ABSTRACT
OBJECTIVE@#To establish a novel flow cytometric immunobead array (FCIA) for detecting plasma von Willebrand factor antigen (vWF:Ag), and to analyze the clinical value of FCIA in predicting the prognosis of patients with ischemic stroke (IS).@*METHODS@#Anti-human vWF monoclonal antibody SZ29 IgG was coated on microspheres overnight, the diluted plasma was added after blocking, then incubated with FITC-conjugated sheep-anti-human vWF IgG polyclonal antibody, and finally detected by flow cytometry. The plasma vWF in 21 case of von Willebrand disease (vWD) and 105 controls (CTL) were detected by FCIA and ELISA, so as to carry out methodological assessment. Plasma vWF:Ag of 61 IS patients was detected by FCIA and the data of prognosis followed-up for 2-year were collected.@*RESULTS@#The linear fitting of FCIA was good (R2=0.99) without significant difference between FCIA and ELISA. The Bland-Altman bias was 1.12% with 95% limits of agreement that spanned from -45.06% to 47.30%, and the slope of the linear regression was 0.97 (r=0.86, P＜0.01). Importantly, the FCIA method was faster than ELISA, and superior to the ELISA in the detection of low levels of vWF:Ag. The levels of vWF:Ag, vWF:GPIbR and vWF:CB in IS patients were significantly higher than those in healthy controls (Z=8.36, 8.71, 6.22, respectively, P＜0.01).@*CONCLUSION@#The FCIA for detecting plasma vWF:Ag is not only an effective supplement to ELISA, but also the efficiency is faster and more sensitive, thus improves the diagnosis of type 3 vWD. Elevated levels of vWF: Ag in IS patients indicate the poor recovery of daily activities and prognosis.
ABSTRACT
OBJECTIVE@#To establish a novel flow cytometric immunobead array (FCIA) for detecting plasma von Willebrand factor activity (vWF:GPIbR) and apply it in ischemic stroke (IS).@*METHODS@#Microspheres coated with anti-human platelet glycoprotein Ibα (GPIbα) monoclonal antibody SZ151 IgG, were incubated with recombinant fragment of GPIbα, then added ristocetin and plasma, finally incubated with FITC-conjugated sheep-anti-human vWF IgG polyclonal antibody, and detected by flow cytometry. vWF antigen (vWF:Ag), vWF:GPIbR, and vWF collagen binding assay (vWF:CB) were also included for evaluating vWF levels in IS patients.@*RESULTS@#The intra-assay coefficient variations (CVs) and inter-assay CVs of FCIA were 7.7% and 13.5%, respectively. The slope of the linear regression was 0.9739 (r=0.855, P<0.001), and the Bland-Altman bias was 9.95%, indicating a good correlation between FCIA and ELISA. The FCIA had better sensitivity, specificity and accuracy as compared with those by ELISA (P<0.05). The levels of vWF:Ag, vWF:GPIbR and vWF:CB in IS patients were significantly higher in comparison with those in healthy controls (H=7.8, 6.4, 6.2, respectively, P<0.01), the level of vWF:GPIbR in IS patients positively correlated with levels of vWF:Ag, high-sensitivity C-reactive protein, Autar score and hospitalization time.@*CONCLUSION@#The FCIA for detecting plasma vWF:GPIbR is more specific and accurate than ELISA. The vWF:GPIbR is involved in the paroxysm of IS, which could be used to evaluate the risk of thrombosis in IS patients.