Determination of food specific IgE levels over time can predict the development of tolerance in cow's milk and hen's egg allergy

Predicting the Outcome of Pediatric Oral Food Challenges for Determining Tolerance Development

PURPOSE

Despite the risk of anaphylaxis, oral food challenges (OFCs) are performed clinically for various indications, particularly to confirm tolerance development. This study aimed to assess OFCs by relevant indications and build an outcome prediction model to help determine when to perform OFCs in children who are likely to have developed immune tolerance.

METHODS

In total, 432 pediatric OFCs were retrospectively analyzed according to indications. Clinical characteristics, serum total immunoglobulin (Ig) E, blood eosinophils, and specific IgE and IgG4 levels for food allergens were noted and compared. Machine learning was utilized to select the most important variables in determining the passage of the OFCs, and prediction models were constructed using the selected variables.

RESULTS

OFCs were most commonly performed to confirm tolerance development (number, %; 267, 61.8%). The most common food allergens tested were egg (191, 44.2%) and milk (135, 31.3%). Children who passed the egg challenges for confirming tolerance acquisition had significantly lower egg white-specific IgE level (P = 0.008). Similarly, those who passed milk challenges had significantly lower cow's milk-specific IgE (P = 0.002) and casein-specific IgE levels (P = 0.005). We developed a nomogram to predict the outcome of OFCs to determine the tolerance acquisition with the selected variables; lower food-specific IgE, higher total IgE, and younger age indicated a higher probability of passage. The area under the curve (95% confidence interval) was 0.623 (0.503-0.743) for egg and 0.734 (0.628-0.840) for milk.

CONCLUSIONS

Serum total IgE and food-specific IgE combined with age showed trends toward passing OFCs for confirming tolerance development. The constructed model may be used by clinicians as a practical guide for minimizing the risks of OFCs and a timely reintroduction for children with food allergies.

The Remaining Challenge to Diagnose and Manage Cow's Milk Allergy: An Opinion Paper to Daily Clinical Practice

Guidelines and recommendations for the diagnosis and management of cow's milk allergy (CMA) in childhood are based on scientific review of the available evidence. While this approach is the most rigorous, guidelines may not fully address all scenarios encountered by clinicians. Many symptoms of CMA overlap with other common childhood illnesses and are subjectively reported by the caregivers of the infant, as is the interpretation of the dietary interventions. Additionally, many healthcare professionals and caregivers do not follow the recommendations to perform an oral food challenge or reintroduction of cow's milk after a diagnostic elimination diet because (1) the infant is doing well and (2) the carer's fear of symptoms relapsing with this procedure. As a result, CMA in infants may be either under-diagnosed leading to reduced quality of life for families or over-diagnosed, resulting in unnecessary long-term elimination diets and increasing the risk for nutritional deficiencies. This paper discusses some of these controversial topics, focusing on misdiagnosis and mismanagement in clinical practice. The lack of objective diagnostic criteria can hamper the diagnosis and management of CMA in daily practice.

The Effect of Food Allergen Exclusion on the Growth of Saudi Children

With a variety of symptoms that can impede children's development, food allergies are an important public health concern. With the help of information from the King Fahad Medical City Hospital in Riyadh, we looked at how restricting certain foods affected the growth of Saudi children who had food allergies. An anonymous self-administered questionnaire asking about the individuals' demographics and their restricted eating habits was completed by 72 children (48 boys and 24 girls) between the ages of 2 and 14. The sensitivity of six allergens (hen eggs, cow milk, fish, wheat, peanuts, and soybeans), anthropometric indices, specific Immunoglobulin E (IgE) levels, and sensitivity were examined. The Statistical Package for Social Science (SPSS), version 26, was used to analyze the data. Chi-square and t-tests were used to examine the relationships between various category variables. According to the findings, most of the mothers of the children were between the ages of 30 and 40 (80.6%), had a college degree (72.3%), were unemployed (59.7%), and had a monthly family income between 5000 and 15,000 SAR (69.4%). Both sexes had specific IgE antibodies for allergens in classes 2 and 3, with boys having noticeably (p ≤ 0.05) higher quantities than girls. While females were more sensitive to fish and peanuts, boys were more likely than girls to show specific IgE sensitivity to egg white, cow milk, wheat, and soybeans. Both sexes' allergy levels were considerably (p ≤ 0.01) higher in children aged 5.01 to 10 than in other age groups. In terms of classifications of thinness, overweightness, and obesity, boys were slenderer than girls, and a greater percentage of boys than girls were overweight or obese. The exclusion of hen eggs, cow milk, wheat, and peanuts from the diet had a significant and detrimental effect on body mass index (BMI) and height-for-age ratio among children with impaired growth, in contrast to the demographic factors, which had a significant and favorable effect on the growth of other children. In conclusion, restrictions on food allergens impairs growth in Saudi children, particularly boys' growth.

EAACI Molecular Allergology User's Guide 2.0

Since the discovery of immunoglobulin E (IgE) as a mediator of allergic diseases in 1967, our knowledge about the immunological mechanisms of IgE-mediated allergies has remarkably increased. In addition to understanding the immune response and clinical symptoms, allergy diagnosis and management depend strongly on the precise identification of the elicitors of the IgE-mediated allergic reaction. In the past four decades, innovations in bioscience and technology have facilitated the identification and production of well-defined, highly pure molecules for component-resolved diagnosis (CRD), allowing a personalized diagnosis and management of the allergic disease for individual patients. The first edition of the "EAACI Molecular Allergology User's Guide" (MAUG) in 2016 rapidly became a key reference for clinicians, scientists, and interested readers with a background in allergology, immunology, biology, and medicine. Nevertheless, the field of molecular allergology is moving fast, and after 6 years, a new EAACI Taskforce was established to provide an updated document. The Molecular Allergology User's Guide 2.0 summarizes state-of-the-art information on allergen molecules, their clinical relevance, and their application in diagnostic algorithms for clinical practice. It is designed for both, clinicians and scientists, guiding health care professionals through the overwhelming list of different allergen molecules available for testing. Further, it provides diagnostic algorithms on the clinical relevance of allergenic molecules and gives an overview of their biology, the basic mechanisms of test formats, and the application of tests to measure allergen exposure.

Soluble IgE-binding factors in the serum of food-allergic patients: Possible pathophysiological role of soluble FcεRI as protective factor

BACKGROUND

IgE-mediated food allergy is the result of an aberrant immune response involving the interaction of a food allergen with its specific IgE bound to FcɛRI, the high affinity IgE receptor, on mast cells. Allergen-specific IgE also binds to soluble binding factors, but, their expression and role in food allergy is not well characterized. Here, we assess the prevalence and relevance of soluble IgE binding factors in food allergy and tolerance.

METHODS

We measured serum levels of four IgE binding factors, that is, galectin-3, galectin-9, soluble FcɛRI (sFcεRI) and soluble CD23 (sCD23) in 67 adults sensitized to peanut or hazelnut and sFcɛRI in 29 children sensitized to hen's egg. Adults without food allergen sensitization (n = 17) served as healthy controls. We compared serum levels of patients and controls and assessed them, in the former, for links to clinical features including allergy and tolerance.

RESULTS

Serum levels of sFcɛRI and sCD23, but not galectin-3 and galectin-9, significantly differ in food-sensitized patients as compared to healthy controls. A subgroup (28%) of peanut and hazelnut allergic patients had elevated sFcεRI levels, that were associated with higher total and specific IgE levels. Furthermore, sFcεRI levels were significantly higher in tolerant subjects compared to allergics. Among hazelnut allergic patients, those with high sFcεRI levels tolerated the highest protein amounts in the oral food challenge.

CONCLUSION

sFcɛRI but not sCD23, galectin-3 and galectin-9 might play a role in the pathophysiology of food allergy. Its functional role or use as biomarker should be assessed in further studies.

IgE and IgG4 Epitope Mapping of Food Allergens with a Peptide Microarray Immunoassay

Peptide microarrays are a powerful tool to identify linear epitopes of food allergens in a high-throughput manner. The main advantages of the microarray-based immunoassay are as follows: the possibility to assay thousands of targets simultaneously, the requirement of a low volume of serum, the more robust statistical analysis, and the possibility to test simultaneously several immunoglobulin subclasses. Among them, the last one has a special interest in the field of food allergy, because the development of tolerance to food allergens has been associated with a decrease in IgE and an increase in IgG4 levels against linear epitopes. However, the main limitation to the clinical use of microarray is the automated analysis of the data. Recent studies mapping the linear epitopes of food allergens with peptide microarray immunoassays have identified peptide biomarkers that can be used for early diagnosis of food allergies and to predict their severity or the self-development of tolerance. Using this approach, we have worked on epitope mapping of the two most important food allergens in the Spanish population, cow's milk, and chicken eggs. The final aim of these studies is to define subsets of peptides that could be used as biomarkers to improve the diagnosis and prognosis of food allergies. This chapter describes the protocol to produce microarrays using a library of overlapping peptides corresponding to the primary sequences of food allergens and data acquisition and analysis of IgE and IgG4 binding epitopes.

Risk factors for failing a repeat oral food challenge in preschool children with hen's egg allergy

BACKGROUND

Children with hen's egg (HE) allergy and a positive initial oral food challenge (OFC) require rechallenge to assess for tolerance. However, the risk factors for a positive repeat OFC remain unclear.

METHODS

We retrospectively analyzed data from 243 preschool children who failed an initial OFC with half a heated HE and repeated the same OFC after 6-24 months. Logistic regression models were used to determine risk factors for a positive repeat OFC, including factors that were ascertainable immediately after the initial OFC and at the repeat OFC as variables.

RESULTS

The median age, egg white-, and ovomucoid-specific IgE (sIgE) were 3.5 years, 12.7, and 7.2 kU_A /L, respectively. The median interval between OFCs was 12.4 months and repeat OFCs were positive in 132 (54%) patients. One multivariate analysis model indicated that risk factors for a positive repeat OFC included cumulative dose (adjusted odds ratio [aOR]:0.58), anaphylaxis (aOR: 3.09), total serum IgE (aOR: 0.41), ovomucoid-sIgE (aOR: 3.21), and age (aOR: 1.68) at the initial OFC. Another model indicated that the risk factors were cumulative dose (aOR: 0.59) and anaphylaxis (aOR: 3.41) at initial OFC and total serum IgE (aOR: 0.36), ovomucoid-sIgE (aOR: 4.93), and age (aOR: 1.30) at repeat OFC.

CONCLUSION

Low threshold dose and severe symptoms at initial OFC, and low total serum IgE, high ovomucoid-sIgE and higher age at initial and repeat OFCs are risk factors for the persistence of HE allergy and they may be useful when deciding the rechallenge interval for heated HE in preschool children.

Oral Immunotherapy for Children with Cow's Milk Allergy: A Practical Approach

Cow milk allergy (CMA) is a prevalent disease in childhood. Natural history is usually favorable as CMA can disappear by school age in many subjects. Diagnosis corresponds to treatment, as an elimination diet is a solution. However, cow's milk (CM) is real food, hardly replaceable. Thus, CM reintroduction represents a demanding challenge in clinical practice. The induction of CM tolerance could be achievable using oral immunotherapy (OIT), such as the administration of increasing milk quantities until reaching tolerance. However, the OIT schedule and procedure need to be better standardized, and performance may vary widely. Therefore, the present study reports the practical experience of a third-level pediatric allergy center in managing children with CMA and submitting them to OIT. OFC and OIT are relatively safe procedures as the reaction rate is low. Almost two-thirds of the OIT subjects tolerated CM. Reactions were associated with high IgE levels. Therefore, the present experience, developed by a qualified center, may suggest and propose a practical approach for managing children with CMA. After the initial workup, including a thorough history, physical examination, and laboratory tests, OFC and, when indicated, OIT could be performed in most children with CMA.

Peanut allergy in Italy: A unique Italian perspective

Background

Peanut allergy has not been well characterized in Italy.

Objective

Our aim was to better define the clinical features of peanut allergy in Italy and to detect the peanut proteins involved in allergic reactions.

Methods

A total of 22 centers participated in a prospective survey of peanut allergy over a 6-month period. Clinical histories were confirmed by in vivo and/or in vitro diagnostic means in all cases. Potential risk factors for peanut allergy occurrence were considered. Levels of IgE to Arachis hypogea (Ara h) 1, 2, 3, 6, 8, and 9 and profilin were measured.

Results

A total of 395 patients (aged 2-80 years) were enrolled. Of the participants, 35% reported local reactions, 38.2% reported systemic reactions, and 26.6% experienced anaphylaxis. The sensitization profile was dominated by Ara h 9 (77% of patients were sensitized to it), whereas 35% were sensitized to pathogenesis-related protein 10 (PR-10) and 26% were sensitized to seed storage proteins (SSPs). Sensitization to 2S albumins (Ara h 2 and Ara h 6) or lipid transfer protein (LTP) was associated with the occurrence of more severe symptoms, whereas profilin and PR-10 sensitization were associated with milder symptoms. Cosensitization to profilin reduced the risk of severe reactions in both Ara h 2- and LTP-sensitized patients. SSP sensitization prevailed in younger patients whereas LTP prevailed in older patients (P < .01). SSP sensitization occurred mainly in northern Italy, whereas LTP sensitization prevailed in Italy's center and south. Atopic dermatitis, frequency of peanut ingestion, peanut consumption by other family members, or use of peanut butter did not seem to be risk factors for peanut allergy onset.

Conclusions

In Italy, peanut allergy is rare and dominated by LTP in the country's center and south and by SSP in the north. These 2 sensitizations seem mutually exclusive. The picture differs from that in Anglo-Saxon countries.

Total serum IgE levels as predictor of the acquisition of tolerance in children with food allergy: Findings from a pilot study

BACKGROUND

The gold standard to diagnose food allergy (FA) is a double-blind, placebo-controlled food challenge (OFC), even if it shows potential risk of severe allergic reactions for the patient and is time-consuming. Therefore, easier, and less invasive methods are needed to diagnose FA and predict the tolerance, changing the clinical practice.

AIM

The main aim of this study was to assess whether the total IgE values at the diagnosis of FA were associated with the duration of the tolerance acquisition and thus of the food elimination diet.

METHODS

We retrospectively analyzed the medical records of 40 patients allergic to milk or egg who performed an OFC for the reintroduction of the causal food at the Pediatric Allergy and Respiratory Unit of the University of Chieti from January 2018 to December 2020.

RESULTS

We found a positive association of total serum IgE with the elimination diet duration (β = 0.152; CI, 95% 0.04-0.27) after adjusting for age, sex, and type of allergy (milk or egg). We also showed a significant correlation (r = 0.41 and p-value = 0.007) between the total IgE values and the duration of the elimination diet and a significant correlation between the casein specific IgE values at diagnosis of FA and the severity of the clinical presentation (r = 0.66; p-value 0.009).

CONCLUSION

Total serum IgE at baseline, along with the downward trend of food-specific IgE levels (to milk or egg), may be useful in the prognostication of natural tolerance acquisition.

Prognosis of food-induced anaphylaxis in children: A single-center real-life study

Background: Food allergies are known to resolve over time, but there is little information on the natural history of food-induced anaphylaxis (FIA). Objective: This study aimed to evaluate the natural history of FIA in children and determine the factors that affect prognosis. Methods: Children with FIA who were followed up for at least 3 years, between 2010 and 2020, were included. Patients' families were contacted by telephone to question their child's tolerance status and invite them for reevaluation if uncertain. The patients were grouped as tolerant or persistent according to parent reports or reevaluation results. Logistic regression analysis was performed to determine the factors that affected persistence. Results: The study included 185 patients (62.2% boys) with 243 anaphylactic reactions to various foods. Fifty-eight patients (31%) gained tolerance within a 3-year follow-up period. Tolerance rates were higher in patients with FIA to milk (40%) and egg (43.9%) compared with to tree nuts (18.8%), legumes (5.6%), and/or seafood (11.1%) (p < 0.001). In a multivariate analysis, risk factors for persistent FIA were multiple food anaphylaxis (odds ratio [OR] 3.755 [95% confidence interval {CI}, 1.134-12.431]; p = 0.030), total IgE > 100 kU/L (OR 5.786 [95% CI, 2.065-16.207]; p = 0.001), and skin-prick test wheal size > 10 mm (OR 4.569 [95% CI, 1.395-14.964]; p = 0 .012) at presentation. Conclusion: Approximately a third of the patients with FIA developed tolerance within 3 years. Clinicians should remember that children with food allergies, even anaphylaxis, may develop tolerance over time. Regular follow up and reevaluation of tolerance status are necessary to avoid unnecessary elimination.

Identification of predictors for persistence of immediate-type egg allergy in Chinese children

Background

Egg allergy is one of the most common food allergies in childhood with increasing prevalence in Hong Kong. While ample studies were published on its optimal diagnosis, there was limited data on predictors for the natural history of egg allergy in Asian populations.

Objective

This study aimed to characterize the clinical course and outcome of children with egg allergy and identify its prognostic factors.

Methods

All Chinese children with immediate-type egg allergy being followed since ≥3 years old in allergy clinic of our university-affiliated teaching hospital were reviewed to determine if they outgrew egg allergy at the latest follow-up. The predictive values of clinical and atopic factors for resolution of egg allergy were analyzed on Kaplan-Meier curves, and factors independently associated with persistent egg allergy was analyzed by logistic regression.

Results

Seventy-six patients with median (interquartile range) age 8.9 years (6.3–13.0 years) were recruited. They initially presented with egg-allergic reactions at 1.0 years (0.7–1.7 years). Fifty-four children (71%) were able to tolerate egg at a median of 36 months from initial reaction. Patients with concomitant peanut allergy and those with initial reaction at ≥1 year old were more likely to have persistent egg allergy (p = 0.015 and p = 0.027 respectively). Skin prick test wheal ≥6 mm to egg yolk and egg white individually as well as to both egg yolk and egg white were predictors for egg allergy persistence (respective, p < 0.001, p = 0.001, and p = 0.001 by log-rank tests). Logistic regression showed that initial SPT ≥ 6 mm to egg yolk was the only independent predictor for persistent egg allergy (B = 2.59 ± 0.98, p = 0.008).

Conclusion

Most Chinese children with immediate-type egg allergy can tolerate egg in long run. SPT wheal size to egg, concomitant peanut allergy and initial presentation after infancy may predict egg allergy persistence.

BSACI 2021 guideline for the management of egg allergy

This guideline advises on the management of patients with egg allergy. Most commonly egg allergy presents in infancy, with a prevalence of approximately 2% in children and 0.1% in adults. A clear clinical history will confirm the diagnosis in most cases. Investigation by measuring egg-specific IgE (by skin prick testing or specific IgE assay) is useful in moderate-severe cases or where there is diagnostic uncertainty. Following an acute allergic reaction, egg avoidance advice should be provided. Egg allergy usually resolves, and reintroduction can be achieved at home if reactions have been mild and there is no asthma. Patients with a history of severe reactions or asthma should have reintroduction guided by a specialist. All children with egg allergy should receive the MMR vaccine. Most adults and children with egg allergy can receive the influenza vaccine in primary care, unless they have had anaphylaxis to egg requiring intensive care support. Yellow Fever vaccines should only be considered in egg-allergic patients under the guidance of an allergy specialist. This guideline was prepared by the Standards of Care Committee (SOCC) of the British Society for Allergy and Clinical Immunology (BSACI) and is intended for allergists and others with a special interest in allergy. The recommendations are evidence based. Where evidence was lacking, consensus was reached by the panel of specialists on the committee. The document encompasses epidemiology, risk factors, diagnosis, treatment, prognosis and co-morbid associations.

Optimizing Patient Care in Egg Allergy Diagnosis and Treatment

Egg allergy occurs frequently in childhood with a reported prevalence of 1.3–1.6%. Providing optimal care to egg-allergic patients requires knowledge of the most up-to-date developments in both diagnosis and management, as well as effective communication skills, which will engage the patient in the shared decision-making process. This review aims to provide up-to-date information on egg allergy and also serve as a concise guide on optimal patient diagnosis and management. The field of food allergy has seen multiple advances in recent years, including use of component resolved diagnostics, early egg introduction into the infant diet as a way of preventing egg allergy, baked egg introduction and oral immunotherapy as a form of active therapy. Faced with a variety of options and treatment paths, it is important to ensure that patients and families taking part in the decision-making process have fully understood the potential outcomes and trade-offs and can undertake a detailed discussion of all options that are available to them. Shared decision-making remains the cornerstone of optimal patient care.

Improving Diagnostic Accuracy in Food Allergy

The diagnosis of food allergy can have a major impact on the lives of patients and families, imposing dietary restrictions and limitations on social activities. On the other hand, misdiagnosis can place the patient at risk of a potentially severe allergic reaction. Therefore, an accurate diagnosis of food allergy is of utmost importance. The diagnosis of food allergy is often established by the combination of the clinical history and allergen-specific IgE; however, without a clear history of an allergic reaction, the interpretation of IgE sensitization tests can be difficult. There are also rare cases of clinical food allergy in the absence of IgE sensitization. For that reason, testing for suspected food allergy ideally requires access to oral food challenges (OFCs), which are currently the gold standard tests to diagnose food allergy. As OFCs are time consuming and involve the risk of acute allergic reactions of unpredictable severity, the question remains: how can we improve the accuracy of diagnosis before referring the patient for an OFC? Herein, we review the predictive value of different tests used to support the diagnosis of food allergy, discuss implications for therapy and prognosis, and propose a diagnostic approach to be applied in clinical practice.

Food Allergy: Catering for the Needs of the Clinician

The practice of food allergy (FA) for clinicians has boomed, with a dramatic rise in the number of patients and families seeking care and with many advances on several fronts. The practice itself sometimes is evidence-based science and sometimes an art of pattern and phenotype recognition. This article examines the tools for diagnosis and management and therapy options available to physicians providing care for patients with FA. The article touches on pressing needs of clinicians and highlights the rapid and important movements in national and international support and advances that will have a positive impact on the field of FA.

Allergen detection and analysis in Eastern Taiwan area

Objective:

Environmental factors, eating habits, and different ages might affect the profiles of allergy sensitization. The purpose of this study was to survey the different profiles of allergen sensitization in different ages in eastern Taiwan.

Materials and Methods:

We analyzed the allergic patients who had allergen sensitization examinations by the Phadiatop (atopy screen; IBT Laboratories, Lenexa, KS, USA) and the Pharmacia CAP System method at Haulien Tzu Chi Hospital from January 2010 to December 2015. Results were compared in different ages.

Results:

A total of 15,455 patients were analyzed. The food and aeroallergen screen sensitization rate of children was significantly higher than that of adults (44.0% vs. 9.9% and 61.9% vs. 52.2% P < 0.05). Children had statistically significantly higher cow milk allergen-specific sensitization rate than that of adults (32.9% vs. 5.8% P < 0.05). The higher sensitization of shrimp occurred in adults than children. (33.6% vs. 24.8% P < 0.05).

Conclusion:

Our data demonstrate that children have higher cow milk allergy sensitization and adults have higher sensitization of shrimp.

Cow's Milk Protein Allergy as a Model of Food Allergies

Cow's milk allergy (CMA) is one of the most common food allergies in infants, and its prevalence has increased over recent years. In the present paper, we focus on CMA as a model of food allergies in children. Understanding the diagnostic features of CMA is essential in order to manage patients with this disorder, guide the use of an elimination diet, and find the best moment to start an oral food challenge (OFC) and liberalize the diet. To date, no shared tolerance markers for the diagnosis of food allergy have been identified, and OFC remains the gold standard. Recently, oral immunotherapy (OIT) has emerged as a new therapeutic strategy and has changed the natural history of CMA. Before this, patients had to strictly avoid the food allergen, resulting in a decline in quality of life and subsequent nutritional, social, and psychological impairments. Thanks to the introduction of OIT, the passive approach involving rigid exclusion has changed to a proactive one. Both the heterogeneity in the diagnostic process among the studies and the variability of OIT data limit the comprehension of the real epidemiology of CMA, and, consequentially, its natural history. Therefore, well-planned randomized controlled trials are needed to standardize CMA diagnosis, prevention, and treatment strategies.

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.

Stem Cell Factor Neutralization Protects From Severe Anaphylaxis in a Murine Model of Food Allergy

Food allergy is a growing public health problem with ~15 million people affected in the United States. In allergic food disease, IgE on mast cells bind to ingested antigens leading to the activation and degranulation of mast cells. Stem cell factor (SCF) is mast cell growth and activation factor that is required for peripheral tissue mast cells. We targeted a specific isoform of SCF, the larger 248 amino acid form, that drives peripheral tissue mast cell differentiation using a specific monoclonal antibody in a model of food allergy. Ovalbumin sensitized and intragastrically challenged mice were monitored for symptoms of anaphylaxis including respiratory distress, diarrhea, and a reduction in body temperature. During the second week of challenges, allergic mice were injected with an antibody to block SCF248 or given IgG control. Mice treated with α-SCF248 had a decreased incidence of diarrhea and no reduction in body temperature suggesting a reduction in anaphylaxis compared to IgG control treated animals. Re-stimulated mesenteric lymph nodes indicated that α-SCF248 treated mice had decreased OVA-specific Th2 cytokine production compared to IgG control treated allergic animals. The reduction of food induced anaphylaxis was accompanied by a significant reduction in gut leak. The mesenteric lymph node cells were analyzed by flow cytometry and showed a decrease in the number of type 2 innate lymphoid cells in mice injected with α-SCF248. Morphometric enumeration of esterase+ mast cells demonstrated a significant reduction throughout the small intestine. Using a more chronic model of persistent food-induced anaphylaxis, short term therapeutic treatment with α-SCF248 during established disease effectively blocked food induced anaphylaxis. Together, these data suggest that therapeutically blocking SCF248 in food allergic animals can reduce the severity of food allergy by reducing mast cell mediated disease activation.

Biomarkers of diagnosis and resolution of food allergy

Food allergy is increasing in prevalence, affecting up to 10% of children in developed countries. Food allergy can significantly affect the quality of life and well-being of patients and their families; therefore, an accurate diagnosis is of extreme importance. Some food allergies can spontaneously resolve in 50%-60% of cow's milk and egg-allergic, 20% of peanut-allergic and 9% of tree nut-allergic children by school age. For that reason, food-allergic status should be monitored over time to determine when to reintroduce the food back into the child's diet. The gold-standard to confirm the diagnosis and the resolution of food allergy is an oral food challenge; however, this involves the risk of causing an acute-allergic reaction and requires clinical experience and resources to treat allergic reactions of any degree of severity. In the clinical setting, biomarkers have been used and validated to enable an accurate diagnosis when combined with the clinical history, deferring the oral food challenge, whenever possible. In this review, we cover the tools available to support the diagnosis of food allergies and to predict food allergy resolution over time. We review the latest evidence on different testing modalities and how effective they are in guiding clinical decision making in practice. We also evaluate predictive test cut-offs for the more common food allergens to try and provide guidance on when challenges might be most successful in determining oral tolerance in children.

Agreement Between Predictive, Allergen-Specific IgE Values Assessed by ImmunoCAP and IMMULITE 2000 3gAllergy™ Assay Systems for Milk and Wheat Allergies

Purpose

ImmunoCAP^® (ImmunoCAP) and IMMULITE^® 2000 3gAllergy™ (3gAllergy) systems are major quantitative allergen-specific immunoglobulin E (sIgE) assay methods. Due to the heterogeneous nature of allergenic extracts and differences in the assay format, quantitation of allergen-sIgEs is not expected to correlate well between different methods. However, we have recently reported good agreement between the methods in the diagnosis of egg allergy. This study aimed to determine and correlate the predictive values of sIgE by the two systems in the diagnosis of milk and wheat allergies.

Methods

Children who had undergone oral food challenge (OFC) for the diagnosis of milk and wheat allergies were enrolled. The OFCs were performed to diagnose either true allergy in the 1-year-old group (A) or tolerance in the 2- to 6-year-old group (B). Milk, casein and β-lactoglobulin, and wheat and ω-5 gliadin sIgE values were measured using the 2 systems. The predictive accuracy of each sIgE for the OFC outcome was assessed using receiver operating characteristic (ROC) curves. The probability of a positive OFC outcome was estimated by logistic regression analysis.

Results

A total of 395 patients were recruited from 7 primary care clinics and 19 hospitals in Japan. Milk and wheat OFCs were performed for 87 and 102 group A patients, and 124 and 82 group B patients, respectively. ROC analysis yielded similar areas under the curve for the 2 assays (0.7–0.9). The log-transformed sIgE data showed a strong linear correlation with the estimated probabilities (R > 0.9).

Conclusions

The 2 systems may be interchangeable for diagnosis of milk and wheat allergies in young children.

Effect of Low-Immunogenic Yogurt Drinks and Probiotic Bacteria on Immunoreactivity of Cow's Milk Proteins and Tolerance Induction-In Vitro and In Vivo Studies

There is no effective therapy for milk allergy. The role of lactic acid bacteria (LAB) and probiotics in protection against allergy-related outcomes is still under investigation. The aim of the study was to evaluate the immunomodulative and therapeutic potential of yogurt drinks in cow's milk allergy (CMA) management. We compared immunoreactivity of α-casein (α-CN), β-casein (β-CN), κ-casein (κ-CN), α-lactalbumin (α-LA), and β-lactoglobulin (β-LG) in 27 yogurt drinks fermented with different basic yogurt cultures, or yogurt cultures enriched with Lactobacillus plantarum and/or Bifidobacterium lactis strains, by competitive ELISA assay. Drinks with the lowest antigenic potential were used as allergoids for CMA therapy. BALB/c mice were sensitized via intraperitoneal injection of α-CN + β-LG mixture with aluminum adjuvant, and gavaged with increasing doses of selected low-immunogenic drinks (YM-basic, or YM-LB-enriched with L. plantarum and B. lactis) to induce tolerance. Milk- or phosphate-buffered saline (PBS)-dosed mice served as controls. Compared to milk, the immunoreactivity of proteins in drinks increased or decreased, depending on the bacterial sets applied for fermentation. Only a few sets acted synergistically in reducing immunoreactivity. The selected low-immunogenic drinks stimulated allergic mice for profiling Th2 to Th1 response and acquire tolerance, and the effect was greater with YM-LB drink, which during long-lasting interventional feeding strongly increased the secretion of regulatory cytokines, i.e., IL-10 and TGF-β, and IgA and decreased IL-4, IgE, and anti-(α-CN + β-LG) IgG1. The studies revealed variations in the potency of yogurt bacteria to change allergenicity of milk proteins and the need for their strict selection to obtain a safe product for allergy sufferers. The YM-LB drink with reduced antigenic potential may be a source of allergoids used in the immunotherapy of IgE mediated CMA, but further clinical or volunteer studies are required.

Utility of fresh egg skin prick test and egg yolk specific immunoglobulin E for outgrowth

BACKGROUND

In children younger than 2 years, studies evaluating the value of skin prick tests (SPTs) and specific immunoglobulin E (sIgE) results to predict persistence or resolution of egg allergy (EA) are limited. In addition, the value of egg yolk (EY) sIgE and fresh egg (FE) SPTs has not been well characterized.

OBJECTIVE

To investigate the optimal decision points (ODPs) for outgrowing allergy with SPTs and sIgE tests for egg allergen preparations.

METHODS

SPTs for FE, egg white (EW), and EY, sIgE tests for EW and EY, and oral food challenges (OFCs) were performed in children with suspected EA. Reactive patients strictly avoided all dietary egg. After 1 year, EA was reevaluated with addition OFCs, SPTs, and sIgE tests.

RESULTS

A total of 81 children (median age, 7 months; age range, 2-24 months) were enrolled. Notably, 4 children with a history of anaphylaxis and 60 of 77 children with a positive challenge result underwent egg elimination. The 1-year follow-up OFC test was performed on 59 children. A total of 27 reacted to egg. No persistent patient had a follow-up SPT result for FE of 4 mm or less (positive predictive values of 100% and negative predictive value of 56% for outgrowth). The diameters of the initial SPT for FE decreased 50% or more in half of the patients who outgrew EA. The ODPs for outgrowing allergy for follow-up sIgE tests for EY and EW were 2.1 kU/L or less (positive predictive value of 86.2%) and 4.0 kU/L or less (positive predictive value of 84.6%), respectively.

CONCLUSION

A SPT diameter for FE of 4 mm or less and sIgE values of 2.1 kU/L or less for EY and 4.0 kU/L or less for EW have a good positive predictive value for outgrowth of EA in children younger than 2 years.

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.

Assessment of IgE-Mediated and Non-IgE-Mediated Cow’s Milk Protein Allergy in Children

Cow’s milk protein allergy (CMPA) is the most common food allergy found in children under 3 years of age. In most cases, it occurs in infancy. Early diagnosis and appropriate treatment can decrease the risk of impaired growth.

In our study, we evaluated 40 children, with ages between 1 month and 3 years, diagnosed with IgE-mediated or non-IgE-mediated CMPA, from january to december 2017, in the Department of Pediatrics of the Clinical Emergency County Hospital of Constanta.

The inclusion criteria consisted of: age, natural or artificial feeding, specific IgE levels, CoMiSS score, and clinical manifestations. The Cow’s Milk-related-Symptom-Score (CoMiSS) was developed as a screening and diagnostic tool for CMPA prediction, and can guide pediatricians and primary care physicians to make an early diagnostic, as it can be easily missed.

We observed a higher number of cases of CMPA registered among children who were artificially fed (57,5%), followed by those with mixed nutrition (25%), the remaining (17,5%) being represented by exclusively breastfed infants. The most frequent clinical manifestations were rashes (87,5%), failure to thrive (82,5%), regurgitation (50%) and diarrhea (35%).

Further data should be collected to prove if the association between a CoMiSS score higher than 12 and specific IgE-mediated CMPA is clinically relevant, and can predict, based on clinical examination and anamnesis, high serum levels of specific immunoglobulin E.

The prognosis can depend on the titre of specific IgE at the time of diagnosis, as they are more likely to develop several crossed allergies and less prone to become tolerant to cow milk proteins than those with non-IgE-mediated CMPA.

Prevalence and natural history of tree nut allergy

OBJECTIVE

Tree nuts are common causes of food-related allergic reactions and anaphylaxis. Resolution of tree nut allergy is thought to be low, yet studies of the natural history of tree nut allergy are limited. This review summarizes the available literature regarding tree nut allergy prevalence and natural history and discusses emerging diagnostic and prognostic developments that will inform clinical management of tree nut allergy.

DATA SOURCES

A comprehensive literature search using PubMed was performed.

STUDY SELECTIONS

Peer-reviewed publications relating to tree nut allergy prevalence, resolution, and diagnosis were selected, and findings were summarized using a narrative approach.

RESULTS

Tree nut allergy prevalence varies by age, region, and food allergy definition, and ranges from less than 1% to approximately 3% worldwide. Reports on the natural history of tree nut allergy data are limited to retrospective clinical data or cross-sectional survey data of self-reported food allergy, with reported resolution ranging from 9% to 14%. Component-resolved diagnostics and basophil activation testing offer the potential to improve the diagnostic accuracy and predicted prognosis of specific tree nut allergy, but studies are limited.

CONCLUSION

Tree nut allergy remains an understudied area of food allergy research with limited region-specific studies based on robust food allergy measures in population cohorts with longitudinal follow-up. This currently limits our understanding of tree nut allergy prognosis.

The Natural Course of Immediate-Type Cow's Milk and Egg Allergies in Children

BACKGROUND

Most of children with cow's milk (CM) and hen's egg allergies are known to outgrow their diseases with time, but recent studies have demonstrated that children tend to continue to have allergic symptoms in adolescence and adulthood. The aim of this study was to investigate the natural course of CM and egg allergies in Korean children and analyze prognostic factors.

METHODS

In this retrospective study, we reviewed data of children with CM allergy and with egg allergy using medical records and parental telephone interviews. Diagnosis of CM or egg allergy was based on positive oral food challenge test or convincing history of allergic symptoms in combination with positive allergen-specific IgE. Acquisition of tolerance was defined by the absence of allergic symptoms after reintroduction of the offending foods.

RESULTS

Half of the children outgrew CM allergy at a median age of 8.7 years. CM-specific IgE level at the first reaction was a significant prognostic factor for oral tolerance in CM allergy (p < 0.05). The median age to acquire oral tolerance in 50% of patients with egg allergy was 5.6 years. Egg-specific IgE level at the first reaction and family history of allergic diseases significantly affected the prognosis in children with egg allergy (p < 0.05).

CONCLUSIONS

Half of Korean children with CM and egg allergies had symptom resolution at 8.7 and 5.6 years of age, respectively. Our results also suggest that CM- and egg-specific IgE levels at the first reaction are the most significant prognostic factors in predicting acquisition of oral tolerance.

Predicting outgrowth of IgE-mediated cow's milk allergy: Diagnostic tests in children under two years of age

BACKGROUND

Limited studies conducted on children <2 years old and/or involving a skin prick test (SPT) for fresh milk (FM) have examined the predictive value of allergometric tests for outgrowth of cow's milk allergy (CMA). We investigated the optimal decision points for outgrowth (ODP^fo) with SPT for commercial cow's milk extract (CE) and FM and specific immunoglobulin E (sIgE) levels for milk proteins to predict outgrowing allergy in children <2 years old.

METHODS

SPTs for CE and FM, tests for sIgEs (cow's milk, casein, α-lactoalbumin, β-lactoglobulin) and oral food challenges (OFC) were performed in children referred for evaluation of suspected CMA, and 15 months after diagnosis.

RESULTS

Fifty-one children (median age, 7.5 months; range, 2-23 months) were enrolled. Five had a history of anaphylaxis and 26 of 48 children with a positive initial challenge underwent milk elimination. The last OFC was performed in 28 children of whom 13 reacted to milk. The initial SPT responses to CE and FM and milk sIgE levels of the patients with persistent CMA were higher at diagnosis, with ODP^fo of 7mm, 9mm, and 10.5kU/L, respectively; these values remained higher with ODP^fo of 4mm, 11mm, and 10.5kU/L at the last OFC.

CONCLUSION

Higher initial SPTs for FM and CE and higher initial sIgE levels for cow's milk proteins are associated with a reduced likelihood of outgrowth. Initial milk sIgE level <10.5kU/L and initial SPT for fresh milk <9mm are related to the acquisition of tolerance in the follow-up period.

Food Allergen Sensitisation Patterns in Omani Patients with Allergic Manifestations

Objectives

This study aimed to evaluate the relationship between food allergen sensitisation patterns and allergic manifestations in Omani patients and highlight the importance of specific immunoglobulin E (IgE) testing.

Methods

This retrospective study included all patients referred due to allergic manifestations to the Sultan Qaboos University Hospital (SQUH), Muscat, Oman, from November 2012 to November 2016. Specific IgE blood testing was performed to determine sensitisation to common foods known to cause allergic reactions.

Results

A total of 164 patients were referred to SQUH over the study period, with 35.4% presenting with one allergic manifestation, 48.8% with 2-3 and 15.9% presenting with more than three manifestations. There was a family history of allergies in 70.7% of patients. Eosinophil counts and total and specific IgE levels were elevated in 18.9%, 54.9% and 73.2% of patients, respectively. Patients demonstrated sensitisation to cow milk (47.6%), wheat (41.5%), chicken eggs (34.8%), mixed tree nuts (34.1%), lentils (33.5%), peanuts (32.9%), soy (32.3%), shrimp (23.2%) and fish (15.2%). Overall, 19.5% were sensitised to a single allergen, 14% were sensitised to 2-3 and 39.6% were sensitised to more than three allergens. Almost one-third (29.3%) of patients suffered from food-induced anaphylaxis, of which 85.4% were prescribed self-injectable adrenaline.

Conclusion

To the best of the authors' knowledge, this study is the first to describe food allergen sensitisation patterns among Omani patients with allergic manifestations. In conjunction with clinical symptoms, the correct interpretation of specific IgE levels is important to diagnose food allergies and make safe decisions about reintroducing foods.

Successful oral desensitization in children with cow's milk anaphylaxis: Clinical and laboratory evaluation up to nine-years follow-up

INTRODUCTION

Cow's milk protein allergy (CMPA) is the most common food allergy in children worldwide. Some children have severe and persistent CMPA, with near-fatal reactions after exposure to trace amounts of cow's milk-proteins (CMP). Strict avoidance diet is difficult, negatively affects quality of life and represents a conservative approach. Therefore, different therapeutic strategies are necessary.

OBJECTIVE

We aimed to assess long-term efficacy and safety of oral immunotherapy (OIT) in children with severe and long-lasting IgE-mediated CMPA.

MATERIALS AND METHODS

The authors present four case reports of patients with CMPA who underwent CMP-OIT, that have been under long-term follow-up up to nine years. We provide information about the clinical and laboratory evaluation. Skin prick tests (SPT), specific IgE and IgG4 were performed before, during, and after OIT. Immune profile after OIT was assessed by flow cytometry (lymphocyte subsets, regulatory T and B cells).

RESULTS

The success rate was 100%, and all patients currently have a free diet with minimal diary ingestion of 200mL CMP or equivalent. Specific IgE levels and SPT to CMP have progressively decreased, and specific IgG4 levels have increased. CD4⁺CD25⁺CD127^-/dim regulatory T cells were increased after OIT.

CONCLUSIONS

OIT ensured a clinical tolerance state after up to nine years, confirmed by both clinical and immune profile, allowing a diet without restrictions, with high satisfaction from patients and caregivers. We emphasize that OIT should be performed only by allergy experts in the hospital setting, and that only motivated families should be enrolled, since it is essential to ensure CMP daily intake at home.

Current Trends in Tolerance Induction in Cow's Milk Allergy: From Passive to Proactive Strategies

This review addresses the current strategies of inducing tolerance development in infant and childhood cow's milk protein allergy (CMPA). The change in prevention strategies for CMPA has been emphasized based on the lack of evidence to support the efficacy of food allergen avoidance in infancy and the concept of the dual-allergen-exposure hypothesis, which suggests that allergen exposure through the skin leads to sensitization, whereas early oral consumption of allergenic food protein induces oral tolerance. The new approach is based on the likelihood of early introduction of allergenic foods to the infant's diet to reduce the development of food allergies through oral tolerance induction. The latest treatment guidelines recommend the continuation of breast feeding and the elimination of cow's milk and products from the maternal diet in exclusively breast-fed infants with CMPA, the use of an extensively hydrolyzed infant formula (eHF) with proven efficacy in CMPA as the first elimination diet in formula-fed infants with CMPA and the use of amino acid-based formula (AAF) in severe cases, such as anaphylaxis, enteropathy, eosinophilic esophagitis, and food protein-induced enterocolitis syndrome (FPIES), as well as cases of multiple system involvement, multiple food allergies, and intolerance to extensively hydrolyzed formula (eHF). In conclusion, this paper presents the current knowledge on tolerance development in infants and children with CMPA to increase the awareness of the clinicians concerning the new approaches in CMPA treatment Tolerance development is considered a relatively new concept in CMPA, inducing a shift in interventions in CMPA from a passive (avoidance of responsible allergen) toward a proactive (tolerance induction) strategy.

Reduction Rate of Specific IgE Level as a Predictor of Persistent Egg Allergy in Children

PURPOSE

Egg is the most common food allergen in infants. However, the natural course of egg allergy has not been fully elucidated. This study aimed to describe clinical characteristics and to identify prognostic factors associated with tolerance acquisition of immunoglobulin E (IgE)-mediated egg allergy in children.

METHODS

Children who underwent more than 1 follow-up egg white-specific immunoglobulin E (EWsIgE) test between November 2005 and November 2015 at -Severance Children's Hospital were assessed. Children were diagnosed as having IgE-mediated egg allergy based on immediate allergic reaction after egg consumption and an EWsIgE level of > 0.35 kU/L. The children were divided into "tolerant" and "persistent" groups according to tolerance acquisition defined as egg consumption without adverse allergic reactions.

RESULTS

Of 124 participants, egg allergy resolved in 101 (81.5%) children. The persistent group had more atopic dermatitis (P = 0.039), and more wheat (P = 0.009) and peanut (P = 0.012) allergies compared to the tolerant group. The EWsIgE levels at diagnosis (EWsIgE_diag) were higher in the persistent group than in the tolerant group (P = 0.001). The trend of the EWsIgE levels in the tolerant group decreased markedly over time compared to the persistent group (P < 0.001). In predicting egg allergy tolerance acquisition, the reduction rate of EWsIgE level after 12 months from diagnosis (ΔEWsIgE_12mo) tended to be more accurate than EWsIgE_diag (area under the curve: 0.835 vs. 0.731). When ΔEWsIgE_12mo was ≥ 30%, tolerance acquisition was more frequent than that of < 30% (91.9% vs. 57.9%; P < 0.001).

CONCLUSIONS

ΔEWsIgE_12mo can be used as an early independent predictor of tolerance acquisition of IgE-mediated egg allergy in children.

Independent predictive factors for the persistence and tolerance of cow's milk allergy

BACKGROUND

Cow's milk protein allergy (CMPA) is usually transient, with most children tolerating ingested cow's milk by 3 years of age. This study aimed to determine factors that promote or hindering the development of tolerance to CMPA.

METHODS

A logistic regression model was used to determine independent risk factors associated with tolerance and persistence of CMPA.

RESULT

A total of 178 children diagnosed with CMPA were included in the study. The patients' median age was 32 months (minimum-maximum, 14 to 144 months), and their median follow-up period was 30 months (minimum-maximum, 12 to 54 months). In the follow-up, CMPA persisted in 62 (34.8%) patients. The patients were divided into 2 groups according to patient's age. Group I was <3 years old and group II was ≥3 years old. The factors independently associated with the persistence of CMPA for group I were as follows: comorbid food allergies (p = 0.021), the presence of an immunoglobulin E (IgE)-mediated reaction (p = 0.001), and respiratory system symptoms (ie, tachypnea) (p = 0.036). The presence of gastrointestinal-related discomfort (p = 0.001) was an independent risk factor associated with the development of tolerance. The presence of comorbid food allergies (p = 0.03) was the only independent predictive factor for CMPA persistence for group II.

CONCLUSION

The prognosis in cases of CMPA, a food allergy, is good, with tolerance developing over time. The presence of IgE-mediated CMPA, respiratory-related symptoms (ie, tachypnea), and the presence of comorbid food allergies have negative effects on tolerance.

Relevance of low specific IgE levels to egg, milk and peanut in infancy

BACKGROUND

IgE sensitization is usually associated with allergy-related diseases, but may also occur in asymptomatic individuals. The clinical importance of IgE antibody concentrations in the interval 0.1-0.34 kU/L in early life in relation to allergy development is poorly evaluated.

OBJECTIVE

To assess the relevance of low specific IgE (s-IgE) to hen's egg, cow's milk and peanut at 6 months of age for development of sensitization and allergy-related disease during early childhood.

METHODS

s-IgE concentrations to relevant allergens from blood samples taken at 6 months and 1, 2 and 5 years from children in the prospective ALADDIN cohort were divided into three categories: non-sensitized (<0.1 kU/L), low sensitized (0.1-0.34 kU/L) and sensitized (≥0.35 kU/L) and allergy-related disease assessed.

RESULTS

A total of 372 children were included in this study. Compared with non-sensitized children at 6 months of age, children with low levels of allergen specific IgE (0.1-0.34 kU/L) to food allergens, especially to egg, at 6 months of age were associated with development of sensitization to aeroallergens at 5 years of age (10/14 [71%] vs 39/250 [15%]). In addition, children with low levels to egg or milk at 6 months were more often sensitized to the respective allergen at 1 year of age and, regarding low levels to egg, also to the development of eczema (6/18 [33%] vs 29/292 [10%]).

CONCLUSION & CLINICAL RELEVANCE

IgE antibody concentrations in the interval 0.1-0.34 kU/L to food allergens in infancy seem to increase the probability of sensitization to aeroallergens and, regarding low levels to egg, also of eczema during early childhood. Thus, IgE levels during the first year of life, although below 0.35 kU/L, can provide additional allergy-related prognostic information.

Clinical and immunological profile of children aged 5-9 years with persistent egg allergy before oral immunotherapy with egg. A multicenter, randomized controlled trial of the Spanish Society of Pediatric Allergy, Asthma and Clinical Immunology (SEICAP)

BACKGROUND

In children with egg protein allergy (EA), the probability of overcoming the allergy decreases with age, and the possibility of suffering severe adverse reactions as a consequence of dietetic transgressions results in worsened quality of life. One treatment option in such cases is oral immunotherapy (OIT) with foods.

METHODS

We present a cohort of children with EA scheduled for OIT with pasteurized raw egg white, describing their clinical and allergic characteristics before the start of OIT.

RESULTS

The median age was six years, and 93% of the patients also suffered other allergies (58% asthma and 38.6% allergy to more than two food groups). In the last year, 14.8% had suffered a severe reaction due to dietetic transgression with egg. The median IgE specific of egg white titer was 38.5kU/l. A double-blind placebo-controlled food challenge with cooked egg white was performed, and if the test proved positive, it was repeated with pasteurized raw egg white. The mean symptoms-provoking dose was 1.26g and 0.55g for cooked egg white and raw egg white, respectively. An IgE specific of ovomucoid titer of <2.045kU/l differentiated those patients that tolerated cooked egg white.

CONCLUSIONS

OIT with egg is regarded as an option in patients with persistent egg allergy. In the previous challenge test, an IgE specific of ovomucoid titer of <2.045kU/l differentiates those patients that tolerate cooked egg white.

Polysaccharide isolated from Aloe vera gel suppresses ovalbumin-induced food allergy through inhibition of Th2 immunity in mice

An allergic reaction occurs when the immune system overreacts to harmless substance called allergen that gains access to the body. Food allergy is a hypersensitive immune reaction to food proteins and the number of patients with food allergy has recently increased. Aloe Vera is used for wellness and medicinal purposes. In particular, Aloe vera has been reported to enhance immunity. However, the effect of Aloe vera on food allergy is not yet known. In this study, we investigated the effects of processed Aloe vera gel (PAG) containing low molecular weight Aloe polysaccharide (AP) on ovalbumin (OVA)-induced food allergy in mice. Allergic symptoms, rectal temperature, and diarrhea were measured in OVA-induced food allergy mice. Other allergic parameters were also analyzed by RT-PCR, ELISA, flow cytometry, and other biochemical methods. As the results, PAG suppressed the decrease of body temperature, diarrhea, and allergic symptoms in OVA-induced food allergy mice. PAG also reduced serum concentrations of type 2 helper T cell (Th2) cytokines (Interleukin-(IL)-4, IL-5, and IL-13) as well as histamine, mast cell protease-1 (MCP-1), and immunoglobulin (Ig)E. PAG blocked the degranulation of mast cells and infiltration of eosinophils in intestine. Furthermore, PAG suppressed the population of Th2 cells in spleen and mesenteric lymph nodes. PAG also increased the production of IL-10 and population of type 1 regulatory T (Tr1) cells in mice with food allergy. Taken together, our findings suggest that PAG suppressed Th2 immune responses through, at least partially, stimulating the secretion of IL-10 in food allergy mice.

Making the Most of In Vitro Tests to Diagnose Food Allergy

Various in vitro tests assess different aspects of the underlying immune mechanism of IgE-mediated food allergy. Some can be used for diagnostic purposes; specific IgE to allergen extracts is widely available; specific IgE to allergen components is used in most specialist centers, and the basophil activation test is becoming increasingly used clinically. IgE to allergen peptides, T-cell assays, allergen-specific/total IgE ratios, and allergen-specific IgG4/IgE ratios are currently reserved for research. Different factors can modulate the likelihood of IgE-mediated food allergy of a given allergy test result, namely, the patients' age, ethnicity, previous allergic reaction to the identified food, concomitant atopic conditions, and geographical location, and need to be taken into account when interpreting the allergy test results in the clinic. The importance of the specific food, the clinical resources available, and patient preferences are additional aspects that need to be considered when deciding whether an oral food challenge is required to reach an accurate diagnosis of IgE-mediated food allergy.

Diagnosis of Food Allergy

Food allergy diagnosis remains challenging. Most standard methods are unable to differentiate sensitization from clinical allergy. Recognizing food allergy is of utmost importance to prevent life-threatening reactions. On the other hand, faulty interpretation of tests leads to overdiagnosis and unnecessary food avoidances. Highly predictive models have been established for major food allergens based on skin prick testing and food-specific immunoglobulin E but are lacking for most other foods. Although many newer diagnostic techniques are improving the accuracy of food allergy diagnostics, an oral food challenge remains the only definitive method of confirming a food allergy.

Relationship between specific IgE to egg components and natural history of egg allergy in Danish children

BACKGROUND

The majority of egg-allergic children develop tolerance over time. However, it may take numerous of consecutive egg challenges to get there as no good indices to predict tolerance exist.

OBJECTIVE

To investigate whether serial measurements of specific IgE to egg white, ovomucoid, ovalbumin, conalbumin, lysozyme, and egg yolk could improve the specificity of the diagnostic workup and aid in the decision when to rechallenge egg-allergic children.

METHODS

The outcome of oral food challenges with hen's egg and corresponding specific IgE levels were evaluated in children referred to The Allergy Center within an 8-year period. The egg-allergic children were rechallenged and had specific IgE levels measured once a year.

RESULTS

During a median follow-up of 26 months, 287 challenges and corresponding 287 serum analyses were performed in 130 children. Of the 130 children, 99 were egg allergic and 82 of these were rechallenged. Based on the initial diagnostic challenges only, area under the curve (AUC) estimates of the ability of specific IgE titers to distinguish between egg sensitization and egg allergy were only modest (maximum 0.83) and provided no clinical meaningful decision points. Specific IgE levels at baseline did not differ between tolerant and persistent allergic children. However longitudinally, acquisition of tolerance was associated with a decrease in IgE to egg white and to ovomucoid. In all cases of an increase in IgE to ovomucoid, the rechallenge was positive.

CONCLUSION

The decision when to rechallenge egg-allergic children should encounter the course of specific IgE.

A new framework for the interpretation of IgE sensitization tests

IgE sensitization tests, such as skin prick testing and serum-specific IgE, have been used to diagnose IgE-mediated clinical allergy for many years. Their prime drawback is that they detect sensitization which is only loosely related to clinical allergy. Many patients therefore require provocation tests to make a definitive diagnosis; these are often expensive and potentially associated with severe reactions. The likelihood of clinical allergy can be semi-quantified from an IgE sensitization test results. This relationship varies though according to the patients' age, ethnicity, nature of the putative allergic reaction and coexisting clinical diseases such as eczema. The likelihood of clinical allergy can be more precisely estimated from an IgE sensitization test result, by taking into account the patient's presenting features (pretest probability). The presence of each of these patient-specific factors may mean that a patient is more or less likely to have clinical allergy with a given test result (post-test probability). We present two approaches to include pretest probabilities in the interpretation of results. These approaches are currently limited by a lack of data to allow us to derive pretest probabilities for diverse setting, regions and allergens. Also, cofactors, such as exercise, may be necessary for exposure to an allergen to result in an allergic reaction in specific IgE-positive patients. The diagnosis of IgE-mediated allergy is now being aided by the introduction of allergen component testing which may identify clinically relevant sensitization. Other approaches are in development with basophil activation testing being closest to clinical application.

Cow's Milk Protein Allergy

Cow's milk protein allergy (CMPA) is a common condition encountered in children with incidence estimated as 2% to 7.5% in the first year of life. Formula and breast-fed babies can present with symptoms of CMPA. It is important to accurately diagnose CMPA to avoid the consequences of either under- or overdiagnosis. CMPA is classically categorized into immunoglobulin E (IgE)- or non-IgE-mediated reaction that vary in clinical manifestations, diagnostic evaluation, and prognosis. The most commonly involved systems in patients with CMPA are gastrointestinal, skin, and respiratory. Evaluation of CMPA starts with good data gathering followed by testing if indicated. Treatment is simply by avoidance of cow's milk protein (CMP) in the child's or mother's diet, if exclusively breast-feeding. This article reviews the definition, epidemiology, risk factors, pathogenesis, clinical presentation, evaluation, management, and prognosis of CMPA and provides an overview of different options for formulas and their indication in the treatment of CMPA.