Identification of Almond ( Prunus dulcis) Vicilin As a Food Allergen.

Almond (Prunus dulcis) is not only widely used as a human food as a result of its flavor, nutrients, and health benefits, but it is also one of the most likely tree nuts to trigger allergies. Almond allergens, however, have not been studied as extensively as those of peanuts and other selected tree nuts. This review provides an update of the molecular properties of almond allergens to clarify some confusion about the identities of almond allergens and our perspective on characterizing putative almond allergens. At present, the following almond allergens have been designated by the World Health Organization/International Union of Immunological Societies Allergen Nomenclature Sub-Committee: Pru du 3 (a non-specific lipid transfer protein 1, nsLTP1), Pru du 4 (a profilin), Pru du 5 (60S acidic ribosomal protein 2), Pru du 6 (an 11S legumin known as prunin) and Pru du 8 (an antimicrobial protein with cC3C repeats). Besides, almond vicilin and almond γ-conglutin have been identified as food allergens, although further characterization of these allergens is still of interest. In addition, almond 2S albumin was reported as a food allergen as a result of the misidentification of Pru du 8. Two more almond proteins have been called allergens based on their sequence homology with known food allergens and their 'membership' in relevant protein families that contain allergens in many species. These include the pathogenesis related-10 protein (referred to as Pru du 1) and the thaumatin-like protein (referred to as Pru du 2). Almonds thus have five known food allergens and five more likely ones that need to be investigated further. Published 2020. This article is a U.S. Government work and is in the public domain in the USA.

Differences In Food Allergy Quality Of Life Between Caregivers In a Clinic-Based and a Caregiver-Reported Food Allergic Population

Possession of epinephrine auto-injectors by Canadians with food allergies

Background: Food allergies (FA) are an important public health concern that place a major burden on the lives of children and their families. The complex pathogenesis of FAs results in multisystemic and heterogenous clinical presentations. Objective: To evaluate, according to immune mechanisms, the characteristics and risk factors of childhood FA in Turkey. Methods: This descriptive multicenter study included 1248 children with FA, aged < 18 years,, who were evaluated by pediatric allergists in 26 different centers. Results: Immune mechanisms of FA were immunoglobulin E (IgE) mediated in 71.8%, non-IgE mediated in 15.5%, and mixed IgE/non-IgE mediated in 12.7% of the patients. An episode of anaphylaxis had occurred in 17.6% of IgE-mediated FA. The most common food allergens were classified into five categories (in order of decreasing frequency): cow's milk, egg, tree nuts and/or peanut, wheat, and seafood. Allergies to cow's milk and egg declined significantly with age, whereas tree nuts and/or peanut allergies increased with age. The 0-2 year age group accounted for 62.5% of the cases. The most frequent cause of FA and food anaphylaxis was cow's milk before age 13 years and tree nuts and/or peanut during adolescence (ages 13-18 years). Compared with other phenotypes, male sex (odds ratio [OR] 1.486; p = 0.032), sibling(s) (OR 1.581; p = 0.021), and maternal atopy (OR 1.531; p = 0.045) increased the likelihood of IgE-mediated FA, whereas high household income (OR 1.862; p = 0.026) increased the likelihood of non-IgE-mediated FA in multivariate regression analysis. Conclusion: This study showed that the clinical findings of FA were highly variable, depending on age and underlying immune mechanism. Knowing the population characteristics will enable better management of FA in children.

The 2021 AAAAI Foundation Faculty Development awardees

Self-reported allergic reactions to peanut and tree nuts occurring on commercial airlines

Adverse reactions to foods are a diverse group of clinical syndromes resulting from immunologic and non-immunologic responses to food ingestion. Symptoms can range from mild, self-limiting reactions to severe, life-threatening reactions depending on the mechanism. This review primarily focuses on the clinical manifestations of immunologically derived adverse food reactions or food allergies.The true prevalence of food allergy is unknown. Up to 25% of the general population believes that they may be allergic to some food; however, the actual prevalence of food allergy diagnosed by a provider appears to be 1.5% to 2% of the adult population and approximately 6% to 8% of children. This discrepancy makes it imperative that clinicians are aware of the different food allergy syndromes. With a clear understanding of the clinical manifestations of food allergies, an accurate diagnosis and treatment plan can be formulated. Failing to do so may result in unnecessary dietary restrictions that may adversely affect nutritional status, growth, and quality of life.Most food allergic reactions are secondary to a limited number of foods, and the most common foods causing allergic reactions in children include milk, egg, peanuts, tree nuts, and fish. In adolescents and adults, allergies to peanuts, tree nuts, fish, and shellfish are most prevalent. Food allergies can result from immunoglobulin E (IgE)-mediated, non-IGE-mediated, or mixed IgE/non-IgE mechanisms. The purpose of this review is to discuss the clinical manifestations of each of these types of food allergy.

Background: Incidents of severe and fatal anaphylaxis to accidentally ingested food allergens are increasing. Individuals are more likely to encounter difficulties when eating away from home. In restaurants, front-of-house and kitchen staff may be called upon to provide information about ingredients or ensure certain food allergens are excluded from dishes. Following a series of reactions related to the accidental ingestion of peanuts in curries we assessed food allergy awareness and allergen avoidance practices amongst the staff of Asian-Indian restaurants. Methods: A questionnaire survey was administered by telephone to one member of staff in each restaurant. Results: Fifty percent (40/80) of restaurants participated. Responders included managers, owners, waiters and chefs. Most (90%) had received food hygiene training, but only 15% food allergy training. 25% could name three common food allergens. 3 in 4 listed nuts, but less than 1in 5 mentioned peanuts. Common misunderstandings included 60% of staff believing an individual experiencing an allergic reaction should drink water to dilute the allergen. A less prevalent, but perhaps more concerning, was the misunderstanding that cooking food would prevent it causing an allergic reaction (25%). Despite poor knowledge, all respondents were comfortable and 65% were “very comfortable” with providing a “safe” meal for a customer with a food allergy. 60% expressed interest in future food allergy training. Conclusions: Despite high confidence in their own understanding of allergy, many staff lacked the knowledge to provide “safe” meals for food allergic customers. Traditionally tree nuts are a common ingredient in Asian-Indian dishes cuisine and there was widespread, but not universal, awareness of tree nuts as a common allergen. Peanuts were less commonly recognised as a common allergen, an observation of extreme concern as peanuts are being substituted for tree nuts as they are cheaper and avoid having to inflate meal prices. Our data highlights the need for greater training of restaurant staff. In parallel, food allergic customers need to exercise vigilance when making meal choices and develop skills to order a safe meal. The management of allergy is multifaceted, and this study indicates the importance of health professionals working beyond the clinical setting to collaborate with colleagues in the hospitality industry, public health and environmental health in coordinated endeavours to improve patient safety.

Background: Studies suggest an increase in food allergy prevalence over the last decade, but the contributing factors remain unknown. The aim of this study was to evaluate the association between the most common food allergies and atopic history, sociodemographic characteristics and lifestyle habits. Methods: We conducted a case-control study nested within the SPAACE study (Surveying Prevalence of Food Allergy in All Canadian Environments) - a cross-Canada, random telephone survey. Cases consisted of individuals with probable food allergy (self-report of convincing symptoms and/or physician diagnosis) to milk, egg, peanut, tree nut, shellfish, fish, wheat, soy, or sesame. Controls consisted of nonallergic individuals, matched for age. Cases and controls were queried on personal and family history of atopy, sociodemographic characteristics and lifestyle habits. Multivariate logistic regression was used to evaluate the association between atopy, sociodemographic characteristics and lifestyle habits with probable food allergy. Results: Between September 2010 and September 2011, 480 cases and 4,950 controls completed the questionnaire. For all 9 allergens, factors associated with a higher risk of probable allergy were as follows: (1) personal history of eczema (in the first 2 years of life), asthma or hay fever (odds ratio, OR 2.3, 95% CI 1.6-3.5; OR 2.8, 95% CI 2.2-3.6, and OR 2.3, 95% CI 1.8-3.0, respectively), (2) maternal, paternal or sibling's food allergy (OR 3.7, 95% CI 2.5-5.6; OR 3.0, 95% CI 1.8-5.1, and OR 3.1, 95% CI 2.2-4.2), (3) high household income (top 20%; OR 1.5, 95% CI 1.2-2.0). Males and older individuals were less likely to have food allergy (OR 0.7, 95% CI 0.6-0.9, and OR 0.99, 95% CI 0.99-1.00). Eczema in the first 2 years of life was the strongest risk factor for egg, peanut, tree nut and fish allergy. Conclusions: This is the largest population-based nested case-control study exploring factors associated with food allergies. Our results reveal that, in addition to previously reported factors, eczema in the first 2 years of life is consistently associated with food allergies.

Food allergy is a costly, potentially life-threatening condition. Although studies have examined the prevalence of childhood food allergy, little is known about prevalence, severity, or health care utilization related to food allergies among US adults. To provide nationally representative estimates of the distribution, severity, and factors associated with adult food allergies. In this cross-sectional survey study of US adults, surveys were administered via the internet and telephone from October 9, 2015, to September 18, 2016. Participants were first recruited from NORC at the University of Chicago's probability-based AmeriSpeak panel, and additional participants were recruited from the non-probability-based Survey Sampling International (SSI) panel. Demographic and allergic participant characteristics. Self-reported food allergies were the main outcome and were considered convincing if reported symptoms to specific allergens were consistent with IgE-mediated reactions. Diagnosis history to specific allergens and food allergy-related health care use were also primary outcomes. Estimates were based on this nationally representative sample using small-area estimation and iterative proportional fitting methods. To increase precision, AmeriSpeak data were augmented by calibration-weighted, non-probability-based responses from SSI. Surveys were completed by 40 443 adults (mean [SD] age, 46.6 [20.2] years), with a survey completion rate of 51.2% observed among AmeriSpeak panelists (n = 7210) and 5.5% among SSI panelists (n = 33 233). Estimated convincing food allergy prevalence among US adults was 10.8% (95% CI, 10.4%-11.1%), although 19.0% (95% CI, 18.5%-19.5%) of adults self-reported a food allergy. The most common allergies were shellfish (2.9%; 95% CI, 2.7%-3.1%), milk (1.9%; 95% CI, 1.8%-2.1%), peanut (1.8%; 95% CI, 1.7%-1.9%), tree nut (1.2%; 95% CI, 1.1%-1.3%), and fin fish (0.9%; 95% CI, 0.8%-1.0%). Among food-allergic adults, 51.1% (95% CI, 49.3%-52.9%) experienced a severe food allergy reaction, 45.3% (95% CI, 43.6%-47.1%) were allergic to multiple foods, and 48.0% (95% CI, 46.2%-49.7%) developed food allergies as an adult. Regarding health care utilization, 24.0% (95% CI, 22.6%-25.4%) reported a current epinephrine prescription, and 38.3% (95% CI, 36.7%-40.0%) reported at least 1 food allergy-related lifetime emergency department visit. These data suggest that at least 10.8% (>26 million) of US adults are food allergic, whereas nearly 19% of adults believe that they have a food allergy. Consequently, these findings suggest that it is crucial that adults with suspected food allergy receive appropriate confirmatory testing and counseling to ensure food is not unnecessarily avoided and quality of life is not unduly impaired.

Adverse Food Reactions—An Emerging Issue for Adults

Background Lipid transfer proteins (LTPs) are the most common cause of primary food allergy and food-induced anaphylaxis in Southern European countries (Mediterranean and Atlantic areas). They are widely distributed in the outer layer of plant-based foods as well as in the pollen of trees and herbaceous plants. Due to their biochemical and molecular characteristics, LTPs exhibit high resistance to enzymatic digestion, acidic pH, and heat, leading to immunological cross-reactivity with unrelated foods or pollens in patients sensitized to these proteins. LTPs are considered complete food allergens (Class I allergens) capable of sensitizing through the gastrointestinal tract, with peach LTP (Pru p 3) often acting as the primary sensitizer, subsequently directing the immune response towards recognizing other LTPs. The aim of this study was to determine the LTP sensitization profile and its association with food allergies in patients consulting the allergy department in our region. Methods Samples were collected from patients attending our allergy department with suspected LTP sensitization. Once sensitization was confirmed through a positive intradermal test for LTP, demographic data, clinical allergy history, and diagnostic test results were recorded. In vivo testing was conducted using intradermal skin tests, while in vitro testing involved specific IgE determination using LTP-RUO immunoblot assay strips from Euroimmun®, which include six recombinant allergens and four allergen mixtures. Results A total of 96 samples were collected, including 13 negative controls. The average patient age was 35 years, with a majority of female participants (55%). Among the specific IgE tests for LTP analyzed, 25 patients (30.1%) tested positive for all LTPs, 11 patients (13.3%) tested positive for between 1 and 5 of the studied LTPs, and 55 patients (66.3%) tested positive for more than 5. Seventeen participants (20.5%) tested negative for all LTPs but showed reactivity to aeroallergens (mainly pollen family) through intradermal skin testing. The Pru p 3 test (peach LTP), considered the primary sensitizer, was negative in 19 participants (22.9%), with no positive results for any of the other measured LTPs. We found two patients who tested negative for Pru p 3 but positive for other LTPs: one for X2 Pha v3 (green bean) and the other for both X4 Sola L (tomato) and X2 Pha v3 (green bean). Conclusion LTP sensitization in our geographic area is predominantly linked to Pru p 3 but it cannot be considered a prototypical marker of this syndrome. LTP allergy is very common in Mediterranean countries and can cause potentially life-threatening reactions. This highlights the need to understand the clinical and immunological characteristics that can help identify and prevent anaphylactic episodes in patients exposed to LTP-containing foods

There is considerable debate about the prevalence and relevance of food allergy (FA) in atopic dermatitis (AD). The aim of this study was to investigate the prevalence of and risk factors for FA in a cohort of children with AD attending a multidisciplinary paediatric allergy clinic. The analysis was performed on 386 children (50.8% boys, median age 4 years) consecutively evaluated for AD. A diagnosis of FA was established on positive skin tests and/or a specific IgE value or a positive oral food challenge. Point prevalence of FA was 17.8%. Egg, peanuts, milk, tree nut and mustard accounted for 93% of cases. 37.7% of children had ≥2 positive food reactions. Risk factors associated with FA were young age (OR=7.9 when ≤2 years compared with ≥5 years), moderate to severe AD (OR=7.8 for severe and 2.4 for moderate AD) and onset of AD before 3 months of age (OR=5.7). Point prevalence of FA in children with AD is lower than initially reported in patients recruited in a paediatric allergology setting. Children≤2 years of age with early-onset or severe AD are at higher risk of FA and may be candidates for FA evaluation.

2S albumins are relevant and often major allergens from several tree nuts and seeds, affecting mainly children and young people. The present study aims to assess how the structural features of 2S albumins could affect their immunogenic capacity, which is essential to comprehend the role of these proteins in food allergy. For this purpose, twelve 2S albumins were isolated from their respective extracts by chromatographic methods and identified by MALDI-TOF mass-spectrometry. Their molecular and structural characterization was conducted by electrophoretic, spectroscopic and in silico methods, showing that these are small proteins that comprise a wide range of isoelectric points, displaying a general high structure stability to thermal treatment. Despite low amino acid sequence identity, these proteins share structural features, pointing conformational epitopes to explain cross-reactivity between them. Immunoblotting with allergic patients’ sera revealed those possible correlations between evolutionarily distant 2S albumins from different sources. The availability of a well-characterized panel of 2S albumins from plant-derived sources allowed establishing correlations between their structural features and their allergenic potential, including their role in cross-reactivity processes.

Prevalence of Physician-Reported Food Allergy in Canadian Children