Projects

Abstract

The risk of anaphylaxis in primary mast cell disorders (PMCDs) and hereditary alpha tryptasemia (H?T) is only partially determined by the mast cell (MC) burden. The overarching hypothesis of this mandate is that the risk of anaphylaxis in PMCDs and H?T is related to an aberrant MC behavior and relates to an imbalance between activating and inhibitory signals culminating in uncontrolled excessive degranulation of these anaphylaxis effector cells. Research conducted during the previous mandate led to the conclusion that the expression of the high affinity receptor for IgE antibodies (Fc?RI) on MCs, but not the quantitative expression of the mas-related G protein coupled receptor X2 (MRGPRX2) nor the phenotype and function of basophil, play a crucial role in determining the risk of wasp venom anaphylaxis in patients with non-advanced PMCDs. Moreover, our previous studies highlight that, for patients with anaphylaxis, clinical and biochemical predictors of PMCDs are suboptimal. Finally, the association between H?T, morphological abnormal MCs, and MC mediator-related symptoms deserve further investigation. During this mandate we aim at expanding study on phenotypic and behavior of individual MCs and integrate with transcriptome and metabolome profiling from phenotypically different patients. The goal is the identification of specific biomarkers able at discriminating in patients with PMCDs phenotypes with and without anaphylaxis.

Researcher(s)

• Promoter: Sabato Vito
• Fellow: Sabato Vito

Research team(s)

• Immunology

Project type(s)

• Research Project

Abstract

Increasing lines of evidence indicate that mast cells (MC) degranulation from off-target occupation of the Mas-related G protein coupled receptor X2 (MRGPRX2) constitutes a novel endotype of IgE/FcεRI (high affinity receptor for IgE) -independent drug anaphylaxis. However, most of the data have been gathered in mice or in malignant mast cell lines. In contrast to MC, MRPGPRX2 is barely expressed on basophils membrane but quickly upregulated after conditioning. Here we propose exploration of a mixed model based upon cultured human mast cells and human basophils aiming at deciphering MRGRPX2 agonism and antagonims in drug anaphylaxis.

Researcher(s)

• Promoter: Sabato Vito
• Co-promoter: Ebo Didier
• Co-promoter: Hagendorens Margo
• Fellow: Van der Poorten Marie-Line

Research team(s)

• Immunology

Project type(s)

• Research Project

Abstract

Drug hypersensitivity constitutes a significant health problem with serious consequences of both mis- and overdiagnosis. nfortunately, correct diagnosis of drug hypersensitivity can pose significant challenges, mainly because of our knowledge gaps in the molecular and pathophysiological processes underlying immediate and non-immediate drug hypersensitivity reactions but also, most importantly, because of the unavailability of reliable in vitro tests and uncertainties associated with skin testing 1-3. This "proof-of-concept project" is an apex of our ongoing overarching research on the cellular processes, pathophysiology and diagnosis of immediate drug hypersensitivity reactions resulting from mast cell and basophil degranulation 1-30. Likely, this project will deepen our insights and shift paradigms in the mechanisms that govern mast cell degranulation finally culminating in immediate drug hypersensitivity reactions. However, our proposal primarily focuses on i) the confirmation of our innovative MAT (mast cell activation test) to be a performant diagnostic and ii) to expand capacity of our service platform to offer these tests to colleagues and industry. With respect to the valorisation, this POC-proposal should promote our services and offering our MAT (amongst other diagnostics) to more colleagues and industry. Today, our laboratory has already created a restricted service platform. In other words, this POC-project will not restrict to confirmation of the MAT, but will also invest, via several initiatives, in the expansion and promotion of our services (inter)nationally, application for a full patent, and in the set-up of a business model. In this context, communication of the data, analyses of demands and market studies are critical. Clearly, the potential of the MAT, which we already filed a priority application for and necessitates only patients' sera, is broad. Moreover, preliminary results from our market analysis, and the potential of additional indications, could result in industrial interest and the creation of a spin-off.

Researcher(s)

• Promoter: Ebo Didier
• Co-promoter: Sabato Vito

Research team(s)

• Immunology

Project type(s)

• Research Project

Abstract

Unverified and allergies to penicillins have developed into an epidemic with unacceptable medical and financial consequences. For over two decades numerous efforts have been undertaken to fight this scourge and to promote judicious diagnosis to reduce erroneous avoidance and unnecessary substitutions with less effective, more toxic and costly broad spectrum second-line non-betalactam antibiotics carrying the potential of the emergence of organism resistance and secondary complications. However, old habits die hard and continuous efforts are required to convince patients and their physicians of the consequences of these false allegations and to encourage implementation of correct management protocols. In this project we primarily aim at i) mapping out the prevalence of spurious and genuine penicillin allergy, ii) optimizing diagnostic management of betlactam allergies according to the individual allergy risk status including resolving the conundrum of cross-reactivity between penicillin and other belactams and iii) evaluate the cost-effectiveness of delabelling spurious "penicillin allergy" in unselected or selected populations. Altogether, our data should facilitate introduction of a cost-effective diagnostic and therapeutic algorithms without jeopardizing health of our patients and benefiting antibiotic stewardship.

Researcher(s)

• Promoter: Sabato Vito
• Co-promoter: Hagendorens Margo

Research team(s)

• Immunology

Project type(s)

• Research Project

Abstract

Anaphylaxis is a potentially life-threatening generalized reaction in which degranulation of basophils and mast cells (MC) is critical. Anaphylaxis can result from allergen that cross-links specific IgE bound to the membrane of the effector cells. This cross-linking of IgE initiates downstream signalling with release of vasoactive mediators (e.g. histamine), along with preformed proteases and cytokines, and de novo synthesis and secretion of lipid mediators and additional cytokines. However, evidence has accumulated that anaphylaxis can also occur in response to IgEindependent stimuli, including occupation of the Mas-related G protein-coupled receptor MRGPRX2. Although quintessence of these studies appears to indicate off-target occupancy of the MRGPRX2 receptor to constitute a novel non-immune endotype of MC-driven drug anaphylaxis, prudence is called upon interpretation of the findings as data in patients are lacking. We will take advantage of our experience in studying mechanisms governing basophil and mast cell activation/degranulation to unveil the processes after MRGPRX2-related anaphylaxis to drugs. Flow-assisted quadruple analysis of activation markers, inhibition receptors, signalling molecules and mediator release by individual human cells will capture data that are inaccessible in animal models or by traditional techniques requiring homogeneous cell populations and of which results only represent an average of all stimulated cells.

Researcher(s)

• Promoter: De Clerck Luc
• Fellow: Ebo Didier

Research team(s)

• Immunology

Project type(s)

• Research Project

Abstract

IgE-mediated peanut allergy starts with a sensitization phase that is characterized by the production of peanut specific IgE (sIgE) antibodies that can be depicted by peanut immunoassays and/or skin tests. However, the production of these peanut sIgE antibodies is not sufficient for the development of an overt peanut allergy. Actually, many subjects with detectable peanut sIgE antibodies in their serum and/or positive skin test response to peanut do not exhibit clinical manifestations when consuming this legume. The divergence between allergic sensitization and clinically overt allergy not only poses significant diagnostic difficulties but also constitutes a fundamental gap in our knowledge and insights about the complex mechanisms of food allergy and tolerance. Clearly, in prospect for future therapy, better understanding of the underlying (molecular) mechanisms is needed. In this project I will investigate whether the clinical phenotype of peanut sensitization and allergy results from altered basophil responses to stimulation with peanut. More specifically, I will look for alterations in basophilic expression and/or function of three families of functionally distinctive inhibitory receptors, i.e. CD300a, CD32B and Siglec-7, 8 and 9. Obtaining more fundamental insights in the basophil response, may disclose diagnostic but also potential therapeutic targets that have already shown promising preclinical results for various mast cell and basophil associated conditions.

Researcher(s)

• Promoter: Ebo Didier
• Co-promoter: Hagendorens Margo
• Co-promoter: Sabato Vito
• Fellow: Van Gasse Athina

Research team(s)

• Immunology

Project type(s)

• Research Project

Abstract

Abstract: Role of dendritic cells in alopecia areata Alopecia areata (AA) is an inflammatory skin condition where spot-wise baldness occurs on the scalp. (alopecia totalis) or on the whole body (alopecia universalis). Both the cellular and humoral immune system play a role in this. More specific dendritic cells (DC), which take care of antigen captation and presentation, play a key role. Different treatment options are known; a frequently used therapy is contact immunotherapy with 2,3-diphenylcyclopropenone (DPCP, diphencyprone). The exact mechanism of action is not yet known. With this project, we want to investigate which dendritic cells can be found in human skin, as well which ones play a specific role in the immunopathogenesis of alopecia areata and treatment of it with DPCP. For this we will include twenty alopecia areata patients and a control group. Aim 1: Identification and characterization of DC-subsets in the skin and blood of AA patients. If patients meet the criteria of our research project, a blood sample of 20 ml and two skin biopsies (diameter 3 mm) are taken of the scalp. These samples will be processed using flowcytometry and immunohistochemie to identify the different DC-subsets. As a comparison, the same protocol will be applied in a healthy control group, so we can compare the subsets in healthy persons with AA patients. Aim 2: Effect of DPCP treatment on the different DC subsets. If the treatment works, and new hair growth can be seen, we will repeat the protocol. So a new blood sample and two skin biopsies of the scalp will be taken. Again it will be processed at the laboratory following the same protocol. We want to find out if the number and the phenotype of the DC-subsets has changed.

Researcher(s)

• Promoter: Lambert Julien

Research team(s)

• Immunology

Project type(s)

• Research Project

Abstract

Nonspecific-lipid transfer proteins (ns-LTPs) have increasingly been recognized to constitute a significant cause of plant food allergy. Sensitization to ns-LTPs was predominantly observed in adults and appeared mainly associated with severe generalized reactions. However, we established that in northern Europe sensitization to ns-LTP can also occur in children and that the sensitization profile assessed by quantification of specific IgE antibodies is not predictive for the clinical phenotype. We hypothesize that a more functional approach with basophil activation experiments (BAT) could be of better predictive value to ascertain the clinical relevance of a sensitization to ns-LTP, as basophil activation requires cross-linking of IgE/FcεRI complexes and therefore more closely mirrors the in vivo situation. We aim at deciphering the clinical relevance of a sensitization to two ns-LTP, i.e. Pru p 3 from peach (Prunus persica) and Mal d 3 (Malus domesticus) from apple, by applying basophil activatation experiments, which might enter mainstream diagnostics as an instrument to discriminate between clinical relevant and irrelevant ns-LTP sensitization. Additionally, the functional activity of so-called blocking IgG4 antibodies will be evaluated.

Researcher(s)

• Promoter: Hagendorens Margo

Research team(s)

• Immunology
• Laboratory Experimental Medicine and Pediatrics (LEMP)

Project website

Project type(s)

• Research Project

Abstract

Anaphylaxis, potentially life-threatening, is one of the principal manifestations of systemic mastocytosis. In these patients anaphylaxis can result from IgEdependent and IgE-independent triggering of mast cells and/or basophils. However, the exact reasons for anaphylaxis in systemic mastocytosis remain a fundamental gap in our knowledge. This gap needs to be filled in order to optimize our patients' care and tailor their individual management. Indeed, the total mast cell burden, hitherto best reflected by the serum tryptase level, does not predict the risk of anaphylaxis nor its clinical outcome. Needless to stress that the uncertainties associated to their condition have a severe impact on the quality-of-life of the patient. Our hypothesis is that the occurrence of anaphylaxis in patients with systemic mastocytosis relates to an imbalance in activating and inhibitory pathways in mast cells and basophils, both critical effector cells of anaphylaxis. For this purpose we will first compare the immunophenotype of mast cells and basophils from patients with systemic mastocytosis with and without anaphylaxis. Secondly, we will study the behaviour of individual cells in response to various combinations of activators and inhibitors. As illustrated by our track-record we believe that this application fits into our overarching research. The Antwerp mastocytosis center will guarantee inclusion of the sufficient numbers of patients and healthy controls.

Researcher(s)

• Promoter: Ebo Didier
• Co-promoter: Berneman Zwi
• Fellow: Sabato Vito

Research team(s)

• Immunology

Project type(s)

• Research Project

Abstract

Food allergy constitutes a significant health issue with important cant morbidity and mortality. This multicentric project (AllerScreening) aims at evaluating the reliability of a novel multiplexed IgE binding assay in the diagnosis of various IgE-mediated food allergies.

Researcher(s)

• Promoter: Ebo Didier

Research team(s)

• Immunology

Project type(s)

• Research Project

Abstract

IgE-mediated peanut allergy starts with a sensitization phase that is characterized by the production of peanut specific IgE (sIgE) antibodies that can be depicted by peanut immunoassays and/or skin tests. However, the production of these peanut sIgE antibodies is not sufficient for the development of an overt peanut allergy. Actually, many subjects with detectable peanut sIgE antibodies in their serum and/or positive skin test response to peanut do not exhibit clinical manifestations when consuming this legume. The divergence between allergic sensitization and clinically overt allergy not only poses significant diagnostic difficulties but also constitutes a fundamental gap in our knowledge and insights about the complex mechanisms of food allergy and tolerance. Clearly, in prospect for future therapy, better understanding of the underlying (molecular) mechanisms is needed. In this project I will investigate whether the clinical phenotype of peanut sensitization and allergy results from altered basophil responses to stimulation with peanut. More specifically, I will look for alterations in basophilic expression and/or function of three families of functionally distinctive inhibitory receptors, i.e. CD300a, CD32B and Siglec-7, 8 and 9. Obtaining more fundamental insights in the basophil response, may disclose diagnostic but also potential therapeutic targets that have already shown promising preclinical results for various mast cell and basophil associated conditions.

Researcher(s)

• Promoter: Ebo Didier
• Co-promoter: Hagendorens Margo
• Co-promoter: Sabato Vito
• Fellow: Van Gasse Athina

Research team(s)

• Immunology

Project type(s)

• Research Project