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

Internet-guided HCV-RNA testing: A promising tool to achieve hepatitis C micro-elimination among men who have sex with men

In the Netherlands, hepatitis C virus (HCV) transmission occurs primarily in men who have sex with men (MSM). By early diagnosis and immediate treatment of acute HCV infections, HCV micro-elimination in MSM is within reach. In cooperation with the community affected, we developed an online HCV-RNA home-based self-sampling test service. This service combined online HCV self-risk assessment with the possibility to test anonymously for HCV-RNA. The service was available in the Netherlands from February 2018 till December 2020 and was promoted online on various dating sites and offline by community volunteers. Using website user data, test results and an online post-test user survey, we evaluated the service and user experiences. The website page with information about testing was visited by 3401 unique users, of whom 2250 used the HCV-risk assessment tool, 152 individuals purchased 194 HCV-RNA tests, and 104 tests were used, of which 101 gave a conclusive result. The target population of MSM at risk was successfully reached with 44.1% of users receiving the advice to test. The test service had a satisfactory uptake (6.8%, 152/2250), a very high HCV-RNA positivity rate (10.9%, 11/101) and was considered acceptable and easy to use by most MSM. We demonstrate that an HCV-RNA home-based self-sampling test service is successful in diagnosing HCV infections among MSM. This service could be a valuable addition to existing sexual healthcare services as it may reach men who are otherwise not tested.

Genosensors as an alternative diagnostic sensing approaches for specific detection of various certain viruses: a review of common techniques and outcomes

Viral infections are responsible for the deaths of millions of people throughout the world. Since outbreak of highly contagious and mutant viruses such as contemporary sars-cov-2 pandemic, has challenged the conventional diagnostic methods, the entity of a thoroughly sensitive, specific, rapid and inexpensive detecting technique with minimum level of false-positivity or -negativity, is desperately needed more than any time in the past decades. Biosensors as minimized devices could detect viruses in simple formats. So far, various nucleic acid, immune- and protein-based biosensors were designed and tested for recognizing the genome, antigen, or protein level of viruses, respectively; however, nucleic acid-based sensing techniques, which is the foundation of constructing genosensors, are preferred not only because of their ultra-sensitivity and applicability in the early stages of infections but also for their ability to differentiate various strains of the same virus. To date, the review articles related to genosensors are just confined to particular pathogenic diseases; In this regard, the present review covers comprehensive information of the research progress of the electrochemical, optical, and surface plasmon resonance (SPR) genosensors that applied for human viruses' diseases detection and also provides a well description of viruses' clinical importance, the conventional diagnosis approaches of viruses and their disadvantages. This review would address the limitations in the current developments as well as the future challenges involved in the successful construction of sensing approaches with the functionalized nanomaterials and also allow exploring into core-research works regarding this area.

Envelope-Specific IgG3 and IgG1 Responses Are Associated with Clearance of Acute Hepatitis C Virus Infection

Hepatitis C virus (HCV) can be cleared naturally in a subset of individuals. However, the asymptomatic nature of acute HCV infection makes the study of the early immune response and defining the correlates of protection challenging. Despite this, there is now strong evidence implicating the humoral immune response, specifically neutralising antibodies, in determining the clearance or chronicity outcomes of primary HCV infection. In general, immunoglobulin G (IgG) plays the major role in viral neutralisation. However, there are limited investigations of anti-HCV envelope protein 2 (E2) isotypes (IgM, IgG, IgA) and IgG subclasses (IgG1-4) in early HCV infection. In this study, using a rare cohort of 14 very recently HCV-infected individuals (4-45 days) with varying disease outcome (n = 7 clearers), the timing and potency of anti-HCV E2 isotypes and IgG subclasses were examined longitudinally, in relation to neutralising antibody activity. Clearance was associated with anti-E2 IgG, specifically IgG1 and IgG3, and appeared essential to prevent the emergence of new HCV variants and the chronic infection outcome. Interestingly, these IgG responses were accompanied by IgM antibodies and were associated with neutralising antibody activity in the subjects who cleared infection. These findings provide novel insights into the early humoral immune response characteristics associated with HCV disease outcome.

Paper-based point-of-care test with xeno nucleic acid probes

Bridging the unmet need of efficient point-of-care testing (POCT) in biomedical engineering research and practice with the emerging development in artificial synthetic xeno nucleic acids (XNAs), this review summarized the recent development in paper-based POCT using XNAs as sensing probes. Alongside the signal transducing mode and immobilization methods of XNA probes, a detailed evaluation of probe performance was disclosed. With these new aspects, both researchers in synthetic chemistry / biomedical engineering and physicians in clinical practice could gain new insights in designing, manufacturing and choosing suitable reagents and techniques for POCT.

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

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

Clearance of hepatitis C virus is associated with early and potent but narrowly-directed, Envelope-specific antibodies

Hepatitis C virus (HCV) is one of very few viruses that are either naturally cleared, or alternatively persist to cause chronic disease. Viral diversity and escape, as well as host adaptive immune factors, are believed to control the outcome. To date, there is limited understanding of the critical, early host-pathogen interactions. The asymptomatic nature of early HCV infection generally prevents identification of the transmitted/founder (T/F) virus, and thus the study of host responses directed against the autologous T/F strain. In this study, 14 rare subjects identified from very early in infection (4–45 days) with varied disease outcomes (n = 7 clearers) were examined in regard to the timing, breadth, and magnitude of the neutralizing antibody (nAb) response, as well as evolution of the T/F strain. Clearance was associated with earlier onset and more potent nAb responses appearing at a mean of 71 days post-infection (DPI), but these responses were narrowly directed against the autologous T/F virus or closely related variants. In contrast, a delayed onset of nAbs (mean 425 DPI) was observed in chronic progressors that appear to have targeted longitudinal variants rather than the T/F strain. The nAb responses in the chronic progressors mapped to known CD81 binding epitopes, and were associated with rapid emergence of new viral variants with reduced CD81 binding. We propose that the prolonged period of viremia in the absence of nAbs in these subjects was associated with an increase in viral diversity, affording the virus greater options to escape nAb pressure once it emerged. These findings indicate that timing of the nAb response is essential for clearance. Further investigation of the specificities of the early nAbs and the factors regulating early induction of protective nAbs is needed.

Magnetic bead/capture DNA/glucose-loaded nanoliposomes for amplifying the glucometer signal in the rapid screening of hepatitis C virus RNA

A digital detection strategy based on a portable personal glucometer (PGM) was developed for the simple, rapid, and sensitive detection of hepatitis C virus (HCV) RNA, involving the release of glucose-loaded nanoliposomes due to coupling-site-specific cleavage by the endonuclease BamHI. The glucose-loaded nanoliposomes were synthesized using a reversed-phase evaporation method and provided an amplified signal at the PGM in the presence of HCV RNA. Initially, a 21-mer oligonucleotide complementary to HCV RNA was covalently conjugated to a magnetic bead through the amino group at the 5' end of the oligonucleotide, and then bound to a glucose-loaded liposome by typical carbodiimide coupling at its 3' end. In the presence of the target HCV RNA, the target hybridized with the oligonucleotide to form double-stranded DNA. The symmetrical duplex sequence 5'-GGATCC-3' between guanines was then catalytically cleaved by BamHI, which detached the glucose-loaded liposome from the magnetic bead. Following magnetic separation of the bead, the detached glucose-loaded liposome was lysed using Triton X-100 to release the glucose molecules within it, which were then detected as an amplified signal at the digital PGM. Under optimal conditions, the PGM signal increased with increasing HCV RNA, and displayed a strongly linear dependence on the level of HCV RNA for concentrations ranging from 10 pM to 1.0 μM. The detection limit (LOD) of the system was 1.9 pM. Good reproducibility and favorable specificity were achieved in the analysis of the target HCV RNA. Human serum samples containing HCV RNA were analyzed using this strategy, and the developed sensing platform was observed to yield satisfactory results based on a comparison with the corresponding results from a Cobas^® Amplicor HCV Test Analyzer. Graphical abstract A digital detection strategy utilizing a personal glucometer was developed for the detection of hepatitis C virus RNA. The strategy involved the use of the endonuclease BamHI along with a 21-mer oligonucleotide conjugated to both a magnetic bead and a glucose-loaded nanoliposome. Hybridization of the nucleotide with the target RNA triggered the coupling-site-specific cleavage of the duplex by BamHI, leading to the release of the glucose-loaded nanoliposome. Following separation of the magnetic bead, the free nanoliposome was dissolved, liberating the glucose molecules within it, which in turn were detected as an amplified signal by the glucometer.

Rapid and sensitive detection of viral nucleic acids using silicon microchips

Rapid and sensitive amplification of viral nucleic acids is feasible on a flexible silicon microchip technology platform.

Performance evaluation of the Aptima® HCV Quant Dx assay for hepatitis C virus (HCV) RNA detection and quantification in comparison to the Abbott RealTime HCV assay

BACKGROUND

The Aptima HCV Quant Dx assay (Aptima) is a real-time transcription-mediated amplification assay CE-approved for the diagnosis and monitoring of hepatitis C virus (HCV) infection.

OBJECTIVE

Aptima's analytical performance was compared to the Abbott RealTime HCV assay (RealTime) in a clinical routine setting.

STUDY DESIGN

Overall 295 clinical plasma samples (117 prospective/fresh; 178 retrospective/frozen) from HCV-infected patients were tested in Aptima and RealTime to determine concordance on qualitative and quantitative results. Linearity and precision at low viral loads (VLs; 0.8-3.3LogIU/mL) was tested using dilutions of the 5th WHO standard, in 10 and 20 replicates in the two assays, respectively. The ability to measure different HCV genotypes and accuracy were analyzed using the Seracare EQA panel.

RESULTS

Inter-assay agreement for qualitative results (prospective samples) was 88% (kappa=0.78). For the 127 samples with quantitative results in both assays, Aptima yielded on average slightly higher values (by 0.24LogIU/mL; Bland-Altman method) than RealTime. Concordance between assay results was excellent (R=0.98). At low VLs (0.8-3.3LogIU/mL), Aptima demonstrated good linearity and precision, similar to RealTime. Aptima detected and accurately quantified all main HCV genotypes.

CONCLUSIONS

Aptima demonstrated excellent precision, linearity, and accuracy in all genotypes tested. Good concordance was observed between Aptima and RealTime assays in clinical samples. The performance of the Aptima assay, on the fully automated Panther platform, makes it an excellent candidate for the detection and monitoring of HCV RNA in plasma and serum samples.

HCV management in resource-constrained countries

With the arrival of all-oral directly acting antiviral (DAA) therapy with high cure rates, the promise of hepatitis C virus (HCV) eradication is within closer reach. The availability of generic DAAs has improved access to countries with constrained resources. However, therapy is only one component of the HCV care continuum, which is the framework for HCV management from identifying patients to cure. The large number of undiagnosed HCV cases is the biggest concern, and strategies to address this are needed, as risk factor screening is suboptimal, detecting <20% of known cases. Improvements in HCV confirmation through either reflex HCV RNA screening or ideally a sensitive point of care test are needed. HCV notification (e.g., Australia) may improve diagnosis (proportion of HCV diagnosed is 75%) and may lead to benefits by increasing linkage to care, therapy and cure. Evaluations for cirrhosis using non-invasive markers are best done with a biological panel, but they are only moderately accurate. In resource-constrained settings, only generic HCV medications are available, and a combination of sofosbuvir, ribavirin, ledipasvir or daclatasvir provides sufficient efficacy for all genotypes, but this is likely to be replaced with pangenetypic regimens such as sofosbuvir/velpatasvir and glecaprevir/pibrentaasvir. In conclusion, HCV management in resource-constrained settings is challenging on multiple fronts because of the lack of infrastructure, facilities, trained manpower and equipment. However, it is still possible to make a significant impact towards HCV eradication through a concerted effort by individuals and national organisations with domain expertise in this area.

Convergent evolution of twintron-like configurations: One is never enough

Introns inserted within introns are commonly referred to as twintrons, however the original definition for twintron implied that splicing of the external member of the twintron could only proceed upon splicing of the internal member. This review examines the various types of twintron-like arrangements that have been reported and assigns them to either nested or twintron categories that are subdivided further into subtypes based on differences of their mode of splicing. Twintron-like arrangements evolved independently by fortuitous events among different types of introns but once formed they offer opportunities for the evolution of new regulatory strategies and/or novel genetic elements.

Molecular epidemiological analysis of three hepatitis C virus outbreaks in Jammu and Kashmir State, India

Outbreaks of hepatitis C virus (HCV) infection are associated with unsafe injection practices, intravenous drug abuse and other exposure to blood and body fluids. We report here three outbreaks of HCV infection from Jammu and Kashmir (J&K) State, India, which occurred over a period of 3 years and in which molecular epidemiological investigations identified a presumptive common source of infection, most likely a single healthcare venue. Representative blood samples collected from cases of hepatitis C were sent to the National Centre for Disease Control (NCDC) for molecular characterization. These samples were positive by HCV ELISA. Subsequently, specimens were also tested for the presence of HCV RNA by RT-PCR. Sequencing was carried out for all positive samples. A total of 812 cases were laboratory confirmed by HCV ELISA; a total of 115 samples were sent to the NCDC for RT-PCR, and 77 were positive. Subtype 3a of HCV was found in all samples from Anantnag (February 2013); and for subtype 3b, in all samples from Srinagar (May 2015). Subtypes 3a and 3g were identified from two samples from the Kulgam outbreak (July 2014). A detailed epidemiological investigation should be conducted whenever a cluster of HCV cases is revealed, as this potentially allows for the identification of larger outbreaks. Epidemiological investigations of outbreaks should be further supported by inclusion of molecular tests. Efforts to limit therapeutic injections to only those cases having strong medical/surgical indications and to restrict the use of non-sterile needles are essential to prevent transmission of HCV.

Incident Hepatitis C Virus Genotype Distribution and Multiple Infection in Australian Prisons

Hepatitis C virus (HCV) is a highly diverse pathogen that is classified into seven distinct genotypes. Simultaneous or sequential reinfection with multiple HCV genotypes is recognized in high-risk populations, such as injecting drug users (IDUs). Multiple infection is of clinical concern as different genotypes have various sensitivities to current antiviral therapies. Therefore, a better understanding of the frequency of multiple infection and of the genotypes currently being transmitted is clinically relevant. An Australian cohort of IDUs (n = 123), identified with primary incident infection, was followed for multiple infection by regular HCV RNA testing between 2005 and 2013. A total of 354 samples were tested. Sequencing of primary incident infections revealed that genotype 3a was the most common circulating genotype, followed by genotype 1a. Examination of longitudinally collected samples identified complex patterns of multiple infection, including reinfection and superinfection. In those with multiple infection, there was no apparent evidence of homotypic immunity conferring protection against reinfection of the same subtype. This study revealed frequent multiple infection in a high-risk prisoner cohort, illustrating the complex nature of HCV infection and reinfection and highlighting the need for pan-genotypic antiviral therapies.

Hepatitis C Virus Genotype and Subtype Distribution in Patient Specimens Tested at the University of Texas Medical Branch, Galveston, Between January 2011 and November 2014

Hepatitis C virus (HCV) genotype/subtype data are routinely generated in clinical laboratories to guide treatment. Genotype data can also inform genotype distribution and molecular epidemiology of HCV infections in patient populations and geographical regions that clinics/laboratories serve. The aim of this study was to determine the distribution of HCV genotypes/subtypes and their association with demographic characteristics among the patients that were routinely tested in the Molecular Diagnostics Laboratory at The University of Texas Medical Branch (UTMB) at Galveston. Among the 6573 patients tested between January 2011 and November 2014, the most frequent HCV genotype/subtype was 1a (65.3%), followed by 3a (11.5%), 1b (10.4%), and 2b (8.8%). Combined, genotype 4 and genotype 6 were found in less than 1% of this cohort. Approximately 1.3% of the patients presented multiple genotypes/subtypes. Factors independently associated with genotypes and subtypes were race/ethnicity, sex, and patient age.

Real-Time PCR Assays for the Quantification of HCV RNA: Concordance, Discrepancies and Implications for Response Guided Therapy

BACKGROUND AND AIMS

Monitoring of chronic Hepatitis C (CHC) treatment relies on HCV RNA quantification by means of real-time PCR methods. Assay specific analytical sensitivities may impact therapy management.

METHODS

Comparative analysis between three commercial assays (Roche COBAS AmpliPrep/COBAS TaqMan Version 1 (CAP/CTM Ver. 1), Version 2 (CAP/CTM Ver. 2) and the Abbott RealTime HCV (ART) assay) was performed on 247 available samples taken at key decision time points during antiviral therapy of 105 genotype 1 patients (triple therapy: n = 70; dual therapy: n = 35).

RESULTS

Overall concordance of HCV RNA measurements was high between the two Roche systems (89%; n = 220/247) but lower between the Roche assays and the ART (CAP/CTM Ver. 1 vs ART: 77.3%; n = 191/247 and CAP/CTM v.2 vs ART: 80.1%; n = 198/247). Most discrepancies were noted in week 4/8 samples with residual viremia (

CONCLUSION

An abbreviated course of treatment can safely be applied in patients with residual viremia ( Collapse

Key Words Collapse

MESH Headings

• Female
• Hepatitis C, Chronic/blood
• Hepatitis C, Chronic/drug therapy
• Humans
• Male
• Monitoring, Physiologic/instrumentation
• Monitoring, Physiologic/methods
• RNA, Viral/blood
• Real-Time Polymerase Chain Reaction/instrumentation
• Real-Time Polymerase Chain Reaction/methods

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Grants Collapse

Affiliation(s)

Robert Strassl Department of Laboratory Medicine, Division of Clinical Virology, Medical University of Vienna, Vienna, Austria
Karoline Rutter Department of Internal Medicine III, Division of Gastroenterology & Hepatology, Medical University of Vienna, Vienna, Vienna, Austria
Albert Friedrich Stättermayer Department of Internal Medicine III, Division of Gastroenterology & Hepatology, Medical University of Vienna, Vienna, Vienna, Austria
Sandra Beinhardt Department of Internal Medicine III, Division of Gastroenterology & Hepatology, Medical University of Vienna, Vienna, Vienna, Austria
Michael Kammer Center for Medical Statistics, Informatics, and Intelligent Systems (CeMSIIS), Medical University of Vienna, Vienna, Austria
Harald Hofer Department of Internal Medicine III, Division of Gastroenterology & Hepatology, Medical University of Vienna, Vienna, Vienna, Austria
Peter Ferenci Department of Internal Medicine III, Division of Gastroenterology & Hepatology, Medical University of Vienna, Vienna, Vienna, Austria
Theresia Popow-Kraupp Department of Laboratory Medicine, Division of Clinical Virology, Medical University of Vienna, Vienna, Austria

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The prognostic value of histidine-rich glycoprotein RNA in breast tissue using unmodified gold nanoparticles assay

The aim of is this study is to explore the role of tissue histidine-rich glycoprotein (HRG) RNA as a promising clinically useful biomarker for breast cancer patients prognosis using nanogold assay. Expression of the HRG RNA was assessed by gold nanoparticles and conventional RT-PCR after purification by magnetic nanoparticles in breast tissue samples. The study included 120 patients, 60 of which were histologically proven breast carcinoma cases, 30 had benign breast lesions and 30 were healthy individuals who had undergone reductive plastic surgery. ER, PR and HER2 status were also investigated. The prognostic significance of tissue HRG RNA expression in breast cancer was explored. The magnetic nanoparticles coated with specific thiol modified oligonucleotide probe were used successfully in purification of HRG RNA from breast tissue total RNAs with satisfactory yield. The developed HRG AuNPs assay had a sensitivity and a specificity of 90 %, and a detection limit of 1.5 nmol/l. The concordance rate between the HRG AuNPs assay with RT-PCR after RNA purification using magnetic nanoparticles was 93.3 %. The median follow-up period was 60 months. Among traditional prognostic biomarkers, HRG was a significant independent prognostic marker in relapse-free survival (RFS). HRG RNA is an independent prognostic marker for breast cancer and can be detected using gold NPs assay, which is rapid, sensitive, specific, inexpensive to extend the value for breast cancer prognosis.

Evidence-based consensus on the diagnosis, prevention and management of hepatitis C virus disease

Hepatitis C virus (HCV) is a potent human pathogen and is one of the main causes of chronic hepatitis round the world. The present review describes the evidence-based consensus on the diagnosis, prevention and management of HCV disease. Various techniques, for the detection of anti-HCV immunoglobulin G immunoassays, detection of HCV RNA by identifying virus-specific molecules nucleic acid testings, recognition of core antigen for diagnosis of HCV, quantitative antigen assay, have been used to detect HCV RNA and core antigen. Advanced technologies such as nanoparticle-based diagnostic assays, loop-mediated isothermal amplification and aptamers and Ortho trak-C assay have also come to the front that provides best detection results with greater ease and specificity for detection of HCV. It is of immense importance to prevent this infection especially among the sexual partners, injecting drug users, mother-to-infant transmission of HCV, household contact, healthcare workers and people who get tattoos and piercing on their skin. Management of this infection is intended to eradicate it out of the body of patients. Management includes examining the treatment (efficacy and protection), assessment of hepatic condition before commencing therapy, controlling the parameters upon which dual and triple therapies work, monitoring the body after treatment and adjusting the co-factors. Examining the treatment in some special groups of people (HIV/HCV co-infected, hemodialysis patients, renal transplanted patients).

Understanding aggregation-based assays: nature of protein corona and number of epitopes on antigen matters

In this study, we systematically examine how the nature of the protein corona on NPs, formed from either antibody or antigen, and how the number of binding sites or epitopes on the antigen affect aggregation.

Hepatitis C virus core antigen testing in liver and kidney transplant recipients

HCV RNA levels correlate with the long-term outcome of hepatitis C in liver transplant recipients. Nucleic acid testing (NAT) is usually used to confirm HCV reinfection and to examine viral loads after liver transplantation. HCV core antigen (HCVcoreAg) testing could be an alternative to NAT with some potential advantages including very low intra- and interassay variabilities and lower costs. The performance of HCVcoreAg testing in organ transplant recipients is unknown. We prospectively studied 1011 sera for HCV RNA and HCVcoreAg in a routine real-world setting including 222 samples obtained from patients after liver or kidney transplantation. HCV RNA and HCVcoreAg test results showed a consistency of 98% with a very good correlation in transplanted patients (r > 0.85). The correlation between HCV RNA and HCVcoreAg was higher in sera with high viral loads and in samples from patients with low biochemical disease. Patients treated with tacrolimus showed a better correlation between both parameters than individuals receiving cyclosporine A. HCV RNA/HCVcoreAg ratios did not differ between transplanted and nontransplanted patients, and HCV RNA and HCVcoreAg kinetics were almost identical during the first days after liver transplantation. HCVcoreAg testing can be used to monitor HCV viral loads in patients after organ transplantation. However, the assay is not recommended to monitor antiviral therapies.

A reliable multiplex genotyping assay for HCV using a suspension bead array

The genotyping of the hepatitis C virus (HCV) plays an important role in the treatment of HCV because genotype determination has recently been incorporated into the treatment guidelines for HCV infections. Most current genotyping methods are unable to detect mixed genotypes from two or more HCV infections. We therefore developed a multiplex genotyping assay to determine HCV genotypes using a bead array. Synthetic plasmids, genotype panels and standards were used to verify the target-specific primer (TSP) design in the assay, and the results indicated that discrimination efforts using 10 TSPs in a single reaction were extremely successful. Thirty-five specimens were then tested to evaluate the assay performance, and the results were highly consistent with those of direct sequencing, supporting the reliability of the assay. Moreover, the results from samples with mixed HCV genotypes revealed that the method is capable of detecting two different genotypes within a sample. Furthermore, the specificity evaluation results suggested that the assay could correctly identify HCV in HCV/human immunodeficiency virus (HIV) co-infected patients. This genotyping platform enables the simultaneous detection and identification of more than one genotype in a same sample and is able to test 96 samples simultaneously. It could therefore provide a rapid, efficient and reliable method of determining HCV genotypes in the future.

HCV RNA quantification with different assays: implications for protease-inhibitor-based response-guided therapy

BACKGROUND

Response-guided therapy (RGT) for HCV treatment, whereby therapy duration is shortened according to on-treatment virological response, requires patient HCV RNA concentrations below the lower limit of quantification (LLOQ) or limit of detection (LOD) of the viral load assay at weeks 4 and 12. Concordance of two assays and impact on treatment decisions were investigated.

METHODS

Plasma samples (n=1,411; baseline to week 12) from HCV genotype-1-infected patients (n=290) receiving simeprevir (TMC435) plus pegylated interferon-α2a/ribavirin in the PILLAR study (NCT00882908) were analysed using Roche High-Pure-System/COBAS(®) TaqMan(®) v2.0 assay (HPS; LLOQ 25 IU/ml and LOD 15 IU/ml; Roche Diagnostics, Indianapolis, IN, USA) and reanalysed using Abbott realtime assay (ART; LLOQ and LOD 12 IU/ml; Abbott Molecular Inc., Des Plaines, IL, USA).

RESULTS

Overall, 217/766 (28.3%) samples from different time points with HCV RNA undetectable by HPS had HCV RNA detectable by ART. Conversely, 35/584 (6.0%) samples undetectable by ART were detectable by HPS. For both assays, most discrepant samples (96-100%) had HCV RNA<25 IU/ml. At week 4, 75.5% of samples were undetectable by HPS, whereas 49.4% were undetectable by ART, resulting in different RGT assessment in 26.1% (P<0.0001). At week 12, 95.4% and 91.9% of samples were undetectable with HPS and ART, respectively.

CONCLUSIONS

Lower rates of undetectable HCV RNA with ART at week 4 suggest that if RGT criteria are determined with ART, the proportion of patients qualifying for shorter treatment duration may be significantly lower (26%). Therefore, different RGT criteria may be necessary for ART to maximize numbers benefiting from shortened treatment. Further testing and validation are required.

Application of molecular diagnostic techniques for viral testing

Nucleic acid amplification techniques are commonly used currently to diagnose viral diseases and manage patients with this kind of illnesses. These techniques have had a rapid but unconventional route of development during the last 30 years, with the discovery and introduction of several assays in clinical diagnosis. The increase in the number of commercially available methods has facilitated the use of this technology in the majority of laboratories worldwide. This technology has reduced the use of some other techniques such as viral culture based methods and serological assays in the clinical virology laboratory. Moreover, nucleic acid amplification techniques are now the methods of reference and also the most useful assays for the diagnosis in several diseases. The introduction of these techniques and their automation provides new opportunities for the clinical laboratory to affect patient care. The main objectives in performing nucleic acid tests in this field are to provide timely results useful for high-quality patient care at a reasonable cost, because rapid results are associated with improvements in patients care. The use of amplification techniques such as polymerase chain reaction, real-time polymerase chain reaction or nucleic acid sequence-based amplification for virus detection, genotyping and quantification have some advantages like high sensitivity and reproducibility, as well as a broad dynamic range. This review is an up-to-date of the main nucleic acid techniques and their clinical applications, and special challenges and opportunities that these techniques currently provide for the clinical virology laboratory.

Introduction of an automated system for the diagnosis and quantification of hepatitis B and hepatitis C viruses

Hepatitis B virus (HBV) and Hepatitis C virus (HCV) infections pose major public health problems because of their prevalence worldwide. Consequently, screening for these infections is an important part of routine laboratory activity. Serological and molecular markers are key elements in diagnosis, prognosis and treatment monitoring for HBV and HCV infections. Today, automated chemiluminescence immunoassay (CLIA) analyzers are widely used for virological diagnosis, particularly in high-volume clinical laboratories. Molecular biology techniques are routinely used to detect and quantify viral genomes as well as to analyze their sequence; in order to determine their genotype and detect resistance to antiviral drugs. Real-time PCR, which provides high sensitivity and a broad dynamic range, has gradually replaced other signal and target amplification technologies for the quantification and detection of nucleic acid. The next-generation DNA sequencing techniques are still restricted to research laboratories.The serological and molecular marker methods available for HBV and HCV are discussed in this article, along with their utility and limitations for use in Chronic Hepatitis B (CHB) diagnosis and monitoring.

Laboratory diagnostics for hepatitis C virus infection

Identification of prevalent infection by hepatitis C virus (HCV) is based serologically on detecting anti-HCV immunoglobulin G, using immunoassays, immunoblot assays, and, more recently, immunochromatography-based rapid tests. None discriminate between active and resolved HCV infection. Tests for detecting HCV RNA identify active HCV infection but are costly. Serologic assays for HCV antigens have been developed and show potential for diagnosis of active HCV infection, and their performance characteristics are undergoing evaluation. The diagnosis of acute HCV infection without the demonstration of seroconversion remains elusive.

Large intervening non-coding RNA HOTAIR is associated with hepatocellular carcinoma progression

Increasing evidence suggests that large intervening non-coding RNAs (lincRNAs) regulate key pathways in cancer invasion and metastasis. In this observational retrospective study, the expression of the oncogenic lincRNA HOX transcript antisense RNA (HOTAIR) gene was measured in 63 patients with hepatocellular carcinoma (HCC) following hepatic resection. The HOTAIR gene was significantly overexpressed in HCC tissues compared with adjacent non-tumour tissues. Patients with high HOTAIR gene expression in their tumours had an increased risk of recurrence after hepatectomy. There was also a significant correlation between HOTAIR expression and lymph node metastasis. In vitro assays in the HCC cell line Bel7402 demonstrated that knockdown of HOTAIR lincRNA reduced cell proliferation and was associated with reductions in levels of matrix metalloproteinase-9 and vascular endothelial growth factor protein, which are important for cell motility and metastasis. In conclusion, HOTAIR lincRNA might be a potential biomarker for the existence of lymph node metastasis in HCC.

Performance of the Abbott RealTime and Roche Cobas TaqMan hepatitis C virus (HCV) assays for quantification of HCV genotypes

We evaluated the Abbott RealTime (ART) and Roche Cobas TaqMan Hepatitis C virus (HCV) viral load assays for quantification of HCV genotypes in patient specimens. The ART HCV assay was a more sensitive and precise tool for accurate HCV viral load quantification across the HCV genotypes tested, especially genotype 1b.

Gold nanoparticles in the clinical laboratory: principles of preparation and applications

In order to meet the challenges of effective healthcare, the clinical laboratory is constantly striving to improve testing sensitivity while reducing the required time and cost. Gold nanoparticles (AuNPs) are proposed as one of the most promising tools to meet such goals. They have unique optophysical properties which enable sensitive detection of biomarkers, and are easily amenable to modification for use in different assay formats including immunoassays and molecular assays. Additionally, their preparation is relatively simple and their detection methods are quite versatile. AuNPs are showing substantial promise for effective practical applications and commercial utilization is already underway. This article covers the principles of preparation of AuNPs and their use for development of different diagnostic platforms.

Electrochemical detection of hepatitis C virus with signal amplification using BamHI endonuclease and horseradish peroxidase-encapsulated nanogold hollow spheres

A novel electrochemical method to detect hepatitis C virus was developed based on site-specific cleavage of BamHI endonuclease and enzymatic signal amplification with horseradish peroxidase-encapsulated nanogold hollow spheres.