Hepatitis C virus diagnosis and testing.

Liver transplantation for hepatitis C virus (HCV) non-viremic recipients with HCV viremic donors.

EASL Clinical Practice Guidelines: Management of hepatitis C virus infection

HCV Can and Should Be Eliminated From Dialysis Units

The clinical manifestations of hepatitis C virus (HCV) infection are generally indistinguishable from other causes of viral hepatitis. HCV infections are usually anicteric, asymptomatic, and rarely cause acute fulminant liver failure. Serological testing for HCV in conjunction with epidemiological studies have verified that HCV was the major cause of parenterally transmitted non-A, non-B hepatitis (NANBH). With the widespread introduction of serological screening of blood products for HCV antibody, the risk of transfusion-associated HCV infection has been dramatically reduced (to < 3 cases per 10,000 units transfused). Despite the virtual elimination of transfusion-associated infections, the diagnosis of HCV remains important because > 50% of infections are sporadic in origin, 50 to 70% of infected individuals develop chronic hepatitis, and these individuals are at risk of developing cirrhosis (> 20%) as well as hepatocellular carcinoma. Although currently available anti-HCV immunoassays function well as blood-donor screening assays, they are poor at detecting acute infection because of the prolonged lag time between infection and detection of seroconversion (approximately 10 to 26 weeks for second-generation immunoassays). In contrast, polymerase chain reaction (PCR)-based detection of HCV RNA in serum can detect infection in as little as 1 to 2 weeks after exposure. This review focuses on the impact of modern serologic and nucleic acid-based HCV detection methodology on the clinical understanding of HCV infection, its associated illnesses, and its transmissability. Quantitative and reproducible nucleic acid-based detection assays will be required to provide additional insights into the clinical spectrum of HCV infections as well as to assess the efficacy of antiviral agents.

At Japanese Red Cross (JRC) Blood Centers, all donated blood is screened for hepatitis C virus (HCV) by serological and nucleic acid amplification testing. Donor plasma that tested reactive for anti-HCV by serological test is disqualified even if the donor tests negative for HCV RNA. These test results reflect both true-positive results because of past HCV infection and false-positive results because the cross-reactivity of plasma IgG, which current testing methods are unable to distinguish. To characterize these antibody test results, we examined the neutralizing activity of these plasma samples. Donor plasma samples that tested reactive for anti-HCV by serological test but negative for HCV RNA (n = 43) were analysed for determining their neutralizing activities measured by the inhibition of the cellular entry of pseudoparticles harbouring HCV envelope glycoproteins (HCVpp). Strong and broad neutralizing activities against HCVpp entry similar to the samples that tested reactive for anti-HCV serological test and positive for HCV RNA (considered to be derived from individuals with chronic HCV infection) were observed in three of 43 plasma samples from donors who tested anti-HCV reactive but HCV RNA negative. By examining the neutralizing activities of plasma samples, we identified individuals with a past HCV infection from those in whom we were unable to confirm HCV infection according to the current testing algorithms of JRC, which do not perform anti-HCV confirmatory tests.

Logistics and cost of nucleic acid amplification testing (NAT) screening preclude its current use in many developing countries. Development of hepatitis C virus (HCV) core antigen assays offer an alternative to NAT. We evaluated two specimen populations to assess the sensitivity, relative to NAT, of the HCV core antigen (HCVcAg) ELISA (enzyme-linked immunosorbent assay) test system and the trak-C assay: (1) plasma donor HCV NAT-conversion panels and (2) cross-sectional whole blood donor NAT yield specimens. Differential sensitivities among NAT (NGI; Chiron/Gen-Probe) and both HCVcAg assays (Ortho-Clinical Diagnostics, Rochester, NY) were evaluated using: (1) 102 serial ramp-up phase specimens from 37 plasma donor NAT-conversion panels (Alpha Therapeutic/BioClinical Partners); and (2) 42 cross-sectional whole blood donor NAT yield specimens (confirmed RNA positive, antibody negative) plus 54 NAT false-positive specimens (American Red Cross). Viral load among the plasma donor NAT-conversion panels at the cutoffs for HCVcAg and trak-C assays were 32 000 copies/ml (95% confidence interval [CI] 8000-120 000) and 8000 copies/ml (95% CI: 2200-28 000), respectively. The mean (95% CI) difference in window period reduction compared to routine mini-pool NAT screening (estimated sensitivity 100 copies/ml) was delayed 5.2 days (2.2-7.6 days) for HCVcAg assay and 3.8 days (2.1-5.5 days) for the trak-C assay. Among the 42 NAT yield specimens, the HCVcAg assay detected 31 (74%) as core antigen-positive while the trak-C assay detected 37 (88%) as core antigen-positive. Viral loads for the five specimens not detected by the trak-C HCVcAg assay ranged from 100 to 7770 copies/ml. All 54 NAT false-positive specimens were non-reactive on both HCV core antigen assays. These data indicate that the trak-C assay has sensitivity approaching routine mini-pool NAT screening for the detection of seronegative HCV infection. In the absence of routine NAT screening for early HCV infection, the use of an HCV core antigen assay should be considered.

Diagnosis and monitoring of HCV infection using the cobas® HCV test for use on the cobas® 6800/8800 systems

BACKGROUND: Chronic kidney disease (CKD) is an important and noteworthy health issue worldwide. It is especially a problem in Taiwan because of its high prevalence and incidence. Although previous studies suggested that hepatitis C virus (HCV) infections may lead to nephropathy, the effect of hepatitis C on renal function in Taiwanese adults is still not well understood.METHODS: From January 2002 to December 2006, we conducted a community-based medical screening program with 22,649 participants in Chiayi County, which is endemic for HCV infection. In this study, hepatitis B virus (HBV) and HCV infection were defined as a seropositive test result for hepatitis B surface antigen and HCV antibody. Advanced CKD was defined as estimated glomerular filtration rates (eGFR) lower than 60 mL/min per 1.73 m^2 , where eGFR was computed using the four-variable Modification of Diet in Renal Disease (MDRD) Study equation. Proteinuria was defined as the presence of urine protein of at least grade 1+. Age, gender, body mass index (BMI), systolic blood pressure (SBP), fasting plasma glucose (FPG), total cholesterol (T-chol), triglyceride (TG) were considered as potential confounders.RESULTS: The mean age of the study group was 59.3 years. Prevalence of HCV infection alone, HBV infection alone, HBV/HCV coinfection, and neither were 11.95%, 11.89%, 1.66%, and 74.49%, respectively. After a series of multivariate logistic regression analyses, we found that HCV infection was an independent risk factor for advanced CKD (OR, 1.111; P ＜ 0.05) and proteinuria (OR, 1.163; P ＜ 0.05). In addition, the prevalence of HCV seropositivity was higher in later CKD stages, changing from 15.8% in CKD stage IIIa to 22.7% in CKD stage I V.CONCLUSION: HCV infection was associated with an increased prevalence of advanced CKD and proteinuria in Taiwan, which is an area endemic for HCV and CKD.

Recent experimental and epidemiological findings suggest that infectious agents may play a role in the development and progression of atherosclerosis. We previously reported that Chlamydia pneumoniae (C. pneumoniae) infection reduces the effectiveness of lipid-lowering therapy for carotid atherosclerosis and that this micro-organism may play a role in the progression of atherosclerosis. In this study, we investigated the possible association between hepatitis C virus (HCV) infection and carotid arteriosclerosis. A total of 165 asymptomatic hypercholesterolemic patients were randomized to receive probucol (500 mg/day, n=82) or pravastatin (10 mg/day, n=83) and were followed for 2 years. The 2-year change of the maximum common carotid artery intima-media thickness (Max-IMT) was the primary endpoint, while the Max-IMT and the incidence of major cardiovascular events were secondary endpoint. All serum samples were tested for antibody to HCV (anti-HCV) by enzyme-linked immunosorbent assay (ELISA), and all anti-HCV-positive samples were assayed for HCV RNA. Patients without HCV infection (n=25) showed a significant reduction of Max-IMT (-10.9%) (p<0.0001), while a small decrease of Max-IMT was noted in the patients with HCV infection (n=25) (-0. 3%). Significant differences in the reduction of serum total cholesterol and LDL cholesterol were found between patients with and without HCV infection (both p<0.0001). No significant difference in therapeutic effect was noted between the probucol and the pravastatin groups. After adjustment for confounding risk factors, both C. pneumoniae infection and anti-HCV positivity were associated with a greater risk of an increase in Max-IMT (8.5635 [1.3738-15.7532], p<0.05, 9.5040 [0.2886-18.7194], p<0.05, respectively). These findings suggest that both chronic HCV infection and C. pneumoniae infection can reduce the effectiveness of lipid-lowering therapy for carotid atherosclerosis, and that the HCV may play a role in the progression of atherosclerosis in HCV infected patients.

Hepatitis C virus (HCV) represents a viral pandemic that is five times as widespread as human immunodeficiency virus. Blood transfusion posed a major risk of HCV infection in developed countries before 1990, but the introduction of improved blood-screening measures has decreased the risk of transfusion-associated HCV infection, which may now be even lower since the introduction of screening of pooled samples by nucleic acid testing (NAT). Unfortunately, NAT is not affordable in most developing countries. The goal of this work is to assess the usefulness of both screening measures, the medical history, and the self-exclusion form to distinguish between high-risk and low-risk populations of HCV-carrier blood-donor candidates in Mexico. From February 2002 to April 2003, 4174 consecutive candidates were enrolled in a prospective, nonrandomized and comparative study. In total, 4158 candidates were included in the analysis and divided in two groups: Group A consisted of 3101 accepted donors and Group B consisted of 1057 deferred donors according to a complete medical history and self-exclusion form. The only exclusion criteria was the lack of a signed consent form to enter the study. All candidates from both groups underwent anti-HCV detection by third-generation enzyme immunoassay (EIA). Those who had either a positive or gray-zone signal-to-cutoff ratio underwent polymerase chain reaction and a second EIA test. If the second EIA test resulted in either a positive or gray-zone signal-to-cutoff ratio, a recombinant immunoblot assay test was performed. The chi-square test was used for statistical analysis, and a p value less than 0.05 was considered significant. Anti-HCV prevalence by the EIA method was as follows: 0.61 percent for Group A and 1.32 percent for Group B (p = 0.0243); whereas with recombinant immunoblot assay the prevalence was 0.19 percent for Group A and 0.47 percent for Group B (p = 0.1265). When we analyzed the polymerase chain reaction test results, the prevalence in Group A was 0.10 percent (95% confidence interval, 0.089-0.110) and in Group B was 0.47 percent (95% confidence interval, 0.439-0.500) (p = 0.0159). The medical history of blood donors in conjunction with serologic screening tests helps to improve blood transfusion safety. This measure is recommended in blood banks of those countries where NAT is still unaffordable.

Robust, polyfunctional CD8+ T-cell responses targeted to multiple viral epitopes have been associated with successful resolution of acute HCV infection. In most individuals, however, immunity fails and chronic viremia ensues as CD8+ T cells become functionally exhausted or select viral variants with escape mutations in class I epitopes. During pregnancy, dysfunctional HCV-specific CD8+ T-cell responses may be further impaired by maternal–fetal tolerance processes such as the expansion of regulatory T-cell populations or hormonal changes. Recent evidence suggests that HCV adapts to relaxed maternal CD8+ T-cell pressure in pregnancy by shedding unfit escape mutations in certain class I epitopes, resulting in the selection of viruses with more efficient replication. Emergence of HCV variants with enhanced replicative capacity during pregnancy has ramifications for mother-to-child transmission, the primary route of HCV infection in children, and could potentially be relevant to other important, vertically transmissible, persistent viruses such as HBV and HIV. HCV has infected over 185 million people worldwide and persists in approximately 75% of these individuals, predisposing to liver inflammation, cirrhosis and hepatocellular carcinoma [1]. More than 1 million children are born to HCV-infected mothers each year, and 3–5% acquire the infection in utero or at delivery, making vertical transmission the leading route of pediatric HCV infection in the developed world [2]. Here, we review the critical role of CD8+ T-cell immunity in HCV infection, its modulation in pregnancy and recent evidence that HCV takes advantage of the unique immunologic niche of pregnancy to improve replicative fitness and potentially promote vertical transmission.

Cytokines and liver injury in chronic HCV genotype 4 infection

The clinical and epidemiological relevance of circulating antibodies to hepatitis C virus (HCV) in hemodialysis patients is uncertain, since clinical signs of infection are often mild or absent, with alanine aminotransferase (ALT) values that are virtually always normal, and liver biopsies are only rarely performed. Determination of HCV RNA in serum is therefore critical for distinguishing chronic HCV infection from previous exposure to the virus. We studied HCV viremia by reverse transcription polymerase chain reaction (RT-PCR) in the 5'-noncoding region of the viral genome in 77 dialysis patients who were screened for anti-HCV by a second-generation enzyme-linked immunosorbent assay (the enzyme immunoassay II; Ortho HCV, 2nd generation, Ortho Diagnostic Systems Raritan, N.J.) and a second-generation recombinant immunoblot assay (Chiron Corporation and Ortho Diagnostic Systems) and prospectively evaluated for ALT elevations over a period of 5 years. Of 77 patients tested, 29 (38%) had active infection as shown by a positive PCR assay result, and of these, 26 were anti-HCV positive. Although a good correlation was found between circulating anti-HCV and HCV RNA in serum, 10 (28%) of 36 anti-HCV-positive patients were HCV RNA negative by PCR, suggesting either low levels of viremia or past exposure to HCV and subsequent recovery. On the other hand, 3 (7.3%) of 41 anti-HCV-negative patients had HCV RNA in their sera, indicating seronegative HCV infection. The ALT level had no predictive value for HCV infection, because it was repeatedly normal in 18 (62%) of 29 viremic patients. HCV genotyping was also performed and indicated that all four known genotypes of HCV were present in our group. In conclusion, serological assays are reliable for detecting exposure to HCV in hemodialysis patients; however, direct identification of the viral genome is required to document current infection.

A Novel Immunocompetent Rat Model of HCV Infection and Hepatitis

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