Autoantibody inhibits binding of von Willebrand factor to glycoprotein Ib and collagen in multiple myeloma: recognition sites present on the A1 loop and A3 domains of von Willebrand factor

The Role of the von Willebrand Factor Collagen-Binding Assay (VWF:CB) in the Diagnosis and Treatment of von Willebrand Disease (VWD) and Way Beyond: A Comprehensive 36-Year History

The von Willebrand factor (VWF) collagen binding (VWF:CB) assay was first reported for use in von Willebrand diagnostics in 1986, by Brown and Bosak. Since then, the VWF:CB has continued to be used to help diagnose von Willebrand disease (VWD) (correctly) and also to help assign the correct subtype, as well as to assist in the monitoring of VWD therapy, especially desmopressin (DDAVP). However, it is important to recognize that the specific value of any VWF:CB is predicated on the use of an optimized VWF:CB, and that not all VWF:CB assays are so optimized. There are some good commercial assays available, but there are also some "not-so-good" commercial assays available, and these may continue to give the VWF:CB "a bad reputation." In addition to VWD diagnosis and management, the VWF:CB found purpose in a variety of other applications, from assessing ADAMTS13 activity, to investigation into acquired von Willebrand syndrome (especially as associated with use of mechanical circulatory support or cardiac assist devices), to assessment of VWF activity in disease states in where an excess of high-molecular-weight VWF may accumulate, and lead to increased (micro)thrombosis risk (e.g., coronavirus disease 2019, thrombotic thrombocytopenic purpura). The VWF:CB turns 37 in 2023. This review is a celebration of the utility of the VWF:CB over this nearly 40-year history.

Acquired von Willebrand syndrome in multiple myeloma

Acquired von Willebrand syndrome (AvWS) is an uncommon complication of multiple myeloma (MM), and it is believed to be connected with paraprotein. The aim of this study was to determine the incidence of AvWS in patients with MM, and estimate the role of paraprotein in its occurrence. The study included 40 patients with MM. The plasma level of paraprotein, platelet adhesion on glass pearls, plasma von Willebrand factor antigen concentration, and ristocetin-induced platelet aggregation (RIPA) were measured initially. Absence of RIPA was found in six patients with MM (15%); however, all six of them had normal levels of von Willebrand factor antigen. Paraprotein was isolated from the serum of these patients. Platelet aggregation was measured in six healthy donors before and after addition of the isolated paraprotein. RIPA was significantly decreased in healthy donors in the presence of paraprotein (P<0·001). The same test was repeated with added human immunoglobulins for intravenous use without any change in RIPA. A significant negative correlation between plasma paraprotein level and RIPA was found (P<0·001). These investigations have shown that paraprotein is associated with AvWS in patients with MM.

Association of acquired von Willebrand syndrome with AL amyloidosis

Acquired loss of functional von Willebrand factor (VWF) has been termed the acquired von Willebrand syndrome (AVWS). AVWS is a rare adult-onset bleeding diathesis that is clinically similar to congenital von Willebrand disease (VWD), and occurs with a variety of autoimmune, lymphoproliferative, or myeloproliferative disorders. We have identified four patients with AVWS in association with immunoglobulin light chain (AL) amyloidosis. These patients, lacking any pre-existing or family history of abnormal bleeding, developed cutaneous, mucosal, or gastrointestinal bleeding in the course of their disease without deficiency of clotting factor X or other factors; the activated partial thromboplastin time (aPTT) was prolonged in three out of the four cases. Despite normal VWF antigen levels, VWF ristocetin cofactor activity (VWF:RCo) was low. Electrophoresis patterns of high molecular weight (HMW) VWF multimers were abnormal in two of the four cases. Two of the patients were treated with high-dose intravenous melphalan followed by autologous stem cell transplantation (HDM/SCT) and achieved hematologic remission. In these two patients, the bleeding diathesis improved and the coagulation parameters normalized, confirming a causal relationship between the plasma cell dyscrasia and the AVWS. AVWS should be considered in AL amyloidosis patients with hemorrhagic diatheses and normal clotting factor levels.

Acquired von Willebrand syndrome: features and management

Acquired von Willebrand syndrome (AvWS) is not a well-known bleeding disorder among clinicians and is associated with various underlying diseases. The clinical manifestations are similar to congenital von Willebrand disease. Diagnosis is confirmed mainly by a decrease of ristocetin cofactor activity (vWF:RCo) and/or collagen binding activity (vWF:CBA) and by vWF multimeric analysis, usually with a selective loss of large multimers. Plasma von Willebrand factor propeptide (vWF:AgII) is a good marker of vWF synthesis. Various pathogenic mechanisms have been proposed, including development of autoantibodies to the von Willebrand factor (vWF), adsorption of vWF onto tumor cells or activated platelets, increase of vWF proteolysis, and mechanical destruction of vWF under high shear stress. Treatment of the underlying disorder may resolve AvWS. Desmopressin (DDAVP) is a first-line therapeutic option. Factor VIII/vWF concentrates and high-dose immunoglobulin infusions are reserved for patients unresponsive to DDAVP.

A new ELISA assay for diagnosis of acquired von Willebrand syndrome

The pathophysiology of acquired von Willebrand syndrome (AVWS), a rare bleeding disorder, is not fully understood. Circulating antibodies to Von Willebrand factor (VWF) are found in patients with AVWS associated with lymphoproliferative disorders but these autoantibodies are difficult to detect with routine laboratory tests and neutralisation assays. We have developed a simple enzyme-linked immunosorbent assay (ELISA) to detect serum antibody binding to VWF protein immobilized on polystyrene plates. Ten patients with AVWS were studied, eight of whom also had lymphoproliferative disorders. We found antibodies in eight patients; all of them were positive for IgG and five were also positive for IgM. This simple method appears to be more sensitive than functional assays, which failed to identify two of the patients who were positive with the ELISA. In conjunction with other tests, this ELISA method may be useful for demonstrating the immunological mechanism underlying some cases of AVWS. Such patients would qualify for intravenous immunoglobulin therapy, which can correct the clotting disorder.

Undiagnosed multiple myeloma causing extensive dental bleeding: report of a case and review

A case of multiple myeloma causing profuse bleeding during a minor dental surgical procedure is presented. The value of dental radiography in detection of bone changes associated with an undiagnosed case of multiple myeloma is highlighted. We show that the extensive bleeding during the dental procedure could have been prevented if the panoramic radiograph had been evaluated carefully before initiation of the treatment. In addition, we briefly discuss the etiologic factors responsible for the formation of hemostatic abnormalities in multiple myeloma and the value of imaging methods used in diagnostic assessment of the disease.

Bleeding diathesis in multiple myeloma

Patients with multiple myeloma having a higher titer of serum paraproteins can manifest hemostatic abnormalities. Most of these abnormalities predispose the patient to hemorrhage. Less commonly, thrombotic complications may occur in association with paraprotein disorders. We investigated a 56-year-old female diagnosed with multiple myeloma (type IgG kappa, 59 g/L) whose coagulation profile showed an increase in thrombin time and prothrombin time. To investigate the etiology of the abnormal coagulopathy, further diagnostic studies including coagulation factor assays, platelet aggregation studies, replitase time, mixing studies using pooled normal plasma, and protamine were performed. Mixing studies demonstrated correction of the prothrombin time. Thrombin time was near-corrected but the replitase-time was not corrected by these mixing studies. After chemotherapy, the paraprotein concentration decreased (12g/L) and the coagulation results returned to normal. Patients with multiple myeloma may develop bleeding diathesis secondary to a variety of mechanisms. One such mechanism is direct inhibition of fibrin monomer aggregation due to the paraprotein, resulting in prolongation of the thrombin time and the replitase time. The failure to correct the former by the addition of protamine further augments the direct role of FAB portion of the paraprotein molecule on inhibition of fibrin monomers.

Therapeutic approaches to acquired von Willebrand syndrome

Acquired von Willebrand syndrome (AVWS) is a rare acquired bleeding disorder similar to the congenital von Willebrand disease (VWD) in terms of laboratory findings. Diagnosis of AVWS can be very difficult, with treatment normally taking an empirical form. Although more than 200 cases have been reported since 1968, no retrospective or prospective studies are available on AVWS. Recently, an International Registry on AVWS, gathering data directly from worldwide Departments of Haematology-Oncology and Haemophilia Centres, has been organised by a group working on behalf of the Subcommittee on VWF in the Scientific Standardisation Committee (SSC) of International Society on Thrombosis and Haemostasis (ISTH). Information about an additional 211 AVWS patients is now available, with more detailed data on demography, type of haemorrhage, diagnostic tests for AVWS and management of bleeding episodes. The additional 211 AVWS cases are associated with lymphoproliferative (47%) or myeloproliferative (19%) disorders, cardiovascular diseases, neoplasia (7%) and other miscellaneous diseases (14%). Bleeding episodes of AVWS patients were managed by different compounds including desmopressin (22%), FVIII/VWF concentrates (26%) and high-dose immunoglobulin (10%), plasmapheresis (2%), steroids (5%) and immunosuppressive drugs (20%). Based on complied data, we can conclude that none of the therapeutic approaches proposed are 100% effective in all AVWS cases. Therefore, treatment must be customized for each patient according to the underlying disorder, as well as to the type and the severity of bleeding episode and must be targeted to each specific case.

Acquired von Willebrand syndrome--report of 10 cases and review of the literature

Acquired von Willebrand syndrome (AvWS) is a rare bleeding disorder with clinical and laboratory features closely resembling hereditary von Willebrand disease (vWD), arising in previously haemostatically normal individuals. We present a retrospective review of 10 cases with AvWS diagnosed over 17 years. The severity of the bleeding tendency varied from mild to severe forms. Multimers electrophoresis showed that 8/10 patients had a normal pattern similar to type 1 vWD, 1/10 had a type 2A vWD pattern (with absence of high and intermediate molecular weight multimers) and 1/10 had a type 3 vWD pattern. An inhibitor screen was performed in 6/10 patients and autoantibodies against von Willebrand factor were found in only two cases. The underlying cause/associated conditions were identified in 8/10 patients. Treatment of the bleeding diathesis was successfully achieved with desmopressin or clotting factor concentrates. Resolution of underlying hypothyroidism (in two cases) and multiple myeloma (in one case) led to normalization of the coagulation parameters. The report on this cohort of 10 patients with AvWS illustrates the complexity of AvWS and its multifactorial aetiology. A brief review of the recent literature on AvWS is also presented, with emphasis on the current opinions in pathogenesis and treatment. Acquired von Willebrand syndrome (AvWS) is an acquired bleeding disorder, characterized by a phenotype similar to the inherited von Willebrand disease (vWD), with a prolonged bleeding time and low plasma levels of factor VIII - von Willebrand factor (vWF) measurements. It occurs in patients with no family history of vWD, who present with recent onset of bleeding symptoms. AvWS appears to be associated mainly with lymphoproliferative disorders, immunological conditions and neoplasia. AvWS is a rare condition and it is difficult to conduct prospective studies, therefore it is important to document the experience with such cases. The aim of this paper is first, to report 10 cases of AvWS identified at our Haemophilia Centre during the past 17 years. Second, to present a brief review of the recent literature on AvWS - outlining the salient features, associated disorders, mechanisms of acquisition and the available options of treatment.