Late introduction of solids into infants’ diets may increase the risk of food allergy development.
Background: This study investigated risk factors associated with food allergy or food intolerance among school children in two Swedish towns. Methods: Questionnaires were used to collect data on self-reported food allergy or intolerance (SRFA) in children aged 7-8 years from Mölndal in southwestern Sweden and Kiruna in northern Sweden. It included questions about specific food allergy or intolerance to cows' milk, hens' eggs, fish, peanuts, tree nuts, and cereals and also age of onset, type of symptoms and age of cessation. Information was also gathered on family allergy history, dietary habits, and certain lifestyle aspects. Results: Of 1838 questionnaires distributed, 1029 were returned: 717/1354 (53%) from Mölndal and 312/484 (64%) from Kiruna. The cumulative incidence of SRFA was 19.6% with a significantly higher cumulative incidence in Kiruna (28.5%) than in Mölndal (15.7%), P < .001. Solids were introduced at a later age in Kiruna. Introduction of solids into a child's diet from the age of 7 months or later, and maternal history of allergic disease, were both risk factors associated with a higher risk of food allergy or intolerance. Conclusion: Late introduction of solids into an infant's diet may be one risk factor for developing food allergy or intolerance. Later introduction of solids in Kiruna may be one explanation for the higher cumulative incidence of SRFA in that region.
The Utility of Genomic and Transcriptomic Data in the Construction of Proxy Protein Sequence Databases for Unsequenced Tree Nuts.
As the apparent incidence of tree nut allergies rises, the development of MS methods that accurately identify tree nuts in food is critical. However, analyses are limited by few available tree nut protein sequences. We assess the utility of translated genomic and transcriptomic data for library construction with Juglans regia, walnut, as a model. Extracted walnuts were subjected to nano-liquid chromatography-mass spectrometry (n-LC-MS/MS), and spectra were searched against databases made from a six-frame translation of the genome (6FT), a transcriptome, and three proteomes. Searches against proteomic databases yielded a variable number of peptides (1156-1275), and only ten additional unique peptides were identified in the 6FT database. Searches against a transcriptomic database yielded results similar to those of the National Center for Biotechnology Information (NCBI) proteome (1200 and 1275 peptides, respectively). Performance of the transcriptomic database was improved via the adjustment of RNA-Seq read processing methods, which increased the number of identified peptides which align to seed allergen proteins by ~20%. Together, these findings establish a path towards the construction of robust proxy protein databases for tree nut species and other non-model organisms.
HPLC-MS/MS Method for the Detection of Selected Toxic Metabolites Produced by Penicillium spp. in Nuts
Penicillium spp. are emerging as producers of mycotoxins and other toxic metabolites in nuts. A HPLC-MS/MS method was developed to detect 19 metabolites produced by Penicillium spp. on chestnuts, hazelnuts, walnuts and almonds. Two extraction methods were developed, one for chestnuts and one for the other three nuts. The recovery, LOD, LOQ and matrix effect were determined for each analyte and matrix. Correlation coefficients were always >99.99%. In walnuts, a strong signal suppression was observed for most analytes and patulin could not be detected. Six strains: Penicillium bialowiezense, P. brevicompactum, P. crustosum, P. expansum, P. glabrum and P. solitum, isolated from chestnuts, were inoculated on four nuts. Chestnuts favored the production of the largest number of Penicillium toxic metabolites. The method was used for the analysis of 41 commercial samples: 71% showed to be contaminated by Penicillium-toxins. Cyclopenin and cyclopenol were the most frequently detected metabolites, with an incidence of 32% and 68%, respectively. Due to the risk of contamination of nuts with Penicillium-toxins, future studies and legislation should consider a larger number of mycotoxins.
Diagnosis of Peanut Allergy Using Continuous Likelihood Ratios.
Background: Peanut allergy (PA) is associated with an economic and psychologic burden on patients and families. Its diagnosis includes tests for peanut specific IgE (sIgE), the values of which usually are categorized as positive or negative using a predefined cutoff (usually 0.35kU/L). With the use of Bayes theorem, this categorization can be replaced with a continuous interpretation if sIgE which accounts for the prevalence of PA and history of ingestion. Objective: We performed a pilot investigation with the results of oral food challenges (OFC) to evaluate a method for estimating the likelihood ratio (LR) for each value of sIgE. The LR could be used to estimate the probability of PA. Methods: OFC outcomes and serum IgE values from 117 children seen in an allergy clinic between January 2017 to November 2019 were obtained. Polynomial regression of the Receiver Operation Characteristics (ROC) curve was used to determine a LR for each value of sIgE. Linear regression was used to estimate a LR for each of value of sIgE. Results: sIgE ranged from <0.1kU/L to 35kU/L. Bayes' theorem and a ROC curve was used to estimate LRs for each value of peanut sIgE. The value of IgE associated with a LR of 1 was 0.22kU/L, which is comparable to other studies that used a value of 0.35kU/L to separate positive from negative results. Conclusion: When combined with estimates of pretest probability, this method should permit development of computerized decision-making algorithms to estimate the probability that a patient has peanut allergy.
Consensus Report from the Food Allergy Research and Education (FARE) 2019 Oral Immunotherapy for Food Allergy Summit.
Food allergy is a major health problem affecting 5 to 10% of the population in developed nations, including an estimated 32 million Americans. Despite the large number of patients suffering from food allergies, up until the end of January 2020, no treatment for food allergies had been approved by the U.S. Food and Drug Administration (FDA). The only options were avoidance of food allergen triggers and acute management of allergic reactions. A considerable body of data exists supporting oral immunotherapy (OIT) as a promising, novel treatment option, including that for the now FDA-approved peanut OIT product, Palforzia. However, data for long-term quality of life improvement with OIT varies, depending on the measures used for analysis. Like many therapies, OIT is not without potential harms, and burdens, and the evaluation of patient-specific risk-benefit ratio of food OIT produces challenges for clinicians and patients alike, with many unanswered questions. Food Allergy Research & Education (FARE) organized the Oral Immunotherapy for Food Allergy Summit on November 6, 2019 modeled after the PRACTALL sessions between the European Academy of Allergy and Clinical Immunology (EAACI) and the American Academy of Allergy, Asthma and Immunology (AAAAI) to address these critical issues. Health care providers, patient representatives, researchers, regulators and food allergy advocates came together to discuss OIT and identify areas of common ground as well as gaps in existing research and areas of uncertainty and disagreement. The purpose of this paper is to summarize that discussion and facilitate collaboration among clinicians and patients to help them make better-informed decisions about offering and accepting OIT, respectively, as a therapeutic option.
Expression and activation of the steroidogenic enzyme CYP11A1 is associated with IL-13 production in T cells from peanut allergic children.
Activation of the steroidogenic enzyme CYP11A1 was shown to be necessary for the development of peanut-induced intestinal anaphylaxis and IL-13 production in allergic mice. We determined if levels of CYP11A1 in peripheral blood T cells from peanut-allergic (PA) children compared to non-allergic controls were increased and if levels correlated to IL-13 production and oral challenge outcomes to peanut. CYP11A1 mRNA and protein levels were significantly increased in activated CD4+ T cells from PA patients. In parallel, IL-13 production was significantly increased; IFNγ levels were not different between groups. There were significant correlations between expression levels of CYP11A1 mRNA and levels of IL13 mRNA and protein, levels of serum IgE anti-Ara h 2 and to outcomes of peanut challenge. The importance of CYP11A1 on cytokine production was tested using a CYP11A1 CRISPR/Cas9 KO plasmid or an inhibitor of enzymatic CYP11A1 activity. Inhibition of CYP11A1 activation in patient cells treated with the inhibitor, aminoglutethimide, or CD4+ T cell line transfected with the CYP11A1 KO plasmid resulted in reduced IL-13 production. These data suggest that the CYP11A1-CD4+Tcell-IL-13 axis in activated CD4+ T cells from PA children is associated with development of PA reactions. CYP11A1 may represent a novel target for therapeutic intervention in PA children.
Epitopes with similar physicochemical properties contribute to cross reactivity between peanut and tree nuts.
Many individuals with peanut (PN) allergy have severe reactions to tree nuts (TN) such as walnuts or cashews. Although allergenic proteins in TN and PN have overall low identity, they share discrete sequences similar in physicochemical properties (PCP) to known IgE epitopes. Here, PCP-consensus peptides (cp, 13 aa and 31 aa) were identified from an alignment of epitope rich regions of walnut vicilin, Jug r 2, leader sequence (J2LS) and cross-reactive epitopes in the 2S albumins of peanut and synthesized. A peptide similarity search in the Structural Database of Allergenic Proteins (SDAP) revealed a network of peptides similar (low property distance, PD) to the 13 aa cp (13cp) in many different plant allergens. Peptides similar to the 13cp in PN and TN allergens bound IgE from sera of patients allergic to PN and TN in peptide microarray analysis. The 13cp was used to produce a rabbit consensus peptide antibody (cpAB) that detected proteins containing repeats similar to the 13cp in western blots of various nut extracts, in which reactive proteins were identified by mass spectrometry. The cpAB bound more specifically to allergens and nut extracts containing multiple repeats similar to the 13 cp, such as almond (Pru du 6), peanut (Ara h 2) and walnut (Jug r 2). IgE binding to various nut extracts is inhibited by recombinant J2LS sequence and synthetic 31cp. Thus, several repeated sequences similar to the 13cp are bound by IgE. Multiple similar repeats in several allergens could account for reaction severity and clinically relevant cross-reactivity to PN and TN. These findings may help improve detection, diagnostic, and therapeutic tools.
Effect of Instant Controlled Pressure Drop (DIC) treatment on the detection of nut allergens by Real Time PCR.
Tree nuts show nutritional properties and human health benefits. However, they contain allergenic proteins, which make them harmful to the sensitised population. The presence of tree nuts on food labelling is mandatory and, consequently, the development of suitable analytical methodologies to detect nuts in processed foods is advisable. Real-Time PCR allowed a specific and accurate amplification of allergen sequences. Some food processing methods could induce structural and/or conformational changes in proteins by altering their allergenic capacity, as well as produce the fragmentation and/or degradation of genomic DNA. In this work, we analysed by means of Real-Time PCR, the influence of pressure and thermal processing through Instant Controlled Pressure Drop (DIC) on the detectability of hazelnut, pistachio and cashew allergens. The detection of targets in hazelnut, pistachio and cashew (Cor a 9, Pis v 1 and Ana o 1, respectively) is affected by the treatment to different extents depending on the tree nut. Results are compared to those previously obtained by our group in the analysis of different treatments on the amplificability of the same targets. Reduction in amplificability is similar to that reported for some autoclave conditions. Our assays might allow for the detection of up to 1000 mg/kg of hazelnut, pistachio and cashew flours after being submitted to DIC treatment in food matrices.
Preventing food allergy in infancy and childhood: systematic review of randomised controlled trials.
Background: This systematic review of ways to prevent immediate-onset/IgE-mediated food allergy will inform guidelines by the European Academy of Allergy and Immunology (EAACI). Methods: The GRADE approach was used. Eleven databases were searched from 1946 to October 2019 for randomised controlled trials (and large prospective cohort studies in the case of breastfeeding). The studies included heterogeneous interventions, populations and outcomes so were summarised narratively. Results: Forty-six studies examined interventions to reduce the risk of food allergy in infancy (up to one year) or early childhood. The following interventions for pregnant or breastfeeding women and/or infants may have little to no effect on preventing food allergy but the evidence is very uncertain: dietary avoidance of food allergens, vitamin supplements, fish oil, probiotics, prebiotics, synbiotics and emollients. Breastfeeding, hydrolysed formulas and avoiding cow's milk formula may not reduce the risk of cow's milk protein allergy, however temporary supplementation with cow's milk formula in the first week of life may increase the risk of cow's milk allergy. Introducing well-cooked egg, but not pasteurised raw egg, from four to six months probably reduces the risk of hen's egg allergy. Introducing regular peanut consumption into the diet of an infant at increased risk beginning from four to 11 months probably results in a large reduction in peanut allergy in countries with a high prevalence. These conclusions are based on moderate certainty evidence, from single trials in high-income countries. Conclusions: Sixty percent of the included studies were published in the last ten years, but much still remains to be understood about preventing food allergy. In particular, there is a need to validate the potential benefits of early introduction of food allergens in a wider range of populations.
APPEAL‐1: A multiple country European survey assessing the psychosocial impact of peanut allergy.
Background: Peanut allergy (PA) is a common, potentially life-threatening, and typically lifelong condition with a significant burden of illness. However, information is lacking on how persons with PA (PwPA) and their caregivers perceive the psychosocial impact of living with PA. The Allergy to Peanuts imPacting Emotions And Life study 1 (APPEAL-1) survey, conducted across Europe, investigated the experience and impact of living with PA. Here, we report data evaluating the psychosocial impact of PA on PwPA and their caregivers. Methods: APPEAL-1 was an online survey conducted in 8 European countries. Representatives of 8 patient advocacy groups and 5 healthcare-research specialists developed the survey. Eligible respondent groups included: adults diagnosed with PA (self-report); parent/nonparent caregivers (proxy-report for a child with PA); and parent/nonparent caregivers (self-report of PA impact on themselves). Results: Of 1846 total study respondents, 419 were adults with PA (self-report); 546 were parents/ caregivers (proxy-report) ; 881 were parents/caregivers (self-report). Most respondents reported lifestyle restrictions regarding food (84-93%) and additional domains including parties and socializing, holiday activities and destinations, and taking public transport (53-89%). Approximately 40% rated themselves as "very" frustrated and "very" stressed. Two-thirds (65%) felt socially isolated; 43% were bullied. Less than half felt confident in knowing when to use an adrenaline autoinjector. Several intercountry differences were observed such as high levels of uncertainty and stress in respondents from Ireland, highest rates of anxiety in respondents from Germany, and social exclusion and isolation most common in respondents from France. Conclusions: PA imposes an adverse psychosocial impact on patients and caregivers, leading to frustration, stress, and isolation. Attention to the impact of PA is needed in research and clinical practice to improve PA healthcare and public education programs.