generally applicable to all genotypes.

Clearance of hepatitis C virus RNA from the peripheral blood mononuclear cells of blood donors who spontaneously or therapeutically control their plasma viremia

We determined whether hepatitis C virus (HCV) RNA could be detected associated with peripheral blood mononuclear cells (PBMC) of seropositive blood donors who had spontaneously or therapeutically cleared their plasma viremia. Blood donor plasma viremia status was first determined with a highly sensitive transcription-mediated amplification (TMA) test performed in duplicate assays. PBMC from 69 aviremic and 56 viremic blood donors were then analyzed for the presence of HCV RNA with TMA adapted to detect viral RNA in PBMC and with a reverse transcription-nested polymerase chain reaction assay. PBMC-associated HCV RNA was detected in none of the 69 aviremic donors, including all 6 subjects with a sustained viral response following antiviral therapy. PBMC-associated HCV RNA was detected in 43 of the 56 viremic donors. The 13 viremic donors with no detectable PBMC-associated HCV RNA all had very low viral loads (6 positive only in 1 of 2 duplicate plasma TMA assays, 6 with viral loads below 100 HCV RNA copies/mL, and 1 with a viremia of 2700 HCV RNA copies/mL). The absence of detectable PBMC HCV RNA detection in all 69 aviremic donors reported here contrasts with prior studies, possibly as a result of the higher sensitivity of the TMA assay used to test for plasma viremia.

CONCLUSION

Our results indicate that PBMC are unlikely to serve as a long-lived reservoir of HCV in aviremic subjects.

Prognostic significance of hepatitis C virus RNA detection by transcription-mediated amplification with negative polymerase chain reaction during therapy with peginterferon alpha and ribavirin

The lower limit of detection of most polymerase chain reaction (PCR) assays for hepatitis C virus (HCV) RNA is 50 IU/ml, compared to 5 IU/ml for the transcription-mediated amplification (TMA) method. We retrospectively reviewed 57 patients to assess the predictive value of a positive TMA in the setting of a negative PCR during antiviral therapy. Patients were divided into (1) PCR-/TMA+ (discordant; n=21) and (2) PCR-/TMA-(concordant; n=36). Sustained virologic response (SVR) was decreased in the discordant group (48% vs. 75%; P=0.04). In discordant patients, SVR was more frequent in patients who had one positive TMA than in those who had two or more positive TMAs or one positive TMA and recurrent HCV RNA detectability by PCR during treatment (78% vs. 25%; P=0.03). Breakthrough occurred more frequently in discordant patients (24% vs. 3%; P=0.02). A positive TMA on two or more occasions in patients who have become PCR-negative on therapy indicates a high likelihood of treatment failure.

Optimization of the virus concentration method using polyethyleneimine-conjugated magnetic beads and its application to the detection of human hepatitis A, B and C viruses

To enhance the sensitivity of virus detection by polymerase chain reaction (PCR) and reverse transcription PCR (RT-PCR), a novel virus concentration method using polyethyleneimine (PEI)-conjugated magnetic beads was developed in our previous study. However, several viruses could not be concentrated by this method. In this paper, the conditions of virus concentration were optimized to concentrate a wide range of viruses more efficiently. The PEI beads adsorbed viruses more efficiently than other cationic polymers, and the optimum virus concentration was obtained under weak acidic conditions. Mass spectrometric analysis revealed that several serum proteins, such as complement type 3, complement type 4 and immunoglobulin M (IgM), were co-adsorbed by the PEI beads, suggesting that the beads may adsorb viruses not only by direct adsorption, but also via immune complex formation. This hypothesis was confirmed by the result that poliovirus, which PEI beads could not adsorb directly, could be concentrated by the beads via immune complex formation. On the other hand, hepatitis A (HAV) and hepatitis C (HCV) viruses were adsorbed directly by PEI beads almost completely. Like poliovirus, hepatitis B virus (HBV) was concentrated efficiently by the addition of anti-HBV IgM. In conclusion, virus concentration using PEI beads is a useful method to concentrate a wide range of viruses and can be used to enhance the sensitivity of detection of HAV, HBV and HCV.

Current therapy for hepatitis C

INTRODUCTION

Pegylated interferon alfa in combination with ribavirin has been established as standard therapy for chronic hepatitis C virus (HCV) infection with sustained virologic response rates of 54-63%. The duration of therapy depends on the HCV genotype with currently 48 weeks for genotype 1 and 24 weeks for genotypes 2 and 3.

RESULTS AND DISCUSSION

The probability of sustained virologic response is very low (<1-2%) in genotype-1-infected patients without a 2-log decline of HCV RNA concentration after 12 weeks of therapy, and treatment can therefore be discontinued early.

CONCLUSION

Efficient treatment of the multiple side-effects of interferon-based antiviral therapy is essential in order to improve compliance, prevent dose reduction or early discontinuation and therefore enhance the probability of sustained response. Future developments of interferon-based therapy aim at the individualisation of the duration of therapy according to the kinetics of viral reduction. Furthermore, direct antiviral drugs, which are currently under investigation in phase I/II clinical trials, will fundamentally expand the treatment options of HCV infection in the next few years.

Hepatitis C inflection in dialysis patients: a link to poor clinical outcome?

Among the 350,000 maintenance dialysis patients in the USA, the mortality rate is high (20-23% per year) as is the prevalence of hepatitis C virus (HCV) infection (5-15%). An additional same number of dialysis patients in the USA may be infected with HCV but have undetectable HCV antibodies. Almost half of all deaths in dialysis patients, including HCV-infected patients, are due to cardiovascular disease. Since over two-thirds of dialysis patients die within 5 years of initiating dialysis and because markers of malnutrition-inflammation complex syndrome (MICS), rather than traditional cardiovascular risk factors, are among the strongest predictors of early death in these patients, the impact of HCV infection on nutritional status and inflammation may be a main cause of poor survival in this population. Based on data from our cross-sectional and limited longitudinal studies, we hypothesize that HCV infection confounds the association between MICS and clinical outcomes in dialysis patients and, by doing so, leads to higher short-term cardiovascular events and death. Understanding the natural history of HCV and its association with inflammation, nutrition and outcomes in dialysis patients may lead to testing more effective anti-HCV management strategies in this and other similar patient populations, providing benefits not only for HCV infection but the detrimental consequences associated with this infection. In this article, we review the link between the HCV infection and mortality in dialysis patients and compare HCV antibody to molecular methods to detect HCV infection in these individuals.

HCV RNA detection by TMA during the hepatitis C antiviral long-term treatment against cirrhosis (Halt-C) trial

For making treatment decisions related to chronic hepatitis C, the utility of HCV RNA tests with increased sensitivity has not been defined. Prior interferon nonresponders with advanced fibrosis (n = 1,145) were retreated with peginterferon alpha-2a and ribavirin. Patients who were HCV RNA-negative by a polymerase chain reaction (PCR)-based assay (Roche COBAS Amplicor HCV Test, v. 2.0; lower limit of detection [LOD] 100 IU/mL) at week 20 (W20) received treatment for 48 weeks. Stored specimens were tested using the Bayer VERSANT HCV RNA Qualitative (TMA) Assay (LOD 9.6 IU/mL) and compared to PCR results for the ability to predict sustained virological response (SVR; defined as undetectable HCV RNA by PCR at W72). Nearly all PCR-positive samples (1006/1007, 99.9%) were positive as assessed by TMA. Among 1,294 PCR-negative samples, 22% were TMA-positive. Negative TMA results were more predictive of SVR than were negative PCR results at W12 (82% vs. 64%, P < .001) and at W20 (66% vs. 52%, P = 0.001). SVR was more likely the earlier TMA had become negative during treatment (82% at W12, 44% at W20, 20% at W24). Among 45 patients who were TMA-positive but were PCR-negative at W20 and W24, none achieved SVR (95% CI: 0%-8%). Approximately 10% of patients with a single positive TMA result at the end of treatment still achieved SVR. In conclusion, negative TMA results at or after W12 were superior to negative PCR results for predicting SVR. In patients with negative PCR results during treatment, a single positive TMA test did not exclude SVR, although persistently positive tests did.

Prevalence of hepatitis C virus (HCV) infection and HCV genotypes of hemodialysis patients in Salvador, Northeastern Brazil

Hepatitis C virus (HCV) infection has been identified as the major cause of chronic liver disease among patients on chronic hemodialysis (HD), despite the important reduction in risks obtained by testing candidate blood donors for anti-HCV antibodies and the use of recombinant erythropoietin to treat anemia. A cross-sectional study was performed to estimate the prevalence of HCV infection and genotypes among HD patients in Salvador, Northeastern Brazil. Anti-HCV seroprevalence was determined by ELISA in 1243 HD patients from all ten different dialysis centers of the city. HCV infection was confirmed by RT-PCR and genotyping was performed by restriction fragment length polymorphism. Anti-HCV seroprevalence among HD patients was 10.5% (95% CI: 8.8-12.3) (Murex anti-HCV, Abbott Murex, Chicago, IL, USA). Blood samples for qualitative HCV detection and genotyping were collected from 125/130 seropositive HD patients (96.2%). HCV-RNA was detected in 92/125 (73.6%) of the anti-HCV-positive patients. HCV genotype 1 (77.9%) was the most prevalent, followed by genotype 3 (10.5%) and genotype 2 (4.6%). Mixed infections of genotypes 1 and 3 were found in 7.0% of the total number of patients. The present results indicate a significant decrease in anti-HCV prevalence from 23.8% detected in a study carried out in 1994 to 10.5% in the present study. The HCV genotype distribution was closely similar to that observed in other hemodialysis populations in Brazil, in local candidate blood donors and in other groups at risk of transfusion-transmitted infection.

Treatment of Relapsers after Combination Therapy for Chronic Hepatitis C

Sustained virologic response rates are significantly higher in patients who have relapsed after a previous course of therapy compared with patients who did not respond. A meta-analysis of combination therapy in patients who failed IFN monotherapy reported SVR rates of 52% in relapsers to prior therapy and 16% in nonresponders. Similarly, relapsers after combination standard IFN and RBV therapy have higher SVR rates than combination of therapy nonresponders when treated with pegylated interferon and ribavirin. For this reason, patients who relapse after a previous course of therapy should be considered potential candidates for retreatment. Factors that have been associated with SVR in these patients include genotype non-I, low viral loads, and lesser degrees of fibrosis. The course of treatment in all patients who have relapsed after prior therapy should be reviewed to identify possible reasons for failure to achieve an SVR. In particular, optimal dosing of PEG IFN and RBV and the occurrence and timing of treatment dose reductions during prior therapy should be reviewed. The reasons for dose reduction should be addressed before initiating another course of therapy in an effort to optimize the chance for a SVR. Patients who had dose reduction for depression, anemia, or neutropenia, should be considered for antidepressants, erythropoietin, or, if neutropenia is severe, granulocyte colony stimulating factor therapy, respectively, during retreatment. Prolongation of therapy beyond 48 weeks in patients with relapse after a standard course of PEG IFN and RBV may offer a chance of SVR. Novel agents currently in development, including protease and polymerase inhibitors, may prove to be therapeutic options for these patients in the future.

Prevalence of hepatitis C virus infection and HCV genotypes among hemophiliacs in the State of Bahia, Northeastern Brazil: analysis of serological and virological parameters

The objective of the present study was to analyze HCV serological and virological parameters from hemophiliacs in the State of Bahia. Anti-HCV was investigated by ELISA in a cohort of 268 hemophiliacs A/B who were followed-up in a reference unit for hemotherapy in the State of Bahia. HCV viremia and genotypes were also determined from a subset of 66 anti-HCV seropositive hemophiliacs. Seroprevalence among hemophiliacs was 42.2% (95% CI 36.5-48.1) and was significantly higher (p<0.05) according to age > or =10 years, presence of factor VIII/IX inhibitory antibodies and other infection markers. None of the hemophiliacs less than 5 years of age were anti-HCV seropositive. Viremia was detectable in 77.3% (51/66). HCV genotype 1 (74%) was the most prevalent followed by genotype 3 (22%) and genotype 2 (4%). Our results indicate that HCV prevalence is still high among hemophiliacs, although HCV transmission was not observed in young hemophiliacs.

Clinical Performance of the New Roche Cobas® Taqman HCV Test and High Pure System for Extraction, Detection and Quantitation of HCV RNA in Plasma and Serum

We evaluated the Roche COBAS® TaqMan HCV Test For Use With The High Pure System (TaqMan HPS; Roche Diagnostics), for the extraction, detection and quantitation of hepatitis C virus (HCV) RNA in serum or plasma of HCV-infected individuals. The TaqMan HPS is a real-time PCR assay with a reported linear dynamic range of 3.0x101 to 2.0x108 HCV RNA IU/ml, and a reported lower limit of detection (LLD) of 10 IU/ml. Calculation of the HCV RNA titre is based upon an external standard curve in the presence of an internal control. Intra-assay and inter-assay variation were small in reference panel members with HCV RNA ≥100 IU/ml. Genotype performance and quantitative correlation between the TaqMan HPS and the bDNA (VERSANT® HCV 3.0 assay; Bayer Diagnostics), assessed in 59 patient samples, were good for HCV genotype 1 but poor for genotypes 2, 3 and 4. For genotypes 2, 3 and 4, values obtained from the TaqMan HPS were in general 0.5 log lower than those from the bDNA. Sensitivity was poor in low viral titre samples of genotypes 1, 2, 3 and 4. The LLD (95%) was estimated at 41 HCV RNA IU/ml for genotype 4. The TaqMan HPS underestimates HCV RNA at all levels in plasma and serum from HCV-infected individuals, and the LLD should be reconsidered. This is clinically relevant because underestimation of HCV RNA levels during therapy may lead physicians into making incorrect treatment decisions.

Hepatitis C minimal residual viremia (MRV) detected by TMA at the end of Peg-IFN plus ribavirin therapy predicts post-treatment relapse

BACKGROUND/AIMS

Around 15-25% of chronic hepatitis C patients treated with Peg-IFN plus ribavirin become HCV-RNA negative by PCR during therapy but relapse after its withdrawal. We investigated whether minimal residual viremia (MRV) might be detected in these cases by Transcription-Mediated Amplification (TMA).

METHODS

Two hundred and ninety-two consecutive patients (143 HCV-1, 82 HCV-2, 56 HCV-3 and 11 HCV-4) were prospectively treated with a standard schedule of Peg-IFNalpha 2b plus ribavirin combination and end-of-therapy response was assessed by conventional PCR using 2 protocol serum samples obtained 6-8h before the last two scheduled weekly injections of Peg-IFN. PCR negative samples were re-tested by TMA and the results were then correlated with the virological outcome after therapy withdrawal.

RESULTS

Among 208 patients who were repeatedly HCV-RNA negative by PCR at the end-of-therapy, 26 (12.5%) were found HCV-RNA positive by TMA. Twenty-two of them, (96%) were PCR-relapsers after therapy withdrawal, compared to only 14% of the 182 TMA negative patients (P<0.0001). This virological profile was more frequent in HCV-1 and HCV-3 infected patients and correlated with a slower virological response during therapy.

CONCLUSIONS

At the end of Peg-IFN plus ribavirin therapy, TMA is superior to PCR in identifying patients with sustained HCV-RNA clearance.