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Margaretha A. Faber

Bio: Margaretha A. Faber is an academic researcher from University of Antwerp. The author has contributed to research in topics: Immunoglobulin E & Basophil activation. The author has an hindex of 21, co-authored 79 publications receiving 1088 citations. Previous affiliations of Margaretha A. Faber include Health Science University & World Allergy Organization.

Papers published on a yearly basis

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Journal ArticleDOI
01 Jun 2017-Allergy
TL;DR: This review summarizes the current knowledge about major and minor allergens related to shellfish allergy and identifies invertebrate tropomyosin, arginine kinase, myosin light chain, sarcoplasmic calcium‐binding protein, and hemocyanin as the most relevant.
Abstract: IgE-mediated shellfish allergy constitutes an important cause of food-related adverse reactions. Shellfish are classified into mollusks and crustaceans, the latter belonging to the class of arthropoda. Among crustaceans, shrimps are the most predominant cause of allergic reactions and thus more extensively studied. Several major and minor allergens have been identified and cloned. Among them, invertebrate tropomyosin, arginine kinase, myosin light chain, sarcoplasmic calcium-binding protein, and hemocyanin are the most relevant. This review summarizes our current knowledge about these allergens.

112 citations

Journal ArticleDOI
TL;DR: The potential and limitations of quantification of sIgE, mediator release, and BAT in anesthesia-related IHRs, a literature search was conducted using the key words allergy, basophil activation, CD63, CD203c, diagnosis, drugs, hypersensitivity, flow cytometry, MRGPRX2, specific IgE antibodies, leukotrienes, histamine, and tryptase.

58 citations

Journal ArticleDOI
TL;DR: Wasp venom allergy is a potentially life‐threatening condition with serious consequences of diagnostic error and needs to be treated with care.
Abstract: SummaryBackground Wasp venom allergy is a potentially life-threatening condition with serious consequences of diagnostic error. Objective To assess whether component-resolved diagnosis, using non-glycosylated recombinant allergen components from yellow jacket can add to the diagnosis of wasp venom allergy. Methods In total, 148 patients with a wasp (yellow jacket) allergy were included, 91 with unequivocal tests, 26 with double positivity of serum-specific IgE (sIgE) to both venoms, 21 with discrepant sIgE and skin test results and finally 10 having their diagnosis only confirmed by basophil activation test (negative sIgE and skin test results). Specific IgE to recombinant species-specific allergen components Ves v 1 and Ves v 5 from yellow jacket, Api m 1 from honeybee and Ves v 5 complemented wasp venom were tested by ImmunoCAP. Results Overall, combined use of sIgE to rVes v 1 and rVes v 5 allowed correct diagnosis in 139 of the 148 patients (94%) and rApi m 1 was demonstrable in only one patient. Supplementing the traditional yellow jacket allergosorbent with rVes v 5 allowed to correctly diagnose wasp allergy in patients sensitized to Ves v 5 but demonstrating a negative sIgE to wasp venom. Conclusion Component-resolved diagnoses with the wasp-specific recombinant allergen components Ves v 1 and Ves v 5 is a reliable method to diagnose yellow jacket allergy and can help to take out the sting of difficult cases. However, as the number of patients with doubt after conventional tests is small, larger collaborative studies are needed to draw more definitive conclusions. Whether the rVes v 5 supplemented yellow jacket allergosorbent constitutes an asset in the diagnostic management of wasp venom allergy remains to be further established.

57 citations

Journal ArticleDOI
TL;DR: The first identification of a TPSAB1 quintuplication manifest in a highly symptomatic patient with clonal mast cell disease is reported, clarifying the literature, and suggesting the potential for a link between mastocytosis and hereditary alpha tryptasemia.
Abstract: To the Editor Hereditary alpha tryptasemia is caused by increased TPSAB1 copy number on a single allele, encoding additional copies of alpha-tryptase [1]. This genetic trait is inherited in an autosomal dominant manner, and affected individuals display elevated basal serum tryptase (BST; > 8 ng/mL). While clonal mast cell disease has not been reported among patients with this trait previously, a number of individuals present with symptoms frequently reported by patients with clonal disease including functional gastrointestinal and pain symptoms and cutaneous flushing and pruritus. Among those affected, BST and these clinical symptoms have been observed to follow a gene-dosage relationship, with increased TPSAB1 copy number leading to greater symptom expressivity and higher BST; however, only duplications and triplications have previously been identified [2]. Moreover, features suggestive of mast cell compartment disruption, including increased mast cell number and abnormal spindle-shaped morphology (> 25%) in bone marrow, have also been observed in patients with hereditary alpha tryptasemia [3]. Herein, we report the first identification of a TPSAB1 quintuplication manifest in a highly symptomatic patient with clonal mast cell disease, clarifying the literature, and suggesting the potential for a link between mastocytosis and hereditary alpha tryptasemia. A three-generation family of Belgian ancestry was recently reported with dominantly inherited BSTelevations of unknown etiology, associated with clinical and biochemical evidence of mast cell mediator release; 4/7 individuals presented with recurrent episodic severe abdominal cramping and diarrhea concomitant with transient increases of serum tryptase above elevated baseline levels (> 1.2 x BST plus ≥ 2 ng/mL); family members with normal BST were asymptomatic [4]. All five adults with elevated BST underwent bone marrow and gastrointestinal biopsies, and bone marrow was screened for the presence of c.2447A>T (p.D816V) KIT as described in the Online Supplement. No morphologic or immunophenotypic evidence of abnormal mast cells was found. However, in a significantly affected individual with elevated BST (II.3), a 22-year-old male who was also identified as having mild hepatosplenomegaly (liver 15.5 cm, spleen 12.2 cm), a somatic c.2447A>T (p.D816V) KIT mutation was detected (Fig. 1a; Fig. S1). Despite harboring this mutation—which is present in 90% of individuals with indolent systemic mastocytosis (ISM) and is a minor criterion for the clinical diagnosis of ISM—the patient did not meet criteria for ISM (Table S1). However, this presentation may constitute a pre-diagnostic phase of ISM [5], or represent a splenic variant of disease as has been described [6]. Affected individuals in this family have been treated with anti-H1 and anti-H2 antihistamines as well as oral sodium cromolyn and cessation of these treatments has resulted in relapses of symptoms. Using our droplet digital PCR-based Capsule Summary Clonal mast cell disease can be associated with hereditary alpha tryptasemia.

55 citations

Journal ArticleDOI
TL;DR: Immunoglubulin E antibody‐mediated allergic reactions to opioids are rare and difficult to document correctly.
Abstract: Background: Immunoglubulin E antibody-mediated allergic reactions to opioids are rare and difficult to document correctly Objective: Assessment of the basophil activation test in the diagnosis of IgE-mediated allergy to the antitussive pholcodine and associated sensitizations to neuromuscular blocking agents (NMBA) Methods: Three patients with a suspected IgE-mediated allergy to pholcodine were investigated using skin tests, quantification of specific IgE, and flow cytometric activation of basophils Results and conclusion: Flow cytometric activation of basophils, with simultaneous analysis of CD63 appearance and median histamine content per cell, is the only technique capable to correctly document pholcodine allergy The negative predictive value of basophil activation tests might help to elucidate on the controversial putative cross-reactivity between pholcodine and NMBA V C 2013 International Clinical Cytometry Society

54 citations


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TL;DR: To evaluate strategies of early peanut consumption or avoidance for prevention of peanut allergy in patients at risk, 640 patients from severe eczema, egg allergy, or both were evaluated over a 60-month period.
Abstract: G Du Toit, G Roberts, PH Sayre N Engl J Med 2015;372:803–813 To evaluate strategies of early peanut consumption or avoidance for prevention of peanut allergy in patients at risk The participants were between 4 and 11 months of age at randomization They suffered from severe eczema, egg allergy, or both A total of 640 patients were evaluated over a 60-month period They were stratified according to their sensitivity to skin testing to peanut extract Those with no measureable wheal were evaluated as not sensitized, those with wheal diameters 1 to 4 mm were considered sensitized, and participants with >4-mm wheal were excluded Participants were randomized to receive an initial supervised feeding …

687 citations

Journal ArticleDOI
TL;DR: The European Academy of Allergy and Clinical Immunology (EAACI) Molecular Allergology User's Guide (MAUG) as mentioned in this paper provides comprehensive information on important allergens and describes the diagnostic options using component-resolved diagnosis (CRD).
Abstract: The availability of allergen molecules ('components') from several protein families has advanced our understanding of immunoglobulin E (IgE)-mediated responses and enabled 'component-resolved diagnosis' (CRD). The European Academy of Allergy and Clinical Immunology (EAACI) Molecular Allergology User's Guide (MAUG) provides comprehensive information on important allergens and describes the diagnostic options using CRD. Part A of the EAACI MAUG introduces allergen molecules, families, composition of extracts, databases, and diagnostic IgE, skin, and basophil tests. Singleplex and multiplex IgE assays with components improve both sensitivity for low-abundance allergens and analytical specificity; IgE to individual allergens can yield information on clinical risks and distinguish cross-reactivity from true primary sensitization. Part B discusses the clinical and molecular aspects of IgE-mediated allergies to foods (including nuts, seeds, legumes, fruits, vegetables, cereal grains, milk, egg, meat, fish, and shellfish), inhalants (pollen, mold spores, mites, and animal dander), and Hymenoptera venom. Diagnostic algorithms and short case histories provide useful information for the clinical workup of allergic individuals targeted for CRD. Part C covers protein families containing ubiquitous, highly cross-reactive panallergens from plant (lipid transfer proteins, polcalcins, PR-10, profilins) and animal sources (lipocalins, parvalbumins, serum albumins, tropomyosins) and explains their diagnostic and clinical utility. Part D lists 100 important allergen molecules. In conclusion, IgE-mediated reactions and allergic diseases, including allergic rhinoconjunctivitis, asthma, food reactions, and insect sting reactions, are discussed from a novel molecular perspective. The EAACI MAUG documents the rapid progression of molecular allergology from basic research to its integration into clinical practice, a quantum leap in the management of allergic patients.

558 citations

Journal ArticleDOI
01 Aug 2006-BMJ

522 citations

Journal ArticleDOI
TL;DR: Understanding mechanisms underlying induction and persistence of tolerance should identify predictive biomarkers of clinical response and discover novel and more effective strategies for immunotherapy.
Abstract: Allergen immunotherapy is effective in patients with IgE-dependent allergic rhinitis and asthma. When immunotherapy is given continuously for 3 years, there is persistent clinical benefit for several years after its discontinuation. This disease-modifying effect is both antigen-specific and antigen-driven. Clinical improvement is accompanied by decreases in numbers of effector cells in target organs, including mast cells, basophils, eosinophils, and type 2 innate lymphoid cells. Immunotherapy results in the production of blocking IgG/IgG 4 antibodies that can inhibit IgE-dependent activation mediated through both high-affinity IgE receptors (FceRI) on mast cells and basophils and low-affinity IgE receptors (FceRII) on B cells. Suppression of T H 2 immunity can occur as a consequence of either deletion or anergy of antigen-specific T cells; induction of antigen-specific regulatory T cells; or immune deviation in favor of T H 1 responses. It is not clear whether the altered long-term memory resides within the T-cell or the B-cell compartment. Recent data highlight the role of IL-10–producing regulatory B cells and "protective" antibodies that likely contribute to long-term tolerance. Understanding mechanisms underlying induction and persistence of tolerance should identify predictive biomarkers of clinical response and discover novel and more effective strategies for immunotherapy.

304 citations

Journal ArticleDOI
01 Nov 2015-Allergy
TL;DR: The nature of basophil activation as an ex vivo challenge makes it a multifaceted and promising tool for the allergist, and it ought to precede challenge testing.
Abstract: The basophil activation test (BAT) has become a pervasive test for allergic response through the development of flow cytometry, discovery of activation markers such as CD63 and unique markers identifying basophil granulocytes. Basophil activation test measures basophil response to allergen cross-linking IgE on between 150 and 2000 basophil granulocytes in <0.1 ml fresh blood. Dichotomous activation is assessed as the fraction of reacting basophils. In addition to clinical history, skin prick test, and specific IgE determination, BAT can be a part of the diagnostic evaluation of patients with food-, insect venom-, and drug allergy and chronic urticaria. It may be helpful in determining the clinically relevant allergen. Basophil sensitivity may be used to monitor patients on allergen immunotherapy, anti-IgE treatment or in the natural resolution of allergy. Basophil activation test may use fewer resources and be more reproducible than challenge testing. As it is less stressful for the patient and avoids severe allergic reactions, BAT ought to precede challenge testing. An important next step is to standardize BAT and make it available in diagnostic laboratories. The nature of basophil activation as an ex vivo challenge makes it a multifaceted and promising tool for the allergist. In this EAACI task force position paper, we provide an overview of the practical and technical details as well as the clinical utility of BAT in diagnosis and management of allergic diseases.

288 citations