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Glanzmann thrombasthenia (GT) is a rare autosomal recessive disorder of fibrinogen-mediated platelet aggregation due to a quantitative or qualitative deficit of the αIIbβ3 integrin at the platelet surface membrane resulting from mutation(s) in ITGA2B and/or ITGB3. Patients tend to present in early childhood with easy bruising and mucocutaneous bleeding. The diagnostic process requires consideration of more common disorders of haemostasis and coagulation prior to confirming the disorder with platelet light transmission aggregation, flow cytometry of CD41 and CD61 expression, and/or exon sequencing of ITGA2B and ITGB3. Antifibrinolytic therapy, recombinant activated factor VII, and platelet transfusions are the mainstay of therapy, although the latter may trigger formation of anti-platelet antibodies in GT patients and inadvertent platelet-refractory disease. The management of these patients therefore remains complex, particularly in the context of trauma, labour and delivery, and perioperative care. Bone marrow transplantation remains the sole curative option, although the venue of gene therapy is being increasingly explored as a future alternative for definitive treatment of GT.

Background The causative variant remains unidentified in 2%-5% of haemophilia A (HA) patients despite an exhaustive sequencing of the full F8 coding sequence, splice consensus sequences, 5'/3' untranslated regions and copy number variant (CNV) analysis. Next-generation sequencing (NGS) has provided significant improvements for a complete F8 analysis. Aim The aim of this study was to identify and characterize pathogenic non-coding variants in F8 of 15 French and Canadian HA patients genetically unresolved, through the use of NGS, mRNA sequencing and functional confirmation of aberrant splicing. Methods We sequenced the entire F8 gene using an NGS capture method. We analysed F8 mRNA in order to detect aberrant transcripts. The pathogenic effect of candidate intronic variants was further confirmed using a minigene assay. Results After bioinformatic analysis, 11 deep intronic variants were identified in 13 patients (8 new variants and 3 previously reported). Three variants were confirmed to be likely pathogenic with the presence of an aberrant transcript during mRNA analysis and minigene assay. We also found a small intronic deletion in 6 patients, recently described as causing mild HA. Conclusion With this comprehensive work combining NGS and functional assays, we report new deep intronic variants that cause HA through splicing alteration mechanism. Functional analyses are critical to confirm the pathogenic effect of these variants and will be invaluable in the future to study the large number of variants of uncertain significance that may affect splicing that will be found in the human genome.

International audience; Background: The systemic capillary leak syndrome (SCLS), also known as Clarkson disease, is a very rare condition characterized by recurrent life-threatening episodes of vascular hyperpermeability in the presence of a monoclonal gammopathy. Extended intravenous immunoglobulin (IVIG) treatment is associated with fewer recurrences and improved survival, but the optimal treatment dosage and duration remain unknown. Objective: We aim to evaluate the safety of IVIG tapering and withdrawal in patients with SCLS. Methods: We conducted a retrospective multicenter study including all adult patients with monoclonal gammopathy–associated SCLS from the EurêClark registry who received at least 1 course of IVIG. The primary end point was overall survival according to IVIG withdrawal. Results: Fifty-nine patients of mean ± SD age 51 ± 13 years were included. Overall cumulative probabilities of 2-, 5-, 10- and 15-year survival were 100%, 85%, 72%, 44%, respectively. The IVIG was withdrawn at least once in 18 patients (31%; W+ group) and never in 41 patients (69%; W– group). Cumulative probabilities of 10-year survival in W+ versus W– groups were 50% and 83% (log rank test, P = .02), respectively. Relapse rate and the median number of relapses in the W+ versus the W– groups were 72% versus 58% (P = 0.3) and 2.5 (0.3–4) versus 1 (0–2) (P = .03), respectively. The IVIG tapering was not statistically associated with increased person-year incidence of attacks using a mixed linear model. Conclusions: The IVIG withdrawal was associated with increased mortality and higher rate of recurrence in SCLS patients. The IVIG tapering might be cautiously considered in stable SCLS patients.

Background Acquired haemophilia A (AHA) is a potentially life-threatening bleeding disorder caused by factor VIII (FVIII) autoantibodies, involving various immunoglobulin (Ig) isotypes and IgG subclasses. Objectives We analyzed the profile of Ig against FVIII in patients with AHA to identify Ig patterns predictive of bleeding phenotype and outcomes. Patients/methods Ig detection and titration were determined by enzyme-linked immunosorbent assay (ELISA) at disease presentation in a cohort of 66 subjects from the Quebec Reference Centre for Inhibitors registry. Results Most of plasma samples analyzed (97%) contained multiple anti-FVIII Ig isotypes and IgG subclasses, IgG(1,2,3,4) (24.2%), [IgG(1,2,3,4),IgA] (16.7%) and IgG(2.4) (13.6%) being the most prevalent combinations of Ig detected. AHA patients who presented with IgA antibodies were more likely to have an associated auto-immune disease (p=0.049). The presence of IgG4-was associated with bleeding symptoms at presentation (p=0.002). IgG1-positive patients were more likely to require transfusions with red packed cell (p=0.014) whereas IgM detection was associated with a higher probability of death linked to AHA (p=0.011). Conclusion The Ig pattern of AHA patients at diagnosis is widely heterogeneous and is at least partially associated with some underlying conditions. Our data supports the differential predictive significance for IgG1, IgG4 and IgM on bleeding severity and suggests that the early determination of Ig profile may help to identify AHA patients at higher risk of poorer outcomes.

Acquired haemophilia A (AHA) is a rare autoimmune bleeding disorder caused by neutralizing antibodies against factor VIII (FVIII). Despite significant initial morbidity and mortality, most patients achieve remission with immunosuppressive therapy.Long-term follow-up data from the Quebec Reference Centre for Inhibitors (QRCI) were analysed to identify factors predictive of AHA relapse and the influence of relapse on survival.Criteria used to define AHA were levels of FVIII0.3 IU/mL and FVIII inhibitor titres ≥0.6 Bethesda Units (BU). Complete remission was defined as FVIII0.5 IU/mL and/or FVIII inhibitor titres0.6 BU while not on immunosuppression.Between 2000 and 2012, 111 subjects met the inclusion criteria and were followed for a median of 25.6 months. Ninety per cent of them reached remission on immunosuppression in a median time of 45 days. Fourteen patients presented one or more relapses in a median time of 13.4 months. Most relapse episodes were successfully treated. Associated lymphoproliferative syndromes (LPS) were predictive of relapse, whereas FVIII activity and inhibitor titres at initial diagnosis or immunosuppressive regimens were not. The overall survival (OS) was the same, with or without relapse.Among the recognized potential risk factors for relapse, only LPS was statistically significant. The long-term follow-up of our patients also showed that late or multiple relapses may occur, but that relapse is not associated with a worse OS. Thus, long-term follow-up is important for optimal management of AHA.

Gaucher disease (GD) is a rare autosomal recessive multisystemic lysosomal storage disorder presenting a marked phenotypic and genotypic variability. GD is caused by a deficiency in the glucocerebrosidase enzyme. The diagnosis of GD remains challenging because of the large clinical spectrum associated with the disease. Moreover, GD biomarkers are often not sensitive enough and can be subject to polymorphic variations. The main objective of this study was to perform a metabolomic study using an ultra-performance liquid chromatography system coupled to a time-of-flight mass spectrometer to identify novel GD biomarkers. Following the analysis of plasma samples from patients with GD, and age- and gender-matched control samples, supervised statistical analyses were used to find the best molecules to differentiate the two groups. Targeted biomarkers were structurally elucidated using accurate mass measurements and tandem mass spectrometry. This metabolomic study was successful in highlighting seven biomarkers associated with GD. Fragmentation tests revealed that these latter biomarkers were lyso-Gb1 (glucosylsphingosine) and four related analogs (with the following modifications on the sphingosine moiety: -C2H4, -H2, -H2+O, and +H2O), sphingosylphosphorylcholine, and N-palmitoyl-O-phosphocholineserine. Based on the plasma biomarker distribution, we suggest the evaluation of this GD biomarker profile, which might facilitate early diagnosis, monitoring, and follow-up of patients.

Background Thrombotic thrombocytopenic purpura (TTP) is caused by the abundance of uncleaved ultralarge von Willebrand factor multimers (ULvWF) due to acquired (autoantibody-mediated) or congenital vWF protease ADAMTS13 deficiency. Current treatment recommendations include plasma exchange therapy and immunosuppression for the acquired form and (fresh) frozen plasma for congenital TTP. Case-diagnosis/treatment A previously healthy, 3-year-old boy presented with acute microangiopathic hemolytic anemia, thrombocytopenia, erythrocyturia and mild proteinuria, but normal renal function, and elevated circulating sC5b-9 levels indicating complement activation. He was diagnosed with atypical hemolytic uremic syndrome and treated with a single dose of eculizumab, followed by prompt resolution of all hematological parameters. However, undetectably low plasma ADAMTS13 activity in the pre-treatment sample, associated with inhibitory ADAMTS13 antibodies, subsequently changed the diagnosis to acquired TTP. vWF protease activity normalized within 15 months without further treatment, and the patient remained in long-term clinical and laboratory remission. Extensive laboratory workup revealed a homozygous deletion of CFHR3/1 negative for anti-CFH antibodies, but no mutations of ADAMTS13, (other) alternative pathway of complement regulators or coagulation factors. Conclusions This case, together with a previous report of a boy with congenital TTP (Pecoraro et al. Am J Kidney Dis 66:1067, 2015), strengthens evolving in-vitro and ex-vivo evidence that ULvWF interferes with complement regulation and contributes to the TTP phenotype. Comprehensive, prospective complement studies in patients with TTP may lead to a better pathophysiological understanding and novel treatment approaches for acquired or congenital forms.

Acute promyelocytic leukemia (APL) is a medical emergency because of associated lethal early bleeding, a condition preventable by prompt diagnosis and therapeutic intervention. The mechanisms underlying the hemostatic anomalies of APL are not completely elucidated. RNA-sequencing-based characterization of APL (n = 30) was performed and compared to that of other acute myeloid leukemia (n = 400) samples and normal promyelocytes. Perturbations in the transcriptome of coagulation and fibrinolysis-related genes in APL extend beyond known culprits and now include Thrombin, Factor X and Urokinase Receptor. Most intriguingly, the Podoplanin (PDPN) gene, involved in platelet aggregation, is aberrantly expressed in APL promyelocytes and is the most distinctive transcript for this disease. Using an antibody panel optimized for AML diagnosis by flow cytometry, we also found that PDPN was the most specific surface marker for APL, and that all-trans retinoic acid therapy rapidly decreases its expression. Functional studies showed that engineered overexpression of this gene in human leukemic cells causes aberrant platelet binding, activation and aggregation. PDPN-expressing primary APL cells, but not PDPN-negative primary leukemias, specifically induce platelet binding, activation and aggregation. Finally, PDPN expression on leukemia cells in a xenograft model was associated with thrombocytopenia and prolonged bleeding time in vivo. Together our results suggest that PDPN may contribute to the hemostatic perturbations found in APL.

Background: Inhibitor development in previously untreated patients (PUPs) with severe haemophilia A is a multifactorial event. It is unknown whether paediatric vaccinations given in close proximity to factor VIII (FVIII) are associated with inhibitor development. Objective: To assess whether paediatric vaccinations in close proximity to FVIII within the first 75 exposure days (EDs) are associated with inhibitor development in PUPs with severe haemophilia A. Methods: We included 375 PUPs with severe haemophilia A (

Thrombotic microangiopathies (TMA) constitute a group of life-threatening diseases of different aetiologies characterized by similar symptoms. The compilation of comprehensive data related to the initial clinical presentation of TMA is challenging due to their rare occurrence. The objective of this study was to assess and determine the predictive value of the clinical presentation of patients with a suspected TMA episode, subsequently confirmed as thrombotic thrombocytopenic purpura (TTP), compared with non-TTP TMA by taking advantage of the centralized ADAMTS-13 testing in Quebec. All ADAMTS-13 activity and antibody titration were performed at CHU Saint-Justine (CHUSJ). Measurements and patient demographics (from April 2012 to December 2019) were extracted from the Laboratory Information System of the CHUSJ. Patients with presumed TMA were classified into TTP when ADAMTS-13 activity was ≤10%, or suspicion of TMA other than TTP (non-TTP TMA) when ADAMTS-13 activity was >10%. Clinical presentation was obtained through a survey form received with each plasma sample and containing information related to prior episodes of TMA, underlying conditions (pregnancy, cancer, infection, transplant, medication, other), clinical symptoms (fever, neurological signs, abdominal signs), and biological parameters (hemolytic anemia, thrombocytopenia). Statistical analyses were performed with IBM SPSS 26.0. The study was approved by the Research Ethics Committee of CHUSJ. A total of 2081 requests for ADAMTS13 testing were received during the study period, in 846 different individuals with suspected TMA: 147 patients (17%) had a confirmed TTP and 699 had a suspected non-TTP TMA. Clinical and biological characteristics associated with TMA suspicion were available for 105 TTP and 470 non-TTP TMA patients (68% of subjects). More than half of patients with TTP (55%; 48/87) had neurological signs at presentation compared to one third of patients (33%; 124/375) with non-TTP TMA (p=0.0001). There were no significant differences regarding fever and abdominal signs between the 2 groups (p=0.383 and p=0.355 respectively). Anemia and thrombocytopenia were reported in 92% (80/87) and 93% (86/92) of TTP patients compared to 74% (291/396) and 83% (352/426) of non-TTP TMA patients (p=0.0002 and p=0.009, respectively). Underlying conditions were reported in 62% (287/460) of non TTP-TMA patients compared to 35% (34/97) of TTP patients (p When addressing the odds of TPP according to the clinical presentation, patients with neurological signs were at higher risk to be diagnosed with TTP compared to those who did not have neurological signs (odds ratio, 2.52; IC95%, 1.51 to 4.20; p In conclusion, the centralization of ADAMTS-13 activity testing in one reference center has enabled to determine the predictive value of clinical characteristics associated with TPP in comparison to other types of TMA for the entire province of Quebec, Canada. This study provides useful insight for caregivers and paves the way to the establishment of a provincial registry of TMA patients. Figure 1 Figure 1. Disclosures Lapeyraque: Alexion Pharmaceuticals Inc: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Rivard: Bayer Inc: Membership on an entity's Board of Directors or advisory committees, Research Funding; Octapharma Inc: Membership on an entity's Board of Directors or advisory committees; Pfizer Inc: Membership on an entity's Board of Directors or advisory committees, Research Funding; CSL Behring Inc.: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novo Nordisk Inc: Membership on an entity's Board of Directors or advisory committees. Bonnefoy: Alexion Pharmaceuticals Inc: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi Genzyme Inc: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; CSL Behring Inc: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees.

Primary and secondary thrombotic microangiopathies (TMA) constitute a group of life-threatening diseases of different aetiologies characterized by similar symptoms. The comprehensive compilation of data related to TMA is challenging due to their rare occurrence. The objective of this study was to provide an overview of the incidence of thrombotic thrombocytopenia (TTP) and non-TTP TMAs in the Province of Quebec (PQ) (8.485 Million inhabitants in 2019) by taking advantage of the centralized ADAMTS-13 activity and antibody testing for PQ since 2013 at the CHU Sainte-Justine (CHUSJ) All ADAMTS-13 activity and antibody titration were performed locally at CHUSJ. ADAMTS-13 results and patient demographic characteristics from April 2012 to December 2019 were extracted from the Laboratory Information System of CHUSJ and used in an anonymized database. Information on previous TMA episodes was obtained from a standardized clinical assessment form accompanying each plasma sample. Statistical analyses were performed with IBM SPSS version 26.0. The annual incidence rates were calculated based on the number of patients with a first-time recorded diagnosis of TMA using the Quebec mid-year (yr) estimated population of the years at stake. Patients with suspected TMA were further divided into two categories: individuals with TTP, defined by either an ADAMTS-13 activity ≤10% or a positive anti-ADAMTS-13 antibody titration, and patients with a suspected TMA other than TTP (non-TTP TMA) with a result of ADAMTS-13 activity >10%. The study was approved by the Research Ethics Committee of CHUSJ. A progressive increase in the annual requests for ADAMTS13 activity was observed over the study period. The number of new patients increased from 2012 to 2016 but plateaued after 2016 at an average number of 170 new patients per year. The number of confirmed TTP cases in Quebec was higher from 2014 to 2018 compared to in 2012, 2013 and 2019 (Figure 1). A total of 2081 requests for ADAMTS13 activity testing were received during the study period, representing 846 subjects with a suspected TMA. 147 subjects (17%) had a confirmed TTP and 699 (83%) had a suspected non-TTP TMA. TMAs were suspected more often in females (59%), both in confirmed TTP (62%) and non-TTP TMA (58%). The mean annual incidence rate (MAIR) of TTP was 1.91 case/million/yr (95%CI: 1.46-2.35). This was higher in females (2.36 cases/million/yr; 95%CI: 1.34-3.37) compared to males (1.42 case/million/yr; 95%CI: 0.57-1.44; p=0.001). The MAIR of non-TTP TMA was 9.97 cases/million/yr (95%CI:5.85-14.09), 11.52 for females (95%CI:6.71-16.33) versus 8.41 for males (95% CI: 4.81-12.02; p=0.001). In non-TPP TMA, the MAIR for males ranged from 3.9 to 7.2 cases per million prior to 60 year of age and increased after up to 24.5 at ages 80-89. For females, a first peak MAIR above 10 cases per million was observed during their thirties and a second peak was observed during their seventies (Figure 2). In TPP, peaks incidences in females were observed from ages 20 to 49. It dipped from ages 50 to 69 and then increased again. In males, a highest MAIR was observed between ages 40 to 79. In conclusion, the provincial centralization of ADAMTS-13 testing has enabled us to depict comprehensive picture of TTP and other suspected non-TPP TMA, thereby providing valuable information for caregivers and health authorities into these rare diseases. Sex and age related incidences observed in this study are comparable to those obtained through other registries and aggregated studies. Further analyses on clinical presentation of TMAs and patient follow up are now possible using the identification of this large cohort. Figure 1 Figure 1. Disclosures Lapeyraque: Alexion Pharmaceuticals Inc: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Rivard: Bayer Inc: Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer Inc: Membership on an entity's Board of Directors or advisory committees, Research Funding; Octapharma Inc: Membership on an entity's Board of Directors or advisory committees; Novo Nordisk Inc: Membership on an entity's Board of Directors or advisory committees; CSL Behring Inc.: Membership on an entity's Board of Directors or advisory committees, Research Funding. Bonnefoy: Sanofi Genzyme Inc: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; CSL Behring Inc: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Alexion Pharmaceuticals Inc: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.

Inherited platelet function disorders (IPFD) have been assessed for more than 50 years by aggregation- and secretion-based tests. Several decision trees are available intending to standardize the investigation of IPFD. A large variability of approaches is still in use among the laboratories across the world. In spite of costly and lengthy laboratory evaluation, the results have been found inconclusive or negative in a significant part of patients having bleeding manifestations. Molecular investigation of newly identified IPFD has recently contributed to a better understanding of the complexity of platelet function. Once considered "classic" IPFDs, Glanzmann thrombasthenia and Bernard-Soulier syndrome have each had their pathophysiology reassessed and their diagnosis made more precise and informative. Megakaryopoiesis, platelet formation, and function have been found tightly interlinked, with several genes being involved in both inherited thrombocytopenias and impaired platelet function. Moreover, genetic approaches have moved from being used as confirmatory diagnostic tests to being tools for identification of genetic variants associated with bleeding disorders, even in the absence of a clear phenotype in functional testing. In this study, we aim to address some limits of the conventional tests used for the diagnosis of IPFD, and to highlight the potential contribution of recent molecular tools and opportunities to rethink the way we should approach the investigation of IPFD.

Objective We recently investigated the pathways of immunoreactive bradykinin (iBK) formation in fresh blood of normal volunteers and of patients with hereditary angioedema due to C1-esterase inhibitor deficiency (HAE-1/-2). Herein, we adapted the techniques to small volumes (200 μl) of previously frozen citrated plasma and further analyzed the mechanisms of iBK formation with additional biotechnological inhibitors. Results Measurable iBK formation was observed under stimulation with tissue kallikrein (KLK-1, 10 nM), the particulate material Kontact-APTT (concentration reduced to 2% v/v) or recombinant tissue plasminogen activator (tPA, 169 nM), with little background in unstimulated plasma incubated for up to 2 h. Plasma samples from HAE-1/-2 patients responded earlier to tPA than those from controls, as previously reported with whole blood. Lanadelumab inhibited iBK formation induced by Kontact-APTT and tPA. A highly specific plasmin inhibitor, DX-1000, abolished tPA-induced iBK formation in plasma but had no effect against Kontact-APTT, confirming the role of fibrinolysis in tPA-induced kinin formation. The anti-lanadelumab neutralizing antibody M293-D02 reversed the inhibitory effects of lanadelumab. Frozen plasma is a suitable material for measuring iBK formation kinetics, with possible applications such as investigating the effect of rare disease states on the kallikrein–kinin system and monitoring the effect of HAE prophylactic treatments. Electronic supplementary material The online version of this article (10.1186/s13104-019-4335-8) contains supplementary material, which is available to authorized users.

Introduction Standard prophylaxis has been shown to be an effective treatment for severe haemophilia A. According to pharmacokinetic principles, daily factor infusions of smaller doses can maintain similar trough factor VIII (FVIII) levels, and perhaps the same protection as standard prophylaxis. Aim This multicentre study examined the feasibility of daily prophylaxis for youth and young adults with severe haemophilia A in Montreal and Toronto. Methods Bleeding rates, joint status, quality of life and physical activity were monitored for 14 patients during this study. At baseline, subjects continued their regular treatment regimen and switched to daily prophylaxis after 4 months; nine had begun daily prophylaxis before enrolment. Additional visits occurred at 8 and 12 months which included a physical examination, inhibitor testing, HJHS and FISH assessments, the CHO-KLAT/Haemo-QoL-A and PDPAR. Treatment satisfaction was assessed using the Treatment Satisfaction Questionnaire for Medication ver.II and perceived difficulty questions at the end of study. Results and conclusions There were no significant changes in quality of life except for concerns with the demanding daily infusion schedule. The number of bleeds did not statistically differ from the initial 4 months of the study to the last 8 months. Monthly bleeding rates from the year prior to the study and during the intervention phase were not statistically different. It was also found that daily prophylaxis used 24% less FVIII compared to standard prophylaxis. Taking all of this into account, we have found that providing daily prophylaxis is feasible and that it is feasible to prospectively study daily prophylaxis in youth and young adults.

Aims The isolated human umbilical vein is a robust contractile bioassay for ligands of the bradykinin (BK) B 2 receptor (B 2 R), also extendable to B 1 receptor (B 1 R) pharmacology. We hypothesized that, as a freshly isolated vessel, it also contains traces of plasma proteins that may confer responses to exogenous proteases via the formation of kinins. Main methods Rings of human umbilical veins were mounted in organ baths containing Krebs buffer maintained at 37 °C and purified proteases were introduced in the bathing fluid along with additional drugs/proteins that permit mechanistic analysis of effects. Key findings The previously described contractile response to human recombinant tissue kallikrein (KLK-1, 1–10 nM) is not influenced by metabolic inhibitors, suggesting its dependence on a preexisting reservoir of low molecular weight-kininogen (LK). Active plasma kallikrein (apK, ≤ 5 nM) was inactive in fresh tissues, unless high molecular weight-kininogen (HK, 39–197 nM) replenishment was applied. The effects of KLK-1 and HK + apK are abolished by pretreating tissues with icatibant, but not with tranexamic acid. C1-esterase inhibitor inhibited only HK + apK. Purified plasmin and neutrophil proteinase-3 produced small contractions in the presence of HK only, and tissue plasminogen activator, none. B 1 R stimulation was pharmacologically evidenced in response to KLK-1 if LK was supplied. Significance The pharmacology of KLK-1 and HK + apK in the human isolated umbilical vein is essentially based on the activity of locally generated kinins and this assay models the inhibitory action of some therapeutic agents active in angioedema states. Proteases that indirectly generate kinins have little activity in the system.

Background Acquired factor VII (FVII) deficiency with inhibitor increases the risk of hemorrhage during pregnancy. However, there are no published reports guiding its management in the peripartum period. Case A 24-year-old woman with inhibitory antibodies to FVII delivered at 34 weeks of gestation. The patient was administered recombinant factor VIIa (rFVIIa) and tranexamic acid. There were no bleeding-related complications; however, the FVII level was supratherapeutic. The patient returned during a second pregnancy. A reduced dose of rFVIIa was administered. The delivery was complicated by postpartum hemorrhage, which resolved with the addition of uterotonic agents. Conclusion Recombinant FVIIa and tranexamic acid offer an effective peripartum treatment in women with inhibitory antibody to FVII. Further research should delineate the optimal time of administration.

Acquired hemophilia A (AHA) is a rare acquired bleeding disorder caused by autoantibodies against autologous factor VIII (FVIII). It is a disease that most commonly affects the elderly, but it has been described in children and during the post-partum period. It is idiopathic in 50% of cases and is associated with autoimmune disease, malignancy, pregnancy, infection or certain medications in the other 50%. The diagnosis should be suspected in patients with an isolated prolonged aPPT without previous personal or familial bleeding history. Treating the bleeding and eradication of the inhibitor is the mainstay of treatment. The first line of treatment for acute bleeding is the use of bypassing agents. The most commonly used method for eradicating the inhibitor is immunosuppression, namely corticosteroids alone or in combination with cyclophosphamide. This review summarises current knowledge and reviews management options and guidelines.

Background: Hereditary angioedema due to C1 inhibitor deficiency (C1-INH-HAE) is an autosomal dominant disease resulting in random and unpredictable attacks of swelling. The swelling in C1-INH-HAE is a result of impaired regulation of bradykinin production. The fact that the array of tests needed to diagnose HAE is not always available to the treating physicians is challenging for them and their patients. Methods: The data for this article were extracted from two distinct surveys. The first survey was conducted among HAE treating physicians and aimed to determine the availability and utilization of the various assays performed to help the diagnosis of C1-INH-HAE. The second survey was conducted with the various laboratories across Canada that performs the assays used in the diagnosis of HAE. The aim of this survey was to determine the availability and profile of the various assays used in the diagnosis of C1-INH-HAE in Canada, thereby ultimately bringing a rational basis for the biological testing. Results: C1-INH functional assay was widely available in Canada (93%), but was only offered by a small numbers of hospitals meaning that there could be longer delays in the analysis of these samples that may explain why the physicians expressed a lower level of confidence in this assay (59%). Antigenic C1-INH was available to the vast majority of the physicians treating C1-INH-HAE (93%) and was considered reliable by 96% of the respondents. Antigenic C4 was found available to all Canadian physicians and, although with limited specificity, was considered very reliable by all the participants. This study revealed that 81% of physicians were able to order the antigenic C1q and the confidence in this assay was moderate (70%). Concerning genetic testing, the survey revealed that most of the CHAEN members never had to or couldn’t order this test. Conclusion: This study highlights the need for improved education and knowledge exchange, about biological assays available to Canadian physicians and their performance in proper diagnosis of C1-INH-HAE to improve confidence and access to relevant tests.

Multiple pathways have been proposed to generate bradykinin (BK)-related peptides from blood. We applied various forms of activation to fresh blood obtained from 10 healthy subjects or 10 patients with hereditary angioedema (HAE, type I or II) to investigate kinin formation. An enzyme immunoassay for BK was applied to extracts of citrated blood incubated at 37°C under gentle agitation for 0-2 hrs in the presence of activators and/or inhibitory agents. Biologically active kinins in extracts were corroborated by c-Fos accumulation in HEK 293a cells that express either recombinant human B2 or B1 receptors (B2R, B1R). Biological evidence of HAE diagnostic and blood cell activation was also obtained. The angiotensin converting enzyme inhibitor enalaprilat, without any effect per se, increased immunoreactive BK (iBK) concentration under active stimulation of blood. Tissue kallikrein (KLK-1) and Kontact-APTT, a particulate material that activates the contact system, rapidly (5 min) and intensely (> 100 ng/mL) induced similar iBK generation in the blood of control or HAE subjects. Tissue plasminogen activator (tPA) slowly (≥ 1 hr) induced iBK generation in control blood, but more rapidly and intensely so in that of HAE patients. Effects of biotechnological inhibitors indicate that tPA recruits factor XIIa (FXIIa) and plasma kallikrein to generate iBK. KLK-1, independent of the contact system, is the only stimulus leading to an inconsistent B1R stimulation. Stimulating neutrophils or platelets did not generate iBK. In the HAE patients observed during remission, iBK formation capability coupled to B2R stimulation appears largely intact. However, a selective hypersensitivity to tPA in the blood of HAE patients suggests a role of plasmin-activated FXIIa in the development of attacks. Proposed pathways of kinin formation dependent on blood cell activation were not corroborated.

The primary objective was to assess the effect of ABO blood group on von Willebrand factor (VWF) rise induced by four bouts of moderate-intensity physical activity, on pharmacokinetics of a B-domain-deleted recombinant FVIII (BDD-rFVIII), and haemostatic parameters in severe haemophilia A patients with a null mutation. The secondary objective was to compare the response to exercise according to infused product type in a subgroup of patients who previously participated to the same exercise protocol, while treated with a full length recombinant FVIII (FL-rFVIII). Twenty patients had two visits (rest and exercise). Blood samples were drawn before administration of BDD-rFVIII and at 6 time points, until 24 h postinfusion. FVIII activity increased transiently by 1.1-fold, but only after the first exercise session, as compared to rest. VWF:Ag and platelet count were significantly elevated after each session. Mean FVIII half-life and thromboelastography measurements were unchanged with exercise. However, 14 participants had a slight variation of FVIII half-life with exercise compared to rest (from -3.42 h to +2.51 h). Seven patients demonstrated a longer FVIII half-life (four with O blood group), whereas the remainders had a reduced half-life (three with O blood group). FVIII half-life correlated with baseline VWF:Ag at rest (r = 0.70, P

Introduction Following a provincial tender, most subjects with haemophilia A in Quebec switched their treatment to a third-generation recombinant B-domain-deleted factor VIII (FVIII). Aim Our objective was to evaluate the incidence of inhibitor development and FVIII recovery in patients following the switch of factor replacement therapy. Methods One hundred and thirty-five subjects were enrolled and tested for FVIII activity and inhibitors every 6 months during 1 year. Subjects with mild haemophilia A or current inhibitors were excluded. Data on demographics, bleeds and FVIII usage were collected. Results A total of 125 switchers and 10 non-switchers were enrolled. Most subjects had severe haemophilia A (95.6%) and were on prophylaxis (89.6%). Mean FVIII recovery was similar at 0, 6 and 12 months postswitch. Two switchers developed de novo inhibitors in the 6 months postswitch, one of which was transient. No recurrent inhibitor was observed. A small but significant increase in FVIII usage was observed for adult switchers and the whole cohort of switchers and non-switchers. There was an increase in the annualized bleeding rate (ABR) for non-joint bleeds for the whole cohort of switchers. However, no significant differences were observed in ABR for joint bleeds. Conclusion Our surveillance study shows comparable inhibitor development to similar published studies. A significant increase in FVIII utilization was noted for the whole cohort, switchers and non-switchers. Lastly, no clinically significant changes were observed in ABR for joint bleeds, but a difference for non-joint bleed ABRs was observed in switchers.

International audience; Background: Monoclonal gammopathy-associated systemic capillary-leak syndrome, also known as Clarkson disease, is a rare condition characterized by recurrent life-threatening episodes of capillary hyperpermeability in the context of a monoclonal gammopathy. This study was conducted to better describe the clinical characteristics, natural history, and long-term outcome of monoclonal gammopathy-associated systemic capillary-leak syndrome.Methods: We conducted a cohort analysis of all patients included in the European Clarkson disease (EurêClark) registry between January 1997 and March 2016. From diagnosis to last follow-up, studied outcomes (eg, the frequency and severity of attacks, death, and evolution toward multiple myeloma) and the type of preventive treatments administered were monitored every 6 months.Results: Sixty-nine patients (M/F sex ratio 1:1; mean ± SD age at disease onset 52 ± 12 years) were included in the study. All patients had monoclonal gammopathy of immunoglobulin G type, with kappa light chains in 47 (68%). Median (interquartile range) follow-up duration was 5.1 (2.5-9.7) years. Twenty-four patients (35%) died after 3.3 (0.9-8) years. Fifty-seven (86%) patients received at least one preventive treatment, including intravenous immunoglobulins (IVIg) n = 48 (73.8%), theophylline n = 22 (33.8%), terbutaline n = 22 (33.8%), and thalidomide n = 5 (7.7%). In the 65 patients with follow-up, 5- and 10-year survival rates were 78% (n = 35) and 69% (n = 17), respectively. Multivariate analysis found preventive treatment with IVIg (hazard ratio 0.27; 95% confidence interval, 0.10-0.70; P = .007) and terbutaline (hazard ratio 0.35; 95% confidence interval, 0.13-0.96; P = .041) to be independent predictors of mortality.Conclusions: We describe the largest cohort to date of patients with well-defined monoclonal gammopathy-associated systemic capillary-leak syndrome. Preventive treatment with IVIg was the strongest factor associated with survival, suggesting the use of IVIg as the first line in prevention therapy.

Introduction Inherited defects in RUNX1 are important causes of platelet function disorders. Aim Our goals were to evaluate RUNX1-related platelet disorders among individuals evaluated for uncharacterized, inherited platelet function disorders and test a proof of concept that bleeding risks could be quantitatively estimated for typical families with an inherited platelet function disorder. Methods Index cases with an uncharacterized inherited platelet function disorder were subjected to exome sequencing with confirmation of RUNX1 mutations by Sanger sequencing. Laboratory findings were obtained from medical records and persistence of platelet non-muscle myosin heavy chain IIB (MYH10), a biomarker of RUNX1 defects, was assessed by Western blotting. Bleeding histories were assessed using standardized assessment tools. Bleeding risks were estimated as odds ratios (OR) using questionnaire data for affected individuals compared to controls. Results Among 12 index cases who had their exomes sequenced, one individual from a family with eight study participants had a c.583dup in RUNX1 that segregated with the disease and was predicted to cause a frameshift and RUNX1 haploinsufficiency. Unlike unaffected family members (n = 2), affected family members (n = 6) had increased bleeding scores and abnormal platelet aggregation and dense granule release responses to agonists but only some had thrombocytopenia and/or dense granule deficiency. This family's mutation was associated with persistence of MYH10 in platelets and increased risks (OR 11–440) for wound healing problems and mild bleeding symptoms, including bleeding interfering with lifestyle in women. Conclusion Inherited platelet dysfunction due to a RUNX1 haploinsufficiency mutation significantly increases bleeding risks.

BACKGROUND L-asparaginase is a cornerstone treatment for children with acute lymphoblastic leukemia (ALL). However, immune reaction to the drug may increase the clearance or impair the function of L-asparaginase and reduces its therapeutic efficacy. The objective of this study was to identify potential plasma proteins that could be used as proxies for L-asparaginase activity. METHODS Fibrinogen, von Willebrand factor antigen (VWF:Ag), total protein, and albumin levels as well as antithrombin (AT) and L-asparaginase activities were measured in 97 children with ALL treated for prolonged period of time with L-asparaginase. Binary logistic regression and a receiver operating characteristic (ROC) curve analysis were performed to evaluate the predictive value of plasma proteins for L-asparaginase activity. RESULTS Median E. coli L-asparaginase activity was 220 IU/L (range, 0-1308) throughout the treatment period. L-asparaginase activity was below 100 IU/L in 23% of measured samples. L-asparaginase activity was inversely associated with AT activity, fibrinogen, total protein, and albumin levels (r = -0.63, -0.62, -0.57, and -0.45, respectively; P

Summary. Background/objectives: Tailored primary prophylaxis (TPP) is a reduced-intensity treatment program for hemophiliacs with the goal of preventing arthropathy. Our primary aim was to evaluate the joint outcomes of treated subjects using magnetic resonance imaging (MRI) and physical examination as outcome measures. Methods: Ankles, elbows and knees (index joints) of 24 subjects (median [range] age at start of therapy, 1.6 [1–2.5] years) with severe hemophilia A enrolled in the Canadian Hemophilia Primary Prophylaxis Study (CHPS) were examined by MRI at a median age of 8.8 years (range 6.2–11.5 years). Subjects were treated with TPP using a recombinant factor VIII concentrate, starting once weekly and escalating in frequency and dose according to frequency of bleeding. Results: Osteochondral changes (cartilage loss/subchondral bone damage) were detected in 9% (13/140) of the index joints and 50% (12/24) of study subjects. Osteochondral changes were restricted to joints with a history of clinically reported joint bleeding. Soft tissue changes were detected in 31% (20/65) of index joints with no history of clinically reported bleeding (ankles 75% (12/16); elbows 19% (6/32); and knees 12% (2/17)). In these apparently ‘bleed free’ index joints hemosiderin deposition was detected by MRI in 26% (17/65) of joints (ankles 63% (10/16); elbows 16% (5/32), and knees 12% (2/17)). Conclusion: TPP did not completely avoid the development of MRI-detected structural joint changes in hemophilic boys in this prospective study. A longer period of follow-up is required for assessment of the longitudinal course of these early changes in hemophilic arthropathy, detected using a sensitive imaging technique (MRI).

Blood in the joint causes a number of physiological and pathological events that eventually lead to haemophilic arthropathy. Animal models show that blood in the joint induces inflammation that continues long after blood has been cleared. TNF-alpha, IL-1 beta and IL-6 are inflammatory mediators that increase following haemarthrosis in haemophilic mice. Conventional anti-inflammatory drugs have failed to demonstrate a lasting effect in preventing haemophilic arthropathy. A new TNF-alpha antagonist has shown promising results in haemophilic mice. Similarly, the use of cyclo-oxygenase-2 inhibitors may reduce angiogenesis associated with the healing process following bleeding and the associated tissue damage. Animal models are useful for studying the pathophysiology of haemarthropathy, however, when applying results from animals to humans, the differences in matrix turnover rate, thickness of cartilage and joint biomechanics must be kept in mind. In people with haemophilia, there is a variable response to haemarthrosis as demonstrated by magnetic resonance imaging (MRI). Up to 30% of subjects have normal MRI despite having three or more haemarthroses into the same joint. Once bone damage is present, little can be done to restore anatomic integrity. Several molecules, including members of the bone morphogenic protein subfamily, have been injected into bone defects in non-haemophilic subjects with some evidence of benefit. To achieve the primary goal of reducing blood in the joint and the negative sequelae, it is questionable to use ice to treat haemarthrosis. Indeed low temperature is associated with impairment of coagulation enzyme activity and platelet function.

Radiosynoviorthesis (RS) is an intra-articular injection of a radioactive colloid for the treatment of synovitis administered most often to patients with rheumatoid arthritis or haemophilia. Although highly cost-effective in comparison with surgical or arthroscopic synovectomy, the risk of cancer associated with this treatment is not well known. We evaluated the incidence of cancer in a group of patients treated with RS. A cohort of 2412 adult patients with a variety of underlying conditions (mainly rheumatoid arthritis) and treated with at least one RS between January 1976 and December 2001, was recruited from two centres in Montreal. Cancer incidence and mortality data for cohort members over that time period were obtained from regulatory agencies using linkage. Background rates for all and specific types of cancer were obtained for the provincial (Quebec) and national (Canada) population according to age, gender and calendar period categories. Category-specific rates in the cohort were compared with rates in similar categories from the general population generating standardized incidence ratios (SIR). The effects of specific isotope doses and of number of RS treatments were analysed using a Cox-regression model. No increase in the risk of cancer was observed (SIR 0.96; 95% confidence interval 0.82-1.12). There was no dose-response relationship with the amount of radioisotope administered or number of RS treatments. The study provides some indication for the safety of the procedure but homogenous diagnostic groups of younger patients (such as haemophilic patients) receiving RS will need more evaluation.

Background This study was undertaken to explore the longitudinal patterns of health-related quality of life (HRQoL) among youth and young adults with Hemophilia A (HA) over a 3-year period. This report presents the baseline characteristics of the study cohort. Methods Males, 14 to 29 years of age, with predominantly severe HA were recruited from six treatment centres in Canada. Subjects completed a comprehensive survey. HRQoL was measured using: the CHO-KLAT2.0 (youth), Haemo-QoL-A (young adults) and the SF-36v2 (all). Results 13 youth (mean age = 15.7, range = 12.9-17.9 years) and 33 young adults (mean age = 23.6; range = 18.4 -28.7 years) with moderate (7 %) and severe (93 %) HA were enrolled. All were on a prophylactic regimen with antihemophilic factor (Helixate FS®) during the study. The youth had minimal joint damage (mean HJHS = 5.2) compared to young adults (mean HJHS = 13.3). The mean HRQoL scores for youth were: 79.2 (SD = 11.9) for the CHO-KLAT, and 53.0 (5.5) and 52.3 (6.8) for the SF-36 Physical Component Summary (PCS) and Mental Component Summary (MCS) scores respectively. The mean HRQoL scores for young adults were: 85.8 (9.5) for the Haemo-Qol-A, and 50.8 (6.4) and 50.9 (8.8) for PCS and MCS respectively. PCS and MCS scores were comparable to published Canadian norms, however significant differences were found for the domains of Physical Functioning and Bodily Pain. The disease-specific HRQoL scores were weakly correlated with the PCS for youth (CHO-KLAT vs. PCS r = 0.28, p = 0.35); and moderately correlated for the MCS (r = 0.39, p = 0.19). Haemo-QoL-A scores for young adults were strongly correlated with the PCS (r = 0.53, p = 0.001); and weakly correlated with the MCS (r = 0.26, p = 0.13). Joint status as assessed by HJHS was correlated with PCS scores. A history of lifelong prophylaxis resulted in better PCS but worse MCS scores. Conclusion Despite having hemophilia, the youth in this cohort have minimal joint disease and good HRQoL. The young adults demonstrated more joint disease and slightly worse HRQoL in the domains of physical functioning and pain. The data presented here provide new information to inform the selection of Health Related Quality of Life (HRQoL) instruments for use in future clinical trials involving persons with hemophilia. Trial registration ClinicalTrials.gov : NCT01034904. Study funded by CSL Behring Canada. Electronic supplementary material The online version of this article (doi:10.1186/s12878-016-0052-x) contains supplementary material, which is available to authorized users.

Annual reporting of inhibitors to factors (FVIII) and IX (FIX) to the Canadian Haemophilia Registry has suggested a lower prevalence than that published in the literature. We performed a prospective study to determine the prevalence of patients with inhibitors directed against either FVIII or FIX. Patients with inhibitors were classified as: (i) inhibitor test positive; (ii) inhibitor test negative but on immune tolerance induction (ITI); (iii) inhibitor test negative but bypass treatment recommended; or (iv) inhibitor resolved. One year later, the cohort was re-classified. The prevalence of inhibitors on 1 May, 2007 was 3.3% for haemophilia A, 0.6% for haemophilia B and 8.9% and 2.1% for severe haemophilia A and B. One year later 17 individuals gained and 11 individuals lost inhibitor status (10 of these with ITI). This study suggests that the prevalence of inhibitors in our population is lower than that was previously published. We hypothesize that this is primarily due to the increased use of ITI, but other factors may be the unselected nature of the cohort and the restriction of the study to one date thereby conforming as close as practical to the definition of prevalence rather than incidence. The classification system used in this study was easy for clinics to apply and was important in defining the population with inhibitors.

Summary. Background: Replacement therapy for hemophilic patient treatment is costly, because of the high price of pharmacologic products, and is not affordable for the majority of patients in developing countries. Objective: To generate and evaluate low molecular weight agents that could be useful for hemophilia treatment. Methods: Potential agents were generated by synthesizing specific inhibitors [6-(Lys-Lys-Thr-[homo]Arg)amino-2-(Lys[carbobenzoxy]-Lys[carbobenzoxy]-O-benzyl)naphthalenesulfonamide] (PNASN-1)] for activated protein C (APC) and tested in plasma and fresh blood from hemophilia A patients. Results: In the activated partial thromboplastin time-based APC resistance assay, PNASN-1 partially neutralized the effect of APC. In calibrated automated thrombography, PNASN-1 neutralized the effect of APC on thrombin generation in normal and congenital factor VIII-deficient plasma (FVIII:C

Summary. Individuals with haemophilia A exhibit bleeding tendencies that are not always predicted by their factor (F)VIII level. It has been suggested that bleeding in haemophilia is due not only to defective prothrombin activation but also aberrant fibrinolysis. Thrombin activatable fibrinolysis inhibitor (TAFI) activation was measured in tissue factor (TF)-initiated blood coagulation in blood samples of 28 haemophiliacs and five controls. Reactions were quenched over time with FPRck and citrate and assayed for TAFIa and thrombin-antithrombin (TAT). The TAFIa potential (TP), TAFI activation rate and the TAFIa level at 20 min (TAFIa20 min) was extracted from the TAFI activation progress curve. In general, the time course of TAFI activation follows thrombin generation regardless of FVIII activity and as expected the rate of TAFI activation and TP decreases as FVIII decreases. The magnitude of TP was similar among the control subjects and subjects with

Laboratory evaluation of bleeding disorders has been performed with the standard clotting assays such as the PT and PTT for several decades. Our improved understanding of the process of blood coagulation has now revealed the important role played by the cellular elements such as platelets, monocytes and red blood cells. The need for a test that can assess clotting in a more 'global' manner, beyond the initiation of clot formation, has led to greater interest in assays such as thrombin generation and thromboelastography. Even though there are several publications using thromboelastography it remains a research tool as the methodology is not standardized. In an attempt to show reproducibility and consistency using thromboelastography, a group of investigators from different countries joined hands to form the TEG-ROTEM Working Group. Two studies were performed using PRP and FVIII deficient plasma and an intrinsic pathway activator. This article summarizes the results of the first international effort at standardization of thromboelastography. Both of the instruments using this technology (TEG(®) and ROTEM(®)) were used. Nine laboratories from countries around the globe participated in this effort. The results showed a significant inter-laboratory variance with CV's greater than 10%. Although these results were not satisfactory, this has been the first effort to standardize this methodology and significant work remains to be done to improve reliability and reproducibility. These studies were performed on PRP and the results may be more reliable when preformed on whole blood samples. We believe that it is important to continue this work so that we may investigate the usefulness and potential applications of thromboelastography in the evaluation of bleeding and thrombosis.

The classical treatment scheme for medulloblastoma (MB) is based on a tri-therapy approach consisting of surgical tumor resection, craniospinal axis radiation and chemotherapy. With current treatments relying mainly on non-specific cytotoxic therapy, a better understanding of the mechanisms underlying resistance to these treatments is important in order to improve their effectiveness. In this study, we report that stimulation of DAOY with HGF resulted in the protection of these cells against etoposide-induced apoptosis, this anti-apoptotic effect being correlated with an increase in the expression of tissue factor (TF), the initiator of the extrinsic pathway of coagulation. HGF-mediated protection from apoptosis was abolished by a c-Met inhibitor as well as by siRNA-mediated reduction of TF levels, implying a central role of Met-dependent induction of TF expression in this process. Accordingly, stimulation of DAOY with FVIIa, the physiological ligand of TF, also resulted in a significant protection from etoposide-mediated cytotoxicity. Overall, our results suggest the participation of the haemostatic system to drug resistance in MB and may thus provide novel therapeutic approaches for the treatment of these tumors.