Multi-omics Endotyping of Food-allergic Patients For Advanced Biomarker Discovery

Background. Food allergies are a global burden causing severe clinical reactions including fatal anaphylaxis. Peanuts are counted among the most potent elicitors involved in IgE-mediated food allergies. Peanut allergy is a relevant disease model because of its steadily increasing prevalence and poor prognosis of outgrowth. Clinical phenotypes of peanut-allergic patients are highly variable. Patients might experience variable medical symptoms (organs, severity, delay), threshold and cross-reactivity levels suggest. Reliable in-vitro biomarker allowing to predict clinical reactivity and score the patients into reaction endotypes are missing.

Most important peanut allergens have been studied as to their biomolecular properties biological activities and allergenic potency. The pronounced protein stability of potent peanut allergens is thought to contribute to the molecules' allergenicity. Upon ingestion, food proteins are broken down, entering the human body via epithelial surfaces. The identity and the fate of immunologically active allergen peptides after epithelial absorption remains elusive. Beyond this, complex immune cascades take place during acute allergic episodes. How immune cells, such as lymphocytes, orchestrate in patients with different clinical outcomes (e.g., sensitivity, severity) still remains to be solved. Several studies have shown that the composition and the diversity of the gut microbiota is relevant for shaping the immune response to food proteins. The functional interaction between host and gut microbiome, in the context of symptom development and phenotypic variations, is unexplored until today.

Aims. This project aims to explore putative biomarkers at various levels, at the level of IgE-profiles, at the level of allergen absorption, at the level of scored basophil reactivity, at the level of immune phenotypes and at the level of gut microbiome-host interactions, by applying multiple omics technologies.

Partners. The Luxembourg Institute of Health (LIH), Department of Infection and Immunity (DII; head Prof. M. Ollert) has the scientific project lead (Principal Investigator Dr. A. Kuehn). Main clinical partners are Dr. F. Codreanu-Morel from the National Unit of Immunology-Allergology, Centre Hospitalier (CHL), Luxembourg, as well as Prof. C. Bindslev-Jensen from Odense Research Centre for Anaphylaxis (ORCA), Denmark. Partner for the execution of the clinical part will be the Clinical and Epidemiological Investigation Center (CIEC, LIH) headed by Dr. M. Gantenbein. The Integrated Biobank of Luxembourg (IBBL) will prepare and store clinical samples until use. Clinical samples (blood, sera, plasma) will be analyzed at DII, LIH. Stool samples will be investigated with the help of Prof. P. Wilmes from the Systems Ecology research group, Luxembourg Centre for Systems Biomedicine (LCSB).

Project implementation. Food challenges (OFC) to peanut will be proceeded according to official guidelines (European Academy of Allergy and Clinical Immunology, EAACI). Healthy controls (N=10) will be split, half will receive a single food dose of up to 100 g of roasted peanuts (open OFC) and the other half will be tested with up to 5 incremental doses (double-blind placebo-controlled OFC) using the same doses as for allergic patients. For single-dose OFC, blood samples from controls will be taken before the OFC and at 30 minutes, at 60 minutes and at 120 minutes. Controls receiving 5 incremental allergen doses will be subjected to blood sampling before the beginning of the OFC and 1 h after the end of the challenge. As a further control arm in the study, allergenic food from animal origin will be used in OFC. Further healthy controls (N=10) will receive either a single food dose of up to 200 g of cooked fish (open OFC) and the other half will be tested with up to 5 incremental doses (double-blind placebo-controlled OFC). Doses in a range of 10 mg to 100 g of fish will be selected for the blinded OFC with controls.