Background Thrombotic thrombocytopenic purpura and the hemolytic-uremic syndrome are severe microvascular disorders of platelet clumping with similar signs and symptoms.
Unusually large multimers of von Willebrand factor, capable of agglutinating circulating platelets under high shear stress, occur in the two conditions.
We investigated the prevalence of von Willebrand factor-cleaving protease deficiency in patients with familial and nonfamilial forms of these disorders.
Methods Plasma samples were obtained from 53 patients with thrombotic thrombocytopenic purpura or hemolytic-uremic syndrome.
Von Willebrand factor-cleaving protease was assayed in diluted plasma samples with purified normal von Willebrand factor as the substrate.
The extent of the degradation of von Willebrand factor was assessed by electrophoresis in sodium dodecyl sulfate-agarose gels and immunoblotting.
To determine whether an inhibitor of von Willebrand factor-cleaving protease was present, we measured the protease activity in normal plasma after incubation with plasma from the patients.
Results We examined 30 patients with thrombotic thrombocytopenic purpura and 23 patients with the hemolytic-uremic syndrome.
Of 24 patients with nonfamilial thrombotic thrombocytopenic purpura, 20 had severe and 4 had moderate protease deficiency during an acute event.
An inhibitor found in 20 of these patients was shown to be IgG in five of five tested plasma samples. (...)
Mots-clés Pascal : Purpura thrombocytopénique thrombotique, Prévalence, Diagnostic différentiel, Hémolyse urémie, Déficit, Inhibiteur enzyme, Facteur Willebrand, Clivage, Peptidases, Hydrolases, Enzyme, Immunoélectrophorèse, Biologie clinique, Traitement, Etude statistique, Enfant, Homme, Adulte, Thrombocyte, Insuffisance rénale, Hémopathie, Anémie hémolytique, Système nerveux pathologie, Appareil urinaire pathologie, Capillaire sanguin pathologie, Peau pathologie, Vaisseau sanguin peau pathologie, Rein pathologie, Immunopathologie, Etiopathogénie, Immunohistochimie
Mots-clés Pascal anglais : Thrombotic thrombocytopenic purpura, Prevalence, Differential diagnostic, Hemolytic uremic syndrome, Deficiency, Enzyme inhibitor, Willebrand factor, Cleavage, Peptidases, Hydrolases, Enzyme, Immunoelectrophoresis, Clinical biology, Treatment, Statistical study, Child, Human, Adult, Platelet, Renal failure, Hemopathy, Hemolytic anemia, Nervous system diseases, Urinary system disease, Capillary vessel disease, Skin disease, Vascular disorders of the skin, Kidney disease, Immunopathology, Etiopathogenesis, Immunohistochemistry
Notice produite par :
Inist-CNRS - Institut de l'Information Scientifique et Technique
Cote : 99-0071890
Code Inist : 002B19C. Création : 31/05/1999.