C Negrier

University of Lyon, Lyons, Rhône-Alpes, France

Are you C Negrier?

Claim your profile

Publications (182)784 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The present study seeks to demonstrate the feasibility of avoiding the preliminary phase, which is mandatory in all conventional approaches for internal quality control (IQC) management. Apart from savings on the resources consumed by the preliminary phase, the alternative approach described here is able to detect any analytic problems during the startup and provide a foundation for subsequent conventional assessment. A new dynamically updated predictive control chart (PCC) is used. Being Bayesian in concept, it utilizes available prior information. The manufacturer's prior quality control target value, the manufacturer's maximum acceptable interassay coefficient of variation value and the interassay standard deviation value defined during method validation in each laboratory, allow online IQC management. An Excel template, downloadable from journal website, allows easy implementation of this alternative approach in any laboratory. In the practical case of prothrombin percentage measurement, PCC gave no false alarms with respect to the 1ks rule (with same 5% false-alarm probability on a single control sample) during an overlap phase between two IQC batches. Moreover, PCCs were as effective as the 1ks rule in detecting increases in both random and systematic error after the minimal preliminary phase required by medical biology guidelines. PCCs can improve efficiency in medical biology laboratories.
    Blood coagulation & fibrinolysis: an international journal in haemostasis and thrombosis 05/2015; DOI:10.1097/MBC.0000000000000314 · 1.38 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: IntroductionPost-translational modifications of the CHO-cell-derived-recombinant human factor IX (FIX) currently used for the treatment of hemophilia B (HB) are different from plasma derived FIX. Our previous studies described a rFIX (HIX) having better profile of post-translational modifications than rFIX produced by CHO cells. The aim of the study consisted to verify the improved post-translational modifications effect of HIX on in vivo recovery.Materials and methodsHIX has been produced in a bioreactor and then purified from supernatants. In vitro activation and activity were evaluated measured by thrombin generation tests (TGT) and compared to commercial molecules, Benefix®, Mononine®. The three molecules were then administrated (i.v.) to FIX-knockout mice and two minutes after injection, blood samples were collected and subjected to human FIX-specific-ELISA and TGT.ResultsThe clotting function of HIX, activation courses of HIX by FXIa and FVIIa-TF complex appear normal as did activation of Benefix®, Mononine® and TG constants of each FIX were equivalent. After injection to HB mice, circulating HIX did not present any significant difference in term of antigen value with Benefix®. Intriguingly, TGT were clearly exhibiting a better velocity for HIX than Benefix® and Mononine®. These data suggested that HIX may improve in vivo coagulant efficacy in comparison with the two commercial FIX injected at the same dose.Conclusion The study shows that HuH-7-derived-rFIX has better in vivo haemostatic activity in hemophilia B mice compared to the reference rFIX molecule despite similar in vivo recovery rates, suggesting that HuH-7 cells could represent an effective cellular system for production of rFIX.
    Haemophilia 05/2015; DOI:10.1111/hae.12688 · 2.47 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Hemophilia A and B are inherited bleeding disorders characterized by deficiencies in procoagulant factor VIII (FVIII) or factor IX (FIX), respectively. There remains a substantial unmet medical need in hemophilia, especially in patients with inhibitory antibodies against replacement factor therapy, for novel and improved therapeutic agents that can be used prophylactically to provide effective hemostasis. Guided by reports suggesting that co-inheritance of prothrombotic mutations may ameliorate the clinical phenotype in hemophilia, we developed an RNA interference (RNAi) therapeutic (ALN-AT3) targeting antithrombin (AT) as a means to promote hemostasis in hemophilia. When administered subcutaneously, ALN-AT3 showed potent, dose-dependent, and durable reduction of AT levels in wild-type mice, mice with hemophilia A, and nonhuman primates (NHPs). In NHPs, a 50% reduction in AT levels was achieved with weekly dosing at approximately 0.125 mg/kg, and a near-complete reduction in AT levels was achieved with weekly dosing at 1.5 mg/kg. Treatment with ALN-AT3 promoted hemostasis in mouse models of hemophilia and led to improved thrombin generation in an NHP model of hemophilia A with anti-factor VIII inhibitors. This investigational compound is currently in phase 1 clinical testing in subjects with hemophilia A or B.
    Nature medicine 04/2015; 21(5). DOI:10.1038/nm.3847 · 28.05 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Hemophilia B is an inherited X-linked recessive bleeding disorder, due to a defect in human factor IX (FIX). The main treatment for hemophilia B is replacement therapy using FIX concentrates. Prophylactic treatment in severe hemophilia B is very effective but is limited by cost issues. Production of a recombinant FIX (rFIX) with enhanced clotting activity, offering the possibility of fewer infusions and fewer costs with similar efficacy, is one of the current challenges for hemophilia B treatment. The present study focused on an important amino acid sequence known to be involved in the interaction of activated FIX (FIXa) with its cofactor, activated factor VIII (FVIIIa). Using site-directed mutagenesis of glutamate E410 (c240, chymotrypsin numbering), four recombinant FIX-E410 (E410H, A, L and N) mutants were developed and produced by the human hepatoma cell line Huh-7. The in-vitro clotting activity of mutant FIX molecules was 3 to 5-fold higher than wild-type recombinant FIX (FIX-WT). FIX-E410H compound showed the highest in-vitro procoagulant activity. Enhanced specific activity was confirmed using thrombin generation assay. FIX-E410H induced 5.2-fold higher thrombin generation than FIX-WT. In hemophilia B mice, we observed significantly higher in-vivo clotting activity and thrombin generating capacity with FIX-E410H compared to FIX-WT. We demonstrated that increased procoagulant activity of FIX-E410H was mainly explained by 2.5- fold enhanced affinity of the mutant for human FVIIIa. We have engineered and characterized four improved FIX proteins with enhanced in-vitro and in-vivo activity. Future studies are required to evaluate the immunogenicity of FIX-E410. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Thrombosis Research 03/2015; 135(5). DOI:10.1016/j.thromres.2015.02.034 · 2.43 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We report the largest international study on Glanzmann thrombasthenia (GT), an inherited bleeding disorder where defects of the ITGA2B and ITGB3 genes cause quantitative or qualitative defects of the αIIbβ3 integrin, a key mediator of platelet aggregation. Sequencing of the coding regions and splice sites of both genes in members of 76 affected families identified 78 genetic variants (55 novel) suspected to cause GT. Four large deletions or duplications were found by quantitative real-time PCR. Families with mutations in either gene were indistinguishable in terms of bleeding severity that varied even among siblings. Families were grouped into type I and the rarer type II or variant forms with residual αIIbβ3 expression. Variant forms helped identify genes encoding proteins mediating integrin activation. Splicing defects and stop codons were common for both ITGA2B and ITGB3 and essentially led to a reduced or absent αIIbβ3 expression; included was a heterozygous c.1440-13_c.1440-1del in intron 14 of ITGA2B causing exon skipping in 7 unrelated families. Molecular modeling revealed how many missense mutations induced subtle changes in αIIb and β3 domain structure across both subunits thereby interfering with integrin maturation and/or function. Our study extends knowledge of Glanzmann thrombasthenia and the pathophysiology of an integrin. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
    Human Mutation 02/2015; 36(5). DOI:10.1002/humu.22776 · 5.05 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This study aims to determine the way to predict the haemophilia A (HA) carrier status and the potential severity in six females with low FVIII:C levels (<0.50 IU mL(-1) ), F8 gene variations and without family history of HA. Except p.Ser577Tyr, F8 gene variations that we reported have never been described (p.Leu107His, p.Pro521Leu, p.Val682Leu, p.Leu2032Pro, p.Ala315dup). Prediction of their potential causal impact was studied by two strategies: bioinformatics approaches and site-directed mutagenesis followed by FVIII cellular expression into COS-1 cell. FVIII clotting assay (FVIII:C) and antigen (FVIII:Ag) were assayed in vitro. In silico analysis showed the probably damaging effect of all substitutions and the full conservation of the residues across mammalian species, except for p.Leu2032Pro. The in vitro variant expression model showed abnormal intra and/or extracellular FVIII:C and FVIII:Ag levels for five mutations, which suggest their causality in HA and provide informations about the involved mechanism. We suspect a defect in synthesis and secretion for p.Leu107His, p.Ala315dup and p.Pro521Leu. The mutation p.Val682Leu only affects the FVIII function while p.Ser577Tyr alters function and synthesis. The variant p.Leu2032Pro is probably a polymorphism because no alteration of the FVIII protein expression was observed in vitro. In vitro results suggest that mutations p.Ser577Tyr and p.Ala315dup could led to a severe HA in men. This study demonstrates the ability of this in vitro cellular expression model to contribute to the diagnosis strategy for female suspected of being HA carrier, without HA family history and with a novel F8 gene variation and to provide new criteria for the genetic counselling. © 2015 John Wiley & Sons Ltd.
    Haemophilia 02/2015; 21(3). DOI:10.1111/hae.12651 · 2.47 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We describe a family with an autosomal dominant disorder characterized by severe trauma- and surgery-related bleeding. The proband, who experienced life-threatening bleeding during a routine operation, had normal clotting times, but markedly reduced prothrombin consumption. Plasma levels of all coagulation factors and of the main coagulation inhibitors were normal. Thrombin generation at low triggers was severely impaired and mixing experiments suggested the presence of a coagulation inhibitor. Using whole exome sequencing, the underlying genetic defect was identified as the THBD c.1611C>A mutation (p.Cys537Stop), predicting a truncated form of thrombomodulin that is shed from the vascular endothelium. The patient had decreased expression of endothelium-bound thrombomodulin, but extremely elevated levels of soluble thrombomodulin in plasma, impairing the propagation phase of coagulation via rapid activation of protein C and consequent inactivation of FVa and FVIIIa. The same thrombomodulin mutation has been recently described in an unrelated British family with strikingly similar features. Copyright © 2015 American Society of Hematology.
    Blood 01/2015; 125(9). DOI:10.1182/blood-2014-10-604553 · 10.43 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Inhibitor development is the most serious and challenging complication in the treatment of severe haemophilia A. Up to 38% of such patients develop inhibitors with current recombinant factor VIII (rFVIII) products produced in hamster cell lines. Human-cl rhFVIII is a new generation fully sulfated B-domain-deleted FVIII coagulant glycoprotein, which is generated from a human cell line. Thus, there are no non-human epitopes which would be potentially immunogenic. This molecule has significantly higher VWF-binding affinity compared with existing full-length rFVIII produced in hamster cell lines. The development aim of Human-cl rhFVIII is to address the challenges of FVIII inhibitors and frequent infusions during prophylaxis. Human-cl rhFVIII's mean half-life is very comparable to some of the newer products which involve modification of the FVIII molecule to extend the circulating half-life. There are promising data concerning the use of a personalized prophylaxis regimen with Human-cl rhFVIII. Preliminary data indicate a median dosing interval of 3.5 days with 66.7% of the patients on a twice per week or fewer infusions schedule combined with a low bleeding rate and no increased FVIII consumption when compared to standard prophylaxis. No product-specific laboratory assay is required to monitor the coagulation activity for Human-cl rhFVIII. The results of registration clinical trials with Human-cl rhFVIII as well as the ongoing studies in previously untreated patients (NuProtect) and personalized prophylaxis study in previously treated patients (NuPreviq), will be discussed. The manufacturer has received marketing authorization for Human-cl rhFVIII in Europe and Canada under the name Nuwiq(®) and plans to launch it in the USA and globally in 2015. © 2014 John Wiley & Sons Ltd.
    Haemophilia 01/2015; 21 Suppl 1:1-12. DOI:10.1111/hae.12582 · 2.47 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This multinational, randomized, single-blind trial (NCT01333111 [www.clinicaltrials.gov]) investigated safety and efficacy of nonacog beta pegol, a recombinant glycoPEGylated factor IX (FIX) with extended half-life, in 74 previously treated hemophilia B patients (FIX activity ≤2 IU/dL). Patients received prophylaxis for 52 weeks, randomized to 10 IU/kg or 40 IU/kg once weekly, or on-demand treatment for 28 weeks. No patients developed inhibitors and no safety concerns were identified. Three-hundred and forty-five bleeding episodes were treated with an estimated success rate of 92.2%. The median annualized bleeding rates (ABRs) were 1.04 in the 40 IU/kg prophylaxis arm, 2.93 in the 10 IU/kg prophylaxis arm, and 15.58 in the on-demand treatment arm. In the 40 IU/kg arm, 10 of 15 patients (66.7%) experienced no bleeding episodes into target joints, compared with 1 of 13 patients (7.7%) in the 10 IU/kg arm. Health-related quality of life (HR-QoL) assessed with the EQ-5D VAS score improved from median 75 to 90 in the 40 IU/kg prophylaxis arm. Nonacog beta pegol was well tolerated and efficacious for treatment of bleeding episodes, and associated with low ABRs in patients on prophylaxis. Once-weekly prophylaxis with 40 IU/kg resolved target joint bleeds in 66.7% of the affected patients and improved HR-QoL.
    Blood 09/2014; 124(26). DOI:10.1182/blood-2014-05-573055 · 10.43 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In the phase 3 B-LONG [Recombinant Factor IX Fc Fusion Protein (rFIXFc) in Subjects with Haemophilia B] study, rFIXFc dosed every 1–2 weeks was safe and efficacious in previously treated subjects with haemophilia B. To date, there are no evaluations of transitioning from conventional to long-acting factor IX (FIX) prophylaxis. This post-hoc analysis of B-LONG subjects compared prophylaxis with other FIX products and rFIXFc. Pre- and on-study data were analysed to assess dosing regimen, weekly FIX consumption and annualized bleeding rates (ABRs). Population pharmacokinetics models were used to generate FIX activity profiles with rFIXFc and recombinant FIX prophylaxis. Thirty-nine subjects, previously treated prophylactically, were evaluated. Prior to study, most subjects (69·2%) received twice-weekly FIX infusions; on study, subjects infused rFIXFc once every 1–2 weeks with c. 30–50% reductions in weekly consumption. On-study estimated mean ABRs were lower than pre-study estimated mean ABRs. Models predicted that rFIXFc administered 50 iu/kg weekly and 100 iu/kg every 10 d would maintain steady-state FIX trough levels ≥1 iu/dl in 95·4% and 89·2% of subjects, respectively. These results indicate that patients receiving rFIXFc prophylaxis can markedly reduce infusion frequency and FIX consumption, have a greater likelihood of maintaining FIX activity >1 iu/dl and experience fewer bleeding episodes compared with prior FIX prophylaxis.
    British Journal of Haematology 09/2014; DOI:10.1111/bjh.13109 · 4.96 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: IntroductionRecently, rapid immunoassays have been developed to allow the detection of antibodies anti-PF4/heparin. In this prospective study, we evaluated the performances of a automatized immunoassay (HemosIL HIT-Ab) in comparison with an ELISA (Zymutest HIA IgG) used for the diagnosis of heparin-induced thrombocytopenia (HIT) in association with the 4T's score.Methods According to the 4T's score, samples with score ≤3 had no further analysis. Two immunological assays Zymutest HIA IgG and HemosIL HIT-Ab were performed in samples with score ≥4. In patients with at least one positive immunological assay or two negative immunological assays but with high-pretest probability (4T's score ≥6), HIT was screened by one functional assay using washed platelets.ResultsThe sensitivities of both assays were excellent and comparable (100%). The specificity was 92.3% for ELISA and 91.2% for HemosIL HIT-Ab. The analysis of the operating characteristics showed that both assays have almost identical ROCs (AUROC, 0.9951 and 0.9853, respectively, for ELISA and HemosIL HIT-Ab) and the calculating of the κ coefficient revealed a good agreement (0.67).Conclusion Performance characteristics of the HemosIL HIT-Ab are comparable to the Zymutest HIA IgG. The HemosIL HIT-Ab can be used in association with the 4T's score to rule out HIT.
    International journal of laboratory hematology 07/2014; 37(2). DOI:10.1111/ijlh.12275 · 1.87 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Bernard-Soulier syndrome (BSS) is a rare autosomal recessive bleeding disorder characterized by defects of the GPIb-IX-V complex, a platelet receptor for von Willebrand factor (VWF). Most of the mutations identified in the genes encoding for the GP1BA (GPIbα), GP1BB (GPIbβ), and GP9 (GPIX) subunits prevent expression of the complex at the platelet membrane or more rarely its interaction with VWF. As a consequence, platelets are unable to adhere to the vascular subendothelium and agglutinate in response to ristocetin. In order to collect information on BSS patients, we established an International Consortium for the study of BSS, allowing us to enrol and genotype 132 families (56 previously unreported). With 79 additional families for which molecular data was gleaned from the literature, the 211 families characterized so far have mutations in the GP1BA (28%), GP1BB (28%) or GP9 (44%) genes. There is a wide spectrum of mutations with 112 different variants, including 22 novel alterations. Consistent with the rarity of the disease, 85% of the probands carry homozygous mutations with evidence of founder effects in some geographical areas. This overview provides the first global picture of the molecular basis of BSS and will lead to improve patient diagnosis and management.
    Human Mutation 06/2014; DOI:10.1002/humu.22607 · 5.05 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: An ideal medical biology internal quality control (IQC) plan should both monitor the laboratory methods efficiently and implement the relevant clinical-biological specifications. However, many laboratories continue to use the 12s quality control rule without considering the high risk of false rejection and without considering the relationship of analytical performance to quality requirements. Alternatively, one can move to the Bayesian arena, enabling probabilistic quantification of the information coming in, on a daily basis from the laboratory's IQC tests, and taking into account the laboratory's medical and economic contexts. Using the example of one-stage clotting factor VIII assay, the present study compares frequentist (12s quality control rule) and Bayesian IQC management with respect to prescriber requirements, process start-up phase issues, and abnormal scenarios in IQC results. To achieve comparable confidence, the traditional 12s quality control rule requires more data than the Bayesian approach in order to detect an increase in the random or systematic error of the method. Moreover, the Bayesian IQC management approach explicitly implements respect of prescriber requirements in terms of calculating the probability that the variable in question lies in a given predefined interval: for example, the factor VIII concentration required after knee surgery in a hemophilia patient.
    Blood coagulation & fibrinolysis: an international journal in haemostasis and thrombosis 03/2014; 25(6). DOI:10.1097/MBC.0000000000000105 · 1.38 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Thirty per cent of patients with mild haemophilia A (MHA) present markedly different FVIII: C level when assayed by one-stage clotting and two-stage chromogenic assays. It is, therefore, a real clinical challenge to predict the individual bleeding risk of these patients. The aim of the present work was to study the relationship between the bleeding tendency of these patients with the results of a panel of phenotypic and genotypic tools. Thirty-six patients with MHA were included in this multicentre prospective clinical study. The severity of bleeding symptoms was evaluated using the ISTH/SSC score. FVIII:C levels were measured using an activated partial thromboplastin time-based one-stage FVIII assay (FVIII: C1) and three commercial chromogenic kits (FVIII:CR). FVIII antigen levels, thrombin generation measurement and FVIII gene mutation analysis were also performed. Our results showed that a one-stage FVIII: C assay cannot rule out the diagnosis of MHA, a combined use of FVIII:C1 with a FVIII:CR is suitable for detecting MHA. We observed that FVIII:CR results better reflected the clinical bleeding tendency of patients compared to FVIII:C1. We also observed a relationship between thrombin generation (TG) capacity and FVIII:CR of these patients. FVIII gene mutation analysis showed mutations previously reported in MHA patients with discrepant FVIII:C measurements, but with no predictive value of the individual bleeding phenotype of patients. Overall, we observed a relationship between chromogenic FVIII:C results, TG assay and bleeding tendency of patients with discrepant FVIII:C measurements, while FVIII:C1 was not well correlated with clinical bleeding phenotype in this particular population.
    Haemophilia 02/2014; DOI:10.1111/hae.12381 · 2.47 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The development of inhibitors and the need for frequent venous access for FVIII injection are major challenges in current haemophilia treatment. Presently available recombinant FVIII (rFVIII) products produced in hamster cell lines are associated with inhibitor formation in up to 32% of previously untreated patients. The new human cell line-derived recombinant human FVIII (Human-cl rhFVIII) protein is the first native, unmodified truly human rFVIII product produced in a human cell line without additive animal proteins. The aim of using a human cell line for the production of rFVIII is the avoidance of non-human epitopes on rFVIII, thereby potentially reducing the rate of inhibitor development, avoiding allergic reactions and allowing personalized prophylaxis with the chance of fewer infusions. Studies to date show that prophylaxis with Human-cl rhFVIII prevents 96% of bleeding events in adults with severe haemophilia A when compared to on-demand treatment. Available pharmacokinetic data with a mean half-life of 17.1 h allow personalized prophylaxis with the chance of fewer infusions. Studies in previously treated children and adults indicate that Human-cl rhFVIII is efficacious and safe in the prevention and treatment of bleeding episodes and that none of the treated patients developed inhibitors or allergic reactions thus far.
    Haemophilia 01/2014; 20 Suppl 1:1-9. DOI:10.1111/hae.12322 · 2.47 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Haemophilia A (HA) is an X-linked recessive bleeding disorder, caused by a wide variety of mutations in the factor VIII (F8) gene, leading to deficiency in the activity of coagulation FVIII. These mutations can affect all the F8 exons from the initiation codon to the termination codon, however, only few molecular changes in the promoter region of the F8 gene were reported so far. Here, we describe six nucleotide variations (c.-51G>A, c.-218T>C, c.-219C>T, c.-219delC, c.-221T>A and c.-664G>A) detected in the F8 promoter and their correlation with clinical phenotype of the patients. Potential role of these mutations in HA was also assessed. Causality was demonstrated with transient transfection experiments using luciferase reporter gene plasmids and computational analysis. Two molecular changes (c.-51G>A and c.-664G>A) did not seem to affect the promoter function of the F8 gene whereas c.-218T>C, c.-219C>T, c.-219delC, c.-221T>A mutations had an impact on the F8 promoter function and were responsible for HA. Furthermore, these mutations were associated with resistance to 1-deamino-8-d-argininevasopressin (desmopressin) therapy when they were causative. When molecular variation was detected in F8 promoter, we propose to use prediction software and to verify predictions by reporter gene analysis. If the mutation is causative, it will be probably associated with a lack of therapeutic response to desmopressin and this clinical implication should be considered by clinicians.
    Haemophilia 12/2013; 20(2). DOI:10.1111/hae.12346 · 2.47 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Standardization of pre-analytical conditions is the obligatory step for all potential diagnostic tests. Spatial clot growth (Thrombodynamics) is a new global hemostasis assay that considers spatial organization of coagulation. The principal parameter is rate of fibrin clot growth from the tissue-factor coated surface. In this work we studied the pre-analytical variables of Thrombodynamics assay that include conditions of blood collection, sample preparation and storage. Blood of apparently healthy volunteers was used. Eight types of citrate blood collection tubes were tested, centrifugation conditions for plasma preparation were evaluated and impact of plasma freezing/thawing was tested. Among the blood collection tubes tested, BD Vacutainer glass tubes showed a significantly higher clot growth rate compared to plastic tubes. There was no difference between 3.2% and 3.8% of sodium citrate. For plasma preparation, a single 15min centrifugation at 1 600g shows significantly increased clot growth rate compared to plasma obtained by two sequential centrifugations (15min 1 600g, 5min 10 000g). There was no significant difference between 1 600g and 2 100g if the second centrifugation was performed. For the second centrifugation there was no difference between 20min at 1 600g and 5min at 10 000g. Frozen-thawed plasma showed increased clot growth rate compared to fresh plasma. The data represent the necessary steps for the standardization of Thrombodynamics assay and for the formulation of the operating guide.
    Thrombosis Research 12/2013; 133(3). DOI:10.1016/j.thromres.2013.12.014 · 2.43 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Patients with haemophilia A and inhibitors are at high risk for severe bleeding, progression of joint disease and deterioration of health-related quality of life (HRQoL). To determine the impact of prophylaxis with an activated prothrombin complex concentrate (aPCC) on HRQoL, HRQoL was assessed using the Short-Form (SF)-36 Health Survey and the EQ-5D questionnaire in subjects ≥14 years participating in a prospective, randomized, crossover study comparing 6 months of aPCC prophylaxis with 6 months of on-demand therapy. Eighteen of 19 patients completed the survey or questionnaire before and after the on-demand therapy and prophylaxis periods. A general trend towards improved HRQoL after prophylaxis was observed for the 18 evaluable patients in all SF-36 dimensions except for vitality/energy and physical functioning. After prophylaxis, 'good responders,' defined as patients experiencing ≥50% reduction in bleeding, exhibited statistically and clinically significant differences in the physical component score (P = 0.021), role - physical (P = 0.042), bodily pain (P = 0.015), and social functioning (P = 0.036). Similarly, the EQ-5D health profile showed a trend towards improvement after prophylaxis in all evaluable patients. Among the good responders, improvements did not differ from those observed after on-demand treatment. EQ visual analogue scale values were slightly improved following prophylaxis for all evaluable patients and the EQ-5D utility index improved in the good responders only. During prophylaxis, patients missed significantly fewer days from school or work because of bleeding than during on-demand treatment (P = 0.01). In conclusion, by significantly reducing bleeding frequency in good responders, aPCC prophylaxis improved HRQoL compared with on-demand treatment.
    Haemophilia 06/2013; 19(5). DOI:10.1111/hae.12178 · 2.47 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: OBJECTIVE: Bleeding is the main complication of warfarin therapy, even patients with an INR in the target range can suffer bleeding, suggesting that INR does not perfectly reflect the therapeutic effect of warfarin. We hypothesized the INR might underestimate the level of anticoagulation in a subject with a lower factor IX (FIX) level than average. METHODS & RESULTS: We modeled warfarin anticoagulation in our in vitro thrombin generation (TG) model by adjusting the levels of vitamin K-dependent factors to those of patients with an INR of 2-3. Variation in FIX had a marked effect on TG but had no effect on the PT-INR. A prospective observational, cross-sectional clinical study including 341 consecutive patients admitted to the emergency department with an INR between 2 and 3, showed a statistically lower FIX activity in bleeders (p=0.004) compared to others. No correlation was found between TG capacity and PT-INR results (p=0.36).However, in patients, presenting with warfarin-related hemorrhage, TG was significantly lower (p<0.001) than others. And a correlation on the boundary of significance was observed between TG capacity and FIX levels (p=0.09). CONCLUSION: These data demonstrates that patients who bleed when their PT-INR is in the target range 2-3 might have defective TG related to a lower level of FIX than expected. This article is protected by copyright. All rights reserved.
    Journal of Thrombosis and Haemostasis 04/2013; 11(6). DOI:10.1111/jth.12244 · 5.55 Impact Factor
  • Source
    Expert Review of Hematology 04/2013; 6(2):111-3. DOI:10.1586/ehm.13.12 · 2.14 Impact Factor

Publication Stats

4k Citations
784.00 Total Impact Points

Institutions

  • 2004–2015
    • University of Lyon
      Lyons, Rhône-Alpes, France
  • 1998–2015
    • Hospices Civils de Lyon
      Lyons, Rhône-Alpes, France
    • Aarhus University Hospital
      • Department of Clinical Immunology
      Århus, Central Jutland, Denmark
  • 1998–2014
    • Claude Bernard University Lyon 1
      Villeurbanne, Rhône-Alpes, France
  • 1993–2014
    • CHU de Lyon - Groupement Hospitalier Edouard Herriot
      Lyons, Rhône-Alpes, France
  • 2013
    • CHU de Lyon - Hôpital de la Croix-Rousse
      Lyons, Rhône-Alpes, France
  • 2007
    • French National Centre for Scientific Research
      • Laboratoire d'aérologie (LA)
      Lutetia Parisorum, Île-de-France, France
  • 2006
    • University of Grenoble
      Grenoble, Rhône-Alpes, France
  • 2005
    • Maastricht University
      Maestricht, Limburg, Netherlands
  • 2002
    • University of Bonn
      Bonn, North Rhine-Westphalia, Germany
  • 2000
    • The University of Manchester
      Manchester, England, United Kingdom
    • Hôpital Bicêtre (Hôpitaux Universitaires Paris-Sud)
      Lutetia Parisorum, Île-de-France, France
  • 1996
    • Centre Hospitalier Universitaire de Grenoble
      Grenoble, Rhône-Alpes, France
  • 1991–1993
    • Institut Pasteur
      Lutetia Parisorum, Île-de-France, France