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Liang Q, Parker ET, Dean G, Karpen MS, Wu Y, Wang X, Di Paola J, Maier CL, Meeks SL, Lollar P, Sidonio RF, Li R. Nanobody activator improves sensitivity of the von Willebrand factor activity assay to multimer size. J Thromb Haemost 2024; 22:2052-2058. [PMID: 38704122 PMCID: PMC11214880 DOI: 10.1016/j.jtha.2024.04.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 04/15/2024] [Accepted: 04/19/2024] [Indexed: 05/06/2024]
Abstract
BACKGROUND The activity of von Willebrand factor (VWF) in facilitating platelet adhesion and aggregation correlates with its multimer size. Traditional ristocetin-dependent functional assays lack sensitivity to multimer sizes. Recently, nanobodies targeting the autoinhibitory module and activating VWF were identified. OBJECTIVES To develop an assay that can differentiate the platelet-binding activity of VWF multimers. METHODS A novel enzyme-linked immunosorbent assay (nanobody-triggered glycoprotein Ib binding assay [VWF:GPIbNab]) utilizing a VWF-activating nanobody was developed. Recombinant VWF, plasma-derived VWF (pdVWF), and selected gel-filtrated fractions of pdVWF were evaluated for VWF antigen and activity levels. A linear regression model was developed to estimate the specific activity of VWF multimers. RESULTS Of the 3 activating nanobodies tested, 6C11 with the lowest activation effect exhibited the highest sensitivity for high-molecular-weight multimers (HMWMs) of VWF. VWF:GPIbNab utilizing 6C11 (VWF:GPIbNab6C11) produced significantly higher activity/antigen ratios for recombinant VWF (>2.0) and HMWM-enriched pdVWF fractions (>2.0) than for pdVWF (∼1.0) or fractions enriched with shorter multimers (<1.0). The differences were much larger than those produced by VWF:GPIbNab utilizing other nanobodies, VWF:GPIbM, VWF:GPIbR, or VWF:CB assays. Linear regression analysis of 5 pdVWF fractions of various multimer sizes produced an estimated specific activity of 2.7 for HMWMs. The analysis attributed >90% of the VWF activity measured by VWF:GPIbNab6C11 to that of HMWMs, which is significantly higher than all other activity assays tested. CONCLUSION The VWF:GPIbNab6C11 assay exhibits higher sensitivity to HMWMs than ristocetin-based and collagen-binding assays. Future studies examining the application of this assay in clinical settings and any associated therapeutic benefit of doing so are warranted.
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Affiliation(s)
- Qian Liang
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Ernest T Parker
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Gabrielle Dean
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Matthew S Karpen
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Yujia Wu
- Department of Statistics, School of Statistics and Center of Statistical Research, Southwestern University of Finance and Economics, Chengdu, China
| | - Xuefeng Wang
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Jorge Di Paola
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Cheryl L Maier
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Shannon L Meeks
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Pete Lollar
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Robert F Sidonio
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Renhao Li
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia, USA.
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Federici AB. Current Diagnosis of von Willebrand Disease in Italy: 3 Years Following the Release of the International Guidelines. Semin Thromb Hemost 2024. [PMID: 38950597 DOI: 10.1055/s-0044-1787841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/03/2024]
Abstract
The American Society of Hematology-International Society on Thrombosis and Haemostasis-National Hemophilia Foundation-World Federation of Hemophilia 2021 International Guidelines (IGL) on von Willebrand disease (VWD) have pointed out many challenges, mainly in the diagnostic approach of VWD patients. To determine the impact of these IGL on the current clinical and laboratory diagnosis of Italian VWD patients, we have recently conducted a survey among 43 centers affiliated with the Italian Association of Hemophilia Centers (AICE). Directors and colleagues responsible for the management of VWD patients were invited to report in a detailed questionnaire how IGL recommendations about the assessment of the specific activities of von Willebrand Factor (VWF) could be applied at their local sites. Results from such a survey showed that bleeding assessment tools, VWF antigen, and factor VIII procoagulant are currently in use in all centers. The automated assays for platelet-dependent VWF activity with or without ristocetin described in IGL have been used since 2021 in 37/43 (86%) centers. Among other laboratory tests, VWF collagen binding, ristocetin-induced platelet agglutination, multimeric analysis, VWF propeptide, VWF:FVIII binding assay were available in 49, 63, 26, 7, and 28% of AICE, respectively. Analyses of VWF gene defects are available only at 3/43 (7%) centers. Desmopressin (DDAVP) infusion trials at diagnosis, with measurements of VWF activities at 1 and 4 hours post-DDAVP, is currently performed at 38/43 (88%) centers. Based on this information, a simplified clinical diagnosis using a few automated tests before and after DDAVP has been proposed. Such a diagnostic approach will be validated prospectively in a large cohort of Italian VWD patients.
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Affiliation(s)
- Augusto B Federici
- Hematology and Transfusion Medicine, School of Medicine of the University of Milan, L. Sacco University Hospital, Milan, Italy
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3
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Favaloro EJ. 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. Semin Thromb Hemost 2024; 50:43-80. [PMID: 36807283 DOI: 10.1055/s-0043-1763259] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
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.
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Affiliation(s)
- Emmanuel J Favaloro
- Department of Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), Sydney Centres for Thrombosis and Haemostasis, NSW Health Pathology, Westmead Hospital, Westmead, New South Wales, Australia
- School of Dentistry and Medical Sciences, Faculty of Science and Health, Charles Sturt University, Wagga Wagga, New South Wales, Australia
- School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Westmead Hospital, Westmead, New South Wales, Australia
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Favaloro EJ. Evolution of Hemostasis Testing: A Personal Reflection Covering over 40 Years of History. Semin Thromb Hemost 2024; 50:8-25. [PMID: 36731486 DOI: 10.1055/s-0043-1761487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
There is no certainty in change, other than change is certain. As Seminars in Thrombosis and Hemostasis celebrates 50 years of publication, I felt it appropriate to reflect on my own 40-year plus scientific career. My career in the thrombosis and hemostasis field did not start until 1987, but the subsequent 35 years reflected a period of significant change in associated disease diagnostics. I started in the Westmead Hospital "coagulation laboratory" when staff were still performing manual clotting tests, using stopwatches, pipettes, test tubes, and a water bath, which we transported to the hospital outpatient department to run our weekly warfarin clinic. Several hemostasis instruments have come and gone, including the Coag-A-Mate X2, the ACL-300R, the MDA-180, the BCS XP, and several StaR Evolution analyzers. Some instruments remain, including the PFA-100, PFA-200, the AggRAM, the CS-5100, an AcuStar, a Hydrasys gel system, and two ACL-TOP 750s. We still have a water bath, but this is primarily used to defrost frozen samples, and manual clotting tests are only used to teach visiting medical students. We have migrated across several methodologies in the 45-year history of the local laboratory. Laurel gel rockets, used for several assays in the 1980s, were replaced with enzyme-linked immunosorbent assay assays and most assays were eventually placed on automated instruments. Radio-isotopic assays, used in the 1980s, were replaced by an alternate safer method or else abandoned. Test numbers have increased markedly over time. The approximately 31,000 hemostasis assays performed at the Westmead-based laboratory in 1983 had become approximately 200,000 in 2022, a sixfold increase. Some 90,000 prothrombin times and activated partial thromboplastic times are now performed at this laboratory per year. Thrombophilia assays were added to the test repertoires over time, as were the tests to measure several anticoagulant drugs, most recently the direct oral anticoagulants. I hope my personal history, reflecting on the changes in hemostasis testing over my career to date in the field, is found to be of interest to the readership, and I hope they forgive any inaccuracies I have introduced in this reflection of the past.
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Affiliation(s)
- Emmanuel J Favaloro
- Department of Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), Sydney Centres for Thrombosis and Haemostasis, NSW Health Pathology, Westmead Hospital, Westmead, NSW Australia
- School of Dentistry and Medical Sciences, Faculty of Science and Health, Charles Sturt University, Wagga Wagga, New South Wales, Australia
- School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Westmead Hospital, Westmead, New South Wales, Australia
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Favaloro EJ, Pasalic L. Laboratory Diagnosis of von Willebrand Disease (VWD): Geographical Perspectives. Semin Thromb Hemost 2022; 48:750-766. [PMID: 36055264 DOI: 10.1055/s-0042-1754331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
von Willebrand disease (VWD) is reportedly the most common inherited bleeding disorder, and can also arise as an acquired (von Willebrand) syndrome (AVWS). The hemostasis laboratory plays a key role in the diagnosis or exclusion of VWD/AVWS, which may otherwise be suspected due to the patient's clinical (bleeding) history. VWD/AVWS arise from deficiency and/or defects in the adhesive plasma protein, von Willebrand factor (VWF). VWF undertakes various roles within hemostasis, but principally acts within primary hemostasis to anchor platelets to sites of vascular damage, thereby facilitating thrombus formation to arrest bleeding. The diagnosis or exclusion of VWD/AVWS requires laboratory testing for both VWF level and activity, with the latter potentially comprising several of a potential plethora of different assays. Complete diagnosis of VWD also requires the differentiation of VWD type, with six types comprising the current classification (i.e., qualitative [types 2A, 2B, 2M, 2N VWD] vs. quantitative [types 1 and 3 VWD] deficiency/defects). Although appropriate diagnosis and type classification hold important therapeutic consequences, these remain problematic and sometimes elusive for some laboratories to achieve. This report reviews the laboratory aided diagnosis or exclusion of VWD from a geographic perspective, and focuses on the disparities of approaches and methods in different regions of the world. This is primarily done from the perspective of data available from published reports related to external quality assessment (or proficiency testing) from different geographic localities. Moreover, differences in approaches between laboratories may arise due to differential adherence of particular guidelines, as well as regulatory aspects and predominance of local manufacturers and suppliers.
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Affiliation(s)
- Emmanuel J Favaloro
- Department of Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead, North South Wales, Australia.,Sydney Centres for Thrombosis and Haemostasis, Westmead, North South Wales, Australia.,Faculty of Science and Health, Charles Sturt University, Wagga Wagga, North South Wales, Australia
| | - Leonardo Pasalic
- Department of Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead, North South Wales, Australia.,Sydney Centres for Thrombosis and Haemostasis, Westmead, North South Wales, Australia.,Westmead Clinical School, University of Sydney, Westmead, North South Wales, Australia
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6
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Woods AI, Paiva J, Primrose DM, Blanco AN, Sánchez-Luceros A. Type 2A and 2M von Willebrand Disease: Differences in Phenotypic Parameters According to the Affected Domain by Disease-Causing Variants and Assessment of Pathophysiological Mechanisms. Semin Thromb Hemost 2021; 47:862-874. [PMID: 34130347 DOI: 10.1055/s-0041-1726097] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Type 2A and 2M von Willebrand disease (VWD) broadly show similar phenotypic parameters, but involve different pathophysiological mechanisms. This report presents the clinical and laboratory profiles of type 2A and type 2M patients genotypically diagnosed at one large center. Higher bleeding score values and a higher incidence of major bleeding episodes were observed in type 2A compared with type 2M, potentially reflective of the absence of large and intermediate von Willebrand factor (VWF) multimers in 2A. In type 2A, most of disease-causing variants (DCVs) appeared to be responsible for increased VWF clearance and DCV clustered in the VWF-A1 domain resulted in more severe clinical profiles. In type 2M, DCV in the VWF-A1 domain showed different laboratory patterns, related to either reduced synthesis or shortened VWF survival, and DCV in the VWF-A2 domain showed patterns related mainly to shortened survival. VWF-type 1 collagen binding/Ag (C1B/Ag) showed different patterns according to DCV location: in type 2A VWD, C1B/Ag was much lower when DCVs were located in the VWF-A2 domain. In type 2M with DCV in the VWF-A1domain, C1B/Ag was normal, but with DCV in the VWF-A2 domain, C1B/Ag was low. The higher frequency of major bleeding in VWD 2M patients with DCV in the VWF-A2 domain than that with DCV in the VWF-A1 domain could be a summative effect of abnormal C1B/Ag, on top of the reduced VWF-GPIb binding. In silico modeling suggests that DCV impairing the VWF-A2 domain somehow modulates collagen binding to the VWF-A3 domain. Concomitant normal FVIII:C/Ag and VWFpp/Ag, mainly in type 2M VWD, suggest that other nonidentified pathophysiological mechanisms, neither related to synthesis/retention nor survival of VWF, would be responsible for the presenting phenotype.
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Affiliation(s)
- Adriana Inés Woods
- Laboratorio de Hemostasia y Trombosis, IMEX-CONICET-Academia Nacional de Medicina de Buenos Aires. CABA, Argentina
| | - Juvenal Paiva
- Departamento de Hemostasia y Trombosis, Instituto de Investigaciones Hematológicas, Academia Nacional de Medicina de Buenos Aires. CABA, Argentina
| | - Débora Marina Primrose
- Química de los Alimentos, Facultad de Agronomía y Ciencias Agroalimentarias, Universidad de Morón. Buenos Aires, Argentina
| | - Alicia Noemí Blanco
- Departamento de Hemostasia y Trombosis, Instituto de Investigaciones Hematológicas, Academia Nacional de Medicina de Buenos Aires. CABA, Argentina
| | - Analía Sánchez-Luceros
- Laboratorio de Hemostasia y Trombosis, IMEX-CONICET-Academia Nacional de Medicina de Buenos Aires. CABA, Argentina.,Departamento de Hemostasia y Trombosis, Instituto de Investigaciones Hematológicas, Academia Nacional de Medicina de Buenos Aires. CABA, Argentina
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7
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von Willebrand factor binding to myosin assists in coagulation. Blood Adv 2021; 4:174-180. [PMID: 31935285 DOI: 10.1182/bloodadvances.2019000533] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 12/02/2019] [Indexed: 12/18/2022] Open
Abstract
von Willebrand factor (VWF) binds to platelets and collagen as a means of facilitating coagulation at sites of injury. Recent evidence has shown that myosin can serve as a surface for thrombin generation and binds to activated factor V and factor X. We studied whether VWF can also bind myosin as a means of bringing factor VIII (FVIII) to sites of clot formation. A myosin-binding assay was developed using skeletal muscle myosin to measure VWF binding, and plasma-derived and recombinant VWF containing molecular disruptions at key VWF sites were tested. Competition assays were performed using anti-VWF antibodies. FVIII binding to myosin was measured using a chromogenic FVIII substrate. Thrombin generation was measured using a fluorogenic substrate with and without myosin. Wild-type recombinant VWF and human plasma VWF from healthy controls bound myosin, whereas plasma lacking VWF exhibited no detectable myosin binding. Binding was multimer dependent and blocked by anti-VWF A1 domain antibodies or A1 domain VWF variants. The specific residues involved in myosin binding were similar, but not identical, to those required for collagen IV binding. FVIII did not bind myosin directly, but FVIII activity was detected when VWF and FVIII were bound to myosin. Myosin enhanced thrombin generation in platelet-poor plasma, although no difference was detected with the addition of myosin to platelet-rich plasma. Myosin may help to facilitate delivery of FVIII to sites of injury and indirectly accelerate thrombin generation by providing a surface for VWF binding in the setting of trauma and myosin exposure.
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Sweeney JM, Barouqa M, Krause GJ, Gonzalez-Lugo JD, Rahman S, Gil MR. Low ADAMTS13 Activity Correlates with Increased Mortality in COVID-19 Patients. TH OPEN 2021; 5:e89-e103. [PMID: 33709050 PMCID: PMC7943318 DOI: 10.1055/s-0041-1723784] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 12/29/2020] [Indexed: 01/08/2023] Open
Abstract
The causes of coagulopathy associated with coronavirus disease 2019 (COVID-19) are poorly understood. We aimed to investigate the relationship between von Willebrand factor (VWF) biomarkers, intravascular hemolysis, coagulation, and organ damage in COVID-19 patients and study their association with disease severity and mortality. We conducted a retrospective study of 181 hospitalized COVID-19 patients randomly selected with balanced distribution of survivors and nonsurvivors. Patients who died had significantly lower ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) activity, significantly elevated lactate dehydrogenase levels, significantly increased shistocyte/RBC fragment counts, and significantly elevated VWF antigen and activity levels compared with patients discharged alive. These biomarkers correlate with markedly elevated D-dimers. Additionally, only 30% of patients who had an ADAMTS13 activity level of less than 43% on admission survived, yet 60% of patients survived who had an ADAMTS13 activity level of greater than 43% on admission. In conclusion, COVID-19 may present with low ADAMTS13 activity in a subset of hospitalized patients. Presence of schistocytes/RBC fragment and elevated D-dimer on admission may warrant a work-up for ADAMTS13 activity and VWF antigen and activity levels. These findings indicate the need for future investigation to study the relationship between endothelial and coagulation activation and the efficacy of treatments aimed at prevention and/or amelioration of microangiopathy in COVID-19.
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Affiliation(s)
- Joseph M Sweeney
- Department Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York, United States
| | - Mohammad Barouqa
- Department of Pathology Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, United States
| | - Gregory J Krause
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, New York, United States.,Institute of Aging Studies, Albert Einstein College of Medicine, Bronx, New York, United States
| | - Jesus D Gonzalez-Lugo
- Division of Hematology, Department of Medical Oncology, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York, United States
| | - Shafia Rahman
- Division of Hematology, Department of Medical Oncology, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York, United States
| | - Morayma Reyes Gil
- Department of Pathology Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, United States
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9
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Ranger A, Gaspar M, Elkhatteb A, Jackson T, Fox S, Aw TC, Vipond L, Cotterill J, Ghori A, Laffan M, Arachchillage DRJ. The heparin-von Willebrand factor interaction and conventional tests of haemostasis - the challenges in predicting bleeding in cardiopulmonary bypass. Br J Haematol 2020; 192:1073-1081. [PMID: 33278841 DOI: 10.1111/bjh.17263] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 11/13/2020] [Indexed: 01/04/2023]
Abstract
Bleeding is a significant complication of cardiopulmonary bypass (CPB), despite routine anticoagulation monitoring. This is likely to be multifactorial. In this prospective, single-centre cohort study of 30 patients undergoing CPB surgery, our aim was to characterise the changes in von Willebrand factor (VWF) function, platelet interaction and the global coagulation changes during and after CPB surgery and to determine whether bleeding can be predicted. Samples were taken at six time points before, during and after CPB surgery. We observed a significant rise in VWF antigen (VWF:Ag) throughout surgery, which continued postoperatively. The absolute VWF collagen-binding assays (VWF:CB) and VWF ristocetin cofactor (VWF:RCo) rose significantly but the VWF:CB/VWF:Ag and VWF:Ag/VWF:RCo fell significantly (P = 0·0015 and P = 0·0143), suggesting loss of large multimers. We detected a non-significant trend to loss of VWF:RCo after heparinisation and a significant recovery after protamine reversal which could reflect a direct heparin effect. There was a significant increase in the R and K times with a fall in alpha angle and maximum amplitude after heparin administration, using heparinase-thromboelastography (TEG). The parameters both significantly improved following protamine (P = 0·007 and P = 0·0054). The activated clotting time (ACT) and heparin anti-Xa level correlated poorly; neither predicted clinically significant bleeding. None of these parameters had a relationship with intraoperative blood loss or requirement for blood product replacement.
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Affiliation(s)
- Amita Ranger
- Department of Immunology and Inflammation, Imperial College London, London, UK
| | - Mihaela Gaspar
- Department of Haematology, Royal Brompton & Harefield NHS Foundation Trust, London, UK
| | - Amira Elkhatteb
- Department of Anaesthesia, Royal Brompton & Harefield NHS Foundation Trust, London, UK
| | - Tim Jackson
- Department of Perfusion, Royal Brompton & Harefield NHS Foundation Trust, London, UK
| | - Steve Fox
- Department of Haematology, Royal Brompton & Harefield NHS Foundation Trust, London, UK
| | - T C Aw
- Department of Anaesthesia, Royal Brompton & Harefield NHS Foundation Trust, London, UK
| | - Lisa Vipond
- Department of Haematology, Royal Brompton & Harefield NHS Foundation Trust, London, UK
| | - Judy Cotterill
- Department of Anaesthesia, Royal Brompton & Harefield NHS Foundation Trust, London, UK
| | - Arshad Ghori
- Department of Anaesthesia, Royal Brompton & Harefield NHS Foundation Trust, London, UK
| | - Mike Laffan
- Department of Immunology and Inflammation, Imperial College London, London, UK.,Department of Haematology, Imperial College Healthcare NHS Trust, London, UK
| | - Deepa R J Arachchillage
- Department of Immunology and Inflammation, Imperial College London, London, UK.,Department of Haematology, Royal Brompton & Harefield NHS Foundation Trust, London, UK.,Department of Haematology, Imperial College Healthcare NHS Trust, London, UK
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10
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Abstract
von Willebrand factor (VWF) represents a large and complex adhesive plasma protein whose main function is to provide a bridge between blood platelets and damaged endothelium, and thus facilitate primary hemostasis. VWF also binds to FVIII, preventing early proteolysis, and delivers this cargo to sites of vascular injury, thereby promoting clot formation and secondary hemostasis. An absence, deficiency, or defect in VWF can lead to a bleeding diathesis called von Willebrand disease (VWD), considered the most common inherited bleeding disorder. Contemporary laboratory assays used in VWD diagnosis/exclusion comprise a myriad of assays that identify the quantity (level) of VWF, as well as the multitude of VWF activities. These may use the following test abbreviations: VWF:Ag, VWF:RCo, VWF:CB, VWF:GPIbR, VWF:GPIbM, VWF:FVIIB, VWF:Ab. The current review explains what these assays are, as well as their place in VWD diagnostics.
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Affiliation(s)
- Emmanuel J Favaloro
- Department of Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead NSW, Australia.,Sydney Centres for Thrombosis and Haemostasis, Westmead Hospital, Westmead NSW, Australia.,School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia
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11
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Sharma R, Haberichter SL. New advances in the diagnosis of von Willebrand disease. HEMATOLOGY. AMERICAN SOCIETY OF HEMATOLOGY. EDUCATION PROGRAM 2019; 2019:596-600. [PMID: 31808831 PMCID: PMC6913428 DOI: 10.1182/hematology.2019000064] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
von Willebrand disease (VWD) is the most common autosomal inherited bleeding disorder, with an estimated prevalence of 1 in 1000 individuals. VWD is classified into quantitative and qualitative forms. Diagnosis of VWD is complex and requires (1) a personal history of bleeding symptoms, (2) family history of bleeding or VWD, and (3) confirmatory laboratory testing. There are certain bleeding assessment tools to objectively measure bleeding symptoms in patients that have been shown to correlate with the diagnosis as well as the severity of VWD. Laboratory diagnosis requires at least initially a measurement of von Willebrand factor (VWF) antigen levels, VWF platelet binding activity (VWF:RCo, VWF:GPIbM, and VWF:GPIbR), and factor VIII (FVIII) activity. Additional testing to confirm the specific subtype may include VWF collagen binding activity, low-dose ristocetin VWF-platelet binding, FVIII-VWF binding, VWF multimer analysis, and VWF propeptide antigen. Recent advances have been made regarding some of these assays. Molecular testing in VWD is not found to be useful in "low VWF" or most type 1 VWD cases but may be informative in patients with severe type 1 VWD, type 1C VWD, type 2 VWD, or type 3 VWD for accurate diagnosis, genetic counseling, and appropriate treatment. The diagnostic algorithm for VWD is complex, but advances continue to be made in improving VWF functional assays and diagnostic pathways.
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Affiliation(s)
- Ruchika Sharma
- Diagnostic Laboratories and Blood Research Institute, Versiti, Milwaukee, WI
- Pediatric Hematology/Oncology, Medical College of Wisconsin, Milwaukee, WI; and
- Children's Research Institute, Children's Hospital of Wisconsin, Milwaukee, WI
| | - Sandra L Haberichter
- Diagnostic Laboratories and Blood Research Institute, Versiti, Milwaukee, WI
- Pediatric Hematology/Oncology, Medical College of Wisconsin, Milwaukee, WI; and
- Children's Research Institute, Children's Hospital of Wisconsin, Milwaukee, WI
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12
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Higgins RA, Goodwin AJ. Automated assays for von Willebrand factor activity. Am J Hematol 2019; 94:496-503. [PMID: 30592326 DOI: 10.1002/ajh.25393] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 12/18/2018] [Accepted: 12/21/2018] [Indexed: 12/30/2022]
Abstract
von Willebrand factor (VWF) ristocetin cofactor activity (VWF:RCo) by platelet aggregometry has been considered the gold standard for evaluating the ability of VWF to bind platelets for over 40 years. Many automated systems no longer require platelets and rather rely on agglutination of latex particles. Automated methods of measuring VWF activity have improved performance characteristics and are performed on the same coagulation instruments used for routine testing via immunoturbidimetric methodology. Alternatively, a newer chemiluminescence assay system for measuring VWF activity demonstrates excellent performance characteristics. As these methods are becoming widely used, it is important to assess their performance in diagnosing and monitoring different types of von Willebrand disease. We review the automated methodologies and the published performance of these VWF assays. Advantages and limitations of these automated methods are discussed.
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Affiliation(s)
- Russell A. Higgins
- Department of Pathology and Laboratory Medicine University of Texas Health Science Center San Antonio San Antonio Texas
| | - Andrew J. Goodwin
- Department of Pathology and Laboratory Medicine Larner College of Medicine, University of Vermont Burlington Vermont
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13
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Favaloro EJ. Rare forms of von Willebrand disease. ANNALS OF TRANSLATIONAL MEDICINE 2018; 6:345. [PMID: 30306084 PMCID: PMC6174185 DOI: 10.21037/atm.2018.09.10] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 09/06/2018] [Indexed: 12/27/2022]
Abstract
von Willebrand disease (VWD) arises from deficiency and/or defect(s) of plasma von Willebrand factor (VWF). In turn, plasma VWF is an adhesive protein which primarily functions by anchoring platelets to regions of vascular injury, thereby assisting prevention of bleeding. There is a proportional reduction also in Factor VIII, due to the absence of the stabilizing and anti-proteolytic effect that VWF normally exerts. VWD is reportedly the most common inherited bleeding disorder and can be classified into quantitative and qualitative defects, with type 1 and 3 VWD respectively identifying partial and total quantitative deficiency of VWF, and type 2 VWD identifying qualitative defects of VWF. The relative incidence of each subtype of VWD differs according to the locality and the ability of clinicians and laboratories to correctly diagnose and classify cases. In general, type 1 VWD is considered the most common type of VWD, whereas types 2 and 3 represent rarer forms. However, in developing countries, and partly because of consanguinity, type 3 VWD is over-represented. This review primarily focuses on the rarer forms of VWD, which typically comprise types 2 (A, B, M and N) and 3 VWD. The review also mentions type 1 VWD, largely for completeness and comparability, and since purportedly "severe" type 1 VWD, albeit not a formally recognized subtype of type 1 VWD, would represent a relatively "rare" form of VWD.
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Affiliation(s)
- Emmanuel J. Favaloro
- Laboratory Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead, NSW, Australia
- Sydney Centres for Thrombosis and Haemostasis, Westmead, NSW, Australia
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14
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Palyu E, Harsfalvi J, Tornai T, Papp M, Udvardy M, Szekeres-Csiki K, Pataki L, Vanhoorelbeke K, Feys HB, Deckmyn H, Tornai I. Major Changes of von Willebrand Factor Multimer Distribution in Cirrhotic Patients with Stable Disease or Acute Decompensation. Thromb Haemost 2018; 118:1397-1408. [PMID: 29972862 PMCID: PMC6202934 DOI: 10.1055/s-0038-1661393] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Background
There is an unstable balance between pro- and anti-haemostatic processes in patients with cirrhosis. We hypothesized, that in patients with acute decompensation (AD) the major alterations of von Willebrand factor (VWF) could contribute to the pro-thrombotic situation as compared to patients with stable (ST) cirrhosis.
Patients and Methods
We analysed different parameters of VWF, including detailed multimer distribution by densitometry and platelet adhesion, together with
ad
isintegrin-like
a
nd
m
etalloproteinase with
t
hrombo
s
pondin type-1 motifs
13
(ADAMTS13) activity and antigen and C-reactive protein (CRP) levels in patients with ST cirrhosis (
n
= 99), with AD (
n
= 54) and controls (
n
= 92).
Results
VWF antigen, ristocetin co-factor as well as collagen-binding activities were elevated in both cirrhotic groups in a stepwise manner. There was a decrease in high and an increase in low molecular weight multimer ratios in the majority of ST cirrhosis. However, in 24 out of 54 AD patients, ultra-large VWF multimers (ultra-large molecular weight multimers [ULMWM]) were found. ADAMTS13 activity in ST and AD patients without ULMWM was similar to controls (median [interquartile range; IQR]%: 98 [67–132] and 91 [60–110] vs. 106 [88–117], respectively). The presence of ULMWM in AD patients was associated with low ADAMTS13 activity [33 (24–49)%] and high CRP level [23 (7.1–83.6) mg/L]. Adhesion of normal platelets showed a stepwise increase in the presence of cirrhotic plasmas, reaching the highest level in AD patients with ULMWM.
Conclusion
Characteristic changes of VWF parameters are seen in ST cirrhosis. In AD patients, highly increased VWF and reduced ADAMTS13 activity could be found, along with the presence of ULMWM, which are possible markers and contributors of the disease progression.
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Affiliation(s)
- Eszter Palyu
- Division of Gastroenterology, Department of Internal Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Jolan Harsfalvi
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary
| | - Tamas Tornai
- Division of Gastroenterology, Department of Internal Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Maria Papp
- Division of Gastroenterology, Department of Internal Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Miklos Udvardy
- Department of Laboratory Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Katalin Szekeres-Csiki
- Department of Laboratory Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Lajos Pataki
- Department of Laboratory Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Karen Vanhoorelbeke
- Laboratory for Thrombosis Research, IRF Life Science, KU Leuven Kulak, Kortrijk, Belgium
| | - Hendrik B Feys
- Transfusion Research Center, Belgian Red Cross-Flanders, Ghent, Belgium.,Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Hans Deckmyn
- Laboratory for Thrombosis Research, IRF Life Science, KU Leuven Kulak, Kortrijk, Belgium
| | - Istvan Tornai
- Division of Gastroenterology, Department of Internal Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
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15
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Crist RA, Heikal NM, Rodgers GM, Grenache DG, Smock KJ. Evaluation of a new commercial method for von Willebrand factor multimeric analysis. Int J Lab Hematol 2018; 40:586-591. [PMID: 29920949 DOI: 10.1111/ijlh.12869] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 05/08/2018] [Indexed: 12/12/2022]
Abstract
INTRODUCTION Evaluation of von Willebrand factor (VWF) multimeric distribution is useful for subclassification of von Willebrand disease (VWD). Multimer analysis has historically been a manual, labor-intensive laboratory-developed test. The first commercial method for multimeric analysis was recently developed that utilizes a single instrument for gel electrophoresis, staining, and densitometry. The current study was undertaken to evaluate the performance characteristics of the new commercial method. METHODS Studies performed with the commercial method included evaluation of accuracy (method comparison), reference intervals (establishment of normal migration patterns in normal donor specimens), precision (multimer pattern reproducibility), and analytical sensitivity. RESULTS In the method comparison studies, concordant interpretations were obtained in 19 of 24 comparisons, including normal and abnormal specimens. The 5 specimens with discordant interpretations all involved slight differences and none were considered clinically significant. Thirty-eight normal donor specimens demonstrated normal multimer patterns. Multimer pattern reproducibility was demonstrated in normal and abnormal controls tested on each gel. In the sensitivity studies, adequate visualization of multimers was determined to require VWF protein concentrations of approximately 5%-10% of normal. CONCLUSION The commercial multimer method is a streamlined test that demonstrates comparable performance characteristics to our current laboratory-developed method and that provides the advantage of both electrophoresis gels and densitometry scans to aid interpretation.
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Affiliation(s)
- R A Crist
- ARUP Laboratories Institute for Clinical and Experimental Pathology, University of Utah, Salt Lake City, UT, USA
| | - N M Heikal
- ARUP Laboratories Institute for Clinical and Experimental Pathology, University of Utah, Salt Lake City, UT, USA.,Department of Pathology, University of Utah, Salt Lake City, UT, USA
| | - G M Rodgers
- ARUP Laboratories Institute for Clinical and Experimental Pathology, University of Utah, Salt Lake City, UT, USA.,Department of Pathology, University of Utah, Salt Lake City, UT, USA.,Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
| | - D G Grenache
- ARUP Laboratories Institute for Clinical and Experimental Pathology, University of Utah, Salt Lake City, UT, USA.,Department of Pathology, University of Utah, Salt Lake City, UT, USA
| | - K J Smock
- ARUP Laboratories Institute for Clinical and Experimental Pathology, University of Utah, Salt Lake City, UT, USA.,Department of Pathology, University of Utah, Salt Lake City, UT, USA
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16
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Favaloro EJ, Bonar R, Hollestelle MJ, Jennings I, Mohammed S, Meijer P, Woods T, Meiring M. Differential sensitivity of von Willebrand factor activity assays to reduced VWF molecular weight forms: A large international cross-laboratory study. Thromb Res 2018; 166:96-105. [DOI: 10.1016/j.thromres.2018.04.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 02/22/2018] [Accepted: 04/16/2018] [Indexed: 12/17/2022]
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17
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Favaloro EJ, Jennings I, Olson J, Van Cott EM, Bonar R, Gosselin R, Meijer P. Towards harmonization of external quality assessment/proficiency testing in hemostasis. ACTA ACUST UNITED AC 2018; 57:115-126. [DOI: 10.1515/cclm-2018-0077] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Accepted: 02/08/2018] [Indexed: 11/15/2022]
Abstract
Abstract
Quality in diagnostic testing represents a key target of laboratory medicine, for which an assurance around the quality of testing is expected from all involved in the process. Laboratories attempt to assure the quality of their testing by various processes, but especially by performance of internal quality control and external quality assessment (EQA). This is especially true for tests of hemostasis and coagulation. EQA in general provides information on test accuracy and on evaluation of long-term laboratory performance. EQA providers support laboratory performance by various means, including distribution of material for testing of analytes (“proficiency testing”), educational support through expert advice, distribution of publications or case series. Participation in EQA is often a laboratory accreditation requirement. This review aims to identify some of the strengths and weaknesses of EQA, and targets attempts towards harmonization of EQA practice, in order to achieve the best outcome for participant laboratories and, thus, for patients and their clinical care providers.
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Affiliation(s)
- Emmanuel J. Favaloro
- Department of Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital , Westmead, NSW 2145 , Australia
- Sydney Centres for Thrombosis and Haemostasis , Westmead, NSW , Australia
| | | | - John Olson
- Department of Pathology and Laboratory Medicine , University of Texas Health Science Center , San Antonio, TX , USA
| | | | - Roslyn Bonar
- RCPAQAP Haematology , St Leonards, NSW , Australia
| | - Robert Gosselin
- Davis Health System, Hemophilia Treatment Center, University of California , Sacramento, CA , USA
| | - Piet Meijer
- ECAT Foundation , Voorschoten , The Netherlands
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18
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Favaloro E, Koutts J, Mina A. A novel flow cytometry single tube bead assay for quantitation of von Willebrand factor antigen and collagen-binding. Thromb Haemost 2017; 108:999-1005. [DOI: 10.1160/th12-05-0294] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2012] [Accepted: 08/11/2012] [Indexed: 11/05/2022]
Abstract
SummaryDeficiency of or defects in the plasma protein von Willebrand factor (VWF) lead to bleeding and von Willebrand disease (VWD), which may be congenital or acquired. VWD is considered the most common inherited bleeding disorder and laboratory testing for VWF level and activity is critical for appropriate diagnosis and management. We have designed and established a novel Flow Cytometry (FC) based method for measuring VWF antigen (VWF:Ag) and collagen binding (VWF:CB), together in the same tube and at the same time. The results of the novel FC method have been compared against existing reference methods using a range of normal and pathological material. Methods correlated well (VWF:Ag, r=0.866; VWF:CB, r=0.888) and generally permitted similar discrimination of quantitative versus qualitative VWD types (e.g. type 1 vs type 2A or 2B VWD). The novel procedure is expected to permit future streamlined performance of VWD screening, either using stand-alone FC systems or potentially incorporated into FC-capable automated blood cell and particle counters to allow for improved, automated and faster identification or exclusion of VWD.
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19
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Favaloro EJ, Oliver S, Mohammed S, Ahuja M, Grzechnik E, Azimulla S, McDonald J, Lima-Oliveira G, Lippi G. Potential misdiagnosis of von Willebrand disease and haemophilia caused by ineffective mixing of thawed plasma. Haemophilia 2017; 23:e436-e443. [DOI: 10.1111/hae.13305] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/12/2017] [Indexed: 12/15/2022]
Affiliation(s)
- E. J. Favaloro
- Department of Haematology; Institute of Clinical Pathology and Medical Research; NSW Health Pathology; Westmead Hospital; Westmead NSW Australia
- Sydney Centres for Thrombosis and Haemostasis; Westmead Hospital; Westmead NSW Australia
| | - S. Oliver
- Department of Haematology; Institute of Clinical Pathology and Medical Research; NSW Health Pathology; Westmead Hospital; Westmead NSW Australia
| | - S. Mohammed
- Department of Haematology; Institute of Clinical Pathology and Medical Research; NSW Health Pathology; Westmead Hospital; Westmead NSW Australia
| | - M. Ahuja
- Department of Haematology; Institute of Clinical Pathology and Medical Research; NSW Health Pathology; Westmead Hospital; Westmead NSW Australia
| | - E. Grzechnik
- Department of Haematology; Institute of Clinical Pathology and Medical Research; NSW Health Pathology; Westmead Hospital; Westmead NSW Australia
| | - S. Azimulla
- Department of Haematology; Institute of Clinical Pathology and Medical Research; NSW Health Pathology; Westmead Hospital; Westmead NSW Australia
| | - J. McDonald
- Department of Haematology; Institute of Clinical Pathology and Medical Research; NSW Health Pathology; Westmead Hospital; Westmead NSW Australia
| | - G. Lima-Oliveira
- Section of Clinical Biochemistry; University of Verona; Verona Italy
| | - G. Lippi
- Section of Clinical Biochemistry; University of Verona; Verona Italy
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20
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Ettel M, Nardi MA, McVoy L. Validation of automated latex von Willebrand factor activity assay in a new prospective study including post-treatment patient samples. Int J Lab Hematol 2017; 39:286-292. [PMID: 28120508 DOI: 10.1111/ijlh.12622] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 12/06/2016] [Indexed: 12/18/2022]
Abstract
INTRODUCTION Von Willebrand disease (VWD) is the most prevalent inherited bleeding disorder. Diagnosis requires measurement of VWF-platelet binding function, for which VWF ristocetin cofactor activity (VWF:RCo) is the reference method. Recently, an automated latex particle-enhanced immunoturbidimetric von Willebrand factor activity assay (VWF:Ab) has been validated showing superior characteristics. We further validate VWF:Ab in a prospective study including post-treatment patient samples. METHODS A total of 1151 samples were collected from patients tested for VWD, including 119 samples from patients treated with desmopressin or VWF replacement product. All samples were tested for VWF:Ab and VWF:RCo, and the methods were compared using linear regression. Imprecision, linearity and lower detection limit were determined for both assays. RESULTS VWF:Ab showed improved precision compared to VWF:RCo. Linear regression of VWF:Ab and VWF:RCo across all samples exhibited good agreement (R2 = 0.89) with statistical significance (P < 0.001) and bias of -8.7. Concordance was high in classifying samples as normal or abnormal. Analysis of treated samples showed excellent agreement (R2 = 0.91) with statistical significance (P < 0.001) and bias of -4.3. CONCLUSIONS Our analysis validates the VWF:Ab assay in a prospective study of a large cohort of patient samples and extends these results to post-treatment patient samples.
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Affiliation(s)
- M Ettel
- Department of Pathology, New York University School of Medicine, New York, NY, USA
| | - M A Nardi
- Department of Pathology, New York University School of Medicine, New York, NY, USA.,Department of Pediatrics, New York University School of Medicine, New York, NY, USA
| | - L McVoy
- Department of Pathology, New York University School of Medicine, New York, NY, USA
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21
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Oliver S, Lau KKE, Chapman K, Favaloro EJ. Laboratory Testing for Von Willebrand Factor Multimers. Methods Mol Biol 2017; 1646:495-511. [PMID: 28804850 DOI: 10.1007/978-1-4939-7196-1_36] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Von Willebrand disease (VWD) is reportedly the most common inherited bleeding disorder and can also arise as an acquired syndrome (AVWS). These disorders develop due to defects and/or deficiency of the plasma protein von Willebrand factor (VWF). Laboratory testing for the VWF-related disorders requires assessment of both VWF level and VWF activity, the latter requiring multiple assays because of the many functions carried out by VWF to help prevent bleeding. As an additional step, an evaluation of VWF structural features by multimer analysis is useful in selective investigations. The current paper therefore describes a protocol for assessment of VWF multimers by gel electrophoresis, thus enabling identification of protein bands that represent differently sized multimers. The sample protocol described in this chapter is the methodology developed by Sebia.
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Affiliation(s)
- Susan Oliver
- Department of Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead, NSW, 2145, Australia
| | - Kun Kan Edwin Lau
- Department of Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead, NSW, 2145, Australia
| | - Kent Chapman
- Department of Haematology, Pathology North, John Hunter Hospital, NSW Health Pathology, New Lambton Hts, NSW, Australia
| | - Emmanuel J Favaloro
- Haematology Department, Sydney Centres for Thrombosis and Haemostasis, Institute of Clinical Pathology and Medical Research (ICPMR), Westmead Hospital, NSW Health Pathology, Westmead, NSW, 2145, Australia.
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22
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Sánchez-Luceros A, Woods AI, Bermejo E, Shukla S, Acharya S, Lavin M, Rydz N, Othman M. PT-VWD posing diagnostic and therapeutic challenges – small case series. Platelets 2016; 28:484-490. [DOI: 10.1080/09537104.2016.1237625] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Analía Sánchez-Luceros
- Hematological Research Institute, National Academy of Medicine, Buenos Aires, Argentina
- Institute of Experimental Medicine, CONICET-National Academy of Medicine, Buenos Aires, Argentina
| | - Adriana I. Woods
- Institute of Experimental Medicine, CONICET-National Academy of Medicine, Buenos Aires, Argentina
| | - Emilse Bermejo
- Hematological Research Institute, National Academy of Medicine, Buenos Aires, Argentina
| | - Shilpa Shukla
- Hemophilia Treatment Center, North Shore Long Island Jewish Health System, Cohen Children’s Medical Center of New York, North Hyde Park, NY, USA
| | - Suchitra Acharya
- Hemophilia Treatment Center, North Shore Long Island Jewish Health System, Cohen Children’s Medical Center of New York, North Hyde Park, NY, USA
| | - Michelle Lavin
- National Centre for Hereditary Coagulation Disorders, St James’s Hospital, Dublin, Ireland
| | - Natalia Rydz
- Division of Hematology and Hematologic Malignancies, University of Calgary, Calgary, Canada
| | - Maha Othman
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Canada
- School of Baccalaureate Nursing, St Lawrence College, Kingston, Canada
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23
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Favaloro EJ, Pasalic L, Curnow J. Laboratory tests used to help diagnose von Willebrand disease: an update. Pathology 2016; 48:303-18. [DOI: 10.1016/j.pathol.2016.03.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 03/15/2016] [Accepted: 03/20/2016] [Indexed: 10/21/2022]
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24
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Evaluation of a von Willebrand factor three test panel and chemiluminescent-based assay system for identification of, and therapy monitoring in, von Willebrand disease. Thromb Res 2016; 141:202-11. [DOI: 10.1016/j.thromres.2015.12.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 11/06/2015] [Accepted: 12/12/2015] [Indexed: 01/31/2023]
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25
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Favaloro EJ, Bonar RA, Mohammed S, Arbelaez A, Niemann J, Freney R, Meiring M, Sioufi J, Marsden K. Type 2M von Willebrand disease – more often misidentified than correctly identified. Haemophilia 2016; 22:e145-55. [PMID: 27029718 DOI: 10.1111/hae.12903] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/21/2015] [Indexed: 12/24/2022]
Affiliation(s)
- E. J. Favaloro
- Department of Haematology, Sydney Centres for Thrombosis and Haemostasis Institute of Clinical Pathology and Medical Research (ICPMR) Pathology West NSW Health Pathology Westmead Hospital Westmead NSW Australia
| | - R. A. Bonar
- RCPAQAP Haematology St Leonards NSW Australia
| | - S. Mohammed
- Department of Haematology, Sydney Centres for Thrombosis and Haemostasis Institute of Clinical Pathology and Medical Research (ICPMR) Pathology West NSW Health Pathology Westmead Hospital Westmead NSW Australia
| | - A. Arbelaez
- Mater Pathology Mater Health Services Brisbane Qld Australia
| | - J. Niemann
- Mater Pathology Mater Health Services Brisbane Qld Australia
| | - R. Freney
- Mater Pathology Mater Health Services Brisbane Qld Australia
| | - M. Meiring
- Department of Haematology and Cell Biology Faculty of Health Sciences University of the Free State Bloemfontein South Africa
| | - J. Sioufi
- RCPAQAP Haematology St Leonards NSW Australia
| | - K. Marsden
- RCPAQAP Haematology St Leonards NSW Australia
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26
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Towards personalised therapy for von Willebrand disease: a future role for recombinant products. BLOOD TRANSFUSION = TRASFUSIONE DEL SANGUE 2016; 14:262-76. [PMID: 27136426 DOI: 10.2450/2016.0258-15] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 11/04/2015] [Indexed: 11/21/2022]
Abstract
von Willebrand disease (VWD) is reportedly the most common bleeding disorder and is caused by deficiencies and/or defects in the adhesive plasma protein von Willebrand factor (VWF). Functionally, normal VWF prevents bleeding by promoting both primary and secondary haemostasis. In respect to primary haemostasis, VWF binds to both platelets and sub-endothelial matrix components, especially collagen, to anchor platelets to damaged vascular tissue and promote thrombus formation. VWF also stabilises and protects factor VIII in the circulation, delivering FVIII to the site of injury, which then facilitates secondary haemostasis and fibrin formation/thrombus stabilisation. As a result of this, patients with VWD suffer a bleeding diathesis reflective of a primary defect caused by defective/deficient VWF, which in some patients is compounded by a reduction in FVIII. Management of VWD, therefore, chiefly entails replacement of VWF, and sometimes also FVIII, to protect against bleeding. The current report principally focuses on the future potential for "personalised" management of VWD, given the emerging options in recombinant therapies. Recombinant VWF has been developed and is undergoing clinical trials, and this promising therapy may soon change the way in which VWD is managed. In particular, we can envisage a personalised treatment approach using recombinant VWF, with or without recombinant FVIII, depending on the type of VWD, the extent of deficiencies, and the period and duration of treatment.
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27
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Hillarp A, Friedman KD, Adcock-Funk D, Tiefenbacher S, Nichols WL, Chen D, Stadler M, Schwartz BA. Comparison of several von Willebrand factor (VWF) activity assays for monitoring patients undergoing treatment with VWF/FVIII concentrates: improved performance with a new modified automated method. Haemophilia 2015; 21:837-45. [PMID: 26172561 DOI: 10.1111/hae.12703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/31/2015] [Indexed: 11/27/2022]
Abstract
BACKGROUND The ability of von Willebrand factor (VWF) to bind platelet GP Ib and promote platelet plug formation is measured in vitro using the ristocetin cofactor (VWF:RCo) assay. Automated assay systems make testing more accessible for diagnosis, but do not necessarily improve sensitivity and accuracy. OBJECTIVE We assessed the performance of a modified automated VWF:RCo assay protocol for the Behring Coagulation System (BCS(®) ) compared to other available assay methods. METHODS Results from different VWF:RCo assays in a number of specialized commercial and research testing laboratories were compared using plasma samples with varying VWF:RCo activities (0-1.2 IU mL(-1) ). Samples were prepared by mixing VWF concentrate or plasma standard into VWF-depleted plasma. Commercially available lyophilized standard human plasma was also studied. Emphasis was put on the low measuring range. VWF:RCo accuracy was calculated based on the expected values, whereas precision was obtained from repeated measurements. RESULTS In the physiological concentration range, most of the automated tests resulted in acceptable accuracy, with varying reproducibility dependent on the method. However, several assays were inaccurate in the low measuring range. Only the modified BCS protocol showed acceptable accuracy over the entire measuring range with improved reproducibility. CONCLUSIONS A modified BCS(®) VWF:RCo method can improve sensitivity and thus enhances the measuring range. Furthermore, the modified BCS(®) assay displayed good precision. This study indicates that the specific modifications - namely the combination of increased ristocetin concentration, reduced platelet content, VWF-depleted plasma as on-board diluent and a two-curve calculation mode - reduces the issues seen with current VWF:RCo activity assays.
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Affiliation(s)
- A Hillarp
- Malmö Centre for Thrombosis and Haemostasis, Department of Clinical Chemistry, Malmö University Hospital, Malmö, Sweden
| | - K D Friedman
- Medical Sciences Institute, Blood Center of Wisconsin and Medical College of Wisconsin, Milwaukee, WI, USA
| | - D Adcock-Funk
- Colorado Coagulation, Laboratory Corporation of America® Holdings, Englewood, CO, USA
| | - S Tiefenbacher
- Colorado Coagulation, Laboratory Corporation of America® Holdings, Englewood, CO, USA
| | - W L Nichols
- Special Coagulation Laboratory, Mayo Clinic, Rochester, MN, USA
| | - D Chen
- Special Coagulation Laboratory, Mayo Clinic, Rochester, MN, USA
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Costa-Pinto J, Pérez-Rodríguez A, del C Goméz-del-Castillo M, Lourés E, Rodríguez-Trillo A, Batlle J, López-Fernández MF. Diagnosis of inherited von Willebrand disease: comparison of two methodologies and analysis of the discrepancies. Haemophilia 2015; 20:559-67. [PMID: 25077350 DOI: 10.1111/hae.12380] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Diagnostics of von Willebrand disease (VWD) includes assessment of factor VIII (FVIII) coagulant activity, von Willebrand factor (VWF) antigen (VWF:Ag) and VWF ristocetin cofactor activity (VWF:RCo), and more specific tests as multimeric and genetic analyses are necessary for the correct VWD classification. The ACL AcuStar analyzer introduces chemiluminescence (CL) technology in detection of VWD with automated VWF:Ag and VWF:RCo assays. Compare VWF:Ag-ELISA and VWF:RCo by aggregometry conventional assays with new CL VWF:Ag-IL and VWF:RCo-IL assays, investigate the ability to make accurate VWD diagnosis and concordance with multimeric and genetic analyses. 146 patients with congenital VWD (51 Type 1; 34 Type 2A; 16 Type 2B; 31 Type 2M; 5 Type 2N; 9 Type 3) and 30 healthy normal subjects were included. A comparison was made between CL and conventional methods. Diagnostic evaluation included: VWF:RCo/VWF:Ag ratio, multimeric distribution (sodium dodecyl sulfate [SDS]-agarose gel) of VWF and genetic analysis in 110 of 146 patients. CL and conventional methods revealed good correlation. Kappa test agreement diagnosis was >0.8. CL diagnostic sensitivity was 100% and specificity 97%. Multimeric and genetic analysis were of help in clarifying 13 discrepancies of diagnosis between methods, of which six discrepancies were explained by lack of conventional methods′ sensibility. CL methodology can detect VWD and discriminate between type 1, 3 and variant forms and offers an automated, faster, sensitive and less cumbersome method when compared to conventional assays, in particular VWF:RCo by aggregometry. In some cases, even with all phenotype and genetic analyses, discrepancies exist in the classification of VWD.
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Favaloro EJ, Mohammed S. Towards improved diagnosis of von Willebrand disease: Comparative evaluations of several automated von Willebrand factor antigen and activity assays. Thromb Res 2014; 134:1292-300. [DOI: 10.1016/j.thromres.2014.09.024] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Revised: 09/01/2014] [Accepted: 09/20/2014] [Indexed: 01/25/2023]
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Do latex-based immunoturbidimetric assays conquer a prominent role in von Willebrand factor activity detection? Thromb Res 2014; 134:531-2. [DOI: 10.1016/j.thromres.2014.07.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 07/05/2014] [Accepted: 07/07/2014] [Indexed: 11/24/2022]
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Laffan MA, Lester W, O'Donnell JS, Will A, Tait RC, Goodeve A, Millar CM, Keeling DM. The diagnosis and management of von Willebrand disease: a United Kingdom Haemophilia Centre Doctors Organization guideline approved by the British Committee for Standards in Haematology. Br J Haematol 2014; 167:453-65. [PMID: 25113304 DOI: 10.1111/bjh.13064] [Citation(s) in RCA: 227] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Mike A Laffan
- Centre for Haematology, Imperial College London, London, UK
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Evaluating errors in the laboratory identification of von Willebrand disease in the real world. Thromb Res 2014; 134:393-403. [DOI: 10.1016/j.thromres.2014.05.020] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 05/06/2014] [Accepted: 05/13/2014] [Indexed: 11/19/2022]
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Hayward CPM, Moffat KA, Graf L. Technological advances in diagnostic testing for von Willebrand disease: new approaches and challenges. Int J Lab Hematol 2014; 36:334-40. [DOI: 10.1111/ijlh.12220] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 02/28/2014] [Indexed: 12/25/2022]
Affiliation(s)
- C. P. M. Hayward
- Department of Pathology and Molecular Medicine; McMaster University; Hamilton ON Canada
- Department of Medicine; McMaster University; Hamilton ON Canada
- Hamilton Regional Laboratory Medicine Program; Hamilton ON Canada
| | - K. A. Moffat
- Department of Medicine; McMaster University; Hamilton ON Canada
- Hamilton Regional Laboratory Medicine Program; Hamilton ON Canada
| | - L. Graf
- Department of Pathology and Molecular Medicine; McMaster University; Hamilton ON Canada
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Graf L, Moffat KA, Carlino SA, Chan AKC, Iorio A, Giulivi A, Hayward CPM. Evaluation of an automated method for measuring von Willebrand factor activity in clinical samples without ristocetin. Int J Lab Hematol 2014; 36:341-51. [DOI: 10.1111/ijlh.12218] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 02/26/2014] [Indexed: 11/28/2022]
Affiliation(s)
- L. Graf
- Department of Pathology and Molecular Medicine; McMaster University; Hamilton Ontario Canada
| | - K. A. Moffat
- Department of Medicine; McMaster University; Hamilton Ontario Canada
- Hamilton Regional Laboratory Medicine Program; Hamilton Ontario Canada
| | - S. A. Carlino
- Hamilton Regional Laboratory Medicine Program; Hamilton Ontario Canada
| | - A. K. C. Chan
- Department of Pediatrics; McMaster University; Hamilton Ontario Canada
| | - A. Iorio
- Department of Clinical Epidemiology and Biostatistics; McMaster University; Hamilton Ontario Canada
| | - A. Giulivi
- Department of Pathology and Laboratory Medicine; University of Ottawa and Ottawa Hospital; Ottawa Ontario Canada
| | - C. P. M. Hayward
- Department of Pathology and Molecular Medicine; McMaster University; Hamilton Ontario Canada
- Department of Medicine; McMaster University; Hamilton Ontario Canada
- Hamilton Regional Laboratory Medicine Program; Hamilton Ontario Canada
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Stockschlaeder M, Schneppenheim R, Budde U. Update on von Willebrand factor multimers: focus on high-molecular-weight multimers and their role in hemostasis. Blood Coagul Fibrinolysis 2014; 25:206-16. [PMID: 24448155 PMCID: PMC3969155 DOI: 10.1097/mbc.0000000000000065] [Citation(s) in RCA: 141] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 11/27/2013] [Accepted: 12/04/2013] [Indexed: 12/16/2022]
Abstract
Normal hemostasis requires von Willebrand factor (VWF) to support platelet adhesion and aggregation at sites of vascular injury. VWF is a multimeric glycoprotein built from identical subunits that contain binding sites for both platelet glycoprotein receptors and collagen. The adhesive activity of VWF depends on the size of its multimers, which range from 500 to over 10 000 kDa. There is good evidence that the high-molecular-weight multimers (HMWM), which are 5000-10 000 kDa, are the most effective in supporting interaction with collagen and platelet receptors and in facilitating wound healing under conditions of shear stress. Thus, these HMWM of VWF are of particular clinical interest. The unusually large multimers of VWF are, under normal conditions, cleaved by the plasma metalloproteinase ADAMTS13 to smaller, less adhesive multimers. A reduction or lack of HMWM, owing to a multimerization defect of VWF or to an increased susceptibility of VWF for ADAMTS13, leads to a functionally impaired VWF and the particular type 2A of von Willebrand disease. This review considers the biology and function of VWF multimers with a particular focus on the characterization of HMWM - their production, storage, release, degradation, and role in normal physiology. Evidence from basic research and the study of clinical diseases and their management highlight a pivotal role for the HMWM of VWF in hemostasis.
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Affiliation(s)
| | - Reinhard Schneppenheim
- Department of Pediatric Hematology and Oncology, University Medical Center Hamburg-Eppendorf
| | - Ulrich Budde
- Department of Hemostaseology, Medilys Laborgesellschaft, Hamburg, Germany
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Flood VH. Perils, problems, and progress in laboratory diagnosis of von Willebrand disease. Semin Thromb Hemost 2013; 40:41-8. [PMID: 24338593 DOI: 10.1055/s-0033-1363166] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Diagnosis of von Willebrand disease (VWD) merits consideration of personal and family history of bleeding symptoms along with confirmatory laboratory testing. As the latter yields quantifiable results, overreliance on a laboratory diagnosis may occur. However, existing tests for VWD contain potential sources for error. Both intrinsic and extrinsic factors affecting these assays can contribute to either falsely normal or falsely abnormal results. This article will discuss the present available assays as well as new developments in diagnostic testing. A clear understanding of the limitations of VWD testing is helpful for ensuring the correct diagnosis of affected patients.
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Affiliation(s)
- Veronica H Flood
- Division of Pediatric Hematology/Oncology, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin
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Verfaillie CJ, De Witte E, Devreese KMJ. Validation of a new panel of automated chemiluminescence assays for von Willebrand factor antigen and activity in the screening for von Willebrand disease. Int J Lab Hematol 2013; 35:555-65. [DOI: 10.1111/ijlh.12087] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 02/25/2013] [Indexed: 11/27/2022]
Affiliation(s)
- C. J. Verfaillie
- Coagulation Laboratory; Department of Clinical Chemistry, Microbiology and Immunology; Ghent University Hospital; Ghent Belgium
| | - E. De Witte
- Coagulation Laboratory; Department of Clinical Chemistry, Microbiology and Immunology; Ghent University Hospital; Ghent Belgium
| | - K. M. J. Devreese
- Coagulation Laboratory; Department of Clinical Chemistry, Microbiology and Immunology; Ghent University Hospital; Ghent Belgium
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Flood VH, Gill JC, Friedman KD, Christopherson PA, Jacobi PM, Hoffmann RG, Montgomery RR, Haberichter SL. Collagen binding provides a sensitive screen for variant von Willebrand disease. Clin Chem 2013; 59:684-91. [PMID: 23340442 DOI: 10.1373/clinchem.2012.199000] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND von Willebrand factor (VWF) is a multimeric protein that binds platelets and collagen, facilitating hemostasis at sites of vessel injury. Measurement of VWF multimer distribution is critical for diagnosis of variant von Willebrand disease (VWD), particularly types 2A and 2B, but the typical measurement by gel electrophoresis is technically difficult and time-consuming. A comparison of VWF collagen binding (VWF:CB) and VWF multimer distribution was performed to evaluate the utility of VWF:CB as a diagnostic test. METHODS Participants were enrolled in the Zimmerman Program for the Molecular and Clinical Biology of VWD. VWF:CB was analyzed with type III collagen and multimer distribution by agarose gel electrophoresis. The study population included 146 healthy controls, 351 individuals with type 1 VWD, and 77 with type 2 VWD. Differences between individuals with multimer group results within (controls) and outside the reference intervals were assessed with Mann-Whitney tests. RESULTS The mean VWF:CB/VWF antigen ratio was 1.10 for individuals with multimer distribution within the reference intervals and 0.51 for those with multimer distribution outside the reference intervals (P < 0.001). Sensitivity of VWF:CB for multimer abnormalities was 100% for healthy controls, 99% for patients with type 1, and 100% for patients with type 2A and type 2B VWD using a VWF:CB/VWF antigen cutoff ratio of 0.6, and decreased to 99% for all patients with a ratio of 0.7. With the exception of individuals with novel or unclassified mutations, the VWF:CB was able to correctly categorize participants with variant VWD. CONCLUSIONS These findings suggest that VWF:CB may substitute for multimer distribution in initial VWD testing, although further studies are needed to validate the clinical utility of VWF:CB.
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Affiliation(s)
- Veronica H Flood
- Department of Pediatrics, Division of Hematology and Oncology, Medical College of Wisconsin, Milwaukee, WI, USA.
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Abstract
Abstract
A clear understanding of the molecular basis of VWD can guide the choice and interpretation of appropriate diagnostic tests. This review briefly describes the lifecycle and molecular interactions of VWF and how they lead to the current clinical classification. It also includes a brief discussion of the differential diagnosis and general workup of mucocutaneous bleeding, a review of the various VWD subtypes, and pertinent laboratory assays for each, including genetic tests. Finally, common testing pitfalls and diagnostic dilemmas are covered, including the challenge created by the overlap of borderline low VWF levels and mild bleeding.
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Favaloro EJ, Bonar R, Marsden K. Different bleeding risk in type 2A and 2M von Willebrand disease: a 2-year prospective study in 107 patients: a rebuttal. J Thromb Haemost 2012; 10:1455-8; author reply 1458-60. [PMID: 22578129 DOI: 10.1111/j.1538-7836.2012.04781.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
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Branchford BR, Di Paola J. Making a diagnosis of VWD. HEMATOLOGY. AMERICAN SOCIETY OF HEMATOLOGY. EDUCATION PROGRAM 2012; 2012:161-7. [PMID: 23233576 PMCID: PMC5873588 DOI: 10.1182/asheducation-2012.1.161] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A clear understanding of the molecular basis of VWD can guide the choice and interpretation of appropriate diagnostic tests. This review briefly describes the lifecycle and molecular interactions of VWF and how they lead to the current clinical classification. It also includes a brief discussion of the differential diagnosis and general workup of mucocutaneous bleeding, a review of the various VWD subtypes, and pertinent laboratory assays for each, including genetic tests. Finally, common testing pitfalls and diagnostic dilemmas are covered, including the challenge created by the overlap of borderline low VWF levels and mild bleeding.
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Affiliation(s)
- Brian R. Branchford
- Department of Pediatrics, Section of Hematology/Oncology/Bone Marrow Transplantation, University of Colorado Anschutz Medical Campus, Aurora, CO
- Children’s Hospital Colorado, Aurora, CO
- University of Colorado Hemophilia and Thrombosis Center, Aurora, CO
| | - Jorge Di Paola
- Department of Pediatrics, Section of Hematology/Oncology/Bone Marrow Transplantation, University of Colorado Anschutz Medical Campus, Aurora, CO
- Children’s Hospital Colorado, Aurora, CO
- University of Colorado Hemophilia and Thrombosis Center, Aurora, CO
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