Performance of HCV core antigen and PCR testing in a predominantly genotype 3 population

Hepatitis C core antigen (HCVcAg) is becoming increasingly recognized as an alternative to molecular testing for the confirmation of chronic hepatitis C. However, there are limited data on the performance of this assay in a genotype 3 (GT3) predominant country like Pakistan. We conducted a study to evaluate the diagnostic performance of HCVcAg against the HCV polymerase chain reaction (PCR) molecular test. HCV antibody-positive patients requiring confirmatory testing were recruited from August to October 2018 at the Pakistan Kidney and Liver Institute and Research Center (PKLI&RC), Lahore, Pakistan. Patients with previously known diagnoses or treatment histories were excluded. The Abbott HCV Ag assay was used for HCVcAg testing. Results ≥3.00 fmol/L were considered positive for HCVcAg. The Abbott RealTime HCV assay was used for PCR testing with a lower detection limit of ≥12 IU/mL. We computed the sensitivity, specificity and correlation of HCVcAg against HCV PCR. A total of 394 patients were recruited. The median age of the patients was 42 years. Most participants were females (51.5%, n = 203), 30.7% (n = 121) had HTN, 10.4% DM (n = 41) and 5% had APRI ≥2. The overall sensitivity was 98.0% and the specificity was 98.6%. The lowest detection limit of cAg was an HCV RNA value of 4657 IU/mL. The levels of cAg were highly correlated with those of HCV RNA by Spearman's rank correlation test (r = 0.935, p < .001). HCVcAg represents a suitable alternative with high sensitivity and specificity compared with HCV PCR in the GT3-predominant population and can be incorporated into algorithms to improve linkage to care.

Performance of HCV Antigen Testing for the Diagnosis and Monitoring of Antiviral Treatment: A Systematic Review and Meta-Analysis

BACKGROUND AND AIMS

Active hepatitis C virus (HCV) infection is based on the detection of HCV RNA that it is effective but presents high cost and the need to hire trained personnel. This systematic review and meta-analysis is aimed at evaluating the diagnostic accuracy of HCV Ag testing to identify HCV cases and to monitor antiviral treatment including DAA treatment.

METHODS

The studies were identified through a search in PubMed, Lilacs, and Scopus from 1990 through March 31, 2020. Cohort, cross-sectional, and randomized controlled trials were included. Two independent reviewers extracted data and assessed quality using an adapted Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. Our primary outcome was to determine the accuracy of HCV Ag detection for the diagnosis, which we estimated using random-effects meta-analysis.

RESULTS

Of 3,062 articles identified, 54 met our eligibility criteria. The studies described cohorts from 20 countries, including 14,286 individuals with chronic HCV individuals. Studies for ECLIA technology demonstrated highest quality compared to studies that used ELISA. The pooled sensitivity and specificity (95% CI) for HCV Ag detection of active HCV infection were 98.82% (95%CI = 98.04%; 99.30%) and 98.95% (95%CI = 97.84%; 99.49%), respectively. High concordance was found between HCV Ag testing and HCV RNA detection 89.7% and 95% to evaluate antiviral treatment.

CONCLUSIONS

According to our findings, HCV Ag testing could be useful to identify HCV active cases in low-resource areas. For antiviral treatment, HCV Ag testing will be useful at the end of treatment.

Hepatitis C virus antigen detection is an appropriate test for screening and early diagnosis of hepatitis C virus infection in at-risk populations and immunocompromised hosts

Early diagnosis remains key for effective prevention and treatment. Unfortunately, current screening with anti-hepatitis C virus antibody (anti-HCV Ab) test may have limited utility in the diagnosis of HCV infection and reinfection. This is of special concern to at-risk population, such as immunocompromised hosts and end-stage renal failure patients on hemodialysis. HCV antigen (Ag) could be useful in identifying the ongoing infection in such clinical scenarios. Hence, we aimed to study the utility of HCV Ag testing for the diagnosis of acute and chronic hepatitis C. Of 89 samples studied, 19 were from acute hepatitis C patients who were immunocompromised or were on hemodialysis, 43 were from active chronic hepatitis C patients and 27 were from patients treated for chronic hepatitis C. All samples were tested for HCV Ag using the Abbott ARCHITECT HCV Ag assay. HCV Ag was reactive in 19/19 samples from acute hepatitis C patients and 42/43 samples from active chronic hepatitis C patients. It was nonreactive in all samples from treated patients. The test showed a sensitivity and specificity of 98.4% and 100.0%, respectively. The positive and negative predictive values were 100.0% and 96.4%, respectively. The HCV antigen test has high clinical sensitivity and specificity and is useful for the diagnosis of acute and chronic hepatitis C infection in at-risk and immunocompromised patients. Its short turnaround time and relatively low cost are advantageous for use in patients on hemodialysis and other at-risk patients who require monitoring of HCV infection and reinfection.

Utility of grey zone testing strategy in transfusion transmissible infection testing in blood bank is of limited value!

Several blood banks use grey zone (GZ) phenomenon (defined as samples with optical density within 10% below the cut off in enzyme immuno-assay [EIA]/chemiluminescence immunoassay [CLIA]) to further augment blood safety. There is paucity of data regarding usefulness of GZ sample and its application in Transfusion Transmissible Infection (TTI) screening procedures in blood transfusion services. We looked at our GZ sample results and their confirmatory test results to verify if it adds to blood safety in our set-up? We performed a prospective analytical study on blood donors' samples over two years. All the donors' samples were screened for TTI using CLIA. Samples with signal/cut-off ratio between ≥0.90 and <1.00 were classified under GZ. They were re-tested in duplicate and submitted to confirmatory testing: Neutralization Test for HBsAg, Immunoblot for HCV, and Western blot for HIV. Among the 50,064 blood donors donating the blood during study period, 573 (1.14%) donors were reactive for HBsAg, HCV, and HIV. Forty-seven (0.1%) TTI samples were GZ, but none was "confirmed positive." The utility of GZ testing seems to be limited. However, this may be continued for sake of "erring on the side of caution" and since this only results in negligible wastage (0.1%) of blood units.

Comparison of two immunoassays for concurrent detection of HCV antigen and antibodies among HIV/HCV co-infected patients in dried serum/plasma spots

Hepatitis C virus (HCV) antigen/antibody (Ag/Ab) assays offer the benefit of reducing the window period compared to assays that detect only HCV-Ab. In this study the performance of the Murex Ag/Ab (Murex, Abbott) and Monolisa Ag/Ab Ultra (Monolisa, Bio-Rad) ELISAs was compared for the use of filter dried serum/plasma spots (DS/PS) with a focus on the sensitivity and the percentage of correct positive test results. Correct positive ELISA results were assumed for samples that subsequently tested positive for HCV RNA by RT-qPCR, or RNA negative samples that tested positive in a Western blot (confirmed ELISA results). Sensitivity was evaluated from DS/PS eluates using HCV seroconversion panels [plasma samples of subtypes-(St) 1a, 2b)] and longitudinal HCV antibody positive serum panels (St 1b, 2b, 3a, and 4d). The proportion of correct positive test results was evaluated using 1102 newly diagnosed HIV positive clinical dried serum spots (DSS) eluates for screening of potential HCV co-infection. For the plasma HCV seroconversion samples, which were used as a reference for DSS eluates, the Murex became reactive earlier for antigen positive bleeds. However, for the HCV antibody positive eluates and dilutions thereof, the Monolisa demonstrated a superior sensitivity. Of the clinical DSS 22.8 % (28/123) of samples reactive in the Murex were negative in a subsequent RT-qPCR and Western blot, while only 1.9 % (2/105) of the samples reactive in the Monolisa were negative in these confirmatory assays. Our results indicate that the Monolisa provides fewer false positive results for HCV detection in DSS, whereas for undiluted plasma or serum samples, the Murex can serve as an additional diagnostic tool to narrow the window period.

HCV core antigen is a useful predictor during pegylated-interferon/ribavirin therapy in patients with hepatitis C virus genotype 1b

Enzyme immunoassays for quantifying hepatitis C virus (HCV) core antigen (Ag) have been proposed as an alternative to HCV RNA detection. The present study aimed to investigate the early kinetics of serum HCVcAg and its usefulness in predicting virological responses.The clinical data of 135 patients with chronic hepatitis C treated with pegylated interferon alpha (PEG-IFN-α) and ribavirin was retrospectively collected. The patients were grouped according to their treatment outcomes as follows: sustained virological response (SVR), nonsustained virological response (N-SVR), and relapse.Higher HCVcAg and HCV RNA levels were observed in patients in the N-SVR group than in the other groups at baseline. HCVcAg better predicted rapid virological response (RVR) compared with HCV RNA and had a predictive value similar to that of HCV RNA for SVR and early virological response. In the relapse group, HCV RNA decreased to 0 after 48 weeks, whereas HCVcAg was still detectable, indicating that HCVcAg more sensitively predicted relapse in antiviral therapy than HCV RNA.For patients treated with PEG-INF-α and ribavirin, HCVcAg may more sensitively predict relapse than HCV RNA.

'HepCheck Dublin': an intensified hepatitis C screening programme in a homeless population demonstrates the need for alternative models of care

BACKGROUND

Hepatitis C virus (HCV) is one of the main causes of chronic liver disease worldwide. Prevalence of HCV in homeless populations ranges from 3.9 to 36.2%. The HepCheck study sought to investigate and establish the characterisation of HCV burden among individuals who attended an intensified screening programme for HCV in homeless services in Dublin, Ireland.

METHODS

The HepCheck study was conducted as part of a larger European wide initiative called HepCare Europe. The study consisted of three phases; 1) all subjects completed a short survey and were offered a rapid oral HCV test; 2) a convenience sample of HCV positive participants from phase 1 were selected to complete a survey on health and social risk factors and 3) subjects were tracked along the referral pathway to identify whether they were referred to a specialist clinic, attended the specialist clinic, were assessed for cirrhosis by transient elastography (Fibroscan) and were treated for HCV.

RESULTS

Five hundred ninety-seven individuals were offered HCV screening, 73% were male and 63% reported having had a previous HCV screening. We screened 538 (90%) of those offered screening, with 37% testing positive. Among those who tested positive, 112 (56%) were 'new positives' and 44% were 'known positives'. Undiagnosed HCV was prevalent in 19% of the study sample. Active past 30-day drug use was common, along with attendance for drug treatment. Unstable accommodation was the most common barrier to attending specialist appointments and accessing treatment. Depression and anxiety, dental problems and respiratory conditions were common reported health problems. Forty-six subjects were referred to specialised services and two subjects completed HCV treatment.

CONCLUSIONS

This study demonstrates that the current hospital-based model of care is inadequate in addressing the specific needs of a homeless population and emphasises the need for a community-based treatment approach. Findings are intended to inform HepCare Europe in their development of a community-based model of care in order to engage with homeless individuals with multiple co-morbidities including substance abuse, who are affected by or infected with HCV.

HCV NS3Ag: a reliable and clinically useful predictor of antiviral outcomes in genotype 1b hepatitis C virus-infected patients

Since hepatitis C virus (HCV) non-structural 3 (NS3) protease inhibitor (PI) combined with pegylated interferon/ribavirin (PR) has been approved for chronic HCV genotype (GT) 1b infection, a reliable and clinically useful predictor combining with serum HCV RNA to predict early virologic response, breakthrough, and relapse is important during HCV antiviral treatment. We evaluated the role of HCV NS3 antigen (HCV NS3Ag) on the prediction of virologic response in patients with HCV GT1b during PR or PR/simeprevir (triple) therapy. Three hundred patients were recruited, and HCV RNA and HCV NS3Ag were tested at baseline and weeks 2, 4, 12, 24, 48, and 72. NS3Ag and HCV RNA were significantly related (r(2) = 0.67) in the whole patient selection. The kinetic pattern of HCV RNA and HCV NS3Ag during triple treatment was similar. HCV NS3Ag levels in the triple group closely followed those of HCV RNA; the r(2) values were 0.756 (baseline), 0.837 (2 weeks), 0.989 (4 weeks), and 0.993 (12 weeks), respectively. For patients treated with PR, the positive and negative predictive values (PPVs and NPVs) for viral response were 96.31 % and 67.19 %, respectively, at week 4 by using the decrease of NS3Ag (dHCV NS3Ag) combined with HCV RNA. At week 12, the PPV was similar at 94.16 %, while the NPV reached 87.26 %. The PPV and NPV for the prediction of relapse and breakthrough were 90.6 % and 76.7 %, respectively. HCV NS3Ag is a valuable marker and could be a supplementary predictor of HCV RNA for the prediction of antiviral response, breakthrough, or relapse during HCV antiviral treatment.

HEPATITIS C VIRUS (HCV) SEROPREVALENCE, ANTIGENAEMIA AND ASSOCIATED RISK FACTORS AMONG PREGNANT WOMEN IN NIGERIA

BACKGROUND & AIMS

Hepatitis C viral infection is a significant public health challenge with potential risk of progressing to liver cirrhosis and hepatocellular carcinoma (HCC). Actively infected mothers can transmit the virus to their babies who may develop liver cirrhosis and HCC as young adults. We determined the seroprevalence of HCV, its antigenaemia and associated risk factors among pregnant women.

METHODS

We recruited 400 pregnant women and tested their serum for HCV antibodies using immune-chromatographic test and determined the HCV core antigenaemia among HCV sero-positives by enzyme-immunoassay (EIA). The bio-socio-demographic variables of the participants were statistically correlated to the test results.

RESULTS

Seroprevalence of HCV was 5.8% (23/400) and the prevalence of HCV core antigenaemia was 73.9% (17/23). None of the bio-socio-demographic variables of the participants and other known risk factors evaluated had. significant influence on either seroprevalence of HCV or its antigenaemia. Only the employment status of the participants' husbands (p = 0.01) significantly affected seropositivity of HCV.

CONCLUSION

HCV core antigenaemia is high among pregnant women who have antibodies to HCV in our environment and this signifies an active hepatitis C virus infection.

Perinatal transmission of hepatitis C antigens: envelope 1, envelope 2 and non-structural 4

BACKGROUND

Perinatal exposure to hepatitis C virus (HCV) antigens during pregnancy may affect the developing immune system in the fetus. We aimed to study the perinatal transmission of HCV structural and non-structural antigens.

METHODS

Sera from 402 pregnant mothers were tested for anti-HCV antibody and HCV RNA. HCV antigens were determined in sera from 101 HCV-infected mothers and their cord blood.

RESULTS

In both serum and cord blood samples, HCV NS4 (non-structural 4) at 27 kDa, E1 (envelope 1) at 38 kDa and E2 (envelope 2) at 40 kDa were identified, purified and quantified using western blotting, electroelution and ELISA. Maternal sera and neonate cord blood samples had similar detection rates for NS4 (94.1%), E1 (90.1%) and E2 (90.1%). The mean maternal serum levels (optical density, OD) of HCV NS4 (0.87 ± 0.01), E1 (0.86 ± 0.01) and E2 (0.85 ± 0.01) did not differ significantly (p > 0.05) from those of neonatal cord blood (0.83 ± 0.01, 0.87 ± 0.01 and 0.85 ± 0.01, respectively). Also, strong correlations (p < 0.0001) were shown between sera and cord blood sample levels of HCV NS4, r = 0.77; E1, r = 0.76 and E2, r = 0.80. The vertical transmission of these antigens in vaginal delivery did not differ significantly (p > 0.05) from those in caesarean section.

CONCLUSIONS

These findings indicate that vertical transmission of HCV NS4, E1 and E2 antigens was very high. Thus, exposure to these antigens may influence the developing immune responses to natural infection or future vaccination.

Significance of the hepatitis C virus core antigen testing as an alternative marker for hepatitis diagnosis in Egyptian patients

OBJECTIVE

Hepatitis C virus (HCV) core antigen (Ag) quantification by enzyme-immunoassays has been proposed as an economic and simpler alternative to HCV RNA detection. The current study was undertaken to assess the significance of HCV core antigen assay for the diagnosis of chronic HCV infection and monitoring response to antiviral therapy in Egyptian patients.

PATIENTS AND METHODS

Sixty three HCV antibody positive patients and ten interferon-treated patients were included in the current study. The included patients were divided according to their viral load into four groups as follows; group I (n=10): HCV RNA loads ≤ 10000 IU/ml, group II (n=20): HCV RNA loads > 10000 ≤ 100000 IU/ml, group III (n=33): HCV RNA loads >100000 IU/ml and group IV (n=10): interferon-treated HCV patients with a negative HCV RNA.  Serum HCV core Ag and RNA loads were assayed and their correlations, including linear regression lines, were calculated.

RESULTS

HCV core Ag exhibited a non-significant (p > 0.05) difference between all the studied groups. Concerning, group I patients, HCV core Ag levels and HCV RNA loads were positively correlated, with a correlation coefficient of 0.73 (p < 0.05). Group II and III showed stronger correlations; the recorded values were 0.81 (p < 0.0001) and 0.94 (p < 0.0001) for group II and III, respectively.

CONCLUSIONS

HCV core Ag test can be used as an alternative to HCV RNA tests to evaluate chronic infection when the HCV RNA test is unavailable, but is not reliable enough for treatment monitoring.

Hepatitis C virus core antigen testing: Role in diagnosis, disease monitoring and treatment

While hepatitis B virus (HBV) screening relies on hepatitis B surface antigen to confirm HBV infection since the early days of hepatitis B disease management, hepatitis C virus (HCV) infection screening is based on anti-HCV testing which does not discriminate active from past infection. Thus to confirm infection HCV RNA testing has been required; recently a HCV core antigen assay became widely commercially available which could serve to confirm infection. That assay is less sensitive than current HCV RNA assays, but as more than 50% of anti-HCV positive persons will be HCV core antigen positive, HCV core antigen testing can be a cost effective and reflex test to confirm HCV infection in anti-HCV positive individuals and will be easier as it can be applied on the same platform. For treatment monitoring, more data need to be generated, but the early data available at present suggest that HCV core antigen may be an alternative to HCV RNA monitoring. With direct antivirals, HCV core antigen could even be superior to HCV RNA testing, as direct antivirals might already prevent virus formation when HCV core antigen is still produced and thereby correlates better with eventual viral clearance.

HCV antigen testing for the diagnosis of hepatitis C infection: a cost-efficient algorithm

BACKGROUND

In North America, diagnosis of active hepatitis C virus (HCV) infection is currently performed using RNA testing which is highly sensitive and specific but is associated with three major limitations: lability of RNA molecules, higher costs, and longer turn-around time as compared with commercially-available HCV core antigen testing. In the current study, a new HCV core antigen assay product was evaluated for the diagnosis of HCV infection and its cost reducing potential.

METHODS

Ninety plasma specimens positive for HCV RNA along with 25 negative HCV specimens were used for HCV antigen assay. Twenty-four specimens positive for a panel of agents were used for possible cross-reactivity. Sixty-four HCV antibody-positive specimens with negative HCV RNA and indeterminate HCV immunoblot results were also employed.

RESULTS

In the first group, 78/90 (86.6%) tested positive for HCV antigen with regression analysis showing no significant deviation from linearity. None of the prenatal specimens tested positive for HCV antigen. Non-specific reactions were not observed. In the HCV antibody-indeterminate group, only 2/64 (3.1%) were antigen positive. In the last group, none of the HCV antibody very-low-positive specimens tested positive for HCV antigen. Both inter- and intra-run reproducibility of 100% were noted. The cost analysis showed a minimum of 52.13% reduction in costs associated with qualitative RNA testing.

CONCLUSIONS

Considering the complexity of HCV infection diagnosis and the significant cost and turn-around time burden it imposes on clinical laboratories, HCV antigen testing seems an attractive adjunct to the current battery of laboratory diagnosis that demands more attention.

Prevalence and estimation of hepatitis B and C infections in the WHO European Region: a review of data focusing on the countries outside the European Union and the European Free Trade Association

Knowledge of hepatitis B and C prevalence, and numbers infected, are important for planning responses. Published HBsAg and anti-HCV prevalences for the 20 WHO European Region countries outside the EU/EFTA were extracted, to complement published data for the EU/EFTA. The general population prevalence of HBsAg (median 3·8%, mean 5·0%, seven countries) ranged from 1·3% (Ukraine) to 13% (Uzbekistan), and anti-HCV (median 2·3%, mean 3·8%, 10 countries) from 0·5% (Serbia, Tajikistan) to 13% (Uzbekistan). People who inject drugs had the highest prevalence of both infections (HBsAg: median 6·8%, mean 8·2%, 13 countries; anti-HCV: median 46%, mean 46%, 17 countries), and prevalence was also elevated in men who have sex with men and sex workers. Simple estimates indicated 13·3 million (1·8%) adults have HBsAg and 15·0 million (2·0%) HCV RNA in the WHO European Region; prevalences were higher outside the EU/EFTA countries. Efforts to prevent, diagnose, and treat these infections need to be maintained and improved. This article may not be reprinted or reused in any way in order to promote any commercial products or services.

Screening for hepatitis C virus infection in a high prevalence country by an antigen/antibody combination assay versus a rapid test

In low-income-countries, screening for hepatitis C virus (HCV) infection is often based on rapid tests (RT). Their lower sensitivity compared to enzyme immunoassay (EIA) suggests that newer HCV Antigen/Antibody (Ag/Ab) combination assays might have a role in such countries. To test this idea, 1998 blood donors were tested at the University Teaching Hospital blood bank in Yaoundé, Cameroon simultaneously with a RT (HCV rapid test, Human Diagnostics, Berlin, Germany) according to standard practice (S1) and with an Ag/Ab assay (Monolisa HCV Ag/Ab Ultra, Biorad, France) (S2). All discordant, borderline and reactive samples were submitted to confirmatory testing by immunoblot and/or HCV-RNA. Of the 86 (4.3%) samples positive with one or both strategies, 29 were confirmed negative, 37 positive and 20 were false positive or resolved infection. There was a significant difference in test sensitivity (p=0.01) between S1 (70.3%) and S2 (91.9%) but not in test specificity (99.4% and 98.6%, respectively). The benefit of the Ag/Ab assay in the detection of recent HCV seronegative infections could not be evaluated since no Antigen-only donations were identified. However, better Ag/Ab test sensitivity compared to RT supports the implementation of these newer immunoassays for HCV screening in the African blood bank setting.

Clinical utility of the ARCHITECT HCV Ag assay for early treatment monitoring in patients with chronic hepatitis C genotype 1 infection

BACKGROUND

Virologic response-monitoring is essential for determining therapy duration in patients with chronic hepatitis C virus (HCV) infection. This is usually performed using highly sensitive HCV-RNA assays. However, HCV-RNA assays are time-consuming, expensive and require highly trained personnel. Quantitative determination of HCV core-antigen (HCVAg) levels may be used to supplement treatment monitoring.

OBJECTIVES

The clinical utility of the ARCHITECT HCV Ag assay (Abbott Diagnostics) for response-guided therapy was investigated.

STUDY DESIGN

We analyzed serum from 160 patients with HCV genotype 1 infection who had been treated with peg-interferon alfa-2b/ribavirin. HCVAg levels were determined at baseline, weeks 1, 2, 4 and 12. HCVAg levels were compared to those obtained with HCV-RNA assays: VERSANT HCV Quantitative 3.0 (bDNA) and Qualitative (TMA, both Siemens Healthcare) assay and the Abbott RealTime HCV assay (ART; Abbott Diagnostics).

RESULTS

Baseline HCVAg levels correlated well with HCV-RNA as assessed by bDNA (r=0.91; p<0.0001) and ART (r=0.92; p<0.0001), respectively. Patients with undetectable HCVAg levels at week 1 had a 90.9% probability (positive predictive value) to achieve a rapid virologic response (HCV-RNA undetectable at week 4) based on TMA and 86.4% based on ART, respectively. Patients with less than 1 log(10) reduction in HCVAg between baseline and week 12 had a 90% probability (negative predictive value) to achieve a nonresponse (<2 log(10) decline in HCV-RNA between baseline and week 12) based on bDNA and 100% based on ART, respectively.

CONCLUSIONS

Determination of HCVAg may be useful for antiviral response-monitoring in patients with HCV genotype 1 infection.

Hepatitis C virus-multispecific T-cell responses without viremia or seroconversion among Egyptian health care workers at high risk of infection

Hepatitis C virus (HCV)-specific cell-mediated immunity (CMI) has been reported among exposed individuals without viremia or seroconversion. Limited data are available regarding CMI among at-risk, seronegative, aviremic Egyptian health care workers (HCW), where HCV genotype 4 predominates. We investigated CMI responses among HCW at the National Liver Institute, where over 85% of the patients are HCV infected. We quantified HCV-specific CMI in 52 seronegative aviremic Egyptian HCW using a gamma interferon (IFN-γ) enzyme-linked immunospot assay in response to 7 HCV genotype 4a overlapping 15-mer peptide pools covering most of the viral genome. A positive HCV-specific IFN-γ response was detected in 29 of 52 HCW (55.8%), where 21 (40.4%) had a positive response for two to seven HCV pools and 8 (15.4%) responded to only one pool. The average numbers of IFN-γ total spot-forming cells (SFC) per million peripheral blood mononuclear cells (PBMC) (± standard error of the mean [SEM]) in the 29 responding and 23 nonresponding HCW were 842 ± 141 and 64 ± 15, respectively (P < 0.001). Flow cytometry indicated that both CD4(+) and CD4(-) T cells produced IFN-γ. In summary, more than half of Egyptian HCW demonstrated strong HCV multispecific CMI without viremia or seroconversion, suggesting possible clearance of low HCV exposure(s). These data suggest that detecting anti-HCV and viremia to determine past exposure to HCV can lead to an underestimation of the true disease exposure and that CMI response may contribute to the low degree of chronic HCV infection in these HCW. These findings could have strong implications for planning vaccine studies among populations with a high HCV exposure rate. Further studies are needed to determine whether these responses are protective.

Characterization and application of monoclonal antibody against hepatitis C virus nonstructual protein three

Developing assays for detecting HCV antigens could be beneficial because viral proteins appear earlier than antibodies and are more stable than RNA in the serum. Monoclonal antibody was prepared by immunization and cell fusion. Subclass, specificity, and efficiency of monoclonal antibodies were determined by ELISA. Epitope specificity of monoclonal antibodies was analyzed by ELISA additivity test. HCV antigen in serum of hepatitis patients was examined by double monoclonal antibody sandwich ELISA. Five hybridoma cell lines were screened and named HCV(1), HCV(2), HCV(3), HCV(4), and HCV(5). These five monoclonal antibodies had high specificity and efficiency. The additivity test showed that HCV(2), HCV(4), and HCV(5) recognized different epitopes, which can be matched in ELISA. Of 173 anti-HCV positive patients, 37 (21.4%) were positive for HCV antigen. Of 1498 anti-HCV negative patients, 10 (0.67%) were positive for HCV antigen. Fifty normal controls were negative for HCV antigen. HCV antigen detection had moderate agreement and correlation with HCV RNA detection (kappa=0.577, p<0.01; r=0.59, p<0.01). This result indicates that the monoclonal antibody against HCV NS(3) may be a potential diagnostic reagent, which would provide a foundation for developing a sandwich ELISA of HCV antigen detection.

Evaluation of the dried blood spot (DBS) collection method as a tool for detection of HIV Ag/Ab, HBsAg, anti-HBs and anti-HCV in a Malaysian tertiary referral hospital

INTRODUCTION

Dried blood spot (DBS) collection is an appealing alternative to whole blood or plasma sampling, as it has technical and economic advantages over the latter.

MATERIALS AND METHODS

A prospective cross-sectional study was conducted at a Malaysian tertiary referral hospital from November 2009 to March 2010. One hundred and fifty paired specimens of DBS and plasma were analysed by the standard assays for HIV Ag/Ab, HBsAg, anti-HBS and anti-HCV, separately (total 600 paired specimens). DBS sample titres were then compared to the results of plasma testing, which was used as the gold standard.

RESULTS

For the HIV Ag/Ab assay with a cut-off point of 0.35 Relative Light Units (RLUs), the sensitivity and specificity were both 100%. For the HBsAg assay, the sensitivity was 96.5% and the specificity was 97.8%, with a cut-off point of 1.72 RLUs. Sensitivity for the anti-HBs test was 74.2% and the specificity was 86.9%, using a cut-off point of 0.635 RLUs. For the anti-HCV assay, the sensitivity was 97.3% and the specificity was 100%, with a cut-off point of 0.10 RLUs.

CONCLUSION

DBS is an ideal choice to be used as a screening tool for the detection of HIV, Hepatitis B and Hepatitis C virus infections. However, different cut-off values need to be used for the validation of test positivity in DBS samples because the small amount of blood in the DBS specimens leads to lower assay titres.

[Detection of hepatitis C core antigen in intravenous drug addictions]

OBJECTIVE

To study the status of detection of hepatitis C core antigen in intravenous drug addictions, and discuss the foreground of the hepatitis C core antigen ELISA test system.

METHODS

HCV core antigen, HCV RNA quantity, anti HCV-IgG, HBsAg were analysis in all the plasma samples taken from 93 cases of intravenous drug users.

RESULTS

The specialty and sensitivity of HCV core antigen in intravenous drug addictions 100% -54% separately. When HBsAg were positive, the sensitivity of HCV core antigen was 38%, while HBsAg negative, the sensitivity of HCV core antigen was 69% (P < 0.01).

CONCLUSION

The detections of HCV core antigen showed high specialty but low sensitivity in intravenous drug addictions. The positive rate has positive relation with HCV RNA virus logarithm quantity. Coinfection with HBV are the interfere factor of HCV core antigen detection. In screening experimentations, the detection of HCV core antigen in plasma may be applied as supplement method for anti-HCV-IgG. It can also be used to monitor viremia in HCV infection.

[Serum alpha-fetoprotein levels in pregnant women with indeterminate result of anti hepatitis C virus antibodies analysis]

AIM

Comparison of alpha-fetoprotein (AFP) levels in blood sera samples of women in the early stages of pregnancy with positive or indeterminate results of anti-HCV.

MATERIALS AND METHODS

Blood sera samples of women in the first trimester of pregnancy were analyzed by using microplate test systems for enzyme immunoassay (EIA) with complex and separate detection of antibodies against hepatitis C virus (HCV) antigens.

RESULTS

AFP levels were higher in women in the first trimester of pregnancy with anti-HCV than in women without anti-HCV. AFP levels in blood sera samples of pregnant women with indeterminate results of anti-HCV analysis were higher than in blood sera samples of pregnant women without anti-HCV. No differences in serum AFP levels were observed between anti-HCV positive samples and samples with indeterminate results of analysis.

CONCLUSION

Increased AFP level in the first trimester of pregnancy was observed not only in women with HCV infection, but also in women with indeterminate results of anti-HCV analysis. The data suggest that these groups may have epidemiological similarity.

[Frequency of hepatitis B and hepatitis C markers and HIV markers detection in blood donors from the Swietokrzyskie region]

The study analysed the occur frequency of viral hepatitis type B and type C markers and HIV markers detected in blood donors from the region Swietokrzyskie in the years 2005-2009. In analysed period 78587 blood donors were screened for viral markers: 36360 first time donors and 42227 repeat donors. All reactive results were confirmed by another test. HBV markers was detected in 0.336% of the first time donors and 0.005% of the repeat donors (2 cases of occult HBV infection - OBI). HCV markers was detected in 0.597% of the first time donors and 0.024% of the repeat donors. HIV markers was detected in 0.003% of the first time donors and 0.012% of the repeat donors. It was found that the frequency was lower than the national average.

[Epidemiologic peculiarities of infections caused by the hepatitis B and C viruses among lung tuberculosis patients]

The article presents the results of serological investigation for presence of specific markers of hepatitis B (HBV) and hepatitis C (HCV) infections in serum samples obtained from 600 patients with acute and chronic forms of lung tuberculosis (LT) and in control group I - 600 healthy adults and in control group II - 796 patients with somatic pathology from multiprofile hospital. It has been established that among LT patients frequency of revealing HBsAg and anti-HCV is statistically steady; similar indicators are among persons from both control groups. The frequency of revealing of these markers among patients with chronic forms of LT is considerably higher than frequency of their revealing in patients with acute forms of LT. At the same time, both infections in patients with LT were often presented in form of subclinical hepatitis, identified by increase in of aminotransferases activity in blood.

Evaluation of the use of a combined HCV antigen/antibody assay in routine laboratory practice

BACKGROUND

Combined hepatitis C virus (HCV) antigen/antibody (Ag/Ab) assays offer the advantage of a shorter window phase compared to traditional anti-HCV antibody assays. These assays have been extensively evaluated for the screening of healthy blood donors, but not in routine laboratory practice.

METHODS

We evaluated the performance of the combined HCV Ag/Ab assay Monolisa Ultra and compared it to Monolisa anti-HCV Plus (which only detects anti-HCV antibodies) in 61 HCV RNA-positive patients (genotypes 1 to 5) and in 276 consecutive AxSYM HCV-reactive patients. Discordant sera were tested with immunoblot and PCR.

RESULTS

All 61 PCR-positive sera were positive with AxSYM, Monolisa Ultra, and Monolisa Plus. Of the 276 consecutive AxSYM-reactive patients, 177 were confirmed as HCV-positive, 78 were HCV-negative and 21 were HCV-indeterminate. There were 4 false-positive results with Monolisa Ultra compared to 1 false-positive result with Monolisa PLus. The signal/cut-off ratio in immunoblot-negative sera was significantly higher with HCV Ultra compared to HCV Plus (p < 0.01). Sensitivity and specificity in AxSYM-reactive sera were 99.4% and 94.9% for Monolisa Ultra and 99.4% and 98.7% for Monolisa Plus.

CONCLUSION

When used as a secondary test, the sensitivity of the combined HCV Ag/Ab assay Monolisa Ultra was excellent, but specificity was reduced in AxSYM-reactive sera compared to Monolisa Plus.

[Atomic force microscopy detection of serological markers of viral hepatites B and C]

The aim of the study was to demonstrate the possibility of detection of serological markers, containing the hepatitis B surface antigen (HBsAg) and hepatitis C virus core-antigen (HCVcoreAg) in human serum, by use of a new atomic force microscopy (AFM)-based nanotechnological approach. In this study, the immobilization on AFM-chip of antibodies against the hepatitis B virus surface antigen (anti-HBsAg) as well as the antibodies against the hepatitis C virus core antigen (anti-HCVcoreAg) was performed. It was shown that such approach enables to detect: HBsAg, HCVcoreAg and the viral fragments containing these antigens in the serum. Comparative analysis of detection of HBsAg- and HCVcoreAg-containing particles by use of the AFM method vs. traditional methods (ELISA, PCR) has demonstrated the 75% coincidence of results between the AFM and the latter two methods.

[Detection of hepatitis C virus antigen in hemodialysis patients]

OBJECTIVE

To investigate the utility of the HCV core antigen ELISA in the detection of HCV infection in hemodialysis patients and to compare with Anti-HCV antibodies 3rd generation ELISA.

METHODS

Two hundred fifty hemodialysis patients were included in the study. Anti-HCV antibodies and total HCVcAg was determined by ELISA kits. HCV RNA was determined using reverse transcriptase polymerase chain reaction (RT-PCR).

RESULTS

Forty-three out of 250 (17.2%) patients were positive for anti-HCV antibodies and 18% were positive for HCVcAg. 13/250 (5.2%) were positive for HCVcAg but anti-HCV negative, All 13 were confirmed viremic by in-house nested RT-PCR leading to specificity of 100%. Viral load of (49258 +/- 28682) copies/ml were detected in HCVcAg positive cases was higher in comparison to (23938 +/- 10780) copies/ml in the anti-HCV positive group (P < 0.05). The viral load of 4 negative cases for HCVcAg assay but anti-HCV positive was 306 +/- 161 copies/ml which was significantly lower in comparison to HCVcAg positive group (P < 0.001).

CONCLUSION

Detection of total HCVcAg together with anti-HCV will be useful for patients undergoing hemodialysis who have a longer window period due to immunosuppressed state. HCVcAg was compatible for the HCV RNA in serum and total HCVcAg ELISA is both a cost-effective and a less labor-intensive alternative to PCR, enhancing its clinical utility.

Simultaneous detection of anti-HCV antibody and HCV core antigen

HCV infection is usually diagnosed by means of an enzyme immune assay for the detection of antibody against HCV. The window period between infection and seroconversion remains a dramatic problem in the transfusional and diagnostic setting. In this chapter, we report (i) procedures for assays using two different approaches designed to reduce the window period and (ii) performance in terms of specificity and sensitivity in the detection of both antibody and antigen, and we compare their efficacy with that of commercial assays.

[Rationale for the implementation of pre-operative testing for HCV in the light of anti-HCV and HBsAG tests results in surgical patients from a teaching hospital]

Many Polish hospitals compel patients admitted for elective surgery to be immunised for HBV; testing for HBsAg is recommended before. We surveyed immunisation coverage for HBV and prevalence of HBsAg and anti-HCV among surgical patients to assess existing pre-operative screening policies.

METHODS

questionnaire data and sera were collected anonymously from 400 consecutive adults admitted to 4 surgical wards of a teaching hospital in Szczecin, Poland during October 2006/December 2007. Samples were assayed for HBsAg, and anti-HCV.

RESULTS

Serologic evidence for either HBsAg or anti-HCV was 2.3% (9/400; 95% CI: 1.2-4.2%), all in elective cases; 1.5% (6/400; 95% CI: 0.7-3.2%) were positive for anti-HCV, 0.75% (3/400; 95% CI: 0.26-2.18%) for HBsAg. None of anti-HCV positive patients was aware of their infection, as well as 1 in 3 HBsAg carriers. Anti-HCV and HBsAg prevalence in 20131 blood donors which served as controls were 0.08% (95% CI: 0.02-0.15%) and 0.11% (95% CI: 0.04-0.2%) respectively. HBV immunisation coverage was 247/398 (62%), higher (p < 0.0001) in those undergoing elective rather than emergency surgery.

CONCLUSIONS

anti-HCV prevalence was double that for HBsAg. These data give evidence for the expansion of the existing screening programme for blood borne infections among elective surgical patients, to also cover those infected with HCV. A third of patients were unimmunised, remaining a potential pool for HBsAg carriers.

Partial splenic embolization reverses insulin resistance in patients with liver cirrhosis

BACKGROUND

It is well known that patients with liver cirrhosis often develop insulin resistance and diabetes mellitus. Recently, we encountered a liver cirrhosis patient in whom partial splenic embolization (PSE) improved insulin sensitivity. Therefore, we conducted further investigation about PSE and insulin resistance.

METHODS

Thirty-seven consecutive patients with liver cirrhosis underwent PSE. Hemodynamic changes, blood counts, and homeostasis model assessment of insulin resistance (HOMA-IR) were assessed before and 2 weeks after PSE.

RESULTS

PSE resulted in decreased splenic venous flow and increased intestinal venous flow to the liver. Platelet counts before and after PSE were 7.7+/-0.5 x 10(4) /microL, 15.0+/-1.4 x 10(4) /microL, respectively (p<0.01). HOMA-IR before and after PSE were 6.5+/-2.1, 3.3+/-0.6, respectively (p<0.05). HCV core antigen before and after PSE were 6,340+/-1,296 fmol/L, 4,112+/-873 fmol/L, respectively (p<0.05). Conclusion PSE significantly reverses insulin resistance in patients with liver cirrhosis. The increase in intestinal venous flow to the liver and reduced HCV viral load were thought to be mechanisms of improvement in insulin sensitivity after PSE.

HBV genome integration and genetic instability in HBsAg-negative and anti-HCV-positive hepatocellular carcinoma in Japan

The aim of this study is to clarify the existence and the form of HCV RNA and HBV DNA genome integration and genetic instability in liver tissue with HBsAg-negative and anti-HCV-positive HCC. We investigated 16 Japanese patients with HBsAg-negative and anti-HCV-positive HCC. HBV genome integration into host cell genome by Southern hybridization and PCR was examined. Moreover, we analyzed loss of heterozygosity (LOH) and replication errors (RER) of chromosomes 2p, 3p and 17p using the PCR and an autosequencer to determine the three microsatellite regions D2S123, D3S1067, TP53. Eight (50.0%) of 16 were found to have integrated genome of HBV in tumor tissue (T) by PCR. In even the non-tumor regions (NT), seven patients (43.8%) were found to have HBV genome integration. The coincidence between T and NT was found in 4 (25%). Integration of HBV-X gene in T was revealed in three (18.7%), and HBV-integration was confirmed in all NT. No integration of the X gene alone was found in the liver tissue. Five (37.5%) of eight HBV DNA integrated cases simultaneously had HCV RNA minus strand. Concerning the genetic instability, RER were detected in two of 16 (12.5%). RER at 2p; D2S123 was observed in one of 16 (6.2%) and at 3p; D3S1067 was observed in one (6.2%). LOH at the D2S123 locus was observed in one of 12 tumors with heterozygosity (8.3%). There was no genetic instability (LOH or RER) of TP53 which was p53 locus on 17p in T. There was only one case of eight HBV DNA integrated cases (6.2%) with genetic instability of RER of 3p simultaneously in T. In conclusion, the majority of HBsAg-negative and anti-HCV-positive HCC liver tissue was found to have HCV-RNA and HBV DNA integration, and in some samples, HBV DNA integration and genetic instability were concurrently confirmed. It is speculated that multistep carcinogenesis may have been proposed for HCC oncogenetic progression.

Establishment of hybrid cell lines producing monoclonal antibodies to a synthetic peptide from the E1 region of the hepatitis C virus

We aimed at establishing hybridoma cells secreting monoclonal antibodies (mAbs) against E1 synthetic peptide of HCV. BALB/c mice were immunized with HCV E1-synthetic peptide (GHRMAWDMM) and its spleenocytes were fused with the P3NS1 myeloma cell line. Two highly reactive and specific mAbs (10C7 IgG2b mAb, and 10B2 IgG1 mAb) were generated. The target HCV E1 antigen was identified at approximately 38 kDa in serum of infected individuals. A newly developed ELISA detected the target antigen in 90% of sera from HCV RNA infected individuals with a specificity of 84%. So, the generated mAbs may provide promising probes for serodiagnosis of HCV infection.

[HCV genotypes in Polish blood donors in period 1995-2007]

The results of HCV genotype distribution between 1995 and 2007 in Polish blood donors were analyzed. Special attention was drawn into the analysis of HCV polymorphism isolated from blood donors in the early phase of infection (RNA HCV positive/anti-HCV negative). Such donors identified in Poland since 2000 when the NAT for HCV was introduced are very important for molecular epidemiology analysis. The increasing frequency of 3a and 4 genotypes is observed in comparison to blood donors and patients with anti-HCV antibodies.

[Evaluation on the use of detection of hepatitis C core antigen for screening blood donor]

OBJECTIVE

To investigate the value of detection of hepatitis C virus core antigen (HCV-cAg) for screening blood donor by using the internal reagent enzyme immunoassay (EIA) and anti-HCV antibody.

METHODS

The first and repeat assays were performed for detection of serum anti-HCV and HCV-cAg ELISA in 3972 donor's serum specimens from August to October of 2004. Twenty-five donors positive for anti-HCV were tested with HCV-cAg EIA kits and the results were compared with the results of HCV RNA determination with RT-PCR method.

RESULTS

In 3972 donor's serum samples, only 1 serum specimen was positive for HCV RNA identification among 10 specimens which were positive for anti-HCV in first assays, and only 1 serum specimens was positive for HCV RNA identification among 12 specimens positive for anti-HCV in repeat assays, only 2 serum specimens were positive HCV RNA identification in 3 specimens which were positive for HCV-cAg assays.

CONCLUSION

The sensitivity of HCV-cAg ELISA is similar to HCV RT-PCR, but it is much cheaper. Therefore, HCV-cAg ELISA and anti-HCV may be used together to screen blood donor.

[Improvement of sensitivity in the second generation HCV core antigen assay by a novel concentration method using polyethylene glycol (PEG)]

A HCV core antigen (Ag) detection assay system, Lumipulse Ortho HCV Ag has been developed and is commercially available in Japan with a lower detection level limit of 50 fmol/l, which is equivalent to 20 KIU/ml in PCR quantitative assay. HCV core Ag assay has an advantage of broader dynamic range compared with PCR assay, however the sensitivity is lower than PCR. We developed a novel HCV core Ag concentration method using polyethylene glycol (PEG), which can improve the sensitivity five times better than the original assay. The reproducibility was examined by consecutive five-time measurement of HCV patients serum, in which the results of HCV core Ag original and concentrated method were 56.8 +/- 8.1 fmol/l (mean +/- SD), CV 14.2% and 322.9 +/- 45.5 fmol/l CV 14.0%, respectively. The assay results of HCV negative samples in original HCV core Ag were all 0.1 fmol/l and the results were same even in the concentration method. The results of concentration method were 5.7 times higher than original assay, which was almost equal to theoretical rate as expected. The assay results of serially diluted samples were also as same as expected data in both original and concentration assay. We confirmed that the sensitivity of HCV core Ag concentration method had almost as same sensitivity as PCR high range assay in the competitive assay study using the serially monitored samples of five HCV patients during interferon therapy. A novel concentration method using PEG in HCV core Ag assay system seems to be useful for assessing and monitoring interferon treatment for HCV.

Feasibility and cost-benefit of implementing pooled screening for HCVAg in small blood bank settings

To examine the accuracy, feasibility and benefits of screening for hepatitis C virus core antigen (HCVAg) using enzyme-linked immunosorbent assay (ELISA) test in pools. Many countries cannot afford to test blood donations for hepatitis C using molecular methods. Screening individual units using the ELISA HCVAg test is an acceptable, yet still expensive, alternative, especially for small blood bank settings. This study evaluated the option of screening for HCVAg in pools. The sensitivity (Se) and specificity (Sp) of HCVAg in pools of three and six antibody-negative samples were estimated and compared with polymerase chain reaction (PCR). The feasibility and cost-benefit of the assay was assessed on 960 routine samples collected at a hospital blood bank in Gaza. Based on results for 50 PCR-positive pools and 50 and 110 PCR-negative pools of three and six, the Se of testing in pools of three and six samples is 80-82% [95% confidence interval (CI): 66.3-91.4] and Sp >or=98% (95% CI: 89.4-100.0) compared with PCR. The incidence of antigen in donors in Gaza was 0.1% (95% CI: 0-0.56). Cost analyses suggested significant benefits from implementing screening blood donations for HCVAg when the incidence rate is >4.2/10,000, leading to reduction in the expenditures needed to treat patients infected with HCV. The risk of transfusion-transmitted hepatitis C in resource-deprived developing countries can be efficiently reduced by additional screening of antibody-negative blood donations for HCVAg in pools of six.

[Comparative analysis of hepatitis C virus core protein in the plasma and serum samples from HCV-infected blood donors and patients with hepatitis C]

The aim of the study was to develop a sensitive and specific method for revealing the direct marker of hepatitis C virus (HCV)--core protein in the serum and to test it in the laboratory setting. Experiments were made on plasma and serum samples from asymptomatic HCV-seropositive blood donors (n=65), patients with acute (AHC) and chronic (CHC) hepatitis C (n=295), and HCV-seronegative blood donors (n=20). The processing protocol for serum included their concentration by means of polyethylene glycol and subsequent treatments of pellets to detect core protein in free virions, nonenveloped nucleocapsids, and immune complexes. This allowed an assay to be developed for the detection of core protein, by using a sandwich ELISA. Inclusion of a combination of three original monoclonal antibodies into the sandwich could reveal in the samples core proteins of at least 3 genotypes of HCV (1, 2, and 3) with a sensitivity of 20 pg/ml in the majority of HCV-infected subjects. The results of determination of core protein and HCV RNA correlated with a high degree of sensitivity. To detect HCV in the blood of patients with AHC, it was shown to be sufficient to find freely circulating virions whereas an analysis of immune complexes should be included in cases of CHC to achieve more sensitivity. The findings are a basis for developing a test system for the diagnosis of hepatitis C, including its early stages before seroconversion and for determining a viral load during interferon therapy. Introduction of the method into practice increases the reliability of the diagnosis of hepatitis C and virus-free safety of blood transfusions.

[Clinical assessment of Monolisa HCV Ag-Ab ULTRA (Bio-Rad) in a general hospital]

INTRODUCTION

To evaluate a new test based on simultaneous detection of HCV antibodies and antigen (Monolisa HCV Ag/Ab ULTRA; Bio-Rad, Marnes la Coquette, France).

METHODS

We studied samples from two groups of patients and 7 commercial HCV seroconversion panels (75 samples). Group 1: 1360 serum samples from patients referred for routine testing of anti HCV antibodies. Group 2: 333 serum samples from 183 hemodialysis patients. All samples were tested by the Ortho HCV 3.0 technique (Ortho-Clinical Diagnostics, Amersham, UK) and the Monolisa HCV Ag-Ab ULTRA technique.

RESULTS

Group 1: Seventy-four of 1360 serum samples were positive by Ortho HCV and 77 by Monolisa. In 1353 samples, the results with the two tests were concordant: 1281 negative and 72 positive. Five samples were positive only by Monolisa and 2 only by Ortho (overall agreement: 99.5%). Group 2: Results were concordant in 325 samples, 308 negative and 17 positive. Seven samples were positive by Monolisa and negative by Ortho. The sensitivity of the Monolisa test in hemodialysis patients was clearly higher than that of the Ortho test (100% and 70.8%, respectively). Monolisa detected HCV infection in 43 of 75 samples from the seroconversion panels; only 18 positive samples were detected by Ortho HCV. Monolisa reduced the window period by up to 72 days.

CONCLUSIONS

Our data indicate high agreement between the Monolisa and Ortho tests in samples from the general population. In hemodialysis patients, however, Monolisa was more sensitive. In addition, the Monolisa test significantly reduced the window period of HCV infection.

Chip-based detection of hepatitis C virus using RNA aptamers that specifically bind to HCV core antigen

The development of reagents with high affinity and specificity to the antigens of hepatitis C virus (HCV) is important for the early stage diagnosis of its infection. Aptamers are short, single-stranded oligonucleotides with the ability to specifically recognize target molecules with high affinity. Herein, we report the selection of RNA aptamers that bind to the core antigen of HCV. High affinity aptamers were isolated from a 10(15) random library of 60 mer RNAs using the SELEX procedure. Importantly, the selected aptamers specifically bound to the core antigen, but not to another HCV antigen, NS5, in a protein chip-based assay. Using these aptamers, we developed an aptamer-based biosensor for HCV diagnosis and detected the core antigen from HCV infected patients' sera with good specificity. This novel aptamer-based antigen detection sensor could be applied to the early diagnosis of HCV infection.

HCV core protein immunization with Montanide/CpG elicits strong Th1/Th2 and long-lived CTL responses

An efficient vaccine against Hepatitis C virus (HCV) infection requires induction of strong humoral and cellular responses against viral proteins. We evaluated the immunogenicity of HCV core protein (HCVcp), a prime vaccine candidate, formulated in various human compatible adjuvants. An Escherichia coli-expressed HCVcp, purified in native conditions was used for murine immunization in separate groups of: free HCVcp (Ag), Ag+C/IFA (Freunds), Ag+CpG, Ag+M720 (Montanide ISA 720), Ag+F127 (Pluronic acid) and cocktails of Ag+F127+CpG and Ag+M720+CpG. Mice immunized with M720(+CpG) developed the highest HCVcp-specific titers of total IgG, IgG1, 2a, 2b, and that of IFN-gamma and IL-4 cytokines compared to all other groups. HCVcp-specific-CTLs against relevant MHC class I peptides were detected only for Ag+M720+CpG, Ag+M720, and Ag+CpG groups and could be blocked by antimouse-CD8 antibodies. While CTLs were stable, only F127 formulated groups demonstrated detectable IgG antibodies one year post-immunization. Hence, HCVcp formulated in M720 (with a synergistic effect by inclusion of CpG) could induce balanced and strong Th1/Th2 responses with long-lived CD4(-)CD8(+) CTLs.

Quantitative measurement of hepatitis C virus core antigen is affected by the presence of cryoglobulins

Mixed cryoglobulinaemia is associated strikingly with HCV infection. The aim of this study was to assess whether the adherence to proper methods of collecting samples for cryoglobulin detection was critical or not on virological parameters in hepatitis C virus (HCV) patients. We studied 56 consecutive patients. Blood samples were collected using a conventional method and a blood collection method at 37 degrees C adapted to cryoglobulin detection. HCV core antigen and HCV RNA were measured in sera and cryoglobulins issued from both blood collection methods. In cryoglobulin-positive patients, serum concentrations of HCV core antigen, but not that of HCV RNA, were significantly higher when a conventional method was used, compared to a blood collection method at 37 degrees C (P = 0.001). In the cryoprecipitates, concentration of HCV core antigen was optimum when the blood collection method at 37 degrees C, rather than the conventional method, was applied for cryoglobulin detection (P < 10(-4)). The recovery of HCV core antigen in the cryoprecipitate was improved when cryoglobulins were isolated using the blood collection method at 37 degrees C rather than the conventional method (P < 0.001). HCV parameter measurements and cryoglobulin study should not be performed on the same serum samples due to the potential impact of blood collection methods on results.

Significance of the hepatitis C virus (HCV) core antigen as an alternative plasma marker of active HCV infection

PURPOSE

To evaluate the role of core antigen (Ortho trak-C assay) as a marker of active HCV infection in comparison to HCV RNA as detected by reverse transcription polymerase chain reaction (RT-PCR).

METHODS

This evaluation was carried out during January 2000 to December 2003 in HCV infected individuals who were treatment naomicronve or were on anti-viral therapy. Additionally, sequential plasma samples from patients on clinical follow-up were included in this study. A total of 167 samples from 61 patients were tested by trak-C and RT-PCR. HCV RNA detection was achieved by a RT-PCR. Trak-C assay results were also compared in a limited proportion of these samples with known HCV viral load and genotype.

RESULTS

Of 167 samples tested, 56.9% were RNA positive and 43.1% were RNA negative while 50.3% were trak-C positive and 49.7% were trak-C negative, yielding a sensitivity of 85.3% and a specificity of 95.8% for the trak-C assay (Kappa co-efficient = 0.8). The concentration of HCVcAg and HCV RNA showed significant correlation (n=38, r=0.334, P =0.04). The trak-C assay detected the most prevalent HCV genotypes in India without significant difference (P =0.335). The difference between mean absorbance values of HCV RNA positive samples compared to HCV RNA negative samples in the trak-C assay was highly significant (P < 0.000). Qualitative results of trak-C assay and RT-PCR were comparable in 93% of follow-up samples.

CONCLUSIONS

Trak-C assay can be recommended for confirmation of HCV infection and follow-up in laboratories with resource-poor facilities.

Value of HCV antigen-antibody combined HCV assay in hepatitis C diagnosis

Reduction of the window period of hepatitis C virus (HCV) infection represents an important goal in the transfusional and diagnostic settings. Currently, the detection of HCV infection relies on the use of immunoassays to detect viral antibodies. A new enzyme immunoassay (Monolisa HCV Ag-Ab ULTRA) designed to simultaneously detect circulating HCV antigen and anti-HCV antibodies has been developed by Bio-Rad and registered by the European Authorities. Several evaluations have been conducted in Europe to determine whether this new assay can improve early detection of HCV infection. Sensitivity studies included 130 HCV RNA positive/anti-HCV negative samples, 21 well documented seroconversion panels and 430 anti-HCV genotyped samples from France and Italy. Specificity has also been assessed in 15,302 non-selected blood donations and hospital samples. Studies have shown that Monolisa HCV Ag-Ab ULTRA assay has been able to detect 40-90 % of HCV RNA positive/anti-HCV negative samples collected in the window period, improving early detection of HCV when antibodies may be undetectable. The mean delay in detecting HCV infection between HCV-RNA and this new test was found to be 5 days, reducing the window period by an average of 37 days. All samples collected after seroconversion were detected with the HCV Ag-Ab ULTRA assay. The specificity analyzed in 15,302 random blood donations and hospital samples was estimated at 99.86 %. Although less sensitive than NAT (71 % of HCV RNA positive/anti-HCV negative in window period), this assay could be a reasonable alternative when NAT cannot be used for reasons such as cost, organization, emergency or logistic difficulties.

Direct evidence for immunomodulatory properties of ribavirin on T-cell reactivity to hepatitis C virus

BACKGROUND/AIM

An understanding of ribavirin's beneficial effects on treatment outcome in chronic hepatitis C (CH-C) may help to develop new treatment approaches. Here we investigated whether ribavirin directly affects HCV-specific reactivity of CD4+T-lymphocytes from patients with CH-C.

METHODS

Peripheral blood mononuclear cells from forty HCV RNA positive patients were cultured ex vivo with HCV core, NS3, NS4 alone, and with different concentrations of ribavirin. Virus-specific CD4+ T-cell reactivity was analysed by a proliferation assay; quantitation of cytokine (interferon-gamma, IL-10, IL-5, IL-12p35, IL-12p40) mRNA levels; measurement of interferon-gamma and IL-10 production (by ELISA) and enumeration of interferon-gamma and IL-10 producing T-cells by Elispot assays.

RESULTS

At 2-5 microM ribavirin induced de novo or enhanced T-cell proliferation to HCV antigens in a proportion of patients. Increased T-cell proliferation was associated with decreased IL-10 production in response to HCV core and reduced frequency of IL-10 producing CD4+ T-cells, while interferon-gamma levels remained unchanged. At 20 microM ribavirin markedly suppressed T-cell proliferation, and interferon-gamma mRNA expression to HCV antigens.

CONCLUSIONS

Ribavirin, at clinically achievable plasma levels, modulates directly the T-cell responses to HCV antigens in some CH-C patients. Suppression of IL-10 production may represent a useful strategy to induce/augment T-cell reactivity to HCV.

A chemiluminescent, magnetic particle-based immunoassay for the detection of hepatitis C virus core antigen in human serum or plasma

Hepatitis C virus (HCV) exposure in blood donors is determined serologically by the detection of anti-HCV antibodies in serum or plasma. However, a "window" period of 30-70 days after exposure exists where specific antibodies to HCV antigens are not detected. The use of nucleic acid testing for the detection of HCV RNA or antigen testing for the detection of HCV core protein have resulted in dramatic reductions in the pre-seroconversion window period. In this study, an automated HCV core antigen detection test was developed. This magnetic microparticle-based assay utilizes anti-HCV core monoclonal antibody to capture antigen present in human serum or plasma. Captured antigen is then detected using an anti-HCV core monoclonal antibody conjugated with a chemiluminescent compound. The specificity of this assay was established at 99% upon testing a population of normal volunteer blood donors. Sensitivity was determined by testing 16 commercially available HCV seroconversion panels representing genotypes 1a, 1b, 2b, and 3a. In each panel tested, HCV core antigen was detected prior to anti-HCV antibody, resulting in a reduction of the window period by greater than 23 days on average, and greater than 34 days on panels initially NAT negative. In addition, HCV core antigen was detected in >97% of HCV RNA positive/antibody negative specimens, exhibiting sensitivity nearly equivalent to nucleic acid testing in the pre-seroconversion window period for the panels examined.

[Antigenicity of hepatitis C virus F protein and serum prevalence of anti-F in HCV-infected patients]

OBJECTIVE

To examine the antigenicity of hepatitis C virus (HCV) F protein and investigate serum prevalence of anti-F in HCV-infected patients.

METHODS

Eleven pairs of overlapping primers were used to synthesize the full-length HCV f gene, from which the truncated HCV f65 gene fragment was amplified by PCR. HCV f65 gene was then cloned into pET32a(+), and transformed into E. coli strain Plyss (DE3). This recombinant E.coli was induced by IPTG for the production of HCV F65 protein. The expressed HCV F65 protein, purified by Ni-NTA agarose, was further used in ELISA to detect serum anti-F, and to immunize rabbits for making polyclonal anti-F. The rabbit polyclonal anti-F was purified by Staphylococcus aureus protein A agarose.

RESULTS

After recombinant pET32a(+)-f65 was constructed successfully, HCV F65 protein was expressed and purified. The purified HCV F65 protein was used as a capture antigen in ELISA to detect serum anti-F in HCV infected patients (n = 30). The result showed that the mean A450 value and the positive rate of serum anti-F were 0.125+/-0.061 and 63.3%, respectively. The rabbit-derived polyclonal anti-F reacted specifically with HCV F65 protein, of which the titer was 1:30,000.

CONCLUSION

Our expressed HCV F65 protein is of antigenicity, and can be used to determine serum anti-F. Anti-F IgG does exist in the sera of the HCV-infected patients. Moreover, the rabbit-derived polyclonal anti-F can be used to detect HCV F protein.

[Qualitative detection of hepatitis C virus core antigen in the serum in patients with chronic hepatitis C]

OBJECTIVE

To evaluate the clinical significance of serum hepatitis C virus (HCV) core antigen detected by enzyme linked immunosorbent assay (ELISA).

METHODS

The serum HCV core antigen, which was taken from 149 patients with chronic hepatitis C, 20 patients of chronic hepatitis B and 20 health volunteers, was detected by ELISA. Meanwhile, the serum HCV RNA was detected by RT-PCR, and anti-HCV was detected by ELISA.

RESULTS

The qualitative HCV core antigen in the serum, which was take from 20 patients of chronic hepatitis B and 20 health volunteers, was negative.The positive percentage of HCV core antigen was 49.66% in the 149 sera of patients with chronic hepatitis C. The coincidence of detective results of HCV RNA and HCV core antigen was 54.36%, without significant difference (P>0.05). The positive percentage of HCV RNA and HCV core antigen in the 149 anti-HCV antibody positive sera samples were 55.03% (82/149) and 49.66% (74/149), respectively, and there was no significant difference (P>0.05).

CONCLUSION

The qualitative HCV core antigen detected by ELISA has a high specificity. The positive percentage of HCV core antigen in the serum of patients with chronic hepatitis C is 49.66%. HCV core antigen is related to HCV RNA. HCV core antigen may be a useful serum marker which could show HCV viraemia like HCV RNA.

Combined hepatitis C virus (HCV) antigen-antibody detection assay does not improve diagnosis for seronegative individuals with occult HCV infection

A combined hepatitis C virus (HCV) antigen-antibody assay was evaluated for 115 seronegative individuals with occult HCV infection. The assay was reactive in one patient and negative to weakly reactive in three others (all four gave indeterminate results by supplemental assay) but failed to detect HCV in the remaining patients. Despite increased sensitivity the combined assay does not improve serodiagnosis of occult HCV infection.

Reliability and diagnostic use of a test for the search of the hepatitis C virus Ag (AgHCV)

BACKGROUND/AIMS

The detection of serum HCV nucleocapsid (core) antigen, besides being a valid alternative, by virtue of its low cost, to direct analysis of the virus in everyday transfusion practice, also aims to be employed in monitoring patients subjected to antiviral therapy. The verification of strict correlation between the two tests is the presupposition for such use.

METHODOLOGY

In a group of 112 HCV-positive subjects, we assessed blood transaminases, viremia (by PCR), and the circulating core antigen (by ELISA).

RESULTS

Only 16 out of 112 patients were AgHCV-negative, with viremia levels in the 10(2) to 10(4) range; 96 patients were HCV-positive, as indicated both by viremia and by Ag detection (1.9 to 292.4pg/mL). Sensitivity of the ELISA test corresponds to 3.6x10(4) IU/mL of viral load. There is an evident aggregation of results in groups according to antigenemia classes and the corresponding viremia levels: <10pg/mL--10(4) IU/mL (6/96); up to 100pg/mL--10(5) IU/mL (55/96); 100-200pg/mL--10(6) IU/mL (31/96); and more than 200pg/mL--10(7) IU/mL (4/96).

CONCLUSIONS

AgHCV is correlated with elevation of ALT and high or medium-high viral loads. It can discriminate between ongoing and previous infection and is suitable for monitoring the pharmacological therapy in the presence of sufficiently high viral loads and for evaluating the onset of medium-long-term relapses. Neither the genotypes nor pharmacological therapy appear to affect the comparison of viremia with antigenemia. Moreover, this analysis is cheaper as compared with molecular techniques.

[Technique of detection of hepatitis C core antigen used in safety blood transfusion]

This study was purposed to investigate the feasibility to screen donor with HCV infection by means of HCV-cAg ELISA. The first and repeat assays were performed for detection of serum anti-HCV in 8677 donor's serum specimens from January 2003 to December 2005. All serum anti-HCV specimens with positive anti-HCV from first and repeat assays were finally identified by using HCV-cAg ELISA and HCV RT-PCR methods. The results showed that only 5 serum specimens were positive anti-HCV by HCV-cAg ELISA identification in 29 specimens including 15 specimens with positive ant-HCV in first assays and 14 specimens with positive anti-HCV in repeat assays, the positive rate detected by HCV cAg ELISA was 17.24%. 5 serum specimens were positive anti-HCV by HCV RT-PCR detection also in 29 specimens mentioned above, the positive rate detected by HCV RT-PCR was 17.24% too. It is concluded that sensitivity of HCVcAg ELISA is similar to HCV RT-PCR and may be useful for the early diagnosis of hepatitic C or used as a reliable method to screen donor with HCV infection in blood transfusion medicine.