The use of 1E12, a monoclonal anti-platelet factor 4 antibody, to improve the diagnosis of vaccine-induced immune thrombotic thrombocytopenia.

BACKGROUND: Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a complication of adenoviral-based vaccine against SARS-CoV-2 due to prothrombotic immunoglobulin (Ig) G antibodies to platelet factor 4 (PF4) and may be difficult to distinguish from heparin-induced thrombocytopenia (HIT) in patients treated with heparin. OBJECTIVES: We assessed the usefulness of competitive anti-PF4 enzyme immunoassays (EIAs) in this context. METHODS: The ability of F(ab')2 fragments of 1E12, 1C12, and 2E1, 3 monoclonal anti-PF4 antibodies, to inhibit the binding of human VITT or HIT antibodies to PF4 was evaluated using EIAs. Alanine-scanning mutagenesis was performed to define the amino acids involved in the interactions between the monoclonal antibodies and PF4. RESULTS: A strong inhibition of VITT IgG binding to PF4 was measured with 1E12 (median inhibition, 93%; n = 8), whereas it had no effect on the binding of HIT antibodies (median, 6%; n = 8). In contrast, 1C12 and 2E1 inhibited VITT (median, 74% and 76%, respectively) and HIT antibodies (median, 68% and 53%, respectively) binding to PF4. When a competitive anti-PF4 EIA was performed with 1E12 for 19 additional VITT samples, it strongly inhibited IgG binding to PF4, except for 1 patient, who had actually developed HIT according to the clinical history. Epitope mapping showed that 1E12 interacts with 5 key amino acids on PF4, of which 4 are also required for the binding of human VITT antibodies, thus explaining the competitive inhibition. CONCLUSION: A simple competitive anti-PF4 EIA with 1E12 could help confirm VITT diagnosis and distinguish it from HIT in patients when both diagnoses are possible.

Thrombin Generation Assay in Antiphospholipid Antibodies Positive Subjects as a Personalized Thrombotic Risk Assessment: State of the Art and Perspectives.

PURPOSE OF THE REVIEW: Thrombotic risk assessment in antiphospholipid positive (aPL +) subjects is a major challenge, and the study of in vitro thrombin generation (thrombin generation assays (TGA)) could provide useful information. Activated protein C (APC) sensitivity is involved in thrombotic events in antiphospholipid syndrome patients. We summarized methods used to assess APC sensitivity with TGA and evaluated the prognostic role of APC resistance through literature search. RECENT FINDINGS: APC resistance induced by aPL is a complex pathway. Several cross-sectional studies assessed APC sensitivity to understand thrombotic event mechanisms in aPL + subjects. Only one prospective cohort had investigated the prognostic impact of APC resistance in aPL + subjects, with a positive and significant correlation between APC sensitivity and the risk of thrombosis during the follow up (hazard ratio, 6.07 [95% CI, 1.69-21.87]). APC resistance assessed with TGA could be associated with thrombotic events in aPL + subjects.

C-reactive protein and D-dimer in cerebral vein thrombosis: Relation to clinical and imaging characteristics as well as outcomes in a French cohort study.

Introduction: Cerebral venous sinus thrombosis (CVST) is a rare disease with highly variable clinical presentation and outcomes. Clinical studies suggest a role of inflammation and coagulation in CVST outcomes. The aim of this study was to investigate the association of inflammation and hypercoagulability biomarkers with CVST clinical manifestations and prognosis. Methods: This prospective multicenter study was conducted from July 2011 to September 2016. Consecutive patients referred to 21 French stroke units and who had a diagnosis of symptomatic CVST were included. High-sensitivity C-reactive protein (hs-CRP), neutrophil-to-lymphocyte ratio (NLR), D-dimer, and thrombin generation using calibrated automated thrombogram system were measured at different time points until 1 month after anticoagulant therapy discontinuation. Results: Two hundred thirty-one patients were included. Eight patients died, of whom 5 during hospitalization. The day 0 hs-CRP levels, NLR, and D-dimer were higher in patients with initial consciousness disturbance than in those without (hs-CRP: 10.2 mg/L [3.6-25.5] vs 23.7 mg/L [4.8-60.0], respectively; NLR: 3.51 [2.15-5.88] vs 4.78 [3.10-9.59], respectively; D-dimer: 950 µg/L [520-2075] vs 1220 µg/L [950-2445], respectively). Patients with ischemic parenchymal lesions (n = 31) had a higher endogenous thrombin potential5pM than those with hemorrhagic parenchymal lesions (n = 31): 2025 nM min (1646-2441) vs 1629 nM min (1371-2090), respectively (P = .0082). Using unadjusted logistic regression with values >75th percentile, day 0 hs-CRP levels of >29.7 mg/L (odds ratio, 10.76 [1.55-140.4]; P = .037) and day 5 D-dimer levels of >1060 mg/L (odds ratio, 14.63 [2.28-179.9]; P = .010) were associated with death occurrence. Conclusion: Two widely available biomarkers measured upon admission, especially hs-CRP, could help predict bad prognosis in CVST in addition to patient characteristics. These results need to be validated in other cohorts.

Identification of Heparin-Induced Thrombocytopenia in Surgical Critically Ill Patients by Using the HIT Expert Probability Score: An Observational Pilot Study.

Background: Heparin-induced thrombocytopenia (HIT) remains a challenging diagnosis especially in surgical intensive care unit (SICU) patients. The aim of the study was to evaluate for the first time the diagnostic accuracy of the HIT Expert Probability (HEP) score in the early identification of HIT in SICU patients. Methods: The HEP and 4Ts scores were calculated in all patients with suspected HIT during their stay in our SICU. The diagnosis of HIT was finally confirmed (HIT+ group) or excluded (HIT− group) by an independent committee blinded to the HEP and 4Ts score values. The primary outcome was the sensitivity and specificity of a HEP score ≥ 5 for the diagnosis of HIT. The secondary outcome was the area under the ROC curve (AUC) of the HEP and 4Ts scores in the diagnosis of HIT. Results: Respectively 6 and 113 patients were included in the HIT+ and HIT− groups. A HEP score value ≥ 5 had a sensitivity (95% confidence interval (95% CI)) of 1.00 (0.55−1.00), and a specificity (95% CI) of 0.92 (0.86−0.96). The AUC (95% CI) was significantly higher for the HEP score versus for the 4Ts score (0.967 (0.922−1.000) versus 0.707 (0.449−0.965); p = 0.035). Conclusions: A HEP score value < 5 could be helpful to rule out HIT in SICU patients.

Cerebral Venous Thrombosis: Clinical, Radiological, Biological, and Etiological Characteristics of a French Prospective Cohort (FPCCVT)-Comparison With ISCVT Cohort.

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 >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.

Small Annexin V-Positive Platelet-Derived Microvesicles Affect Prognosis in Cirrhosis: A Longitudinal Study.

INTRODUCTION: Microvesicles (MVs) with procoagulant properties may favor liver parenchymal extinction, then cirrhosis-related complications and mortality. In a longitudinal cohort of cirrhotic patients, we measured plasma levels of platelet-derived MVs (PMVs), endothelial-derived MVs, and red blood cell-derived MVs, expressing phosphatidylserine (annexin V-positive [AV+]) or not, and evaluated their impact on Model for End-Stage Liver Disease (MELD) score and transplant-free survival. METHODS: MVs were quantified using flow cytometry in plasma from 90 noninfected cirrhotic patients and 10 healthy volunteers matched for age and sex. Impact of plasma microvesicle levels on 6-month transplant-free survival was assessed using log-rank tests and logistic regression. RESULTS: Microvesicle levels, mostly platelet-derived, were 2.5-fold higher in healthy volunteers compared with cirrhotic patients. Circulating small AV+ PMV levels were lower in cirrhotic patients (P = 0.014) and inversely correlated with MELD scores (R = -0.28; P = 0.0065). During 1-year follow-up, 8 patients died and 7 underwent liver transplantation. In the remaining patients, circulating microvesicle levels did not change significantly. Six-month transplant-free survival was lower in patients with low baseline small AV+ PMV levels (72.6% vs 96.2%; P = 0.0007). In multivariate analyses adjusted for age, ascites, esophageal varices, encephalopathy, clinical decompensation, total platelet counts, MELD score, and/or Child-Pugh C stage, patients with lower small AV+ PMV levels had a significant 5- to 8-fold higher risk of 6-month death or liver transplant. Other PMV levels did not impact on survival. DISCUSSION: Decreased circulating small AV+ PMV levels are associated with significantly lower transplant-free survival in cirrhotic patients independently of MELD score and platelet counts.

Severe thrombophilia in a factor V-deficient patient homozygous for the Ala2086Asp mutation (FV Besançon).

BACKGROUND: Coagulation factor V (FV), present in plasma and platelets, has both pro- and anticoagulant functions. OBJECTIVE: We investigated an FV-deficient patient (FV:C 3%, FV:Ag 4%) paradoxically presenting with recurrent venous thrombosis (11 events) instead of bleeding. METHODS/RESULTS: Thrombophilia screening revealed only heterozygosity for the F2 20210G>A mutation. Although thrombin generation in the patient's platelet-poor plasma was suggestive of a hypocoagulable state, thrombin generation in the patient's platelet-rich plasma (PRP) was higher than in control PRP and extremely resistant to activated protein C (APC). This was partially attributable to the complete abolition of the APC-cofactor activity of FV and a marked reduction of plasma tissue factor pathway inhibitor antigen and activity. The patient was homozygous for a novel missense mutation (Ala2086Asp, FVBesançon ) that favors a "closed conformation" of the C2 domain, predicting impaired binding of FV(a) to phospholipids. Recombinant FVBesançon was hardly secreted, indicating that this mutation is responsible for the patient's FV deficiency. Model system experiments performed using highly diluted plasma as a source of FV showed that, compared with normal FVa, FVaBesançon has slightly (≤1.5-fold) unfavorable kinetic parameters (Km , Vmax ) of prothrombin activation, but also a lower rate of APC-catalyzed inactivation in the presence of protein S. CONCLUSIONS: FVBesançon induces a hypercoagulable state via quantitative (markedly decreased FV level) and qualitative (phospholipid-binding defect) effects that affect anticoagulant pathways (anticoagulant activities of FV, FVa inactivation, tissue factor pathway inhibitor α level) more strongly than the prothrombinase activity of FVa. A possible specific role of platelet FV cannot be excluded.

Comparison of different activators of coagulation by turbidity analysis of hereditary dysfibrinogenemia and controls.

Turbidity analysis is widely used as a quantitative technique in hereditary dysfibrinogenemia. We aimed to compare several coagulation triggers in hereditary dysfibrinogenemia and control plasmas. We included 20 patients with hereditary dysfibrinogenemia, 19 with hotspot mutations Aα Arg35His (n = 9), Aα Arg35Cys (n = 2), γ Arg301His (n = 6), γ Arg301Cys (n = 2), and one with Aα Phe27Tyr, and a commercial pooled normal plasma. Fibrin polymerization was activated by bovine or human thrombin or tissue factor (TF), in the presence or absence of tissue type plasminogen activator. The lag time (min), slope (mOD/s), maximum absorbance (MaxAbs, mOD), and area under the curve (AUCp, OD s) were calculated from the fibrin polymerization curves and the time for 50% clot degradation (T50, min), AUCf (OD s) and the overall fibrinolytic potential from fibrinolysis curves. The lag time was significantly shorter and AUC increased in Aα Arg35His patients with bovine thrombin as compared with human thrombin. The MaxAbs and AUCp were significantly higher in γArg301His patients with bovine thrombin compared with human thrombin. Fibrin polymerization parameters of patients' samples were closer to those of control when assessed with TF compared with both human and bovine thrombin. T50 and overall fibrinolytic potential were similar in all samples regardless of the coagulation trigger used, however, with TF the AUCf of Aα Arg35His and γ Arg301His groups were significantly decreased compared with control. Bovine and human thrombin cannot be used equally for studying fibrin polymerization in hotspot hereditary dysfibrinogenemia or control plasmas.

Effectiveness and safety of hFVIII/VWF concentrate (Voncento®) in patients with inherited von Willebrand disease requiring surgical procedures: the OPALE multicentre observational study.

BACKGROUND: In patients with moderate to severe qualitative and quantitative von Willebrand disease (VWD), even minor surgical procedures can be associated with a risk of life-threatening bleeding. Treatment strategies vary according to the levels of von Willebrand factor (VWF) and Factor VIII (FVIII). The aim of this study was to evaluate the effectiveness and the safety of Voncento® (CSL Behring, Marburg, Germany), a plasma-derived FVIII/VWF concentrate (ratio 1:2.4), during surgeries performed in patients with inherited VWD. MATERIALS AND METHODS: The OPALE study, a French multicentre observational study, was carried out from May 2016 to May 2019. It evaluated and analysed patients with inherited VWD (any type) requiring treatment with Voncento® who underwent surgery. RESULTS: In total, 92 patients were enrolled, and 66 patients underwent 100 surgical procedures: 69 minor and 31 major surgeries conducted in 30 patients with type 1, 50 patients with type 2, and 20 patients with type 3 VWD. During minor surgeries, the median number of infusions was one (range: 1-9), the pre-operative loading dose was 41 IU VWF:RCo kg-1 (range: 18-147), and the total dose was 63 (range: 18-594). During major surgeries, the number of infusions was 4 (range: 1-23), the pre-operative loading dose was 43 (range: 25-66) IU VWF: RCo kg-1, and the total dose was 155 (range: 40-575). The median FVIII:C levels ranged from 78 to 165 IU dL-1 during 5 days after minor surgeries and from 86 and 167 IU dL-1 during 11 days after major surgeries. VW:RCo levels ranged between 35 and 65 IU dL-1 and between 34 and 76 IU dL-1 after minor and major surgeries, respectively. The overall clinical effectiveness was qualified as "excellent" or "good" in 99% of patients. No thrombotic events related to Voncento® were recorded. DISCUSSION: The present study suggests that Voncento® is an effective and well-tolerated therapy for the peri-operative management of patients with all VWD types.

Assessment of Shear-Dependent Kinetics of Primary Haemostasis With a Microfluidic Acoustic Biosensor.

Primary haemostasis is a complex dynamic process, which involves in-flow interactions between platelets and sub-endothelial matrix at the area of the damaged vessel wall. It results in a first haemostatic plug, which stops bleeding, before coagulation ensues and consolidates it. The diagnosis of primary haemostasis defect would benefit from evaluation of the whole sequence of mechanisms involved in platelet plug formation in flow. This work proposes a new approach that is based on characterization of the shear-dependent kinetics that enables the evaluation of the early stages of primary haemostasis. We used a label-free method with a quartz crystal microbalance (QCM) biosensor to measure the platelet deposits over time onto covalently immobilized type I fibrillar collagen. We defined three metrics: total frequency shift, lag time, and growth rate. The measurement was completed at four predefined shear rates prevailing in small vessels (500, 770, 1000 and 1500 s-1) during five minutes of perfusion with anticoagulated normal whole blood. The rate of the frequency shift over the first five minutes was strongly influenced by shear rate conditions, presenting a maximum around 770 s-1, and varying by a factor larger than three in the studied shear rate range. To validate the biosensor signal, the total frequency shift was compared to results obtained by atomic force microscopy (AFM) on final platelet deposits. The results show that shear-dependent kinetic assays are promising as an advanced method for screening of primary haemostasis.

Processing methods and storage duration impact extracellular vesicle counts in red blood cell units.

Extracellular vesicles (EVs) are active components of red blood cell (RBC) concentrates and may be associated with beneficial and adverse effects of transfusion. Elucidating controllable factors associated with EV release in RBC products is thus important to better manage the quality and properties of RBC units. Erythrocyte-derived EVs (EEVs) and platelet-derived EVs (PEVs) were counted in 1226 RBC units (administered to 280 patients) using a standardized cytometry-based method. EV size and CD47 and annexin V expression were also measured. The effects of donor characteristics, processing methods, and storage duration on EV counts were analyzed by using standard comparison tests, and analysis of covariance was used to determine factors independently associated with EV counts. PEV as well as EEV counts were higher in whole-blood-filtered RBC units compared with RBC-filtered units; PEV counts were associated with filter type (higher with filters associated with higher residual platelets), and CD47 expression was higher on EEVs in RBC units stored longer. Multivariate analysis showed that EEV counts were strongly associated with filter type (P < .0001), preparation, and storage time (+25.4 EEV/µL per day [P = .01] and +42.4 EEV/µL per day [P < .0001], respectively). The only independent factor associated with PEV counts was the residual platelet count in the unit (+67.1 PEV/µL; P < .0001). Overall, processing methods have an impact on EV counts and characteristics, leading to large variations in EV quantities transfused into patients. RBC unit processing methods might be standardized to control the EV content of RBC units if any impacts on patient outcomes can be confirmed. The IMIB (Impact of Microparticles in Blood) study is ancillary to the French ABLE (Age of Transfused Blood in Critically Ill Adults) trial (ISRCTN44878718).

Elevated D-dimers and lack of anticoagulation predict PE in severe COVID-19 patients.

BACKGROUND: Coronavirus disease 2019 (COVID-19) may predispose to venous thromboembolism. We determined factors independently associated with computed tomography pulmonary angiography (CTPA)-confirmed pulmonary embolism (PE) in hospitalised severe COVID-19 patients. METHODS: Among all (n=349) patients hospitalised for COVID-19 in a university hospital in a French region with a high rate of COVID-19, we analysed patients who underwent CTPA for clinical signs of severe disease (oxygen saturation measured by pulse oximetry ≤93% or breathing rate ≥30 breaths·min-1) or rapid clinical worsening. Multivariable analysis was performed using Firth penalised maximum likelihood estimates. RESULTS: 162 (46.4%) patients underwent CTPA (mean±sd age 65.6±13.0 years; 67.3% male (95% CI 59.5-75.5%). PE was diagnosed in 44 (27.2%) patients. Most PEs were segmental and the rate of PE-related right ventricular dysfunction was 15.9%. By multivariable analysis, the only two significant predictors of CTPA-confirmed PE were D-dimer level and the lack of any anticoagulant therapy (OR 4.0 (95% CI 2.4-6.7) per additional quartile and OR 4.5 (95% CI 1.1-7.4), respectively). Receiver operating characteristic curve analysis identified a D-dimer cut-off value of 2590 ng·mL-1 to best predict occurrence of PE (area under the curve 0.88, p<0.001, sensitivity 83.3%, specificity 83.8%). D-dimer level >2590 ng·mL-1 was associated with a 17-fold increase in the adjusted risk of PE. CONCLUSION: Elevated D-dimers (>2590 ng·mL-1) and absence of anticoagulant therapy predict PE in hospitalised COVID-19 patients with clinical signs of severity. These data strengthen the evidence base in favour of systematic anticoagulation, and suggest wider use of D-dimer guided CTPA to screen for PE in acutely ill hospitalised patients with COVID-19.

Antiplatelet Antibodies Do Not Predict the Response to Intravenous Immunoglobulins during Immune Thrombocytopenia.

Immune thrombocytopenia (ITP) is a rare autoimmune disease due to autoantibodies targeting platelet glycoproteins (GP). The mechanism of platelet destruction could differ depending on the specificity of antiplatelet antibodies: anti-GPIIb/IIIa antibodies lead to phagocytosis by splenic macrophages, in a Fcγ receptor (FcγR)-dependent manner while anti-GPIb/IX antibodies induce platelet desialylation leading to their destruction by hepatocytes after binding to the Ashwell-Morell receptor, in a FcγR-independent manner. Considering the FcγR-dependent mechanism of action of intravenous immunoglobulins (IVIg), we assumed that the response to IVIg could be less efficient in the presence of anti-GPIb/IX antibodies. We conducted a multicentric, retrospective study including all adult ITP patients treated with IVIg who had antiplatelet antibodies detected between January 2013 and October 2017. Among the 609 identified, 69 patients were included: 17 had anti-GPIb/IX antibodies and 33 had anti-GPIIb/IIIa antibodies. The response to IVIg was not different between the patients with or without anti-GPIb/IX (88.2% vs. 73.1%). The response to IVIg was better in the case of newly diagnosed ITP (odds ratio (OR) = 5.4 (1.2-24.7)) and in presence of anti-GPIIb/IIIa (OR = 4.82 (1.08-21.5)), while secondary ITP had a poor response (OR = 0.1 (0.02-0.64)). In clinical practice, the determination of antiplatelet antibodies is therefore of little value to predict the response to IVIg.

Circulating levels of 3-hydroxymyristate, a direct quantification of endotoxaemia in noninfected cirrhotic patients.

BACKGROUND & AIMS: The quantification of lipopolysaccharide (LPS) in biological fluids is challenging. We aimed to measure plasma LPS concentration using a new method of direct quantification of 3-hydroxymyristate (3-HM), a lipid component of LPS, and to evaluate correlations between 3-HM and markers of liver function, endothelial activation, portal hypertension and enterocyte damage. METHODS: Plasma from 90 noninfected cirrhotic patients (30 Child-Pugh [CP]-A, 30 CP-B, 30 CP-C) was prospectively collected. The concentration of 3-HM was determined by high-performance liquid chromatography coupled with mass spectrometry. RESULTS: 3-HM levels were higher in CP-C patients (CP-A/CP-B/CP-C: 68/70/103 ng/mL, P = 0.005). Patients with severe acute alcoholic hepatitis (n = 16; 113 vs 74 ng/mL, P = 0.012), diabetic patients (n = 22; 99 vs 70 ng/mL, P = 0.028) and those not receiving beta blockers (n = 44; 98 vs 72 ng/mL, P = 0.034) had higher levels of 3-HM. We observed a trend towards higher baseline levels of 3-HM in patients with hepatic encephalopathy (n = 7; 144 vs 76 ng/mL, P = 0.45) or SIRS (n = 10; 106 vs 75 ng/mL, P = 0.114). In multivariate analysis, high levels of 3-HM were associated with CP (OR = 4.39; 95%CI = 1.79-10.76) or MELD (OR = 8.24; 95%CI = 3.19-21.32) scores. Patients dying from liver insufficiency (n = 6) during a 12-month follow-up had higher baseline levels of 3-HM (106 vs 75 ng/mL, P = 0.089). CONCLUSIONS: In noninfected cirrhotic patients, 3-HM arises more frequently with impairment of liver function, heavy alcohol consumption, diabetic status, nonuse of beta blockers and a trend towards poorer outcome is also observed. The direct mass measurement of LPS using 3-HM appears reliable to detect transient endotoxaemia and promising to manage the follow-up of cirrhotic patients.

In vitro quality of amotosalen-UVA pathogen-inactivated mini-pool plasma prepared from whole blood stored overnight.

BACKGROUND AND OBJECTIVES: Small batch-pooled (mini-pool) whole blood (WB)-derived plasma could be an alternative cost-effective source of therapeutic plasma (TP), but carries an increased risk of transfusion-transmitted infection due to exposure of the recipient to several donors. This risk can be mitigated by inactivation of pathogens susceptible to the amotosalen-UVA (AUVA)-treatment. We evaluated the conservation of coagulation factors in AUVA-plasma prepared from WB stored overnight under routine operating conditions, to determine its therapeutic efficacy. Thrombin generation (TG) by the AUVA-plasma was used to provide an integrated measure of the hemostatic capacity. MATERIALS AND METHODS: WB-donations (~450 ml) stored overnight were processed to prepare five leucocyte-depleted plasma mini-pools (1300 ml), which were divided into two parts and treated with AUVA. Each mini-pool yielded six AUVA-plasma units (200 ml) which were frozen (-25°C) within 19 h of WB-collection. Their hemostatic quality was evaluated before and after treatment for up to 12 months of storage. RESULTS: Immediately after AUVA-treatment, the regulatory criteria for FVIII activity and fibrinogen content were met. As compared to untreated plasma there was a reduction in fibrinogen (14%), FV (9%), FVII (25%) and FVIII (32%). However, TG was similar in treated and untreated plasma at all-time-points. CONCLUSIONS: Frozen WB-derived AUVA-plasma prepared from mini-pools within 19 h of WB-collection met the quality standards required for TP and retained hemostatic capacity for up to 12 months. This product could provide a cost-effective convenient substitute for apheresis plasma.

Determinants of adherence and consequences of the transition from adolescence to adulthood among young people with severe haemophilia (TRANSHEMO): study protocol for a multicentric French national observational cross-sectional study.

INTRODUCTION: Severe haemophilia is a rare disease characterised by spontaneous bleeding from early childhood, which may lead to various complications, especially in joints. It is nowadays possible to avoid these complications thanks to substitutive therapies for which the issue of adherence is major. The transition from adolescence to adulthood in young people with severe haemophilia is a critical period as it is associated with a high risk of lack of adherence to healthcare, which might have serious consequences on daily activities and on quality of life. METHODS AND ANALYSIS: We present the protocol for a cross-sectional, observational, multicentric study to assess the differences between adolescents and young adults with severe haemophilia in France through the transition process, especially on adherence to healthcare. This study is based on a mixed methods design, with two complementary and consecutive phases, comparing data from a group of adolescents (aged 14-17 years) with those from a group of young adults (aged 20-29 years). The quantitative phase focuses on the determinants (medical, organisational, sociodemographic and social and psychosocial and behavioural factors) of adherence to healthcare (considered as a marker of the success of transition). The qualitative phase explores participants' views in more depth to explain and refine the results from the quantitative phase. Eligible patients are contacted by the various Haemophilia Treatment Centres participating in the French national registry FranceCoag. ETHICS AND DISSEMINATION: The study was approved by the French Ethics Committee and by the French National Agency for Medicines and Health Products Safety (number: 2016-A01034-47). Study findings will be disseminated to the scientific and medical community in peer-reviewed journals and presented at scientific meetings. Results will be popularised to be communicated via the French association for people with haemophilia to participants and to the general public. TRIAL REGISTRATION NUMBER: NCT02866526; Pre-results.

Increased levels of circulating platelet-derived microparticles are associated with metastatic cutaneous melanoma.

We investigated the plasma levels of PMPs in patients with 45 stage III and 45 stage IV melanoma. PMPs were characterised by flow cytometry and their thrombogenic activity. We also investigated the link between PMPs circulating levels and tumor burden. The circulating levels of PMPs were significantly higher in stage IV (8500 µL-1 ) than in patients with stage III (2041 µL-1 ) melanoma (P=.0001). We calculated a highly specific (93.3%) and predictive (91.7%) cut-off value (5311 µL-1 ) allowing the distinction between high-risk stage III and metastatic stage IV melanoma. The thrombogenic activity of PMPs was significantly higher in patients with stage IV melanoma (clotting time: 40.7 second vs 65 second, P=.0001). There was no significant association between the radiological tumoral syndrome and the plasma level of PMPs. Our data suggest the role of PMPs in metastatic progression of melanoma.