Von Willebrand factor collagen binding activity in the diagnosis of von Willebrand disease: an alternative to ristocetin co-factor activity?

AbstractInvestigation of 3 families with bleeding symptoms demonstrated a defect in the collagen-binding activity of von Willebrand factor (VWF) in association with a normal VWF multimeric pattern. Genetic analysis showed affected persons to be heterozygous for mutations in the A3 domain of VWF: S1731T, W1745C, and S1783A. One person showed compound heterozygosity for W1745C and R760H. W1745C and S1783A have not been reported previously. The mutations were reproduced by site-directed mutagenesis and mutant VWF expressed in HEK293T cells. Collagen-binding activity measured by immunosorbent assay varied according to collagen type: W1745C and S1783A were associated with a pronounced binding defect to both type I and type III collagen, whereas the principal abnormality in S1731T patients was a reduction in binding to type I collagen only. The multimer pattern and distribution of mutant proteins were indistinguishable from wild-type recombinant VWF, confirming that the defect in collagen binding resulted from the loss of affinity at the binding site and not impairment of high-molecular-weight multimer formation. Our findings demonstrate that mutations causing an abnormality in the binding of VWF to collagen may contribute to clinically significant bleeding symptoms. We propose that isolated collagen-binding defects are classified as a distinct subtype of von Willebrand disease.

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The Interaction of Botrocetin with Normal or Variant von Willebrand Factor (Types IIA and IIB) and Its Inhibition by Monoclonal Antibodies that Block Receptor Binding

Thrombosis and Haemostasis ◽

10.1055/s-0038-1646298 ◽

1992 ◽

Vol 68 (04) ◽

pp. 464-469 ◽

Cited By ~ 9

Author(s):

Y Fujimura ◽

S Miyata ◽

S Nishida ◽

S Miura ◽

M Kaneda ◽

...

Keyword(s):

Monoclonal Antibodies ◽

Von Willebrand Factor ◽

Binding Activity ◽

Von Willebrand Disease ◽

Platelet Glycoprotein ◽

Normal Individuals ◽

Rag 1 ◽

The One ◽

Von Willebrand ◽

Willebrand Factor

SummaryWe have recently shown the existence of two distinct forms of botrocetin (one-chain and two-chain), and demonstrated that the two-chain species is approximately 30 times more active than the one-chain in promoting von Willebrand factor (vWF) binding to platelet glycoprotein (GP) Ib. The N-terminal sequence of two-chain botrocetin is highly homologous to sea-urchin Echinoidin and other Ca2+-dependent lectins (Fujimura et al., Biochemistry 1991; 30: 1957–64).Present data indicate that purified two-chain botrocetin binds to vWF from plasmas of patients with type IIA or IIB von Willebrand disease and its interaction is indistinguishable from that with vWF from normal individuals. However, an “activated complex” formed between botrocetin and IIB vWF expresses an enhanced biological activity for binding to GP Ib whereas the complex with IIA vWF has a decreased binding activity. Among several anti-vWF monoclonal antibodies (MoAbs) which inhibit ristocetin-induced platelet aggregation and/or vWF binding to GPIb, only two MoAbs (NMC-4 and RFF-VIII RAG:1) abolished direct binding between purified botrocetin and vWF. This suggests that they recognize an epitope(s) on the vWF molecule in close proximity to the botrocetin binding site.

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

Thrombosis and Haemostasis ◽

10.1055/s-0038-1657654 ◽

1997 ◽

Vol 78 (02) ◽

pp. 930-933 ◽

Cited By ~ 11

Author(s):

Ping Chang ◽

D L Aronson

Keyword(s):

Von Willebrand Factor ◽

Functional Activity ◽

Binding Activity ◽

Collagen Binding ◽

Binding Function ◽

Cofactor Activity ◽

Von Willebrand ◽

Willebrand Factor ◽

Ristocetin Cofactor ◽

Ristocetin Cofactor Activity

SummaryFive 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.

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Acquired von Willebrand disease caused by an autoantibody selectively inhibiting the binding of von Willebrand factor to collagen

Blood ◽

10.1182/blood.v84.10.3378.3378 ◽

1994 ◽

Vol 84 (10) ◽

pp. 3378-3384 ◽

Cited By ~ 61

Author(s):

PJ van Genderen ◽

T Vink ◽

JJ Michiels ◽

MB van 't Veer ◽

JJ Sixma ◽

...

Keyword(s):

Von Willebrand Factor ◽

Binding Activity ◽

Von Willebrand Disease ◽

Low Grade ◽

Bleeding Tendency ◽

Glycoprotein Ib ◽

Acquired Von Willebrand Disease ◽

Recurrent Epistaxis ◽

Von Willebrand ◽

Willebrand Factor

Abstract An 82-year-old man with a low-grade malignant non-Hodgkin lymphoma and an IgG3 lambda monoclonal gammopathy presented a recently acquired bleeding tendency, characterized by recurrent epistaxis, easy bruising, and episodes of melena, requiring packed red blood cell transfusions. Coagulation studies showed a von Willebrand factor (vWF) defect (Ivy bleeding time, > 15 minutes; vWF antigen [vWF:Ag], 0.08 U/mL; ristocetin cofactor activity [vWF:RCoF], < 0.05 U/mL; collagen binding activity [vWF:CBA], 0.01 U/mL; absence of the high molecular weight multimers of vWF on multimeric analysis). Mixing experiments suggested the presence of an inhibitor directed against the vWF:CBA activity of vWF without significantly inhibiting the FVIII:C, vWF:Ag, and vWF:RCoF activities. The inhibitor was identified as an antibody of the IgM class by immunoabsorption of vWF and inhibitor-vWF complexes from the plasma of the patient. Subsequent immunoprecipitation experiments using recombinant fragments of vWF showed that the inhibitor reacted with both the glycoprotein Ib binding domain (amino acids [aa] 422–826) and the A3 (aa 909–1112) domain of vWF, but not with the A2 (aa 716–908) or D4 (aa 1183–1535) domains. We conclude that the IgM autoantibody inhibits the vWF:CBA activity by reacting with an epitope present on both the glycoprotein Ib and A3 domains of vWF.

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