Thromb Haemost 1997; 78(02): 930-933
DOI: 10.1055/s-0038-1657654
Rapid Communication
Schattauer GmbH Stuttgart

Plasma Derived von Willebrand Factor Preparations: Collagen Binding and Ristocetin Cofactor Activities

Ping Chang
The Division of Hematology, George Washington University Medical Center, Washington D. C., USA
,
D L Aronson
The Division of Hematology, George Washington University Medical Center, Washington D. C., USA
› Author Affiliations
Further Information

Publication History

Received 31 1996

Accepted after revision 25 March 1997

Publication Date:
12 July 2018 (online)

Summary

Five plasma preparations (11 lots) used in the treatment of von Willebrand’s disease (vWD) were evaluated. The collagen binding function of von Willebrand factor (vWF) containing preparations was compared with the ristocetin cofactor activity and the vWF antigen. Some preparations have higher ratio of functional activity (ristocetin cofactor and collagen binding) relative to the antigen than is found in normal plasma. The ristocetin cofactor activity and the collagen binding activity are tightly correlated (r = .95). Ultracentrifugal (UCF) analysis was used to compare the size distribution of vWf antigen, ristocetin cofactor and collagen binding activity. The sedimentation of all of the vWF parameters in the plasma products was slower than in plasma. In plasma products the ristocetin cofactor activity sediments the most rapidly, the collagen binding activity is slower and the antigen the slowest. The collagen/antigen ratio decreases with decreasing vWF size. Assignment of potency to vWF containing preparations utilizing the collagen binding activity may be more precise and as accurate as with the traditional ristocetin cofactor assay.