Food allergy. Part 2: diagnosis and management

The ethics of food allergy

PURPOSE OF REVIEW

Ethical dilemmas are a common occurrence in the provision of care to individuals with food allergies. Thus, an understanding of medical ethics is essential for allergists/immunologists.

RECENT FINDINGS

Despite the importance of medical ethics in the clinical practice of food allergy, there has been little published on this topic. Some international allergy societies have published ethical guidelines. Further investigation on medical ethics in food allergy is required.

SUMMARY

This review describes key ethical principles in relation to food allergy testing, oral food challenges, and various management strategies, including avoidance, omalizumab and oral immunotherapy. This review demonstrates the necessity for education and research on medical ethics in food allergy.

IgE-Crosslinking-Induced Luciferase Expression Test as a Sensitive Indicator of Anisakis Allergy

Background:Anisakis allergy has been increasing, and the diagnosis of it is based on specific serum IgE detection. Recently, the IgE-crosslinking-induced luciferase expression (EXiLE) test has been proposed as convenient tool for detecting functionally specific IgE antibodies. Here, we investigated if the EXiLE test is a useful tool in the diagnosis of Anisakis allergy. Methods: HuRa-40 cells were sensitized using six serum types from three patients with Anisakis allergy at the time of the initial test and after 6-12 months. Thereafter, various concentrations of Anisakis worm protein (AWP) were reacted to measure the degree of EXiLE. The degree of EXiLE was compared with Anisakis-specific IgE antibody levels measured by the CAP-FEIA method, and the IgE-antibody-binding protein profile was examined using IgE immunoblotting. Results: The results showed a good correlation between the CAP-FEIA values and EXiLE obtained with 5 μg/mL of AWP (R = 0.91, p < 0.01), a strong response on IgE immunoblotting in the region containing proteins weighing ≥40,000 Da. In addition, after the onset of Anisakis allergy, the degree of serum EXiLE decreased in two patients whose Anisakis-specific IgE antibody levels decreased over time but increased in one patient whose specific IgE antibodies increased after repeated antigen sensitization. Conclusions: Based on these data, the AWP-induced EXiLE test seemed to be useful and convenient for the diagnosis of Anisakis allergy, supplementing specific IgE determinants. After allergy onset, the use of this method to observe changes in specific IgE levels over time may be important for predicting the risk of recurrence.

Pearls and Pitfalls of Weaning an Infant with Severe Atopic Dermatitis and Sensitization/Allergy to Food

Atopic dermatitis (AD) is a common chronic inflammatory skin disorder in childhood. Skin barrier impairment exposes infants to food allergens, potentially causing sensitization followed by IgE-mediated food allergy. We describe the case of an infant with severe AD in whom several sensitizations to foods are detected, with consequently difficult weaning, and a history of anaphylaxis to cashew nut. Foods for which skin tests were negative were introduced into the infant's diet. Then, when AD control was managed, oral food challenges (OFCs) for foods to which the patient was sensitized, with the exception of cashew nut, were performed. The simultaneous presence of sensitization toward multiple foods made it difficult to introduce them using classic OFC. Therefore, it was decided to perform the low-dose, gradual controlled OFC. This led to an introduction of sensitized foods into the infant's diet, with the exception of cashew nut, avoiding allergic reactions. Absolute recommendations on how, when, and where to perform OFCs with allergenic food to which the child with AD is sensitized are lacking so far. In our opinion, OFCs and the subsequent ntroduction of allergenic foods should be individualized, evaluating some factors such as their social and nutritional importance, the patient's age and clinical phenotype (including the history of anaphylaxis), and the sensitization profile. There is agreement on the fact that the dietary approach in children with moderate-severe AD should no longer include a strict elimination diet. We believe that an early, gradual controlled introduction of all allergenics to identify the amount of food tolerated in the absence of reactions, even if low dose, may improve patients' and families' quality of life. However, even if discussing a vast relevant literature, the limitation of our work is that we describe the management of a single patient. Extensive and high-quality research is needed in this field to improve the available evidence in the area.

Food allergy in children-the current status and the way forward

Food allergy in children is a major health concern, and its prevalence is rising. It is often over-diagnosed by parents, resulting occasionally in unnecessary exclusion of some important food. It also causes stress, anxiety, and even depression in parents and affects the family's quality of life. Current diagnostic tests are useful when interpreted in the context of the clinical history, although cross-sensitivity and inability to predict the severity of the allergic reactions remain major limitations. Although the oral food challenge is the current gold standard for making the diagnosis, it is only available to a small number of patients because of its requirement in time and medical personnel. New diagnostic methods have recently emerged, such as the Component Resolved Diagnostics and the Basophil Activation Test, but their use is still limited, and the latter lacks standardisation. Currently, there is no definite treatment available to induce life-long natural tolerance and cure for food allergy. Presently available treatments only aim to decrease the occurrence of anaphylaxis by enabling the child to tolerate small amounts of the offending food, usually taken by accident. New evidence supports the early introduction of the allergenic food to infants to decrease the incidence of food allergy. If standardised and widely implemented, this may result in decreasing the prevalence of food allergy.

Oral Immunotherapy in Food Allergy: A Critical Pediatric Perspective

There is evidence that in children with persistent IgE-mediated food allergy (FA) to cow's milk, hen's egg, and peanut, oral allergen-specific immunotherapy (OIT) may increase the reaction threshold to the culprit food allergen(s). OIT may protect patients from the occurrence of severe reactions in case of accidental ingestion of the culprit food during treatment. Notwithstanding, many gaps are still unsolved, including safety issues, identification of predictive biomarkers, and post-desensitization efficacy. In this perspective, the use of omalizumab (Anti-IgE monoclonal antibody) has been proposed as an adjunctive treatment to OIT in order to reduce the risk of allergic reactions related to OIT. This review aims to summarize the current evidence and unmet needs on OIT in children with FA to enhance the development of longitudinal, prospective, and well-designed studies able to fill the current gaps soon.

Immunologic and pathologic characterization of a novel swine biomedical research model for eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a chronic allergy-mediated condition with an increasing incidence in both children and adults. Despite EoE's strong impact on human health and welfare, there is a large unmet need for treatments with only one recently FDA-approved medication for EoE. The goal of this study was to establish swine as a relevant large animal model for translational biomedical research in EoE with the potential to facilitate development of therapeutics. We recently showed that after intraperitoneal sensitization and oral challenge with the food allergen hen egg white protein (HEWP), swine develop esophageal eosinophilia-a hallmark of human EoE. Herein, we used a similar sensitization and challenge treatment and evaluated immunological and pathological markers associated with human EoE. Our data demonstrate that the incorporated sensitization and challenge treatment induces (i) a systemic T-helper 2 and IgE response, (ii) a local expression of eotaxin-1 and other allergy-related immune markers, (iii) esophageal eosinophilia (>15 eosinophils/0.24 mm²), and (iv) esophageal endoscopic findings including linear furrows and white exudates. Thereby, we demonstrate that our sensitization and oral challenge protocol not only induces the underlying immune markers but also the micro- and macro-pathological hallmarks of human EoE. This swine model for EoE represents a novel relevant large animal model that can drive translational biomedical research to develop urgently needed treatment strategies for EoE.

White paper on peanut allergy - part 1: Epidemiology, burden of disease, health economic aspects

Peanuts are Leguminosae, commonly known as the legume or pea family, and peanut allergy is among the most common food allergies and the most common cause of fatal food reactions and anaphylaxis.

The prevalence of peanut allergy increased 3.5-fold over the past two decades reaching 1.4–2% in Europe and the United States. The reasons for this increase in prevalence are likely multifaceted. Sensitization via the skin appears to be associated with the development of peanut allergy and atopic eczema in infancy is associated with a high risk of developing peanut allergy.

Until recently, the only possible management strategy for peanut allergy was strict allergen avoidance and emergency treatment including adrenaline auto-injector in cases of accidental exposure and reaction.

This paper discusses the various factors that impact the risks of peanut allergy and the burden of self-management on peanut-allergic children and their caregivers.

Tackling Food Allergy in Infancy

Atopic dermatitis and food allergy are the most common allergic conditions affecting the infant population. Both immunoglobulin E (IgE)-mediated and non-IgE-mediated food allergy are seen in infancy. Early life feeding guidelines have changed dramatically over the past 30 years, more recently because of an improved understanding of IgE-mediated food allergy. This article focuses on identification, diagnosis, management, and prevention of food allergy in the infant population.

Potential allergenicity of Medicago sativa investigated by a combined IgE-binding inhibition, proteomics and in silico approach

BACKGROUND

Alfalfa (Medicago sativa L) is one of the most planted crops worldwide primarily used to feed animals. The use of alfalfa in human diet as sprouts, infusions and nutritional supplements is rapidly gaining popularity. Despite this, allergenicity assessment of this novel plant food is largely lacking.

RESULTS

Here, leaf protein extract of alfalfa was studied using a combined proteomics, Immunoglobulin E (IgE)-binding inhibition assay and in silico approach to find potential allergens. We have identified and annotated 129 proteins using in-gel digestion proteomics and Blast2Go suit. A search against COMPARE database, using the identified proteins as query sequences, revealed high similarity with several allergenic proteins. The Single Point Highest Inhibition Achievable assay (SPHIAa) performed on the multiplex FABER^® allergy testing system confirmed the in silico results and showed some additional potential allergens. This approach allowed the detection of proteins in alfalfa leaves cross-reacting with plant allergens from three different allergen families such as lipid transfer, thaumatin-like and Bet v 1-like protein families. In addition, the absence of structural determinants cross-reacting with seed storage allergenic proteins and with animal allergens was recorded.

CONCLUSION

This study reports for the first time potential allergenic proteins in alfalfa. The results suggest that this plant food can be safely introduced, as a protein-rich supplement, in the diet of patients allergic to animal food allergens. Allergic patients towards certain plant food allergens need to be careful about consuming alfalfa because they might have allergic symptoms. © 2020 Society of Chemical Industry.

Novel Allergen Discovery through Comprehensive De Novo Transcriptomic Analyses of Five Shrimp Species

Shellfish allergy affects 2% of the world's population and persists for life in most patients. The diagnosis of shellfish allergy, in particular shrimp, is challenging due to the similarity of allergenic proteins from other invertebrates. Despite the clinical importance of immunological cross-reactivity among shellfish species and between allergenic invertebrates such as dust mites, the underlying molecular basis is not well understood. Here we mine the complete transcriptome of five frequently consumed shrimp species to identify and compare allergens with all known allergen sources. The transcriptomes were assembled de novo, using Trinity, from raw RNA-Seq data of the whiteleg shrimp (Litopenaeus vannamei), black tiger shrimp (Penaeus monodon), banana shrimp (Fenneropenaeus merguiensis), king shrimp (Melicertus latisulcatus), and endeavour shrimp (Metapenaeus endeavouri). BLAST searching using the two major allergen databases, WHO/IUIS Allergen Nomenclature and AllergenOnline, successfully identified all seven known crustacean allergens. The analyses revealed up to 39 unreported allergens in the different shrimp species, including heat shock protein (HSP), alpha-tubulin, chymotrypsin, cyclophilin, beta-enolase, aldolase A, and glyceraldehyde-3-phosphate dehydrogenase (G3PD). Multiple sequence alignment (Clustal Omega) demonstrated high homology with allergens from other invertebrates including mites and cockroaches. This first transcriptomic analyses of allergens in a major food source provides a valuable resource for investigating shellfish allergens, comparing invertebrate allergens and future development of improved diagnostics for food allergy.

Eosinophilic Esophagitis as a Side Effect of Food Oral Immunotherapy

Food allergies (FAs) include a spectrum of immune-mediated serious and potentially life-threatening medical conditions with an overall estimated prevalence ranging from 4% to 8% in the U.S. and Europe. Significant progress in food allergen-specific immunotherapy has been accomplished over the past 10 years. The most studied strategy has been oral immunotherapy (OIT), also known as food desensitization, a treatment in which a child is slowly and deliberately given a small amount of the food to ingest (that previously was a food allergy trigger) with the ultimate goal of the child eating that food without a reaction. OIT is now recommended in the European guidelines for the treatment of milk, egg, and peanut allergies and was the first American Food Drug Administration (FDA) approved product for the prevention of severe reaction to peanuts in 4–17 year olds to be released on the market. The side effects associated with OIT treatment trials are mild to moderate, predominantly oropharyngeal, and easily treated. More severe reactions, such as generalized urticaria/angioedema, wheezing/respiratory distress, laryngeal edema, and repetitive emesis, have been reported. However systemic reactions are very rare. Low-dose immunotherapy is associated with significantly fewer side effects. Currently, its most limiting allergic side effect is that approximately 10–15% of subjects treated with OIT experience gastrointestinal symptoms, preventing the continuation of therapy. Eosinophilic esophagitis (EoE) has also been reported as a cause of persistent abdominal symptoms in OIT.

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.

Rhinitis 2020: A practice parameter update

This comprehensive practice parameter for allergic rhinitis (AR) and nonallergic rhinitis (NAR) provides updated guidance on diagnosis, assessment, selection of monotherapy and combination pharmacologic options, and allergen immunotherapy for AR. Newer information about local AR is reviewed. Cough is emphasized as a common symptom in both AR and NAR. Food allergy testing is not recommended in the routine evaluation of rhinitis. Intranasal corticosteroids (INCS) remain the preferred monotherapy for persistent AR, but additional studies support the additive benefit of combination treatment with INCS and intranasal antihistamines in both AR and NAR. Either intranasal antihistamines or INCS may be offered as first-line monotherapy for NAR. Montelukast should only be used for AR if there has been an inadequate response or intolerance to alternative therapies. Depot parenteral corticosteroids are not recommended for treatment of AR due to potential risks. While intranasal decongestants generally should be limited to short-term use to prevent rebound congestion, in limited circumstances, patients receiving regimens that include an INCS may be offered, in addition, an intranasal decongestant for up to 4 weeks. Neither acupuncture nor herbal products have adequate studies to support their use for AR. Oral decongestants should be avoided during the first trimester of pregnancy. Recommendations for use of subcutaneous and sublingual tablet allergen immunotherapy in AR are provided. Algorithms based on a combination of evidence and expert opinion are provided to guide in the selection of pharmacologic options for intermittent and persistent AR and NAR.

Distinct Skin Microbiota Imbalance and Responses to Clinical Treatment in Children With Atopic Dermatitis

Background: Atopic dermatitis (AD) is a common cutaneous disease, associated with imbalances in the skin microbiota. Objective: To explore the characteristics of the cutaneous microbiota and its dynamic changes during clinical treatment. Methods: Cutaneous swab samples were collected from 51 AD patients before treatment, and 40 AD patients remained after a 2-week treatment with mometasone and mupirocin. Results: AD patients exhibited significant enrichments of Prevotella and Desulfovibrio as well as obvious reductions of Corynebacterium, Streptococcus and Parabacteroides. Based on the proportion of Staphylococcus aureus, the AD patients were further classified into S. aureus-predominant group (AD.S) and S. aureus-non-dominant (AD.ND) group. The AD.S group exhibited lower skin microbial diversity and higher atopic dermatitis (SCORAD) index. In the AD.S group, the cutaneous microbial diversity significantly increased from 2.9 ± 0.8 to 3.7 ± 1.0, while the relative abundance of S. aureus decreased from 42.5 ± 20.7 to 10.3 ± 28.4 after treatment. In contrast, no significant skin microbiota changes were detected in the AD.ND group. Conclusions: AD patients with predominant S. aureus had higher disease severity and lower microbiota diversity compared to patients in the AD.ND group. Mometasone and mupirocin therapy had significant effects on skin microbiota in AD.S patients, but had a paradoxical response in the AD.ND patients.

Deserters on the atopic march: Risk factors, immune profile and clinical outcomes of food sensitized-tolerant infants

BACKGROUND

A few studies have investigated the antecedents and outcomes of infants who demonstrate IgE sensitization to foods that they clinically tolerate. Improved understanding of this sensitized-tolerant phenotype may inform strategies for the prevention of food allergy.

METHODS

In an Australian birth cohort (n = 1074), assembled using an unselected antenatal sampling frame, participants were categorized as nonsensitized (NS), sensitizedtolerant (ST), or food allergic (FA) based on skin prick testing and food challenge at 12 months of age. Environmental exposures were recorded throughout. Cord blood regulatory T-cell populations were measured at birth. Subsequent childhood allergic disease was assessed by parent report, clinical examination, and repeat skin prick testing.

RESULTS

The covariates of interest varied between NS (n = 698), ST (n = 27), and FA (n = 61) groups as follows, suggesting that across these measures, the ST group was more similar to the NS than the FA group: family history of eczema NS 44.6%, ST. 44.6%, FA 65.6%; pet ownership at 12 months: NS 71.5%, ST 81.5%, FA 45.8%; eczema during the first 12 months: NS 19%, ST 32%, FA 64%; and aeroallergen sensitization at 4 years: NS 19.1%, ST 28.6%, FA 44.4%. At birth, a higher proportion of activated regulatory T cells was associated with ST (OR = 2.89, 95% CI 1.03-8.16, P = .045).

CONCLUSION

Food-sensitized-tolerance in infancy appears to be associated with a similar pattern of exposures, immunity, and outcomes to nonsensitized infants. In addition, we found some evidence that an elevated proportion of activated regulatory T cells at birth was specific to the sensitized-tolerant infants, which may be relevant to suppression of clinical disease.

Food Elimination in the Management of Refractory Chronic Rhinosinusitis: A Pilot Study

BACKGROUND

Chronic rhinosinusitis (CRS) is one of the most commonly reported chronic diseases. Refractory CRS represents a subgroup of patients who continue to be symptomatic even after adequate medical and surgical therapy. These patients started to form a significant portion of patients with CRS. Food elimination as a therapeutic method to control symptoms of different chronic diseases, such as eosinophilic esophagitis, asthma, and atopic dermatitis, has been described in the literature with variable success rates.

OBJECTIVES

To evaluate the effectiveness of food elimination therapy as adjuvant treatment in refractory patients having CRS with positive food sensitization.

DESIGN

Prospective open-label study.

SETTING

Tertiary academic center.

METHODS

Consecutive adult patients with refractory nonobstructive CRS (patients who had persistent sinonasal symptoms despite endoscopic sinus surgery and patent sinuses ostia with adequate medical treatment) with positive food sensitization were included. Subjects were asked to eliminate the sensitized food from their diet. Clinical outcome was assessed using the Lund-Kennedy symptom and Lund-Kennedy endoscopic appearance scores.

RESULTS

Twenty-two patients were initially enrolled in the study. Six patients were excluded; 4 were lost to follow-up, and 2 did not eliminate the causal food for the required period. The average age of the patients was 36 years old. There were 10 female and 6 male patients. Nasal discharge and facial pressure were the most common presenting symptoms. Shellfish, egg, and meat mix were the most common eliminated foods. There was a significant difference in the patients' Lund-Kennedy symptom and Lund-Kennedy endoscopic appearance scores at 6 and 12 weeks after food elimination therapy.

CONCLUSIONS

Food elimination in refractory CRS is an effective adjuvant treatment and should be considered in the treatment algorithm of patients with persistent symptoms after successfully performed sinus surgery.

Oral Food Challenges in Infants and Toddlers

Oral food challenges (OFCs) are an indispensable tool for accurately diagnosing clinically relevant food allergy. Despite perceived concerns, data suggest OFCs, including infant OFCs, are both safe and practical in the clinical setting. The benefits of OFCs can be far reaching and impactful for the patient and parents, with improved quality of life, clarifying unnecessary dietary restrictions, increased social interactions, and reducing fear and anxiety. Demand for OFCs in infants and toddlers will continue to increase in the coming years and board-certified allergists will need to meet these demands by providing appropriate care in a safe and welcoming environment.

IgE allergy diagnostics and other relevant tests in allergy, a World Allergy Organization position paper

Currently, testing for immunoglobulin E (IgE) sensitization is the cornerstone of diagnostic evaluation in suspected allergic conditions. This review provides a thorough and updated critical appraisal of the most frequently used diagnostic tests, both in vivo and in vitro. It discusses skin tests, challenges, and serological and cellular in vitro tests, and provides an overview of indications, advantages and disadvantages of each in conditions such as respiratory, food, venom, drug, and occupational allergy. Skin prick testing remains the first line approach in most instances; the added value of serum specific IgE to whole allergen extracts or components, as well as the role of basophil activation tests, is evaluated. Unproven, non-validated, diagnostic tests are also discussed. Throughout the review, the reader must bear in mind the relevance of differentiating between sensitization and allergy; the latter entails not only allergic sensitization, but also clinically relevant symptoms triggered by the culprit allergen.

Non-IgE Mediated Food Allergy

Food allergies, defined as an immune response to food proteins, affect as many as 8% of young children and 2% of adults in western countries, and their prevalence appears to be rising like all allergic diseases. In addition to well-recognized urticaria and anaphylaxis triggered by IgE antibody- mediated immune responses, there is an increasing recognition of cell-mediated disorders, such as eosinophilic esophagitis and food protein-induced enterocolitis. Non-IgE-Mediated gastrointestinal food allergies are a heterogeneous group of food allergies in which there is an immune reaction against food but the primary pathogenesis is not a production of IgE and activation of mast cells and basophils. Those diseases tend to affect mainly the gastrointestinal tract and can present as acute (FPIES) or chronic reaction, such as Eosinophilic Esophagitis (EoE), Food Protein-Induced Allergic Proctocolitis (FPIAP). The role of food allergy in Non-EoE gastrointestinal Eosinophilic disorders (Non- EoE EGID) is poorly understood. In some diseases like EoE, T cell seems to play a major role in initiating the immunological reaction against food, however, in FPIES and FPIAP, the mechanism of sensitization is not clear. Diagnosis requires food challenges and/or endoscopies in most of the patients, as there are no validated biomarkers that can be used for monitoring or diagnosis of Non-IgE mediated food allergies. The treatment of Non-IgE food allergy is dependent on diet (FPIES, and EoE) and/or use of drugs (i.e. steroids, PPI) in EoE and Non-EoE EGID. Non-IgE mediated food allergies are being being investigated.

IL-13-induced intestinal secretory epithelial cell antigen passages are required for IgE-mediated food-induced anaphylaxis

BACKGROUND

Food-induced anaphylaxis (FIA) is an IgE-dependent immune response that can affect multiple organs and lead to life-threatening complications. The processes by which food allergens cross the mucosal surface and are delivered to the subepithelial immune compartment to promote the clinical manifestations associated with food-triggered anaphylaxis are largely unexplored.

OBJECTIVE

We sought to define the processes involved in the translocation of food allergens across the mucosal epithelial surface to the subepithelial immune compartment in FIA.

METHODS

Two-photon confocal and immunofluorescence microscopy was used to visualize and trace food allergen passage in a murine model of FIA. A human colon cancer cell line, RNA silencing, and pharmacologic approaches were used to identify the molecular regulation of intestinal epithelial allergen uptake and translocation. Human intestinal organoid transplants were used to demonstrate the conservation of these molecular processes in human tissues.

RESULTS

Food allergens are sampled by using small intestine (SI) epithelial secretory cells (termed secretory antigen passages [SAPs]) that are localized to the SI villous and crypt region. SAPs channel food allergens to lamina propria mucosal mast cells through an IL-13-CD38-cyclic adenosine diphosphate ribose (cADPR)-dependent process. Blockade of IL-13-induced CD38/cADPR-dependent SAP antigen passaging in mice inhibited induction of clinical manifestations of FIA. IL-13-CD38-cADPR-dependent SAP sampling of food allergens was conserved in human intestinal organoids.

CONCLUSION

We identify that SAPs are a mechanism by which food allergens are channeled across the SI epithelium mediated by the IL-13/CD38/cADPR pathway, regulate the onset of FIA reactions, and are conserved in human intestine.

Managing Younger Siblings of Food Allergic Children

Current guidelines state that there is insufficient evidence to recommend testing siblings of food allergic children before introduction of potential allergic foods, but the topic continues to remain controversial. Although the proportion of siblings who are sensitized to a food without clinical reactivity is high in comparison to those with a true food allergy, there is still a known increased risk amongst siblings of children with food allergies that has led to much apprehension about management. The appropriateness of testing and further steps for management of sensitization in the absence of history of clinical reactivity should be discussed with parents.

Applying Discriminant and Cluster Analyses to Separate Allergenic from Non-allergenic Proteins

As a result of increased healthcare requirements and the introduction of genetically modified foods, the problem of allergies is becoming a growing health problem. The concept of allergies has prompted the use of new methods such as genomics and proteomics to uncover the nature of allergies. In the present study, a selection of 1400 food proteins was analysed by PLS-DA (Partial Least Square-based Discriminant Analysis) after suitable transformation of structural parameters into uniform vectors. Then, the resulting strings of different length were converted into vectors with equal length by Auto and Cross-Covariance (ACC) analysis. Hierarchical and non-hierarchical (K-means) Cluster Analysis (CA) was also performed in order to reach a certain level of separation within a small training set of plant proteins (16 allergenic and 16 non-allergenic) using a new three-dimensional descriptor based on surface protein properties in combination with amino acid hydrophobicity scales. The novelty of the approach in protein differentiation into allergenic and non-allergenic classes is described in the article.

The general goal of the present study was to show the effectiveness of a traditional chemometric method for classification (PLS–DA) and the options of Cluster Analysis (CA) to separate by multivariate statistical methods allergenic from non-allergenic proteins.

Intestinal overexpression of IL-18 promotes eosinophils-mediated allergic disorders

Baseline eosinophils reside in the gastrointestinal tract; however, in several allergic disorders, excessive eosinophils accumulate in the blood as well in the tissues. Recently, we showed in vitro that interleukin (IL)-18 matures and transforms IL-5-generated eosinophils into the pathogenic eosinophils that are detected in human allergic diseases. To examine the role of local induction of IL-18 in promoting eosinophil-associated intestinal disorders, we generated enterocyte IL-18-overexpressing mice using the rat intestinal fatty acid-binding promoter (Fabpi) and analysed tissue IL-18 overexpression and eosinophilia by performing real-time polymerase chain reaction, Enzyme-Linked Immunosorbent Assay and anti-major basic protein immunostaining. Herein we show that Fabpi-IL-18 mice display highly induced IL-18 mRNA and protein in the jejunum. IL-18 overexpression in enterocytes promotes marked increases of eosinophils in the blood and jejunum. Our analysis shows IL-18 overexpression in the jejunum induces a specific population of CD101⁺  CD274⁺ tissue eosinophils. Additionally, we observed comparable tissue eosinophilia in IL-13-deficient-Fabpi-IL-18 mice, and reduced numbers of tissue eosinophils in eotaxin-deficient-Fabpi-IL-18 and IL-5-deficient-Fabpi-IL-18 mice compared with Fabpi-IL-18 transgenic mice. Notably, jejunum eosinophilia in IL-5-deficient-Fabpi-IL-18 mice is significantly induced compared with wild-type mice, which indicates the direct role of induced IL-18 in the tissue accumulation of eosinophils and mast cells. Furthermore, we also found that overexpression of IL-18 in the intestine promotes eosinophil-associated peanut-induced allergic responses in mice. Taken together, we provide direct in vivo evidence that induced expression of IL-18 in the enterocytes promotes eotaxin-1, IL-5 and IL-13 independent intestinal eosinophilia, which signifies the clinical relevance of induced IL-18 in eosinophil-associated gastrointestinal disorders (EGIDs) to food allergens.

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.

Component resolved diagnostic study of cow's milk allergy in infants and young children in northern China

BACKGROUND

Increasing dairy consumption in China has been accompanied by rising incidence of milk allergy. Here we analyzed profiles of specific immunoglobulin E (sIgE) against cow's milk proteins, and assessed their value for milk allergy diagnosis among infants and young children from northern China.

METHODS

Sera collected from 48 patients with milk allergy and 27 negative control subjects was analyzed by enzyme-linked immunosorbent assay to measure sIgE to α-lactalbumin (Bos d 4), β-lactoglobulin (Bos d 5), α-casein (Bos d 9), β-casein (Bos d 11), and κ-casein (Bos d 12).

RESULTS

Among milk-allergic individuals, most were sensitized to at least one milk protein; about half were sensitized to Bos d 5, Bos d 9, Bos d 11 and Bos d 12, respectively, while few had positive serum sIgE against Bos d 4. Bos d 12 sIgE had the largest area under curve (AUC) (0.878; 95% CI, 0.800-0.957) and thus showed the best diagnostic performance in discriminating between milk-allergic and non-milk allergic patients, with a sensitivity of 92.6% and specificity of 72.9% using a statistically optimal cut-off value (OD_450nm, 0.191). The combinations of Bos d 5 + Bos d 12 showed an AUC of 0.926, which was larger than for any individual components.

CONCLUSIONS

Our results revealed inter-individual variation in the sensitization to different milk allergen component. Bos d 12 sIgE showed best performance in diagnosing milk allergy. Milk allergy diagnostic accuracy was further improved using combinations of milk allergen components by application of ROC curves based on logistic regression.

Modification of IgE binding to αS1-casein by proteolytic activity of Enterococcus faecium isolated from Iranian camel milk samples

Milk is a perfect source of nutrients for neonates. When breast feeding cannot be done, an infant's alimentation is usually initiated to cow's milk, among the primary foods. It has been reported that about 2.5% of juveniles under the age of 3 years manifest allergic reactions to cow's milk proteins. Among the cow's milk proteins, casein fractions are considered as the strongest allergenic proteins. The proteolytic enzymes of lactic acid bacteria (LAB), during fermentation of dairy products, can break down milk proteins especially caseins and subsequently reduce the immune reactivity of allergenic proteins. In this research, raw bovine and camel milk samples were screened for cocci LAB strains and after isolation, their proteolytic activity against bovine milk caseins were evaluated by SDS-PAGE and RP-HPLC. The potential of cocci LAB strains on α_S1-casein degradation and their potential to break down the principle allergenic epitopes of this protein was detected using indirect competitive ELISA. Molecular identification of the best proteolytic strain was fulfilled by 16S rDNA fragment sequencing with universal primers. The obtained results demonstrated that Enterococcus faecium isolated from raw camel milk samples was the most efficient isolate in hydrolyzing Na-caseinate and α_S1-casein. Hydrolysated α_S1-casein by Enterococcus faecium was also less recognized by IgE of bovine milk allergic patients' sera in comparison with native α_S1-casein. It has been proposed that Enterococcus faecium could be an efficient strain in allergenicity reduction of cow's milk proteins. So it could be an excellent candidate to be potentially used in dairy industries.

Lipopolysaccharide suppresses IgE-mast cell-mediated reactions

BACKGROUND

Clinical and experimental analyses have identified a central role for IgE/FcεRI/mast cells in promoting IgE-mediated anaphylaxis. Recent data from human studies suggest that bacterial infections can alter susceptibility to anaphylaxis.

OBJECTIVE

We examined the effect of LPS exposure on the induction of IgE-mast cell (MC) mediated reactions in mice.

METHODS

C57BL/6 WT, tlr4-/- and IL10-/- mice were exposed to LPS, and serum cytokines (TNF and IL-10) were measured. Mice were subsequently treated with anti-IgE, and the symptoms of passive IgE-mediated anaphylaxis, MC activation, Ca2+ -mobilization and the expression of FcεRI on peritoneal MCs were quantitated.

RESULTS

We show that LPS exposure of C57BL/6 WT mice constraints IgE-MC-mediated reactions. LPS-induced suppression of IgE-MC-mediated responses was TLR-4-dependent and associated with increased systemic IL-10 levels, decreased surface expression of FcεRI on MCs and loss of sensitivity to IgE activation. Notably, LPS-induced desensitization of MCs was short term with MC sensitivity to IgE reconstituted within 48 hours, which was associated with recapitulation of FcεRI expression on the MCs. Mechanistic analyses revealed a requirement for IL-10 in LPS-mediated decrease in MC FcεRI surface expression.

CONCLUSIONS & CLINICAL RELEVANCE

Collectively, these studies suggest that LPS-induced IL-10 promotes the down-regulation of MC surface FcεRI expression and leads to desensitization of mice to IgE-mediated reactions. These studies indicate that targeting of the LPS-TLR-4-IL-10 pathway may be used as a therapeutic approach to prevent adverse IgE-mediated reactions.

Phenotypical characterization of peanut allergic children with differences in cross-allergy to tree nuts and other legumes

BACKGROUND

Peanut allergy in children is often associated with allergies to tree nuts and/or legumes. The aim of this study was to analyze in cluster a cohort of children allergic to peanuts and assessed for cross-reactivity to nuts and legumes and to identify different phenotypes.

METHODS

We included retrospectively 317 children with peanut allergy evaluated at the Allergy Unit of the Saint Vincent Hospital of Lille in the last 12 years. A complete workup for peanut allergy and nuts and legumes was carried out for each patient. A hierarchical agglomerative clustering method was used to search for clusters of individuals in the evaluated cohort.

RESULTS

Cross-allergy to TN and/or other legumes was identified in 137 patients (43.2%), atopic dermatitis being a major risk factor (adjusted OR = 16 [95% CI: 7.4-37]; p < 0.001). Three phenotypes emerged from cluster analysis. Cluster 1 (72 patients) is characterized by high level of rAra h 2, low threshold reactive doses for peanut and high proportion of asthma; Cluster 2 (93 patients) is characterized by high threshold reactive doses for peanut and the lowest proportion of cross-allergy to TN and/or legumes; Cluster 3 (152 patients) has a high risk of cross-allergy to TN and/or legumes and most patients suffer from eczema.

CONCLUSIONS

The three phenotypes highlighted by this study could be useful to identify children with high risk of cross-allergic reaction to TNs and legumes early after PA diagnosis.

Ara h 2 cross-linking catalyzed by MTGase decreases its allergenicity

Ara h 2 cross-linking involving linear allergen epitopes significantly decreases its allergenicity.

Use of Food Allergy Panels by Pediatric Care Providers Compared With Allergists

BACKGROUND AND OBJECTIVE

Immunoglobullin E (IgE)-mediated food allergies affect 5% to 8% of children. Serum IgE levels assist in diagnosing food allergies but have low positive predictive value. This can lead to misinterpretation, overdiagnosis, and unnecessary dietary elimination. Use of IgE food allergen panels has been associated with increased cost and burden. The scale of use of these panels has not been reported in the medical literature.

METHODS

We conducted a retrospective review of a commercial laboratory database associated with a tertiary care pediatric academic medical center for food IgE tests ordered by all provider types during 2013.

RESULTS

A total of 10 794 single-food IgE tests and 3065 allergen panels were ordered. Allergists ordered the majority of single-food IgE tests (58.2%) whereas 78.8% of food allergen panels were ordered by primary care providers (PCPs) (P < .001). Of all IgE tests ordered by PCPs, 45.1% were panels compared with 1.2% of orders placed by allergists (P < .001). PCPs in practice for >15 years ordered a higher number of food allergen panels (P < .05) compared with PCPs with less experience. Compared with allergists, PCPs ordered more tests for unlikely causes of food allergies (P < .001). Total cost of IgE testing and cost per patient were higher for PCPs compared with allergists.

CONCLUSIONS

Review of food allergen IgE testing through a high volume outpatient laboratory revealed PCPs order significantly more food allergen panels, tests for uncommon causes of food allergy, and generate higher cost per patient compared with allergists. These results suggest a need for increased education of PCPs regarding proper use of food IgE tests.

Food Allergy: What We Know Now

Food allergy is an adverse immune reaction that occurs reproducibly on exposure to a given food. Prevalence rates of food allergy continue to increase worldwide, sparking continual research efforts in finding a suitable and safe cure. Food avoidance, the current standard of care, can be difficult to achieve. This review aims to provide a broad overview of immunoglobulin E-mediated food allergy, highlighting its epidemiology, masqueraders, immunopathophysiology, clinical presentation, diagnostic work-up and available preventative and treatment strategies. This review also discusses novel, investigative therapies that offer promising therapeutic options, yet require continued research efforts to determine safety effects. Inducing tolerance, whether by immunotherapy or by the administration of monoclonal antibodies, allows us to move toward a cure for food allergy, which could vastly change this field of allergic diseases in the coming decades.

Pearls and Pitfalls in Diagnosing IgE-Mediated Food Allergy

The term "food allergy" is used by many patients and clinicians to describe a range of symptoms that occur after ingestion of specific foods. However, not all symptoms occurring after food exposure are due to an allergic, or immunologic, response. It is important to properly evaluate and diagnose immunoglobulin E (IgE)-mediated food allergy as this results in reproducible, immediate onset, allergic reactions that can progress toward life-threatening anaphylaxis. Proper diagnosis requires understanding of the common foods that cause these reactions in addition to key historical elements such as symptoms, timing and duration of reaction, and risk factors that may predispose to development of IgE-mediated food allergy. Diagnostic testing for food-specific IgE can greatly aid the diagnosis. However, false-positive test results are very common and can lead to overinterpretation, misdiagnosis, and unnecessary dietary elimination. This review discusses important aspects to consider during evaluation of a patient for suspected IgE-mediated food allergy.

Peanut Allergy Treatment: Past, Present, and Future

Objective:

To review the current and future treatments for peanut allergy.

Data Sources:

Literature review was conducted via MEDLINE (1996–October 2003) using OVID and PubMed. The following terms were used: food allergy, peanut allergy, anti-IgE, antihistamine, anaphylaxis, and epinephrine.

Data Synthesis:

Peanut allergy is an immunoglobulin (Ig) E–mediated type I reaction, which is the leading cause of fatal and near-fatal food allergy. Proper diagnosis and treatment plans for patients with peanut allergy are essential. Many patients who have a known life-threatening allergy are far too often unprepared. New treatments aimed at reduction or prevention of anaphylactic reactions are in development.

Conclusions:

Education on the understanding of how to avoid peanut proteins and how to identify signs and symptoms of food allergy is the number one tool in treatment of peanut allergy. The second tool is an easily accessible physician-ordered treatment plan, which includes signs and symptoms of anaphylaxis, proper medications with dosing and administration instructions, and contact numbers. Medications must be available at all times.

Evaluation of the skin-prick test for predicting the outgrowth of cow's milk allergy

Background:

Although considerable efforts have been made to develop diagnostic tools for predicting the outcome of oral food challenges, tests for predicting the outgrowth of food allergies are lacking.

Objective:

The aim of this study was to assess the diagnostic value of the wheal size and skin index (SI) (the ratio of an allergen-induced wheal to a histamine-induced wheal diameter) of the skin-prick test based on the outcome of a controlled oral provocation test for cow's milk. Moreover, we assessed whether wheal size and/or SI were useful for predicting the outgrowth of cow's milk allergy (CMA).

Methods:

This study included 135 children with suspected CMA. Eighty-one patients were definitely diagnosed by oral provocation tests for cow's milk, and their wheal diameters, SIs, and cow milk's–specific serum immunoglobulin E concentrations were determined.

Results:

The wheal diameters were significantly larger and the SIs significantly higher in children with positive oral provocation test results than in those with negative test results. We found that 50% of the patients were expected to be able to drink cow's milk by age 5 years. In these patients, the wheal diameters were significantly smaller and the SIs significantly lower at the time of CMA outgrowth than at the time of diagnosis, whereas these values were apt to increase in patients who did not outgrow CMA, with no significant difference.

Conclusions:

The skin-prick test can be used to diagnose CMA and predict CMA outgrowth. A wheal diameter of 8 mm or/and an SI of 1.0 is informative, not only in diagnosing CMA but also in predicting a natural CMA outgrowth.

Development of a prediction model of severe reaction in boiled egg challenges

BACKGROUND

We have proposed a new scoring system (Anaphylaxis SCoring Aichi: ASCA) for a quantitative evaluation of the anaphylactic reaction that is observed in an oral food challenge (OFC). Furthermore, the TS/Pro (Total Score of ASCA/cumulative protein dose) can be a marker to represent the overall severity of a food allergy. We aimed to develop a prediction model for a severe allergic reaction that is provoked in a boiled egg white challenge.

METHODS

We used two separate datasets to develop and validate the prediction model, respectively. The development dataset included 198 OFCs, that tested positive. The validation dataset prospectively included 140 consecutive OFCs, irrespective of the result. A 'severe reaction' was defined as a TS/Pro higher than 31 (the median score of the development dataset). A multivariate logistic regression analysis was performed to identify the factors associated with a severe reaction and develop the prediction model.

RESULTS

The following four factors were independently associated with a severe reaction: ovomucoid specific IgE class (OM-sIgE: 0-6), aged 5 years or over, a complete avoidance of egg, and a total IgE < 1000 IU/mL. Based on these factors, we made a simple scoring prediction model. The model showed good discrimination in a receiver operating characteristic analysis; area under the curve (AUC) = 0.84 in development dataset, AUC = 0.85 in validation dataset. The prediction model significantly improved the AUC in both datasets compared to OM-sIgE alone.

CONCLUSIONS

This simple scoring prediction model was useful for avoiding risky OFC.

Relationship between respiratory and food allergy and evaluation of preventive measures

Food allergy and respiratory allergy are two frequently associated diseases and with an increasing prevalence. Several reports show the presence of respiratory symptoms in patients with food allergy, while certain foods may be related to the development or exacerbation of allergic rhinitis and asthma. The present update focuses on this relationship, revealing a pathogenic and clinical association between food and respiratory allergy. This association is even more intense when the food hypersensitivity is persistent or starts in the early years of life. Food allergy usually precedes respiratory allergy and may be a risk factor for allergic rhinitis and asthma, becoming a relevant clinical marker for severe atopic asthma. Furthermore, the presence of co-existing asthma may enhance life-threatening symptoms occurring during a food allergic reaction. Recommendations for dietary restrictions during pregnancy and breastfeeding to prevent the development of respiratory allergy are controversial and not supported by consistent scientific data. Current recommendations from medical societies propose exclusive breastfeeding during the first four months of life, with the introduction of solid food in the fourth to the seventh month period of life. A delayed introduction of solid food after this period may increase the risk of developing subsequent allergic conditions. Further studies are encouraged to avoid unjustified recommendations involving useless dietary restrictions.

Food allergy in children with refractory gastroesophageal reflux disease

BACKGROUND

Gastroesophageal reflux disease (GERD) and food allergy are frequent disorders of childhood. The purpose of this study was to determine the frequency of food allergy in children with refractory GERD.

METHODS

A total of 151 children resistant to pharmacologic GERD treatment underwent skin prick test, specific immunoglobulin E, eosinophil count, atopy patch test (APT), and oral food challenge, and were then divided into three groups according to the results of oral milk challenge and allergy work-up: group A1, positive oral milk challenge and positive IgE-mediated allergy test; group A2, positive milk challenge and negative IgE-mediated allergy test; and group B, negative oral milk challenge and negative allergy tests.

RESULTS

There were 35, 30 and 86 patients in group A1, group A2 and group B, respectively. A total of 28 of 35 patients in group A1 had cow's milk allergy and the other seven patients had egg allergy. APT positivity was more common in group A2. Endoscopic esophagitis was observed in six group A1 patients and in four group A2 patients. Bloody stools, atopic dermatitis and recurrent wheezing episodes were significantly more common in group A1 than in group A2 and group B (P < 0.001, for both).

CONCLUSION

Cow's milk allergy was observed frequently in children resistant to pharmacologic GERD treatment. Combined skin prick and specific IgE tests, APT and oral food challenge is essential for avoidance of unnecessary elimination diet.

Clinical management of food allergy

Food allergies are commonly seen by the practitioner, and managing these patients is often challenging. Recent epidemiologic studies report that as many as 1 in 13 children in the United States may have a food allergy, which makes this an important disease process to appropriately diagnose and manage for primary care physicians and specialists alike. Having a understanding of the basic immunologic processes that underlie varying presentations of food-induced allergic diseases will guide the clinician in the initial workup. This review will cover the basic approach to understanding the immune response of an individual with food allergy after ingestion and will guide the clinician in applying appropriate testing modalities when needed by conducting food challenges if indicated and by educating the patient and his or her guardian to minimize the risk of accidental ingestion.

Quality of Life in Food Allergy Patients and Their Families

Pediatric food allergy is a growing health problem in the United States that has been found to adversely impact the quality of life of both affected children and their caregivers. This article provides a review of how food allergy affects the quality of life of patients and their families within the domains of school, social activities, relationships, and daily life. Efforts to improve food allergy-related quality of life among caregivers are also discussed.