Life-threatening bleeding in a case of autoantibody-induced factor VII deficiency.
ABSTRACT A male patient presented with life-threatening bleeding induced by autoantibody-induced factor VII (F.VII) deficiency. This patient had macroscopic hematuria, skin ecchymosis, gastrointestinal bleeding, and a neck hematoma that was causing disturbed respiration. He developed acute renal failure and acute hepatic failure, probably due to obstruction of the ureters and the biliary tract, respectively. Although activated partial thromboplastin time was normal, prothrombin time (PT) was remarkably prolonged at 71.8 seconds compared to 14.0 seconds in a normal control. Both the immunoreactive level of F.VII antigen and the F.VII activity of the patient's plasma samples were < 1.0% of normal. Although an equal part of normal plasma was added to the patient's plasma, PT was not corrected. The patient's plasma inhibited F.VII activity. These findings suggested the presence of a plasma inhibitor for F.VII. After administration of large doses of methylprednisolone, PT was gradually shortened and plasma levels of F.VII increased over time. Bleeding, acute renal failure, and acute hepatic failure improved markedly following the steroid treatment. These observations suggest that life-threatening bleeding can be induced by autoantibody-induced F.VII deficiency and that immunosuppressive therapy using large doses of steroid can be successful in inhibiting the production of the autoantibody.
- [Show abstract] [Hide abstract]
ABSTRACT: PURPOSE: Human factor VIIa (FVIIa) is commonly used as bypassing therapy to treat bleeding episodes in hemophilia patients with neutralizing antibodies to factors VIII (FVIII) or IX (FIX). There is a need for a suitable animal model to assess the immunogenicity of new FVIIa products during preclinical development. The aim of this study was the design of a novel transgenic mouse model with immune tolerance to human FVIIa. METHODS: The model was generated by transgenic expression of human F7 cDNA. FVIIa-specific immune responses after treatment with human FVIIa were assessed by analyzing circulating antibodies, antibody producing plasma cells and CD4(+) T cells. RESULTS: In contrast to wild-type mice, human FVII transgenic mice did not develop antibodies when treated with human FVIIa. The immune tolerance was specific and could be broken by application of human FVIIa together with a strong stimulus of the innate immune system. Break of tolerance was associated with increased numbers of pro-inflammatory FVIIa-specific CD4(+) T cells. CONCLUSIONS: The new mouse model is suitable to study the influence of the innate immune system on maintenance and break of immune tolerance against FVIIa and could be used to assess the immunogenicity of new FVIIa products during pre-clinical development.Pharmaceutical Research 06/2013; · 4.74 Impact Factor
- Pediatrics International 07/2008; 50(3):403-5. · 0.88 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Acquired isolated FVII deficiency not due to vitamin K deficiency or liver disease is rare and often associated with severe bleeding. We present a case of transient acquired factor VII deficiency associated with major bleeding, successfully treated with twice daily intermittent intravenous recombinant activated factor VII (rFVIIa) (NovoSeven; Novo Nordisk). The severe transient reduction in factor VII coagulant activity (FVII:C) levels, unresponsive to fresh frozen plasma and vitamin K administration, raise the possibility of an acquired inhibitor to factor VII. However, no inhibitor to factor VII could be demonstrated using protein G sepharose adsorption, or a Bethesda assay using IgG purified from patient plasma. There are few reports of the use of rFVIIa in this setting and this case suggests that rFVIIa is effective therapy, and should be considered early when acquired factor VII deficiency is associated with severe bleeding.Blood Coagulation and Fibrinolysis 07/2004; 15(4):347-51. · 1.25 Impact Factor