Immunoglobulin E-Binding Pattern of Canadian Peanut Allergic Children and Cross-Reactivity with Almond, Hazelnut and Pistachio.
Peanut allergic individuals can be both co-sensitized and co-allergic to peanut and tree nuts. At the moment, standard diagnostic approaches do not always allow differentiation between clinically relevant sensitization and nonsignificant cross-reactions, and the responsibility of each allergen remains unclear. The objective of this study was therefore to determine a peanut sensitization profile in a cohort of Canadian peanut allergic children and assess the immunoglobulin E (IgE) molecular cross-reactivity between peanut, almond, hazelnut and pistachio. The specific IgE (sIgE) levels of each patient serum were determined by ImmunoCAP, indirect ELISA and immunoblot to examine their sIgE-binding levels and profiles to peanut proteins. Reciprocal inhibition ELISA and immunoblotting were used to study sIgE cross-reactions between peanut and the selected tree nuts using an adjusted and representative serum pool of the nine allergic patients. The results showed that the prepared peanut and tree nut protein extracts allowed for the detection of the majority of peanut and selected tree nut known allergens. The reciprocal inhibition ELISA experiments showed limited sIgE cross-reactivities between peanut and the studied tree nuts, with peanut being most likely the sensitizing allergen and tree nuts the cross-reactive ones. In the case of hazelnut and pistachio, a coexisting primary sensitization to hazelnut and pistachio was also demonstrated in the serum pool. Reciprocal inhibition immunoblotting further revealed that storage proteins (2S albumin, 7S vicilin and 11S legumin) could possibly account for the observed IgE-cross-reactions between peanut and the studied tree nuts in this cohort of allergic individuals. It also demonstrated the importance of conformational epitopes in the exhibited cross-reactions.
Assessment of Pediatrician Awareness and Implementation of the Addendum Guidelines for the Prevention of Peanut Allergy in the United States.
Importance: The 2017 Addendum Guidelines for the Prevention of Peanut Allergy in the United States recommend that pediatricians assess infant peanut allergy risk and introduce peanut in the diet at age 4 to 6 months. Early introduction has the potential to prevent peanut allergy development. Objectives: To measure the rates of guideline awareness and implementation and to identify barriers to and factors associated with implementation among US pediatricians. Design, setting, and participants: This population-based study survey used a 29-item electronic survey instrument that was administered to pediatricians practicing across the United States from June 1, 2018, to December 1, 2018. Invitations to complete a survey were emailed to all pediatricians in the American Academy of Pediatrics vendor database. Eligible participants were nonretired US-based pediatricians providing general care to infants aged 12 months or younger. Main outcomes and measures: The primary outcome was the prevalence of guideline implementation, which was measured by 1 survey item about awareness followed by a second item about implementation. Secondary outcomes included identification of guidelines-focused services provided by pediatricians, knowledge of the guidelines (measured with 3 clinical scenarios), barriers to guideline implementation, need for training, and facilitators of guideline implementation. Results: A total of 1781 pediatricians were eligible to participate and completed the entire survey. Most respondents self-identified as white (1287 [72.5%]) and female (1210 [67.4%]) individuals. Overall, 1725 (93.4%; 95% CI, 92.2%-94.5%) pediatricians reported being aware of the guidelines. Of those pediatricians who had knowledge of the guidelines, 497 (28.9%; 95% CI, 26.8%-31.1%) reported full implementation and 1105 (64.3%; 95% CI, 62.0%-66.6%) reported partial implementation. Common barriers to implementation included parental concerns about allergic reactions (reported by 575 respondents [36.6%; 95% CI, 34.3%-39.1%]), uncertainty in understanding and correctly applying the guidelines (reported by 521 respondents [33.2%; 95% CI, 30.9%-35.6%]), and conducting in-office supervised feedings (reported by 509 respondents [32.4%; 95% CI, 30.1%-34.8%]). Many pediatricians (1175 [68.4%; 95% CI, 66.1%-70.5%]) reported a need for further training on the guidelines. Conclusions and relevance: This survey found that most pediatrician respondents appeared to know of the 2017 guidelines, but less than one-third of respondents reported full implementation. Results of this study may inform future efforts to eliminate barriers to guideline implementation and adherence, thereby reducing the incidence of peanut allergy in infants.
Interaction of Monocyte-Derived Dendritic Cells with Ara h 2 from Raw and Roasted Peanuts.
Ara h 2 is a relevant peanut allergen linked to severe allergic reactions. The interaction of Ara h 2 with components of the sensitization phase of food allergy (e.g., dendritic cells) has not been investigated, and could be key to understanding the allergenic potential of this allergen. In this study, we aimed to analyze such interactions and the possible mechanism involved. Ara h 2 was purified from two forms of peanut, raw and roasted, and labeled with a fluorescent dye. Human monocyte-derived dendritic cells (MDDCs) were obtained, and experiments of Ara h 2 internalization by MDDCs were carried out. The role of the mannose receptor in the internalization of Ara h 2 from raw and roasted peanuts was also investigated. Results showed that Ara h 2 internalization by MDDCs was both time and dose dependent. Mannose receptors in MDDCs had a greater implication in the internalization of Ara h 2 from roasted peanuts. However, this receptor was also important in the internalization of Ara h 2 from raw peanuts, as opposed to other allergens such as raw Ara h 3.
Oral immunotherapy for treatment of peanut allergy.
The US Food and Drug Administration's approval of a peanut oral immunotherapy product in January 2020 is a landmark development in the field of food allergy therapy. While food allergy prevalence has been increasing, this product is the first approved therapy for food allergy. Oral immunotherapy has many similarities to subcutaneous immunotherapy and drug desensitization protocols, but does not lead to sustained unresponsiveness. The studies leading to approval of the Palforzia product demonstrated increase in the amount of peanut protein able to be consumed, with 67% of subjects randomized to the treatment arm able to consume 600 mg of peanut protein in double-blind placebo-controlled food challenge at study exit. However, side effects are an important consideration, and dropout rates in studies of Palforzia ranged from 11% to 21%. Postmarketing surveillance of this product will be critical in assessing its long-term risks and benefits.
Comparative study of concatemer efficiency as an isotope-labelled internal standard for allergen quantification.
Mass spectrometry-based methods coupled with stable isotope dilution have become effective and widely used methods for the detection and quantification of food allergens. Current methods target signature peptides resulting from proteolytic digestion of proteins of the allergenic ingredient. The choice of appropriate stable isotope-labelled internal standard is crucial, given the diversity of encountered food matrices which can affect sample preparation and analysis. We propose the use of concatemer, an artificial and stable isotope-labelled protein composed of several concatenated signature peptides as internal standard. With a comparative analysis of three matrices contaminated with four allergens (egg, milk, peanut, and hazelnut), the concatemer approach was found to offer advantages associated with the use of labelled proteins, ideal but unaffordable, and circumvent certain limitations of traditionally used synthetic peptides as internal standards. Although used in the proteomic field for more than a decade, concatemer strategy has not yet been applied for food analysis.
Food allergens in skincare products marketed for children.
Background: The application of preparations containing food allergens can cause percutaneous sensitisation and provocation. The prevalence of food allergens in children's cosmetics is unknown. Objectives: To analyse the prevalence of food allergens in skincare products marketed for children and its association with marketing claims and product price. Methods: We reviewed 276 skincare product ingredient labels for the presence of milk, eggs, wheat, soy, oats, tree nuts, peanuts and sesame. Results: More than one third (108; 39.1%) of the products listed at least one allergen. A total of 156 allergens were recorded, of which 65 (41.7%) were almonds, 35 (22.4%) wheat, 24 (15.4%) soy, 16 (10.3%) oats, 13 (8.3%) sesame, 2 (1.3%) milk and 1 (0.6%) peanuts. Products that claimed to be natural or ecological were more likely to contain food allergens than those not labelled so (P < .001). The prices were higher for products containing food allergens compared to allergen-free products (P = .028). Conclusions: Food allergens are prevalent in children's cosmetics, especially those that claim to be natural or ecological. The most incorporated food allergens are almonds, wheat and soy. Products containing food allergens cost more than allergen-free ones.
Oxidative Stability of Protease Treated Peanut with Reduced Allergenicity.
Oxidative stability and allergenicity are two major concerns of peanuts. This study evaluated the impact of protease treatment of peanuts on its oxidative stability during storage. The raw and dry-roasted peanut kernels were hydrolyzed with Alcalase solution at pH 7.5 for 3 h. The contents of Ara h 1, Ara h 2, and Ara h 6 in peanuts were determined before and after enzyme treatment by a sandwich ELISA. After drying, the samples were packed in eight amber glass jars and stored at 37 °C for 1-8 weeks. Controls are untreated raw and dry-roasted peanuts packed and stored in the same way as their treated counterparts. Samples were taken biweekly to determine peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) as indicators of oxidation (n = 3), and to determine antioxidant activity. Alcalase treatment reduced intact major allergens Ara h 1, Ara h 2, and Ara h 6 by 100%, 99.8%, and 85%, respectively. The PVs of Alcalase-treated raw and roasted peanuts was lower than those of untreated (p < 0.05) over the 8-week storage. The TBARS of Alcalase-treated raw peanuts were slightly higher than that of untreated (p < 0.05), but the TBARS of Alcalase-treated dry-roasted peanuts were slightly but significantly lower than that of untreated (p < 0.05). The protease treatment increased the antioxidant activities including reducing power, DPPH free radical scavenging capacity, and metal chelating capacity of peanuts.
Food allergen sensitization patterns in a large allergic population in Mexico.
Introduction and objectives: Although food allergy is recognized as a growing worldwide public health problem, there continues to be limited data on prevalence rates in developing and emerging countries. Most prevalence estimates are based on self-reports, with only few studies using objective assessments. The aim was to analyze the frequency of sensitization to food allergens by serum specific IgE in a large group of unselected allergic patients in Mexico. Materials and methods: We analyzed data registries from patients of all ages with suspected food allergy referred to a specialized laboratory in Mexico City from January 2016 to April 2018. A descriptive analysis, and an age/food-group comparison were made. Results: A total of 2633 subjects tested for food allergy were identified during the study period; 1795 subjects fulfilled the inclusion criteria. The overall positivity (sIgE≥0.35kUA/L) to at least one food was 24%. The most frequently positive foods were hazelnut, apple, shrimp, peanut, egg white, egg yolk, peach, almond, tomato, bean, milk, strawberry, kiwi, maize and wheat. Positivity for some foods was more frequent across different age groups, in young children (≤5 years) milk; in older children (6-17 years): peanut, almond, wheat, soy and maize; in adults: apple. We also found other foods with high positivity but less than 50 samples: rye 60%, mango 42.9%, carrot 37.5%, cashew 27.3%, banana 21.1% and oat 20.6%. Conclusion: Our study reported the presence of a differential regional IgE sensitization pattern as compared with the internationally reported one, highlighting the importance of local staple foods.
The influence of cultural attitudes to nut exposure on reported nut allergy: A pilot cross sectional study.
Food allergies in children have become a common management and diagnostic concern and have a significant influence on general health-related quality of life. We investigated the prevalence of reported nut allergy between populations with different cultural attitudes to nuts during pregnancy and infancy. We conducted a survey to investigate the relationship between cultural differences in the consumption of nuts during pregnancy, breastfeeding and exposure to nuts in early childhood against the reported prevalence of nut allergy between three populations: Libyan, UK Libyan and a general UK population. The survey was administered to a representative sample of UK and Libyan parents with children aged between 3 and 16 years who were asked to report prevalence of nut allergy and to describe the factors that might affect this such as cultural behaviours and diet. A total of 1,123 parents responded. Nut allergy was defined as an allergic reaction that required medical treatment. The reported rates of nut allergy showed a significant difference in nut allergy between the Libyan populations and the general UK population with an increased odds ratio of nut allergy of ~10 when comparing the Native Libyan population to the UK population. The UK Libyan population reported the same low rate of allergic reactions as the Libyan population which were both significantly lower than the UK population (p < .0001). The Libyan populations showed significant differences from the UK population in exposure to nuts during pregnancy, breastfeeding and early infancy. The development of peanut and almond allergy through tolerance induction could be prevented by frequent and early ingestion of a moderate quantity of nuts during infancy and by maternal ingestion during pregnancy or lactation.
Prevalence of IgE‐mediated sensitization in patients with suspected food allergic reactions in Jordan.
Background: Despite the recognition of food allergies as a significant cause of morbidity and a growing public health burden worldwide, there are no epidemiological studies addressing food sensitization and allergy in Jordan. Objective: To conduct an epidemiological study that retrospectively analyzes sensitization data from 3463 patients with suspected immunoglobulin E (IgE)-mediated food allergic reactions who performed specific IgE tests in our laboratories in Jordan. Methods: Specific IgE (s-IgE) tests were analyzed for patients who performed enzyme allegro-sorbent testing based on either self-reported food allergy or upon physician's request. Results: 2.3% of the analyzed samples were cross-reactive to carbohydrate determinants. A quarter of the patients were sensitized to one or more food allergens, with males having higher odds of being s-IgE positive. Furthermore, a higher prevalence of sensitization was seen in infants and children compared with adults. s-IgE was most frequently found against cow milk (11.2%), pistachio (4.9%), soybean (4.6%), cherry (4.4%), and orange (4.4%). Interestingly, the s-IgE class distribution profile of pistachio differed from the rest of the top hits being skewed away from the weak class 1 leaning more towards higher IgE classes. Food allergen sensitization was age group-dependent: milk, tree nuts, and eggs were the main food groups causing sensitization in infants, while it was fruits followed by milk in children and adults. Conclusions: Our work represents the first epidemiological study addressing food sensitization in Jordan. This study lays a solid foundation for future studies that can help better guide food allergy diagnosis, patient dietary modifications, and food elimination plans, as well as assist decision-makers in the region to develop national strategies for an efficient and sustainable healthcare system.