Several reagents are available to perform activated partial thromboplastin time (APTT) that is a key test in routine haemostasis laboratories. However, the ability of APTT reagents to detect specific coagulation factor deficiencies may be affected by several variables, including the origin (human, animal or vegetable), composition, configuration of phospholipids and the type of surface activator. These variations in sensitivity explain why specialized haemostasis laboratories often use several different APTT reagents for specific and variable applications, i.e. control of heparin therapy, screening for lupus anticoagulant, evaluation of coagulation status before surgery and one-stage APTT-based assays for measurement of factor VIII (FVIII), factor IX (FIX), factor XI (FXI) and factor XII (FXII) plasma levels.We have recently tested the Actin FS Ò reagent (Dade Behring, Marburg, Germany) in our laboratory and recorded higher FIX activity levels (FIX:C) in several haemophilia B (HB) patients than those previously assayed with our usual reagent. We therefore initiated a multicentre study in a larger sample of patients to confirm these results and to identify the reasons explaining such discrepancies in the results obtained.Three hospital haematology laboratories participated in this study: Tours (central laboratory), Caen and Nantes. Blood samples were obtained from 40 patients previously diagnosed as having HB and not regularly treated with plasma-derived or recombinant factor IX (rFIX) concentrates. The basal FIX:C level in these patients was £1 IU dL )1 (n = 6), between 1 and 5 IU dL )1 (n = 10), or between 5 and 40 IU dL )1 (n = 24). FIX antigen levels (FIX:Ag) were also measured in these 40 untreated HB patients using Asserachrom Ò IX:Ag (Stago, Asnières, France), and the values obtained were compared with FIX:C levels. In 13 patients FIX:Ag levels were comparable with those of procoagulant activity (FIX:C/FIX:Ag >0.7), and these patients were defined as having a Ôtype 1Õ FIX deficiency. In contrast, the amount of FIX measured by immunological assay in the plasma from 27 HB patients was markedly higher than functional level. These patients therefore exhibited a FIX:C/FIX:Ag ratio lower than 0.7 and were defined as having a Ôtype 2Õ FIX deficiency.Factor IX:C level was measured by one-stage assay carried out on a STAR Analyzer (Stago) which is used in the majority of reference laboratories in France. All analyses were performed in duplicate on plasma aliquots which had been stored at )80°C after double centrifugation to ensure efficient platelet depletion and the same reagent batches were used in all three centres.Three APTT reagents were used: CKPrest Ò from Stago (rabbit brain thromboplastin + Kaolin), PTTA Ò from Stago (rabbit brain thromboplastin + silica) and Actin FS Ò from Dade Behring (soy phospholipids + ellagic acid). For each APTT reagent, calibration curves from 100 to 12.5 IU dL )1 were obtained by diluting standard human plasma (RKL) from 1/5 to 1/80 in FIX-deficient plasma (both reagents from Dade...

SummaryQuantification of lupus anticoagulant (LA) in clinical samples is hampered by the lack of a suitable standard of activity. We evaluated the use of mAbs displaying LA activity for this purpose. As most patient samples contain both β2Glycoprotein I (β2GP1) and prothrombin dependent LA, a combination of two mAbs, one of each specificity, was added to normal plasma in a concentration from 0 to 60 g/ml. Eight assay systems using different reagents and instruments were used. The calibration curves were linear for all but one, with marked differences between the responsiveness to each mAb. A panel of plasmas from 69 patients with persistent LA diagnosed using the SSCISTH criteria was tested. An antiphospholipid syndrome (APS) was present in 40, whereas 29 were asymptomatic. LA activities of individual plasmas varied between assays (p <10–4), but homogeneous subgroups were identified. In a majority of samples, LA activity displayed a prothrombin-dependent profile, with a variable contribution of β2GP1-dependent activity. The latter was associated to β2GP1 antibodies detected by solid-phase immunoassay. By using 3 dilute Russell viper venom time assays, higher LA titers were found in APS, compared to asymptomatic patients (p <0.05).

BackgroundPreeclampsia and coronary-artery disease share risk factors, suggesting common pathophysiological mechanisms. CX3CR1/CX3CL1 mediates leukocyte migration and adhesion and has been implicated in the pathophysiology of several inflammatory diseases. M280/I249 variants of CX3CR1 are associated with an atheroprotective effect and reduced endothelial dysfunction. The aim of this study was to search for an association between V249I and T280M polymorphisms of CX3CR1, preeclampsia and endothelial dysfunction.Methodology/Principal FindingsWe explored these polymorphisms with real-time polymerase chain reaction in a case-control study (184 white women with preeclampsia and 184 matched normotensive pregnant women). Endothelial dysfunction biomarkers including von Willebrand factor, VCAM-1 and thrombomodulin, as well as the soluble form of CX3CL1 were measured by enzyme-linked immunosorbent assays (ELISA). The I249 and M280 alleles were associated neither with preeclampsia, nor with its more severe form or with endothelial injury. In contrast, we found a trend toward increased CX3CL1 levels in preeclampsia patients, especially in early-onset- preeclampsia as compared to its level in later-onset- preeclampsia.Conclusions/SignificanceThis is the first study to characterize the CX3CR1 gene polymorphisms in patients with preeclampsia. We found no differences in genotype or haplotype frequencies between patients with PE and normal pregnancies, suggesting that maternal CX3CR1 V249I and T280M polymorphisms do not increase susceptibility to preeclampsia. Further studies should be performed to directly evaluate the pathophysiological role of CX3CL1, a molecule abundantly expressed in endometrium, which has been shown to stimulate human trophoblast migration.

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Introduction: Cerebral venous thrombosis (CVT) is a rare disease with highly variable clinical presentation and outcome. Etiological assessment may be negative. The clinical and radiological presentation and evolution can be highly variable. The mechanisms involved in this variability remain unknown.Objective: The aim of this multicenter French study registered on ClinicalTrials.gov (NCT02013635) was therefore to prospectively recruit a cohort of patients with cerebral venous thrombosis (FPCCVT) in order to study thrombin generation and clot degradation, and to evaluate their influence on clinical radiological characteristics. The first part of the study was to compare our cohort with a reference cohort.Methods: This prospective, multicenter, French study was conducted from July 2011 to September 2016. Consecutive patients (aged &gt;15 years) referred to the stroke units of 21 French centers and who had a diagnosis of symptomatic CVT were included. All patients gave their written informed consent. The diagnosis of CVT had to be confirmed by imaging. Clinical, radiological, biological, and etiological characteristics were recorded at baseline, at acute phase, at 3 months and at last follow-up visit. Thrombophilia screening and the choice of treatment were performed by the attending physician. All data were compared with data from the International Study on CVT published by Ferro et al.Results: Two hundred thirty-one patients were included: 117 (50.6%) had isolated intracranial hypertension, 96 (41.5%) had focal syndrome. During hospitalization, 229 (99.1%) patients received anticoagulant treatment. Median length of hospital stay was 10 days. Five patients died during hospitalization (2.2%). At 3 months, 216 patients (97.0%) had follow-up with neurological data based on an outpatient visit. The mean duration of antithrombotic treatment was 9 months, and the mean time to last follow-up was 10.5 months. At the end of follow-up, eight patients had died, and 26 patients were lost to follow-up. At least one risk factor was identified in 200 patients.Conclusions: We demonstrated that the FPCCVT cohort had radiological, biological, and etiological characteristics similar to the historical ISCVT cohort. Nevertheless, the initial clinical presentation was less severe in our study probably due to an improvement in diagnostic methods between the two studies.