Increased prevalence of inhibitors in Hispanic patients with severe haemophilia A enrolled in the Universal Data Collection database
ABSTRACT Neutralizing inhibitors develop in 20-30% of patients with severe factor VIII (FVIII) deficiency. It is well established that Blacks have a higher prevalence of inhibitors than Whites. This is the first study to definitively demonstrate increased inhibitor prevalence in the Hispanic population. We compared inhibitor prevalence among various racial and ethnic groups in a cross-sectional analysis of 5651 males with severe haemophilia A that participated in the Universal Data Collection project sponsored by the Centers for Disease Control and Prevention. We used logistic regression analysis to control for potential confounding variables. We assigned as Hispanic those participants who were white and labelled themselves Hispanic. The prevalence of high-titre inhibitors in the Hispanic participants was 24.5% compared to 16.4% for White non-Hispanic patients (OR 1.4, 95% CI 1.1, 1.7). Possibilities as to the underlying cause of increased inhibitor prevalence in minority ethnic populations include polymorphisms in the FVIII molecule, HLA subtypes and differing inflammatory responses. A better understanding may lead to tailored treatment programmes, or other therapies, to decrease or prevent inhibitor development.
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ABSTRACT: The pathogenesis of inhibitory antibodies has been the focus of major scientific interest over the last decades and several studies on underlying immune mechanisms and risk factors for formation of these antibodies have been performed with the aim of improving the ability to both predict and prevent their appearance. It seems clear that the decisive factors for the immune response to the deficient factor are multiple and involve components of both a constitutional and therapy-related nature. A scientific concern and obstacle for research in the area of hemophilia is the relatively small cohorts available for studies and the resulting risk of confounded and biased results. Careful interpretation of data is recommended in order to avoid treatment decisions based on a weak scientific platform. This review will summarize current concepts of the underlying immunological mechanisms and risk factors for development of inhibitory antibodies in patients with hemophilia A, and discuss how these findings may be interpreted and influence our clinical management of patients. Copyright © 2015 American Society of Hematology.Blood 02/2015; 125(13). DOI:10.1182/blood-2014-08-535328 · 9.78 Impact Factor
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ABSTRACT: The major therapy for haemophilia is plasma derived or recombinant clotting factors which are evolving steadily to increase potency, stability and half-life. Research in the area of haemophilia therapeutics, however, is not restricted only to modifications in the recombinant products, but alternate therapeutic strategies are being developed which are in different phases of experimental and clinical trials. This chapter reviews the diverse molecular innovations which are being developed for alternate therapeutic approaches in haemophilia. The data is mainly extracted from the literature and the Conference abstracts. Some of the novel therapeutic approaches include inhibition of anticoagulant pathway factors (activated protein C, antithrombin, tissue factor pathway inhibitor) by monoclonal antibodies, peptide inhibitors, DNA or RNA aptamers, use of variant coagulation factors (factor Xa, factor Va) which are more resistant to inactivation or enzymatically more active and antibody-mediated therapy including a humanized anti-factor IXa/X bispecific antibody mimicking factor VIII. Other approaches include nonsense mutation suppression, induction of prothrombotic microparticles by P-selectin-immunoglobulin chimeras, suppression of fibrinolytic potential either by antifibrinolytics or by the use of mutant molecules of fibrinolytic inhibitors. Few products are proposed as ‘stand alone’ treatment for haemophilia, while a few can be used as adjuvant therapies to recombinant factors with an aim to reduce the amount of factor intake. All efforts are underway to produce an alternate, novel drug for haemophilia which will have an increased half-life, subcutaneously injectable, non-immunogenic and effective both in the presence and absence of inhibitors.Haemophilia 12/2014; 21(2). DOI:10.1111/hae.12615 · 2.47 Impact Factor
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ABSTRACT: Hemophilia is the most common inherited severe bleeding disorder. Although the most frequent complication of repeated hemorrhages is a crippling joint disease that begins in childhood, the extent of resultant joint functional impairment varies widely within the hemophilia population. The goal of this exploratory analysis was to examine a national database that collects information on boys with hemophilia, an X-linked severe congenital bleeding disorder, to determine characteristics associated with increased risk of developing limitations in physical functioning as an outcome of recurrent hemorrhages. A standard set of data is collected annually at ∼130 U.S. comprehensive hemophilia treatment centers (HTCs) in a voluntary surveillance program called the Universal Data Collection (UDC) program. Fifteen potential predictors for poor outcomes of physical functioning related to bleeding were examined for boys (aged ≤ 18 years) from 1998 to 2008. Bivariate and multivariate analyses of these predictors performed in 2009 examined associations with self-reported limitation of activities, absenteeism from work or school, and reliance on assistive devices for ambulation and mobility. Multiple characteristics of underlying hemophilia severity and disease chronicity (in particular, increasing age, presence of joint bleeding, and inhibitor antibodies) were independently associated with increased risk of limitations of physical function. Nonwhite race/ethnicity was associated with each of the poorer functional outcomes in bivariate analyses. After controlling for the potential confounding effects of the multiple population characteristics on race, only African-American race was independently associated with activity restrictions, and African-American and Asian/Pacific Island ethnicity with absenteeism. With the exception of indicators of underlying disease severity, only obesity and medical insurance coverage with Medicaid rather than commercial insurance were independently associated with multiple poor outcomes. Interventions focused on eliminating inhibitors, improving outcomes for African-American children with hemophilia, and maintaining healthy body weight are warranted. In addition, strategies are needed to assure adequate insurance coverage for all people with hemophilia to eliminate economic barriers to optimal functional outcomes.American journal of preventive medicine 12/2011; 41(6 Suppl 4):S360-8. DOI:10.1016/j.amepre.2011.09.017 · 4.28 Impact Factor