Oral food challenge to wheat: a near-fatal anaphylaxis and review of 93 food challenges in children

Is Wheat Glutenin Extract Intrinsically Allergenic? Evaluation Using a Novel Adjuvant-Free Mouse Model of Systemic Anaphylaxis

Wheat is a prominent allergenic food that can trigger life-threatening anaphylaxis. Presently, it remains unclear whether wheat glutenin (WG) extract possesses inherent sensitization potential independently, without the use of adjuvants, and whether it can sensitize mice to the extent of inducing life-threatening systemic anaphylaxis. In this study, we tested the hypothesis that repeated skin exposures to WG extract without adjuvant will sensitize mice with the resultant anaphylactic reaction upon systemic WG challenge. Balb/c mice were bred and maintained on a strict plant protein-free diet and were repeatedly exposed to a WG extract or vehicle once a week for 9 weeks. WG-specific (s)IgE and total (t)IgE levels were quantified. Mice were challenged with WG extract to induce anaphylactic reactions as measured by hypothermic shock response (HSR) and mucosal mast cell degranulation response (MMCR). We also conducted proteomic analysis of 120 spleen immune markers. These skin-sensitized mice exhibited exposure-dependent IgE responses and near-fatal anaphylaxis upon challenge. Proteomic analysis identified seven dramatically elevated immune biomarkers in anaphylactic mice. These data reveal that WG is intrinsically allergenic, and that chronic skin exposure to WG extract can prime the mice for potentially fatal anaphylaxis.

Clinical profiles of patients with wheat-induced anaphylaxis at various ages of onset

Background

Wheat-induced anaphylaxis (WIA) is a serious and potentially life-threatening wheat allergy, more common in adults than in children. Little is known about the differences in clinical profiles in WIA among patients of various ages in China.

Methods

We analyzed data retrospectively from an allergy department in a tertiary hospital that included 248 patients (208 adults and 40 children and adolescents) with a history of WIA.

Results

We found that alcohol was more frequent in patients aged ≥50 years [older adults] (19.0%, 4/21) than in those aged 12-17 years [adolescents] (0%, 0/33; p = 0.019). The frequency of NSAID use in older adults (42.9%, 9/21) was significantly higher than that in adolescents (0%, 0/33; p < 0.001), and patients aged 18-49 years [young adults] (2.8%, 5/178; p < 0.001). During WIA, cardiovascular symptoms in children were less frequent than those in other age groups (children, 28.6%; adolescents, 87.9%; young adults, 93.0%; older adults, 95.2%; p < 0.001). The consciousness loss rate in adults (both age groups; p < 0.001) and the hypotension rate in older adults (p = 0.006) were higher than those in other age groups. Compared with adults (young and older adults), children had a higher rate of allergic comorbidities (p = 0.004, 0.001, respectively) and a higher rate of other food allergies (p < 0.001, <0.001, respectively). Compared with the mild-to-moderate anaphylaxis group, the severe anaphylaxis group had a higher onset age (p = 0.001), higher cofactor prevalence (p = 0.004), lower allergic comorbidity rate (p = 0.014), and higher positive rate of specific IgE to omega-5 gliadin (ω-5 gliadin) (p = 0.023).

Conclusion

Clinical profiles of patients with WIA are different among various onset age/severity groups. An improved understanding of WIA symptoms in various age/severity groups could help accelerate diagnosis, suggest preventive measures, and contribute to improved patient care.

IgE Mediated Wheat Allergy Associated with Resistant and Severe Forms of Allergic Conjunctivitis

Objective:

This study aimed to determine the prevalence and criteria of wheat allergy (WA) among patients with resistant allergic conjunctivitis (AC).

Methods:

A prospective comparative study was conducted on 100 patients with resistant AC. Skin prick-tests (SPTs), total and sIgE against a panel of inhalant and food allergens were performed in all patients’ sera. They were divided into 2 groups according to skin prick test (SPT) and specific IgE (sIgE) level, namely the wheat sensitive group (WSG) and wheat tolerant group (WTG). Total ocular symptom scores (TOSS) and 4-point sign scales were correlated for both groups.

Results:

Ten patients out of 100 with IgE-mediated resistant AC were wheat sensitive, and the other 90 were wheat tolerant patients. WSG included patients of significantly younger age. Positive family history of atopy was proven in 100% of WSG vs. 67% of WTG. A significantly higher frequency of multiorgan allergy was detected in 100% of WSG vs. 20% in WTG (P = 0.0001). Thirty (30%) of WSG had associated allergic rhinitis (AR) and bronchial asthma (BA). Another 30% had an associated AR only, 10% had an associated BA only, and another 20% had an associated skin allergy. TOSS, 4- point sign scale, and total IgE level were significantly higher in WSG.

Conclusion:

This study provides novel evidence that wheat allergy is responsible for some severe forms of AC.

An Adjuvant-Free Mouse Model Using Skin Sensitization Without Tape-Stripping Followed by Oral Elicitation of Anaphylaxis: A Novel Pre-Clinical Tool for Testing Intrinsic Wheat Allergenicity

Wheat is a major food allergen per the regulatory bodies of various nations. Hypersensitivity reactions to wheat have been steadily increasing for reasons that are not completely understood. Wheat-allergy models typically use adjuvants to induce sensitization to wheat proteins followed by an intraperitoneal challenge to elicit anaphylaxis. Although these models are very useful, they lack the ability to reveal the intrinsic allergenicity potential of wheat. To improve the mouse model of wheat allergy, we tested the hypothesis that repeated skin application of salt-soluble protein extract (SSPE) from durum wheat will clinically sensitize the mice to oral anaphylaxis to SSPE. Balb/c mice were bred and maintained on a plant-protein-free diet and used in the experiments. Adult female mice were exposed to SSPE once a week for 9 weeks via a solution on intact skin. Sensitization was measured by SSPE-specific IgE (sIgE) antibody and total IgE (tIgE) levels. Oral anaphylaxis was quantified by hypothermic shock response (HSR), and mucosal mast cell response (MMCR) was quantified by measuring MMCP-1 after oral challenge. Using single mouse data, correlation analyses were performed to determine the relationship among the allergenicity readouts. Spleen cytokines were quantified using a protein microarray method. Our results show that (i) repeated skin exposures to SSPE elicited robust increases in the sIgE and tIgE levels; (ii) skin exposure to SSPE was sufficient to sensitize mice for oral anaphylaxis and MMCR; (iii) both HSR and MMCR showed a strong correlation with each other, as well as with sIgE, and a modest correlation with tIgE levels; (iv) selected Th2/Th17/Th1 cytokines were elevated in skin-sensitized mice; and (v) oral allergen-challenged mice showed selective elevation of IL-6 and a panel of chemokines compared to saline-challenged mice. Together, we report the development and characterization of a novel adjuvant-free wheat-allergy mouse model that uses skin sensitization without tape-stripping followed by oral elicitation of anaphylaxis. Furthermore, validation of quantifiable wheat allergenicity readouts makes this model particularly suitable as a pre-clinical testing tool to assess the intrinsic sensitization/oral-anaphylaxis elicitation potential of novel wheat proteins (e.g., processed wheat) and to develop hypo/non-allergenic wheat products.

A 60-minute dosing interval is safer than a 30- or 40-minute interval in oral food challenge

BACKGROUND

The interval between antigen ingestion may influence the safety of oral food challenge tests (OFCs), especially in patients with severe food allergies.

METHODS

This retrospective chart review of OFCs eliciting objective reactions to wheat, egg, and milk that were performed between April 2012 and January 2021 evaluated an equivalent number of low-dose OFCs performed at 30-, 40-, or 60-min intervals. To avoid the influence of the potential allergy severity of the patients, the prediction scores of all intervals were matched. We evaluated the total symptom score (TS), total ingested dose, and the proportions of severe reactions (TS ≥ 30) and adrenaline use.

RESULTS

We analyzed 945 OFCs (wheat, n = 186; egg, n = 561; milk, n = 198). The 60-min OFC had significantly lower TS than the 30- and 40-min OFC methods in wheat (p < 0.001 and p = 0.003, respectively), egg (p < 0.001 for both), and milk (p < 0.001 and p = 0.018, respectively). The total dose in the 60-min method was significantly lower than in the 30-min method (p < 0.001 for all). The proportion of severe reaction (TS ≥ 30) in the 60-min method was significantly lower than that in the 30-min method for the egg and milk OFCs (p = 0.001 and p < 0.001, respectively). There was no difference in the rates of adrenaline injection.

CONCLUSIONS

The 60-min interval is safer than 30- or 40-min intervals in wheat, egg, and milk OFCs in patients with a low threshold dose for food allergy.

Creating hypo-/nonallergenic wheat products using processing methods: Fact or fiction?

Wheat allergy is a potentiallylife-threatening disease that affects millions of people around the world. Food processing has been shown to influence the allergenicity of wheat and other major foods. However, a comprehensive review evaluating whether or not food processing can be used to develop hypo-/nonallergenic wheat products is unavailable. There were three objectives for this study: (1) to critically evaluate the evidence on the effect of fermentation, thermal processing, and enzyme or acid hydrolysis on wheat allergenicity so as to identify the potential for and challenges of using these methods to produce hypo-/nonallergenic wheat products; (2) to identify the molecular effects of food processing needed to create such products; and (3) to map the concept questions for future research and development to produce hypo-/nonallergenic wheat products. We performed literature research using PubMed and Google Scholar databases with various combinations of keywords to generate the data to accomplish these objectives. We found that: (1) food processing significantly modulates wheat allergenicity; while some methods can reduce or even abolish the allergenicity, others can create mega allergens; and (2) fermentation and enzymatic hydrolysis hold the most potential to create novel hypo-/nonallergenic wheat products; however, preclinical validation and human clinical trials are currently lacking. We also identify five specific research concepts to advance the research to enable the creation of hypo-/nonallergenic wheat products for application in food, medical, and cosmetic industries.

Peanut Can Be Used as a Reference Allergen for Hazard Characterization in Food Allergen Risk Management: A Rapid Evidence Assessment and Meta-Analysis

Regional and national legislation mandates the disclosure of “priority” allergens when present as an ingredient in foods, but this does not extend to the unintended presence of allergens due to shared production facilities. This has resulted in a proliferation of precautionary allergen (“may contain”) labels (PAL) that are frequently ignored by food-allergic consumers. Attempts have been made to improve allergen risk management to better inform the use of PAL, but a lack of consensus has led to variety of regulatory approaches and nonuniformity in the use of PAL by food businesses. One potential solution would be to establish internationally agreed “reference doses,” below which no PAL would be needed. However, if reference doses are to be used to inform the need for PAL, then it is essential to characterize the hazard associated with these low-level exposures. For peanut, there are now published data relating to over 3000 double-blind, placebo-controlled challenges in allergic individuals, but a similar level of evidence is lacking for other priority allergens. We present the results of a rapid evidence assessment and meta-analysis for the risk of anaphylaxis to a low-level allergen exposure for priority allergens. On the basis of this analysis, we propose that peanut can and should be considered an exemplar allergen for the hazard characterization at a low-level allergen exposure.

Pitfalls in the Diagnosis of Coeliac Disease and Gluten-Related Disorders

The spectrum of gluten-related disorders (GRD) has emerged as a relevant phenomenon possibly impacting on health care procedures and costs worldwide. Current classification of GRD is mainly based on their pathophysiology, and the following categories can be distinguished: immune-mediated disorders that include coeliac disease (CD), dermatitis herpetiformis (DH), and gluten ataxia (GA); allergic reactions such as wheat allergy (WA); and non-coeliac gluten sensitivity (NCGS), a condition characterized by both gastrointestinal and extra-intestinal symptoms subjectively believed to be induced by the ingestion of gluten/wheat that has recently gained popularity. Although CD, DH, and WA are well-defined clinical entities, whose diagnosis is based on specific diagnostic criteria, a diagnosis of NCGS may on the contrary be considered only after the exclusion of other organic disorders. Neither allergic nor autoimmune mechanisms have been found to be involved in NCGS. Mistakes in the diagnosis of GRD are still a relevant clinical problem that may result in overtreatment of patients being unnecessary started on a gluten-free diet and waste of health-care resources. On the basis of our clinical experience and literature, we aim to identify the main pitfalls in the diagnosis of CD and its complications, DH, and WA. We provide a practical methodological approach to guide clinicians on how to recognize and avoid them.

Mechanisms of Wheat Allergenicity in Mice: Comparison of Adjuvant-Free vs. Alum-Adjuvant Models

Wheat protein is considered a major type of food allergen in many countries including the USA. The mechanisms of allergenicity of wheat proteins are not well understood at present. Both adjuvant-based and adjuvant-free mouse models are reported for this food allergy. However, it is unclear whether the mechanisms underlying wheat allergenicity in these two types of models are similar or different. Therefore, we compared the molecular mechanisms in a novel adjuvant-free (AF) model vs. a conventional alum-adjuvant (AA) model of wheat allergy using salt-soluble wheat protein (SSWP). In the AF model, Balb/cJ mice were sensitized with SSWP via skin exposure. In the AA model, mice were sensitized by an intraperitoneal injection of SSWP with alum. In both models, allergic reactions were elicited using an identical protocol. Robust IgE as well as mucosal mast cell protein-1 responses were elicited similarly in both models. However, an analysis of the spleen immune markers identified strikingly different molecular activation patterns in these two models. Furthermore, a number of immune markers associated with intrinsic allergenicity were also identified in both models. Since the AF model uses skin exposure without an adjuvant, the mechanisms in the AF model may more closely simulate the human wheat allergenicity mechanisms from skin exposure in occupational settings such as in the baking industry.

Low-dose-oral immunotherapy for children with wheat-induced anaphylaxis

BACKGROUND

Oral immunotherapy (OIT) use in patients with wheat anaphylaxis is not well studied. We assessed the efficacy of low-dose OIT for patients with wheat-induced anaphylaxis.

METHODS

Eligible subjects were aged 5-18 years with a history of wheat anaphylaxis and confirmed symptoms during oral food challenge (OFC) to 53 mg of wheat protein. After admission to the hospital for a 5-day buildup phase, patients in the OIT group gradually increased wheat ingestion to 53 mg/day and then ingested 53 mg daily at home. One year later, they underwent 53- and 400-mg OFCs after OIT cessation for 2 weeks. The historical control group was defined as patients who avoided wheat during the same period.

RESULTS

Median wheat- and ω-5 gliadin-specific immunoglobulin E (sIgE) levels were 293 and 7.5 kU_A /L, respectively, in the OIT group (16 children). No patients dropped out. Within 1 year, 88% of patients in the OIT group reached 53 mg. After 1 year, 69% and 9% patients passed the 53-mg OFC and 25% and 0% passed the 400-mg OFC in the OIT and control groups (11 children), respectively (P = .002 and 0.07, respectively). In the OIT group, wheat- and ω-5 gliadin-sIgE levels significantly decreased to 154 and 4.1 kU_A /L, respectively, at 1 year, and wheat- and ω-5 gliadin-specific IgG and IgG₄ levels significantly increased at 1 month. Anaphylaxis developed 7 times and promptly improved without adrenaline.

CONCLUSION

For patients with wheat anaphylaxis, low-dose OIT safely induces immunologic changes, achieves low-dose desensitization, and may allow for a 400 mg dose.

Oral food challenges: Special considerations

OBJECTIVE

To reinforce special considerations when offering and conducting oral food challenges (OFCs).

DATA SOURCES

Published studies and reviews.

STUDY SELECTIONS

Studies concerning OFCs and their conduct.

RESULTS

Multiple OFC protocols for various clinical situations and foods were reviewed.

CONCLUSION

OFCs are used for the definitive diagnosis of food allergy. Risk and benefit assessment guide the OFC procedure. The conduct of OFCs is influenced by multiple factors, including age, food, and goal of the challenge.

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).

Wheat Allergy in Children: A Comprehensive Update

Gluten-related disorders are very common in pediatric patients. Wheat allergy is triggered by an immunoglobulin E (IgE)-dependent mechanism; its prevalence varies according to the age and region, and in Europe has been estimated to be lower than 1%. Many studies investigated the potential role of several external factors that can influence the risk to developing wheat allergy, but results are still inconclusive. It can be responsible for several clinical manifestations depending on the route of allergen exposure: food-dependent exercise-induced anaphylaxis (FDEIA), occupational rhinitis or asthma (also known as baker’s asthma), and contact urticaria. The prognosis of IgE-mediated wheat allergy in children is generally favorable, with the majority of children becoming tolerant by school age. Patients who experienced an anaphylactic reaction prior to 3 years of age and patients with higher level of wheat- or ω-5 gliadin-specific IgE antibodies seem to be at higher risk of persistent wheat allergy. The current management of patients is dietary avoidance. Nowadays, oral immunotherapy has been proposed for wheat allergy with promising results, even if further studies are necessary to establish the best protocol in order to promote tolerance in wheat-allergic children.

Oral Food Challenge Implementation: The First Mixed-Methods Study Exploring Barriers and Solutions

BACKGROUND

Because of inaccuracies in commonly used tests for food allergy, oral food challenges (OFCs) are considered the criterion standard, but OFC implementation is suboptimal.

OBJECTIVE

To use a mixed-methods approach to describe OFC barriers at multiple levels and investigate solutions.

METHODS

Surveys of Canadian allergists, pediatricians, and parents investigated barriers to offering or participating in OFCs, and possible solutions. Parent focus groups were held to understand these barriers and solutions. Allergist offices in British Columbia were contacted via telephone to confirm their OFC practices.

RESULTS

Of 62 responding allergists, 80.6% reported performing OFCs, 72.6% reported lack of resources as an influential barrier, and 72.6% reported that creation of standard guidelines for hospital versus community OFCs would influence them to perform more OFCs. Of 101 responding pediatricians, 51.5% reported having moderate-to-extensive OFC knowledge; these pediatricians were more likely to refer to allergists who performed them (odds ratio, 2.37; 95% CI, 1.06-5.30). Of 27 pediatricians who stated they refer more to allergists who do not perform OFCs, 40.7% reported long wait times as a deterrent. The most common parent barriers from surveys (N = 110) and focus groups (N = 27) were fear and anxiety about the procedure and about experiencing reactions during OFCs, suggesting the need for better information and psychosocial resources.

CONCLUSIONS

Multiple barriers prevent widespread use of OFCs. Efforts targeting OFC training for allergists, education for pediatricians, and standardized guidelines created with clinician and parent input (including consistent OFC information for families and guidance on which OFCs should be performed in-hospital versus the community) are likely to increase OFC acceptance.

A survey of anaphylaxis etiology and treatment

Identifying the causes of anaphylaxis which is an acute, potentially fatal systemic reaction is very important in every community. Treatment strategies and pitfalls should also be determined. We sought to determine the most common triggers of anaphylaxis, clinical manifestations and treatment strategies in Mashhad, northeast of Iran. An observational cross-sectional study was conducted to evaluate all patients with a history of anaphylactic reaction who were referred to University Allergy Clinics between 2006 and 2016 in Mashhad Iran. We used a combination of patient’s clinical history and allergy diagnostic testing including radioallergosorbant test and skin prick test in order to determine the etiology of anaphylaxis. We identified 172 anaphylactic reactions in 70 patients. Median age was 15 years with a range from 6 months to 48 years. The triggers included: foods, 61.4%; drugs, 15.7%; hymenoptera venom, 8.6%; idiopathic, 5.7%; immunotherapy, 4.3% and other etiologies: 5.7%. Nuts and seeds were the most important triggers of food induced anaphylaxis, especially in school children, adolescents and young adults, followed by fruits. However, Cow’s milk and hen’s egg were the main triggers of anaphylaxis in children aged under 2 years. The most common symptoms were cutaneous and cardiovascular. Corticosteroids (94.3%) and/or antihistamines (85.7%) were used most frequently for treatment followed by intravenous fluids (54.3%), whereas epinephrine was only used in 17.1% of the cases. Food related anaphylaxis and other typical triggers of anaphylaxis are age dependent and the risks and triggers change with age. Epinephrine injection should be increased by improving the awareness of physician and medical teams. The study was approved by the Ethics Committee of the Faculty of Medicine of Mashhad University of Medical Sciences (approved number: IR.MUMS.REC.1393.960).

Allergen immunotherapy for food allergy from the Asian perspective: key challenges and opportunities

Introduction: Prevalence of food allergy is rising in different regions of the world. Asia has not been spared from this epidemic, but epidemiological data have revealed a different pattern of food allergens in this continent. Allergen-specific immunotherapy (AIT) for food allergy, which has been revolutionary as the main focus of research in recent years, needs to be adapted for the different populations in Asia. Areas covered: Recent evidence shows increasing popularity and superiority of AIT over strict food avoidance as the cornerstone of food allergy management. Asia is a distinctive continent with specific food allergy triggers, in particular, seafood, and wheat. Peanut, on the contrary, is not a common food allergen in most parts of Asia. The common Asian food allergens, as well as the rapidly developing food-specific AIT in this region will be covered in this article. Expert commentary: Evidence on oral immunotherapy for wheat allergy and preclinical data on shellfish AIT are promising. Further work should be done on resolving cross-sensitization between environmental allergens with wheat and shellfish allergens, and a modified AIT approach to enhance the safety and effectiveness of food-specific immunotherapy.

Analysis of a Large Standardized Food Challenge Data Set to Determine Predictors of Positive Outcome Across Multiple Allergens

Background: Double-blind placebo-controlled food challenges (DBPCFCs) remain the gold standard for the diagnosis of food allergy; however, challenges require significant time and resources and place the patient at an increased risk for severe allergic adverse events. There have been continued efforts to identify alternative diagnostic methods to replace or minimize the need for oral food challenges (OFCs) in the diagnosis of food allergy.

Methods: Data was extracted for all IRB-approved, Stanford-initiated clinical protocols involving standardized screening OFCs to a cumulative dose of 500 mg protein to any of 11 food allergens in participants with elevated skin prick test (SPT) and/or specific IgE (sIgE) values to the challenged food across 7 sites. Baseline population characteristics, biomarkers, and challenge outcomes were analyzed to develop diagnostic criteria predictive of positive OFCs across multiple allergens in our multi-allergic cohorts.

Results: A total of 1247 OFCs completed by 427 participants were analyzed in this cohort. Eighty-five percent of all OFCs had positive challenges. A history of atopic dermatitis and multiple food allergies were significantly associated with a higher risk of positive OFCs. The majority of food-specific SPT, sIgE, and sIgE/total IgE (tIgE) thresholds calculated from cumulative tolerated dose (CTD)-dependent receiver operator curves (ROC) had high discrimination of OFC outcome (area under the curves > 0.75). Participants with values above the thresholds were more likely to have positive challenges.

Conclusions: This is the first study, to our knowledge, to not only adjust for tolerated allergen dose in predicting OFC outcome, but to also use this method to establish biomarker thresholds. The presented findings suggest that readily obtainable biomarker values and patient demographics may be of use in the prediction of OFC outcome and food allergy. In the subset of patients with SPT or sIgE values above the thresholds, values appear highly predictive of a positive OFC and true food allergy. While these values are relatively high, they may serve as an appropriate substitute for food challenges in clinical and research settings.

Diagnosis of fish and shellfish allergies

Seafood allergy is a hypersensitive disorder with increasing prevalence worldwide. Effective and accurate diagnostic workup for seafood allergy is essential for clinicians and patients. Parvalbumin and tropomyosin are the most common fish and shellfish allergens, respectively. The diagnosis of seafood allergies is complicated by cross-reactivity among fish allergens and between shellfish allergens and other arthropods. Current clinical diagnosis of seafood allergy is a complex algorithm that includes clinical assessment, skin prick test, specific IgE measurement, and oral food challenges. Emerging diagnostic strategies, such as component-resolved diagnosis (CRD), which uses single allergenic components for assessment of epitope specific IgE, can provide critical information in predicting individualized sensitization patterns and risk of severe allergic reactions. Further understanding of the molecular identities and characteristics of seafood allergens can advance the development of CRD and lead to more precise diagnosis and improved clinical management of seafood allergies.

Eliciting Dose and Safety Outcomes From a Large Dataset of Standardized Multiple Food Challenges

Background: Food allergy prevalence has continued to rise over the past decade. While studies have reported threshold doses for multiple foods, large-scale multi-food allergen studies are lacking. Our goal was to identify threshold dose distributions and predictors of severe reactions during blinded oral food challenges (OFCs) in multi-food allergic patients. Methods: A retrospective chart review was performed on all Stanford-initiated clinical protocols involving standardized screening OFCs to any of 11 food allergens at 7 sites. Interval-censoring survival analysis was used to calculate eliciting dose (ED) curves for each food. Changes in severity and ED were also analyzed among participants who had repeated challenges to the same food. Results: Of 428 participants, 410 (96%) had at least one positive challenge (1445 standardized OFCs with 1054 total positive challenges). Participants undergoing peanut challenges had the highest ED₅₀ (29.9 mg), while those challenged with egg or pistachio had the lowest (7.07 or 1.7 mg, respectively). The most common adverse event was skin related (54%), followed by gastrointestinal (GI) events (33%). A history of asthma was associated with a significantly higher risk of a severe reaction (hazard ratio [HR]: 2.37, 95% confidence interval [CI]: 1.36, 4.13). Higher values of allergen-specific IgE (sIgE) and sIgE to total IgE ratio (sIgEr) were also associated with higher risk of a severe reaction (1.49 [1.19, 1.85] and 1.84 [1.30, 2.59], respectively). Participants undergoing cashew, peanut, pecan, sesame, and walnut challenges had more severe reactions as ED increased. In participants who underwent repeat challenges, the ED did not change (p = 0.66), but reactions were more severe (p = 0.02). Conclusions: Participants with a history of asthma, high sIgEr, and/or high values of sIgE were found to be at higher risk for severe reactions during food challenges. These findings may help to optimize food challenge dosing schemes in multi-food allergic, atopic patients, specifically at lower doses where the majority of reactions occur. Trials Registration Number: ClinicalTrials. gov number NCT03539692; https://clinicaltrials.gov/ct2/show/NCT03539692.

Food-Induced Anaphylaxis: an Update

PURPOSE OF REVIEW

This review aims to provide an update of recent advances in the epidemiology, clinical features and diagnosis, and management of food-induced anaphylaxis (FIA).

RECENT FINDINGS

Food allergy prevalence and FIA rates continue to rise, but FIA fatalities are stable. Basophil and mast cell activation tests promise more accurate identification of food triggers. Oral, sublingual, and epicutaneous immunotherapy can desensitize a significant portion of subjects. Epinephrine use for FIA remains sub-optimal. As the burden of food allergy continues to increase, it appears that the corresponding increase in research focused on this epidemic is beginning to bear fruit. The stable number of FIA fatalities in the face of an ongoing epidemic indicates lives have already been saved. The emergence of new diagnostic tests and interventional therapies may transform the management of FIA in the coming years.

Immunotherapy for IgE-mediated wheat allergy

Among various routes of immunotherapy for food allergy, oral immunotherapy (OIT) appears to have a promising result due to its ability to modify abnormal immunologic mechanism of IgE-mediated food allergy. Other methods for immunomodulation such as sublingual (SLIT) or epicutaneous (EPIT) immunotherapy which carry lower rates of systemic reactions, may have less efficacy. Wheat has recently been recognized as a more common cause of food-induced anaphylaxis than previously recognized, especially among young children, around the world. In wheat allergic patients, avoidance recommended as standard recommendation is not easy to follow, because wheat has been used as a common constituents in various kinds of consumed foods in every day's life. Therefore, wheat OIT may be considered as an alternative treatments of those in which wheat avoidance is not sufficient to avert frequent events of anaphylaxis resulting from inadvertent exposure to small amount of wheat among this population. Currently, only few clinical trials about wheat OIT are available. In this review, we discuss available protocols of wheat OIT, initial starting dose, maintenance dose, and the strategies to minimize the side effects during the treatment.

Wheat oral immunotherapy was moderately successful but was associated with very frequent adverse events in children aged 6-18 years

AIM

This study investigated oral immunotherapy (OIT) for children aged 6-18 years with wheat allergies.

METHODS

Well-cooked wheat spaghetti was given to 100 children with wheat allergies every day for 17 weeks, increasing from 0.3 to 2000 mg of wheat protein, followed by three- and nine-month maintenance phases. Blood samples were taken before therapy and at follow-up visits. The study was carried out in 2009-2015 in four Finnish paediatric allergology units.

RESULTS

The children (67% male) had a mean age of 11.6 years (range 6.1-18.6), and 57 were using wheat daily 16 months after the initiation of therapy. Allergic symptoms occurred in 94/100 children: mild in 34, moderate in 36 and severe in 24. Specific immunoglobulin E (IgE) for ω-5-gliadin was significantly higher in patients who did not reach the target dose and were related to the intensity of reactions.

CONCLUSION

The majority (57%) of children with wheat allergies could use wheat in their daily diet 16 months after the initiation of OIT, but 94/100 had adverse reactions and 60 were moderate or severe. Specific IgE to ω-5-gliadin may provide a biomarker for how much wheat can be tolerated and the intensity of the reactions to immunotherapy.

Development of a tool predicting severity of allergic reaction during peanut challenge

BACKGROUND

Reliable prognostic markers for predicting severity of allergic reactions during oral food challenges (OFCs) have not been established.

OBJECTIVE

To develop a predictive algorithm of a food challenge severity score (CSS) to identify those at higher risk for severe reactions to a standardized peanut OFC.

METHODS

Medical history and allergy test results were obtained for 120 peanut allergic participants who underwent double-blind, placebo-controlled food challenges. Reactions were assigned a CSS between 1 and 6 based on cumulative tolerated dose and a severity clinical indicator. Demographic characteristics, clinical features, peanut component IgE values, and a basophil activation marker were considered in a multistep analysis to derive a flexible decision rule to understand risk during peanut of OFC.

RESULTS

A total of 18.3% participants had a severe reaction (CSS >4). The decision rule identified the following 3 variables (in order of importance) as predictors of reaction severity: ratio of percentage of CD63^hi stimulation with peanut to percentage of CD63^hi anti-IgE (CD63 ratio), history of exercise-induced asthma, and ratio of forced expiratory volume in 1 second to forced vital capacity (FEV₁/FVC) ratio. The CD63 ratio alone was a strong predictor of CSS (P < .001).

CONCLUSION

The CSS is a novel tool that combines dose thresholds and allergic reactions to understand risks associated with peanut OFCs. Laboratory values (CD63 ratio), along with clinical variables (exercise-induced asthma and FEV₁/FVC ratio) contribute to the predictive ability of the severity of reaction to peanut OFCs. Further testing of this decision rule is needed in a larger external data source before it can be considered outside research settings.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02103270.

Evaluation of a new protocol for wheat desensitization in patients with wheat-induced anaphylaxis

AIM

New approaches such as oral immunotherapy (OIT) may be useful in IgE-mediated anaphylaxis to wheat.

PATIENTS & METHODS

12 patients underwent OIT protocol that comprised of two phases: the first with semolina flour and the second with spaghetti. Total and specific wheat IgE were assayed by ELISA before and after OIT and 18 months later. Skin prick tests were also performed.

RESULTS

Patients successfully tolerated 50 g of wheat. The median baseline total IgE was decreased after up-dosing phase and decreased after follow-up (p < 0.01). The median baseline wheat-specific IgE was increased after up-dosing and decreased after follow-up (p < 0.001).

CONCLUSION

The efficiency and safety of our OIT protocol were shown on wheat allergic patients but further investigation is needed.

An unusual case of infant seizures with anaphylaxis to wheat

Wheat allergy is one of the commonest food allergies in childhood and it typically presents with IgE mediated reactions, including anaphylaxis. Seizures are not typically reported to be a direct manifestation of anaphylaxis, though it can occur secondary to hypoxia following significant haemodynamic compromise. We describe a case of a previously well infant, who presented with anaphylactic shock to wheat and responded well to the initial management, but subsequently developed a cluster of brief generalised tonic clonic seizures without any ongoing haemodynamic instability. The tryptase level that was performed at 4-5 hours post reaction was raised at 49.1 µg/L. Skin prick test to wheat, wheat specific IgE, the omega-5 gliadin IgE were positive. Extensive work-up was performed to look for an underlying cause of seizures and all returned negative. To our knowledge, this is the first case report describing an unusual presentation of multiple seizures in a young infant, in association with an anaphylactic episode. In the absence of any other seizure provoking factor and underlying cause, we believe the association is more likely causative than coincidental.

Risk Factors for Severe Reactions during Double-Blind Placebo-Controlled Food Challenges

BACKGROUND

Severe anaphylactic symptoms can occur during oral food challenges (OFCs). Thus, high-risk patients (e.g., patients with a history of anaphylaxis or high antigen-specific immunoglobulin E [IgE] levels) must carefully undergo OFCs in hospitals. We attempted to identify the risk factors for severe symptoms during OFC testing among high-risk patients.

METHODS

We retrospectively evaluated patients' characteristics and severe symptoms that were experienced during a double-blind placebo-controlled food challenge test performed before the patients underwent oral immunotherapy between June 2008 and June 2012. Patients were ≥5 years old and had an anaphylactic history or antigen-specific IgE (>30 kUA/L). Severe symptoms were defined using the grading of the Japanese Anaphylaxis Guidelines, which are modified from the European Academy of Allergology and Clinical Immunology Guidelines.

RESULTS

We evaluated 393 cases with positive test results, including 98 cases with severe symptoms. The most frequent severe symptoms were respiratory (77%), gastrointestinal (28%), cardiovascular (27%), and neurological (13%) symptoms. Multivariate analysis revealed that the significant factors for a severe reaction were a history of anaphylaxis to the causative food (adjusted odds ratio [OR]: 2.147, p = 0.003), older age (per 1 year increase, adjusted OR: 1.102, p = 0.044), and an egg OFC (adjusted OR: 0.433, p = 0.003).

CONCLUSIONS

The risk factors for a severe reaction to OFCs were a history of an anaphylactic reaction and older age. An egg OFC was associated with low risk of severe symptoms during OFC. Therefore, OFCs for patients with these risk factors should only be performed under specialist supervision with access to rapid treatment and full resuscitation equipment.

Reactions of Buckwheat-Hypersensitive Patients during Oral Food Challenge Are Rare, but Often Anaphylactic

BACKGROUND

Buckwheat (BW) is a common cause of life-threatening allergy in Asia. Few have examined oral food challenges (OFCs) using BW. We here describe the OFC outcomes for the diagnosis or confirmation of tolerance acquisition and clarify risk factors for positive OFCs.

METHODS

Between July 2005 and March 2014, we retrospectively reviewed data from children who underwent OFCs using 3,072 mg of BW protein at Sagamihara National Hospital. Children were suspected of having BW allergy because of positive results for BW-specific IgE or because they had been previously diagnosed with BW allergy owing to immediate reactions to BW.

RESULTS

Of 476 such patients, we analyzed 419 aged 1-17 years (median age 6.7 years). Forty-four (10.5%) reacted to the BW OFC and 24 (54.5%) experienced anaphylaxis. Among patients with suspected BW allergies (n = 369), 30 (8.1%) reacted to OFC. However, among patients with definitive BW allergies (n = 50) who underwent OFCs a median of 7.0 years after their last immediate reaction, 14 (28.0%) reacted to OFC. Among 12 patients with past anaphylactic reactions to BW, 8 exhibited tolerance to BW. A history of immediate reaction to BW and high BW-specific IgE levels were significant risk factors for a positive OFC.

CONCLUSIONS

BW allergies are rare among children suspected of having BW allergies due to positivity for BW-specific IgE. Most children with definitive BW allergies can tolerate BW, even after anaphylactic reactions. Nevertheless, careful observation is needed when performing BW OFCs, considering the high incidence of anaphylactic reactions.

The intestinal barrier as an emerging target in the toxicological assessment of mycotoxins

Mycotoxins, the secondary metabolites of fungal species, are the most frequently occurring natural food contaminants in human and animal diets. Risk assessment of mycotoxins focused as yet on their mutagenic, genotoxic and potential carcinogenic effects. Recently, there is an increasing awareness of the adverse effects of various mycotoxins on vulnerable structures in the intestines. In particular, an impairment of the barrier function of the epithelial lining cells and the sealing tight junction proteins has been noted, as this could result in an increased translocation of luminal antigens and pathogens and an excessive activation of the immune system. The current review aims to provide a summary of the available evidence regarding direct effects of various mycotoxins on the intestinal epithelial barrier. Available data, based on different cellular and animal studies, show that food-associated exposure to certain mycotoxins, especially trichothecenes and patulin, affects the intestinal barrier integrity and can result in an increased translocation of harmful stressors. It is therefore hypothesized that human exposure to certain mycotoxins, particularly deoxynivalenol, as the major trichothecene, may play an important role in etiology of various chronic intestinal inflammatory diseases, such as inflammatory bowel disease, and in the prevalence of food allergies, particularly in children.

Risk and safety requirements for diagnostic and therapeutic procedures in allergology: World Allergy Organization Statement

One of the major concerns in the practice of allergy is related to the safety of procedures for the diagnosis and treatment of allergic disease. Management (diagnosis and treatment) of hypersensitivity disorders involves often intentional exposure to potentially allergenic substances (during skin testing), deliberate induction in the office of allergic symptoms to offending compounds (provocation tests) or intentional application of potentially dangerous substances (allergy vaccine) to sensitized patients. These situations may be associated with a significant risk of unwanted, excessive or even dangerous reactions, which in many instances cannot be completely avoided. However, adverse reactions can be minimized or even avoided if a physician is fully aware of potential risk and is prepared to appropriately handle the situation. Information on the risk of diagnostic and therapeutic procedures in allergic diseases has been accumulated in the medical literature for decades; however, except for allergen specific immunotherapy, it has never been presented in a systematic fashion. Up to now no single document addressed the risk of the most commonly used medical procedures in the allergy office nor attempted to present general requirements necessary to assure the safety of these procedures. Following review of available literature a group of allergy experts within the World Allergy Organization (WAO), representing various continents and areas of allergy expertise, presents this report on risk associated with diagnostic and therapeutic procedures in allergology and proposes a consensus on safety requirements for performing procedures in allergy offices. Optimal safety measures including appropriate location, type and required time of supervision, availability of safety equipment, access to specialized emergency services, etc. for various procedures have been recommended. This document should be useful for allergists with already established practices and experience as well as to other specialists taking care of patients with allergies.

Wheat allergy: diagnosis and management

Triticum aestivum (bread wheat) is the most widely grown crop worldwide. In genetically predisposed individuals, wheat can cause specific immune responses. A food allergy to wheat is characterized by T helper type 2 activation which can result in immunoglobulin E (IgE) and non-IgE mediated reactions. IgE mediated reactions are immediate, are characterized by the presence of wheat-specific IgE antibodies, and can be life-threatening. Non-IgE mediated reactions are characterized by chronic eosinophilic and lymphocytic infiltration of the gastrointestinal tract. IgE mediated responses to wheat can be related to wheat ingestion (food allergy) or wheat inhalation (respiratory allergy). A food allergy to wheat is more common in children and can be associated with a severe reaction such as anaphylaxis and wheat-dependent, exercise-induced anaphylaxis. An inhalation induced IgE mediated wheat allergy can cause baker’s asthma or rhinitis, which are common occupational diseases in workers who have significant repetitive exposure to wheat flour, such as bakers. Non-IgE mediated food allergy reactions to wheat are mainly eosinophilic esophagitis (EoE) or eosinophilic gastritis (EG), which are both characterized by chronic eosinophilic inflammation. EG is a systemic disease, and is associated with severe inflammation that requires oral steroids to resolve. EoE is a less severe disease, which can lead to complications in feeding intolerance and fibrosis. In both EoE and EG, wheat allergy diagnosis is based on both an elimination diet preceded by a tissue biopsy obtained by esophagogastroduodenoscopy in order to show the effectiveness of the diet. Diagnosis of IgE mediated wheat allergy is based on the medical history, the detection of specific IgE to wheat, and oral food challenges. Currently, the main treatment of a wheat allergy is based on avoidance of wheat altogether. However, in the near future immunotherapy may represent a valid way to treat IgE mediated reactions to wheat.

Better management of wheat allergy using a very low-dose food challenge: A retrospective study

BACKGROUND

Low-dose reactive wheat-allergic children are at a high risk of a positive oral food challenge (OFC). The present study aimed to evaluate whether the results of a very low-dose (VL) OFC would contribute to better wheat allergy management in this population.

METHODS

We retrospectively reviewed wheat-allergic subjects who underwent a VL OFC with 2 g of udon noodles (equivalent to 53 mg of wheat protein) and had a previous allergic reaction to <15 g of udon noodles (equivalent to 400 mg of wheat protein) within 2 years before the OFC. Subjects who passed the OFC were defined as VL tolerant; those who failed were considered VL reactive. In VL tolerant subjects, the dose was increased to 15 g of udon noodles either during an OFC in our hospital or gradually at home.

RESULTS

Of the 57 included subjects (median age, 2.9 years; range, 1.0-11.8 years), 32 (56%) were VL tolerant and 25 (44%) were VL reactive. Most reactions during the OFC could be treated with an antihistamine and/or a nebulized β2 agonist. VL tolerant subjects consumed 2 g of udon noodles or a seasoning containing wheat. Within a year after the OFC, 18 VL tolerant subjects (56%), but no VL reactive subjects, were able to consume 15 g of udon noodles (p < 0.001).

CONCLUSIONS

A VL OFC can shift the management of some low-dose reactive wheat-allergic children from complete avoidance to partial wheat intake.

Egg Food Challenges are Associated with More Gastrointestinal Reactions

Egg allergy is a common pediatric allergy, and is usually outgrown by elementary school age. There is, therefore, a need to perform an oral food challenge (OFC) to establish the presence of food allergy to egg. In this study, we conducted a retrospective review of 2304 OFCs at a pediatric center and analyzed the severity of reactions during egg OFCs and compared them with other foods. The gastrointestinal system (GI) has been reported as more affected in egg food challenge. This study confirmed that 11% of patients undergoing egg OFC had GI symptoms vs. 7% undergoing food challenges for other foods or compared to milk, peanut and tree nut, individually. However, the involvement of lower respiratory tract was less frequent with egg than observed in peanut and tree nut OFC and similar to observed rate in milk. In conclusion, our study confirmed that OFC to egg causes more GI symptoms and less respiratory symptoms compared to other foods, in particular peanuts and tree nuts. However, 27% of children who failed egg OFC had lower respiratory tract reactions and required the use of epinephrine, similarly to children undergoing milk challenge.

Delayed clinical and ex vivo response to mammalian meat in patients with IgE to galactose-alpha-1,3-galactose

BACKGROUND

In 2009, we reported a novel form of delayed anaphylaxis to red meat related to serum IgE antibodies to the oligosaccharide galactose-alpha-1,3-galactose (alpha-gal). Although patients were remarkably consistent in their description of a 3- to 6-hour delay between eating mammalian meat and the appearance of symptoms, this delay has not been demonstrated under observed studies.

OBJECTIVES

We sought to formally document the time course of clinical symptoms after the ingestion of mammalian meat in subjects with IgE to alpha-gal and to monitor ex vivo for the appearance of markers of an allergic reaction.

METHODS

Open food challenges were performed with mammalian meat in 12 subjects with a history of severe urticarial reactions 3 to 6 hours after eating beef, pork, or lamb, as well as in 13 control subjects. Blood samples were taken hourly during each challenge.

RESULTS

Ten of 12 subjects with IgE to alpha-gal had clinical evidence of a reaction during the food challenge (vs none of the control subjects, P < .001). The reactions occurred 3 to 7 hours after the initial ingestion of mammalian meat and ranged from urticaria to anaphylaxis. Tryptase levels were positive in 3 challenges. Basophil activation, as measured by increased expression of CD63, correlated with the appearance of clinical symptoms.

CONCLUSION

The results presented provide clear evidence of an IgE-mediated food allergy that occurs several hours after ingestion of the inciting allergen. Moreover, here we report that in vivo basophil activation during a food challenge occurs in the same time frame as clinical symptoms and likely reflects the appearance of the antigen in the bloodstream.