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Large-scale head-to-head assessment of the performance of lateral-flow tests (LFTs) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigen is required in the context of the continuous emergence of new viral variants. The aim of this study was to evaluate the performance of 22 rapid LFTs for the detection of SARS-CoV-2 antigens. The clinical performance of 22 LFTs was evaluated in 1,157 samples collected in the Greater Paris area. The 8 best-performing LFTs were further assessed for their ability to detect 4 variants of concern (VOC), including the alpha, beta, delta, and omicron (BA.1) variants. The specificity of SARS-CoV-2 LFTs was generally high (100% for 15 of them) but was insufficient (75%) for 3 tests. Sensitivity of the LFTs varied from 30.0% to 79.7% compared to nucleic acid amplification testing (NAAT). Using a cycle threshold (

We describe persistent circulation of SARS-CoV-2 Alpha variant in an immunosuppressed patient in France during February 2022. The virus had a new pattern of mutation accumulation. The ongoing circulation of previous variants of concern could lead to reemergence of variants with the potential to propagate future waves of infection.

The International Liver Association recommends the use of accurate and sensitive molecular methods for determination of hepatitis B virus (HBV) DNA levels in plasma or serum of chronic HBsAg carriers. The level of HBV replication represents the strongest predictive biomarker associated with disease progression and long-term outcome of chronic HBV infection. The purpose of this study was to evaluate the ability to the new Alinity m System to detect and quantify HBV DNA in plasma and whole blood collected on dried blood spots (DBS). Paired plasma and DBS samples from patients chronically infected with various HBV genotypes were tested in parallel for HBV DNA detection and quantification. There is a linear relationship between HBV DNA levels measured in plasma samples using the Alinity m HBV assay and the Xpert HBV viral load assay, used for comparison. A slight deviation (0.03 ± 0.31 log IU/mL) was observed within the quantitative range. In DBS, HBV DNA levels closely correlated with levels measured in plasma. All patients had detectable and quantifiable HBV DNA by DBS testing, except for one patient with a plasma HBV DNA level above 2,000 IU/mL. In conclusion, the newly developed real-time PCR-based assay Alinity m HBV assay can correctly detect HBV DNA in DBS, especially for patients with blood HBV DNA levels above 2,000 IU/mL, and also accurately quantify HBV DNA in plasma samples.

Background Direct detection of SARS-CoV-2 viral proteins in nasopharyngeal swabs using lateral flow immunoassays is a simple, fast and cheap approach to diagnose the infection. Aims and Methods The performance of 6 SARS-CoV-2 antigen rapid diagnostic tests has been assessed in 634 hospitalized patients or outpatients including 297 patients found to be positive for SARS-CoV-2 RNA by means of RT-PCR and 337 patients presumed to be SARS-CoV-2 RNA-negative. Results The specificity of SARS-CoV-2 RDTs was generally high (398.5%). One assay had a lower specificity of 93.2%. The overall sensitivity of the 6 RDTs was variable, from 32.3% to 61.7%. Sensitivity correlated with the delay of sampling after the onset of symptoms and the viral load estimated by the Ct value in RT-PCR. Four out of 6 RDTs tested achieved sensitivities 380% when clinical specimens were collected during the first 3 days following symptom onset or with a Ct value ≤25. Conclusions The present study shows that SARS-CoV-2 antigen can be easily and reliably detected by RDTs. These tests are easy and rapid to perform. However, the specificity and sensitivity of COVID-19 antigen RDTs may widely vary across different tests and must therefore be carefully evaluated before releasing these assays for realworld applications.

We report an outbreak of severe acute respiratory syndrome coronavirus 2 501Y.V2 in a nursing home. All nonvaccinated residents (5/5) versus half of those vaccinated with BNT162b2 (13/26) were infected. Two of 13 vaccinated versus 4 of 5 nonvaccinated residents presented severe disease. BNT162b2 did not prevent the outbreak, but reduced transmission and disease severity.

Immunocompromised individuals generally fail to mount efficacious immune humoral responses following vaccination. The emergence of SARS-CoV-2 variants of concern has raised the question as to whether levels of anti-spike protein antibodies achieved after two or three doses of the vaccine efficiently protect against breakthrough infection in the context of immune suppression. We used a fluorescence-based neutralization assay to test the sensitivity of SARS-CoV-2 variants (ancestral variant, Beta, Delta, and Omicron BA.1) to the neutralizing response induced by vaccination in highly immunosuppressed allogeneic HSCT recipients, tested after two and three doses of the BNT162b2 vaccine. We show that neutralizing antibody responses to the Beta and Delta variants in most immunocompromised HSCT recipients increased after three vaccine doses up to values similar to those observed in twice-vaccinated healthy adults and were significantly lower against Omicron BA.1. Overall, neutralization titers correlated with the amount of anti-S-RBD antibodies measured by means of enzyme immunoassay, indicating that commercially available assays can be used to quantify the anti-S-RBD antibody response as a reliable surrogate marker of humoral immune protection in both immunocompetent and immunocompromised individuals. Our findings support the recommendation of additional early vaccine doses as a booster of humoral neutralizing activity against emerging variants, in HSCT immunocompromised patients. In the context of Omicron circulation, it further emphasizes the need for reinforcement of preventive measures including the administration of monoclonal antibodies in this high-risk population.

Hepatitis C virus (HCV) genotype 4 is highly heterogeneous. HCV subtype 4r has been suggested to be less responsive to direct-acting antiviral (DAA) drug treatment than other genotype 4 subtypes. Among 537 DAA-treated patients who experienced a virological failure (VF) in France between 2015 and 2018, 121 (22.5%) were infected with genotype 4 and 27 of them (22.3%) with subtype 4r; subtype 4r was thus over-represented as compared to its prevalence in the French general population. Population sequencing of the nonstructural protein (NS) 3, NS5A, and NS5B genes was performed in all subtype 4r patients at treatment failure and in 6 at baseline, whereas full-length HCV genome sequencing was performed in two baseline and three treatment failure samples by means of an original shotgun metagenomics method based on deep sequencing. At treatment failure, all subtype 4r patients harbored two to three dominant NS5A resistance-associated substitutions (RASs), including at least L28A/C/I/M/V and L30R. Among 13 patients exposed to sofosbuvir and an NS5A inhibitor (daclatasvir, ledipasvir, or velpatasvir), 5 (38.5%) also harbored NS5B S282C/T RASs at treatment failure. An additional patient harbored S282C/T RASs at treatment failure by deep sequencing. Prevalence of S282C/T RASs at treatment failure was significantly higher in patients infected with genotype 4r than with other genotypes, including other subtypes of genotype 4. Conclusion: The lower rates of sustained virological response in patients infected with subtype 4r are related to the frequent preexistence at treatment baseline and subsequent selection by DAA treatment of both NS5A and NS5B S282 RASs. Our study suggests that these patients should be identified and receive a triple DAA combination regimen as first-line treatment.

Nucleoside and nucleotide analogues (NUCs) targeting hepatitis B virus are capable of selecting resistant viruses upon long-term administration as monotherapies. The prevalence of resistance-associated substitutions (RASs) and fitness-associated substitutions at baseline of NUC therapy and their impact on treatment responses remain unknown. A total of 232 treatment-naïve patients chronically infected with hepatitis B virus (HBV) consecutively referred for the first time to one of French reference centres were included. The nearly full-length HBV reverse transcriptase was sequenced by means of deep sequencing, and the sequences were analysed. RASs were detected in 25% of treatment-naïve patients, generally representing low proportions of the viral quasispecies. All amino acid positions known to be associated with HBV resistance to currently approved NUCs or with increased fitness of resistant variants were affected, except position 80. RASs at positions involved in lamivudine, telbivudine and adefovir resistance were the most frequently detected. All patients with RASs detectable by next-generation sequencing at baseline who were treatment-eligible and treated with currently recommended drugs achieved a virological response. The presence of pre-existing HBV RASs has no impact on the outcome of therapy if potent drugs with a high barrier to resistance are used.

Background International liver society guidelines recommended to perform HCV resistance testing at baseline of first-line therapy with certain combination regimens or prior to retreatment in patients previously exposed to a direct-acting antiviral (DAA) containing regimen. Currently, no standardized assays have been developed as purchasable kits for HCV resistance testing. The aim of this study was to evaluate the performance of the Sentosa SQ HCV Genotyping Assay, a novel deep sequencing-based assay, to identify resistance-associated substitutions (RASs) in the NS3 protease, NS5A protein domain I and NS5B polymerase regions for patients infected with HCV genotypes-1a and 1b. Methods Serum samples collected from patients with chronic hepatitis C infection who failed to achieve a sustained virological response after receiving a DAA-containing treatment regimen were extracted and sequenced by two methods including population sequencing of the NS3, NS5A and NS5B coding region reference method and the deep sequencing-based Sentosa SQ HCV Genotyping Assay. Results A high concordance rate with Sanger sequencing, the reference method, was found for the NS3, NS5A and NS5 coding regions, regardless of the genotype-1 subtypes. The deep sequencing-based assay was more sensitive than population sequencing to detect minority variants, representing less than 10% of the viral populations, but also some variants representing up to 30% of the viral quasispecies, as expected. Conclusions The Sentosa SQ HCV Genotyping Assay can be confidently used in clinical practice in the indications of HCV resistance testing for these subtypes. Technical improvements are now required to allow for pangenotypic coverage.

Direct detection of SARS-CoV-2 viral antigens could replace RT-PCR, provided that its clinical performance is validated in different epidemiological settings. Here, we evaluated the performance of the VITROS Antigen test, an enzyme immunoassay detecting a SARS-CoV-2 antigen, in NPSs from 3 cohorts of patients. Methods . Three cohorts including SARS-CoV-2 RNA-positive samples collected during the first and second wave of the French epidemic between March 2020 and February 2021 (including variant B.1.1.7/α and variant B.1.351/β). Results . Among the 1763 prospectively tested subjects, 8.2% (145/1763) were SARS-CoV-2 RNA-positive by RT-PCR. Using Ct ≤30 and Ct ≤35 as thresholds, the sensitivities of the antigen assay were 98.8% (93.6-100%) and 93.5% (87.0-97.3%), respectively. The overall specificity of the assay was 100% (1614/1614; 99.8-100%). In a retrospective cohort of subjects infected with variants of concern, 90.4% (47/52) of NPSs containing B. B.1.1.7/α (Ct ≤35) and 100% (7/7) of those containing B.1.351/β were positive with the VITROS EIA SARS-CoV-2 Antigen test. Conclusion . The excellent performance of the EIA Antigen test reported here, including in patients infected with viral “variants of concern”, support the use of high-throughput, EIA-based SARS-CoV-2 antigen assays as an alternative or complement to nucleic acid testing in order to scale-up laboratory screening and diagnostic capacities.

International audience; Background: In hepatitis C virus (HCV) infection, treatment failure is generally associated with the selection of resistance-associated substitutions (RAS) conferring reduced susceptibility to direct-acting antiviral (DAA) drugs. Resistant variants continue to replicate after the end of treatment with potential for transmission. This may result from the selection of "fitness-associated substitutions".Aim: To characterise potential "fitness-associated substitutions" in patients infected with genotype 3a failing DAA drugs METHODS: By means of shotgun metagenomics, we sequenced full-length HCV genomes at treatment initiation and at virological relapse in eight patients infected with genotype 3a with cirrhosis failing sofosbuvir and an NS5A inhibitor. The impact of amino acid changes occurring outside of DAA target regions selected in at least two patients were assessed on the in vitro susceptibility to an NS5A inhibitor and replication capacity.Results: At treatment failure, besides selection of known NS5A RASs, especially Y93H, a large number of amino acid changes was observed outside of DAA target regions. We identified four amino acid positions at which observed changes substantially improved in vitro replication capacity without affecting NS5A inhibitor susceptibility.Conclusions: This is the first in vivo observation combined with in vitro confirmation of selection of phenotypically characterised "fitness-associated substitutions" together with RASs at the time of sofosbuvir-NS5A inhibitor treatment failure in patients infected with genotype 3a with cirrhosis. Our findings may explain the persistence of resistant HCV variants after treatment in patients who did not achieve sustained virological remission.

UNLABELLED Failure to achieve sustained virological response (SVR) with hepatitis C virus (HCV) direct-acting antiviral-based regimens is commonly associated with emergence of resistance-associated variants (RAVs). To avoid cross-resistance, recent guidelines recommend that patients who have failed on nonstructural protein 5A (NS5A) inhibitors should be retreated with sofosbuvir (SOF; NS5B inhibitor) combined with simeprevir (SIM; protease inhibitor [PI]); however, supporting evidence is lacking. This "real-world" study comprised patients who had failed to achieve SVR on previous NS5A-based therapy with daclatasvir (DCV) plus pegylated interferon (Peg-IFN) and ribavirin (RBV), with (n = 3) or without (n = 13) asunaprevir (ASV; PI). All 16 patients were retreated for 12 weeks with SOF plus SIM, without RBV. Antiviral efficacy was evaluated using the primary endpoint of SVR12 (SVR 12 weeks post-treatment); on-treatment response was also assessed. Patients (N = 16; 13 male; mean age: 54 years [range, 43-73]) were chronically infected with HCV genotype (GT) 1 (1a, n = 11; 1b, n = 3) or 4 (n = 2); they had advanced fibrosis or compensated cirrhosis (FibroScan, 9.6-70 kPa; cirrhosis, n = 9); median baseline HCV-RNA level was 1.38 × 10(6) IU/mL. No patient discontinued treatment because of adverse events or virological failure. All patients achieved HCV RNA below lower limit of quantification (

Background: Sensitive and accurate hepatitis C virus (HCV) RNA detection and quantification are essential to diagnose and monitor the virological response to antiviral treatment and the emergence of resistance. Objective and study design: The aim of this study was to assess the ability of the new Xpert HCV Viral Load assay to accurately detect and quantify HCV RNA in serum and in whole blood collected on dried blood spot (DBS). Serum and whole blood from a large series of patients chronically infected with different HCV genotypes were tested in parallel for HCV RNA detection and quantification. Results: A significant relationship between HCV RNA levels measured with the Xpert HCV Viral Load assay and the two commercial real-time PCR comparators (Abbott RealTime HCV test and Cobas AmpliPrep/Cobas Taqman HCV 2.0 test) was found in serum as well as in whole blood specimens. Conclusions: The Xpert HCV Viral Load assay accurately quantifies HCV RNA regardless of the HCV genotype and can thus confidently be used to detect active HCV infection in serum and in whole blood specimens.

Rapid diagnostic tests (RDTs) represent an attractive alternative to conventional diagnostic methods for hepatitis C virus (HCV) infection. The aim of the present study was to assess the clinical performance of the new CE-marked Advanced Quality™ Rapid Anti-HCV Test for the detection of HCV antibodies in various patient populations. A total of 396 individuals, including 178 patients with chronic HCV infection, 26 patients with resolved HCV infection, and 192 subjects not infected with HCV, were studied. The clinical sensitivity and specificity in serum samples of the Advanced Quality™ Rapid Anti-HCV Test were both 99%. The new CE-marked RDT Advanced Quality™ Rapid Anti-HCV Test fulfills the World Health Organization recommendations acceptance criteria for serological assays in terms of sensitivity and specificity and can thus be confidently used for the screening of HCV antibodies.

Background With the advent of highly efficient antiviral therapies for hepatitis C virus (HCV) infection, providing broad access to diagnosis and care is needed. The dried blood spot (DBS) technique can be used to collect, store, and ship whole-blood specimens. Our goal was to assess the performance of standardized HCV diagnostic and monitoring tools in the analysis of DBS. Methods Serum specimens and whole-blood specimens collected using the DBS technique from >500 patients were tested for virological markers used to diagnose and monitor HCV infection. Results Enzyme immunoassay detection of anti-HCV antibodies in specimens from DBS was reliable after establishment of a new signal-to-cutoff ratio. HCV RNA was detected DBS from the vast majority of patients with active replication, but HCV RNA levels were substantially lower than in serum specimens, implying that only the presence or absence of HCV RNA or changes in the HCV RNA level should be taken into consideration for therapy. Detection of HCV core antigen in specimens from DBS was not a sensitive marker of chronic HCV infection. HCV genotype determination was possible in the vast majority of DBS. Conclusions This study shows that whole-blood specimens collected using the DBS technique can be confidently used to diagnose and monitor HCV infection. DBS could help improve access to care for HCV infection because they are suitable for use in large-scale screening programs, diagnosis, and therapeutic monitoring.

BACKGROUND The combination of sofosbuvir (SOF) plus an NS5A inhibitor for 12 weeks is highly efficacious in patients with chronic hepatitis C. As the costs of generic production of sofosbuvir and NS5A inhibitor are rapidly decreasing, the combination of these DAAs will be the standard treatment in most low- to middle-income countries in the future. AIM To identify key predictors of response that can be used to tailor treatment decisions. METHODS A cohort of 216 consecutive patients infected with HCV genotype 1 (1a: n = 57; 1b: n = 77), 2 (n = 4), 3 (n = 33) or 4 (n = 44) were treated with sofosbuvir (SOF) + daclatasvir (n = 176) or SOF + ledipasvir (n = 40) for 12 weeks. The viral kinetics was analysed using the biphasic model and the cure boundary was used to predict time to clear HCV. RESULTS The overall SVR rate was high (94.4%; n = 204), regardless of the time to viral suppression or low-level viraemia at the end of treatment. The model-based predicted HCV RNA levels at the end of treatment could not differentiate patients who did from those who did not achieve SVR. The presence of NS5A resistance-associated substitutions [position 28 (OR = 70.3, P

International audience; Introduction: The diagnostic procedure for chronic hepatitis C infection (CHC) usually combines anti-HCV antibody (HCV-Ab) and HCV-RNA measurement. Quantifying HCV core antigen (cAg) as a one-step procedure could shorten the diagnostic process. We aimed to assess the performance of cAg quantification in diagnosing CHC and how it is influenced by concomitant HIV or HBV infections. Methods: The cAg was quantified by an automated assay (Abbott Diagnostics) in 465 HCV-Ab negative serum samples and 544 HCV-RNA positive serum samples (n = 1009) collected in patients from the Pasteur Center in Cameroon, some of whom were infected by HBV or HIV. Its performance was evaluated in comparison to the gold standard (ELISA or PCR) by estimating its sensitivity (Se) and specificity (Sp), and by comparing the area under ROC (AUROC) curves in each patient population: HCV mono-infected, HCV-HBV and HIV-HCV co-infected. Results: Among the 465 HCV-Ab negative patients, 51 and 79 were HIV-and HBV-infected, respectively, whereas among the 544 patients with CHC, 27 and 28 were HIV-and HBV-infected, respectively. The Spearman ρ correlation coefficient between cAg and HCV-RNA was 0.75 (p < 0.00001). The assay had a sensitivity of 95.7% (95% CI: 93.2–97.5) and a specificity of 99.7% (95% CI: 98.1–10) in diagnosing CHC, corresponding to an AUROC of 0.99 (95% CI: 0.98–1.0). Being HIV-or HBV-infected did not impact the performance of cAg (Se = 96.4%, Sp = 96.2% and AUROC = 0.98 (95% CI: 0.95–1.0) in the HBV group, Se = 100%, Sp = 88.2% and AUROC = 0.99 (95% CI: 0.97–1.0) in the HIV group, p between AUROC = 0.69). Conclusions: The cAg quantification displayed a high specificity and sensitivity for the diagnosis of CHC in Cameroon, and its performance was not significantly modified by a concomitant HIV or HBV infection. In the context of CHC elimination on a global scale, using cAg quantification as a screening tool to directly identify CHC could be a reliable tool in a " test and treat " strategy.

Large-scale hepatitis C screening is required to prevent further spread of the infection, improve access to care in the context of new hepatitis C virus (HCV) drug regimens without interferon-alpha and subsequently reduce the risk of long-term complications of chronic liver disease. Rapid diagnostic tests (RDTs) represent an attractive alternative to enzyme immunoassay using blood from venepuncture. The aim of the present study was to prospectively assess the clinical performance of CE-marked RDTs detecting anti-HCV antibodies in fingerstick capillary whole blood and/or oral fluid. A total of 513 individuals, including 318 patients with chronic HCV infection, 25 patients with resolved HCV infection and 170 HCV-seronegative individuals, were prospectively enrolled. The specificity of RDTs with fingerstick whole blood varied from 98.8% to 100%. The clinical sensitivity was high for the OraQuick(®) and Toyo(®) tests (99.4% and 95.8%, respectively), but low for the Labmen(®) test (63.1%). The specificity and clinical sensitivity in crevicular fluid were both satisfactory for the OraQuick(®) test (100% and 97.6%, respectively). HCV antibody RDTs were easy and rapid to perform in the context of patient care. They were highly specific. Both the OraQuick(®) and Toyo(®) tests reached the expected level of performance for wide-scale use, with a performance advantage for the OraQuick(®) HCV test. RDTs appear to be a promising new tool for wide-scale screening of HCV infection in high-risk to medium-risk populations. Hence, careful assessment of the performance of HCV RDTs must be recommended before they can be implemented in clinical practice.

Rapid diagnostic tests (RDTs) represent an attractive alternative to enzyme immunoassays. A total of 207 individuals, including 68 HCV-seronegative subjects, 10 patients with resolved infection and 129 patients with chronic HCV infection, were studied. The specificity of RDT detection of anti-HCV antibodies in whole blood was 100% with the four RDTs tested: OraQuick(®) HCV Rapid Antibody Test, First Response HCV Card Test, ASSURE HCV Rapid Test and MultiSure HCV Antibody Assay. Their diagnostic sensitivity varied between 98.6% and 100%. RDT detection of anti-HCV antibody in whole blood collected on dried blood spots appears to be a promising new tool for broadscale screening of HCV infection in high- to medium-risk populations.

Lamivudine was the first approved inhibitor of hepatitis B virus (HBV) reverse transcriptase (RT). Lamivudine resistance develops in 53% to 76% of patients after 3 years of treatment. We extensively characterized the dynamics of HBV quasispecies variant populations in four HBV-infected patients who developed lamivudine resistance. Virological breakthrough was preceded by 2 to 4 months by the emergence of quasispecies variants bearing amino acid substitutions at RT position 204, i.e., within the YMDD catalytic motif (rtM204V/I). Three patients had a gradual switch from a YMDD variant population at baseline to a 100% lamivudine-resistant variant population, whereas the remaining patient had a fluctuating pattern of resistance variant dynamics. Careful analysis of amino acid substitutions located outside domain C of HBV RT, including those known to partially restore replication capacities in vitro, showed that the in vivo replication of HBV variants is driven by multiple forces, including intrinsic replicative advantages conferred by mutations accumulating outside domain C and the changing environment in which these variants replicate. Our findings also suggest that individual treatment optimization will require sensitive methods capable of detecting the emergence of viral resistance before the relevant variants acquire optimal replicative capacities.

International audience; BACKGROUND & AIMS:HCV requires host lipid metabolism for replication, and apolipoproteins have been implicated in the response to treatment.METHODS:We examined plasma apolipoprotein concentrations in three cohorts of patients: mono-infected patients with symptomatic acute hepatitis C (aHCV); those undergoing treatment for chronic hepatitis C (cHCV); and HIV/HCV co-infected patients being treated for their chronic hepatitis C. We also evaluated associations between apolipoproteins and IL28B polymorphisms, a defined genetic determinant of viral clearance.RESULTS:Plasma apolipoprotein H (ApoH) levels were significantly higher in patients who achieved spontaneous clearance or responded to pegylated-interferon/ribavirin therapy. Strikingly, patients carrying the IL28B rs12979860 CC SNP correlated with the plasma concentration of ApoH in all three cohorts. Both ApoH and IL28B CC SNP were associated with HCV clearance in univariate analysis. Additional multivariate analysis revealed that the association between IL28B and HCV clearance was closely linked to that of Apo H and HCV clearance, suggesting that both belong to the same biological pathway to clearance. The association between IL28B CC SNP and ApoH was not observed in healthy individuals, suggesting that early post-infection events trigger differential ApoH expression in an IL28B allele dependent manner.CONCLUSIONS:This relationship identifies ApoH as the first induced protein quantitative trait associated with IL28B, and characterises a novel host factor implicated in HCV clearance

Background Hepatitis C virus (HCV) core antigen has been proposed as a surrogate marker of HCV replication. HCV core antigen detection and quantification can thus theoretically be used instead of nucleic acid testing (NAT) to diagnose infection and manage antiviral therapy, with several advantages compared to HCV RNA assays. HCV core antigen can now be easily detected and quantified by means of a chemiluminescent microparticle immunoassay on the Abbott Architect device. Objective The aim of the present study was to evaluate the clinical performance of the Architect HCV Ag assay for the detection and quantification of HCV core antigen in patients with chronic HCV genotype 1–6 infections. Results The Architect HCV Ag assay had a specificity of 100% (95%CI: 97.8–100%). HCV core antigen levels were not influenced by the HCV genotype. The lower limit of detection of 3 fmol/L corresponded to approximately 1000 IU/mL of HCV RNA, regardless of the real-time PCR assay used. HCV core antigen and HCV RNA levels correlated for HCV genotype 1–4 ( r = 0.89 and r = 0.88 for the m 2000 and the CAP/CTM v2.0 assay, respectively). Conclusions The Architect HCV Ag assay is highly specific and easy to perform. It represents a valuable screening, diagnostic and monitoring tool, especially in the era of new all-oral, interferon-free antiviral strategies that do not require high analytical sensitivity.

We characterized a novel substitution conferring moderate resistance to telaprevir, a peptidomimetic inhibitor of hepatitis C virus protease. V36C conferred a 4.0-fold increase in the telaprevir 50% inhibitory concentration in an enzyme assay and a 9.5-fold increase in the replicon model. The replication capacity of a replicon harboring V36C was close to that of the wild-type protease. This case emphasizes the complexity of hepatitis C virus resistance to protease inhibitors.

Sustained hepatitis C virus (HCV) RNA clearance is achieved in 8 to 12% of patients with chronic HCV infection treated with alpha interferon (IFN-α) at the approved dose of 3 MU three times a week for 6 months and in about 25% of those receiving this treatment for 12 months. We used single-strand conformation polymorphism analysis combined with cloning and sequencing strategies to characterize the genetic evolution of HCV second envelope gene hypervariable region 1 (HVR1) quasispecies during and after IFN therapy in patients who failed to clear HCV RNA. Sustained HCV RNA clearance was achieved in 6% of patients. Profound changes in HVR1 quasispecies major variants were estimated to occur in 70% of the patients during and after therapy. These changes were evolutionary and were characterized by shifts in the virus population, related to selection and subsequent diversification of minor pretreatment variants. The quasispecies changes appeared to be induced by changes in the host environment likely resulting from the IFN-induced enhancement and post-IFN attenuation of neutralizing and possibly cytotoxic responses against HVR1. The remaining patients had no apparent changes in HVR1 quasispecies major variants, suggesting selection of major pretreatment variants, but some changes were observed in other genomic regions. We conclude that IFN-α administration and withdrawal profoundly alters the nature of circulating HCV quasispecies, owing to profound changes in virus-host interactions, in patients in whom sustained HCV RNA clearance fails to occur. These changes are associated with profound alterations of the natural outcome of HCV-related liver disease, raising the hypothesis of a causal relationship.

Accurate hepatitis C virus (HCV) RNA quantification is mandatory for the management of chronic hepatitis C therapy. The first-generation Cobas AmpliPrep/Cobas TaqMan HCV test (CAP/CTM HCV) underestimated HCV RNA levels by >1-log 10 international units/ml in a number of patients infected with HCV genotype 4 and occasionally failed to detect it. The aim of this study was to evaluate the ability of the Cobas AmpliPrep/Cobas TaqMan HCV test, version 2.0 (CAP/CTM HCV v2.0), to accurately quantify HCV RNA in a large series of patients infected with different subtypes of HCV genotype 4. Group A comprised 122 patients with chronic HCV genotype 4 infection, and group B comprised 4 patients with HCV genotype 4 in whom HCV RNA was undetectable using the CAP/CTM HCV. Each specimen was tested with the third-generation branched DNA (bDNA) assay, CAP/CTM HCV, and CAP/CTM HCV v2.0. The HCV RNA level was lower in CAP/CTM HCV than in bDNA in 76.2% of cases, regardless of the HCV genotype 4 subtype. In contrast, the correlation between bDNA and CAP/CTM HCV v2.0 values was excellent. CAP/CTM HCV v2.0 accurately quantified HCV RNA levels in the presence of an A-to-T substitution at position 165 alone or combined with a G-to-A substitution at position 145 of the 5′ untranslated region of HCV genome. In conclusion, CAP/CTM HCV v2.0 accurately quantifies HCV RNA in genotype 4 clinical specimens, regardless of the subtype, and can be confidently used in clinical trials and clinical practice with this genotype.

International audience; BACKGROUND & AIMS: In patients with chronic hepatitis C who failed to respond to standard therapy, high-dose pegylated interferon (IFN)-α and/or ribavirin could induce a stronger antiviral response and prevent treatment failure and HCV resistance when combined with direct-acting antivirals. The influence of genetic determinants in this context remains unknown. METHODS: Eighty-three patients infected with HCV genotype 1 who were nonresponsive to standard therapy received pegylated IFN-α2a (360 μg once per week or 180 μg twice per week) with ribavirin (1.0-1.2 or 1.2-1.6 g/d) for up to 72 weeks. Virological responses were assessed at different time points, and the influence of the IL-28B genotype was studied. RESULTS: At weeks 12 and 24, respectively, 47 (56.6%) and 50 (60.2%) patients achieved a ≥2-Log(10) decrease of HCV RNA levels; 8 (9.6%) and 21 (25.3%) patients had undetectable HCV RNA after 12 and 24 weeks of treatment, respectively. Patients with a CT IL-28B genotype responded significantly better and earlier than those with a TT genotype. In multivariate analysis, the IL-28B genotype was an independent predictor of the virological responses at weeks 4, 12, and 24. CONCLUSIONS: High-dose pegylated IFN-α with standard or high doses of ribavirin induces a potent antiviral response in a substantial number of patients who did not respond to standard therapy. The IL-28B genotype is an independent predictor of the antiviral response. High-dose pegylated IFN-α in combination with ribavirin and protease inhibitors appears as an attractive option for future study in this population.

Background & Aims: Single nucleotide polymorphisms (SNPs) associated with IL28B influence the outcome of peginterferon-alpha/ribavirin therapy of chronic hepatitis C virus (HCV) infection. We analyzed the kinetics of HCV RNA during therapy as a function of IL28B SNPs. Methods: IL28B SNPs rs8099917, rs12979860, and rs12980275 were genotyped in 242 HCV treatment-naive Caucasian patients (67% genotype 1, 28% genotype 2 or 3) receiving peginterferon-alpha 2a (180 mu g weekly) and ribavirin (1000-1200 mg daily) with serial HCV-RNA quantifications. Associations between IL28B polymorphisms and early viral kinetics were assessed, accounting for relevant covariates. Results: In the multivariate analyses for genotype 1 patients, the T allele of rs12979860 (T(rs12979860)) was an independent risk factor for a less pronounced first phase HCV RNA decline (log(10) 0.89 IU/ml among T carriers vs. 2.06 among others, adjusted p

The factors leading to spontaneous clearance of hepatitis C virus (HCV) or to viral persistence are elusive. Understanding virus-host interactions that enable acute HCV clearance is key to the development of more effective therapeutic and prophylactic strategies. Here, using a sensitive neutralization assay based on infectious HCV pseudoparticles (HCVpp), we have studied the kinetics of humoral responses in a cohort of acute-phase patients infected during a single nosocomial outbreak in a hemodialysis center. The 17 patients were monitored for the spontaneous outcome of HCV infection for 6 months before a treatment decision was made. Blood samples were taken frequently (15 ± 4 per patient). Phylogenetic analysis of the predominant virus(es) revealed infection by only one of two genotype 1b strains. While all patients seroconverted, their sera induced two opposing effects in HCVpp infection assays: inhibition and facilitation. Furthermore, the ability of sera to facilitate or inhibit infection correlated with the presence of either infecting HCV strain and divided the patients into two groups. In group 1, the progressive emergence of a relatively strong neutralizing response correlated with a fluctuating decrease in high initial viremia, leading to control of viral replication. Patients in group 2 failed to reduce viremia within the acute phase, and no neutralizing responses were detected despite seroconversion. Strikingly, sera of group 2, as well as naïve sera, facilitated infection by HCVpp displaying HCV glycoproteins from different genotypes and strains, including those retrieved from patients. These results provide new insights into the mechanisms of viral persistence and immune control of viremia.

Accurate quantification of hepatitis C virus (HCV) RNA is needed in clinical practice to decide whether to continue or stop pegylated interferon-α-ribavirin combination therapy at week 12 of treatment for patients with chronic hepatitis C. Currently the HCV RNA quantification assay most widely used worldwide is the Amplicor HCV Monitor v2.0 assay (Roche Molecular Systems, Pleasanton, Calif.). The HCV RNA extraction step can be automated in the Cobas Ampliprep device. In this work, we show that the dynamic range of HCV RNA quantification of the Cobas Ampliprep/Cobas Amplicor HCV Monitor v2.0 procedure is 600 to 200,000 HCV RNA IU/ml (2.8 to 5.3 log IU/ml), which does not cover the full range of HCV RNA levels in infected patients. Any sample containing more than 200,000 IU/ml (5.3 log IU/ml) must thus be retested after dilution for accurate quantification. These results emphasize the need for commercial HCV RNA quantification assays with a broader range of linear quantification, such as real-time PCR-based assays.

Background/Aims The aim of this study was to increase virologic response rates by individualized treatment according to the early virologic response. Methods Serum HCV-RNA was frequently quantified in patients with chronic hepatitis C ( n =270) treated with peginterferon alfa-2a (180μg/week) and ribavirin (1000–1200mg/day). After 6 weeks patients were classified as rapid (RVR), slow (SPR), flat (FPR), or null responders (NUR) and randomized within each viral kinetic class to continue therapy either with an individualized or standard regimen. Individualized therapy comprised peginterferon monotherapy (48 weeks) or shorter combination therapy (24 weeks) for RVR, triple therapy with histamine (1mg/day) (48 weeks) or prolonged combination therapy (72 weeks) for SPR, triple therapy for FPR, and high-dose peginterferon (360μg/week) plus ribavirin for NUR patients. Results Patients were categorized as RVR ( n =171), SPR ( n =65), FPR ( n =10), or NUR ( n =22). Overall end-of-treatment and sustained virologic response rates were 77 and 60% in the individualized and 77 and 66% in the standard treatment arm, respectively. Histamine in addition to peginterferon and ribavirin and high-dose peginterferon plus ribavirin did not improve virologic response rates in patients with FPR and NUR, respectively. Conclusions An improvement in virologic efficacy was not achieved with the available individualized treatment options.

Chronic hepatitis C is a common cause of liver disease, the complications of which include cirrhosis and hepatocellular carcinoma. Treatment of chronic hepatitis C is based on the use of alpha interferon (IFN-α). Recently, indirect evidence based on mathematical modeling of hepatitis C virus (HCV) dynamics during human IFN-α therapy suggested that the major initial effect of IFN-α is to block HCV virion production or release. Here, we used primary cultures of healthy, uninfected human hepatocytes to show that: (i) healthy human hepatocytes can be infected in vitro and support HCV genome replication, (ii) hepatocyte treatment with IFN-α results in expression of IFN-α-induced genes, and (iii) IFN-α inhibits HCV replication in infected human hepatocytes. These results show that IFN-α acts primarily through its nonspecific antiviral effects and suggest that primary cultures of human hepatocytes may provide a good model to study intrinsic HCV resistance to IFN-α.