Combining allergen components improves the accuracy of peanut allergy diagnosis.
Background: IgE to peanut often occurs in the absence of peanut allergy. Detection of allergen component sIgE has improved diagnosis and birthed molecular allergen component arrays, in which sensitisation to multiple allergen components can be measured simultaneously. Objective: To improve the diagnostic utility of serology for peanut allergy, by mapping interactions of sIgE to multiple components and IgE functional characteristics. Methods: A cohort of 100 children was studied, with a 60-children cohort employed for external validation. Levels of total IgE, sIgE to peanut and peanut components were measured using singleplex ImmunoCAP and multiplex ISAC. Peanut IgE specific activity, avidity and diversity were determined. Diagnostic modelling was performed using a Bayesian hierarchical model. Results: Sensitization to the 112 allergens on ISAC (model 1) demonstrated the highest accuracy to diagnose peanut allergy (AUC=0.92). Sensitization to peanut components on ISAC (model 2) reported an AUC of 0.86 and on singleplex (model 3) an AUC of 0.92, which was greater than that of Ara h 2-sIgE alone (AUC= 0.90). Functional characteristics of peanut-sIgE (model 4) reported an AUC of 0.89, which was in turn greater than that of peanut-sIgE (AUC=0.75). Model 3 offered the highest predictive value and the second highest overall diagnostic accuracy. Conclusions: SIgE to a combination of allergen components (Ara h 1, 2, 3 and 6) is highly predictive of peanut allergy and superior to individual markers. Combining the functional characteristics of IgE was superior to peanut-sIgE levels alone. These models can be applied in real-time during clinical consultations using online calculators. https://doi.org/10.1016/j.jaip.2021.08.029
Irradiation technology: An Effective and Promising Strategy for Eliminating Food Allergens.
Food allergies are one of the major health concerns worldwide and have been increasing at an alarming rate in recent times. The elimination of food allergenicity has been an important issue in current research on food. Irradiation is a typical nonthermal treatment technology that can effectively reduce the allergenicity of food, showing great application prospects in improving the quality and safety of foods. In this review, the mechanism and remarkable features of irradiation in the elimination of food allergens are mainly introduced, and the research progress on reducing the allergenicity of animal foods (milk, egg, fish and shrimp) and plant foods (soybean, peanut, wheat and nuts) using irradiation is summarized. Furthermore, the influencing factors for irradiation in the elimination of food allergens are analyzed and further research directions of irradiation desensitization technology are also discussed. This article aims to provide a reference for promoting the application of irradiation technology in improving the safety of foods. https://doi.org/10.1016/j.foodres.2021.110578
Identification of vicilin, legumin and antimicrobial peptide 2a as macadamia nut allergens.
Macadamia nut is an increasingly popular food item of a healthy diet. However, macadamia nut is also a potent allergenic food. To date, there is little information about the allergenic proteins involved. In this study, using sera from macadamia nut allergic individuals, four IgE-binding proteins were detected. Their identities were determined by tandem mass spectrometry with de novo sequencing. Three IgE-reactive proteins, the vicilin Mac i 1, the legumin Mac i 2 and the antimicrobial peptide 2a/Mac i 1 (28-76) were purified from the nut while the non-specific lipid transfer protein was produced as a recombinant in Pichia pastoris. IgE-binding assays using sera from well-characterized groups of tree nut and/or peanut allergic patients revealed that the allergens were mainly recognized by sera from macadamia nut allergic individuals. Hence, these newly discovered allergens will enable molecular diagnostics to identify patients at high risk of macadamia nut allergy. https://doi.org/10.1016/j.foodchem.2021.131028
Epigenetic programming underpins B‐cell dysfunction in peanut and multi‐food allergy.
Objective: Rates of IgE-mediated food allergy (FA) have increased over the last few decades, and mounting evidence implicates disruption of epigenetic profiles in various immune cell types in FA development. Recent data implicate B-cell dysfunction in FA; however, few studies have examined epigenetic changes within these cells. Methods: We assessed epigenetic and transcriptomic profiles in purified B cells from adolescents with FA, comparing single-food-allergic (peanut only), multi-food-allergic (peanut and ≥1 other food) and non-allergic (control) individuals. Adolescents represent a phenotype of persistent and severe FA indicative of a common immune deviation. Results: We identified 144 differentially methylated probes (DMPs) and 116 differentially expressed genes (DEGs) that distinguish B cells of individuals with FA from controls, including differential methylation of the PM20D1 promoter previously associated with allergic disorders. Subgroup comparisons found 729 DMPs specific to either single-food- or multi-food-allergic individuals, suggesting epigenetic distinctions between allergy groups. This included two regions with increased methylation near three S100 genes in multi-food-allergic individuals. Ontology results of DEGs specific to multi-food-allergic individuals revealed enrichment of terms associated with myeloid cell activation. Motif enrichment analysis of promoters associated with DMPs and DEGs showed differential enrichment for motifs recognised by transcription factors regulating B- and T-cell development, B-cell lineage determination and TGF-β signalling pathway between the multi-food-allergic and single-food-allergic groups. Conclusion: Our data highlight epigenetic changes in B cells associated with peanut allergy, distinguishing features of the epigenome between single-food- and multi-food-allergic individuals and revealing differential developmental pathways potentially underpinning these distinct phenotypes. https://doi.org/10.1002/cti2.1324
Preparation and in vitro bioactive evaluation of cashew-nut proteins hydrolysate as a potential source of anti-allergy peptides.
This work proposes a novel potential source of antiallergens based on bioactive peptides. Cashew-nut protein hydrolysate with antiallergic activity was prepared from cashew nuts through protease treatment. The change in the antiallergic activity of cashew-nut protein hydrolysate during in vitro simulated digestion was investigated. Cashew-nut protein hydrolysates were prepared through treatment using five different enzymes, namely, Alcalase, Protamex, Neutrase, papain, and bromelin. According to the results of molecular weight distribution, more small molecular weight peptides could be obtained by selecting Alcalase protease than other proteases, and the degree of hydrolysis, trichloroacetic acid-soluble peptide yield and hyaluronidase inhibitory rate of the hydrolysate were 17.0 ± 61.52%, 26.28 ± 0.13% and 62.06% ± 5.07%, which were significantly higher than those of other proteases. Therefore, Alcalase is the most suitable protease for the preparation of cashew-nut hydrolysates. Cashew-nut protein hydrolysates prepared with Alcalase under optimum conditions were fractionated through ultrafiltration. Fractions with low molecular weight exhibited the highest hyaluronidase inhibitory rate (90.57%) among all fractions. The inhibition of hyaluronidase activity during digestion showed that cashew-nut protein hydrolysate III (CPH III) has persistent antiallergic activity. Therefore, CPH III could serve as a potential source of functional peptides with health-promoting effects. https://doi.org/10.1007/s13197-020-04838-z
Food irradiation: a promising technology to produce hypoallergenic food with high quality.
The increasing incidence of food allergy cases is a public health problem of global concern. Producing hypoallergenic foods with high quality, low cost, and eco-friendly is a new trend for the food industry in the coming decades. Food irradiation, a non-thermal food processing technology, is a powerful tool to reduce the allergenicity with the above advantages. This review presents a summary of recent studies about food irradiation to reduce the allergenicity of food, including shellfish, soy, peanut, milk, tree nut, egg, wheat and fish. Principles of food irradiation, including mechanisms of allergenicity-reduction, irradiation types and characteristics, are discussed. Specific effects of food irradiation are also evaluated, involving microbial decontamination, improvement or preservation of nutritional value, harmful substances reduction of food products. Furthermore, the advantages, disadvantages and limitations of food irradiation are analyzed. It is concluded that food irradiation is a safety tool to reduce the allergenicity of food effectively, with high nutritional value and long shelf-life, making it a competitive alternative technology to traditional techniques such as heating treatments. Of note, a combination of irradiation with additional processing may be a trend for food irradiation.
Prevalence and early‐life risk factors for tree nut sensitization and allergy in young adults.
Background: Tree nut allergy may cause anaphylaxis. There are limited population-based studies on prevalence and early-life risk factors. Methods: We evaluated the prevalence of reported symptoms and allergic sensitization to tree nuts at age 24 years in the BAMSE population-based cohort study and assessed early-life factors associated with the development of tree nut allergy. We estimated tree nut allergy prevalence, by analysing questionnaire data on tree nut ingestion and symptoms at age 12, 16 and 24 years, and IgE sensitization at age 24 years to hazelnut, walnut, pecan, cashew, pistachio, Brazil nut, almond extracts and allergen molecules Cor a 1, 9, 14 (hazelnut), Jug r 1 (walnut) and Ana o 3 (cashew). We evaluated eczema, asthma, food allergies, inherited risk of allergy and gender as potential early-life risk factors. Results: Data were available for 2215/4089 (54%) BAMSE study participants, for estimation of the prevalence of tree nut sensitization (21.2%), tree nut allergy symptoms (9.8%) and combined sensitization and symptoms (7.9%, 2.1% for storage protein sensitization and symptoms, 4.3% for any sensitization and non-mild symptoms). Sixty-three per cent of sensitized individuals (295/470) were asymptomatic, but only 76/470 (16%) storage protein sensitized individuals. Egg allergy (ORadj 8.50 95% CI 2.15-33.6), eczema (ORadj 2.53 95% CI 1.21-5.32) and asthma (ORadj 5.59 95% CI 2.35-13.3)) at pre-school age were associated with future development of tree nut symptoms and storage protein sensitization. At age 24 years, tree nut allergy was associated with current eczema and with markers of current asthma severity. Sensitization to storage proteins was more strongly associated with symptoms than sensitization to whole extract for all tree nuts evaluated. Conclusions: In this Swedish cohort, we found tree nut whole extract sensitization is common but usually asymptomatic. Storage protein sensitization is a more reliable indicator of tree nut symptoms. Tree nut allergy is associated with early onset, persistent and severe atopic disease. https://doi.org/10.1111/cea.13994
IgE mediated food allergy in Turkey: different spectrum, similar outcome.
Background: Food allergies (FAs) potentially differ across cultures. Methods: All medical records of 534 children and adolescents with IgE-mediated FA over a 5-year period were reviewed to document the regional characteristics with regard to spectrum and outcome. Results: According to their last visit, the most common FAs were tree nuts (TNs) (52.4%), cow`s milk (27.3%), seeds (24.7%), egg white (23.2%) and peanuts (14.9%). Hazelnut and Anacardia nuts were the most common etiologies for TN allergies, whereas lentils and chickpeas for legumes and sesame and pumpkin seed for seeds were most common, respectively. TN allergy was in first place in school-age children (55.3%) and adolescents (57.1%) while in the second place in preschoolers (57.7%) after egg white (60%). Of these 534 children, 59.2% had at least one resolved FA (mainly egg white, cow`s milk) and 21% had no residual FA during the study period. Emerging FAs (fish, shellfish, fruit, TN and seed) after the age of 3 years was reported in 94 children. The prevalence of current asthma (22.3%, 38.2%, 40%) and allergic rhinitis (11.6%, 45.2%, 60%) increased, while current atopic dermatitis (17.5%, 8.6%, 8,6%) decreased in preschoolers, school age children and adolescents, respectively. Conclusions: The FA spectrum of Turkish children and adolescents differs from many regions of the world with high rates of TN (hazelnut, Anacardia nuts), seed (sesame, pumpkin seed) and lentils, and low rates of soy, peanut and seafood allergies. However, resolution, emergence and persistence of allergies and comorbidities are similar, which points to the limited role of the environment in the outcome. 10.24953/turkjped.2021.04.002
Diagnostic accuracy of Ara h 2 for detecting peanut allergy in children.
Background: Specific IgE to Ara h 2 is a diagnostic test for peanut allergy which may reduce the need for double-blind placebo-controlled food challenges (DBPCFC), however guidance for using Ara h 2 in place of DBPCFCs has not been validated. Objective: To prospectively evaluate 1) diagnostic accuracy of previously published Ara h 2 cutoff levels to diagnose peanut allergy in children and 2) costs. Methods: A consecutive series of 150 children age 3.5 to 18 years was evaluated in secondary and tertiary settings in the Netherlands. sIgE to Ara h 2 was the index test and oral peanut ingestion was the reference test. Oral peanut ingestion was home or supervised introduction for Ara h 2 ≤0.1, DBPCFC for 0.1-5.0 and open food challenge for ≥5.0 Costs were calculated using financial healthcare data. Results: A conclusive reference test was performed in 113 children (75%). Sixty-four children (57%) had peanut allergy, as confirmed by a DBPCFC (27/47) or an open challenge (37/50). Forty-nine children (43%) were considered peanut tolerant after peanut introduction (19/19), a DBPCFC (20/47) or an open challenge (10/50). Area under the curve for Ara h 2 was 0.94 (95% CI 0.90-0.98). The diagnostic flowchart correctly classified 26/26 (100%; 84-100) of children with Ara h 2 ≤0.1 as peanut-tolerant and 34/35 (97%; 83-100) of children with Ara h 2 ≥5.0 as peanut-allergic. At a cutoff of ≤ 0.1 and ≥5.0 a sensitivity of respectively 100% (93-100) and 53% (38-67) was observed and a specificity of 53% (38-67) and 98% (87-100). Mean annual costs of the flowchart were estimated as €320-€636 per patient lower than following national allergy guidelines. Conclusions: In this diagnostic accuracy study, which did not take into account pretest probability, we have validated previously published Ara h 2 cutoff levels which are associated with peanut tolerance and allergy. https://doi.org/10.1111/cea.13987
A remarkable food allergy in children: cashew nut allergy.
Objective: The prevalence of cashew nut allergy is increasing. Clinical reaction to cashew nuts may be severe, including anaphylaxis. In this study, we aimed to evaluate the frequency of cashew nut sensitivity in a group of children with food allergy and the clinical features and course of cashew nut allergy. Material and methods: A retrospective chart review was performed on 516 children who presented with food allergy at a pediatric allergy department. Individuals sensitized to cashew nuts were examined. Results: Cashew nut sensitization was detected in 17 (64.7% male; mean age of symptom onset, 14 months) of 516 patients with food allergy. Skin symptoms were the most frequent clinical presentation, followed by gastrointestinal symptoms. Overall, 29.4% of the patients presented with anaphylaxis. All anaphylactic reactions were developed after the first consumption of cashew nuts. Of the cashew nut-sensitized patients, 82.3% were diagnosed with moderate-to-severe atopic dermatitis, and all of them had multiple food allergies. During the follow-up, 90% of the patients who had cashew nut sensitization and co-existing food allergies to cow's milk and/or hen's egg developed tolerance to cow's milk and/or hen's egg, but none of the patients could tolerate cashew nut ingestion. Conclusion: Cashew nut is a potent allergen, causing severe allergic reactions that persist long term compared with other food allergies. Early onset of moderate-to-severe atopic dermatitis and multiple food allergies are remarkable co-existing conditions in children who have been diagnosed with cashew nut allergy. Pediatricians should be aware of this emerging food allergy.