The Impact of Factor VIII/von Willebrand Factor Concentrate in Inhibitor Development and Management of Patients with Hemophilia A with Inhibitors

2009 ◽  
Vol 02 ◽  
pp. 13
Author(s):  
Caroline Cromwell ◽  
Louis M Aledort ◽  
Margaret Heisel Kurth ◽  
◽  
◽  
...  

The development of inhibitor antibodies that bind to active sites on the factor VIII (FVIII) molecule and neutralize its function and/or accelerate its clearance is the most serious adverse event and safety issue associated with the treatment of hemophilia A. Inhibitor development complicates hemostasis management and increases morbidity and the cost of treatment because bleeding episodes do not respond to standard replacement therapy. Risk factors for inhibitor development include genetic and non-genetic factors. Immunogenicity of the type of product used for replacement therapy may also play a role. Within the category of human-derived products, the presence of von Willebrand factor (vWF) bound to FVIII (vWF/FVIII products) may reduce its immunogenicity. The challenge for inhibitors is to reduce their incidence and, when present, to facilitate their eradication. Factor-bypassing agents have been used to treat acute bleeds in patients who have inhibitors. Immune tolerance induction (ITI) therapy is an alternative approach whose goal is to create tolerance to inhibitors and return patients to their native state. The use of ITI therapy has raised many questions, including the optimal regimen and cost. The basic science data on reduced immunogenicity of vWF/FVIII-containing products and their success in achieving ITI have given us an incentive to continue to explore this approach to both primary and secondary ITI.

Blood ◽  
2000 ◽  
Vol 96 (3) ◽  
pp. 958-965 ◽  
Author(s):  
Marc Jacquemin ◽  
Renaud Lavend'homme ◽  
Abdellah Benhida ◽  
Beatrijs Vanzieleghem ◽  
Roseline d'Oiron ◽  
...  

Abstract The mechanisms responsible for the low factor VIII (fVIII) activity in the plasma of patients with mild/moderate hemophilia A are poorly understood. In such patients, we have identified a series of fVIII mutations (Ile2098Ser, Ser2119Tyr, Asn2129Ser, Arg2150His, and Pro2153Gln) clustered in the C1 domain and associated with reduced binding of fVIII to von Willebrand factor (vWf). For each patient plasma, the specific activity of mutated fVIII was close to that of normal fVIII. Scatchard analysis showed that the affinity for vWf of recombinant Ile2098Ser, Ser2119Tyr, and Arg2150His fVIII mutants was reduced 8-fold, 80-fold, and 3-fold, respectively, when compared with normal fVIII. Given the importance of vWf for the stability of fVIII in plasma, these findings suggested that the reduction of fVIII binding to vWf resulting from the above-mentioned mutations could contribute to patients' low fVIII plasma levels. We, therefore, analyzed the effect of vWf on fVIII production by Chinese hamster ovary (CHO) cells transfected with expression vectors for recombinant B domain-deleted normal, Ile2098Ser, Ser2119Tyr, and Arg2150His fVIII. These 3 mutations impaired the vWf-dependent accumulation of functional fVIII in culture medium. Analysis of fVIII production by transiently transfected CHO cells indicated that, in addition to the impaired stabilization by vWf, the secretion of functional Ile2098Ser and Arg2150His fVIII was reduced about 2-fold and 6-fold, respectively, by comparison to Ser2119Tyr and normal fVIII. These findings indicate that C1-domain mutations resulting in reduced fVIII binding to vWf are an important cause of mild/moderate hemophilia A.


2012 ◽  
Vol 101 (6) ◽  
pp. 2055-2065 ◽  
Author(s):  
Dipak S. Pisal ◽  
Matthew P. Kosloski ◽  
C. Russell Middaugh ◽  
Richard B. Bankert ◽  
Sathy V. Balu-iyer

2017 ◽  
Vol 92 (6) ◽  
pp. E94-E96 ◽  
Author(s):  
Veerle Labarque ◽  
Vanitha Perinparajah ◽  
Vanessa Bouskill ◽  
Ann Marie Stain ◽  
Cindy Wakefield ◽  
...  

Blood ◽  
1993 ◽  
Vol 81 (10) ◽  
pp. 2644-2651 ◽  
Author(s):  
TC Nichols ◽  
DA Bellinger ◽  
RL Reddick ◽  
SV Smith ◽  
GG Koch ◽  
...  

We have studied the roles of von Willebrand factor (vWF) and factor VIII in arterial thrombosis in four canine phenotypes: normal (n = 6), hemophilia A (n = 11), von Willebrand disease (vWD) (n = 9), and hemophilia A/vWD (n = 1). vWF activity was determined by botrocetin- induced agglutination of fixed human platelets and vWF antigen (vWF:Ag) by Laurell electroimmunoassay and crossed immunoelectrophoresis. Plasma from normal dogs and those with hemophilia A had vWF activity, vWF:Ag, and a full range of vWF:Ag multimers on gel electrophoresis equivalent to normal canine plasma pool. Platelet cytosol contents were isolated by freezing and thawing, triton X-100 solubilization, or sonication of washed platelets with and without protease inhibitors and inhibitors of platelet activation. Washed platelets were also stimulated with calcium ionophore and MgCl2. There was no measurable vWF activity or vWF:Ag in platelet lysates or releasates in any dog regardless of phenotype. All dogs were studied using a standard arterial stenosis and injury procedure to induce arterial thrombosis. Thromboses were detected by cyclic reductions in Doppler blood flow velocity. Vessels were examined by light and scanning electron microscopy. Thrombosis developed in the arteries of normal (9 of 10) and hemophilia A dogs (16 of 16) but in none of the vWD dogs (0 of 10). Infusion of canine vWF cryoprecipitate into vWD dogs markedly shortened bleeding time but did not support thrombosis as seen in dogs with vWF in the plasma and subendothelium. Thrombosis, then, fails to occur when vWF is absent from the plasma and subendothelial compartments or present only in the plasma compartment. These data are consistent with the hypothesis that vWF in the plasma and subendothelium supports thrombosis. Neither plasma FVIII nor platelet vWF is essential for thrombosis in this model.


Blood ◽  
2000 ◽  
Vol 96 (3) ◽  
pp. 958-965 ◽  
Author(s):  
Marc Jacquemin ◽  
Renaud Lavend'homme ◽  
Abdellah Benhida ◽  
Beatrijs Vanzieleghem ◽  
Roseline d'Oiron ◽  
...  

The mechanisms responsible for the low factor VIII (fVIII) activity in the plasma of patients with mild/moderate hemophilia A are poorly understood. In such patients, we have identified a series of fVIII mutations (Ile2098Ser, Ser2119Tyr, Asn2129Ser, Arg2150His, and Pro2153Gln) clustered in the C1 domain and associated with reduced binding of fVIII to von Willebrand factor (vWf). For each patient plasma, the specific activity of mutated fVIII was close to that of normal fVIII. Scatchard analysis showed that the affinity for vWf of recombinant Ile2098Ser, Ser2119Tyr, and Arg2150His fVIII mutants was reduced 8-fold, 80-fold, and 3-fold, respectively, when compared with normal fVIII. Given the importance of vWf for the stability of fVIII in plasma, these findings suggested that the reduction of fVIII binding to vWf resulting from the above-mentioned mutations could contribute to patients' low fVIII plasma levels. We, therefore, analyzed the effect of vWf on fVIII production by Chinese hamster ovary (CHO) cells transfected with expression vectors for recombinant B domain-deleted normal, Ile2098Ser, Ser2119Tyr, and Arg2150His fVIII. These 3 mutations impaired the vWf-dependent accumulation of functional fVIII in culture medium. Analysis of fVIII production by transiently transfected CHO cells indicated that, in addition to the impaired stabilization by vWf, the secretion of functional Ile2098Ser and Arg2150His fVIII was reduced about 2-fold and 6-fold, respectively, by comparison to Ser2119Tyr and normal fVIII. These findings indicate that C1-domain mutations resulting in reduced fVIII binding to vWf are an important cause of mild/moderate hemophilia A.


Blood ◽  
1981 ◽  
Vol 57 (1) ◽  
pp. 25-31 ◽  
Author(s):  
PM Mannucci ◽  
ZM Ruggeri ◽  
N Ciavarella ◽  
MD Kazatchkine ◽  
JF Mowbray

Abstract Precipitating antibodies to factor VII/von Willebrand factor can develop in patients with severe homozygous-like von Willebrand's disease following multiple transfusions with blood derivatives. This study of 4 patients treated with cryoprecipitate for 13 different bleeding episodes demonstrates that the occurrence of such antibodies interferes with the management of the disease. The control of mucosal bleeding was poor, whereas more favorable responses were obtained in soft-tissue hemorrhages. These findings probably relate to failure of replacement therapy to shorten the prolonged bleeding time. Immediately after treatment, measurement of plasma factor VIII/von Willebrand factor-related antigen and ristocetin cofactor showed either no increase, or very low values, depending on the pre-infusion antibody titer. Levels of the factor VIII/von Willebrand factor-related procoagulant activity in the circulation were also lower than predicted and usually there was no evidence of the delayed and sustained rise typically observed in uncomplicated von Willebrand's disease. An anamnestic rise in antibody titer appeared 6–15 days after treatment and showed no obvious relationship with the amount of cryoprecipitate infused. Replacement therapy invariably caused severe side effects during, or immediately after, concentrate infusion. The results of in vitro studies support the view that these reactions were due to the appearance of circulating immune complexes.


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