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

The Usefulness of Anti-HCV Signal to Cut-off Ratio in Predicting Viremia in Anti-HCV in Patients With Hepatitis C Virus Infection

Background:

Hepatitis C Virus (HCV) infection is diagnosed by antibody and RNA based methods. Patients with anti-HCV sample rate/cutoff rate (S/CO) ratios > 1 are reported as anti-HCV positive. RNA based methods are introduced to confirm positivity in seropositive samples.

Objectives:

The current study aimed to assess relationship between S/CO rates and HCV-RNA levels in the laboratory to identify HCV viremia in patients with a positive anti-HCV.

Patients and Methods:

All serum samples were assayed for anti-HCV by ELISA method. A total of 265 anti-HCV positive patients were tested for HCV-RNA testing by quantitative method using Artus HCV RG Real-time Polymerase Chain Reaction (RT- PCR) kit. Statistical analysis was done by SPSS version 16.

Results:

Of the 265 patients with HCV infection, 204 (77%) were male and the mean age was 43.53 ± 13.17 years, ranging 1 - 81 years. No correlation was found between S/CO ratios and HCV-RNA levels. There was significant difference in S/CO ratio between viremic and non-viremic subjects. The sensitivity, specificity, negative predictive value, and positive predictive value were 100%, 81.4%, 100%, and 77.2%, respectively in the S/CO ratio of 2.7.

Conclusions:

The present study indicated that anti-HCV S/Co ratio is useful to predict non-viremic patients. A cut-off value of 2.7 can determine the usefulness of HCV-RNA testing. Patients with S/CO < 2.7 are not viremic; therefore, HCV-RNA testing is not recommended. It is suggested that laboratories report S/CO ratio along with anti-HCV results to manage HCV infection better, especially in countries that quantitative HCV testing is expensive or not available.

Thin-film technology for direct visual detection of nucleic acid sequences: applications in clinical research

Certain optical conditions permit the unaided eye to detect thickness changes on surfaces on the order of 20 A, which are of similar dimensions to monomolecular interactions between proteins or hybridization of complementary nucleic acid sequences. Such detection exploits specific interference of reflected white light, wherein thickness changes are perceived as surface color changes. This technology, termed thin-film detection, allows for the visualization of subattomole amounts of nucleic acid targets, even in complex clinical samples. Thin-film technology has been applied to a broad range of clinically relevant indications, including the detection of pathogenic bacterial and viral nucleic acid sequences and the discrimination of sequence variations in human genes causally related to susceptibility or severity of disease.

In situ hybridization for the detection of hepatitis C virus RNA in human liver tissue

In situ hybridization (ISH) enables visualization of specific nucleic acid in morphologically preserved cells and tissue sections. Detection of the HCV genomes in clinical specimens is useful for differential diagnosis, particularly between recurrent HCV infection and acute cellular rejection in transplant specimens. We optimized an ISH protocol that demonstrated sensitivity and specificity for detecting genomic and replicative form of HCV RNA in tissue biopsies. Digoxigenin (Dig)-labelled sense and anti-sense riboprobes were synthesized using a plasmid containing a fragment of the highly conserved HCV noncoding region as a template. The efficiency of the Dig-labelled riboprobes in detecting genomic and replicative-intermediate HCV RNA was analysed in 30 liver biopsies from patients infected or uninfected with HCV in a blinded study. A Huh7 cell line that stably replicates genome-length HCV RNA was developed to be used as a positive control. Negative control riboprobes were used in parallel to evaluate and control for background staining. The anti-sense probe detected HCV RNA in 20/21 specimens from HCV-infected liver tissues obtained from patients and in 0/9 samples from patients with non-HCV-related liver diseases, resulting in a sensitivity and specificity of 95% and 100%, respectively. HCV genomic RNA was variably distributed in tissue sections and was located primarily in the perinuclear regions in hepatocytes. Detection of HCV RNA by our optimized ISH protocol appears to be a sensitive and specific method when processing clinical specimens. It may also be revealing when exploring the pathophysiology of HCV infection by verifying the presence of viral genetic material within heptocytes and other cellular elements of diseased liver tissue. This methodology might also evaluate the response to antiviral therapies by demonstrating the absence or alteration of genetic material in clinical specimens from successfully treated patients.

Demonstration of hepatitis C virus RNA with in situ hybridization employing a locked nucleic Acid probe in humanized liver of infected chimeric mice and in needle-biopsied human liver

Background. In situ hybridization (ISH) with high sensitivity has been requested to demonstrate hepatitis C virus (HCV) RNA in formalin-fixed, paraffin-embedded (FFPE) sections of the liver. Methods. ISH employing a locked-nucleic-acid- (LNA-)modified oligonucleotide probe and biotin-free catalyzed signal amplification system (CSAII) was applied to HCV-RNA detection in the liver tissue. Nested reverse-transcription polymerase chain reaction (RT-PCR) was performed for HCV genotyping using total RNA extracted from FFPE sections. The target tissues included FFPE tissue sections of humanized livers in HCV-infected chimeric mice (HCV genotypes 1a, 1b, and 2a and noninfected) and of needle-biopsied livers from HCV-infected patients. Results. HCV-RNA was demonstrated with the ISH technique in HCV-infected liver tissues from both chimeric mice and 9 (82%) of 11 patients with HCV infection. The HCV signals were sensitive to RNase. Nested RT-PCR confirmed the genotype in 8 (73%) of 11 livers (type 1b: 6 lesions and type 2a: 2 lesions). HCV-RNA was not identified in chronic hepatitis B lesions, fatty liver, autoimmune hepatitis, and hepatocellular carcinoma. Conclusion. ISH using the LNA-modified oligonucleotide probe and CSAII was applicable to detecting HCV-RNA in routinely prepared FFPE liver specimens.

Combined effects of alcohol and hepatitis C: a secondary analysis of alcohol use biomarkers and high-risk behaviors from two medication trials for alcohol dependence

OBJECTIVES

The goal of this secondary analysis was to examine the combined effects of HCV infection and recent alcohol use on baseline biologic markers of alcohol consumption in two outpatient medication trials for alcohol dependence. In addition, the relationship between Hepatitis C virus (HCV) infection and behavioral risk factors for HCV infection in these clinical populations were examined.

METHODS

Data (n=345) from two randomized, placebo-controlled trials of naltrexone and psychosocial treatment for alcohol dependence (Study I, n=212) and comorbid alcohol and cocaine dependence (Study II, n=133) were used to examine baseline measures of HCV risk behaviors (injection drug use, needle sharing), and biomarkers of alcohol use (AST, ALT, GGT and CDT) were compared by HCV serostatus first within each study and then across studies.

RESULTS

Although groups had differing sociodemographic profiles (as indicated by race, marital status, level of education) subjects in Study I exhibited no statistically significant differences from the Study II cohort in HCV prevalence (12.7 vs. 20.0%, p=0.07), lifetime history of injection drug use (13.8 vs. 22.0%, p=0.74), lifetime history of needle sharing (9.1 vs. 18.0%, p=0.62). As such, the data from both studies were analyzed together. Regardless of drinking status, HCV infection was significantly associated with an upward shift in the baseline level of ALT, AST, and GGT (p<0.006 for all measures) and a downward shift in baseline CDT (p=0.002). When using standard laboratory cutoff values to determine clinically significant elevations, HCV seropositivity was significantly associated with elevations in ALT, AST, GGT (p<0.001), and with decreases in CDT (p=.002).

CONCLUSIONS

These data emphasize the importance of evaluating HCV infection and HCV risk behaviors at intake in medication trials for alcohol dependence and also raise questions regarding the use of cutoff scores for ALT, AST, GGT and CDT levels as biologic markers of alcohol use in subjects when HCV status is unknown.

Detection and quantification of hepatitis C virus (HCV) by MultiCode-RTx real-time PCR targeting the HCV 3' untranslated region

A prototype, real-time reverse-transcription PCR assay, based on MultiCode-RTx technology, quantifying hepatitis C virus (HCV) RNA by targeting the HCV 3' untranslated region demonstrated linearity over 7 logs, with a good correlation between the quantitative results of this assay and the results of two commercially available comparator assays for 466 clinical specimens comprising all six HCV genotypes.

Silybin treatment is associated with reduction in serum ferritin in patients with chronic hepatitis C

GOALS

The goal of this study was to examine the effect of a standardized silybin and soy phosphatidylcholine complex (IdB 1016) on serum markers of iron status.

BACKGROUND

Milk thistle and its components are widely used as an alternative therapy for liver disease because of purported antioxidant, anti-inflammatory, and iron chelating properties.

STUDY

Thirty-seven patients with chronic hepatitis C and Batts-Ludwig fibrosis stage II, III, or IV were randomized to 1 of 3 doses of IdB 1016 for 12 weeks. Serum ferritin, serum iron, total iron binding capacity, and transferrin-iron saturation were measured at baseline, during treatment, and 4 weeks thereafter. Wilcoxon signed rank tests were used to compare baseline and posttreatment values.

RESULTS

There was a significant decrease in serum ferritin from baseline to end of treatment (mean, 244 vs. 215 mug/L; median, 178 vs. 148 mug/L; P=0.0005); 78% of subjects had a decrease in serum ferritin level. There was no significant change in serum iron or transferrin-iron saturation. Multivariate logistic regression analysis in a model that included dose, age, sex, HFE genotype, history of alcohol use, and elevated baseline ferritin levels demonstrated that stage III or IV fibrosis was independently associated with decreased posttreatment serum ferritin level.

CONCLUSIONS

Treatment with IdB 1016 is associated with reduced body iron stores, especially among patients with advanced fibrosis stage.

Evaluation of the new ARCHITECT anti-HCV screening test under routine laboratory conditions

BACKGROUND

An improved test version of the Abbott ARCHITECT anti-hepatitis C virus (HCV) test became available at the end of 2005.

STUDY DESIGN

We compared the new test version with the Ortho Vitros anti-HCV test by evaluating 2034 serum samples in parallel on both systems under routine laboratory conditions. Discordant samples were tested in the Inno-LIA HCV Score assay as well as in the RIBA HCV 3.0.

RESULTS

Of the 2034 samples 140 (6.9%) yielded positive and 1856 (91.2%) negative results in both assays. We observed discordant results in 38 samples (1.9%). All discrepant samples showed a low S/CO ratio of 1.0-6.9 (mean 2.8) in the Ortho assay and of 1.3-3.0 (mean 1.96) in the ARCHITECT assay. As expected, most of them could not be confirmed by immunoblot testing. Comparison of the results of the two immunoblots (Inno-LIA and RIBA) revealed a great variability in test results.

CONCLUSIONS

This study represents the first comparative evaluation of the modified version of the Abbott ARCHITECT anti-HCV assay in comparison with the Ortho Vitros anti-HCV test. Under routine laboratory testing, we observed good overall concordance between the two assays and no evidence that one assay shows more false-reactive or negative results than the other.

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

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

Evaluating replication-defective vesicular stomatitis virus as a vaccine vehicle

We have generated replication-competent (VSV-C/E1/E2) and nonpropagating (VSVDeltaG-C/E1/E2) vesicular stomatitis virus (VSV) contiguously expressing the structural proteins of hepatitis C virus (HCV; core [C] and glycoproteins E1 and E2) and report on their immunogenicity in murine models. VSV-C/E1/E2 and VSVDeltaG-C/E1/E2 expressed high levels of HCV C, E1, and E2, which were authentically posttranslationally processed. Both VSV-expressed HCV E1-E2 glycoproteins were found to form noncovalently linked heterodimers and appeared to be correctly folded, as confirmed by coimmunoprecipitation analysis using conformationally sensitive anti-HCV-E2 monoclonal antibodies (MAbs). Intravenous or intraperitoneal immunization of BALB/c mice with VSV-C/E1/E2 or VSVDeltaG-C/E1/E2 resulted in significant and surprisingly comparable HCV core or E2 antibody responses compared to those of control mice. In addition, both virus types generated HCV C-, E1-, or E2-specific gamma interferon (IFN-gamma)-producing CD8(+) T cells, as determined by enzyme-linked immunospot (ELISPOT) analysis. Mice immunized with VSVDeltaG-C/E1/E2 were also protected against the formation of tumors expressing HCV E2 (CT26-hghE2t) and exhibited CT26-hghE2t-specific IFN-gamma-producing and E2-specific CD8(+) T-cell activity. Finally, recombinant vaccinia virus (vvHCV.S) expressing the HCV structural proteins replicated at significantly lower levels when inoculated into mice immunized with VSV-C/E1/E2 or VSVDeltaG-C/E1/E2, but not with control viruses. Our data therefore illustrate that potentially safer replication-defective VSV can be successfully engineered to express high levels of antigenically authentic HCV glycoproteins. In addition, this strategy may therefore serve in effective vaccine and immunotherapy-based approaches to the treatment of HCV-related disease.

Performance characteristics of the ARCHITECT anti-HCV assay

INTRODUCTION

The ARCHITECT Anti-HCV assay is a fully automated high throughput chemiluminescent microparticle immunoassay (CMIA) for the detection of antibodies to structural and nonstructural proteins of the hepatitis C virus (HCV). To further enhance the performance of this test, the assay was modified to improve the specificity for blood donor specimens.

METHODS

The specificity of the enhanced ARCHITECT Anti-HCV assay was evaluated by screening blood donor samples randomly collected from various German blood banks, as well as hospitalized patient samples derived from Germany and the US. Additionally, antibody sensitivity was determined on commercially available anti-HCV seroconversion panels and on a commercially available worldwide anti-HCV genotype performance panel.

RESULTS

Apparent specificity of the modified ARCHITECT Anti-HCV assay in a blood donor population consisting of 3811 specimens was 99.92%, compared to 99.76% for the current on-market assay. Additionally, antibody sensitivity was determined on commercially available anti-HCV seroconversion panels. Seroconversion sensitivity equivalent to or better than the current on-market product was observed by testing 33 seroconversion panels.

CONCLUSION

This study demonstrates that the modified version of the ARCHITECT Anti-HCV assay shows improved specificity for blood donor specimens compared to the current assay on market without compromising sensitivity. With the availability of the improved ARCHITECT Anti-HCV assay and the recent launch of the ARCHITECT HIV Ag/Ab Combo assay, the ARCHITECT system now offers a full hepatitis/retrovirus menu with excellent performance on a high throughput, random access, automated analyzer, ideally suited for blood screening and diagnostic applications.

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

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

High-throughput ribozyme-based assays for detection of viral nucleic acids

Many reports have suggested that target-activated ribozymes hold potential value as detection reagents. We show that a "half"-ribozyme ligase is activated similarly by three unstructured oligoribonucleotides representing the major sequence variants of a hepatitis C virus 5'-untranslated region (5'-UTR) target and by a structured RNA corresponding to the entire 5'-UTR. Half-ribozyme ligation product was detected both in an ELISA-like assay and in an optical immunoassay through the use of hapten-carrying substrate RNAs. Both assay formats afford a limit of detection of approximately 1 x 10(6) HCV molecules (1.6 attomol, 330 fM), a sensitivity which compares favorably to that provided by standard immunoassays. These data suggest that target-activated ribozyme systems are a viable approach for the sensitive detection of viral nucleic acids using high-throughput platforms.

Detection of hepatitis C virus RNA in formalin-fixed paraffin-embedded sections with digoxigenin-labeled cRNA probes

Although recent studies have analyzed Hepatitis C (HCV) infections in liver tissue by in situ hybridization (ISH), many of these studies have been of limited diagnostic utility because of the low copy numbers of HCV in formalin-fixed paraffin-embedded (FFPE) tissue and failure to correlate the ISH analysis with other methods of detecting HCV. Thirty six cases of liver biopsies from patients with known HCV antibody status including 20 cases of serum HCV positive and 16 cases of serum HCV negative were analyzed. All cases showed histologic features suggestion of HCV infection. Analyses of all 36 cases were done by RT-PCR combined with Southern hybridization (RT-PCR-SH) and in situ hybridization (ISH). A prolactin riboprobe was used as a negative control. Immunohistochemistry (IHC) with an antibody against HCV (Rb 246) was also used to analyze HCV viral protein in the tissues. Of the 20 serum antibody-positive cases, RT-PCR-SH detected 18 positive cases, while ISH and IHC detected 19 and 16 positive cases, respectively. Of the 16 serum antibody-negative cases, RT-PCR-SH detected 8 positive cases while ISH and IHC detected 8 and 11 positive cases, respectively. A positive ISH signal for HCV was also detected in some lymphocytes and bile ducts in the liver. These results show that ISH with a highly specific riboprobe is comparable to RT-PCR-SH for detection of HCV infection in liver tissue.

Inter-laboratory comparison of qualitative and quantitative detection of hepatitis C (HCV) virus RNA in diagnostic virology: a multicentre study (MS) in Italy

BACKGROUND

The importance of the standardisation of nucleic acid amplification technology (NAT) assays for the detection of hepatitis C virus RNA is well known today, as many studies carried out in different European countries attest. The results of a previous study performed in Italy (J. Clin. Virol. 1 (2003) 83) by the Italian Society of Clinical Microbiology (AMCLI) showed that the use of external reference standards and of multicentre collaborative studies significantly improves laboratory performance for the qualitative evaluation of HCV RNA.

OBJECTIVES

the AMCLI organised a new study on the standardisation of both the qualitative and the quantitative evaluation of HCV RNA with NAT in order to improve the implementation of the diagnostic methods for HCV RNA detection.

STUDY DESIGN

seventeen diagnostic centres of major Italian Hospitals participated in this quality control study. The study consisted of testing three panels, each made up of 10 coded samples including negative and positive samples. Positive samples contained four levels of HCV RNA (genotype 1).

RESULTS AND CONCLUSION

Seven out of 510 qualitative results obtained were incorrect (1.4%), two false negative and five false positive. The results gave a sensitivity of 99.5% and a specificity of 95.8%. Regarding quantitative tests, the geometric mean (GM) and standard deviation (S.D.) could be calculated only for the three highest HCV RNA levels. The percentage of results within the range of GM +/- 0.5 log(10) varied from 91% to 100%. Some laboratories had some difficulty in the exact quantification of the lowest (3.00 log IU/ml) as well as of the highest viral levels (6.35 log IU/ml) values, very near to the limits of the dynamic range of the assays. The comparison of the results of this study with that previously carried out one confirms that a regular participation in external quality assessment (EQA) assures the achievement of a high proficiency level in the diagnosis of HCV infection.

Zeptomole detection of a viral nucleic acid using a target-activated ribozyme

We describe a strategy for the ultra-sensitive detection of nucleic acids using "half" ribozymes that are devoid of catalytic activity unless completed by a trans-acting target nucleic acid. The half-ribozyme concept was initially demonstrated using a construct derived from a multiple turnover Class I ligase. Iterative RNA selection was carried out to evolve this half-ribozyme into one activated by a conserved sequence present in the hepatitis C virus (HCV) genome. Following sequence optimization of substrate RNAs, this HCV-activated half-ribozyme displayed a maximal turnover rate of 69 min(-1) (pH 8.3) and was induced in rate by approximately 2.6 x 10(9)-fold by the HCV target. It detected the HCV target oligonucleotide in the zeptomole range (6700 molecules), a sensitivity of detection roughly 2.6 x 10(6)-fold greater than that previously demonstrated by oligonucleotide-activated ribozymes, and one that is sufficient for molecular diagnostic applications.

Poisoned patients as potential organ donors: postal survey of transplant centres and intensive care units

BACKGROUND

The number of patients awaiting allograft transplantation in the UK exceeds the number of organs offered for transplantation each year. Most organ donors tend to be young, fit and healthy individuals who die because of trauma or sudden cardiac arrest. Patients who die from drug and poison intoxication tend to have similar characteristics but are less frequently offered as potential organ donors.

METHODS

A postal questionnaire survey of all transplantation centres and an equal number of intensive care units in the UK was undertaken. The use of kidney, heart, lung, liver and pancreas transplants from poisoned patients following deliberate methanol ingestion, cardiac arrest presumed secondary to cocaine overdose, accidental domestic carbon monoxide inhalation and industrial cyanide exposure were used as case scenarios.

RESULTS

Response rates were 70% for transplantation centres and 50% for intensive care unit directors. Over 80% of organs would be offered or discussed with transplant coordinators by intensive care unit directors. Transplantation physicians/surgeons would consider transplanting organs in up to 100% of case scenarios, depending on the organ and poisoning or intoxication involved.

DISCUSSION

The postal survey presented here shows that most transplantation physicians and surgeons and intensive care unit directors would consider those who die following acute drug intoxication and poisoning as potential organ donors. The previously reported literature shows in general that transplanted organs from poisoned patients have good long-term survival, although the number of reports is small. Poisoned patients are another pool of organ donors who at present are probably underused by transplantation services.