Reduced doses of emicizumab achieve good efficacy: Results from a national-wide multicentre real-world study in China.

INTRODUCTION: Reduced doses of emicizumab improve the affordability among patients in developing countries. However, the relationship between variant dose selection and efficacy in the real world of China is still unclear. AIM: This study aimed to investigate the efficacy and safety of emicizumab especially in those on reduced dose regimens in a real-world setting. METHODS: We carried out a multicentre study from 28 hospitals between June 2019 and June 2023 in China and retrospectively analysed the characteristics including demographics, diagnosis, treatment, bleeding episodes, and surgical procedures. RESULTS: In total, 127 patients with haemophilia A, including 42 with inhibitors, were followed for a median duration of 16.0 (IQR: 9.0-30.0) months. Median age at emicizumab initiation was 2.0 (IQR: 1.0-4.0) years. Median (IQR) consumption for loading and maintenance was 12.0 (8.0-12.0) and 4.2 (3.0-6.0) mg/kg/4 weeks, respectively. While on emicizumab, 67 (52.8%) patients had no bleeds, whereas 60 (47.2%) patients had any bleeds, including 26 with treated bleeds. Compared to previous treatments, patients on emicizumab had significantly decreased annualized bleeding rate, annualized joint bleeding rate, target joints and intracerebral haemorrhage. Different dosages had similar efficacy except the proportion of patients with treated spontaneous bleeds and target joints. Adverse events were reported in 12 (9.4%) patients. Postoperative excessive bleeding occurred following two of nine procedures. CONCLUSION: This is the largest study describing patients with HA receiving emicizumab prophylaxis on variant dose regimens in China. We confirmed that nonstandard dose is efficacious and can be considered where full-dose emicizumab is ill affordable.

Desmopressin (DDAVP) use in patients with von Willebrand disease: A single-centre retrospective review of test response and clinical outcomes.

INTRODUCTION: Peri-procedural management of von Willebrand disease (VWD) utilizes von Willebrand factor (VWF) concentrates or desmopressin (DDAVP) to increase VWF levels. DDAVP is safe, easily administered, and inexpensive. Currently, a consensus definition for adequate DDAVP response is lacking, and outcomes of peri-procedural DDAVP use in VWD patients are seldom reported. AIM: This single-centre retrospective review aims to characterize DDAVP-responsiveness and assess clinical outcomes of peri-procedural DDAVP use in VWD. PATIENTS AND METHODS: We reviewed records for all our adult VWD patients (age ≥18 years) who underwent DDAVP challenge testing between January 2007 and January 2022. DDAVP-responsiveness was assessed using six definitions. Bleeding outcomes following procedures covered by DDAVP were classified as excessive or expected bleeding. RESULTS: Eighty-four of 94 (89.4%) patients were DDAVP-responsive by our definition (1-h VWF Activity/Factor VIII ≥0.50 IU/mL). However, the proportion of DDAVP-responders varied from 53.2% to 91.5%, depending on the literature definition used. Ninety-nine procedures pre-treated with DDAVP were performed during the study period. Eighty-six (86.7%) procedures (31 major; 55 minor) were covered with only DDAVP ± tranexamic acid (TXA). Excessive bleeding occurred following 4/31 major procedures and 2/55 minor procedures (both performed in a single patient with a bleeding score of 16). When covered with DDAVP+Factor ± TXA, one each of 10 major and 3 minor procedures (performed in 2 patients with bleeding scores 15-16) resulted in post-procedural bleeding. CONCLUSIONS: Peri-procedural DDAVP prophylaxis appears to be effective among individuals with VWD. Beyond DDAVP-responsiveness, patient bleeding history and procedure invasiveness should be considered in determining suitability for DDAVP prophylaxis.

Women and girls with haemophilia: A retrospective cohort study in China.

INTRODUCTION: Women and girls with haemophilia (WGH) may have spontaneous/traumatic bleeding similar to that in males with haemophilia, and in addition excessive bleeding during menstruation and delivery. AIM: To characterize WGH in China and provide guidance for better management. METHODS: We retrospectively analysed the characteristics of WGH registered in the Haemophilia Treatment Center Collaborative Network of China (HTCCNC) Registry, including demographics, diagnosis and treatment, bleeding characteristics, obstetrical and gynaecological experiences, and surgical history. RESULTS: A total of 61 females had confirmed haemophilia. Diagnosis and treatment were typically delayed, longer in mild haemophilia than in severe and moderate. The most frequently reported bleeding manifestations were haemarthrosis in severe and moderate patients, and cutaneous bleeding in mild patients. Among 45 postmenarcheal WGH, 21 (46.7%) had history of heavy menstrual bleeding, but only three received treatments. Prenatal diagnosis and management of perinatal haemorrhage were inadequate. Of 34 deliveries in 30 women, nine deliveries were complicated by postpartum haemorrhage, and 22 offspring carried mutations causing haemophilia. Forty-four surgical procedures were performed in 29 patients. Those procedures receiving preoperative coagulation factors coverage were significantly less likely to have excessive bleeding than those who did not (P = .003). CONCLUSION: This is the first and largest study describing WGH in China. There are currently deficiencies in the identification, diagnosis, and management of these patients. Improving health insurance policies, establishing haemophilia centres, and multidisciplinary teams for bleeding and perinatal or perioperative management will help reduce morbidity and mortality.

Factor IX inhibitors in haemophilia B: A report of National Haemophilia Registry in China.

INTRODUCTION: The development of inhibitors against factor FIX (FIX) is the most serious complication of FIX replacement therapy in haemophilia B (HB) patients. Currently, only few cohorts of HB inhibitor patients have been reported worldwide. AIM: This Chinese nationwide study of HB inhibitor patients explored their risk factors for FIX inhibitor development and experience on their management. METHODS: We retrospectively analysed patient characteristics, F9 genotypes, treatment strategies and outcomes of HB inhibitor patients registered to the Chinese National Registry and Patient Organization Registry. RESULTS: Forty-four unique HB inhibitor patients were identified in 4485 unique HB patients registered by year 2021 to the two Registries. Inhibitor diagnosis were usually delayed and the low prevalence (.98%) may suggest some inhibitor patients were not identified. Their median age at inhibitor diagnosis was 7.5 (IQR, 3.0-14.8) years. Most patients (95.5%) had high-titre inhibitors. Allergic/Anaphylactic reactions occurred in 59.1% patients. Large deletions and nonsense mutations were the most common F9 mutation types in our FIX inhibitor patients. Patients with large F9 gene deletions were more likely to develop inhibitors (p = .0002), while those with missense mutations had a low risk (p < .0001). Thirteen (29.5%) patients received immune tolerance induction (ITI) therapy using low-dose prothrombin complex concentrate regimens. Twelve completed ITI with three (25.0%) achieving success. Nephrotic syndrome developed in two (16.7%) patients during ITI. CONCLUSION: This study reports the largest Chinese cohort of HB inhibitor patients. Large deletions were most significantly associated with inhibitor development. Low-dose ITI might be feasible for FIX inhibitor eradication.

Novel manifestations of immune dysregulation and granule defects in gray platelet syndrome.

Gray platelet syndrome (GPS) is a rare recessive disorder caused by biallelic variants in NBEAL2 and characterized by bleeding symptoms, the absence of platelet α-granules, splenomegaly, and bone marrow (BM) fibrosis. Due to the rarity of GPS, it has been difficult to fully understand the pathogenic processes that lead to these clinical sequelae. To discern the spectrum of pathologic features, we performed a detailed clinical genotypic and phenotypic study of 47 patients with GPS and identified 32 new etiologic variants in NBEAL2. The GPS patient cohort exhibited known phenotypes, including macrothrombocytopenia, BM fibrosis, megakaryocyte emperipolesis of neutrophils, splenomegaly, and elevated serum vitamin B12 levels. Novel clinical phenotypes were also observed, including reduced leukocyte counts and increased presence of autoimmune disease and positive autoantibodies. There were widespread differences in the transcriptome and proteome of GPS platelets, neutrophils, monocytes, and CD4 lymphocytes. Proteins less abundant in these cells were enriched for constituents of granules, supporting a role for Nbeal2 in the function of these organelles across a wide range of blood cells. Proteomic analysis of GPS plasma showed increased levels of proteins associated with inflammation and immune response. One-quarter of plasma proteins increased in GPS are known to be synthesized outside of hematopoietic cells, predominantly in the liver. In summary, our data show that, in addition to the well-described platelet defects in GPS, there are immune defects. The abnormal immune cells may be the drivers of systemic abnormalities such as autoimmune disease.

Eradication of FIX inhibitor in haemophilia B children using low-dose immune tolerance induction with rituximab-based immunosuppressive agent(s) in China.

INTRODUCTION: Development of haemophilia B inhibitors (HBI) results in the ineffectiveness of FIX replacement therapy. Inhibitor eradication by immune tolerance induction (ITI) is therefore necessary. In HBI, ITI even at high FIX dose is less effective and has a higher risk of severe complications. AIM: To characterize clinical features and outcome of ITI on HBI. METHODS: This retrospective study was conducted in Haemophilia Paediatric Comprehensive Care Centre of China. We used low-dose ITI (25-50 FIX IU/kg/three-times-weekly to every-other-day) with domestic prothrombin complex concentrate (PCC), combined with two successive immunosuppressive (IS) regimens. RESULTS: Sixteen HBI children, representing 5.7% of all and 14.4% of our severe registered HB patients, were enroled. Seven cases reported allergic reactions (ARs) proximal to inhibitor development. The historic peak inhibitor titre was median 54.2 (range 4.7-512) BU, and 15 (93.8%) had high-titre inhibitors. Twelve patients adherent to ITI were analysable. Of the nine ITI patients who received rituximab/prednisone (IS Regimen-1), four achieved tolerization in 1.4-43.3 months. Two subsequently relapsed but re-tolerized after a second course of IS Regimen-1. During ITI, the median treated bleed was .39/month (82.7% reduction from before ITI), and the incidence of AR and nephrotic syndrome (NS) complications was each at 22% (2/9). Three ITI patients received modified 'Beutel' protocol (IS Regimen-2) using multiple-IS-drugs, and two had rapid tolerization (.8 and 1.8 months). CONCLUSIONS: Inhibitor eradication could be achieved by low-dose ITI protocol using PCC combined with IS. Larger studies are needed to confirm if ITI with IS Regimen-2 is more effective with less complications.

Current status of haemophilia inhibitor management in mainland China: a haemophilia treatment centres survey on treatment preferences and real-world clinical practices.

To investigate the current experience and expertise for haemophilia inhibitor patient management in haemophilia treatment centres (HTCs) in mainland China. Questionnaires were distributed to 'tertiary tier A' hospital HTCs across China to collect information on treatment preferences for bleeding control, prophylaxis and inhibitor eradication, as well as their regimens in real-world clinical practice. Of 40 questionnaires distributed, 39 were returned. In all, 38 were analysable for treatment preferences and 34 for actual clinical practice. For haemostatic treatment, 76·3% (29/38) HTCs preferred activated recombinant human Factor VII (rFVIIa). In clinical practice, the most widely used by-pass agent was prothrombin complex concentrate (26 HTCs). Although 65·8% (25/38) of HTCs believed prophylaxis treatment was necessary, it was prescribed in only 12. Similarly, 65·8% (25/38) of HTCs believed immune tolerance induction (ITI) therapy was necessary but only 14·8% (92/622) of patients in 19 HTCs received low-dose ITI treatment. HTCs in relatively economically developed cities (with higher-than-average per-capita gross domestic product) had better access to haemostatic treatment, coagulation testing and were more likely to provide prophylaxis and ITI in practice. The present survey showed there were gaps in haemophilia inhibitor care between the HTC physicians' preferences and their actual clinical practice. More specific care guidelines, education and clinical decision support tools are needed to guide clinical practice.

Patients with haemophilia A with inhibitors in China: a national real-world analysis and follow-up.

The development of alloantibodies (inhibitors) against coagulation factor VIII (FVIII) is the most serious complication of FVIII replacement therapy in patients with haemophilia A (HA). We carried out a nationwide study focussing on patients with HA with inhibitors in China to evaluate the condition and management of this population. The study retrospectively analysed patient characteristics, clinical history, manifestation, treatment strategy as well as individual haemophilia care of 493 patients with inhibitors (466 with severe HA and 27 with non-severe HA) registered all over China. The median (interquartile range) age at diagnosis of FVIII inhibitors was 13 (5-28) years in patients with severe HA and 24 (10·5-39·5) years in patients with non-severe HA. Most patients (85%) had high-titre inhibitors. Prothrombin complex concentrate and recombinant activated coagulation factor VII were used respectively in 76·2% and 29·2% of patients for acute bleeding. Only 22·3% of patients underwent immune tolerance induction (ITI) treatment, of whom 64·9% achieved negative inhibitor titre. In patients who did not undergo ITI, the inhibitors turned negative in 17·7%, and patients with low peak inhibitor titre were more likely to acquire negative titre spontaneously (odds ratio 11·524, 95% confidence interval 5·222-25·432; P = 0·000). We recorded that 3·2% of the patients died from haemophilia-related life-threatening bleeding.

The Function of extravascular coagulation factor IX in haemostasis.

INTRODUCTION: The majority of clotting factor IX (FIX) resides extravascularly, in the subendothelial basement membrane, where it is important for haemostasis. AIM: We summarize preclinical studies demonstrating extravascular FIX and its role in haemostasis and discuss clinical observations supporting this. We compare the in vivo binding of BeneFIX® and the extended half-life FIX, Alprolix® , to extravascular type IV collagen (Col4). METHODS: Three mouse models of haemophilia were used: the FIX knockout as the CRM- model and two knock-in mice, representing a CRM+ model of a commonly occurring patient mutation (FIXR333Q ) or a mutation that binds poorly to Col4 (FIXK5A ). The murine saphenous vein bleeding model was used to assess haemostatic competency. Clinical publications were reviewed for relevance to extravascular FIX. RESULTS: CRM status affects recovery and prophylactic efficacy. Prophylactic protection decreases ~5X faster in CRM+ animals. Extravascular haemostasis can explain unexpected breakthrough bleeding in patients treated with some EHL-FIX therapeutics. In mice, both Alprolix® and BeneFIX® bind Col4 with similar affinities (Kd~20-40 nM) and show dose-dependent recoveries. As expected, the concentration of binding sites in the mouse calculated for Alprolix® (574 nM) was greater than for BeneFIX® (405 nM), due to Alprolix® binding to both Col4 and the endothelial cell neonatal Fc receptor. CONCLUSION: Preclinical and clinical results support the interpretation that FIX plays a role in haemostasis from its extravascular location. We believe that knowing the CRM status of haemophilia B patients is important for optimizing prophylactic dosing with less trial and error, thereby decreasing clinical morbidity.

Long-term joint outcomes of regular low-dose prophylaxis in Chinese children with severe haemophilia A.

OBJECTIVES: To explore the long-term joint outcomes of low-dose prophylaxis in Chinese children with severe haemophilia A and to analyse their related factors. METHODS: We retrospectively analysed follow-up data from 21 severe haemophilia A children on regular low-dose prophylaxis for 6-10 years. We used International Prophylaxis Study Group magnetic resonance imaging score (IPSG MRI score), Hemophilia Joint Health Score (HJHS), number of target joints, and Hemophilia-Specific Quality of Life Index (Haemo-QoL) to evaluate joint outcomes. Factors associated with these outcomes were evaluated by statistical analysis. RESULTS: (1) The children were 1.75 to 17 years age at prophylaxis initiation. Median prophylactic factor VIII dose was 22.9 IU/kg per week. (2) At the end of follow-up: (a) The total IPSG MRI scores were 2-24 with 90.5% children exhibiting moderate to severe joint involvement (score 7-24); (b) The HJHS ranged 2-27, with 0-10 for 46.7% children and >10 for 53.3% children. There was a positive correlation between the MRI score and HJHS (p < .05); (c) Compared to their on-demand treatment period before prophylaxis, target joints numbers decreased, and no child needed auxiliary devices to walk; (d) Joint outcomes were positively correlated with the age at initiation of low-dose prophylaxis (p < .05) and negatively correlated with the treatment dose. CONCLUSION: Long-term low-dose prophylaxis had positive effect on joint outcomes compared with on-demand treatment. However, a certain degree of joint damage remained in all children indicating the need for improving the current strategy of low-dose prophylaxis.

Factor product utilization and health outcomes in patients with haemophilia A and B on extended half-life concentrates: A Canadian observational study of real-world outcomes.

INTRODUCTION: Recombinant factors VIII and IX Fc (rFVIIIFc/rFIXFc) became available in Canada in 2016 and were the only extended half-life (EHL) factor concentrates available in Canada until 2018. OBJECTIVES: We aim to describe the change in product utilization in Canadians who switched to rFVIIIFc/rFIXFc. METHODS: This prospective and retrospective cohort study enrolled males aged ≥6 years with moderate or severe haemophilia who switched to rFVIIIFc/rFIXFc and those who remained on standard half-life (SHL) between 2016 and 2018. Factor utilization and annualized bleeding rates (ABR) were collected at baseline, 1-year and 2-years. Due to low prospective enrolment (n = 25 switchers), prospective and retrospective data were pooled. RESULTS: 125 switchers (93 rFVIIIFc, 32 rFIXFc) and 33 non-switchers were included. The median age was 17 (rFVIIIFc) and 38 years (rFIXFc). Prior to switch, over 80% were on prophylaxis. There was a statistically significant reduction in the prescribed weekly prophylactic dose after the switch to rFVIIIFc/rFIXFc for all age groups, with a corresponding reduction (15-16%) in actual annualized FIX utilization in switchers (combined adults and children) to rFIXFc, and a smaller non-significant reduction in actual annualized FVIIII utilization (7%) in children who switched to rFVIIIFc. A significant reduction in the median ABR was only observed in children who switched to rFVIIIFc, but not in adults who switched to rFVIIIFc or rFIXFc. CONCLUSION: Switching from SHL to EHL products led to a small reduction in factor utilization, while preserving a low ABR in children and adults with haemophilia. Further patient-reported outcomes data will further elucidate the role of EHL in the haemophilia landscape.

Haemophilia care in China: Achievements in the past decade.

There is a large population of people with haemophilia in China. However, the development of haemophilia care in China lagged far behind developed countries and was unbalanced across different regions. With the establishment of the Hemophilia Treatment Center Collaborative Network of China (HTCCNC) in 2004 and its collaboration with the Chinese government, the World Federation of Haemophilia (WFH), non-profit foundations, industries, and experts from other countries, haemophilia care in China have made considerable strides in building capacity. The HTCCNC helped develop clinics throughout the country, promote multidisciplinary care, promote prophylaxis (albeit low-dose), advance clinical evaluation and treatment, and research. With many collaborative efforts in the past decade, haemophilia care in China has entered a new stage of development. In this review, we summarize these major achievements and efforts within the last decade.

Severe haemophilia A children on low-dose tertiary prophylaxis showed less joint deterioration and better maintenance of functional independence than children on on-demand treatment: A 6-year follow-up study.

BACKGROUND: In countries with limited resource, haemophilia patients have to choose low-dose prophylaxis or on-demand treatment (ODT) because of economic constraints. Whether low-dose prophylaxis can achieve better joint function outcome than ODT over long-term remains unclear. AIM: To investigate the long-term effect of low-dose tertiary prophylaxis versus ODT on joint health in severe haemophilia A children. METHODS: This was a retrospective study. We enrolled and followed 34 severe haemophilia boys in China receiving on-demand treatment (n = 18) or low-dose prophylaxis (10-15 IU/kg, 2-3 times per week) for a medium-term (6-18 months, n = 9) or longer-term (19-30 months, n = 7). We evaluated their haemophilia joint health score (HJHS) 2.1 and functional independence score in haemophilia (FISH) at baseline and at their 6-year follow-up visits. Their annual bleeding rate (ABR) and annual joint bleeding rate (AJBR) were also recorded. RESULTS: During the 6-year follow-up period, ABR and AJBR were similar between the 2 prophylaxis groups, with each of the 2 prophylaxis group rates being significantly better (lower) than the ODT group (P < .05). Compared to baseline values, evaluation at 6-year follow-up showed HJHS improvement in both prophylaxis groups, although significantly (P < .05) only in the longer-term prophylaxis group. The FISH score showed insignificant change in patients in each prophylaxis cohort, compared to significant worsening (P < .05) in the ODT group. CONCLUSION: Low-dose tertiary prophylaxis reduced ABR and AJBR of children with severe haemophilia and better maintained their functional independence by the FISH over the long term. Longer-term prophylaxis also improved their joint health status by the HJHS.

Management of haemophilia patients in the COVID-19 pandemic: Experience in Wuhan and Tianjin, two differently affected cities in China.

OBJECTIVE: To identify lessons learned from haemophilia care experience in Wuhan (COVID-19 outbreak epicenter in China) and Tianjin (with relatively low COVID-19 incidence) in the pandemic. METHODS: We compared the challenges in haemophilia management attributed to local COVID-19 containment policies, healthcare resource availability, clotting factors supply, daily living restrictions and coping strategies employed. RESULTS: Wuhan was in lockdown with strict traffic controls, enforced quarantine and overwhelmed resources. Tianjin was in relatively relaxed countermeasures to COVID-19. In Wuhan, haemophilia treatment (for bleeding, prophylaxis, multidisciplinary team care, immune tolerance induction) and patient education were severely affected, while the challenges in Tianjin were less. In both cities, patients' fear for COVID-19 infection also affected their management. Coping strategy in Wuhan included channelling of clotting factors supply from hospitals to nine pharmacies; timely transfers of in-need patients to healthcare facilities by a volunteer service network jointly coordinated by the government, hospitals and the community. Although factor concentrate supply in each city was adequate, patients still worried whether there would be enough supply to last through the pandemics. Consequently, many downgraded their treatment regimens resulting in increased bleeding episodes. In both cities, telemedicine was promoted for patient care and education. CONCLUSIONS: The COVID-19 pandemic had varying adverse impacts on haemophilia care depending on the local infection incidence. Our experience suggests that haemophilia management strategies in the pandemic need to be established according to the local virus containment/mitigation policies, daily living restrictions and resource availability.

Bleeding assessment in haemophilia carriers-High rates of bleeding after surgical abortion and intrauterine device placement: A multicentre study in China.

INTRODUCTION: An increased bleeding tendency has been shown in female haemophilia carriers compared to healthy females. Bleeding assessment tools (BATs) have mainly been performed in western cultures. It is unclear how they perform in populations with different healthcare, health/wellness concepts and awareness, as well as family planning practices. AIM: To (a) describe and compare the bleeding symptoms in carriers with healthy females, particularly for bleeding after surgical abortion and intrauterine device (IUD) placement which are performed frequently for family planning in China; (b) quantify scores of International Society on Thrombosis and Haemostasis Bleeding Assessment Tool (ISTH-BAT) and Chinese-BAT (C-BAT) developed to include surgical abortion and IUD placement as separate categories in Chinese haemophilia carriers; (c) correlate bleeding scores (BS) with factor levels. METHODS: We conducted a multicentre, cross-sectional study on obligate haemophilia carriers and healthy controls using ISTH-BAT and C-BAT. RESULTS: We enrolled 125 haemophilia carriers and 106 controls. Carriers, compared to controls, had significantly higher median BS (3 vs 1 by both ISTH-BAT and C-BAT) and lower factor level (63.5 vs 101.8 IU/dL). Bleeding after surgical abortion and IUD placement was significantly associated with carrier status. Bleeding scores from neither ISTH-BAT nor C-BAT showed significant correlation with factor levels. CONCLUSION: Haemophilia carriers in China experienced abnormal bleeding. Unique to the Chinese carriers is significant bleeding after surgical abortion (3rd highest incidence of bleeding symptom) and IUD placement (4th highest). However, both ISTH-BAT and C-BAT exhibited no correlation between BS and factor levels in this population and neither could identify carriers with low factor level (of <50 IU/dL).

Healthcare professionals in the 'tainted blood' era in Canada: Their forgotten emotions.

INTRODUCTION: During the 1970s and early 1980s, Canada's comprehensive care haemophilic programs were established. Newer therapies led to a rapid increase in quality of life and expected life span for persons with haemophilia (PWH). The outlook was bright. However, beginning in 1982, the appearance of HIV/AIDS transmitted by treatment products led to the 'tainted blood' era with its devastating impact on PWH, recently highlighted in the Canadian Broadcasting Corporation mini-series 'Unspeakable'. What has received less notice is how the healthcare professionals (HCP) managing these patients then were affected. AIM: To report the emotional effects of that era on HCPs. METHODS: In developing an oral history of haemophilic care in Canada we have interviewed 76 HCPs, the majority of whom had worked in haemophilic clinics during that era. During each interview, we asked the interviewee to reflect on what this did to haemophilic care and to him/herself. The interview responses were analysed. RESULTS: HCPs have been markedly affected by the events of the 1980s with feelings that persist more than 30 years later. Most related to the loss of so many of their patients and the inability to alter the rapidly changing course of events at the time. CONCLUSION: The 'tainted blood' era had persistent strong emotional effects on HCPs. They were helpless to stop or to mitigate the devastating epidemics. Wellness support programs were less well developed then. While the focus is in the Canadian context, we suggest that a parallel can be drawn within haemophilic communities in other countries.

Alloimmunization in Congenital Deficiencies of Platelet Surface Glycoproteins: Focus on Glanzmann's Thrombasthenia and Bernard-Soulier's Syndrome.

Glanzmann's thrombasthenia (GT) and Bernard-Soulier's syndrome (BSS) are well-understood congenital bleeding disorders, showing defect/deficiency of platelet glycoprotein (GP) IIb/IIIa (integrin αIIbß3) and GPIb-IX-V complexes respectively, with relevant clinical, laboratory, biochemical, and genetic features. Following platelet transfusion, affected patients may develop antiplatelet antibodies (to human leukocyte antigen [HLA], and/or αIIbß3 in GT or GPIb-IX in BSS), which may render future platelet transfusion ineffective. Anti-αIIbß3 and anti-GPIb-IX may also cross the placenta during pregnancy to cause thrombocytopenia and bleeding in the fetus/neonate. This review will focus particularly on the better studied GT to illustrate the natural history and complications of platelet alloimmunization. BSS will be more briefly discussed. Platelet transfusion, if unavoidable, should be given judiciously with good indications. Patients following platelet transfusion, and women during and after pregnancy, should be monitored for the development of platelet antibodies. There is now a collection of data suggesting the safety and effectiveness of recombinant activated factor VII in the management of affected patients with platelet antibodies.

Characterization of aberrant splicing of von Willebrand factor in von Willebrand disease: an underrecognized mechanism.

Approximately 10% of von Willebrand factor (VWF) gene mutations are thought to alter messenger RNA (mRNA) splicing through disruption of consensus splice sites. This mechanism is likely underrecognized and affected by mutations outside consensus splice sites. During VWF synthesis, splicing abnormalities lead to qualitative defects or quantitative deficiencies in VWF. This study investigated the pathologic mechanism acting in 3 von Willebrand disease (VWD) families with putative splicing mutations using patient-derived blood outgrowth endothelial cells (BOECs) and a heterologous human embryonic kidney (HEK 293(T)) cell model. The exonic mutation c.3538G>A causes 3 in-frame splicing variants (23del, 26del, and 23/26del) which cannot bind platelets, blood coagulation factor VIII, or collagen, causing VWD through dominant-negative intracellular retention of coexpressed wild-type (WT) VWF, and increased trafficking to lysosomes. Individuals heterozygous for the c.5842+1G>C mutation produce exon 33 skipping, exons 33-34 skipping, and WT VWF transcripts. Pathogenic intracellular retention of VWF lacking exons 33-34 causes their VWD. The branch site mutation c.6599-20A>T causes type 1 VWD through mRNA degradation of exon 38 skipping transcripts. Splicing ratios of aberrant transcripts and coexpressed WT were altered in the BOECs with exposure to shear stress. This study provides evidence of mutations outside consensus splice sites disrupting splicing and introduces the concept that VWF splicing is affected by shear stress on endothelial cells.

Desmopressin in non-severe haemophilia A: Test-response and clinical outcomes in a single Canadian centre review.

INTRODUCTION: Desmopressin is an effective haemostatic agent for patients with non-severe haemophilia A; however, response may differ between patients of similar severity. Responsiveness is classified based on various cut-off values for plasma levels of FVIII post-desmopressin administration. Patients may be classified differently depending on the values chosen. AIM: To classify desmopressin response in non-severe haemophilia A patients with respect to current test-response definitions. Also, to characterize relationships between test response and clinical outcome of desmopressin use. METHODS: Current desmopressin test-response definitions were obtained from the literature. We adopted peak FVIII level (at 1 hour post-administration) ≥50 IU/dL and <20 IU/dL as complete and no response, respectively, thereby satisfying most reported definitions. Test-responses and clinical outcomes of use between 2007 and 2017 for adult mild/moderate haemophilia A patients were reviewed and correlated. RESULTS: All patients classified as complete responders (n = 31; peak FVIII ≥50 IU/dL) and the majority of partial responders (n = 11; peak FVIII ≥20 to <50 IU/dL) had good clinical outcomes after desmopressin use for a variety of bleeding episodes and procedures. Two non-responders (peak FVIII <20 IU/dL) given desmopressin for minor bleeding/procedures also had good clinical outcomes. One patient with a partial test-response (peak FVIII 23 IU/dL) required additional factor concentrate to achieve haemostasis. CONCLUSIONS: Based on our review, we suggest that the determination of desmopressin responsiveness should consider both the change in plasma FVIII levels as well as clinical outcomes associated with prior therapeutic use.