Differential identification of a rare form of platelet‐type (pseudo‐) von Willebrand disease (VWD) from Type 2B VWD using a simplified ristocetin‐induced‐platelet‐agglutination mixing assay and confirmed by genetic analysis

Favaloro, Emmanuel J.; Patterson, David; Denholm, Anna; Mead, Scott; Gilbert, Ann; Collins, Anne T.; Estell, Jane; George, Peter M.; Smith, Mark

doi:10.1111/j.1365-2141.2007.06850.x

Cited by 40 publications

(56 citation statements)

References 7 publications

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“…Type 2A or 2M patients were then subclassified by the in‐house multimer results. Type 2B patients were classified by genetic mutation or historical diagnosis of type 2B VWD by low‐dose RIPA12 (see Figure 1). Type 2N VWD were included by the presence of genetic mutation linked to 2N VWD, reduced or absent FVIII/VWF binding 13…”

Section: Methodsmentioning

confidence: 99%

Evaluation of a semi‐automated von Willebrand factor multimer assay, the Hydragel 5 von Willebrand multimer, by two European Centers

Bowyer¹,

Goodfellow²,

Seidel³

et al. 2018

Research and Practice in Thrombosis and Haemostasis

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BackgroundThe phenotypic diagnosis of von Willebrand disease (VWD) is a multistep process with classification dependent on the quantification of von Willebrand factor (VWF) multimeric structure. VWF multimer analysis is a technically challenging, lengthy and non‐standardised assay, usually performed in specialist laboratories. Recently, a new semi‐automated multimer assay, the Hydragel 5 von Willebrand multimers (H5VWM) has become available.ObjectivesThis study, performed in two European centres, compared existing in‐house multimer assays to the H5VWM in individuals with and without VWD.ResultsOverall agreement of 91.1% was observed in 74 individuals with normal VWF levels, 57 patients grouped as type 1 VWD, 33 type 2A, 16 type 2B, 28 type 2M, 11 type 2N. Patients tested following Desmopressin or VWF concentrate, with thrombotic thrombocytopenic purpura and acquired von Willebrand syndrome were also evaluated. Many of the discrepancies between methods were in patients with genetic mutations linked to more than one type of VWD including p.R1374C/H and p.R1315C. Quantifiable multimer results were available within one working day. Densitometry improved the interpretation of the multimers with slight structural variations that were not apparent by visual inspection of the in‐house method.Conclusions5VWM was a rapid, sensitive, standardised assay which used existing technology and could be included as an initial screen of VWF multimers in a VWD diagnostic algorithm in conjunction with traditional multimer analysis.

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Section: Methodsmentioning

confidence: 99%

Evaluation of a semi‐automated von Willebrand factor multimer assay, the Hydragel 5 von Willebrand multimer, by two European Centers

Bowyer¹,

Goodfellow²,

Seidel³

et al. 2018

Research and Practice in Thrombosis and Haemostasis

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“…PT-VWD is usually misdiagnosed and considered as type IIB VWD, which shows similar bleeding and phenotypic profiles [131]. This disease results from an abnormally high affinity interaction between the platelet membrane glycoprotein Ib/IX/V complex and VWF.…”

Section: Platelet-type Von Willebrand Diseasementioning

confidence: 99%

Structure and function of von Willebrand factor

Hassan

Saxena

Ahmad

2012

Blood Coagulation &Amp; Fibrinolysis

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von Willebrand factor (VWF) is a long plasma protein that contains many domains and each domain has its own function. VWF exists in a multimeric form and performs varieties of functions in the human body, including thrombus formation and blood coagulation. The crystal structures of three subdomains are known, and, interestingly, all three domains share identical three-dimensional fold with α-β-α sandwiched model. VWF is directly associated with different types of von Willebrand disease. In this review, our aim is to gather recent developments on structure and functions of VWF and its clinical relevance.

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“…Aggregometric and flow cytometric mixing assays were performed by adding patient or control platelet-poor plasma (PPP) to patient or control platelet pellets, in the following combinations: 13 patient platelets/patient plasma, patient platelets/control plasma, control platelets/control plasma, control platelets/patient plasma. Platelet aggregation induced by cryoprecipitate, in an amount equivalent to 60 U/dL of VWF, was studied as previously described.…”

Section: Laboratory Studiesmentioning

confidence: 99%