Peanut allergy-Individual molecules as a key to precision medicine

Establishment of DAS-ELISA and lateral flow immunochromatography for the detection of peanut allergen Ara h 3 after heat-moisture treatment

Peanuts are highly nutritious but pose a significant risk of triggering food allergies. While heat treatment can reduce the allergenicity of many foods, it may also alter their structure, potentially impacting detection results. This study employed double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) and lateral flow immunochromatography (LFIA) to evaluate the allergen Ara h 3 following heat-moisture treatment. DAS-ELISA achieved a detection limit of 39.06 ng/mL, with inter-plate and intra-plate coefficients of variation below 3.05 % and 6.79 %, respectively, and recovery rates ranging from 78.48 % to 90.93 %. LFIA, with a detection limit of 1.6 μg/mL, demonstrated high sensitivity, stability, and no cross-reactivity with other proteins. Both methods were effective in detecting peanut-processed products, with heat-moisture treatment significantly reducing Ara h 3 antigenicity, making them valuable tools for assessing desensitization in food production.

Basophil activation test shows high accuracy in the diagnosis of peanut and tree nut allergy: The Markers of Nut Allergy Study

BACKGROUND

Peanut and tree nut allergies are the most important causes of anaphylaxis. Co-reactivity to more than one nut is frequent, and co-sensitization in the absence of clinical data is often obtained. Confirmatory oral food challenges (OFCs) are inconsistently performed.

OBJECTIVE

To investigate the utility of the basophil activation test (BAT) in diagnosing peanut and tree nut allergies.

METHODS

The Markers Of Nut Allergy Study (MONAS) prospectively enrolled patients aged 0.5-17 years with confirmed peanut and/or tree nut (almond, cashew, hazelnut, pistachio, walnut) allergy or sensitization from Canadian (n = 150) and Austrian (n = 50) tertiary pediatric centers. BAT using %CD63⁺ basophils (SSClow/CCR3pos) as outcome was performed with whole blood samples stimulated with allergen extracts of each nut (0.001-1000 ng/mL protein). BAT results were assessed against confirmed allergic status in a blinded fashion to develop a generalizable statistical model for comparison to extract and marker allergen-specific IgE.

RESULTS

A mixed effect model integrating BAT results for 10 and 100 ng/mL of peanut and individual tree nut extracts was optimal. The area under the ROC curve (AUROC) was 0.98 for peanut, 0.97 for cashew, 0.92 for hazelnut, 0.95 for pistachio, and 0.97 for walnut. The BAT outperformed sIgE testing for peanut or hazelnut and was comparable for walnut (AUROC 0.95, 0.94, 0.92) in a sub-analysis in sensitized patients undergoing OFC.

CONCLUSIONS

Basophil activation test can predict allergic clinical status to peanut and tree nuts in multi-nut-sensitized children and may reduce the need for high-risk OFCs in patients.

Food Allergies: An Example of Translational Research

Food allergies have been rising in prevalence since the 1990s, imposing substantial physical, psychosocial, and economic burdens on affected patients and their families. Until recently, the only therapy for food allergy was strict avoidance of the allergenic food. Recent advances in translational studies, however, have led to insights into allergic sensitization and tolerance. This article provides an overview of cutting-edge research into food allergy and immune tolerance mechanisms utilizing mouse models, human studies, and systems biology approaches. This research is being translated and implemented in the clinical setting to improve diagnosis and reduce food allergy's public health burden.

IgE-Mediated Peanut Allergy: Current and Novel Predictive Biomarkers for Clinical Phenotypes Using Multi-Omics Approaches

Food allergy is a collective term for several immune-mediated responses to food. IgE-mediated food allergy is the best-known subtype. The patients present with a marked diversity of clinical profiles including symptomatic manifestations, threshold reactivity and reaction kinetics. In-vitro predictors of these clinical phenotypes are evasive and considered as knowledge gaps in food allergy diagnosis and risk management. Peanut allergy is a relevant disease model where pioneer discoveries were made in diagnosis, immunotherapy and prevention. This review provides an overview on the immune basis for phenotype variations in peanut-allergic individuals, in the light of future patient stratification along emerging omic-areas. Beyond specific IgE-signatures and basophil reactivity profiles with established correlation to clinical outcome, allergenomics, mass spectrometric resolution of peripheral allergen tracing, might be a fundamental approach to understand disease pathophysiology underlying biomarker discovery. Deep immune phenotyping is thought to reveal differential cell responses but also, gene expression and gene methylation profiles (eg, peanut severity genes) are promising areas for biomarker research. Finally, the study of microbiome-host interactions with a focus on the immune system modulation might hold the key to understand tissue-specific responses and symptoms. The immune mechanism underlying acute food-allergic events remains elusive until today. Deciphering this immunological response shall enable to identify novel biomarker for stratification of patients into reaction endotypes. The availability of powerful multi-omics technologies, together with integrated data analysis, network-based approaches and unbiased machine learning holds out the prospect of providing clinically useful biomarkers or biomarker signatures being predictive for reaction phenotypes.

Advances and novel developments in mechanisms of allergic inflammation

In the past decade, research in the molecular and cellular underpinnings of basic and clinical immunology has significantly advanced our understanding of allergic disorders, allowing scientists and clinicians to diagnose and treat disorders such as asthma, allergic and nonallergic rhinitis, and food allergy. In this review, we discuss several significant recent developments in basic and clinical research as well as important future research directions in allergic inflammation. Certain key regulatory cytokines, genes and molecules have recently been shown to play key roles in allergic disorders. For example, interleukin-33 (IL-33) plays an important role in refractory disorders such as asthma, allergic rhinitis and food allergy, mainly by inducing T helper (Th) 2 immune responses and clinical trials with IL-33 inhibitors are underway in food allergy. We discuss interleukin 4 receptor pathways, which recently have been shown to play a critical role among the allergic inflammatory pathways that drive allergic disorders and pathogenesis. Further, the cytokine thymic stromal lymphopoietin (TSLP) has recently been shown as a factor in maintaining immune homeostasis and regulating type 2 inflammatory responses at mucosal barriers in allergic inflammation and targeting TSLP-mediated signalling is considered an attractive therapeutic strategy. In addition, new findings establish an important T cell-intrinsic role of mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1) proteolytic activity in the suppression of autoimmune responses. We have seen how mutations in the filaggrin gene are a significant risk factor for allergic diseases such as atopic dermatitis, asthma, allergic rhinitis, food allergy, contact allergy, and hand eczema. We are only beginning to understand the mechanisms by which the human microbiota may be regulating the immune system, and how sudden changes in the composition of the microbiota may have profound effects, linked with an increased risk of developing chronic inflammatory disorders, including allergies. New research has shown the important but complex role monocytes play in disorders such as food allergies. Finally, we discuss some of the new directions of research in this area, particularly the important use of biologicals in oral immunotherapy, advances in gene therapy, multifood therapy, novel diagnostics in diagnosing allergic disorders and the central role that omics play in creating molecular signatures and biomarkers of allergic disorders such as food allergy. Such exciting new developments and advances have significantly moved forth our ability to understand the mechanisms underlying allergic diseases for improved patient care.

Recent developments and highlights in food allergy

The achievement of long-lasting, safe treatments for food allergy is dependent on the understanding of the immunological basis of food allergy. Accurate diagnosis is essential for management. In recent years, data from oral food challenges have revealed that routine allergy testing is poor at predicting clinical allergy for tree nuts, almonds in particular. More advanced antigen-based tests including component-resolved diagnostics and epitope reactivity may lead to more accurate diagnosis and selection of therapeutic intervention. Additional diagnostic accuracy may come from cellular tests such as the basophil activation test or mast cell approaches. In the context of clinical trials, cellular tests have revealed specific T-cell and B-cell populations that are more abundant in food-allergic individuals with distinct mechanistic features. Awareness of clinical markers, such as the ability to eat baked forms of milk and egg, continues to inform the understanding of natural tolerance development. Mouse models have allowed for investigation into multiple mechanisms of food allergy including modification of epithelial metabolism, and the induction of regulatory cell subsets and the microbiome. Increasing numbers of children who underwent food immunotherapy enlarged the body of evidence on mechanisms and predictors of treatment success. Experimental immunological markers in conjunction with clinical determinants such as lower age and lower initial specific IgE appear to be of benefit. More research on the optimal dose, preparation, and route of application integrating a high-level safety and efficacy is demanded. Alternatively, biologics blocking TSLP, IL-33, IL-4 and IL-13, or IgE may help to achieve that.

Future research trends in understanding the mechanisms underlying allergic diseases for improved patient care

The specialties of allergy and clinical immunology have entered the era of precision medicine with the stratification of diseases into distinct disease subsets, specific diagnoses, and targeted treatment options, including biologicals and small molecules. This article reviews recent developments in research and patient care and future trends in the discipline. The section on basic mechanisms of allergic diseases summarizes the current status and defines research needs in structural biology, type 2 inflammation, immune tolerance, neuroimmune mechanisms, role of the microbiome and diet, environmental factors, and respiratory viral infections. In the section on diagnostic challenges, clinical trials, precision medicine and immune monitoring of allergic diseases, asthma, allergic and nonallergic rhinitis, and new approaches to the diagnosis and treatment of drug hypersensitivity reactions are discussed in further detail. In the third section, unmet needs and future research areas for the treatment of allergic diseases are highlighted with topics on food allergy, biologics, small molecules, and novel therapeutic concepts in allergen‐specific immunotherapy for airway disease. Unknowns and future research needs are discussed at the end of each subsection.

The functional biology of peanut allergens and possible links to their allergenicity

Peanut is one of the most common food triggers of fatal anaphylaxis worldwide although peanut allergy affects only 1%-2% of the general population. Peanuts are the source of highly potent allergenic proteins. It is emerging that the allergenicity of certain proteins is linked to their biological function. Peanut is an unusual crop in that it flowers aboveground but produces its seed-containing pods underground. This so-called geocarpic fruiting habit exposes pods and seeds during their development to soilborne pathogens and pests. Pest damage can also open routes of entry for opportunistic fungi such as Aspergillus. Although seed proteins have primary functions in nutrient reservoirs, lipid storage bodies, or the cytoskeleton, they have also evolved to act as part of the plant's defense system to enhance fitness and survival of the species. When interacting with pathogens or pests, these proteins modify and damage cells' membranes, interact with immune receptors, and modulate signaling pathways. Moreover, following exposure, the immune system of predisposed individuals reacts to these proteins with the production of specific IgE. This review explores the evolutionary biology of peanut and its seed proteins and highlights possible links between the proteins' biological function and their allergenicity.