Food Allergy

An expanded framework for Swab Touch Spray-Mass Spectrometry towards the detection of allergenic protein residues on food preparation surfaces

BACKGROUND

Ambient Mass Spectrometry (AMS) encompasses a group of techniques that have emerged as powerful strategies for direct, in-situ and high-throughput analysis, also in compliance with the principles of green analytical chemistry. Swab Touch Spray-Mass Spectrometry (Swab TS-MS) is a home-made AMS technique that involves the use of a medical swab as sampling tool and electrospray probe. To date, Swab TS-MS has been applied only for the analysis of small molecules, especially in forensic and medical fields, leaving the analysis of peptides and proteins still unexplored.

RESULTS

In the present study, the application framework of Swab TS-MS was expanded towards the detection of proteins, focusing on residues of allergenic ingredients as contaminants of food preparation surfaces. Lysozyme from chicken egg white was selected as case study of allergenic protein. Since none of the experimental conditions explored allowed the detection of intact lysozyme, a bottom-up procedure based on tryptic digestion for lysozyme detection by Swab TS-MS, operating in MS/high resolution (HR)MS tandem mode, was investigated. In parallel, liquid chromatography-tandem mass spectrometry was used to develop and characterize an in-situ digestion/swabbing strategy, allowing to reach a LOD value of 0.003 μg/cm2 of egg white powder consistent with that of lateral flow immunoassay technique. Finally, the developed in-situ digestion/swabbing procedure was coupled to the Swab TS-MS/HRMS method, permitting the direct analysis of egg white powder residues on stainless steel surfaces, reaching a LOD of 68 μg/cm2 egg white powder, corresponding to 2.4 μg/cm2 of lysozyme.

SIGNIFICANCE

This study should be intended as a first step for the application of Swab TS-MS technique in protein analysis: the developed in-situ digestion and sampling strategy suitable for Swab TS-MS direct analysis of food allergen has a valuable impact towards the availability of MS-based multiplexed detection tool useful for the development of efficient surface cleaning procedures.

Genome-Wide Association Study Reveals a Causal Relationship Between Allergic Rhinitis and Hazelnut Allergy

BACKGROUND

Little is known about the genetics of food allergy (FA) to various allergens and the heterogeneity of FA in adults.

OBJECTIVE

We aimed to investigate genetic susceptibility to FA in an adult population and to assess the association between secondary FA and allergic rhinitis (AR).

METHODS

FA and allergen-specific FA were defined based on in-depth questionnaires and a previously published FA algorithm in the Lifelines. We performed a series of genome-wide association studies (GWAS) on FA and nine allergen-specific (e.g., hazelnut) FA in 21,353 adults in Lifelines. Single nucleotide polymorphisms (SNPs) (p < 1E-5) were replicated in a second independent set of 15,518 adults participating in the Lifelines followed by meta-analysis of the results of the two datasets. We subsequently investigated the causal relationship of AR to FA using Mendelian randomization (MR) analysis.

RESULTS

We observed co-occurrence of tree nuts and apple FA, with over 80% of this group also reporting AR. After meta-analysis, we identified one genome-wide significant locus near HLA-DPA1 associated with self-reported hazelnut allergy (hazelnutFA), of which the top SNP is rs5025825 (p = 2.51E-9, OR = 1.43). Two-sample MR indicated that AR is a significant causal risk factor for hazelnutFA (p-IVW = 5.27E-10, β = 5.90, p-pleiotropy = 0.46).

CONCLUSION

Our questionnaire enabled a large GWAS on self-reported FA in Dutch adults. We report one novel locus in the human leukocyte antigens (HLA) region associated with hazelnutFA, implying an association with antigen recognition. Our findings genetically link secondary FA to AR in adults.

Differences in the Course, Diagnosis, and Treatment of Food Allergies Depending on Age-Comparison of Children and Adults

Food allergy (FA) has become a common global public health issue, with a growing prevalence in the modern world and a significant impact on the lives of patients, their families, and caregivers. It affects every area of life and is associated with elevated costs. Food allergy is an adverse immune reaction that occurs in response to a given food. The symptoms vary from mild to severe and can lead to anaphylaxis. This is why it is important to focus on the factors influencing the occurrence of food allergies, specific diagnostic methods, effective therapies, and especially prevention. Recently, many guidelines have emphasized the impact of introducing specific foods into a child's diet at an early age in order to prevent food allergies. Childhood allergies vary with age. In infants, the most common allergy is to cow's milk. Later in life, peanut allergy is more frequently diagnosed. Numerous common childhood allergies can be outgrown by adulthood. Adults can also develop new IgE-mediated FA. The gold standard for diagnosis is the oral provocation test. Skin prick tests, specific IgE measurements, and component-resolved diagnostic techniques are helpful in the diagnosis. Multiple different approaches are being tried as possible treatments, such as immunotherapy or monoclonal antibodies. This article focuses on the prevention and quality of life of allergic patients. This article aims to systematize the latest knowledge and highlight the differences between food allergies in pediatric and adult populations.

Salivary interleukin-17A and interferon-γ levels are elevated in children with food allergies in China

Introduction

Food allergies have a substantial impact on patient health, but their mechanisms are poorly understood, and strategies for diagnosing, preventing, and treating food allergies are not optimal. This study explored the levels of and relationship between IL-17A and IFN-γ in the saliva of children with food allergies, which will form the basis for further mechanistic discoveries as well as prevention and treatment measures for food allergies.

Methods

A case-control study with 1:1 matching was designed. Based on the inclusion criteria, 20 case-control pairs were selected from patients at the Skin and Allergy Clinic and children of employees. IL-17A and IFN-γ levels in saliva were measured with a Luminex 200 instrument. A general linear model was used to analyze whether the salivary IL-17A and IFN-γ levels in the food allergy group differed from those in the control group.

Results

The general linear model showed a significant main effect of group (allergy vs. healthy) on the levels of IL-17A and IFN-γ. The mean IL-17A level (0.97 ± 0.09 pg/ml) in the food allergy group was higher than that in the healthy group (0.69 ± 0.09 pg/ml). The mean IFN-γ level (3.0 ± 0.43 pg/ml) in the food allergy group was significantly higher than that in the healthy group (1.38 ± 0.43 pg/ml). IL-17A levels were significantly positively related to IFN-γ levels in children with food allergies (r=0.79) and in healthy children (r=0.98).

Discussion

The salivary IL-17A and IFN-γ levels in children with food allergies were higher than those in healthy children. This finding provides a basis for research on new methods of diagnosing food allergies and measuring the effectiveness of treatment.

Update on In Vitro Diagnostic Tools and Treatments for Food Allergies

Food allergy (FA) is an adverse immunological reaction to a specific food that can trigger a wide range of symptoms from mild to life-threatening. This adverse reaction is caused by different immunological mechanisms, such as IgE-mediated, non-IgE-mediated and mixed IgE-mediated reactions. Its epidemiology has had a significant increase in the last decade, more so in developed countries. It is estimated that approximately 2 to 10% of the world's population has FA and this number appears to be increasing and also affecting more children. The diagnosis can be complex and requires the combination of different tests to establish an accurate diagnosis. However, the treatment of FA is based on avoiding the intake of the specific allergenic food, thus being very difficult at times and also controlling the symptoms in case of accidental exposure. Currently, there are other immunomodulatory treatments such as specific allergen immunotherapy or more innovative treatments that can induce a tolerance response. It is important to mention that research in this field is ongoing and clinical trials are underway to assess the safety and efficacy of these different immunotherapy approaches, new treatment pathways are being used to target and promote the tolerance response. In this review, we describe the new in vitro diagnostic tools and therapeutic treatments to show the latest advances in FA management. We conclude that although significant advances have been made to improve therapies and diagnostic tools for FA, there is an urgent need to standardize both so that, in their totality, they help to improve the management of FA.