Syria Laperche

Institut National de la Transfusion Sanguine, Paris, Lutetia Parisorum, Île-de-France, France

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Publications (142)426.95 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Droplet digital PCR (ddPCR), which has been recently developed to provide an absolute quantitation of target molecules without relying on the use of standard curves (1), might be an interesting alternative to conventional real-time PCR assays used for viral load (VL) determination (2, 3).…
    Journal of clinical microbiology. 07/2014;
  • Transfusion 03/2014; 54(3):744-5. · 3.53 Impact Factor
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    ABSTRACT: A French national quality control for serological and molecular diagnosis of hepatitis Delta virus (HDV) was organized. All participants detected total HDV antibodies; 8/14 failed to detect low titers of IgM; 6/11 laboratories failed to quantify and/or underestimated RNA viral load in several samples. These discrepancies are likely related to HDV molecular diversity.
    Journal of clinical microbiology 02/2014; · 4.16 Impact Factor
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    ABSTRACT: 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.
    Journal of virological methods 01/2014; · 2.13 Impact Factor
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    ABSTRACT: In France, there are no consistent data estimating hepatitis delta virus (HDV) prevalence in the general population. To better characterize HDV/HBV infection and its trends over a 15-years period from 1997 to 2011, we used data retrieved from the National Epidemiological Donors database including viral and demographic characteristics of all French HBV infected blood donors. Of the 39,911,011 donations collected over the 15 year-study-period, 6214 (1.56 in 10(4) donations) were confirmed positive for HBV from which 72.3% were tested for HDV antibodies (Ab). HDV viral load was performed using a real-time PCR assay on positive HDV Ab samples and HDV genotype determined for each positive viremic sample. Among the 4492 HBV donations, 89 (1.98%) were HDV Ab positive. After being stable around 1.1% from 1997 to 2005, this rate has continuously increased to reach 6.5% in 2010, before declining to 0.85% in 2011. Of the 61 investigated HDV Ab positive individuals, 22.9% were viremic with a viral load ranging from 10(4) to 9.8×10(7)copiesmL(-1). Genotyping revealed 12 HDV-1, 1 HDV-6 and 1 HDV-7 in accordance with the geographical origin of individuals. Such a study gives unexpected features of HBV-HDV infection in the population of blood donors which is a priori, a healthy population. The increase of HDV prevalence mainly linked to migration of population from endemic countries, demonstrates that there is still no complete control of HBV infection and must encourage HBV vaccination campaigns and systematic screening for HDV in HBV-infected.
    Journal of clinical virology: the official publication of the Pan American Society for Clinical Virology 12/2013; · 3.12 Impact Factor
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    ABSTRACT: Rapid diagnostic tests (RDT) have been developed for the detection of hepatitis B surface antigen (HBsAg). They represent a promising alternative to enzyme immunoassays and a powerful tool for large-scale screening and diagnosis of HBV infection, especially in regions without easy access to serological and molecular testing. The aims of the present study were to evaluate the characteristics and clinical performance of a new CE-marked HBsAg RDT, DRW-HBsAg v2.0 assay (Diagnostics for the Real World™, Ltd., USA), in various patient populations, including those chronically infected with HBV, patients with severe acute hepatitis of unknown origin and pregnant women with unknown HBV serological status at delivery. The lower limit of detection of the assay, evaluated in 21 clinical samples, ranged from 0.30±0.07 to 0.97±0.26 international units/mL (using Abbott Architect as a reference), depending on the HBV genotype. The assay tested positive in 100% of patients with chronic hepatitis B, 96.3% of HBsAg-positive acute hepatitis patients, and 95.2% of HBsAg-positive pregnant women. Its specificity was 98.8% in HBsAg-negative patients, 98.7% in HBsAg-negative patients with acute hepatitis of unknown origin and 97.8% in HBsAg-negative pregnant women. Amino acid substitutions in the HBsAg major hydrophilic region did not affect HBsAg detection by DRW-HBsAg v2.0. The new DRW-HBsAg v2.0 assay is a simple, rapid, easy-to-run and highly sensitive assay that can be used in both high- and low-risk populations for the diagnosis of HBsAg carriage. It appears to be a promising new tool for large-scale screening and diagnosis of HBV infection.
    Journal of clinical virology: the official publication of the Pan American Society for Clinical Virology 12/2013; · 3.12 Impact Factor
  • S. Laperche
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    ABSTRACT: Enzyme Immunoassays (EIAs) detecting antibodies (Ab) or antigen (Ag) used to avoid viral transmissions by transfusion, are the most suitable methods for blood screening because they are economical and adaptable to high-throughput testing. The continuing need to improve screening for HIV and HCV, led to develop Ag/Ab combination assays. The benefit of such assays has been widely demonstrated, since they are able to detect infected individuals in viremic pre-seroconversion phase, making them particularly attractive for ensuring blood safety when nucleic acid testing (NAT) cannot be implemented. In resource-limited countries, especially in remote-areas, blood safety is often based upon rapid tests (RT) which are easy to handle and can be used with whole blood. Nevertheless, the poor sensitivity of RT compared to EIAs could significantly impair blood safety. Because NAT could efficiently detect serologically negative donors, many developed countries have implemented this method in blood screening. NAT yields vary depending on epidemiological situations. NAT is subjected to false-negative results due to viral diversity or to extremely low viral loads, but also to false-positive due to sample cross-contamination. A repeatedly NAT reactive sample with multiplexed NAT is submitted to a virus-specific amplification testing to discriminate between the viruses, creating some problematic situations consisting of samples reactive with the screening assay but non-reactive with the discriminatory assay. Although the primary purpose of viral screening testing is to prevent pathogen transmission to recipients, confirmatory testing intends to manage donors with adverse test results and to guarantee an optimal blood supply. As EIAs show a low positive predictive value in low-prevalence countries due to frequent non-specific reactions, the use of confirmatory assays is justified. Nevertheless confirmatory tests are known to be less sensitive than EIAs in the early phase of infection and show also nonspecific reactivity leading to indeterminate results which create difficulties in managing donors. As in limited-resource countries, specific confirmatory assay cannot be used, alternate strategies for confirmatory testing have been proposed, as to simultaneously test blood with two assays and to exclude donors reactive with both, or to use screening test signal values to support confirmation. Although the direct detection of the virus through its genome might be considered as the best solution to ensure blood safety, the choice of blood screening strategy should be adapted to local epidemiology and organization constraints.
    ISBT Science Series 06/2013; 8(1).
  • Transfusion Clinique et Biologique 06/2013; 20(3):262–263. · 0.64 Impact Factor
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    ABSTRACT: The preparation of a VHH (nanobody(TM)) named IH4 that recognizes human glycophorin A (GPA) is described. IH4 was isolated by screening a library prepared from the lymphocytes of a dromedary immunized by human blood transfusion. Phage display and panning against GPA as the immobilized antigen, allowed isolating this VHH. IH4, representing 67% of the retrieved VHH sequences, was expressed as a soluble correctly folded protein in SHuffle(TM)E. coli cells routinely yielding ca. 100 mg/L of fermentation medium. Because IH4 recognizes GPA independently of the blood-group antigens, it recognizes red cells of all humans with the possible exception of those with some extremely rare genetic background. The targeted linear epitope comprises the GPA Y52PPE55 sequence. Based on surface plasmon resonance results the dissociation constant of the IH4-GPA equilibrium is 33 nM. IH4 is a stable protein with a transition melting temperature of 75.8°C (measured by differential scanning calorimetry). As proof of concept, we fused HIV p24 to IH4 and used the purified construct expressed in E. coli to show that IH4 was amenable to the preparation of autologous erythrocyte agglutination reagents: reconstituted blood prepared with serum from an HIV positive patient was readily agglutinated by addition of the bifunctional reagent.
    Analytical Biochemistry 03/2013; · 2.58 Impact Factor
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    ABSTRACT: Hepatitis C virus (HCV) protease inhibitor resistance-associated substitutions are selected during triple therapy breakthrough. This multicenter quality control study evaluated the expertise in HCV protease inhibitor resistance genotyping of 23 French laboratories. A panel of 12 well-defined blinded samples comprising two wild-type HCV strains, nine transcripts from synthetic NS3 mutant samples or from clinical strains, and one HCV RNA-negative sample was provided to the participating laboratories. The results showed that any laboratory with expertise in sequencing techniques should be able to provide reliable HCV protease inhibitor resistance genotyping. Only 0.7% erroneous results were reported over the amino acid sites studied. The accuracy of substitution identification ranged from 75% to 100%, depending on the laboratory. Incorrect results were mainly related to the methodology used. The results could be improved by changing the primers and modifying the process in order to avoid cross-contaminations. This study underlines the value of quality control programs for viral resistance genotyping, required prior to launching observational collaborative multicenter studies on HCV resistance to direct-acting antiviral agents.
    Journal of clinical microbiology 02/2013; · 4.16 Impact Factor
  • Transfusion Clinique et Biologique 01/2013; 20(3):208-209. · 0.64 Impact Factor
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    [Show abstract] [Hide abstract]
    ABSTRACT: The preparation of a VHH (nanobodyTM) named IH4 that recognizes human glycophorin A (GPA) is described. IH4 was isolated by screening a library prepared from the lymphocytes of a dromedary immunized by human blood transfusion. Phage display and panning against GPA as the immobilized antigen, allowed isolating this VHH. IH4, representing 67% of the retrieved VHH sequences, was expressed as a soluble correctly folded protein in SHuffleTME. coli cells routinely yielding ca. 100 mg/L of fermentation medium. Because IH4 recognizes GPA independently of the blood-group antigens, it recognizes red cells of all humans with the possible exception of those with some extremely rare genetic background. The targeted linear epitope comprises the GPA Y52PPE55 sequence. Based on surface plasmon resonance results the dissociation constant of the IH4-GPA equilibrium is 33 nM. IH4 is a stable protein with a transition melting temperature of 75.8 degrees C (measured by differential scanning calorimetry). As proof of concept, we fused HIV p24 to IH4 and used the purified construct expressed in E. coli to show that IH4 was amenable to the preparation of autologous erythrocyte agglutination reagents: reconstituted blood prepared with serum from an HIV positive patient was readily agglutinated by addition of the bifunctional reagent.
    Analytical Biochemistry 01/2013; · 2.58 Impact Factor
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    ABSTRACT: Strains responsible for acute hepatitis B infections (AHB) in France have not been characterized. This study was first designed to analyze the molecular epidemiology of AHB and second to describe the differences between AHB and chronic hepatitis B (CHB) exacerbations. This prospective study was based on the French mandatory notification system for AHB. 147 samples corresponding to declared cases were shipped to a central laboratory for classification as AHB or CHB according to the level of anti-HBc IgM and anti-HBc avidity. Based on biological marker values and file examination, 75 cases (59%) were classified as AHB. Independently of the acute or chronic status, genotype A (57%), D (22%) and E (14%) were the most prevalent and no phylogenetic clustering was observed among HBV sequences (n=68). Precore or basal core-promoter variants were not particularly associated with disease severity but were more prevalent in CHB. No antiviral resistant strains or immune-escape HBsAg was observed. HBV viral loads in AHB or CHB were comparable but with opposite distributions. ALT levels reached 10 times the upper normal value in 94% of AHB but only in 24% of CHB. After rigorous classification, no major difference at the genetic level was found between HBV strains isolated from AHB and CHB. Absence of potentially deleterious variant detection is reassuring. When based upon HBsAg and anti-HBc IgM determination, AHB notification may falsely include more than 40% CHB, leading to an important risk of bias in national surveillance programs of AHB.
    PLoS ONE 01/2013; 8(9):e75267. · 3.73 Impact Factor
  • The Journal of Infectious Diseases 10/2012; · 5.85 Impact Factor
  • Syria Laperche
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    ABSTRACT: BACKGROUND: Failures of blood screening due to low test quality or poor laboratory technique increase the risk of transfusion-transmitted infections. For this reason, the World Health Organization has recommended a quality control (QC) system for African blood centers. STUDY DESIGN AND METHODS: We conducted a cross-sectional research assessment of test performance at 51 blood centers in 17 African countries. A blinded, standardized panel containing 25 samples positive for human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) and negative controls was tested by the centers using their operational infectious disease testing consisting of rapid tests, enzyme immunoassays (EIAs), or antigen-antibody EIAs. Nucleic acid testing was not performed. RESULTS: The overall performances of the 42 assays were the lowest for hepatitis B surface antigen (75.6% sensitivity, 94.5% specificity), then for HCV (80.0% sensitivity, 98.1% specificity) and for HIV (81.4% sensitivity, 99.6% specificity). Poor sensitivity was driven by the use of rapid tests, which had sensitivities of 47.4% for HBV, 63.7% for HCV, and 72.4% for HIV. From a blood screening point of view, 321 (5.6%) infected units would have been transfused due to false-negative results. Assuming that those that were missed by rapid tests (84%) would have been detected by EIAs, 270 viral contaminations (92 HIV, 65 HCV, and 113 HBV) would have been avoided. CONCLUSION: These results support the discontinuation of rapid tests and implementation of antigen-antibody EIAs whenever possible in Africa. This successful QC program highlights the need for promoting such periodic external quality assessment studies.
    Transfusion 07/2012; · 3.53 Impact Factor
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    ABSTRACT: In France, HIV infection diagnosis was modified by a decree, published in 2010, that requires the use of HIV Ag/Ab assays able to detect at least 2 IU/ml of p24Ag. This measure raises the concern of the capacity of these assays to equally detect all HIV variants. To assess the performance of HIV Ag/Ab assays for the detection of p24Ag from diverse HIV isolates. Ten HIV Ag/Ab assays were compared using two p24Ag reference standards, 297 samples from 99 HIV-1 and HIV-2 cell-culture derived isolates including various subtypes and groups, and 9 native specimens from subjects with primary HIV infection. The p24Ag limit of detection (LOD) ranged from 0.505 IU/ml to 1.90 1 IU/ml and, from 11.9 pg/ml to 33.5 pg/ml when using WHO and French national standards, respectively. The overall percentage of positive samples ranged from 26.8% to 74.5%. Five assays failed to detect all dilutions of at least one group M subtype, three missed all group O and six all the group P samples. Three assays were able to detect 2-10 of the 30 HIV-2 samples. The distribution of LODs for each group M isolate showed a wide dispersion between the assays. Percentage of isolates detected at a p24Ag level less than 2 IU/ml varied from 22% to 98.7%. This study demonstrated that, even though their analytical sensitivity fulfills the requirements, many of HIV Ag/Ab assays could fail to detect HIV primary infection due to HIV-1 non-B, non-M and HIV-2 strains.
    Journal of clinical virology: the official publication of the Pan American Society for Clinical Virology 07/2012; 55(2):121-7. · 3.12 Impact Factor
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    ABSTRACT: BACKGROUND: The risk of hepatitis B virus (HBV) transmission by transfusion is higher than that of other blood-borne viruses. In France, before the introduction of HBV nucleic acid testing (NAT) in 2010, blood donations were tested for hepatitis B surface antigen (HBsAg) and antibodies against hepatitis B core antigen, and the residual risk of HBV transfusion related to preseroconversion acute phase was estimated at 0.54 per million donations. The additional value of the implementation of a highly sensitive HBV NAT to prevent such transmissions is discussed. STUDY DESIGN AND METHODS: Two lookback investigations based on HBV seroconversion of repeat donors were performed. Donors and recipients were followed up in multiple samples that were tested for HBV serologic and molecular markers. RESULTS: The recipients have shown posttransfusion HBsAg seroconversion. The archived samples from the implicated donations were positive for HBV DNA at extremely low viral load in both cases. HBV isolates from donors and recipients of each case were organized in the same cluster with 100% identities into Genotypes A2 and B4, respectively. One recipient spontaneously recovered from infection while the second was successfully treated. CONCLUSION: The present cases highlight the importance of introducing highly sensitive HBV NAT to prevent transmission. Moreover, the lookback studies based on appropriate molecular and serologic investigations of patients transfused with previous donations from newly identified HBV-infected repeat donors offer the opportunity to treat a recently infected recipient.
    Transfusion 06/2012; · 3.53 Impact Factor
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    ABSTRACT: Natural variation and mutations in the envelope protein (S) of hepatitis B virus can translate into HBsAg variants no longer detectable by conventional HBsAg assays. The aim of the study was to assess the performance of 13 commercial assays currently used for screening and clinical analysis of HBsAg variants. The limit of detection (LOD) for each assay was established using two reference standards (WHO HBsAg 00/588 and the SFTS French reference). Sensitivity was evaluated using different panels. Panel 1 included 25 recombinant HBs variants at three concentrations, panels 2 and 4 included 8 recombinant HBsAg variants and 9 wild-type proteins (genotypes A-F), respectively, panel 3 included 16 natural HBsAg variants. LODs ranged from 0.011 to 0.095 IU/ml with the WHO standard, and from 0.021 to 0.326 ng/ml with the French reference. The overall percentage of positive signals using HBsAg variants ranged from 62.9% to 97.9%. Three substitutions: T123, D144A and G145, were negative at all concentrations with at least one assay. Our findings show that, although they fulfil CE requirements for analytical sensitivity (LODs below 0.13 IU/ml), HBsAg assays may vary in their capacity to detect HBsAg variants. This limit in diagnosis performance should encourage the health regulatory agencies to include HBsAg variant panels in the evaluation process.
    Journal of clinical virology: the official publication of the Pan American Society for Clinical Virology 01/2012; 53(4):338-45. · 3.12 Impact Factor
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    ABSTRACT: It remains unclear how the detection of hepatitis B core antibody (anti-HBc) in the absence of hepatitis B surface antigen (HBsAg) and antibody (anti-HBs) should be interpreted and whether all patients with this pattern need to be tested for hepatitis B virus (HBV)-DNA. This study aimed at reassessing the significance of 'anti-HBc alone' in unselected sera referred to the clinical laboratory and determining whether significant HBV viraemia can be found in this setting. Of the 6431 patients tested for HBsAg, total anti-HBc and anti-HBs in a Paris hospital over a 1-year period, 362 (5.6%) had 'anti-HBc alone' (24.8% of anti-HBc-positive patients). Only 11 of the 362 sera (3.0%) were found to be false positive. One patient was in the resolving phase of acute hepatitis B. HBV-DNA was detected in 10 of 362 (2.8%) patients, using a commercial standardized assay (threshold: 350 IU/mL). Viral loads exceeded 10(4) copies/mL in 6 of 10 patients. Mutations in the HBsAg immunodominant region were identified in seven of the viraemic patients. HBsAg was detected in only two cases when retested by one of the latest, multivalent assays. Neither human immunodeficiency virus nor hepatitis C virus serostatus distinguished between patients with and without HBV-DNA. In conclusion, 'anti-HBc alone' should be considered a risk marker for a so-called 'false occult' HBV infection with significant viraemia. Indeed, results in this hospital population indicate that a small proportion of patients with 'anti-HBc alone' have high viral loads, revealing the occurrence of infection with HBV mutants that escape detection even by multivalent HBsAg assays.
    Journal of Viral Hepatitis 10/2011; 18(10):721-9. · 3.08 Impact Factor
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    Journal of clinical microbiology 09/2011; 49(9):3446. · 4.16 Impact Factor

Publication Stats

1k Citations
426.95 Total Impact Points

Institutions

  • 1997–2014
    • Institut National de la Transfusion Sanguine, Paris
      Lutetia Parisorum, Île-de-France, France
  • 2011
    • Institut de France
      Lutetia Parisorum, Île-de-France, France
    • University of Yaounde I
      • Faculty of Medicine and Biomedical Sciences
      Yaoundé, Centre Province, Cameroon
  • 2010
    • University of Paris-Est
      Centre, France
  • 2008–2009
    • Université Paris-Est Créteil Val de Marne - Université Paris 12
      Créteil, Île-de-France, France
    • University of Tours
      Tours, Centre, France
  • 2002–2008
    • Institut de veille sanitaire
      • Department of Infectious Diseases
      Charenton-le-Pont, Ile-de-France, France
  • 2006
    • Centre Hospitalier Universitaire de Toulouse
      • Laboratoire de Virologie
      Tolosa de Llenguadoc, Midi-Pyrénées, France