A new step toward standardization of serum hepatitis C virus-RNA quantification in patients with chronic hepatitis C

Undetectable Hepatitis C Viral Load Is Associated With Improved Outcomes Following Total Joint Arthroplasty

BACKGROUND

Previous reports establish that infection with hepatitis C virus (HCV) predisposes total joint arthroplasty (TJA) recipients to poor postoperative outcomes. The purpose of the present study is to assess whether variation in HCV VL influences perioperative outcomes following TJA.

METHODS

A multicenter retrospective review of all patients diagnosed with HCV who underwent primary TJA between January 2005 and April 2018 was conducted. Patients were stratified into 2 cohorts: (1) patients with an undetectable VL (U-VL) and (2) patients with a detectable VL (D-VL). Kaplan-Meier survivorship analysis was calculated with revision TJA as the end point. Subanalysis on the VL profile was done.

RESULTS

A total of 289 TJAs were included (U-VL:118 TJAs; D-VL:171 TJAs). Patients in the D-VL cohort had longer operative times (133.9 vs 109.2 minutes), higher intraoperative blood loss (298.4 vs 219.5 mL), longer inpatient hospital stays (4.0 vs 2.9 days), more postoperative infections (11.7% vs 4.2%), and an increased risk for revision TJA (12.9% vs 5.1%). Kaplan-Meier demonstrated that the U-VL cohort trended toward better survivorship (P = .17). On subanalysis of low and high VL, no difference in outcomes was appreciated.

CONCLUSION

TJA recipients with a detectable HCV VL have longer operative times, experience more intraoperative blood loss, have longer hospital length of stay, and are more likely to experience infection and require revision TJA. The blood loss, hospital length of stay, and revision rate findings should be interpreted with caution, however, as there are confounding factors. Our findings suggest that HCV VL is a modifiable risk factor that, can reduce the risk of infection and revision surgery. Additionally, serum HCV VL was not correlated with outcomes.

Evaluation of serological transfusion-transmitted viral diseases and mutliplex nucleic acid testing in malaysian blood donors

BACKGROUND

Transmission of infectious diseases is a recognized complication of blood transfusion and blood products. Nucleic acid testing (NAT) may contribute to improved efficiency of blood screening and thereby increase the safety margin for transfused blood.

METHODS

Unscreened blood samples from 1388 randomized donors were selected for this study at the Transfusion Medicine Unit of Hospital Universiti Sains Malaysia (HUSM). Informed consent was obtained from all donors and blood samples were tested for HIV, HBV and HCV serologically and by NAT assay.

RESULTS

Of the 1,388 tested samples, 1,360 were non-reactive for both assays. Four samples (0.29%) were both serologically and NAT reactive. The remaining twenty-four samples were divided into two groups. Of these, five samples (0.366%) were NAT reactive and nineteen samples (1.37%) were serologically reactive. However, serology confirmation tests run on the latter nineteen samples were non-reactive.

CONCLUSIONS

Hence, NAT adds benefit of detecting "false positive" reactions via standard serology, the cost of administering NAT also need further consideration and study.

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.

Trends for genetic variation of Hepatitis C Virus quasispecies in Human Immunodeficiency virus-1 coinfected patients

Chronic infection by Hepatitis C Virus (HCV) causes liver fibrosis, which is accelerated by unknown mechanisms in patients with HIV-1 coinfection. The evolution of HCV quasispecies in this setting of coinfection is not fully understood. To compare HCV quasispecies between HIV-HCV coinfection and HCV monoinfection, we sequenced 340 HCV clones from the HVR-1 and NS3 regions at two different time points in two groups of treatment-naïve patients with HCV-1a infection: (1) HIV-HCV positive (n=6); and (2) HIV negative-HCV positive (n=3). In HCV/HIV coinfection, we found a trend for reduced HCV genetic complexity and diversity, and a trend towards reduced dN/dS ratios in the HVR-1 region, especially in those patients with CD4<200cells/mm(3), who lost positive selective immune pressure in the HVR-1 region. Differences in immune regulation of HCV quasispecies in HIV coinfected individuals deserve further exploration to clarify the different outcomes of chronic hepatitis C noted between the immunocompromised and the immunocompetent host.

Cryoglobulinemia related to hepatitis C virus infection

A causal link among hepatitis C virus (HCV) infection and essential mixed cryoglobulinemia, cryoglobulinemic glomerulonephritis, and vasculitis is strongly supported. HCV triggers autoimmune response in predisposed individuals that manifests as organ-specific and non-organ-specific autoantibodies and as polyclonal/monoclonal rheumatoid factor, which has a central role in causing damaging cryoglobulin and immune complex tissue levels. Immunologic events are mainly induced by HCV infection persistence, with excessive immune stimulation. Humoral immune dysfunction leads to autoantibodies and rheumatoid factor production with cryoglobulinemia, glomerulonephritis, vasculitis, neuropathy, and probably thyroiditis, and arthritis in rare cases. Cellular immune dysfunction leads to lymphocytic infiltration, proliferation, and cytokine production. Pegylated (or not) interferon-alpha in combination with ribavirin appears to be the treatment of choice for patients with symptomatic essential mixed cryoglobulinemia with or without glomerulonephritis. Novel treatment with rituximab is promising.

Analytical and biological variables influencing quantitative hepatitis C virus (HCV) measurement in HIV-HCV coinfection

The present review considers issues pertaining to the precision and variability of quantitative hepatitis C virus (HCV) measurement in general, outlines the characteristics of HCV RNA in HIV-HCV coinfection and evaluates those factors which may affect this measure. The clinical relevance of accurate HCV measurement in HIV-HCV coinfection is discussed.

Surveillance of the genetic variation in incident HIV, HCV, and HBV infections in blood and plasma donors: implications for blood safety, diagnostics, treatment, and molecular epidemiology

Surveillance for molecular variants in blood donors is vital to assuring that blood screening and supplemental assays are sensitive to circulating strains of blood-borne viruses. Blood screening and diagnostic assays licensed in the United States are largely based on prototype viral strains. Documentation of divergent viral strains in the donor pool can lead to accelerated development and licensure of robust serologic and nucleic acid amplification (NAT) assays for donor screening and diagnostic applications. In addition, surveillance for viral variants among donors has implications for assessing the prevalence of drug and vaccine escape mutants and for detecting and monitoring rare variants that may be newly introduced or increasing in the United States donor population. Combined NAT and serologic screening, supplemented by novel serologic testing strategies, can be used to identify donors with incident infections, which are of particular interest with respect to blood safety and public health implications. A systematic program is proposed for the genetic characterization of viral genomes in donors with incident HIV, HCV, or HBV infections.

Evaluation of the COBAS Hepatitis C Virus (HCV) TaqMan analyte-specific reagent assay and comparison to the COBAS Amplicor HCV Monitor V2.0 and Versant HCV bDNA 3.0 assays

Performance characteristics of the COBAS hepatitis C virus (HCV) TaqMan analyte-specific reagent (TM-ASR) assay using the QIAGEN BioRobot 9604 for RNA extraction were evaluated and compared to the COBAS Amplicor HCV Monitor V2.0 (Amplicor) and Versant HCV bDNA 3.0 (Versant) assays using clinical samples. Calibration of TM-ASR using Armored RNA allowed determination of the distribution of HCV RNA in clinical samples, using 22,399 clinical samples. Limit of detection, linearity, and inter- and intraassay assay precision were determined for the TM-ASR assay using multiple clinical specimen panels across multiple determinations. Genotype specificity for the TM-ASR assay was determined using samples with different HCV RNA genotypes evaluated and compared against predetermined results. Contamination control of the TM-ASR assay was evaluated using pools of HCV RNA-positive and -negative samples tested in a checkerboard pattern over 12 runs of 96 samples. Correlation of the TM-ASR, Amplicor, and Versant assays was determined using 100 paired clinical samples and Deming regression analysis. The TM-ASR performed well with respect to linearity, precision, and contamination control. The correlation between TM-ASR and the Amplicor and Versant assays was poor, with large differences between assay results for individual samples. Calibration of the TM-ASR assay with Armored RNA allowed for a wide dynamic range and description of the distribution of HCV RNA in clinical samples.

Longitudinal study in HIV/HCV-coinfected HAART-naive patients and role of HCV genotype

To evaluate the impact of highly active antiretroviral therapy (HAART) on the course of hepatitis C (HCV) infection, we studied the biological and virological characteristics of 23 HCV/HIV-coinfected HAART-naive patients. The HCV genotype, HCV and HIV viral loads, serum alanine aminotransferase, CD4+ and CD8+ cell/mm3 were determined at baseline, 1 month, 6 months and 12 months after initiation of HAART. Results were analyzed both in terms of total population and of HCV genotype. The study of the total population suggests that this therapy did not determine a significant alteration of HCV viremia and levels of ALT, while a significant decrease in HIV viremia (-1.7log10 at one year from the start of HAART) and increase in CD4+ counts was observed (P < 0.005). The biological and virological parameters of HCV/HIV coinfection differed according to the HCV genotype. In particular, only genotype 4 showed a significant inverse correlation between HCV and HIV viral loads.

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.

Hepatitis B vaccine efficacy in patients with chronic liver disease by hepatitis C virus

BACKGROUND

Considering the immunosuppression of patients with chronic liver disease, their response to vaccination is discussed in literature.

AIMS

To evaluate the response of hepatitis B vaccine in patients with chronic hepatitis C virus infection.

METHODS

This is a prospective study in which 85 patients with chronic hepatitis C virus infection (46.8 +/- 9.4 years, 44.7% males) and 46 healthy adults (36.7 +/- 11.1 years; 39.1% males) were evaluated. Confirmation of hepatitis C virus was obtained by the technique of polymerase chain reaction. Viral load was determined by the branched DNA method in 74 patients, and genotype was determined by sequencing in 73 patients. All patients and healthy adults received three doses of Engerix B vaccine IM (at 0, 30 and 180 days). Serological responses to the vaccine were divided into three categories: seroprotection, when anti-HBs was > or =100 mUI/mL; seroconversion, when anti-HBs was 10-99 mUI/mL, and non-reagent, when anti-HBs was <10 mUI/mL.

RESULTS

The response of hepatitis B vaccine as determined 1 month following dose 3 was seroprotection in 37.7%, seroconversion in 17.6% and non-reagent in 44.7% among patients and 84.8%, 13.0%, 2.2%, respectively in healthy adults. The number of non-reagent responses was significantly higher among those patients with chronic liver disease. Sixty-five patients with chronic hepatitis were compared to 20 compensated cirrhotic patients in concern to the response to vaccine, but no difference was found. The response to vaccine in patients with genotypes 2 or 3 (n = 40) was better than in those with genotype 1 (n = 33). Response was not related to serum HCV-RNA concentration.

CONCLUSION

The number of non-responders was higher in patients with chronic hepatitis C virus infection, irrespective of histological status and viral load. It is suggested that such patients should receive a double dose of vaccine, particularly the ones with genotype 1.

The use of class-I HLA tetramers for the detection of hepatitis C virus NS3-specific CD8(+) T cells in patients with chronic infection

BACKGROUND/AIMS

New methods to detect virus-specific T-cell responses have recently been developed. Several human leukocyte antigen (HLA)-peptide tetramers for the detection of hepatitis C virus (HCV)-specific CD8(+) T cells are under evaluation.

METHODS

Evaluation of one HLA class I-tetramer (HCVNS3-2) for the detection of HCV NS3-specific CD8(+) T cells in a series of 38 HLA-A2(+) chronically infected patients.

RESULTS

Almost half (42%) of the patients had detectable NS3-specific CD8(+) T cells. The frequencies of such cells ranged from 0.01% to 0.22% of total CD8(+) T cells. No significant differences in clinical features or mean viral load were detected between patients with or without tetramer + CD8(+) T cells.

CONCLUSIONS

The tetramer HCVNS3-2 may be very useful for the study of the HCV-specific CD8(+) immune response. Combination of this reagent with other tetramers based on other HCV peptides may help in the understanding of the immune response to the virus. However, a panel of tetramers based on several parts of the HCV polyprotein may be a mandatory requirement to explore the whole breadth of the CD8(+) T-cell response against HCV and to detect that response in the majority of patients with chronic infection.

Genetic variability of hepatitis C virus NS3 protein in human leukocyte antigen-A2 liver transplant recipients with recurrent hepatitis C

The association between the severity of chronic hepatitis C and the variability of the hepatitis C virus (HCV) genome remains controversial, but to our knowledge few data are available to date regarding T-cell epitope coding regions in transplant patients. In the current study, we identified 21 human leukocyte antigen (HLA)-A2-positive Spanish patients with chronic hepatitis C, 14 immunosuppressed liver transplant recipients, and 7 immunocompetent controls. Alanine aminotransferase, aspartate aminotransferase, viral load, and rate of fibrosis progression were determined. Genetic distances of HCV isolates and variations in epitopes of the HCV nonstructural 3 protein (NS3-1393 LIFCHSKKK and NS3-1406 KLVALGINAV) were compared between patients with slow or fast progression of fibrosis. Isolates from transplant patients with fast progression were found to be more divergent (P =.03), had a higher mean value of synonymous (dS) variations (P =.02), and some were differentiated in a phylogenetic tree, compared with isolates from patients with slow progression. The HLA-A2-restricted NS3-1406 epitope was found to be more variable (20 of 21 isolates differed from the prototype) compared with the A3-restricted NS3-1392 epitope (19% vs. 1.25% variation). A shift in the viral peptide was not detected in a subset of transplant patients, but was evident in two of three nontransplant patients with follow-up. There was no correlation noted between a particular amino acid variation and fibrosis progression (slow or fast) in either transplant or nontransplant patients. The results of the current study suggest that 1) there may be different HCV-1b strains in our geographic area, 2) immunosuppression appears to have little effect in amino acid variation at the HCV NS3-1406 epitope, and 3) variations over time might be more frequent in nonimmunosuppressed patients.

Performance attributes of the LCx® HCV RNA quantitative assay

The LCx HCV RNA quantitative assay (Abbott Laboratories, North Chicago, IL) is designed to use competitive reverse transcriptase-polymerase chain reaction (RT-PCR) and microparticle enzyme immunoassay (MEIA), in combination with a modified Qiagen sample preparation method, to measure the level of hepatitis C virus (HCV) in human plasma and serum. The assay provides quantitative results in international units (IU) of HCV RNA/ml, in copies of HCV RNA/ml, or their log (base 10) equivalents. A conversion study determined that 1IU equals 4.3 copies. The LCx HCV assay detected HCV RNA transcripts representative of genotypes 1-6 with near equal efficiency. The assay did not cross-react with high concentrations of 21 potentially cross-reactive microorganisms or with 100 HCV-negative specimens. The lower limit of detection was demonstrated to be 23IU/ml. The LCx assay had similar sensitivity to the Roche Amplicor HCV (version 2.0) qualitative assay when used to test panels containing 6, 12, 23, and 47IU/ml. The assay linear range was shown to extend from 23 to 2.3millionIU/ml. The intra-assay standard deviation (S.D.) was < or =0.066 logIU/ml for the four HCV positive samples tested, while for the same samples the observed inter-assay S.D. was < or =0.075 logIU/ml. The overall mean assay quantitation value for seven HCV-positive WHO-standardized Acrometrix NAP linearity panel members was within 0.06 logIU/ml of the mean assigned value. The assay was demonstrated to correlate acceptably against the Roche Amplicor HCV monitor test (version 2.0). These data suggest that the assay is standardized appropriately against the WHO standard across its linear range and can be used for quantitation of HCV. In addition, with a sensitivity of 23IU/ml, the assay can be used to determine if post-therapy viral clearance has occurred.

Review article: indicators and predictors of response to anti-viral therapy in chronic hepatitis C

The complications of chronic hepatitis C, including cirrhosis and hepatocellular carcinoma, are expected to increase dramatically world-wide over the next 10-20 years. Immunomodulatory/anti-viral therapy, employing interferon alfa both alone and in combination with ribavirin, affords the only effective treatment for hepatitis C. Accurate early prediction of response to interferon therapy may decrease or eliminate unnecessary or ineffective treatment, permit greater flexibility in tailoring therapy on an individual basis, and enhance the cost-effectiveness of treatment. Liver biopsy provides valuable information about the baseline severity and subsequent progression of hepatitis C. Severe fibrosis or cirrhosis on the pre-treatment liver biopsy is associated with decreased response rates. The measurement of viral RNA levels and genotyping may be used to optimize individual patient treatment. Genotype non-1 and a low viral load are the most significant pre-treatment indicators of sustained virological response. The most reliable predictor of a poor virological response is continued seropositivity for viral RNA during therapy. Therefore, a decision to stop or continue treatment can be based on a positive viral RNA test at 12 weeks for interferon-naive patients receiving interferon or pegylated interferon therapy.

Hepatitis C virus infection in children coinfected with HIV: epidemiology and management

Mothers with hepatitis C virus (HCV) and HIV coinfection are the major source of HCV/HIV coinfection in infancy and childhood. There is no known intervention capable of interrupting HCV spread from mother to child, while the majority of infant HIV infections occurring in the developed world can be prevented by antiretroviral prophylaxis in the mother and child, elective caesarean section, and formula-feeding. In the era preceding treatment of HIV infection with highly active antiretroviral therapy, HCV coinfection was of little concern because the short-term survival of patients with HIV infection prevented the slowly developing consequences of chronic hepatitis C. As the life expectancy of patients with HIV infection increased with therapy, HCV has emerged as a significant pathogen. Several lines of evidence in adult patients suggest that liver disease may be more severe in patients coinfected with HIV and that progression of HIV disease may be accelerated by HCV coinfection. Whether coinfected children may share these clinical patterns remains a matter of speculation. Chronic hepatitis C in otherwise healthy children is usually a mild disease; liver damage may be sustained and fibrosis may increase over the years, suggesting slow progression of the disease. Interferon-alpha has been the only drug used in the past decade to treat hepatitis C in children and adolescents, with average response rates of 20%. Preliminary results of treatment with interferon-alpha and ribavirin suggest that the efficacy would be greater with combined therapy. These treatment protocols have not yet been applied to children coinfected with HIV, but the increasing number of long-term survivors will probably prompt further investigation in the near future. At present, treating HIV disease and monitoring HCV infection and hepatotoxicity induced by antiretroviral drugs seem to be the more reasonable approach to HCV/HIV coinfection in childhood.

Use and interpretation of hepatitis C virus diagnostic assays

The HCV genotype, HCV RNA, HCV core antigen, and anti-HCV antibodies are the four biologic markers currently used in hepatitis C. Acute and chronic hepatitis C are diagnosed by anti-HCVantibody (enzyme immunoassay) and HCV RNA detection with sensitive molecular biology techniques. Other virologic tools include HCV genotype determination and HCV RNA quantification; these are used to guide the individual treatment choice, and also to monitor treatment efficacy. Overall, the management of HCV infection has been vastly improved by the use of virologic assays. These assays remain to be fully standardized and automated, however, and more clinically relevant cut-off values are required on which to base management recommendations. More sensitive and accurate HCV RNA assays will improve not only the assessment of the response to antiviral treatment, but also our understanding of antiviral resistance. These improvements, and the development of new antiviral drugs (see the article by Drs. DeFrancesco and Rice elsewhere in this issue), should help to optimize the treatment of HCV infection.

Use and interpretation of virological tests for hepatitis C

Four virological markers of hepatitis C virus (HCV) infection are used clinically for management of patients with hepatitis C, namely the HCV genotype, HCV RNA, HCV core antigen, and antibody to HCV (anti-HCV). The diagnosis of acute and chronic hepatitis C is based on both anti-HCV detection using enzyme immunoassays (EIA) and HCV RNA detection using a sensitive molecular biology-based technique. Other virological tools, including HCV genotype determination and HCV RNA quantification, are now used to tailor treatment to the individual patient and to determine its efficacy. This article reviews the kinetics of HCV markers during acute and chronic HCV infection, together with current assays and their practical use in the management of HCV-infected patients.

Use and interpretation of virological tests for hepatitis C

Four virological markers of hepatitis C virus (HCV) infection are used clinically for management of patients with hepatitis C, namely the HCV genotype, HCV RNA, HCV core antigen, and antibody to HCV (anti-HCV). The diagnosis of acute and chronic hepatitis C is based on both anti-HCV detection using enzyme immunoassays (EIA) and HCV RNA detection using a sensitive molecular biology-based technique. Other virological tools, including HCV genotype determination and HCV RNA quantification, are now used to tailor treatment to the individual patient and to determine its efficacy. This article reviews the kinetics of HCV markers during acute and chronic HCV infection, together with current assays and their practical use in the management of HCV-infected patients.

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

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

Review of the effect of highly active antiretroviral therapy on hepatitis C virus (HCV) RNA levels in human immunodeficiency virus and HCV coinfection

The effect of anti-human immunodeficiency virus (HIV) treatment on hepatitis C virus (HCV) RNA levels in HIV-HCV-coinfected persons is uncertain. Although it is commonly believed that, with the initiation of HIV treatment, there may be an initial increase followed by a gradual decrease of HCV RNA levels to lower than those at pretreatment, the published studies evaluating this are of small and heterogeneous populations, are limited in follow-up, and have conflicting results. A prospective clinical trial of sufficient size and duration may help clarify this issue. This may be clinically relevant, because lower HCV RNA levels are a predictive factor for favorable response to HCV antiviral therapy.

Comparison of methodologies for quantification of hepatitis C virus (HCV) RNA in patients coinfected with HCV and human immunodeficiency virus

Quantification of hepatitis C virus (HCV) RNA is important in the assessment of HCV-associated liver disease in patients coinfected with HCV and human immunodeficiency virus (HIV). To investigate whether the standard integrity of competing test methodologies might be compromised by higher HCV titers in coinfected patients, 2 technologies (a polymerase chain reaction-based assay [COBAS Amplicor 2.0 assay; Roche Diagnostics] and a branched-chain DNA assay [Versant 3.0; Bayer]) were evaluated by testing paired serum samples from 68 coinfected patients and 137 HCV-monoinfected patients. Although the correlation was highly significant (r=0.81; P<.001), HCV RNA titers expressed in international units per milliliter could not be standardized; statistically significant differences were observed in all quartiles. Significant variability (P<.0007) was observed in the classification of patients as having a high versus a low virus titer (cutoff, 800,000 IU/mL), which suggests that standardization in international units has low efficacy among coinfected patients. Clinicians should note that test variability precludes direct comparability of HCV RNA titers, particularly in coinfected patients with high titers.

Early detection of nonresponse to interferon plus ribavirin combination treatment of chronic hepatitis C

We have investigated the value of early hepatitis C virus (HCV) RNA decline (DeltaHCV RNA) to predict response to combination therapy in 66 chronic hepatitis C patients treated with IFN-alpha2b (3 MU thrice weekly) and ribavirin (800 mg daily) for 12 months [25 sustained responders (SR) and 41 nonresponders or relapsers (NR)]. Serum HCV RNA was retrospectively measured in samples obtained at baseline and 4, 8 and 12 weeks after treatment onset, using a commercially available quantitative RT-PCR assay. At 4 weeks, serum HCV RNA had decreased a mean of 2.6 +/- 0.8 logs among SR as compared with only 0.5 +/- 0.8 logs in NR (P < 0.001), and was already undetectable (< 600 IU/mL) in 12 (48%) of the SR but in none of the NR. At 8 weeks, HCV RNA was undetectable in 21 SR and in 2 NR and mean DeltaHCV RNA were 4.2 +/- 1.3 and 0.8 +/- 1.0 logs, respectively (P < 0.001). At week 12 all SR had undetectable HCV RNA as compared with only five NR (P < 0.001). Stepwise logistic regression analysis identified DeltaHCV RNA at 12 weeks as the strongest predictor of sustained response. Receiver operating characteristic (ROC) curves of DeltaHCV RNA for sustained response prediction identified sensitivity peaks with 100% negative predictive value corresponding to DeltaHCV RNA > 1 log at 4 weeks, > 2 logs at 8 weeks and > 3 logs at 12 weeks. Our results show that early changes in the HCV RNA level may reliably identify patients having no chance of a sustained virological response during the first 3 months of combination therapy, thus providing an excellent tool for optimizing antiviral treatment of chronic hepatitis C.

Molecular diagnosis of viral hepatitis

Molecular biology-based assays are invaluable tools for the management of chronic viral hepatitis. They can be used to test blood donations, diagnose active infection, help to establish the prognosis, guide treatment decisions, and assess the virological response to therapy. This article reviews current molecular biology-based techniques and assays, and their practical use in the management of hepatitis B and C virus infection.

Quantitation of hepatitis C virus RNA by third generation branched DNA-based signal amplification assay

Quantitation of hepatitis C virus (HCV) RNA has become an important tool in different clinical settings and is used extensively for pretreatment evaluation of patients infected chronically with HCV. In this study, the performance characteristics of the third generation branched DNA-based signal amplification assay (bDNA 3.0) for HCV RNA quantitation were established. The new assay version showed an analytical specificity of 98%. Mean intra- and between-run imprecisions were 6.8 and 11.2%, respectively. The assay was linear over its entire dynamic range. Quantitation appeared to be unaffected by the genotypic variability of HCV. A comparison of bDNA 3.0 with the second generation bDNA assay calibrated against the international WHO HCV RNA standard, and the PCR-based Cobas Amplicor HCV Monitor 2.0 revealed a fairly good correlation among the assays. Twenty-nine and 11% of the paired quantitative results differed by more than log(10)0.5 (i.e. three-fold). All three assays after calibration against the WHO standard also yielded clinically comparable results with regard to the tailoring of interferon alpha/ribavirin treatment duration in patients infected by HCV genotypes 1, 4, and 5.

Comparative evaluation of the VERSANT HCV RNA 3.0, QUANTIPLEX HCV RNA 2.0, and COBAS AMPLICOR HCV MONITOR version 2.0 Assays for quantification of hepatitis C virus RNA in serum

A comparison of quantitative results expressed in hepatitis C virus (HCV) international units per milliliter, obtained from the VERSANT HCV RNA 3.0 (bDNA-3.0) assay, the QUANTIPLEX HCV RNA 2.0 (bDNA-2.0) assay, and the COBAS AMPLICOR HCV MONITOR version 2.0 (HCM-2.0) test was performed. A total of 168 patient specimens submitted to the Mayo Clinic Molecular Microbiology Laboratory for HCV quantification or HCV genotyping were studied. Of the specimens tested, 97, 88, and 79% yielded quantitative results within the dynamic range of the bDNA-3.0, bDNA-2.0, and HCM-2.0 assays, respectively. Overall, there was substantial agreement between the results generated by all three assays. A total of 15 out of 29 (52%) of the specimens determined to contain viral loads of <31,746 IU/ml by the bDNA-3.0 assay were categorized as containing viral loads within the range of 31,746 to 500,000 IU/ml by the bDNA-2.0 assay. Although substantial agreement was noted between the results generated by the bDNA-2.0 and bDNA-3.0 assays, a bias toward higher viral titer by the bDNA-2.0 assay was noted (P = 0.001). Likewise, although substantial agreement was noted between the results generated by the HCM-2.0 and bDNA-3.0 assays, a bias toward higher viral titer by the bDNA-3.0 assay was noted (P < or = 0.001). The discrepancy between the HCM-2.0 and bDNA-3.0 results was more pronounced when viral loads were >500,000 IU/ml and resulted in statistically significant differences (P < or = 0.001) in determining whether viral loads were above or below 800,000 IU/ml of HCV RNA, the proposed threshold value for tailoring the duration of combination therapy. The expression of quantitative values in HCV international units per milliliter was a strength of both the bDNA-3.0 and HCM-2.0 assays.

Serum tumour necrosis factor-alpha and transforming growth factor-beta levels in chronic hepatitis C patients are immunomodulated by therapy

Our aims were: (i) to characterize serum levels of tumour necrosis factor alpha (TNF-alpha) and transforming growth factor beta (TGF-beta) in non-cirrhotics with hepatitis C; (ii) to correlate levels of theses cytokines with degree of disease at baseline; (iii) to characterize the immunomodulatory effects of therapy with response and (iv) to compare profiles of cytokines in patients treated with pegylated-interferon alpha-2b monotherapy (PMT) vs its combination with ribavirin (PCT1-low dose ribavirin and PCT2-high dose ribavirin). We studied 56 patients that were part of two randomized, controlled, clinical trials. At baseline, high TNF-alpha levels paralleled the degree of inflammation as determined by histology. In PCT2, a significant reduction was seen in levels of TNF-alpha, TGF-beta and fibrosis scores when comparing baseline with follow-up. In sustained responders, regardless of therapy, the histological activity scores were lower at follow-up as compared to baseline. In conclusion, PCT2 is able to constantly reduce and sustain TNF-alpha levels, which is responsible for the sustained decline in liver inflammation as shown by the histological activity index and it is also able to reduce fibrosis as judged both by TGF-beta levels and fibrosis scores.

Advances in the molecular diagnosis of hepatitis C and their clinical implications

Serologic assays for diagnosis of hepatitis C infection may yield indeterminate results despite improvements in sensitivity and specificity through second- and third-generation assays. Direct detection of hepatitis C virus (HCV) RNA based on qualitative reverse transcription-polymerase chain reaction or transcription-mediated amplification allows diagnosis in the early stages of acute infection and in patients unable to mount an antibody response. Quantitative HCV RNA assays are useful for selecting appropriate antiviral therapies, but until recently they have lacked comparability between tests. More sensitive qualitative assays should be used for determining duration of treatment or recognizing a sustained virologic response to therapy. Hepatitis C virus genotyping can be performed from a limited sequence analysis of the viral genome by using various techniques. Although newer genotyping methods are relatively practicable and are satisfactory for the discrimination of the majority of genotypes, discrimination between subtypes can be challenging. Serologic typing of HCV lacks sensitivity and specificity compared with molecular-based techniques. Recent advances in serologic assays and nucleic acid detection techniques allow physicians to make accurate diagnoses, and these assays serve as important tools in treatment planning.

Advances in the molecular diagnosis of hepatitis C and their clinical implications

Serologic assays for diagnosis of hepatitis C infection may yield indeterminate results despite improvements in sensitivity and specificity through second- and third-generation assays. Direct detection of hepatitis C virus (HCV) RNA based on qualitative reverse transcription-polymerase chain reaction or transcription-mediated amplification allows diagnosis in the early stages of acute infection and in patients unable to mount an antibody response. Quantitative HCV RNA assays are useful for selecting appropriate antiviral therapies, but until recently they have lacked comparability between tests. More sensitive qualitative assays should be used for determining duration of treatment or recognizing a sustained virologic response to therapy. Hepatitis C virus genotyping can be performed from a limited sequence analysis of the viral genome by using various techniques. Although newer genotyping methods are relatively practicable and are satisfactory for the discrimination of the majority of genotypes, discrimination between subtypes can be challenging. Serologic typing of HCV lacks sensitivity and specificity compared with molecular-based techniques. Recent advances in serologic assays and nucleic acid detection techniques allow physicians to make accurate diagnoses, and these assays serve as important tools in treatment planning.

Stability of HCV-RNA level and its lack of correlation with disease severity in asymptomatic chronic hepatitis C virus carriers

This study examines the relationship between HCV-RNA levels and disease severity in 60 individuals with chronic hepatitis C virus infection. HCV-RNA levels were quantified by the branched DNA (bDNA) assay in 445 samples (median: eight samples per patient) obtained over a median of 40.4 months (95% confidence interval (CI): 37.0-42.5). The median log HCV-RNA level was 6.77 (95% CI: 6.62-6.92) molecular equivalents/mL (MEQ/mL). The median log range of HCV-RNA levels in individual patients over the course of the study was 0.89 (95% CI: 0.69-1.16). HCV-RNA level varied over time by less than one log in 62% of patients, by 1-1.5 logs in 22% and by greater than 1.5 logs in only 17%. Univariate analysis, revealed an inverse association between HCV-RNA levels and ALT levels (P=0.037). Univariate and logistic regression analysis showed no significant association between HCV-RNA levels and either the degree of inflammation or fibrosis. In contrast, there was a significant positive association between alanine aminotransferase (ALT) levels and histological activity especially in individuals with ALTs> 100 IU/L. Hence, HCV-RNA levels: (i) almost always fell within the dynamic range of the bDNA assay; (ii) were stable in asymptomatic chronically infected patients, with only a small proportion of patients exceeding a range of 1.5 logs; (iii) did not correlate with either the extent of inflammation or degree of fibrosis. In contrast, there was a strong association between ALT level and the histological severity of liver disease.

Viral hepatitis

Viral hepatitis constitutes the most common entity seen in hepatology practice. Hepatitis A vaccination is recommended for patients with chronic hepatitis. Both lamivudine and interferon are established therapies against chronic hepatitis B, with other treatments not equally effective. Adefovir dipivoxil is a promising new treatment for lamivudine-resistant hepatitis B mutants. Lamivudine and hepatitis B immunoglobulin are effective in preventing recurrence of hepatitis B after transplantation. The combination of interferon and ribavirin has been shown to be effective for treatment of hepatitis C. Studies support the antiviral, antifibrotic, and antineoplastic effect of interferon therapy. Recurrence of hepatitis C after transplantation has been associated with more rapid progression to cirrhosis. Other major advances in the field of viral hepatitis during the past year are highlighted.

Interferon-alpha and ribavirin for the treatment of recurrent hepatitis C after liver transplantation

BACKGROUND

Initial studies utilizing interferon-alpha and ribavirin for the treatment of recurrent hepatitis C virus (HCV) infection after liver transplantation showed promising results. Here we report our single-center experience using this combination therapy.

METHODS

Liver transplant recipients with recurrent HCV (elevated serum aminotransferases, positive serum HCV RNA, and biopsy-proven hepatitis without rejection) received interferon-alpha (1.5-3 million units subcutaneously three times a week) and ribavirin (400-1000 mg p.o. daily) for 12 months or more. Serum aminotransferases, HCV RNA, and severity of hepatitis were followed.

RESULTS

Thirty-two patients have been treated for at least 3 months, including 13 who have been on 12 or more months of therapy. Three died from allograft failure due to recurrent HCV. Dose reductions of interferon-alpha and/or ribavirin occurred in 22 patients. Thirteen had their medications permanently discontinued for severe adverse effects. Twenty-six patients (81%) had a biochemical response (BR; normalization of serum aminotransferases) after 3 months. End-of-treatment and sustained BR were 77% and 71%, respectively. Mean viral loads decreased 68-77%; however, only three patients became serum HCV RNA negative. After 12 months of therapy, no histological improvement was observed in 11 patients who were biopsied. Patients who received mycophenolate mofetil or daclizumab had a less likelihood of achieving a BR.

CONCLUSIONS

A significant number of patients did not tolerate interferon-alpha or ribavirin. Although BR was excellent and mean viral loads decreased significantly, virological clearance was poor and no histological improvement was noted. A more efficacious treatment with less adverse effects for recurrent HCV after liver transplantation is needed.

Strategy for the maximization of clinically relevant information from hepatitis C virus, RT-PCR quantification

BACKGROUND

The increasing clinical application of viral load assays for monitoring viral infections has been an incentive for the development of standardized tests for the hepatitis C virus.

OBJECTIVE

To develop a simple model for the prediction of baseline viral load in individuals infected with the hepatitis C virus.

METHODOLOGY

Viral load quantification of each patient's first sample was assessed by RT-PCR-ELISA using the Roche MONITOR assay in triplicate. Genotype of the infecting virus was identified by reverse line probe hybridization, using amplicons resulting from the qualitative HCV Roche AMPLICOR assay.

RESULTS

Retrospective evaluation of first quantitative values suggested that 82.4% (n=168/204) of individuals had a viral load between 4.3 and 6.7 log(10) viral copies per ml. A few patients (3.4%; n=7/204) have a serum viremia less than the lower limit of the linear range of the RT-PCR assay. Subsequent, prospective evaluation of hepatitis C viral load of all new patients using a model based on the dynamic range of viral load in the retrospective group correctly predicted the dynamic range in 75.9% (n=33/54).

CONCLUSION

The dynamic range of hepatitis C viremia extends beyond the linear range of the Roche MONITOR assay. Accurate determination of serum viremia is substantially improved by dilution of specimens prior to quantification.

Evaluation of hepatitis C virus RNA RT/PCR qualitative and quantitative second generation assays

Hepatitis C virus (HCV) RNA qualitative and quantitative second generation assays (Amplicor HCV v2.0 and Amplicor HCV Monitor v2.0, respectively) were evaluated by testing serum samples from 132 blood donors anti-HCV positive HCV RNA negative by first generation qualitative assay and 326 viremic patients. An HCV RNA transcript was synthesized and ten-fold dilutions were used to assess sensitivity. Second generation assays were one log more sensitive than their respective first generation tests (10(2) copies per ml vs. 10(3) for the qualitative tests; 10(3) copies per ml vs. 10(4) for the quantitative tests). From the 132 anti-HCV positive RNA negative subjects, 6 (5%) were positive by Amplicor v2.0. Quantification figures by Monitor v2.0 were similar in genotypes 1, 2 and 3, whereas Monitor 1.0 values were higher in genotype 1 than in genotype 2 or 3. In 114 patients, branched-DNA v2.0 obtained higher values than Monitor v2.0 and Monitor v1.0 (6.6+/-0.6 log RNA copies per ml, 6.4+/-0.6, and 5.3+/-0.7, respectively, P<0.001). HCV RNA qualitative and quantitative second generation assays are more sensitive and genotype independent than first generation assays.

Standardization of hepatitis C virus RNA quantification

It was recently recommended that hepatitis C virus (HCV) RNA quantification be used to tailor the duration of combined interferon alfa (IFN-alpha)/ribavirin therapy in patients infected by HCV genotypes 1, 4, and 5. This recommendation has been difficult to implement in the absence of standardized quantitative units for HCV RNA. The aim of this work was to define clinically relevant HCV RNA loads in standardized international units (IU), for use in routine clinical and research applications based on standardized quantitative assays. Two hepatitis C virus RNA quantitative assays were used: (1) the Superquant assay (National Genetics Institute, Los Angeles, CA), for which possibly relevant thresholds were established; and (2) the semi-automated Cobas Amplicor HCV Monitor assay version 2.0 (Cobas v2.0, Roche Molecular Systems, Pleasanton, CA) that measures HCV RNA loads in IU/mL. Quantification in the Cobas v2.0 assay was linear over the entire range of values tested, including viral loads higher than 850,000 IU/mL after 100-fold dilution. The accuracy and precision of the measures in IU/mL were satisfactory with Cobas v2.0. The results obtained with Superquant and Cobas v2.0 correlated (r =.932; P <.0001). A value of 2,000,000 copies/mL (6.3 log(10) copies/mL) with Superquant was converted to nearly 800,000 IU/mL (5.9 log(10) IU/mL). In conclusion, all HCV RNA quantitative assays should give HCV RNA loads in international units and be validated with appropriate calibrated panels; 800,000 IU/mL in any of these assays should be used as the decision threshold to tailor the IFN-alpha/ribavirin treatment duration in patients infected by HCV genotypes 1, 4, and 5.