Delayed Plasma Clot Lysis in Adult Patients with Primary Immune Thrombocytopenia (ITP)

Introduction: Primary immune thrombocytopenia (ITP) is an orphan disease characterized by very low platelet counts. Patients have heterogeneous bleeding phenotypes, which are not only determined by platelet counts, also a paradoxically increased thrombotic risk has been observed. Aim: To investigate, whether the fibrinolysis inhibitors plasminogen activator inhibitor-1 (PAI-1) and α2-antiplasmin are associated with impaired plasma clot lysis in primary ITP patients in comparison to non-immunologic thrombocytopenic controls (TPC) and healthy controls (HC). Furthermore, associations with bleeding severity and previous thrombotic events were investigated. Methods: Patients from the Vienna ITP biobank (EC 1843/2016), a multi-centric study including adult patients with primary ITP were investigated and compared to age- and sex-matched control groups: TPC with thrombocytopenia after chemotherapy and HC. Informed consent was obtained from all individuals before study inclusion. A clot formation and lysis assay (CLA) was performed according to the recommendations of the ISTH SSC. Platelet poor plasma samples were measured in duplicates for each patient and control. PAI-1 (PAI-1 Actibind ELISA, Technoclone, Vienna, Austria) and α2-antiplasmin by the chromogenic STA Stachrom antiplasmin assay (Diagnostic Stago, Asnieres, France) were measured. Bleeding severity was measured using the ITP-specific ITP-ISTH BAT (Rodeghiero et al. 2013). Results: In total, 37 primary ITP patients, 18 TPC and 156 healthy controls were analyzed (Table 1). Primary ITP patients had a higher BMI than HC. Bleeding severity was higher and more ITP patients had a thrombosis history compared to HC, whereas there was no difference in comparison to TPC. PAI-1 activity was highest in ITP patients, with a statistically significant difference in comparison to HC. α2-antiplasmin activity was higher in ITP patients than in TPC, whereas there was no difference in comparison to HC. After adjustment for sex, age, BMI and fibrinogen, primary ITP patients had a reduced clot formation rate (V max) and significantly delayed plasma clot lysis compared to TPC and HC (Table 2). Also, the lag phase and time to peak absorbance (TTP) were prolonged with a significant difference in comparison to HC. To investigate outliers of PAI-1 and α2-antiplasmin, we calculated cut-offs at the 75 th percentile of healthy controls (PAI-1: ≥ 3.1 U/mL, α2-antiplasmin: ≥ 107.0 %). 14 (37.8 %) ITP patients had PAI-1 levels and 10 (27.0 %) ITP patients had α2-antiplasmin activity above the cut-off. ITP patients with high PAI-1 levels had mildly delayed clot lysis in comparison to those below with a significantly lower maximal lysis rate (mLR). ITP patients with α2-antiplasmin activity above the cut-off had a significantly shorter lag phase, faster V max and shorter TTP than patients below the cut-off, whereas there was no difference in clot lysis. No differences between ITP patients above or below the respective cut-offs of PAI-1 and α2-antiplasmin regarding their bleeding severity and thrombosis incidence were observed (Table 3). Conclusion: Primary ITP patients have a tendency towards increased PAI-1 activity, which is associated with considerably delayed plasma clot lysis. Albeit an association with the bleeding score could not be identified, this impaired lysis could be seen as a counter-regulation and at least contribute to the relatively mild bleeding tendency in patients with ITP. Figure 1 Figure 1. Disclosures Pabinger: CSL Behring: Consultancy, Honoraria, Research Funding; NovoNordisk: Consultancy, Research Funding; Bayer: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Daiichi Sanchyo: Consultancy, Honoraria; Alexion: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria.

USP Standardized Mixtures of Bovine, Ovine and Porcine Heparin Exhibit Comparable Biologic Effects to Referenced Single Sourced Heparins and May be Interchangeable,

Introduction: Unfractionated heparin (UFH) is the first line anticoagulant for the management of medical indications. UFH complexes with antithrombin to produce strong inhibition of thrombin and factor Xa. The UFHs are standardized using USP compliant amidolytic anti-Xa and IIa methods in defined conditions. Clinically used UFH is solely sourced from porcine mucosal tissue. Because of the shortage of porcine tissue and the African Swine Fever, the supply chain of this anticoagulant is compromised. Thus, there is a need for resourcing of this anticoagulant. Bovine and ovine mucosal sources represent alternate material for production of UFH. Previous studies have shown that bovine and ovine UFH exhibit anticoagulant effects which can be standardized by using the USP method. Additionally, the standardized heparins from various sources can be blended and their potency can be adjusted to exhibit comparable effects as the single sourced UFH. The purpose of this study is to evaluate the pharmacologic profile of the blended heparin and compare these activities to that of the single sourced porcine, ovine and bovine heparins. Methods: Two groups of heparins were evaluated in this study, porcine, ovine, bovine, and the blended heparin in gravimetric measurements (ug/ml) and these same four in potency adjusted measurements (U/ml). The pharmacologic profiles of the heparins in this study were investigated via global anticoagulant assays and anti-protease assays performed in plasma. Clot based assays such as the activated partial thromboplastin time (aPTT) and thrombin time (TT) were used to study the anticoagulant effects of the single source and blended heparins. The amidolytic anti-Xa and IIa assays were used to assess the inhibitory effects of these heparins on these proteases. USP compliant anti-Xa and IIa assays were used to determine potencies of the various heparins. Protamine sulfate (PS) neutralization studies were performed to evaluate the reversal of anticoagulant effects in each of the heparins. Results: The aPTT assay showed that at final concentrations of 5 ug/ml and 2.5 ug/ml porcine heparin significantly (p < .01) prolonged the aPTT compared to ovine, bovine, and blended heparins. When studied with potency adjusted heparins, all heparins demonstrated comparable aPTT values at all concentrations (U/ml). The TT assay showed that porcine and ovine heparins prolonged the TT at 1.25 ug/ml compared to bovine and blended heparins. When studied with potency adjusted heparins, all heparins demonstrated comparable TT values at all concentrations (U/ml). The anti-Xa assay showed that at all final concentrations between 10 ug/ml and 0.625 ug/ml porcine, ovine, and blended heparins produced significantly (p <.001) stronger Xa inhibition than bovine heparin. When studied with potency adjusted heparins, all heparins demonstrated comparable anti-Xa inhibition at all concentrations (U/ml). The anti-IIa assay showed that at final concentrations 2.5 ug/ml, 1.25 ug/ml, and 0.625 ug/ml porcine and ovine heparins produced significantly (p < .05) stronger IIa inhibition than bovine heparin. When studied with potency adjusted heparins, all heparins demonstrated comparable anti-IIa inhibition at all concentrations (U/ml). The USP compliant anti-Xa assay with gravimetric heparins showed potencies of 201, 201, 150, and 184 U for porcine, ovine, bovine, and blended heparins respectively. The USP compliant anti-Xa assay with potency adjusted heparins showed comparable potencies for all four heparins. The USP compliant anti-IIa assay with gravimetric heparins showed potencies of 204, 196, 127, and 167 U for porcine, ovine, bovine, and blended heparins respectively. The USP compliant anti-IIa assay with potency adjusted heparins showed comparable potencies for all four heparins. The protamine sulfate neutralization studies demonstrated complete neutralization at all concentrations for all of the potency adjusted heparins in the aPTT, TT, anti-Xa, and anti-IIa assays. Conclusion: These studies support the hypothesis that a blended heparin product from bovine, ovine, and porcine tissue, when standardized in USP unit-equivalent proportions, exhibits a comparable anticoagulant profile to the single species heparins. These findings suggest that there is a potential for development of blended heparin to stabilize supply chain of this important anticoagulant and warrant clinical validation. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Accelerated fibrin clot degradation is associated with arterial thromboembolism in patients following venous thrombosis: a cohort study

Several lines of evidence have suggested that patients following venous thromboembolism (VTE) are at higher risk of arterial thromboembolism (ATE). Prothrombotic fibrin clot characteristics were reported in individuals with cardiovascular risk factors. We investigated whether specific fibrin clot properties measured after 3–4 months of anticoagulation characterize VTE patients with subsequent ATE. We enrolled 320 patients following VTE aged below 70 years (median age, 46). Ten patients were lost to follow-up. ATE occurred in 21 individuals after a median 54 (31–68) months during a follow-up of 87.5 months (incidence 0.94%; 95% confidence interval [CI], 0.59–1.4 per patient-year). Patients with ATE had faster fibrin clot degradation, reflected by maximum rate of D-dimer increase during plasma clot lysis induced by tissue-type plasminogen activator (D-Drate) at baseline. Clot permeability, turbidimetric variables, clot lysis time, and thrombin generation were unrelated to ATE. Univariable Cox proportional hazards analysis showed that age, diabetes, and D–Drate were risk factors for subsequent ATE. Increased D–Drate (by 0.001 mg/L/min; hazard ratio, 1.08; 95% CI 1.02–1.14) was an independent predictor of ATE after adjustment for potential confounders. Faster fibrin clot degradation at 3 months since VTE may increase the risk of ATE among VTE patients during follow-up.

Combined Platelet Rich Plasma and Amniotic membrane in the treatment of Perforated Corneal Ulcers

Purpose To report the outcomes of using synthetic amniotic membrane with platelet rich plasma for the primary management of corneal perforations. Setting Ophthalmology department. Faculty of Medicine, Minia University, Minia, Egypt Methods A case series of 10 patients diagnosed with corneal perforation underwent emergency surgical procedure for repair of the perforation through the implantation of synthetic amniotic membrane with platelet-rich plasma clot under it and the application of platelet-rich plasma eye drops, with a follow up period of up to 4 weeks. Results All cases demonstrated formation of adequate intraocular pressure digitally, within the first 7 days, and all cases showed complete sealing of the corneal perforation within the 4 weeks follow up period, mild symptoms were reported only in the 1st postoperative week like foreign body sensation and lacrimation. 3 of the treated patients underwent penetrating keratoplasty after 6 months with satisfactory visual outcomes. Conclusion The combination of amniotic membrane implant and platelet rich plasma in both the clot and eye drop forms is an effective and easy accessible method for the primary management of corneal perforations

Certain Associations Between Iron Biomarkers and Total and γ' Fibrinogen and Plasma Clot Properties Are Mediated by Fibrinogen Genotypes

Introduction: Evidence for the relationship between body iron and cardiovascular disease (CVD) is inconsistent and mechanisms involved remain poorly understood. Therefore, we first investigated whether there are linear or non-linear relationships between iron status and total and γ' fibrinogen as well as plasma fibrin clot properties and, second, determined whether there are interactions with iron biomarkers and fibrinogen and FXIII single nucleotide polymorphisms (SNPs) in relation to fibrinogen concentration and functionality.Methods: In this cross-sectional analysis of 2,010 apparently healthy Black South Africans we quantified total and γ' fibrinogen, serum iron, ferritin and transferrin using standardized methods and calculated transferrin saturation (TS). Clot architecture and lysis were explored with a global analytical turbidity assay. The SNPs were determined through an Illumina BeadXpress® platform.Results: Total, but not %γ', fibrinogen negatively correlated with serum iron concentrations, although both decreased over iron tertiles. %γ' fibrinogen correlated negatively with transferrin and decreased over the transferrin tertiles. A weak negative association between total fibrinogen and TS was detected with fibrinogen decreasing over the TS tertiles and categories based on TS. Lag time correlated positively with transferrin and increased over transferrin tertiles, when adjusting for fibrinogen. Before adjusting for fibrinogen, lag time was shorter in those with adequate iron status based on TS than other iron subcategories. Clot lysis time (CLT) negatively correlated with ferritin and was longer in the first than in the third ferritin tertile. Among iron status categories based on ferritin, only CLT differed and was longer in those with adequate iron than with iron-overload. CLT negatively correlated with TS, albeit weakly, shortened over the TS tertiles and was shorter in those with adequate iron based on TS categories. Interactions were observed between FGB SNPs and some of the markers of iron status investigated, in relation to the clot properties with the most prominent associations detected in homozygous carriers of the variant alleles for whom increased iron status was more beneficial than for those harboring the wild-type alleles. Iron modulated the influence of the SNPs so that for the majority iron was beneficial in respect of clot properties, but even more so for a minority group harboring specific variant alleles.Conclusion: This is the first large-scale epidemiological study to relate fibrinogen concentration and functionality to markers of iron status and to take genetic factors into consideration. We have detected a relationship between iron biomarkers and fibrinogen as well as clot characteristics that are influenced by the genetic make-up of an individual.

Microscopic Investigation of Compatibility of Samples Containing Multipotent Mesenchimal Stromal Cells of Additive Tissue in Experimental Conditions

The purpose of the study was to investigate the biocompatibility of samples containing multipotent mesenchymal stromal cells of adipose tissue to replace bone defects. Material and methods. The study was conducted at Bukovina State Medical University, Chernivtsi, Ukraine. Adipose tissue samples were obtained from the neck of 60 experimental animals (white Wistar rats). We selected 4 samples for the toxicological experiment, which allowed to establish the direct influence of factors in the contact of implantation material at the cellular level. Sample № 1 - Multipotent mesenchymal stromal cells of adipose tissue, which underwent osteogenic differentiation; № 2 - Multipotent mesenchymal stromal cells of adipose tissue with osteogenic differentiation with the addition of platelet-enriched blood plasma; № 3 - “Kolapan” with applied tissue culture of Multipotent mesenchymal stromal cells of adipose tissue cells, which underwent osteogenic differentiation; № 4 - "Kolapan" + Multipotent mesenchymal stromal cells of adipose tissue + platelet-enriched plasma. Multipotent mesenchymal stromal cells of adipose tissue were obtained by grinding adipose tissue of rats in 0.1% collagenase 1A [14]. The study of biocompatibility by cell culture in vitro was performed in accordance with the Working Instruction № 04/2013-VL. The cultures were investigated by the explantation method in a plasma clot in Karelian vials. In order to standardize the nature of growth, their zones were classified into compact, reticular and migrating cells of growing fibroblastic tissues. To assess the probability of the obtained results of the study we used a variation-statistical method of analysis using Microsoft Excel. Statistical calculation of the results of clinical and laboratory studies was carried out according to conventional methods. Results and discussion. Microscopic examination of the surface of samples with culture of fibroblasts showed their satisfactory adhesion on the tooth surface after 5 days of cultivation. In the study of sample № 1 (Multipotent mesenchymal stromal cells of adipose tissue, with osteogenic differentiation), it was noted that the structure of the cells acquired a rounded and oval shape, which indicated their destruction and damage. On the 5th day of observation, cells with numerical intussusception and processes were observed during visual examination of sample № 3 (“Kolapan”, with applied culture of Multipotent mesenchymal stromal cells of adipose tissue). In the study of samples № 4 (Multipotent mesenchymal stromal cells of adipose tissue + platelet-enriched plasma + "Kolapan") on the 5th day of research, signs of growth were manifested by migration of fibroblastic elements that had a spindle-shaped and polygonal shape, with the formation of the primary zone due to strands. On the 7th day of cultivation in experimental samples № 2, № 3, № 4 there was the formation of three growth zones: compact - from cells of polygonal and spindle-shaped form; reticulate - from strands and bundles of cells that were located reticulate and areas of single migrating elements of spindle-shaped. External characteristics and cell growth surface did not differ from control samples. On the 10th day of cultivation in the experimental samples, as well as in the control, the areas of compact and reticular growth zone and the zone of migrating fibroblasts were increased. At the same time, tissue-like growth of cells was observed. Visualization of compact and stack-like zones of the studied experimental samples revealed signs of the beginning of degenerative changes, which was characterized in the form of rounding of the shape and vacuolation of cells. This trend was most pronounced in samples № 2 and № 4. Conclusion. Thus, tissue equivalents of bone tissue based on Multipotent mesenchymal stromal cells of adipose tissue can be candidates for use in regenerative medicine, and studies of their application in experimental animals will provide an opportunity to expand the understanding of the characteristics of Multipotent mesenchymal stromal cells of adipose tissue in order to optimize their further clinical application and implement new approaches in different areas of dentistry

Accelerated Spatial Fibrin Growth and Impaired Contraction of Blood Clots in Patients with Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an autoimmune disease associated with thrombotic complications. To elucidate pathogenic mechanisms, hemostatic disorders in RA were correlated with other laboratory and clinical manifestations. Hemostasis was assessed using relatively new complementary tests, the spatial growth of a plasma clot (Thrombodynamics assay), and contraction of whole blood clots. Platelet functionality was assessed with flow cytometry that quantified the expression of P-selectin and the fibrinogen-binding capacity of platelets before and after activation with a thrombin receptor-activating peptide. Parameters of fibrin clot growth and the kinetics of contraction of blood clots were significantly altered in patients with RA compared to the control group. In Thrombodynamics measurements, an increase in the clot growth rate, size, and optical density of plasma clots altogether indicated chronic hypercoagulability. The rate and extent of blood clot contraction in patients with RA was significantly reduced and associated with platelet dysfunction revealed by an impaired response to activation. Changes in the parameters of clot growth and contraction correlated with the laboratory signs of systemic inflammation, including hyperfibrinogenemia. These results confirm the pathogenic role of hemostatic disorders in RA and support the validity of fibrin clot growth and the blood clot contraction assay as indicators of a (pro)thrombotic state.

The association of alcohol with circulating total fibrinogen and plasma clot density is mediated by fibrinogen and FXIII genotypes

Background Alcohol consumption is associated with haemostasis and so may influence cardiovascular conditions. It is unknown whether the association of alcohol with total and γ’ fibrinogen concentrations, as well as clot structure, are modulated by fibrinogen and factor (F) XIII single nucleotide polymorphisms (SNPs). Methods Total fibrinogen, γ’ fibrinogen and clot properties of 2010 healthy Africans residing in South Africa were measured in relation to alcohol intake as well as its markers – gamma-glutamyltransferase (GGT), percentage carbohydrate deficient transferrin (%CDT), aspartate aminotransferase (AST), and alanine aminotransferase (ALT). Fourteen fibrinogen and two SNPs in the FXIII gene were genotyped to determine their influence. Results Alcohol intake and its markers correlated negatively with fibrinogen and clot lysis time (CLT) as well as with most of the clot properties. Percentage γ’ fibrinogen correlated positively with AST and negatively with alcohol intake. We then stratified for alcohol intake and found inverse associations between γ’ fibrinogen and both %CDT and GGT–CDT in consumers, but the positive association with AST remained only in abstainers. Alcohol intake and its markers modulated the influence of fibrinogen SNPs on total fibrinogen concentrations and the fibrinogen SNPs as well as an FXIII SNP on clot density (all p < 0.004). Conclusion/s We show for the first time that some individuals harbour certain genotypes that, in combination with alcohol consumption, might predispose or protect them from haemostatic factors that might lead to the development of cardiovascular disease. Studies are needed to clarify the mechanisms related to the interplay between alcohol and the gene variants observed here.

Tabernaemontana divaricata Stem and Latex Proteases as Haemostatic Agent with Temporally Spaced Intense Fibrinogenolytic and Mild Fibrinolytic Activity

Background: Proteases play a crucial role in the pharmacological properties of latex producing plants. Some of them exhibited intervention with fibrinogenolysis and/or fibrinolysis, two crucial wound healing events. Objective: To evaluate wound healing potential of crude and partially purified enzyme from Tabernaemontana divaricata (stem and latex). Materials and Methods: Proteolytic activity, clot inducing/dissolving potential, fibrinogen polymerization, recalcification time, blood clot lysis and Tricine-SDS PAGE for enzyme treated fibrinogen and human plasma clot were performed. Results: Latex PPE exhibited significant proteolytic activity (115.8 ± 0.3 U/ml) compared to that of the stem (28.78 ± 0.2 U/ml). Enzyme preparations exhibited temporally spaced clot inducing and subsequent dissolving properties favoring hemostatic effect, procoagulant effect being dominant and the first event. Significant reduction in fibrinogen absorbance at 540 nm with time, recalcification time and human fibrinogenolytic product analysis on Tricine PAGE substantiated procoagulant effect. Disappearance of Aα and Bβ fibrinopeptides by both stem and latex PPEs in the PAGE was observed. γ subunits were completely hydrolysed by latex PPE, however, it showed comparative resistance to stem PPE. Reduction in blood clot weight and fibrin subunit intensity supported thrombolytic property. Conclusion: The study provides evidence of the procoagulant and thrombolytic activity associated with T. divaricata proteases.

Association of ABO Blood Group with Bleeding Severity in Patients with Bleeding of Unknown Cause

Introduction: Antigens of the ABO blood group system have an impact on the hemostatic balance. The association of blood group non-O and thrombosis risk is well known. In patients with different bleeding manifestations, an overrepresentation of blood group O has been previously reported (Dentali et al, Semin.Thromb. Hemost, 2013). Nevertheless, the independent effect of the ABO blood group on bleeding severity, when considering VWF as a major contributing factor, has not yet been thoroughly investigated. Patients with bleeding of unknown cause (BUC) have a similar bleeding phenotype as patients with a diagnosis of an established bleeding disorder, but the causes underlying their bleeding tendency are currently unclear and might be multifactorial (Gebhart et al, Haemophilia, 2018). Thus, we investigated the prevalence of blood group O and its role as an independent risk factor for increased bleeding severity in a thoroughly characterized cohort of patients with BUC. Methods: For this analysis, we selected all patients with normal results in the assessments of plasmatic coagulation and platelet function consecutively recruited between October 2009 and April 2019 within the Vienna bleeding biobank study (Figure 1; Gebhart et al, Haemophilia, 2018). After informed consent, all patients underwent a structured interview on their previous medical and bleeding history including the assessment of the bleeding severity with the Vicenza bleeding assessment tool (BAT). Biomaterial was processed and stored according to standard operating procedures at the Biobank facility (http://www.biobank.at/). A thorough hemostatic laboratory assessment and measurements of thrombin generation, plasma clot properties, and rotational thromboelastometry (ROTEM), as well as platelet function tests (PFA-100, light transmission aggregometry) were performed. Data on the blood group distribution of 23,145 healthy first-time blood donors were provided by the Austrian Red Cross for comparison. Results: We observed an overrepresentation of blood group O in 199 out of 422 BUC patients (47.2%) compared to 8709 out of 23,145 healthy blood donors (37.6%), odds ratio for blood group O 1.48; 95% CI=1.22-1.79, p&lt;0.001 (Table 1). Blood group O in comparison to non-blood group O was independently associated with an increased bleeding severity (least square mean [95% CI]: 6.2 [5.8-6.6] vs. 5.3 [4.9-5.7], p=0.006) and a higher number of bleeding symptoms (least square (LS) mean [95% CI] 3.5 [3.2-3.7] vs. 3.0 [2.8-3.2], p=0.016), after adjustment for sex, VWF:Ag, VWF:RCo and FVIII activity (Table 2). The prevalence of oral mucosal bleeding was significantly higher in blood group O than in patients with a non-O blood group (26.1% vs. 14.3%), even after adjustment for sex, VWF and FVIII, and multiple testing (p=0.013). When analyzing the influence of blood group O on tests of global hemostatic capacity, results indicated increased clot firmness and reduced lysis in blood group O patients. In ROTEM, the maximum clot firmness was higher (LS mean [95% CI]: 57.4 [56.5-58.3] vs. 55.8 [55.0-56.6] mm, p&lt;0.05) and the maximal lysis lower (LS mean [95% CI]: 13.3 [12.5-14.1] vs. 15.1 [14.4-15.9] %, p&lt;0.05) in patients with blood group O compared to non-O patients, after adjustment for sex, VWF and FVIII, and correction for multiple testing. Also in the analysis of plasma clot properties, the maximum clot absorbance was increased in patients with blood group O after adjustment for sex, VWF and FVIII (LS mean [95% CI]: 0.77 [0.74-0.79] vs 0.71 [0.69-0.74] OD, p&lt;0.05), whereas there was no difference in plasma clot lysis. There was no difference in thrombin generation between BUC patients with blood group O and non-O. We could not identify any differences in platelet function, as assessed by the platelet function analyser-100 and light transmission aggregometry between patients with blood group O in comparison to non-O patients after adjustment for sex, VWF and FVIII, and correction for multiple testing. Conclusion : Blood group O is a risk factor for a more severe bleeding phenotype, especially oral mucosal bleeding, independent of VWF and FVIII levels in patients with BUC. Alterations in global hemostatic capacity in BUC patients with blood group O were identified, whereas platelet function was not different. Our data are important for a better understanding of underlying mechanisms of bleeding in BUC patients, which are most probably multifactorial. Disclosures Jilma: True North Therapeutics: Consultancy, Other: reimbursement for travel costs for scientific presentations; Bioverativ: Consultancy, Other: reimbursement for travel costs for scientific presentations.