Adverse reactions to foods

Digestion-Resistant Linear Epitopes as Dominant Contributors to Strong Allergenicity of Tropomyosin in Antarctic Krill (Euphausia superba)

Although tropomyosin has been identified as a major allergen in Antarctic krill, the digestive fate of Antarctic krill tropomyosin and its relationship with allergenicity are unknown. In this study, Antarctic krill tropomyosin was administered to BALB/c mice via both gavage and intraperitoneal injection to explore its sensitizing and eliciting capacity, and its digestion products were analyzed for structural changes and digestion-resistant linear epitopes. Mice gavaged with tropomyosin exhibited lower levels of specific IgE and IgG1, mast cell degranulation, vascular permeability, and anaphylaxis symptoms than those in the intraperitoneal injection group. This may be due to the destruction of macromolecular aggregates, loose expansion of the tertiary structure, complete disappearance of α-helix, and significant changes in molecular force upon the digestion of tropomyosin. Nevertheless, the intragastric administration of Antarctic krill tropomyosin still triggered strong allergic reactions, which was attributed to the existence of seven digestion-resistant linear epitopes (Glu26-His44, Thr111-Arg125, Glu157-Glu164, Glu177-Gly186, Val209-Ile225, Arg244-Arg255, and Val261-Ile270).

Eosinophilic gastroenteritis: Pathogenesis, diagnosis, and treatment

ABSTRACT

Eosinophilic gastroenteritis (EGE) is a gastrointestinal disorder of unclear etiology that is characterized by eosinophilic infiltration of the stomach and small intestine, and consists of mucosal, muscular, and serosal subtypes. Eosinophilic infiltration of the gastrointestinal tract is a fundamental histopathological characteristic of EGE and is driven by several T-helper type 2 (Th2)-dependent cytokines and induced by food allergy. Due to the lack of a diagnostic gold standard, EGE has a high rate of delayed diagnosis or misdiagnosis. However, several new diagnostic strategies have been developed, such as novel genetic biomarkers and imaging tests. Although dietary therapy and corticosteroids remain the common choices for EGE treatment, recent decades have seen the emergence of novel treatment alternatives, such as biologics that target particular molecules involved in the pathogenic process. Preliminary investigations and clinical trials have demonstrated the efficacy of biologics and provided additional insights for the era of refractory or corticosteroid-dependent EGE biologics.

Gastrointestinal IgG4 Deposition Is a New Histopathological Feature of Eosinophilic Gastroenteritis

BACKGROUND

The pathogenesis of eosinophilic esophagitis involves immunoglobulin G4 (IgG4) deposition. However, the relationship between IgG4 and eosinophilic gastroenteritis (EGE) is unclear.

AIMS

To investigate gastrointestinal deposition of IgG4 in EGE.

METHODS

Biopsies of the esophagus, stomach, and small intestine were evaluated in patients with and without EGE. Immunohistochemical staining for IgG4 was performed, and the proportions of the stained areas were compared. Sera from patients with EGE were assayed for food-specific IgG4, including egg white, wheat, rice, soy, and cow milk.

RESULTS

Seventeen patients were included in this study (EGE group, n = 10; control group, n = 7). Compared with the control group, the proportion of IgG4-stained area in the EGE group was approximately threefold higher (40.2% [32.3-49.5]) vs. 12.1% [4.0-21.9], p = 0.014) in the esophagus, fivefold higher in the stomach (17.3% [11.1-26.2] vs. 3.7% [1.5-5.2], p = 0.014), and sixfold higher in the small intestine (28.0% [15.0-33.2] vs. 4.5% [2.6-9.8], p = 0.019). There was no significant association between the proportion of IgG4-stained area and the number of infiltrating eosinophils. Serum egg white-specific IgG4 levels were correlated with the proportion of IgG4-stained areas in the small intestine (R = 0.7, p = 0.035).

CONCLUSIONS

IgG4 accumulated within the gastrointestinal mucosa in EGE. The positive correlation between serum egg white-specific IgG4 levels and the proportion of IgG4-stained areas in the small intestine suggests a role for IgG4 in the disease pathophysiology.

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.

Food-induced anaphylaxis in early childhood and factors associated with its severity

Background: Several factors that increase the risk of severe food-induced anaphylaxis have been identified. Objective: We aimed to determine the demographic, etiologic, and clinical features of food-induced anaphylaxis in early childhood and also any other factors associated with severe anaphylaxis. Methods: We carried out a medical chart review of anaphylaxis cases from 16 pediatric allergy and immunology centers in Turkey. Results: The data of 227 patients with 266 food-induced anaphylaxis episodes were included in the study. The median (interquartile range) age of the first anaphylaxis episode was 9 months (6-18 months); 160 of these patients were boys (70.5%). The anaphylaxis episodes were mild in 75 cases (28.2%), moderate in 154 cases (57.9%), and severe in 37 cases (13.9%). The most frequent food allergens involved were cow's milk (47.4%), nuts (16.7%), and hen's egg (15.8%). Epinephrine was administered in only 98 (36.8%) of these anaphylaxis episodes. A logistic regression analysis revealed two statistically significant factors that were independently associated with severe anaphylaxis: the presence of angioedema and hoarseness during the anaphylactic episode. Urticaria was observed less frequently in patients who developed hypotension. In addition, confusion and syncope were associated with 25.9- and 44.6-fold increases, respectively, in the risk of concomitant hypotension. Conclusion: Cow's milk, nuts, and hen's egg caused the majority of mild and moderate-to-severe anaphylaxis episodes. The presence of angioedema and hoarseness in any patient who presents with a history of food-induced anaphylaxis should alert clinicians that the reaction may be severe. In addition, the presence of confusion, syncope, or stridor probably indicates concomitant hypotension.

Genetics of Food Allergy

The risk factors for food allergy (FA) include both genetic variants and environmental factors. Advances using both candidate-gene association studies and genome-wide approaches have led to the identification of FA-associated genes involved in immune responses and skin barrier functions. Epigenetic changes have also been associated with the risk of FA. In this chapter, we outline current understanding of the genetics, epigenetics and the interplay with environmental risk factors associated with FA. Future studies of gene-environment interactions, gene-gene interactions, and multi-omics integration may help shed light on the mechanisms of FA, and lead to improved diagnostic and treatment strategies.

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.

Predictors of a positive oral food challenge to cow's milk in children sensitized to cow's milk

INTRODUCTION AND OBJECTIVES

The diagnosis of IgE-mediated cow's milk allergy (CMA) is often based on clinical history and on specific IgE levels and/or skin-prick tests (SPT), both of which are sensitive but not specific. The gold standard, oral food challenge (OFC), is expensive and time-consuming and involves a risk of severe allergic reactions. This study aimed to determine the value of specific IgEs, ratios of specific IgEs for cow's milk and its components to total IgE, and wheal size on SPT for predicting a positive OFC for CMA.

MATERIAL AND METHODS

We retrospectively studied 72 patients [median age, four years; age range 0.75-15 years] sensitized to cow's milk who underwent OFCs to milk. predictive variables between patients with positive and negative OFCs were compared. Receiver operator characteristic (ROC) curves were uses to assess variables' discriminatory capacity and Youden's index to determine the best cut-offs for predicting CMA.

RESULTS

The OFC was positive in 39 (54%) patients. Wheal size on SPT and all specific IgEs and specific-to-total IgE ratios were significantly different between patients with positive OFCs and those with negative OFCs (p<0.001). The variable with the greatest area under the ROC curve was casein-specific IgE (0.98), followed by β-lactoglobulin-specific IgE (0.923), casein-specific-to-total-IgE ratio (0.919), and α-lactalbumin-specific IgE (0.908). Casein-specific IgE ≥0.95kU/L yielded 88.9% sensitivity and 90.9% specificity.

CONCLUSIONS

In our center, casein-specific IgE >0.95kU/L can obviate an OFC to cow's milk for the diagnosis of CMA in patients sensitized to cow's milk with a compatible history.

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.

Clinical and Laboratory Characteristics of Patients with Food Allergy: Single-Center Experience

Objectives:

This study aimed to examine the clinical and laboratory features of the patients diagnosed with food allergy who applied to the pediatric allergy outpatient clinic.

Methods:

This study was performed between March 2016 and December 2017 as a cross-sectional observational study. The files of 90 patients with food allergy were evaluated retrospectively.

Results:

Ninety patients were included in the study. Sixty three (70%) of the cases were male and 27 (30%) were female. The median age of the patients was 12 months (range 3-156), and the age at onset of symptoms was 4 months (1-156). At the time of the diagnosis, the total number of eosinophils was 410/mm³ (0-4600), and the total IgE value was 83.1 IU/ml (3.17-2500). When the cases were divided into two groups according to their gender, no significant difference was found between the groups regarding the median age, onset age of the symptoms, total IgE, eosinophil and specific IgE levels. Fifty (55.6%) cases had atopic dermatitis, 31 (34.4%) had urticaria, 6 (6.7%) had proctocolitis, 2 (2.2%) had angioedema and 1 (1.1%) had anaphylaxis. Thirty-four (37.8%) of the cases had IgE-mediated, six (6.7%) cases had non-IgE mediated, and 50 (55.5%) cases had mixed type food allergy. The most common food allergens were egg 29 (32.2%), cow’s milk and egg 27 (30%) and cow’s milk 22 (24.4%). In the skin prick test, sensitivity was found in 52 (57.7%) patients. The most common sensitization was against egg (22.2%). Specific IgE values were found as F1: 0.87 kU/L (0.10-100), F2: 0.30 kU/L (0.10-96.90) and F5: 0.48 kU/L (0.10-53).

Conclusion:

Egg and cow’s milk allergy were the most common food allergens in our study. However; more than half of the patients were diagnosed with atopic dermatitis. Evaluation of the patients with atopic dermatitis in terms of food allergy may be appropriate.

Hypoallergenic diet may control refractory epilepsy in allergic children: A quasi experimental study

Recent data has suggested a definitive role for inflammatory processes in the pathophysiology of epilepsy. In this study we hypothesized that food allergies, as chronic inflammatory processes, underlie the pathophysiology of refractory idiopathic epilepsy and investigated whether food elimination diets may assist in managing refractory epilepsy. The study was conducted on 34 patients up to 16 years of age with refractory convulsions who attended the Allergy Outpatient Clinic, Mofid Children Hospital between 2015 and 2016 with youngest and oldest participants at ages of 3 months and 16 years old, respectively. The participants were categorized into three groups according to the results of skin prick test and serum specific IgE measurements. Elimination diets were instituted for the patients with non IgE-mediated and mixed food allergies. The study was conducted for a period of 12 weeks. The participants were assessed for at least 50% reduction in number of seizures following the intervention. There was a significant reduction in number of seizures (p < 0.001) following the intervention. Seventeen patients (50%) did not experience any seizures after 8 weeks of treatment and 12 patients (35%) had a significant (51–99%) decrease in the number of their seizures. Five patients did not show any changes in their daily seizure frequency. The obtained data suggest that food allergy may play a role in triggering refractory epilepsies and their adequate response to treatment. A trial of elimination diet showed more than 50% seizure reduction in more than 85% of the children studied. However, we believe these results are preliminary and they motivate a fully controlled study in the future.

Experimental Models for Studying Food Allergy

Immunoglobulin E-mediated food allergy is rapidly developing into a global health problem. Publicly available therapeutic intervention strategies are currently restricted to allergen avoidance and emergency treatments. To gain a better understanding of the disease pathophysiology so that new therapies can be developed, major research efforts have been put into studying food allergy in mice. Animal models should reflect the human pathology as closely as possible to allow for a rapid translation of basic science observations to the bedside. In this regard, experimental models of food allergy provide significant challenges for research because of discrepancies between the presentation of disease in humans and mice. The goal of this review is to give a summary of commonly used murine disease models and to discuss how they relate to the human condition. We will focus on epicutaneous sensitization models, on mouse strains that sensitize spontaneously to food as seen in humans, and on models in humanized animals. In summary, expanding the research toolbox of experimental food allergy provides an important step toward closing gaps in our understanding of the derailing immune mechanism that underlies the human disease. The availability of additional experimental models will provide exciting opportunities to discover new intervention points for the treatment of food allergies. (Cell Mol Gastroenterol Hepatol 2018;x:x).

IL-33 promotes gastrointestinal allergy in a TSLP-independent manner

Atopic dermatitis (AD) often precedes asthma and food allergy, indicating that epicutaneous sensitization to allergens may be important in the induction of allergic responses at other barrier surfaces. Thymic stromal lymphopoietin (TSLP) and interleukin (IL)-33 are two cytokines that may drive type 2 responses in the skin; both are potential targets in the treatment of allergic diseases. We tested the functional role of IL-33 and the interplay between IL-33 and TSLP in mouse models of atopic march and gastrointestinal (GI) allergy. IL-33-driven allergic disease occurred in a TSLP-independent manner. In contrast, mice lacking IL-33 signaling were protected from onset of allergic diarrhea in TSLP-driven disease. Epithelial-derived IL-33 was important in this model, as specific loss of IL-33 expression in the epithelium attenuated cutaneous inflammation. Notably, the development of diarrhea following sensitization with TLSP plus antigen was ameliorated even when IL-33 was blocked after sensitization. Thus, IL-33 has an important role during early cutaneous inflammation and during challenge. These data reveal critical roles for IL-33 in the "atopic march" that leads from AD to GI allergy.

Age-Based Causes and Clinical Characteristics of Immediate-Type Food Allergy in Korean Children

PURPOSE

Age-based causes and clinical characteristics of immediate-type food allergy (FA) have not been sufficiently studied. Therefore, we investigated age-dependent clinical profiles of FA in Korean children through an extensive multicenter investigation.

METHODS

Using a case report form developed by the authors, a retrospective medical record review was performed of patients (0-18 years old) diagnosed with immediate-type FA between September 2014 and August 2015 in 14 tertiary hospitals in Korea.

RESULTS

A total of 1,353 children and adolescents, 93% younger than 7 years, were enrolled in the present study, and 1,661 cases of immediate-type FA were recorded in these patients. The 7 major causative foods were cow's milk (28.1%), hen's eggs (27.6%), wheat (7.9%), walnuts (7.3%), peanuts (5.3%), buckwheat (1.9%), and shrimps (1.9%). Categorizing the patients into 4 age groups revealed that the most common causative food was different for each age group: cow's milk (<2 years), walnuts (2-6 years), walnuts (7-12 years), and buckwheat (13-18 years). The onset time of symptoms was less than 10 minutes in 49%, between 10 and 30 minutes in 17%, and between 30 minutes and 2 hours in 34% of cases. Food-induced anaphylaxis was reported in 506 (30.5%) out of 1,661 cases, and the 7 major causes of food-induced anaphylaxis was cow's milk (27.5%), hen's eggs (21.9%), wheat (11.3%), walnuts (10.5%), peanuts (5.9%), buckwheat (4.2%), and pine nuts (3.0%). The proportion of anaphylaxis was highest in the patients allergic to buckwheat (67.7%), followed by those allergic to pine nuts (57.7%), walnuts (43.8%), wheat (43.5%), and peanuts (34.1%).

CONCLUSIONS

The 5 major causative foods of immediate-type FA in Korean children were cow's milk, hen's eggs, wheat, walnuts, and peanuts. The distribution of causative foods was considerably distinctive according to different age groups. Anaphylaxis was reported in 30.5% of immediate-type FA cases.

Measurement of Electrical Skin Impedance of Dermal-Visceral Zones as a Diagnostic Tool for Disorders of the Immune System

Among complementary medicine approaches, diagnostic screening tools based on neuroreflexology have been recently developed. Such techniques are based on the rationale that measurement of electrical impedance of specific dermal zones might reflect the occurrence of pathological states in the corresponding internal organs or systems. Our objective was to evaluate the reliability of a neuroreflexology-based diagnostic test in diagnosing immune-mediated diseases in a blinded single centre study. Seventy-eight patients with immune-mediated diseases (38 patients with autoimmune diseases (AD), and 40 allergic patients) were included in the study. Thirty age and sex matched healthy subjects were also evaluated as a control group. All the patients and subjects underwent conventional medical history and physical examination. We evaluated a device manufactured by Medex Screen Ltd (Arad, Israel). The Medex Test analysis was carried out by a second physician who was blinded to the previous diagnosis. A high correlation between the formal clinical diagnosis and the results of the measurement of electrical skin impedance was reported, with a specificity of 93.3% and a sensitivity of 81.2%. Both sensitivity and specificity dropped when analysing the autoimmune and the allergic group separately, but remained significant for the autoimmune diseases. Degree of activity of the allergic disorders, or specific treatment, did not affect the diagnostic properties of the described device. The Medex Test neurophysiology based technique has the potential to serve as a diagnostic tool for immune based pathologies. Future studies will define this tool place in routine evaluation and potential screening ability.

Eosinophilic esophagitis is characterized by a non-IgE-mediated food hypersensitivity

Eosinophilic esophagitis (EoE) is a chronic disease characterized clinically by symptoms of esophageal dysfunction and histologically by eosinophil-predominant inflammation. EoE is frequently associated with concomitant atopic diseases and immunoglobulin E (IgE) sensitization to food allergens in children as well as to aeroallergens and cross-reactive plant allergen components in adults. Patients with EoE respond well to elemental and empirical food elimination diets. Recent research has, however, indicated that the pathogenesis of EoE is distinct from IgE-mediated food allergy. In this review, we discuss the individual roles of epithelial barrier defects, dysregulated innate and adaptive immune responses, and of microbiota in the pathogenesis of EoE. Although food has been recognized as a trigger factor of EoE, the mechanism by which it initiates or facilitates eosinophilic inflammation appears to be largely independent of IgE and needs to be further investigated. Understanding the pathogenic role of food in EoE is a prerequisite for the development of specific diagnostic tools and targeted therapeutic procedures.

Food-induced immunoglobulin E-mediated allergic rhinitis

Food allergies are estimated about 1–2% in adults and 8% in children younger than 6 years. Allergic rhinitis is a common disease with a prevalence of 40% among different societies. Although, some foods play a role on exacerbation of allergic rhinitis symptoms, but still there are controversies about the role of diet on incidence or worsening the symptoms. The ongoing research demonstrates a possible relationship between certain foods and their induction of allergic reactions by modulating immunoglobulin E. A total of 100 patients (including both children and adults), between the ages 10 to 60 years, diagnosed with allergic rhinitis were selected for the study. Pregnant females and treated patients with antihistamine were excluded from the study. In vitro serum immunoglobulin E (IgE) levels mediated by a combination of food and inhalant allergens were detected by RIDA^® Allergy Screen in blood samples. Data were presented as mean, standard deviation and standard error. A statistical analysis was performed by one-way analysis of variance (ANOVA). A p value < 0.05 was considered statistically significant. We reported that 63% of patients with allergic rhinitis were sensitized to common food allergens whereas the rest 37% of patients were not sensitive to any of the food allergens. Similarly, a correlation between the age groups of patients with allergic rhinitis and food allergy were also accomplished. We found the highest response rate for allergic rhinitis and food allergy (53.2%) for the people between aged between 21 years and 40 years. We also demonstrated that females are more prone to mediate allergic rhinitis as induced by food allergies as compare to males (i.e., 66.2% vs. 33.3%). Food allergy is estimated to be 4.5% in adolescents and adults with asthma, rhinitis or both. Rice, citrus fruits, black grams and banana are identified as major allergens for inducing allergic-rhinitis symptoms.

Establishing a cut-off for the serum levels of specific IgE to milk and its components for cow's milk allergy: results from a specific population

BACKGROUND

Cow's milk allergy diagnosis many times requires double-blind placebo-controlled food challenge (DBPCFC), which presents high accuracy but involves risks, specifically in infants and anaphylactic patients. The identification of the cut-off values for specific IgE to milk or its components would contribute to cow's milk allergy (CMA) diagnosis. The aim of this study was to compare discriminating concentration of a cow's milk specific IgE and its fractions (α-lactoalbumin, β-lactoglobulin, casein) in children for the CMA diagnosis.

METHODS

this study included 123 patients (M:F=1.3:1) median age at diagnosis=1.91 years, (3.5m to 13.21y) with CMA diagnosis via DBPCFC (n=26), proven anaphylaxis due to cow's milk (n=46) or a suggestive clinical history associated with a positive skin prick test (n=51) and open oral food challenge. The control group included 61 patients (1 male:1.1 female) ages ranging from 0.66 to 16.7 years (median=6.83 years). Receiver operator characteristics (ROC) curves were constructed to determine the best cut-offs that guarantees high specificity (>95%) for cow's milk and its components.

RESULTS

considering 98% specificity, cut-off points were: 3.06 kU/L for cow's milk, 2.06 kU/L for α-lactalbumin, 1.85 kU/L for β-lactoglobulin and 1.47kU/L for casein. The best ROC curve (area under the curve=0.929) was obtained evaluating cow's milk.

CONCLUSION

this study showed that the cut-off point detected for whole cow's milk revealed a better discriminatory capacity for CMA diagnosis without the necessity of the milk components testing.

EAACI food allergy and anaphylaxis guidelines: managing patients with food allergy in the community

The European Academy of Allergy and Clinical Immunology (EAACI) Food Allergy and Anaphylaxis Guidelines, managing patients with food allergy (FA) in the community, intend to provide guidance to reduce the risk of accidental allergic reactions to foods in the community. This document is intended to meet the needs of early-childhood and school settings as well as providers of non-prepackaged food (e.g., restaurants, bakeries, takeaway, deli counters, and fast-food outlets) and targets the audience of individuals with FA, their families, patient organizations, the general public, policymakers, and allergists. Food allergy is the most common trigger of anaphylaxis in the community. Providing children and caregivers with comprehensive information on food allergen avoidance and prompt recognition and management of allergic reactions are of the utmost importance. Provision of adrenaline auto-injector devices and education on how and when to use these are essential components of a comprehensive management plan. Managing patients at risk of anaphylaxis raises many challenges, which are specific to the community. This includes the need to interact with third parties providing food (e.g., school teachers and restaurant staff) to avoid accidental exposure and to help individuals with FA to make safe and appropriate food choices. Education of individuals at risk and their families, their peers, school nurses and teachers as well as restaurant and other food retail staff can reduce the risk of severe/fatal reactions. Increased awareness among policymakers may improve decision-making on legislation at local and national level.

Probiotics and food allergy

The exact prevalence of food allergy in the general population is unknown, but almost 12% of pediatric population refers a suspicion of food allergy. IgE mediated reactions to food are actually the best-characterized types of allergy, and they might be particularly harmful especially in children. According to the "hygiene hypothesis" low or no exposure to exogenous antigens in early life may increase the risk of allergic diseases by both delaying the development of the immune tolerance and limiting the Th2/Th1 switch. The critical role of intestinal microbiota in the development of immune tolerance improved recently the interest on probiotics, prebiotics, antioxidants, polyunsaturated fatty acid, folate and vitamins, which seem to have positive effects on the immune functions.Probiotics consist in bacteria or yeast, able to re-colonize and restore microflora symbiosis in intestinal tract. One of the most important characteristics of probiotics is their safety for human health. Thanks to their ability to adhere to intestinal epithelial cells and to modulate and stabilize the composition of gut microflora, probiotics bacteria may play an important role in the regulation of intestinal and systemic immunity. They actually seem capable of restoring the intestinal microbic equilibrium and modulating the activation of immune cells.Several studies have been recently conducted on the role of probiotics in preventing and/or treating allergic disorders, but the results are often quite contradictory, probably because of the heterogeneity of strains, the duration of therapy and the doses administered to patients. Therefore, new studies are needed in order to clarify the functions and the utility of probiotics in food allergies and ion other types of allergic disorders.

Interleukin 10 (IL10) and transforming growth factor β1 (TGFβ1) gene polymorphisms in persistent IgE-mediated cow's milk allergy

OBJECTIVES

The aim of this cross-sectional study was to evaluate whether interleukin 10 (IL10) and transforming growth factor β1 (TGFβ1) gene polymorphisms were associated with persistent IgE-mediated cow's milk allergy in 50 Brazilian children. The diagnostic criteria were anaphylaxis triggered by cow's milk or a positive double-blind, placebo-controlled food challenge. Tolerance was defined as the absence of a clinical response to a double-blind, placebo-controlled food challenge or cow's milk exposure.

METHOD

The genomic DNA of the 50 patients and 224 healthy controls (HCs) was used to investigate five IL10 gene polymorphisms (-3575A/T, -2849A/G, -2763A/C, -1082G/A, -592C/A) and one TGFβ1 polymorphism (-509C/T).

RESULTS

Among the five IL10 polymorphisms analyzed, homozygosis for the G allele at the -1082 position was significantly higher in the patients compared with the healthy controls (p=0.027) and in the persistent cow's milk allergy group compared with the healthy controls (p=0.001).

CONCLUSIONS

Homozygosis for the G allele at the IL10 -1082G/A polymorphism is associated with the persistent form of cow's milk allergy.

The management of food allergy in Indonesia

Prevalence of allergic diseases is increasing worldwide, including food allergy. It is different between countries because food allergy can vary by culture and population. Prevalence of food allergy in Indonesia is unknown; therefore it is not known yet the burden and impact of food allergy in our population. However, we already start to formulate guidelines for diagnosis and management of food allergy, especially cow's milk allergy.

A prediction rule for food challenge outcome in children

BACKGROUND

In children with food-related symptoms, a food challenge is considered as the gold standard to diagnose allergy. If food allergy could be predicted by patient history and/or diagnostic tests, the number of time-consuming and sometimes risky food challenges could be decreased. We aimed to determine questionnaire and test-based characteristics, to predict the food challenge outcome (FCO) in children referred to a tertiary centre for the evaluation of food-related symptoms.

METHODS

Pre-challenge standardized questionnaires, skin prick tests (SPT), and specific IgE levels (sIgE) were obtained in patients that underwent a food challenge in our hospital in 2009. Characteristics of patients with positive and negative FCO were compared, and uni- and multivariate associations between predictors and FCO were calculated. Based on the multivariate model, a risk score was developed to predict the FCO.

RESULTS

One hundred and twenty-nine challenges were analyzed, 41.9% had a positive outcome. Median age of both groups was 4.9 yrs (range 2.8-8.3). Patients with a positive FCO reacted faster with symptoms after allergen ingestion and had higher sIgE levels compared to children with negative FCO. A clinical risk score was developed based on the index food, 'time between allergen ingestion and complaints' and sIgE levels (range 0-10). The prognostic capacity of this model (AUC) was excellent (0.90). The very high- and low-risk groups (24% of patients) are both predicted excellent without misclassification.

CONCLUSION

Positive FCO can be predicted by the index food, time between allergen ingestion and development of symptoms, and the sIgE level.

Food-induced anaphylaxis

Food-induced anaphylaxis (FIA) is a serious allergic reaction that may cause death rapidly in otherwise healthy individuals. There is no universal agreement on its definition or criteria for diagnosis. Hospital admissions for FIA have more than doubled in the last decade. Food is one of the most common causes of anaphylaxis, with most surveys indicating that food-induced reactions account for 30% to 50% of cases. The most commonly implicated foods are peanut, tree nuts, milk, eggs, sesame seeds, fish, and shellfish. The only life-saving treatment for anaphylaxis is allergen avoidance, and epinephrine injection if an anaphylactic event occurs.

Kidney bean: a major sensitizer among legumes in asthma and rhinitis patients from India

Background

The prevalence of IgE mediated food allergies has increased over the last two decades. Food allergy has been reported to be fatal in highly sensitive individuals. Legumes are important food allergens but their prevalence may vary among different populations. The present study identifies sensitization to common legumes among Indian population, characterizes allergens of kidney bean and establishes its cross reactivity with other legumes.

Methodology

Patients (n = 355) with history of legume allergy were skin prick tested (SPT) with 10 legumes. Specific IgE (sIgE) and total IgE were estimated in sera by enzyme-linked immunosorbent assay. Characterization of kidney bean allergens and their cross reactivity was investigated by immunobiochemical methods. Identification of major allergens of kidney bean was carried out by mass spectrometry.

Principal Findings

Kidney bean exhibited sensitization in 78 (22.0%) patients followed by chickpea 65 (18.0%) and peanut 53 (15%). SPT positive patients depicted significantly elevated sIgE levels against different legumes (r = 0.85, p<0.0001). Sera from 30 kidney bean sensitive individuals exhibited basophil histamine release (16–54%) which significantly correlated with their SPT (r = 0.83, p<0.0001) and sIgE (r = 0.99, p<0.0001). Kidney bean showed eight major allergens of 58, 50, 45, 42, 40, 37, 34 and 18 kDa on immunoblot and required 67.3±2.51 ng of homologous protein for 50% IgE inhibition. Inhibition assays revealed extensive cross reactivity among kidney bean, peanut, black gram and pigeon pea. nLC-MS/MS analysis identified four allergens of kidney bean showing significant matches with known proteins namely lectin (phytohemagglutinin), phaseolin, alpha-amylase inhibitor precursor and group 3 late embryogenesis abundant protein.

Conclusion/Significance

Among legumes, kidney bean followed by chick pea and peanut are the major allergic triggers in asthma and rhinitis patients in India. Kidney bean showed eight major allergens and cross reacted with other legumes. A combination of SPT, sIgE and histamine release assay is helpful in allergy diagnosis.

Thymic stromal lymphopoietin is required for gastrointestinal allergy but not oral tolerance

BACKGROUND & AIMS

Thymic stromal lymphopoietin (TSLP) is a cytokine produced by epithelial cells that acts on dendritic cells, mast cells, T cells, and B cells. TSLP is involved in the pathogenesis of allergic inflammation in the lung and skin, but data indicate a regulatory role in the gastrointestinal tract. We tested the functional role of TSLP in mouse models of gastrointestinal allergy and tolerance.

METHODS

TSLP Receptor (TSLPR)(+/+) and TSLPR(-/-) mice were sensitized and challenged with ovalbumin; models of allergic diarrhea or systemic anaphylaxis were studied. To induce oral tolerance, mice were fed with low-dose ovalbumin before they were immunized with it. Tolerance was measured from inhibition of ear swelling in a delayed-type hypersensitivity reaction.

RESULTS

TSLPR(-/-) mice were protected from the onset of allergic diarrhea; they did not develop mastocytosis in the jejunum and had reduced ovalbumin-immunoglobulin E in their serum, compared with TSLPR(+/+) mice. TSLPR(-/-) mice also lost T helper cell (Th) 2-mediated inflammation in the jejunum. In contrast, sensitization and oral tolerance were not impaired in TSLPR(-/-) mice. Transfer of wild-type, Th2-primed cells to TSLPR(-/-) mice completely restored the development of allergic diarrhea. Antigen presentation assays showed that TSLPR on T cells, but not dendritic cells, was required to mediate the Th2 response.

CONCLUSIONS

TSLP is required for allergic inflammation but not primary sensitization or tolerance to food proteins in the gastrointestinal tract; it amplifies Th2 responses directly from CD4(+) T cells.

Allergic rhinitis caused by food allergies

Food allergies occur in 1-2% of adults and in 8% of children under 6 years of age. Food-induced allergies are immunological reactions that cause a variety of symptoms affecting the skin, gastrointestinal tract, and respiratory tract. The reactions are mediated by both IgE- and non-IgE-dependent (cellular) mechanisms. Isolated food-induced allergic rhinitis is not common as it frequently occurs together with other food allergy symptoms such as asthma, eczema, oral allergic manifestations, urticaria, and gastrointestinal symptoms. The present paper provides an overview of food allergies and food-induced allergic rhinitis.

The role of immunoglobulin E-binding epitopes in the characterization of food allergy

PURPOSE OF REVIEW

Allergen-specific immunoglobulin E (IgE) antibodies play a central role in food allergic reactions. IgE epitope mapping of food allergens may provide information regarding patient's clinical history and contribute to food allergy diagnosis/prognosis. The goal of this article is to review recent developments in the methods for IgE epitope mapping and the role of IgE-binding epitopes in the characterization of food allergy.

RECENT FINDINGS

Recent studies have suggested a potential role for sequential IgE-binding epitopes as biomarkers for characterizing various phenotypes of food allergy. Studies of allergens in milk, peanut, egg and wheat have shown a correlation between IgE sequential epitope diversity and patients' allergy severity or persistence. Several informative epitopes in milk allergens have been identified as candidate biomarkers to predict the development of tolerance to milk. However, limitations with current methods of IgE-binding epitope identification need to be addressed before they can be applied in the diagnosis/prognosis of food allergy.

SUMMARY

IgE epitope mapping has the potential to become an additional tool for the diagnosis/prognosis of food allergy and lead to a better understanding of the pathogenesis and tolerance induction of food allergy.

Evaluation, diagnosis, and treatment of gastrointestinal disorders in individuals with ASDs: a consensus report

Autism spectrum disorders (ASDs) are common and clinically heterogeneous neurodevelopmental disorders. Gastrointestinal disorders and associated symptoms are commonly reported in individuals with ASDs, but key issues such as the prevalence and best treatment of these conditions are incompletely understood. A central difficulty in recognizing and characterizing gastrointestinal dysfunction with ASDs is the communication difficulties experienced by many affected individuals. A multidisciplinary panel reviewed the medical literature with the aim of generating evidence-based recommendations for diagnostic evaluation and management of gastrointestinal problems in this patient population. The panel concluded that evidence-based recommendations are not yet available. The consensus expert opinion of the panel was that individuals with ASDs deserve the same thoroughness and standard of care in the diagnostic workup and treatment of gastrointestinal concerns as should occur for patients without ASDs. Care providers should be aware that problem behavior in patients with ASDs may be the primary or sole symptom of the underlying medical condition, including some gastrointestinal disorders. For these patients, integration of behavioral and medical care may be most beneficial. Priorities for future research are identified to advance our understanding and management of gastrointestinal disorders in persons with ASDs.

The role of allergy evaluation in adults with eosinophilic esophagitis

BACKGROUND

Allergy evaluation and skin prick testing for foods are recommended in all patients with eosinophilic esophagitis. However, the yield of allergy evaluation in adult eosinophilic esophagitis is not known.

GOALS

To determine the yield of allergy evaluation in adults with eosinophilic esophagitis.

STUDY

All adult patients in the Cleveland Clinic eosinophilic esophagitis registry between January 2006 and April 2008 were identified. Diagnosis was based on clinical presentation and endoscopy with biopsies showing > or = 15 eosinophils/hpf. From this group, all patients referred for allergy evaluation were identified. Allergy evaluation consisted of skin testing to foods in all patients. Selected patients underwent skin testing to inhalants based on the presence of concomitant allergic rhinitis and/or asthma. Immediate hypersensitivity skin testing was performed and scored by standard methodology. Patients were referred on an ad hoc basis by the gastroenterologist and not based on a priori identification of an allergic diathesis.

RESULTS

Twenty-six out of 68 patients (38%) completed allergy evaluation. Thirteen out of 26 patients (50%) demonstrated a positive skin test to > or = 1 food allergen. Of the 15 patients who underwent skin testing for inhalants, 14 (93%) had a positive skin test to 1 or more inhalants. In total 21/26 patients (81%) had > or = 1 allergen identified, 16/26 (62%) had > or = 5 allergens identified, and 4/26 (15%) had > or = 10 allergens identified (range: 0 to 20 allergens identified). Peanut, egg white, soybean, cow's milk, and tree nuts were the most common food allergens identified.

CONCLUSIONS

Allergy evaluation has a high yield in adult eosinophilic esophagitis as 81% of referred patients had one or more allergens identified and 50% had one or more skin tests positive to foods. Allergy evaluation should be considered in adult patients with eosinophilic esophagitis.

Food allergy: review, classification and diagnosis

Food allergies, defined as an immune response to food proteins, affect as many as 8% of young children and 2% of adults in westernized 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. New knowledge is being developed on the pathogenesis of both IgE and non-IgE mediated disease. Currently, management of food allergies consists of educating the patient to avoid ingesting the responsible allergen and initiating therapy if ingestion occurs. However, novel strategies are being studied, including sublingual/oral immunotherapy and others with a hope for future.

The Key Events Dose-Response Framework: a foundation for examining variability in elicitation thresholds for food allergens

Food allergies are caused by immunological reactions in individuals sensitized to normal protein components of foods. For any given sensitized individual, the severity of a reaction is generally assumed to be proportional to the dose of allergenic protein. There is substantial clinical evidence that "threshold" doses exist for the elicitation of an allergic reaction; however, the threshold (i.e., lowest dose that elicits a reaction) varies substantially across the sensitized population. Current approaches to protecting sensitized individuals from exposure to food allergens are highly qualitative (i.e., they rely on food avoidance). The Key Events Dose-Response Framework is an analytical approach for refining understanding of the biological basis of the dose-response. Application of this approach to food allergy provides a foundation for a more rigorous quantitative understanding of variability in allergic response. This study reviews the allergic disease process and the current approaches to identifying thresholds for food allergens. The pathway of key biological events occurring between food intake and allergic response is considered, along with factors that may determine the nature and severity of response to food allergens. Data needs, as well as implications for identifying thresholds, and for characterizing variability in thresholds, are also discussed.

Manifestations of food allergy in infants and children

Most adverse reactions to foods are the result of intolerances rather than food allergy. It is important to identify children with potential food allergy as life-threatening, and life-ending reactions can occur. A clear understanding of the manifestations of food allergy caused by both IgE- and non-IgE-related mechanisms will help the practitioner to identify children who likely have food allergy so that additional diagnostic evaluation can be performed and appropriate avoidance can be instituted.

Approach to patients with symptoms of food allergy

"Allergy" is a term often used by patients to describe symptoms that arise after eating. The term "adverse reaction to food" is preferred unless the event has an immunologic basis. True food allergy, primarily mediated by immunoglobulin (Ig)E antibodies to food proteins, is present in 3% to 4% of US adults. Symptoms range from mild mouth itching ("oral allergy syndrome") to anaphylaxis. The diagnosis is established by history and appropriately performed skin testing or in vitro assays for specific IgE antibodies to the suspected food. Because food-allergic reactions can be fatal, it is important to identify and avoid the causative food. Food-allergic reactions are treated by prompt use of intramuscular epinephrine. Patients may be referred to an allergy/immunology specialist when the diagnosis is uncertain or if avoidance measures are not successful. Investigational therapies may ultimately be preventative or curative.

O conhecimento de pediatras sobre alergia alimentar: estudo piloto

OBJETIVO: Avaliar o conhecimento de pediatras sobre alergia alimentar. MÉTODOS: Dados obtidos de questionário padronizado, postado e respondido por pediatras filiados à Sociedade Brasileira de Pediatria (SBP). Digitação dos dados em planilha Excel e análise de freqüência de respostas afirmativas em porcentagem. RESULTADOS: Foram analisados 895 questionários preenchidos por pediatras de todo o país, com predomínio da região Sudeste (61,6%). Segundo os pediatras entrevistados, as manifestações diagnósticas de alergia alimentar são: respiratórias, cutâneas e sistêmicas, em iguais proporções. Ainda segundo estes pediatras, leite de vaca (98,9%), clara de ovo (58,7%) e amendoim (50,9%) são os principais alimentos associados a essas manifestações. Embora 74,8% dos respondedores tivessem identificados os corantes e aditivos alimentares como responsáveis pela alergia alimentar, apenas 19,4% conheciam o código de identificação da tartrazina. CONCLUSÕES: Os dados apresentados reforçam a necessidade de ampliação dos conhecimentos dos profissionais de saúde sobre o diagnóstico e tratamento da alergia alimentar, com o objetivo de garantir o uso de critérios diagnósticos e terapêuticos mais adequados.

Abordagem laboratorial no diagnóstico da alergia alimentar

OBJETIVO: Revisar os exames laboratoriais disponíveis utilizados no diagnóstico da alergia alimentar mediada ou não por IgE. FONTES DE DADOS: Artigos publicados em base de dados PubMed e Embase (língua inglesa e portuguesa) nos últimos dez anos. As palavras-chave utilizadas como fonte de busca foram "alergia alimentar", "diagnóstico" e "laboratório", isolados e/ou associados. SÍNTESE DOS DADOS: A abordagem diagnóstica das reações alérgicas a alimentos inclui história clínica completa, estudos laboratoriais, dietas de eliminação e desencadeamentos cegos com alimentos. Recentemente, a medida quantitativa de anticorpos IgE específicos a alimentos tem mostrado ser mais preditiva de alergia alimentar sintomática mediada por IgE. Níveis séricos de IgE específica a alimento que excedam os valores diagnósticos indicam que o paciente tem chance maior que 95% de apresentar uma reação alérgica se ingerir o alimento em questão. Estes "valores de decisão" foram definidos para alguns alimentos e resultados inconsistentes são obtidos ao se estudar diferentes populações. Os desencadeamentos com alimento, especialmente o duplo-cego controlado por placebo (DADCCP), representa a maneira mais confiável de estabelecer ou descartar o diagnóstico de hipersensibilidade alimentar. CONCLUSÕES: Número crescente de aquisições tem melhorado o valor preditivo de alguns testes laboratoriais empregados no diagnóstico de alergias alimentares. Entretanto, até hoje, não há teste in vitro ou in vivo que mostre correlação completa com a clínica da alergia alimentar. O DADCCP continua sendo o padrão-ouro no diagnóstico definitivo de alergia alimentar específica. São necessárias, urgentemente, novas abordagens diagnósticas válidadas em pacientes com alergia alimentar confirmada por DADCCP positivo.

Food allergy and anaphylaxis

Food allergy is a common cause of anaphylaxis, and its incidence is rising. The development of allergy is multifactorial, and the mechanisms of tolerance are complex. The natural history of food allergy varies by causative food; some allergies are mostly outgrown, while others are usually life-long. Anaphylaxis caused by food allergy may differ clinically from other causes of anaphylaxis. Death is usually caused by respiratory failure, and patients who have asthma are at greatest risk for severe reactions. At this time, avoiding allergenic triggers, and when that fails, timely administration of epinephrine, are the main approaches to food allergy. Although several experimental medications promise to dramatically change the field of food allergy, none of these treatments are currently available outside of research settings.

Consumer attitudes and risks associated with packaged foods having advisory labeling regarding the presence of peanuts

BACKGROUND

Foods with advisory labeling (eg, "may contain") are increasingly prevalent. Consumers with food allergies might ignore advisory labeling advice.

OBJECTIVE

We sought to determine whether consumers with food allergy heeded advisory labels and whether products with advisory labels contained detectable peanut allergen.

METHODS

Surveys (n = 625 in 2003 and n = 645 in 2006) were conducted at Food Allergy & Anaphylaxis Network patient conferences. Food products bearing advisory statements regarding peanuts were analyzed for the presence of peanut.

RESULTS

Consumers were less likely to heed advisory labeling in 2006 (75%) compared with in 2003 (85%, P < .01); behavior varied significantly according to the form of the statement. Peanut protein was detected in 10% (20/200) of total food products bearing advisory statements, although clinically significant levels of peanut (>1 mg of peanut or >0.25 mg of peanut protein) were detected in only 13 of 200 such products.

CONCLUSION

Consumers with food allergy are increasingly ignoring advisory labeling. Because food products with advisory labeling do contain detectable levels of peanuts, a risk exists to consumers choosing to eat such foods. The format of the labeling statement did not influence the likelihood of finding detectable peanut, except for products listing peanuts as a minor ingredient, but did influence the choices of consumers with food allergy.

CLINICAL IMPLICATIONS

Allergic patients are taking risks by increasingly disregarding advisory labeling.

Food allergy in gastroenterologic diseases: Review of literature

Food allergy is a common and increasing problem worldwide. The newly-found knowledge might provide novel experimental strategies, especially for laboratory diagnosis. Approximately 20% of the population alters their diet for a perceived adverse reaction to food, but the application of double-blind placebo-controlled oral food challenge, the “gold standard” for diagnosis of food allergy, shows that questionnaire-based studies overestimate the prevalence of food allergies. The clinical disorders determined by adverse reactions to food can be classified on the basis of immunologic or nonimmunologic mechanisms and the organ system or systems affected. Diagnosis of food allergy is based on clinical history, skin prick tests, and laboratory tests to detect serum-food specific IgE, elimination diets and challenges. The primary therapy for food allergy is to avoid the responsible food. Antihistamines might partially relieve oral allergy syndrome and IgE-mediated skin symptoms, but they do not block systemic reactions. Systemic corticosteroids are generally effective in treating chronic IgE-mediated disorders. Epinephrine is the mainstay of treatment for anaphylaxis. Experimental therapies for IgE-mediated food allergy have been evaluated, such as humanized IgG anti-IgE antibodies and allergen specific immunotherapy.