Development of a novel flow cytometric immunobead array to quantify VWF: Ag and VWF: GPIbR and its application in acute myocardial infarction

Abstract Objectives Both von Willebrand disease ( VWD ) and acute myocardial infarction ( AMI ) involve quantitative and qualitative changes in von Willebrand factor ( VWF ). Our objective was to develop a rapid and precise flow cytometric immunobead array ( FCIA ) to quantify VWF antigen ( VWF :Ag) and ristocetin‐triggered platelet glycoprotein Ib binding ( VWF : GPI bR) and apply it in a clinical setting. Methods Microbeads, coated with monoclonal antibodies for SZ 29 or SZ 151 IgG, were incubated with diluted plasma. VWF ‐binding microbeads were detected with FITC ‐conjugated sheep‐anti‐human VWF IgG by flow cytometry. Plasma VWF :Ag and VWF : GPI bR levels in normal controls ( CTL ; n=105), patients with VWD (n=21), and patients with AMI (n=146) were tested by FCIA and ELISA in parallel. ADAMTS 13 activity and VWF multimer analyses were also implemented. Results Our novel FCIA showed a strong correlation with the ELISA results ( VWF :Ag, r =.855; VWF : GPI bR, r =.813). The intra‐assay coefficient variations ( CV s) of VWF :Ag‐ FCIA and VWF : GPI bR‐ FCIA were 9.2% and 7.7%, respectively, and the interassay CV s were 12.6% and 13.5%, respectively. Plasma VWF :Ag and VWF : GPI bR levels were significantly higher in patients with AMI than in CTL ( P <.0001), whereas the ratios of ADAMTS 13/ VWF :Ag and ADAMTS 13/ VWF : GPI bR were significantly lower ( P <.0001). Levels of plasma ultra‐large VWF ( UL ‐ VWF ) were dramatically increased in patients with AMI . Conclusions The novel VWF :Ag and VWF : GPI bR‐ FCIA assays were found to be simpler, more specific, and more accurate than the classical ELISA method. In addition, elevated VWF : GPI bR and UL ‐ VWF may contribute to the pathogenesis of AMI .