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"Blood coagulation factor VIII"
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Death in the blood : the inside story of the NHS infected blood scandal
Caroline Wheeler has been reporting on the contaminated blood scandal - the worst treatment disaster in the history of the NHS - for over two decades. She has been integral to the campaign for justice for the victims and their families, and played a pivotal role in persuading Prime Minister Theresa May to agree to the infected blood inquiry in 2019.'Death in the Blood' is based on thousands of government documents, court and inquiry transcripts, plus interviews with prime ministers, cabinet ministers, Downing Street advisers, senior civil servants, doctors, and above all the victims and their families whose personal testimony forms the beating heart of this book.
Book
Factor VIII inhibitor and laboratory assay: State of the art
Coagulation factor inhibitors include antibodies that selectively bind and then oppose different plasma proteins that have a pro-coagulant effect. The development of coagulation factor inhibitors can occur against any of the factors involved in coagulation cascades, with the most frequently affected factor VIII (FVIII). Individuals with inherited haemophilia A (HA) May experience the development of these conditions as a result of an immune response to factor replacement therapy or the presence of autoantibodies, which subsequently lead to the onset of acquired HA. The laboratory diagnosis of factor inhibitors necessitates a thorough and systematic methodology that eliminates other plausible reasons for extended screening tests, primarily the activated partial thromboplastin time (APTT). The measurement of inhibitor titre, which is guided by the results of the Bethesda assay, is performed to determine the optimal treatment approach. The purpose of this review for our laboratory is to enhance understanding, offer a framework to place and validate our work, and consequently improve our chances for achieving success. Data obtained from a literature review typically encompasses subjects and methodologies that have been investigated in this field, as well as the currently recognized optimal approaches. The paper summarizes the laboratory research into factor inhibitors and briefly reviews the latest research.
Journal Article
Correction: Synovial gene expression after hemarthrosis differs between FVIII-deficient mice treated with recombinant FVIII or FVIII-Fc fusion protein
[This corrects the article DOI: 10.1371/journal.pone.0320322.].
Journal Article
The changing treatment landscape in haemophilia: from standard half-life clotting factor concentrates to gene editing
Congenital haemophilia A (factor VIII deficiency) and B (factor IX deficiency) are X-linked bleeding disorders. Replacement therapy has been the cornerstone of the management of haemophilia, aiming to reduce the mortality and morbidity of chronic crippling arthropathy. Frequent intravenous injections are burdensome and costly for patients, consequently with poor adherence and restricted access to therapy for many patients worldwide. Bioengineered clotting factors with enhanced pharmacokinetic profiles can reduce the burden of treatment. However, replacement therapy is associated with a risk for inhibitor development that adversely affects bleeding prevention and outcomes. Novel molecules that are subcutaneously delivered provide effective prophylaxis in the presence or absence of inhibitors, either substituting for the procoagulant function of clotting factors (eg, emicizumab) or targeting the natural inhibitors of coagulation (ie, antithrombin, tissue factor pathway inhibitor, or activated protein C). The ultimate goal of haemophilia treatment would be a phenotypical cure achievable with gene therapy, currently under late phase clinical investigation.
Journal Article
High risk of thrombosis in patients with severe SARS-CoV-2 infection: a multicenter prospective cohort study
PurposeLittle evidence of increased thrombotic risk is available in COVID-19 patients. Our purpose was to assess thrombotic risk in severe forms of SARS-CoV-2 infection.MethodsAll patients referred to 4 intensive care units (ICUs) from two centers of a French tertiary hospital for acute respiratory distress syndrome (ARDS) due to COVID-19 between March 3rd and 31st 2020 were included. Medical history, symptoms, biological data and imaging were prospectively collected. Propensity score matching was performed to analyze the occurrence of thromboembolic events between non-COVID-19 ARDS and COVID-19 ARDS patients.Results150 COVID-19 patients were included (122 men, median age 63 [53; 71] years, SAPSII 49 [37; 64] points). Sixty-four clinically relevant thrombotic complications were diagnosed in 150 patients, mainly pulmonary embolisms (16.7%). 28/29 patients (96.6%) receiving continuous renal replacement therapy experienced circuit clotting. Three thrombotic occlusions (in 2 patients) of centrifugal pump occurred in 12 patients (8%) supported by ECMO. Most patients (> 95%) had elevated D-dimer and fibrinogen. No patient developed disseminated intravascular coagulation. Von Willebrand (vWF) activity, vWF antigen and FVIII were considerably increased, and 50/57 tested patients (87.7%) had positive lupus anticoagulant. Comparison with non-COVID-19 ARDS patients (n = 145) confirmed that COVID-19 ARDS patients (n = 77) developed significantly more thrombotic complications, mainly pulmonary embolisms (11.7 vs. 2.1%, p < 0.008). Coagulation parameters significantly differed between the two groups.ConclusionDespite anticoagulation, a high number of patients with ARDS secondary to COVID-19 developed life-threatening thrombotic complications. Higher anticoagulation targets than in usual critically ill patients should therefore probably be suggested.
Journal Article
A bispecific antibody to factors IXa and X restores factor VIII hemostatic activity in a hemophilia A model
Individuals with hemophilia A lack the coagulation factor FVIII and are treated with frequent intravenous injections of FVIII agents. However, many individuals develop antibodies to FVIII and can no longer be treated by FVIII injection. Takehisa Kitazawa and his colleagues report the development of a bispecific antibody to FIXa and FX that mimics the function of FVIII. This antibody reduces bleeding in a nonhuman primate model of hemophilia A, is resistant to the inhibitory effects of FVIII-specific antibodies and has a long half-life after subcutaneous injection.
Hemophilia A is a bleeding disorder resulting from coagulation factor VIII (FVIII) deficiency. Exogenously provided FVIII effectively reduces bleeding complications in patients with severe hemophilia A. In approximately 30% of such patients, however, the 'foreignness' of the FVIII molecule causes them to develop inhibitory antibodies against FVIII (inhibitors), precluding FVIII treatment in this set of patients
1
,
2
,
3
. Moreover, the poor pharmacokinetics of FVIII, attributed to low subcutaneous bioavailability and a short half-life of 0.5 d, necessitates frequent intravenous injections
3
,
4
,
5
. To overcome these drawbacks, we generated a humanized bispecific antibody to factor IXa (FIXa) and factor X (FX), termed hBS23, that places these two factors into spatially appropriate positions and mimics the cofactor function of FVIII. hBS23 exerted coagulation activity in FVIII-deficient plasma, even in the presence of inhibitors, and showed
in vivo
hemostatic activity in a nonhuman primate model of acquired hemophilia A. Notably, hBS23 had high subcutaneous bioavailability and a 2-week half-life and would not be expected to elicit the development of FVIII-specific inhibitory antibodies, as its molecular structure, and hence antigenicity, differs from that of FVIII. A long-acting, subcutaneously injectable agent that is unaffected by the presence of inhibitors could markedly reduce the burden of care for the treatment of hemophilia A.
Journal Article
Acquired Hemophilia A: Current Guidance and Experience from Clinical Practice
In acquired hemophilia A (AHA), autoantibodies to coagulation factor VIII (FVIII) neutralize FVIII activity leading to a potentially severe bleeding diathesis that carries a high rate of morbidity and mortality. This disorder is rare and occurs mainly in adults over 60 years of age or in the postpartum period. The diagnosis should be suspected in patients with new-onset bleeding without a personal or family history of bleeding and can be confirmed via specific assays for FVIII inhibitors. Treatment involves both hemostatic therapies to decrease bleeding and immune modulation strategies to re-establish immune tolerance to FVIII. There are limited data on treatment for refractory disease, based mostly on small case series. Registry studies have informed consensus guidelines for optimal hemostatic therapies and initial immunosuppressive therapies. Additional studies are needed to evaluate novel hemostatic agents and develop biomarkers to risk-stratify treatment while limiting adverse events.
Journal Article
Differences in coagulation-relevant parameters: Comparing cryoprecipitate and a human fibrinogen concentrate
Variable fibrinogen content within cryoprecipitate makes accurate dosing challenging in patients with coagulopathic bleeding, in addition to pathogen transmission risks associated with its administration. Purified and standardized human fibrinogen concentrates (HFCs) represent reliable alternatives. Full cryoprecipitate characterization is required to inform selection of an appropriate fibrinogen source for supplementation therapy. Extended biochemical comparison of pooled cryoprecipitate and HFC (Fibryga, Octapharma) was performed using commercially available assays to determine levels of variability in cryoprecipitate and HFC. In addition to standard procoagulant factors, measurements included activities of platelet-derived microparticles (PMPs) and plasminogen, and levels of fibrin degradation products. Cryoprecipitate contains lower fibrinogen levels than HFC (4.83 vs.19.73 g/L; p<0.001), translating to approximately half the amount of fibrinogen per standard cryoprecipitate dose (two pools, pre-pooled from five donations each) vs. HFC (2.14 vs. 3.95 g; p<0.001). Factor XIII (FXIII) levels were also lower in cryoprecipitate vs. HFC (192.17 vs. 328.33 IU/dL; p = 0.002). Levels of procoagulants in cryoprecipitate, such as von Willebrand Factor (VWF) and factor VIII (FVIII), were highly variable, as was PMP activity. A standard cryoprecipitate dose contains significantly higher levels of measured plasminogen and D-dimer fragments than a standard HFC dose. The tested HFC is a more reliable fibrinogen and FXIII source for accurate dosing compared with cryoprecipitate. Cryoprecipitate appears considerably less predictable for bleeding management due to wide variation in pro- and anticoagulation factors, the presence of PMPs, and the potential to elevate VWF and FVIII to prothrombotic levels.
Journal Article
