Functional and Immunological Assays of F VIII in 133 Haemophiliacs - Characterization of a Subgroup of Patients with Mild Haemophilia A and Discrepancy in 1- and 2-Stage Assays
- 1 April 1988
- journal article
- research article
- Published by Georg Thieme Verlag KG in Thrombosis and Haemostasis
- Vol. 59 (02), 202-206
- https://doi.org/10.1055/s-0038-1642754
Abstract
A systematic study of the levels of FVIII antigen and activity was done in 133 haemophiliacs. No measurable antigen was demonstrated in the 60 severe haemophiliacs, with the exception of 3 patients with levels ranging between 1.5 and 4.5 U/dl, which corresponded to a dramatic FVIII deficiency. The situation was more complex with the 73 moderate and mild haemophiliacs: 39 of them (53.4%) had a partial, concordant deficiency of both the antigen and the procoagulant activity (1- and 2-stage methods), likely corresponding to a decrease in the synthesis of normal FVIII. The conclusion for the other 34 patients, was a qualitative abnormality of FVIII, the levels of antigen in comparison with the procoagulant activity (1-stage method) appearing to be either very reduced (n = 6) or even nil (n = 8), or on the contrary very much higher (n = 20) or normal. For 11 patients in this last category, we found a clear discrepancy between the procoagulant activity levels obtained with the 2 different techniques, the 1-stage levels being higher than the 2-stage levels. This discrepancy which was stable with restudy on multiple occasions and found in different members of the same families was remedied when vWF was absent in one-stage assay. This suggests that we have identified a variant of haemophilia A with an inherited abnormality of FVIII characterized by an in vitro vWF-dependent expression of procoagulant activity.Keywords
This publication has 15 references indexed in Scilit:
- Detection of factor VIII/coagulant antigen in human liver tissueNature, 1983
- Heterogeneity of haemophilia A: a study with three different antiseraBritish Journal of Haematology, 1982
- Immunologic studies of factor VIII coagulant activity (VIII:C) 1. Assays based on a haemophilic and an acquired antibody to VIII:CThrombosis Research, 1981
- Inheritable Molecular Variants of Moderate and Mild Hemophilia AActa Medica Scandinavica, 1981
- Immunologic studies on the relationship between FVIII related antigen and FVIII procoagulant activityThrombosis Research, 1980
- An Immunoradiometric Assay for Procoagulant Factor VIII Antigen: Results in Haemophilia, von Willebrand's Disease and Fetal Plasma and SerumBritish Journal of Haematology, 1979
- Radioimmunoassay for coagulant factor VIII-related antigen (VIII:CAg)Thrombosis Research, 1979
- Immunoradiometric measurement of the factor VIII procoagulant antigen.JCI Insight, 1978
- A More Uniform Measurement of Factor VIII InhibitorsThrombosis and Haemostasis, 1975
- The Assay of Antihaemophilic-Globulin ActivityBritish Journal of Haematology, 1955