Semiautomatic VWF Multimer Densitometric Analysis: Validation of the Clinical Accuracy and Clinical Implications in Von Willebrand Disease
| Autor: | Johan Boender, Britta A P Laros-van Gorkom, Marjon H. Cnossen, Jeroen Eikenboom, Johanna G. van der Bom, Karina Meijer, Joke de Meris, Karin Fijnvandraat, Karin P M van Galen, Frank W.G. Leebeek, Moniek P.M. de Maat, Ferdows Atiq |
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| Rok vydání: | 2020 |
| Předmět: |
Fviii activity
congenital hereditary and neonatal diseases and abnormalities medicine.medical_specialty biology business.industry Immunology Patient characteristics Cell Biology Hematology Total population medicine.disease Biochemistry Von Willebrand factor hemic and lymphatic diseases Internal medicine biology.protein medicine Von Willebrand disease Current employment In patient Vwf multimers business |
| Zdroj: | Blood. 136:15-16 |
| ISSN: | 1528-0020 0006-4971 |
| DOI: | 10.1182/blood-2020-142287 |
| Popis: | Introduction Von Willebrand factor (VWF) multimer analysis is an essential tool in the diagnosis and classification of von Willebrand disease (VWD). Current visual VWF multimer analysis is observer dependent, time consuming and is inaccurate in detecting subtle changes in multimer patterns. Therefore, recent studies have investigated VWF multimer quantification using semiautomatic densitometric analysis. The accuracy of VWF multimer densitometric analysis in clinical practice needs further investigation before it can be widely used. The aim of the study was to validate the accuracy of VWF multimer densitometric analysis in clinical practice. Additionally, we aimed to identify patient characteristics associated with VWF multimer densitometry outcomes in type 1 and type 2 VWD patients, and we investigated whether subtle differences in VWF multimer pattern are associated with the bleeding phenotype of VWD patients. Methods We included patients from the nationwide Willebrand in the Netherlands (WiN) study. The inclusion criteria of the WiN study were a personal hemorrhagic diathesis or family history of VWD, and historically lowest VWF antigen (VWF:Ag), VWF activity (measured with the monoclonal antibody assay: VWF:Ab) or VWF collagen binding (VWF:CB) ≤0.30 IU/mL or FVIII activity (FVIII:C) ≤0.40 IU/mL in case of type 2N VWD. At inclusion in the WiN study, blood was drawn and patients filled in an extensive questionnaire containing a self-administered Tosetto bleeding score (BS). For multimer analysis, citrated blood samples were separated on 0.9% agarose gel and visualized by Western blotting. We used IMAGEJ for densitometric analysis. The five smallest bands on densitometric images were defined as small multimers, next five bands were defined as medium multimers and the remaining bands were defined as large multimers. Medium-large VWF multimer index was calculated by dividing the patient's multimer ratio (intensity of the medium and large multimers divided by the total intensity of all multimers) by the multimer ratio of a normal control in the same western blot. If no multimers could be detected, the multimer index was set as 0. Results We included 561 VWD patients: 328 type 1, 211 type 2 and 21 type 3 patients. The median age was 44 [IQR 29-58] and 351 patients (62.7%) were female (Table 1). Figure 1 illustrates typical densitometric outcomes of a type 1 VWD patient with normal VWF multimers (A) and a type 2A patient with reduced high-molecular-weight (HMW) VWF multimers (B). Medium-large VWF multimer index was 1.06 [0.99-1.12] in type 1 and 0.53 [0.29-0.89] in type 2 and 0.00 [0.00-0.00] in type 3 VWD. Medium-large VWF multimer index was in patients visually classified as normal, reduced and absent HMW VWF multimers, respectively 1.07 [1.02-1.12], 0.84 [0.71-0.91] and 0.31 [0.20-0.44] (p From VWF activity measurements, medium-large VWF multimer index was strongest correlated with VWF:CB (ρ=0.79, p In type 1 VWD, an increased clearance of VWF (defined as VWFpropeptide/VWF:Ag ratio ≥2.2) was independently associated with lower medium-large VWF multimer index (β=-0.10 (-0.14; -0.07), p In the total population, higher medium-large VWF multimer index was associated with a lower bleeding score: β=-4.6 (-7.2; -2.0), p=0.001, adjusted for age, sex, blood group and type of VWD. Conclusion Semiautomatic densitometric analysis of VWF multimers has an excellent accuracy in clinical practice, and may have an additional value in providing a better understanding of the clinical features such as the bleeding phenotype of VWD patients. Disclosures Atiq: CSL Behring: Research Funding; SOBI: Other: travel grant. Boender:SOBI: Current Employment; CSL Behring: Research Funding. Cnossen:Bayer: Research Funding; Novo Nordisk: Research Funding; Nordic Pharma: Research Funding; Sobi: Research Funding; Takeda: Research Funding; CSL behring: Research Funding; Pfizer: Research Funding; Shire: Research Funding; Baxter: Research Funding. van der Bom:Bayer: Speakers Bureau. Fijnvandraat:SOBI: Research Funding; NovoNordisk: Consultancy; Grifols: Consultancy; Takeda: Consultancy; Roche: Consultancy; CSL Behring: Research Funding; NovoNordisk: Research Funding. Van Galen:Bayer: Research Funding; Takeda: Speakers Bureau; CSL Behring: Research Funding. Laros-Van Gorkom:Baxter: Other: Educational grant; CSL Behring: Other: Educational grant. Meijer:Bayer: Research Funding; Sanquin: Research Funding; Pfizer: Research Funding; Bayer: Speakers Bureau; Sanquin: Speakers Bureau; Boehringer Ingelheim: Speakers Bureau; BMS: Speakers Bureau; Aspen: Speakers Bureau; Uniqure: Consultancy. Eikenboom:CSL Behring: Research Funding; Roche: Other: Teacher on educational activities. Leebeek:Roche: Other: DSMB member for a study; SOBI: Other: Travel grant; Novo Nordisk: Consultancy; Shire/Takeda: Consultancy; Uniqure: Consultancy; Shire/Takeda: Research Funding; CSL Behring: Research Funding. |
| Databáze: | OpenAIRE |
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