Qualitative and quantitative modifications of von Willebrand factor in patients with essential thrombocythemia and controlled platelet count

Lancellotti, Stefano; Dragani, Alfredo; Ranalli, Paola; Petrucci, Giovanna; Basso, Maria Sole; Tartaglione, R.; Rocca, Bianca; Cristofaro, Raimondo De

doi:10.1111/jth.12967

Cited by 54 publications

(66 citation statements)

References 67 publications

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“…Importantly, individuals with concomitant AVWS were also characterized by higher erythrocyte counts than the remaining subjects, which suggests the potential involvement of increased shear stress in the etiopathogenesis of this bleeding disorder. Also some ET-specific etiopathogenetic mechanisms of AVWS, such as in vivo platelet activation, 25 should be considered.…”

Section: Resultsmentioning

confidence: 99%

Prevalence of acquired von Willebrand syndrome during essential thrombocythemia: a retrospective analysis of 170 consecutive patients

Mital¹,

Prejzner²,

Bieniaszewska³

et al. 2015

Polish Archives of Internal Medicine

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Section: Resultsmentioning

confidence: 99%

Prevalence of acquired von Willebrand syndrome during essential thrombocythemia: a retrospective analysis of 170 consecutive patients

Mital¹,

Prejzner²,

Bieniaszewska³

et al. 2015

Polish Archives of Internal Medicine

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“…The main abnormalities consisted of loss of larger VWF multimers and high proteolysis of VWF, all associated with thrombocytosis, mostly resulting in bleeding . In a previous study on ET, we observed a deficiency of VWF activity and selectively of large VWF multimers over a wide range of platelet counts, rather than in patients with severe thrombocytosis only . This acquired VWF deficiency was likely a continuous phenomenon, driven by high ongoing in vivo platelet activation, which is the hallmark of ET, with consequent platelet‐dependent VWF consumption …”

Section: Introductionmentioning

confidence: 79%

“…VWF:Ag and VWF:Act levels in 41 patients with PV were also compared to the levels measured in 41 patients with ET selected from a previously‐published cohort to be sex, age, and blood group matched with patients with PV (Table ) . While VWF:Ag levels were similar in patients with PV and ET (Figure A), the VWF:Act values were significantly higher in patients with PV as compared to patients with ET (Figure A), and VWF:Act/VWF:Ag ratios were also higher in patients with PV as compared to patients with ET (Figure B).…”

Section: Resultsmentioning

confidence: 99%

“…VWF activity (VWF:Act) was as measured by a collagen‐binding assay using the Asserachrom ELISA kit (Diagnostica Stago, Parsippany, NJ, USA), which explores the collagen‐binding capacity of the high‐molecular‐weight multimers of VWF. The latter were studied with SDS–agarose gel electrophoresis (0.8% agarose, stacking gel −1.5% agarose, running gel), as previously detailed . The deficiency of high‐molecular‐weight multimers of VWF was defined by the VWF:Act/VWF:Ag ratio < 0.6, that has been shown to reflect a loss of high‐molecular‐weight multimers, as in the case of type 2A or 2B von Willebrand disease .…”

Section: Methodsmentioning

confidence: 99%

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Increased von Willebrand factor levels in polycythemia vera and phenotypic differences with essential thrombocythemia

Sacco

Ranalli

Lancellotti

et al. 2020

Research and Practice in Thrombosis and Haemostasis

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Background Acquired von Willebrand factor (VWF) deficiency was described in Philadelphia‐negative myeloproliferative neoplasms, especially in essential thrombocythemia (ET). VWF phenotype in contemporary patients with polycythemia vera (PV) remains less explored. Objectives To characterize the VWF phenotype in PV and to compare VWF phenotype in PV with matched healthy subjects and ET patients. Patients/Methods We studied 48 PV patients, treated according to current recommendations (hematocrit ≤ 45%, on low‐dose aspirin prophylaxis); 48 healthy and 41 subjects with ET, all sex, age, and blood group matched. We measured VWF antigen, activity, multimeric pattern, ADAMTS‐13, and factor VIII (FVIII) antigen. Results In patients with PV, VWF antigen and activity were significantly higher than in healthy subjects (antigen: 119[96‐137] vs 93[79‐107] IU/dL; activity: 114[95‐128] vs 90[79‐107] IU/dL, respectively, medians and interquartile, P < 0.01), with normal multimeric distribution. ADAMTS‐13 levels were similar between patients with PV and healthy subjects. FVIII levels were higher in PV than in healthy subjects (141[119‐169] versus 98[88‐123] IU/dL, respectively, P < 0.01). By multivariable analysis, JAK2‐p.V617F allelic burden, erythrocyte count, and male sex significantly predicted VWF antigen and activity levels. As compared to patients with ET, patients with PV showed similar VWF antigen levels but approximately 40% higher activity (79[49‐104] vs 112[93‐125] IU/dL, respectively, P < 0.01). Conclusions Patients with PV show increased VWF and FVIII levels, predicted by JAK2‐p.V617F burden and erythrocyte count. At variance with ET, acquired VWF defect was not observed in PV. High VWF/FVIII levels may sustain the thrombotic diathesis of PV and may be investigated as biomarkers for risk stratification.

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“…In our cohort, a high percentage of AVWS was found. In contrast, adult studies looking at AVWS in ET reported a much lower prevalence (about 20% of patients) . Nevertheless, Mital et al noted that their younger adult patients developed AVWS more commonly.…”

Section: Discussionmentioning

confidence: 94%

Essential thrombocythemia A retrospective case series

Barg

Toren

Tamary

et al. 2020

Pediatric Blood & Cancer

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Background Essential thrombocythemia (ET) is rare in children, and pediatric guidelines are lacking. Therefore, we aimed to evaluate ET diagnosis and treatment in a pediatric cohort. Procedure Data of patients with ET from three hospitals were reviewed. Molecular diagnosis included JAK2V617F, CALR, and MPL mutations. Patients were evaluated for acquired von Willebrand syndrome (AVWS). Follow‐up included clinical symptoms, adverse events, and treatment. Results Twelve children (median age: 8 years, range 1‐14.5) were included. Mean lag period between the first documentation of thrombocytosis until ET diagnosis was 36 months. Six patients were positive for JAK2V617F and two for CALR mutations. In six of nine patients, AVWS was diagnosed. At diagnosis, only 33% of patients started therapy with aspirin (n = 4) and hydroxyurea (n = 2). In three of eight untreated patients, therapy was added during follow‐up. The cohort was followed for a median of 32.5 months (range: 4‐108 months). Clinical follow‐up disclosed vascular complications in 4 of 12 patients (deep vein thrombosis, n = 1; transient ischemic attack, n = 3). Two females experienced excessive bleeding; both were diagnosed with AVWS. Neither leukemia nor myelofibrosis evolved in our cohort. Conclusion Increased awareness to pediatric ET is warranted, as delayed diagnosis is common. Compared to adults, AVWS may be more prevalent among children with ET.

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Qualitative and quantitative modifications of von Willebrand factor in patients with essential thrombocythemia and controlled platelet count

Abstract: quantitative modifications of von Willebrand factor in patients with essential thrombocythemia and controlled platelet count. J Thromb Haemost 2015; 13: 1226-37.

Cited by 54 publications

References 67 publications

Prevalence of acquired von Willebrand syndrome during essential thrombocythemia: a retrospective analysis of 170 consecutive patients

Prevalence of acquired von Willebrand syndrome during essential thrombocythemia: a retrospective analysis of 170 consecutive patients

Increased von Willebrand factor levels in polycythemia vera and phenotypic differences with essential thrombocythemia

Essential thrombocythemia A retrospective case series

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