Measurement of von Willebrand Factor Antigen in Plasma and Platelets with an Enzyme-Linked Immunosorbent Assay Based on Two Murine Monoclonal Antibodies

Objective: To determine the clinical features associated with histologically proven rheumatoid vasculitis (HRV) and the additional diagnostic value of serological markers in an inception cohort of 81 patients with rheumatoid arthritis (RA) suspected of RV. Methods: The presence and number of recently developed extra-articular manifestations (EAMs) and a weighted EAM score, as well as the levels of serological markers, were compared between 31 patients with RA with histologically proven vasculitis and 50 patients with RA in whom vasculitis could not be documented histologically. The following markers were evaluated: circulating immune complexes, complement components C3 and C4, class-specific rheumatoid factors (IgM RF, IgG RF, IgA RF), antineutrophil cytoplasmic antibodies, antinuclear antibodies, antiendothelial antibodies, circulating intercellular adhesion molecule-1 and -3, circulating vascular cell adhesion molecule and E-selectin, cellular fibronectin, von Willebrand factor antigen, and C reactive protein. The diagnostic value of these markers, in addition to the clinical features, was evaluated with logistic regression analysis. Results: Peripheral neuropathy or purpura/petechiae, or both, were the most important clinical features to discriminate patients with RA with and without histologically proven RV. The presence of a high number of EAMs and a higher weighted EAM score in patients with RA suspected of vasculitis were also associated with an increased probability of histologically proven RV. After adjustment for EAMs, only the combination of an increased serum IgA RF level and a decreased serum C3 level appeared to make an additional contribution to the diagnosis histologically proven RV. Evidence of systemic vasculitis was found in a muscle biopsy of the rectus femoris in 9/14 (64%) patients with vasculitis with neuropathy and in 3/11 (27%) patients with purpura/petechiae and vasculitis of the skin. Conclusions: In the diagnostic process of RV the presence of peripheral neuropathy and/or purpura/ petechiae or a high weighted EAM score will increase the probability of histologically proven RV. Of the circulating factors previously suggested to be markers for RV only IgA RF and C3 further increase the probability of histologically proven RV and may be useful to guide diagnostic decisions.

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“…In plasma samples, levels of vWF antigen were determined by ELISA. 28 The normal range is 0.36-2.15 IU/ml.…”

Section: Laboratory Parametersmentioning

confidence: 97%

Diagnostic strategy for the assessment of rheumatoid vasculitis

Voskuyl

Hazes²,

Zwinderman³

et al. 2003

Annals of the Rheumatic Diseases

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“…Finally, inhibition of binding by the vWF peptides Cys474-Val489 and Leu694-Asp709 was studied; both these peptides, which represent sequences flanking the Al loop, were custom-synthesized and purified to homogeneity by h.p.l.c. During e.l.i.s.a., GPIb-associated vWF was revealed by horseradish peroxidase-conjugated anti-vWF monoclonal antibodies 82D6A3 and 82DlE1 previously described for e.l.i.s.a.-based measurement of plasma vWF levels (Tornai et al, 1991).…”

Section: Studies Of Interaction Between Vwf and Gplbmentioning

confidence: 99%

Promotion of binding of von Willebrand factor to platelet glycoprotein Ib by dimers of ristocetin

Hoylaerts

Nuyts

Peerlinck

et al. 1995

Biochemical Journal

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In the absence of high shear forces, the in vitro binding of human von Willebrand factor (vWF) to its platelet receptor glycoprotein Ib (GPIb) can be promoted by two well-characterized mediators, botrocetin and ristocetin. Using purified vWF and GPIb, we have investigated the mechanisms by which ristocetin mediates this binding. Specific binding of vWF monomers to GPIb occurred with a 1:1 stoichiometry, but high-affinity binding required the participation of two ristocetin dimers. Binding was strongly dependent on pH and inhibited by low poly-L-lysine concentrations, indicating ristocetin-dependent charge neutralization during the interaction. With increasing ristocetin concentrations, vWF binding depended progressively less on the involvement of its A1 loop, which is compatible with a model in which the two ristocetin dimers bridge the vWF-GPIb complex on secondary sites. In agreement with this model, the ristocetin-dimer-promoted stabilization of vWF on GPIb was abolished by low concentrations of poly(Pro-Gly-Pro), which is known to complex ristocetin dimers. Mechanistic analysis of the inhibition of vWF binding by the recombinant vWF fragment Leu504-Ser728 (VCL), which covers the entire A1 loop, revealed an affinity of VCL for GPIb comparable with that of the botrocetin-vWF complex for GPIb, and identified a specific but 20-fold lower affinity of VCL in the presence of ristocetin. The proline-rich peptides flanking the vWF A1 loop, Cys474-Val489 and Leu694-Asp709, inhibited vWF binding semispecifically by competitively interfering with the formation of the GPIb-vWF complex rather than by complexation of free ristocetin dimers. In conclusion, ristocetin-promoted binding of vWF to its GPIb receptor results from charge neutralization and interactions involving proline residues in the vicinity of the natural interaction sites present on both GPIb and the A1 domain of vWF.

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“…vWf was purified to homogeneity from lyophilized cryoprecipitate using a gel filtration method, as previously described ( 17). These preparations were used for binding experiments and preparation ofasialo vWf (ASvWf).…”

Section: Purification Of V Wfmentioning

confidence: 99%

“…Preparation ofmAbs mAbs against vWfwere produced by conventional hybridoma technology as previously described ( 17). The IgG fractions were purified from ascites by affinity chromatography on protein A-Sepharose (Pharmacia LKB Biotechnology Inc.) (24).…”

Section: Preparation Ofasvwfmentioning

confidence: 99%

A monoclonal antibody recognizes a von Willebrand factor domain within the amino-terminal portion of the subunit that modulates the function of the glycoprotein IB- and IIB/IIIA-binding domains.

Tornai

Arnout²,

Deckmyn³

et al. 1993

J. Clin. Invest.

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We developed a monoclonal antibody, 1C1E7, against vWf that increases ristocetin-induced platelet aggregation in a dose-dependent manner and lowers the threshold concentration of ristocetin needed to obtain a full aggregatory response. The platelet aggregatory effect of asialo vWf (ASvWf) also is enhanced by 1CIE7, in the presence or absence of glycoprotein (GP) Ilb/IlIa receptor antagonism. In the presence of ristocetin, both intact 1ClE7 and its Fab fragments enhance specific binding of '25I-vWf to platelets. With 1ClE7, the intermediate and higher molecular weight multimers of vWf are preferentially bound to both GP lb and GP IIb/IIIa. Thrombin-induced 125I-vWf binding to GP IIb/Illa also is increased by 1ClE7. Maximal binding of 1C1E7 to vWf corresponds to 0.97 mol/mol vWf monomer with a Kd of 4.7 x 10-10 M. 1ClE7 reacts with a 34 /36-kD tryptic fragment (III-T4) and a 34-kD plasmic fragment (P34), which localizes the epitope between amino acid residues 1 and 272; this was confirmed by NH2-terminal amino acid sequencing. Finally, platelet aggregation by ASvWf was associated with a sharp rise in intracellular Ca2+ only in the presence of 1C1E7. An antibody-mediated conformational change of vWf may result in an improved presentation of the GP Ib-and GP IIb/ IIIa-binding domains of mainly the larger multimers; the increased density of vWf on the platelet surface leads to platelet activation. The antibody may thus recognize a domain of relevance for vWf physiology. (J. Clin. Invest. 1993. 91:273-282.)

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Measurement of von Willebrand Factor Antigen in Plasma and Platelets with an Enzyme-Linked Immunosorbent Assay Based on Two Murine Monoclonal Antibodies

Cited by 12 publications

References 32 publications

Diagnostic strategy for the assessment of rheumatoid vasculitis

Diagnostic strategy for the assessment of rheumatoid vasculitis

Promotion of binding of von Willebrand factor to platelet glycoprotein Ib by dimers of ristocetin

A monoclonal antibody recognizes a von Willebrand factor domain within the amino-terminal portion of the subunit that modulates the function of the glycoprotein IB- and IIB/IIIA-binding domains.

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