Research Didier Ebo

Abstract

Immediate drug hypersensitivity (IDH) is an important health issue with serious consequences of diagnostic error. Unfortunately diagnosis can be extremely challenging, mainly as mast cell activation leading to IDH reactions can result from IgE-independent mechanisms that remain largely elusive. In this respect, the recently described MRGPRX2 pathway is an attractive mechanistic alternative. However, MRGPPRX2 activation and down-stream signalling remain a complex conundrum with many knowledge gaps and uncertainties about potential risk factors. Unfortunately, research in these domains is not straight forward, as it is mainly hampered by the absence of a technique to unambiguously document a MRGPRX2-mediated IDH reaction. Hence our project, aiming at optimizing our strategy to discriminate between sIgE- and MRGPRX2-mediated IDH reactions, an absolute prerequisite for further investigation of this putative endotype of IDH. In our proposal we will focus on the topography of skin mast cells, enhanced MRGPRX2 expression or functionality by mast cell and genomic or transcriptomic changes as possible explanations of MRGPRX2-mediated IDH reactions. Resolving the IgE vs. MRGPRX2 paradigm could result in more personalized medicine with identification of diagnostic and therapeutic targets for the individual patient.

Researcher(s)

• Promoter: Sabato Vito
• Co-promoter: Ebo Didier
• Fellow: Elst Jessy

Research team(s)

• Immunology

Project type(s)

• Research Project

Abstract

Despite a global distribution of Leishmaniasis and 1.5 to 2 million new cases annually, no effective human vaccines are available and treatment failure with current drugs is on the rise. Mast cells (MCs) are immune sentinels in the skin that are amongst the first to contact the Leishmania parasite following a sand fly bite. These cells play major roles in orchestrating early inflammatory responses, regulating vascular permeability and influencing immunity development in lymph nodes. Despite seminal work in mosquito-transmitted viral diseases, MCs remain underexplored as target cell during parasitic infections. Combining the strengths in immunology, parasitology, transcriptomics and biostatistics, the role of MCs will be assessed in natural Leishmania infection. Combining digital transcriptomic data from large human cohorts and experimental mouse infections, will enable detailed cross-species and multi-tissue insights into MC responses across the whole clinical spectrum of leishmaniasis. Using human MCs derived from progenitors in donor blood, a battery of cellular activation markers and specific silencing of MC gene expression using an in-house, cutting-edge method will enable unprecedented mechanistic insights in the interaction with infectious agents, i.e. Leishmania spp. parasites. This may provide new biomarkers for clinical follow-up as well as novel therapeutic targets that will be explored in the appropriate animal models of leishmaniasis initiated by a sand fly bite.

Researcher(s)

• Promoter: Caljon Guy
• Co-promoter: Ebo Didier

Research team(s)

• Laboratory for Microbiology, Parasitology and Hygiene (LMPH)

Project type(s)

• Research Project

Abstract

The Research Consortium of Excellence Infla-Med combines multidisciplinary expertise of eight research groups from two faculties to perform fundamental and translational research on inflammation, including: inflammatory gastrointestinal, cardiovascular, lung and kidney disorders, sepsis and allergies, as well as parasitic diseases, thereby focusing on specific inflammatory cell populations, including monocytes/macrophages, mast cells, basophils and lymphocytes. The approach of the Infla-Med consortium is twofold. Firstly, fundamental studies are performed to unravel the pathophysiological mechanisms underlying inflammatory conditions in order to enable more rational, targeted and effective intervention strategies. Secondly, Infla-Med aims to identify and validate novel therapeutic targets by screening chemical compounds in early drug discovery studies and by using an extensive platform of in vitro assays and in vivo models. The close collaboration with the Antwerp University Hospital (UZA) creates the opportunity to directly translate and clinically validate experimental findings. Thereby, Infla-Med contributes to two Frontline Research Domains of the University of Antwerp: 'Drug Discovery and Development' and 'Infectious Diseases'. Over the past four years, the multidisciplinary collaborations within Infla-Med have proven to be very successful and productive. By integrating the Infla-Med unique expertise on drug development, in vitro assays and clinically relevant animal models (validated with human samples), significant competitive funding has been acquired at European, national and UAntwerp levels with a success rate of more than 45%, which is far above the (inter)national average. Noteworthy, several Infla-Med projects have also made the transition towards valorization, demonstrating that Infla-Med results obtained from both fundamental research and well-designed preclinical studies can successfully be translated into clinical trials.

Researcher(s)

• Promoter: De Meyer Guido
• Co-promoter: Augustyns Koen
• Co-promoter: Caljon Guy
• Co-promoter: De Meester Ingrid
• Co-promoter: De Winter Benedicte
• Co-promoter: Ebo Didier
• Co-promoter: Heidbuchel Hein
• Co-promoter: Vanden Berghe Tom

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project website

Project type(s)

• Research Project

Abstract

Immediate drug hypersensitivity (IDH) is an important health issue with serious consequences of diagnostic error. Unfortunately diagnosis can be extremely challenging, mainly as mast cell activation leading to IDH reactions can result from IgE-independent mechanisms that remain largely elusive. In this respect, the recently described MRGPRX2 pathway is an attractive mechanistic alternative. However, MRGPPRX2 activation and down-stream signalling remain a complex conundrum with many knowledge gaps and uncertainties about potential risk factors. Unfortunately, research in these domains is not straight forward, as it is mainly hampered by the absence of a technique to unambiguously document a MRGPRX2-mediated IDH reaction. Hence our project, aiming at optimizing our strategy to discriminate between sIgE- and MRGPRX2-mediated IDH reactions, an absolute prerequisite for further investigation of this putative endotype of IDH. In our proposal we will focus on the topography of skin mast cells, enhanced MRGPRX2 expression or functionality by mast cell and genetics as possible explanations of MRGPRX2-mediated IDH reactions. Resolving the IgE vs. MRGPRX2 paradigm could result in more personalized medicine with identification of diagnostic and therapeutic targets for the individual patient.

Researcher(s)

• Promoter: Sabato Vito
• Co-promoter: Ebo Didier
• Fellow: Elst Jessy

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

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

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

Abstract

Dit project kadert in een onderzoeksopdracht tussen enerzijds UA en anderzijds de opdrachtgever. UA levert aan de opdrachtgever de onderzoeksresultaten genoemd in de titel van het project onder de voorwaarden zoals vastgelegd in voorliggend contract.

Researcher(s)

• Promoter: Ebo Didier

Research team(s)

Project type(s)

• Research Project

Abstract

In this project we will continue and extend our explorations of activation markers, inhibitory receptors, signalling molecules and release of mediators such as histamine that was initiated in FWO project 1800609N. Our purpose is to further explore and disentangle the mechanisms that regulate piecemeal and anaphylactic degranulation of basophils and mast cells. In addition we will explore the mechanisms that could account for temporarily (allergenspecific) hypo- and unresponsiveness of both cells.

Researcher(s)

• Promoter: De Clerck Luc
• Fellow: Ebo Didier

Research team(s)

Project type(s)

• Research Project

Abstract

Allergy during anaesthesia is an important health problem with a significant mortality and morbidity. Unfortunately, correct diagnosis is not always straightforward and too frequently overlooked. As a consequence, patients are at unnecessary risk for future life-threatening reactions. Uncertainties associated with skin testing using some of these drugs and the general unavailability of drug-specific immunoglobulin E tests contribute to the frequent failure of adequate investigation and identification of underlying mechanisms, distinguishing IgE-independent from IgE-dependent true anaphylactic reactions in these patients. In this project we would like to explore further the underlying pathomechanisms of immediate type (or IgE-mediated) hypersensitivity reactions that occur during general anaesthesia. For this purpose, we will take opportunity of having developed and validated up-to-date flow cytometric techniques like basophil activation tests and a cellular histamine content assay (HistaFlow®: patented by our laboratory) next to recently developed tools to culture mast cells out of circulating CD34+ progenitor cells. This will enable a combined analysis of surface markers and histamine release after IgE-dependent and IgE-dependent basophil and mast cell activation. Moreover, by having set in place a reference centre with highest throughput of patients in Belgium, it is anticipated that these experiments not only might culminate in the development of novel diagnostic tests to document drug hypersensitivity reactions, but also might help to define save anaesthetic alternatives.

Researcher(s)

• Promoter: Ebo Didier
• Co-promoter: De Clerck Luc
• Fellow: Uyttebroek Astrid

Research team(s)

Project type(s)

• Research Project

Abstract

Despite the high efficacy of allergen-specific immunotherapy, little is known about the mechanisms leading to suppression of basophils and mast cells, which are responsible for the allergic reaction. Therefore, we will assess whether CD300a might be involved in succesfull allergen-specific immunotherapy. It is anticipated that immunotherapy might alter the basophilic and mast cell expression of this receptor, thereby rendering these cells less vulnerable for activation. For this purpose we will apply our recently patented flow cytometric technique that allows a triple analysis of phenotype, signal transduction and histamine release on a single cell level.

Researcher(s)

• Promoter: Ebo Didier
• Fellow: Sabato Vito

Research team(s)

Project type(s)

• Research Project

Abstract

Dendritic cells (DCs) are central mediators that keep the balance between immunity to foreign antigens and immune tolerance to self-proteins. Disruption of this balance may lead to disease. We aim to unravel the role of DCs in T-helper (Th)1/Th17-mediated immune diseases (including inflammatory bowel disease, multiple sclerosis, cardiovascular disease and rheumatoid arthritis), with the purpose to design novel DC-targeted therapeutic strategies.

Researcher(s)

• Promoter: Vrints Christiaan
• Co-promoter: Berneman Zwi
• Co-promoter: De Winter Benedicte
• Co-promoter: Ebo Didier
• Co-promoter: Schrijvers Dorien

Research team(s)

Project type(s)

• Research Project

Abstract

Allergy during anaesthesia is an important health problem with a significant mortality and morbidity. Unfortunately, correct diagnosis is not always straightforward and too frequently overlooked. Thereby placing the patients at unnecessary risk for future life-threatening reactions. Uncertainties associated with skin testing with some of these drugs, and the general unavailability of drug-specific immunoglobulin E tests contribute to the frequent failure to adequately investigate and establish underlying mechanisms of reactions by distinguishing IgE-dependent from IgE-independent true anaphylactic reactions in these patients. In this project we would like to further explore the underlying pathomechanisms of immediate type hypersensitivity reactions that occur during general anaesthesia. For this purpose, we will take opportunity of having developed and validated up-to-date flow cytometric techniques like basophil activation tests and a cellular histamine content assay (HistaFlow®: patented by our laboratory) and recently having developed tools to culture mast cells out of circulating CD34+ progenitor cells. This will enable a combined analysis of surface markers and histamine release after IgE-dependent and IgE-dependent basophil and mast cell activation. Moreover, by having set in place a reference centre with high throughput of patients, it is anticipated that these experiments not only might culminate in the development of novel diagnostics tests to document drug hypersensitivity reactions, but also might help to define save anaesthetic alternatives.

Researcher(s)

• Promoter: Ebo Didier
• Fellow: De Witte Liene

Research team(s)

Project type(s)

• Research Project

Abstract

Current project concerns a new generation, user-friendly, high-speed and compact flow cytometric cell sorter, capable of sorting different cell populations simultaneously, based on their intrinsic characteristics. This warrants further biological, molecular-biological and immunological research of sorted and purified cells.

Researcher(s)

• Promoter: Berneman Zwi
• Co-promoter: Ebo Didier
• Co-promoter: Stevens Wim
• Co-promoter: Van Tendeloo Vigor

Research team(s)

Project type(s)

• Research Project

Abstract

The main objective of this project is to develop for selected allergens such an integrated strategy. In such a strategy, quantitative analysis of the target allergen plays a central role. This project will result in an integrated approach for the allergens soy and hazelnut and can be applied to other allergens in the future so that the government and producers will have the tools to control the legislation concerning allergens in a relable way.

Researcher(s)

• Promoter: Stevens Wim
• Co-promoter: Ebo Didier

Research team(s)

Project type(s)

• Research Project

Abstract

Purpose: To expand insights in the signal transduction of individual basophils, ultimately leading to elucidate the early tolerance mechanisms of VIT in basophils.

Researcher(s)

• Promoter: De Clerck Luc
• Co-promoter: Stevens Wim
• Fellow: Ebo Didier

Research team(s)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Ebo Didier
• Co-promoter: Hagendorens Margo
• Co-promoter: Stevens Wim

Research team(s)

Project type(s)

• Research Project

Abstract

The prevalence of allergic diseases is steadily increasing and management is not always straightforward. This project aims to confirm preliminary own observations that flow-assisted quantification of phosphorylated intracellular signal molecules can constitute a significant improvement in diagnosis and treatment of allergy.

Researcher(s)

• Promoter: Ebo Didier

Research team(s)

Project type(s)

• Research Project

Abstract

The primary objective of the project is to investigate and validate the Basophil activation test in the diagnosis of class II food allergy and to identify patients with definite food allergies. Furthermore, the technique will be applied to discriminate between clinically relevant and irrelevant sIgE antibody results.

Researcher(s)

• Promoter: Stevens Wim
• Co-promoter: Ebo Didier
• Co-promoter: Hagendorens Margo

Research team(s)

Project type(s)

• Research Project

Abstract

The main objective of this project is to develop for selected allergens such an integrated strategy. In such a strategy, quantitative analysis of the target allergen plays a central role. This project will result in an integrated approach for the allergens soy and hazelnut and can be applied to other allergens in the future so that the government and producers will have the tools to control the legislation concerning allergens in a relable way.

Researcher(s)

• Promoter: Stevens Wim
• Co-promoter: Ebo Didier

Research team(s)

Project type(s)

• Research Project

Abstract

The purpose of this project is to obtain further insights in the early appearing tolerance mechanisms of antigen specific immunotherapy in wasp anaphylaxis. For this purpose the intracellular signal transduction of basophils of patients treated with wasp venom immunotherapy will be studied.

Researcher(s)

• Promoter: Stevens Wim
• Fellow: Ebo Didier

Research team(s)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Stevens Wim
• Co-promoter: Berneman Zwi
• Co-promoter: De Clerck Luc
• Co-promoter: Ebo Didier
• Co-promoter: Hagendorens Margo
• Co-promoter: Van Tendeloo Vigor

Research team(s)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Ebo Didier
• Promoter: Stevens Wim

Research team(s)

Project type(s)

• Research Project