Reactivity of small molecular forms of human factor VIII/von Willebrand factor with botrocetin and anti-factor VIII-coated latex particles.
Two recently developed tests for measurement of factor VIII/von Willebrand factor (FVIII/vWF), i.e. platelet agglutination by botrocetin and a kinetic latex antigen assay, were compared with ristocetin cofactor and electroimmunoassay, in respect with FVIII/vWF size-distribution. FVIII/vWF was measured in six cases of atypical von Willebrand's disease (type II), in gel-filtered fractions of normal cryoprecipitate and in the course of depolymerization of purified normal FVIII/vWF by disulfide reduction. Small molecular forms of FVIII/vWF from normal and variant type II plasma, and those derived by disulfide reduction of high-molecular weight FVIII/vWF, showed remarkably decreased reactivity in ristocetin-, botrocetin- and latex-assay. We conclude that for botrocetin-induced platelet agglutination, as well as for agglutination of antibody-coated latex particles, multiple interactions with repeating subunits of FVIII/vWF are required. As a practical consequence, the combined measurement of FVIII/vWF by the latex test and electroimmunoassay provides a simple tool for discriminating between the classical von Willebrand's disease and its variants.
D000906:Antibodies; D000941:Antigens / Q000032:analysis; D001780:Blood Coagulation Tests; D003435:Crotalid Venoms; D005169:Factor VIII / Q000032:analysis* / Q000276:immunology / Q000378:metabolism; D006801:Humans; D007840:Latex; D008863:Microspheres; D008970:Molecular Weight; D012310:Ristocetin; D014841:von Willebrand Factor / Q000032:analysis* / Q000378:metabolism
D000906:Antibodies; D000941:Antigens; D003435:Crotalid Venoms; D007840:Latex; D014841:von Willebrand Factor; D012310:Ristocetin; C030961:botrocetin; D005169:Factor VIII