The von Willebrand factor collagen-binding activity assay: clinical application

Abstract

A collagen type III based collagen-binding assay was developed for measuring the functional activity of the von Willebrand factor. The assay had a low coefficient of variance (4.8%) for normal values under optimized conditions. The results of the collagen-binding activity (CBA) assay correlated with ristocetin cofactor activity tested in normal plasma samples (n=29). We found that the CBA of blood group O is lower than that of other blood groups. The test was used for the diagnosis of von Willebrand's disease (VWD) and for estimating the response to treatment with DDAVP (1-deamino-D-arginine-8 vasopressin) and factor VIII concentrate. A mean ratio of VWF antigen (VWF:Ag) to CBA of 1.5 indicated type 1 and of 2.7 indicated type 2 VWD. The increase in the collagen-binding activity of VWF released in type 1 VWD patients (n=7) after treatment with DDAVP was higher than the increase in the VWF antigen; this is characteristic of very high multimers with greater functional activity. Factor VIII concentrate Koate-HP (Bayer) administered to a patient with VWD type 3 had a mean residence time of 12.6 h for VWF:Ag and 11.2 h for CBA. These findings suggest that the collagen-binding assay is a useful test for measuring the functional activity of VWF in plasma samples, factor VIII concentrates, as well as for estimating the outcome of treatment.

Increased von Willebrand factor parameters in children with febrile seizures

“…Measurement of VWF:CB is a very sensitive test to detect the freshly secreted VWF due to the content of high molecular weight multimers. Thus, as response to AVP, the increase in VWF:CB is higher than the increase in VWF:Ag reflecting this selective release of very high molecular weight multimers with greater functionality and thus greater capacity to bind to collagen [24]. Our VWF:CB assay uses Collagen type I, so that this assay is even more precise to measure VWF:activity and to detect VWF high molecular weight multimers than other VWF:activity tests [17].…”

The Role of the von Willebrand Factor Collagen-Binding Assay (VWF:CB) in the Diagnosis and Treatment of von Willebrand Disease (VWD) and Way Beyond: A Comprehensive 36-Year History

“…Another study utilizing the VWF:CB to help characterize VWF concentrates was performed by Lethagen et al 105 VWF:RCo and VWF:CB correlated with each other, but not with VWF:Ag, and there were substantial differences noted between the six concentrates assessed. Yet more studies performed on VWF-cleaving protease (ADAMTS13) measured by residual VWF:CB activity by Gao et al 106,107 The authors concluded that measurement of the VWF-cleaving protease activity using residual VWF:CB activity was a simple and rapid method for diagnosing TTP, and that the VWF-cleaving protease activity in patients with TTP was markedly lower than those of patients with tumors. The VWF:CB continued to make inroads into transfusion practice when Burnouf et al used the VWF:CB to help assess the content and functional activity of VWF in apheresis plasma.…”