Measurement of Factor VIII Procoagulant Antigen in Normal Subjects and in Hemophilia A Patients by an Immunoradiometric Assay and by an Enzyme-Linked Immunosorbent Assay

Hellstern, Peter; Miyashita, C.; Köhler, Michael; Blohn, G. von; Kiehl, R.; Biro, George P.; Schwerdt, Holger; Wenzel, Esther Veronika

doi:10.1159/000215740

Cited by 4 publications

(4 citation statements)

References 14 publications

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“…FVIII protein was measured using an enzyme immunoassay (Immuno). 26 FVIII inhibitor antibodies were measured using a Nijmegenmodified Bethesda assay. 27,28 The CVs of the inhibitor assays were 4.6% within a run and 7.7% between runs.…”

Section: Coagulation Assaysmentioning

confidence: 99%

Phase 1 trial of FVIII gene transfer for severe hemophilia A using a retroviral construct administered by peripheral intravenous infusion

Powell

Ragni

White

et al. 2003

Blood

204

153

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In a phase 1 dose escalation study, 13 subjects with hemophilia A received by peripheral intravenous infusion a retroviral vector carrying a B-domain-deleted human factor VIII (hFVIII) gene. Infusions were well tolerated. Tests for replication competent retrovirus have been negative. Polymerase chain reaction (PCR) analyses demonstrate the persistence of vector gene sequences in peripheral blood mononuclear cells in 3 of 3 subjects tested. Factor VIII was measured in serial samples using both a one-stage clotting assay and a chromogenic assay. While no subject had sustained FVIII increases, 9 subjects had FVIII higher than 1% on at least 2 occasions 5 or more days after infusion of exogenous FVIII, with isolated levels that ranged from 2.3% to 19%. Pharmacokinetic parameters of exogenous FVIII infused into subjects 13 weeks after vector infusion showed an increased half-life (T 1/2 ; P < .02) and area under the curve (AUC, P < .04) compared with prestudy values. Bleeding frequency decreased in 5 subjects compared with historical rates. These results demonstrate that this retroviral vector (hFVIII(V)) is safe and, in some subjects, persists more than a year in peripheral blood mononuclear cells, with measurable factor VIII levels and with increased available FVIII activity (increased T 1/2 and AUC) after infusion of exogenous FVIII concentrate.

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Section: Coagulation Assaysmentioning

confidence: 99%

Phase 1 trial of FVIII gene transfer for severe hemophilia A using a retroviral construct administered by peripheral intravenous infusion

Powell

Ragni

White

et al. 2003

Blood

204

153

View full text Add to dashboard Cite

show abstract

“…FVIII can be recorded by the traditional one‐stage assay or by the chromogenic two‐stage variant. Quantification of the FVIII antigen (FVIII:Ag) can be performed using various ELISA methods utilizing patient’s inhibitor IgG antibodies [26–28], monoclonal antibodies [29] or polyclonal rabbit antibodies [30].…”

Section: The Diagnostic Armamentariummentioning

confidence: 99%

Diagnosis of von Willebrand Disease

Ingerslev

Gürsel

1999

Haemophilia

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The haemorrhagic diathesis in von Willebrand disease (vWD) is caused by a quantitative deficiency or a qualitative defect in the von Willebrand factor (vWF) in plasma and/or platelets causing insufficient primary haemostasis. Since vWF binds and protects factor VIII (FVIII) towards random proteolysis, coagulation may also be impaired in patients with a low plasma level of vWF, and in instances where vWF displays insufficient binding capacity to FVIII. The entity of vWD displays a vast heterogeneity. Apart from rarely occurring acquired cases, vWD is an inherited disorder of autosomal linkage. The major clinical hallmark in vWD is an increased tendency to mucocutaneous bleeding that rarely reach life-threatening proportions, unless vWF is severely reduced or completely absent. Increased bleeding may also occur in sites such as muscles and joints when the level of FVIII is particularly low. Significant progress has recently been achieved through extensive molecular genetic exploration of various forms of vWD. In order to guide treatment and to form a platform for genetic investigation, however, accuracy in diagnosis and phenotypic characterization is important. By means of various laboratory methods, major subclasses of vWD can be differentiated, as presented in another article of this series. Whereas most of the cases of vWD can quite easily be diagnosed and classified using today's diagnostic methods, the most frequently occurring bleeding disorder of all, vWd type 1 of mild degree, continues to challenge clinicians and diagnostic laboratories. The aim of this paper is to review the laboratory methods most commonly used in diagnostic investigation of the patient suspected of vWD.

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“…(1985 and Ingerslev & Stenberg (1986). Hellstern et al (1987) developed an assay using a mixture of human antibodies and mAb. One ELISA using only mAb has been described by Furlong et al (1988) and has been used in the identification of haemophilia carriers.…”

Section: Ukmentioning

confidence: 99%

Development, optimization and use of an enzyme linked immunosorbent assay (ELISA) to measure factor VIII antigen utilizing monoclonal antibodies

Hornsey

Drummond

Eaglesfield

et al. 1992

Transfusion Medicine

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An enzyme linked immunosorbent assay (ELISA) has been developed to measure VIII:Ag in plasma and concentrates. The assay utilizes two commercially available monoclonal antibodies to VIII:Ag and provides an alternative to the established immunoradiometric assay (IRMA). It has the advantage of not requiring the use of radioactive material and human antibodies. The assay sensitivity is 0.006 u/ml and the interassay coefficient of variation is 6.3%. Forty-eight samples with VIII:Ag levels ranging from 0.006 to 1.5 u/ml were assayed by both ELISA and IRMA. The coefficient of correlation between the two assays was 0.89. In addition to measuring human VIII:Ag, it is also possible to detect antigen in several animal plasma and sera.

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Measurement of Factor VIII Procoagulant Antigen in Normal Subjects and in Hemophilia A Patients by an Immunoradiometric Assay and by an Enzyme-Linked Immunosorbent Assay

Cited by 4 publications

References 14 publications

Phase 1 trial of FVIII gene transfer for severe hemophilia A using a retroviral construct administered by peripheral intravenous infusion

Phase 1 trial of FVIII gene transfer for severe hemophilia A using a retroviral construct administered by peripheral intravenous infusion

Diagnosis of von Willebrand Disease

Development, optimization and use of an enzyme linked immunosorbent assay (ELISA) to measure factor VIII antigen utilizing monoclonal antibodies

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