Comprehensive care for hemophilia and other inherited bleeding disorders.

The World Federation of Hemophilia (WFH) states in its Guidelines for the Management of Hemophilia, Second Edition [1], that people with hemophilia are best managed in a comprehensive care setting. That team is typically comprised of a core group including a hematologist, nurse coordinator, physiotherapist, social worker, specialized lab technologist and data manager, and as needed, by other specialists. Hemophilia is an X-linked congenital bleeding disorder caused by a deficiency of coagulation factor VIII (FVIII) in hemophilia A or factor IX (FIX) in hemophilia B. There are a number of other disorders that are now typically treated in these comprehensive care centers including von Willebrand disease (VWD), rare factor deficiencies (I, II, V, V & VIII, VII, X, XI and XIII), and inherited platelet function disorders. Models of comprehensive care delivery for hemophilia and other inherited bleeding disorders were first defined in the 1960s and have been in constant evolution ever since. Comprehensive care for hemophilia and other inherited bleeding disorders was made possible by the discovery of cryoprecipitate for the treatment of hemophilia A in the mid-1960s and, in the decade that followed, the development of lyophilized clotting factor concentrates. It was quickly realized that treatment at home was far preferable to frequent visits to Emergency Departments or out-patient. Tragically, the same clotting factor concentrates that revolutionized treatment and dramatically improved quality of life exposed thousands of people with hemophilia to HIV-AIDS and hepatitis C in the late 1970s and 1980s [2]. The model of comprehensive care was forced to add specialists in infectious disease and hepatology. At the same time, the crisis accelerated the development of recombinant FVIII and IX clotting factors; these entered the clinic in 1993 and 1997 respectively. The proven safety of both recombinant and plasma-derived products spurred on the expansion of prophylactic care to more patients. Today, with the success of a comprehensive care model that keeps patients out of the hospital (and out of sight), and promises a normal lifespan, there is an emerging impression among many health system managers that the problem of hemophilia is "solved." In 2019, however, even the best care and treatment remains highly burdensome and not entirely efficacious. Emerging innovative therapies are promising yet dramatically different in their modes of action, dosing and administration. Much of what has been learned in terms of management of the disease over the last 50 years may no longer be relevant. Rather than one type of treatment for all, there may well be many different therapies. Comprehensive care centres will not become obsolete. It will remain critically important that specialized staff be able to foster long-term relationships with patients and their families. Indeed, they will need to expand their knowledge and expertise in order to be able to continue to deliver the standards of care so carefully developed since the 1960s.

Diagnosing von Willebrand disease: a short history of laboratory milestones and innovations, plus current status, challenges, and solutions.

von Willebrand disease (VWD) is a disorder characterized by deficiency of, or defects in, von Willebrand factor (VWF). VWD was originally identified by Erik Adolf von Willebrand, who in early 1924 investigated a large family suffering from a bleeding disorder that seemed to differ from hemophilia. Erik von Willebrand undertook some initial laboratory investigations to conclude the involvement of a plasma factor, the lack of which prolonged the bleeding time, but failed to impair coagulation times and clot retraction. By the end of the 1960s, VWD was accepted as a combined deficiency of factor VIII (FVIII) and another plasma factor responsible for normal platelet adhesion. Just how these two functions were related to each other was less clear and the diagnostic tests available at the time were poorly reproducible, cumbersome, and unreliable; thus, VWD was poorly delineated from other coagulation and platelet disorders. The early 1970s saw a revolution in diagnostics when ristocetin was identified to induce platelet aggregation, and this formed the basis of the first consistent and reliable VWF "activity" test, permitting quantification of the platelet adhesive function missing in VWD. Concurrently, immunoprecipitating techniques specific for VWF were defined, and the application of such technologies permitted a clearer understanding of both VWF and VWD heterogeneity. Continued exploration of the structure and function of VWF contributed greatly to the understanding of platelet physiology, ligand receptor interaction and pathways of cellular interaction and activation. Recently, additional assays evaluating other functions of VWF, including collagen binding, platelet glycoprotein Ib binding, and FVIII binding, have improved the diagnosis of VWD. The purpose of this narrative review is to explore the history of phenotypic VWD diagnostics, with a focus on laboratory milestones from the past as well highlighting recent and ongoing innovations, and ongoing challenges and possible solutions.

[Von Willebrand and his factor]. / Von Willebrand en zijn factor.

Erik Adolf von Willebrand (1870-1949) studied medicine in Helsinki, where he subsequently joined the staff at the Deaconess Hospital. Haematological disorders were his main interest. In 1924 he was consulted about 5-year-old Hjördis S. She suffered from a severe bleeding disorder, as did six of her ten siblings; three of her sisters had died. In a Finnish article in a Journal in 1926 (in the Swedish language) he plotted the family pedigree (bleeding disorder in three preceding generations, on the part of both parents). Von Willebrand also distinguished the disorder from haemophilia and thrombopathies with purpura. His conjecture that the disorder was a special form of thrombocyte dysfunction would eventually be borne out, though the key factor is severe deficiency of a specific plasma protein. In milder, autosomal dominant forms of the disease, the protein is partly deficient or abnormal.

Haemate P von Willebrand factor/factor VIII concentrate: 25 years of clinical experience.

Although von Willebrand disease (VWD) has a very long history, our understanding and treatment of the bleeding disorder has only evolved during the past 50 years or so. It was not until the 1920s that VWD was first recognized as a disease separate from that of classical haemophilia. It then took another 30 years before the first effective treatment was developed. Since then, the medical management of VWD has evolved considerably, but not without its ups and downs. One of the key milestones in the evolution of the treatment of VWD was the development of Haemate P/Humate-P (CSL Behring) - the first virus-inactivated factor VIII plasma product. For 25 years, this concentrate has demonstrated excellent clinical efficacy and safety for patients with VWD and for those with haemophilia. This article provides an historical overview of the early landmark efforts to ensure a safe plasma-derived replacement product and outlines the clinical evolution in the use of Haemate P.

The use of desmopressin in von Willebrand disease: the experience of the first 30 years (1977-2007).

The aim of the treatment for von Willebrand disease (VWD) is to correct the dual defect of haemostasis, i.e. the abnormal platelet adhesion as a result of reduced and/or dysfunctional von Willebrand factor (VWF) and the abnormal coagulation expressed by low levels of factor VIII (FVIII). Correction of both deficiencies can be achieved by administering the synthetic peptide desmopressin (DDAVP) or, in cases unresponsive to this agent, the plasma concentrates containing VWF and FVIII (VWF/FVIII). DDAVP is the treatment of choice for type 1 VWD because it can induce release of normal VWF from cellular compartments, but the drug can be clinically useful also in other VWD types, including acquired von Willebrand syndrome (AVWS). A test dose of DDAVP at the time of diagnosis is recommended to establish the individual patterns of biological response and to predict clinical efficacy during bleeding and surgery. DDAVP is not effective in VWD type 3 and in severe forms of VWD 1 and 2. It can induce transient thrombocytopenia in patients with VWD type 2B. The results of several retrospective studies on the use of DDAVP in VWD management have been reported by many authors in different countries for the last 30 years. However, despite the widespread use of DDAVP in the treatment of VWD, there are only a few prospective clinical trials in a large number of cases on DDAVP efficacy and safety aimed at determining benefits and limits of this therapeutic approach. An investigator-driven observational prospective study on clinical efficacy of DDAVP in 200 patients with VWD types 1 and 2 has been recently organized: the effectiveness and safety of DDAVP will be evaluated prospectively for 24 months during bleeding episodes and minor or major surgeries in the VWD patients who were exposed to an infusion trial at enrollment.

Erik von Willebrand.

In 1926, Erik von Willebrand, a Finnish physician, published the first manuscript describing a haemorrhagic disorder in people who were living on the Aland islands off the coast of Finland. This disorder is now known by the name of its discoverer. Since this early observation, von Willebrand disease has been extensively studied. Today, we know the structure and function of the von Willebrand factor and much of its molecular biology. With the availability of safe and effective products, the treatment of von Willebrand disease is continually improving.

The 80th anniversary of von Willebrand's disease: history, management and research.

The history of von Willebrand's disease (VWD) is fascinating because it demonstrates how good clinical observations, genetic studies and biochemical skills can improve basic understanding of a disease and its management. The continuous efforts of scientists and clinicians during the last 80 years have significantly improved the knowledge of von Willebrand factor (VWF) structure and function and the management of VWD. Diagnosis of phenotype and genotype is now available in many countries and treatment is becoming more specific according to the VWD type. Any therapeutic agents must correct the dual defect of haemostasis, i.e. the abnormal platelet adhesion due to reduced and/or dysfunctional and low levels of factor VIII (FVIII) associated with VWF defects. Desmopressin (DDAVP) is the treatment of choice for type 1 VWD because it induces release of VWF from cellular compartments. Plasma virally inactivated VWF concentrates containing FVIII are effective and safe in patients unresponsive to DDAVP. There are advanced plans to develop a recombinant VWF but this product will require the concomitant administration of FVIII for the control of acute bleeds. Basic research studies on cellular biology, biochemistry and immunology have confirmed the role of VWF as a crucial participant in both haemostasis and thrombosis as its main biological activity is to support platelet adhesion-aggregation in the circulation. Retrospective and prospective clinical research studies, including bleeding history and laboratory markers for diagnosis as well as the use of DDAVP and VWF concentrates to manage or prevent bleeds in patients with VWD have been essential to provide general guidelines for VWD management. The large number of publications quoting VWD and VWF emphasizes the important role of VWF in medicine.

A short history of diagnostic tests for von Willebrand disease: in memory of Barry Firkin (1930 to 2001) and Ted Zimmerman (1937 to 1988).

By the end of the 1960s, von Willebrand disease (vWD) was accepted as a combined deficiency of factor (F) VIII coagulation and a plasma factor responsible for normal platelet adhesion. Just how these two functions related to each other was unclear, and the diagnostic tests available at the time were poorly reproducible, cumbersome, and unreliable. As a consequence, the condition was poorly delineated from other coagulation and platelet disorders. In the early 1970s, ristocetin-induced platelet aggregation was described and formed the basis of the first consistent and reliable test that quantified the platelet adhesive function missing in vWD. Immunoprecipitating techniques specific for the molecule missing in vWD were defined. The application of these technologies allowed a clearer understanding of the heterogeneity of vWD and continues to form a basis for the diagnosis of this condition. Concurrently, exploration of the structure and function of von Willebrand factor (vWF) has contributed greatly to the understanding of platelet physiology, ligand receptor interaction, and pathways of cellular interaction and activation. Despite all of the progress during the last 35 years, including extensive developments in the field of molecular biology and genetics of vWD, the diagnosis of this condition in many, if not most cases, remains controversial. The final plasma level of vWF is influenced substantially by epigenetic and environmental factors. This natural heterogeneity is further compounded by significant imprecision of existing tests. As a consequence, defining vWD on the basis of a variation from the normal range alone is more than likely to be incorrect. The high frequency of a positive bleeding disorder in the normal population does not assist discrimination. It has been suggested that the diagnosis of mild type 1 vWD be discarded because it does not exhibit consistent linkage to the VWF gene and does not predict bleeding.

The evolving classification of von Willebrand disease.

The classification of von Willebrand disease (VWD) has been refined since its first description in the 1920s, as knowledge regarding clinical symptoms and tests of von Willebrand factor (VWF) activity and multimer composition have increased. Current molecular approaches have allowed better understanding of the biosynthesis and function of VWF, and made possible phenotype-genotype studies of VWD subtypes. Improved classification of this heterogeneous disorder based on reproducible correlations between specific genetic mutations and recognized phenotypes should aid in determining appropriate management of patients with VWD.

Enfermedad de von Willebrand adquirida: aspectos generales / Acquired von Willebrands disease: general aspects

La enfermedad de von Willebrand adquirida es una enfermedad hemorrágica poco común. Aproximadamente en la mitad de los casos se asocia con enfermedades linfoproliferativas y también se ha relacionado con trastornos mieloproliferativos, neoplasias, enfermedades inmunológicas, cardiovasculares y otras condiciones clínicas. Debe sospecharse en todos los pacientes que presenten una diátesis hemorrágica de aparición tardía sin historia personal o familiar de coagulopatía; los síntomas clínicos son similares a los de la enfermedad de von Willebrand congénita. Esta enfermedad parece tener una etiología multifactorial; en la mayoría de los pacientes afectados el factor von Willebrand (FvW) se sintetiza normalmente, sin embargo, es rápidamente removido del plasma a través de diferentes mecanismos, cuyo resultado final común es la disminución de los niveles circulantes de este factor. Los ensayos clásicos de laboratorio incluyen la exploración de la hemostasia primaria y las pruebas específicas para la determinación de la actividad antigénica y funcional del FvW. El tratamiento va dirigido en 2 direcciones principales: corregir episodios de sangrado agudo y tratar la enfermedad subyacente y condiciones asociadas(AU)

Type IIB von Willebrand disease: a paradox explains how von Willebrand factor works.

Type IIB is a variant form of von Willebrand disease in which a structural abnormality of von Willebrand factor (VWF) causes enhanced binding to the platelet glycoprotein Ib receptor. As a consequence of this functional alteration, there is a decrease in the concentration of the largest VWF multimers in plasma, and the platelet count may be episodically decreased as a consequence of microaggregation. The net result is an apparent paradox, since the presence of a hyperfunctional adhesive molecule in blood causes a bleeding tendency. Here I recall how my colleagues and I managed to understand what goes on in these patients.