Evaluation of an heterogeneous group of patients with von Willebrand disease using an assay alternative to ristocetin induced platelet agglutination. (27th August 2015)

• Record Type: Journal Article
• Authors: Stufano, F.; Baronciani, L.; Pagliari, M. T.; Franchi, F.; Cozzi, G.; Garcia‐Oya, I.; Bucciarelli, P.; Boscarino, M.; Peyvandi, F.
• Is Part Of: Journal of thrombosis and haemostasis. Volume 13:Number 10(2015:Oct.)
• Page Start: 1806
• Page End: 1814
• Publication Date: 2015-08-27
• Subjects: Thrombosis -- Periodicals; Hemostasis -- Periodicals; Blood coagulation disorders -- Periodicals; 616.1
• DOI: 10.1111/jth.13062
• Languages: English
• ISSNs: 1538-7933

Abstract

<abstract abstract-type="main" id="jth13062-abs-0001"> <title>Summary</title> <sec id="jth13062-sec-0001" sec-type="section"> <title>Background</title> <p>Diagnosis of von Willebrand disease (VWD) type 2 usually relies on the discrepancy between the von Willebrand factor (VWF) ristocetin cofactor activity (VWF:RCo) and VWF antigen (VWF:Ag). Type 2B patients can be discriminated from other qualitative VWD variants by using ristocetin‐induced platelet agglutination (RIPA) test. The major limitation of RIPA is the requirement of fresh blood sample.</p> </sec> <sec id="jth13062-sec-0002" sec-type="section"> <title>Objectives</title> <p>In this study, we evaluated the VWF gain‐of‐function mutant GPIb binding (VWF:GPIbM) and VWF:RCo assays to investigate whether the VWF:GPIbM/VWF:RCo ratio was able to identify the type 2B variant among an heterogeneous VWD population, previously characterized following the ISTH‐SSC guidelines.</p> </sec> <sec id="jth13062-sec-0003" sec-type="section"> <title>Patients/methods</title> <p>Seventy‐six VWD patients and 31 healthy subjects were evaluated by using VWF:Ag, VWF:RCo, and VWF:GPIbM assays.</p> </sec> <sec id="jth13062-sec-0004" sec-type="section"> <title>Results</title> <p>The mean (minimum–maximum values) VWF:GPIbM/VWF:RCo ratio was higher in type 2B patients (2.53, 0.84–6.11) than in healthy controls (1.05, 0.87–1.34), type 1 (0.85, 0.51–1.15), 2A (1.20, 0.36–2.82), and 2M (1.07, 0.91–1.38) (<italic>P</italic> < 0.0001). Type 2B variants were divided into four groups (A, B, C, and D) according to their different multimeric patterns. The mean value of the VWF:GPIbM/VWF:RCo ratio in the four groups showed an increasing trend from group A (1.08) to D (3.69), proportional to the loss of high molecular weight multimers. Among 32 type 2B patients, previously diagnosed with RIPA, 8 (mainly with a type I New York/Malmö phenotype) were not confirmed using the VWF:GPIbM/VWF:RCo ratio.</p> </sec> <sec id="jth13062-sec-0005" sec-type="section"> <title>Conclusions</title> <p>Whenever the RIPA test is not feasible, the VWF:GPIbM/VWF:RCo ratio might help to identify severe type 2B VWD patients.</p> </sec> </abstract>