An Immunoradiometric Assay for Factor VIII Related Antigen (VIIIRAg) Using Two Monoclonal Antibodies-Comparison with Polyclonal Rabbit Antibodies for Use in von Willebrand’s Disease Diagnosis

1984 ◽  
Vol 52 (03) ◽  
pp. 250-252 ◽  
Author(s):  
Y Sultan ◽  
Ph Avner ◽  
P Maisonneuve ◽  
D Arnaud ◽  
Ch Jeanneau

SummaryTwo monoclonal antibodies raised against FVIII/von Willebrand protein were used in an immunoradiometric assay (IRMA) to measure this antigen in normal plasma and plasma of patients with different forms of von Willebrand’s disease. The first antibody, an IgG1 was used to coat polystyrene tubes, the second one, an IgG2a, iodinated and used in the second step. Both antibodies inhibit ristocetin induced platelet agglutination and react strongly with platelets, megacaryocytes and endothelial cells. The IRMA test using these antibodies showed greater sensitivity than that using rabbit polyclonal anti VIIIRAg antibodies. A good correlation between the two tests was nevertheless found when VIIIRAg was measured in the majority of patient’s plasma. However 5 patients from 3 different families showed more antigenic material in the rabbit antibody IRMA than in the monoclonal antibody IRMA. It is suggested therefore that the monoclonal antibodies identify part of the VIIIR:Ag molecule showing structural abnormalities in these vWd patients, these structural changes remaining undetected by the polyclonal antibodies.

1986 ◽  
Vol 55 (03) ◽  
pp. 338-341 ◽  
Author(s):  
H Takahashi ◽  
W Tatewaki ◽  
M Hanano ◽  
R Nagayama ◽  
A Shibata

SummaryPlatelet-type von Willebrand’s disease (vWD) is a bleeding disorder characterized by a heightened interaction between platelets and von Willebrand factor (vWF) as the result of an intrinsic platelet abnormality (probably in GPIb). Platelet aggregability was nearly normal in response to thrombin, wheat germ agglutinin and Ricinus communis agglutinin in this disorder. Unmodified platelets showed no aggregation upon the addition of peanut agglutinin. Partially purified human vWF induced little aggregation of washed patient platelets, but the aggregation was greatly enhanced in the presence of plasma devoid of vWF. Monoclonal antibodies directed against GPIb and GPIIb/IIIa as well as EDTA completely inhibited vWF-induced aggregation. These results indicate that human vWF induces aggregation of platelet-type vWD platelets in the presence of divalent cations and some plasma cofactor(s), and that both GPIb and GPIIb/IIIa are involved in this aggregation.


Blood ◽  
1984 ◽  
Vol 64 (3) ◽  
pp. 614-621 ◽  
Author(s):  
PM Mannucci ◽  
R Lombardi ◽  
R Bader ◽  
MH Horellou ◽  
G Finazzi ◽  
...  

Abstract In seven patients with acquired von Willebrand's disease (AvWD) associated with lymphoproliferative disorders or benign monoclonal gammopathies, the platelet contents of von Willebrand factor antigen and ristocetin cofactor (vWF:Ag and vWF:RiCof, respectively) were normal. All the multimers of vWF:Ag could be seen in the 1.6% SDS- agarose gel electrophoresis patterns of plasma and platelet lysates. Infusion of 1-deamino-8-D-arginine vasopressin (DDAVP) augmented plasma levels of vWF:Ag and vWF:RiCof of all patients and corrected prolonged bleeding times (BT). However, compared with patients with congenital vWD type I and comparable degrees of baseline abnormalities treated in the same way, vWF:Ag and vWF:RiCof were increased less and cleared more rapidly from plasma and the BT remained normal for a shorter period of time. These studies provide evidence that these AvWD patients have qualitatively normal vWF in plasma, but at lower concentrations, that vWF in platelets is normal both qualitatively and quantitatively, and that cellular vWF can be rapidly released into plasma by DDAVP to correct the hemostatic abnormalities. However, vWF is removed rapidly from plasma, making the correction more transient than in congenital vWD type I.


2002 ◽  
Vol 88 (09) ◽  
pp. 421-426 ◽  
Author(s):  
Stefan Lethagen ◽  
Christina Isaksson ◽  
Charlotta Schaedel ◽  
Lars Holmberg

SummaryHereditary defects of the von Willebrand factor (VWF) gene cause von Willebrand’s disease (VWD) which shows great variability dependent on the nature and location of the mutation. We here describe the characteristics of a substitution of methionine for threonine 1156 in the D3 domain of the VWF, i.e. the domain involved in the intracellular multimerization of pro-VWF dimers. A VWD patient with severe symptoms was a compound heterozygote for the T1156M mutation and a null allele (Q2470X) on the other chromosome. This led to marked reduction of plasma VWF concentration to about 0.05 U/ml and an abnormality of VWF multimers as in type 2A VWD. Expression in vitro of the mutation demonstrated that 1156M-VWF is secreted from COS-7 cells in a much reduced amount and lacking large multimers. When coexpressed with normal VWF 1156M-VWF decreased the secretion of normal VWF in a dose-dependent manner, the secreted VWF showing all the multimers. Two relatives of the propositus were single heterozygotes for the T1156M mutation and were either asymptomatic or had the manifestations of mild type 1 VWD. The expression data and studies of platelet VWF indicate that the T1156M mutation results in intracellular retention of VWF rather than impaired synthesis. Three other members of the family were heterozygotes for the Q2470X mutation and demonstrated the variable expressivity of a null allele.


Haemophilia ◽  
2012 ◽  
Vol 19 (1) ◽  
pp. 76-81 ◽  
Author(s):  
T. C. Abshire ◽  
A. B. Federici ◽  
M. T. Alvárez ◽  
J. Bowen ◽  
M. D. Carcao ◽  
...  

Blood ◽  
1982 ◽  
Vol 59 (3) ◽  
pp. 542-548 ◽  
Author(s):  
HR Gralnick ◽  
MC Cregger ◽  
SB Williams

Abstract The factor VIII/von Willebrand factor (f.VIII/vWf) protein was purified from the plasma of a patient with von Willebrand's disease (vWd). The patient had all of the classic laboratory findings of vWd except for the ristocetin-induced platelet aggregation of his own platelet-rich plasma. The disease has been documented in three generations. Comparison of the purified normal and vWd f.VIIi/vWf protein revealed several abnormalities, including decreased concentration of f.VIII/vWf antigen; decreased specific vWf activity; absence of the larger molecular forms of the f.VIII/vWf protein; carbohydrate deficiencies affecting the sialic acid, penultimate galactose and N- acetylglucosamine moieties; and decreased binding of the f.VIII/vWf protein to its platelet receptor. These studies indicate the multiplicity of biochemical and functional abnormalities associated with the f.VIII/vWf protein in vWd. f.VIII/vWf protein to normal f.VIII/vWf protein that had been treated with 2-mercaptoethanol (2-ME) to reduce the multimer size and then treated with specific exoglycosidases to remove the sialic acid and penultimate galactose residues revealed similar biologic properties.


1987 ◽  
Author(s):  
J Ingerslev ◽  
S Stenbjerg ◽  
A Bukh ◽  
NPH Møller ◽  
J Zeuthen

A recently developed new series of monoclonal antibodies (MAbs) against the von Willebrand factor (vWf) included antibodies strongly inhibiting ( Mab vWf-41) and partly inhibiting ( Mab vWf-33) the collagen binding of vWf. We also characterized two Mabs with interacting properties against the ristocetin induced platelet aggregation (MAbs vWf-21 and vWf-39). These antibodies were conjugated with horse-radish peroxidase (HRP) and examined in different constructions forming two-site MAb ELISA's for plasma vWf:Ag and compared with polyclonal antibody ELISA. Symmetrical MAb-ELISA ( i.e. same Mab for extraction and detection) gave practical no dose-response in the standard assay, whereas any different combination of Mabs gave favourable dose-response relationships in sensitive ELISA's for vWf:Ag. Two different sandwiches were chosen using MAb vWf-33 and Mab vWf-41 at either side of the ELISA. These two assay models gave results of plasma from normal persons almost identical to those obtained with polyclonal antibody ELISA. Also in type I von Willebrand's disease these three assays performed very uniformly. In subtypes II plasma ( IIA: n=7; IIB: n=3, IIC: n=l, IID: n=i) . the assay using vWf-33 for coating and vWf-41-HRP for detection measured considerably lower than the polyclonal ELISA and the Mab-ELISA based on the opposite combination. We believe, that our results are indicative of a molecular defect in the collagen binding domain of vWf in subtype II plasma.


1987 ◽  
Vol 17 (4) ◽  
pp. 182-188 ◽  
Author(s):  
Hoyu Takahashi ◽  
Tsuneyasu Tsukada ◽  
Wataru Tatewaki ◽  
Masaharu Hanano ◽  
Masayoshi Sanada ◽  
...  

Blood ◽  
1986 ◽  
Vol 68 (3) ◽  
pp. 668-672 ◽  
Author(s):  
L Holmberg ◽  
E Berntorp ◽  
M Donner ◽  
IM Nilsson

Abstract In eight members of one family, platelets in platelet-rich plasma aggregated at much lower ristocetin concentrations than normal. Ivy bleeding time was variously prolonged, and von Willebrand factor antigen (vWF:Ag), ristocetin cofactor activity, and factor VIII coagulant activity were decreased. Most of the affected members had had slight to rather severe bleeding symptoms. Platelet-type von Willebrand's disease (vWD) could be ruled out. All multimers of vWF:Ag were found in plasma as well as platelets. Administration of 1-desamino- 8-D-arginine vasopressin (DDAVP) to the propositus did not cause thrombocytopenia, and platelet-poor plasma obtained immediately after did not aggregate normal platelets. The molecular defect in this family, inherited as an autosomal dominant, resembles the one in type IIB because of the response to ristocetin but differs from IIB because all vWF:Ag multimers are present in plasma and the response to DDAVP is atypical. We conclude that this family has a new subtype of vWD and propose that structural as well as functional criteria should be used for a proper classification of vWD.


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