Food allergens–food safety hazard

Food allergy is a life-threatening chronic condition that substantially impairs quality of life. It constitutes a significant public health problem that affects children and adults and is a considerable burden on health, medical systems and emerging economies. Food allergy is defined as an adverse health effect arising from a specific immune-mediated response that occurs reproducibly on oral exposure to a given food and which can be mediated by food-specific IgE antibodies, by cellular mechanisms or by both. Appropriately managing food allergies has become an issue for the food industry because of the rising number of individuals with food allergies. Current initiatives to support consumers at risk include a recognised standard for manufacturers seeking to eliminate an allergen from their production, and the integration of food allergy into training for food business operators.

Addressing Common Misconceptions in Food Allergy: A Review

Background: Food allergies are common, affecting 1 in 13 school children in the United States and their prevalence is increasing. Many misconceptions exist with regards to food allergy prevention, diagnosis and management. Objective: The main objective of this review is to address misconceptions with regards to food allergies and discuss the optimal, evidence-based approach for patients who carry this diagnosis. Observations: Common misconceptions in terms of food allergy prevention include beliefs that breastfeeding and delayed introduction of allergenic foods prevent the development of food allergies. In terms of diagnosis, statements such as ‘larger skin prick tests or/and higher levels of food-specific IgE can predict the severity of food-induced allergic reactions’, or ‘Tryptase is always elevated in food-induced anaphylaxis’ are inaccurate. Additionally, egg allergy is not a contraindication for receiving the influenza vaccine, food-allergy related fatalities are rare and peanut oral immunotherapy, despite reported benefits, is not a cure for food allergies. Finally, not all infants with eczema will develop food allergies and epinephrine auto-injectors may unfortunately be both unavailable and underused in food-triggered anaphylaxis. Conclusions and relevance: Healthcare professionals must be familiar with recent evidence in the food allergy field and avoid common misunderstandings that may negatively affect prevention, diagnosis and management of this chronic disease.

Food antigen-specific IgE in dogs with suspected food hypersensitivity

Objective Knowledge of cross-reactions in food-sensitive dogs will influence the choice of elimination diets and the long-term management of those patients. The objective of this study was to evaluate food allergen-specific IgE tests of suspected allergic dogs for concurrent positive reactions as possible evidence for cross reactions between allergens. Material and methods Results of serum IgE tests from 760 suspected allergic dogs submitted to 2 laboratories were evaluated statistically. After the tested allergens were grouped by their phylogenetic relationship, odds ratios as well as a sensitivity analysis of the odds ratios were performed to evaluate if concurrent positive IgE results to 2 allergens occurred more often than expected. Results Within related allergen pairs 27% (laboratory 1) and 72% (laboratory 2) of the pairs could be considered as associated. For the unrelated allergen pairs only 6.8% and 10.6% of the analyzed pairs were considered associated respectively. Strong correlations were shown in the group of ruminant allergens, especially beef and lamb, and grain allergens. High rates of concurrent reactions were also detected in the poultry group, especially between chicken and duck, as well as between pork and ruminant allergens, and soy and grain allergens. Conclusion As our results showed not only correlations within related but also between non-related allergens, the possible relevance of carbohydrate moieties as well as panallergens for canine hypersensitivities warrants further study. Further investigations are necessary to distinguish co-sensitization from cross-reactions and determine the clinical relevance of food-specific IgE reactivity. Clinical relevance Due to possible cross reactivity related allergens, especially beef and lamb as well as grain allergens, should not be used for an elimination diet to avoid false results.

Oral Food Challenge

: Oral food challenge (OFC) is the gold standard for diagnosis of IgE-mediated and non-IgE mediated food allergy. It is usually conducted to make diagnosis, to monitor for resolution of a food allergy, or to identify the threshold of responsiveness. Clinical history and lab tests have poor diagnostic accuracy and they are not sufficient to make a strict diagnosis of food allergy. Higher concentrations of food-specific IgE or larger allergy prick skin test wheal sizes correlate with an increased likelihood of a reaction upon ingestion. Several cut-off values, to make a diagnosis of some food allergies (e.g., milk, egg, peanut, etc.) without performing an OFC, have been suggested, but their use is still debated. The oral food challenge should be carried out by experienced physicians in a proper environment equipped for emergency, in order to carefully assess symptoms and signs and correctly manage any possible allergic reaction. This review does not intend to analyse comprehensively all the issues related to the diagnosis of food allergies, but to summarize some practical information on the OFC procedure, as reported in a recent issue by The Expert Review of Food Allergy Committee of Italian Society of Pediatric Allergy and Immunology (SIAIP)

Food-Specific IgE and IgG Antibodies in Patients With Chronic Rhinosinusitis With Nasal Polyps: A Case–Control Study

EPOS 2012 states that investigation is needed to study a possible role for food allergy in the initiation and perpetuation of chronic rhinosinusitis with nasal polyps (CRSwNP). Our main goal was to compare serum levels of food-specific immunoglobulin G (IgG) and IgE antibodies in patients with CRSwNP and controls. A prospective case–control study with 33 patients with CRSwNP and 31 controls without CRS was carried out. Clinical data were gathered through a systematic interview and blood sample was collected. Enzyme-linked immunosorbent assay tests using OmegaDiagnostics kit with 40 food allergens for detection of specific IgG antibodies were performed and food-specific IgE antibodies were determined by immunoassay using ImmunoCAP. Immunoglobulin classes and IgG subclasses levels were also evaluated. Statistical analysis was performed using SPSS v.23. The overall sum of food IgG antibodies was significantly lower in CRSwNP compared to control group, and this difference was also observed for different specific IgG antibodies (corn, soya, grain legumes, pear and apple, berries, citric fruit). In controls, a positive correlation between IgG1 and the sum of food IgG antibodies was seen, but in CRSwNP group a negative correlation was found. In addition, a significant higher level of IgG1 and lower IgG2 and IgG3 was found among patients with CRSwNP. Levels of serum-specific IgE antibodies against multiallergen food mix (fx5) and against shrimp, strawberry, orange, rye, or egg yolk, as well as the sum of food IgE antibodies, did not differ significantly between the groups. These findings suggest that food allergy does not have an important role in CRSwNP etiopathogenesis, whether it is IgG or IgE mediated. Moreover, the observed suppression of specific IgG antibodies against food allergens, its negative correlation with IgG1 and the IgG1 switching in CRSwNP, can be related to deviated IgG responses against other targets (eg, airborne particles) and warrants future investigation.

Food allergy

Food allergy is an immune response to food that can be classified as immunoglobulin (Ig)-E and non-IgE mediated. Milk, egg, peanut, tree nuts, and fish are among the most prevalent causes of food allergy. Mild reactions can include itchy rash, watering eyes, and nasal congestion while a severe reaction results in anaphylaxis. A detailed clinical history is essential when making a diagnosis, and skin prick testing and quantitative measurement of food-specific IgE antibodies can be helpful. Cow milk protein allergy causes a plethora of symptoms and frequently resolves spontaneously over the first 2 years of life; diagnosis is based mainly on clinical history. Food challenges have a pivotal role in the diagnosis of food allergy. Introduction of ‘allergic’ foods at 3–6 months alongside continuing breastfeeding may prevent allergy.