Epidemiology of Food Allergy

The importance of the 2S albumins for allergenicity and cross-reactivity of peanuts, tree nuts, and sesame seeds

Allergies to peanuts, tree nuts, and sesame seeds are among the most important food-related causes of anaphylaxis. Important clinical questions include: Why is there a variable occurrence of coallergy among these foods and Is this immunologically mediated? The clinical and immunologic data summarized here suggest an immunologic basis for these coallergies that is based on similarities among the 2S albumins. Data from component resolved diagnostics have highlighted the relationship between IgE binding to these allergens and the presence of IgE-mediated food allergy. Furthermore, in vitro and in vivo experiments provide strong evidence that the 2S albumins are the most important allergens in peanuts for inducing an allergic effector response. Although the 2S albumins are diverse, they have a common disulfide-linked core with similar physicochemical properties that make them prime candidates to explain much of the observed coallergy among peanuts, tree nuts, and sesame seeds. The well-established frequency of cashew and pistachio nut coallergy (64%-100%) highlights how the structural similarities among their 2S albumins may account for observed clinical cross-reactivity. A complete understanding of the physicochemical properties of the 2S albumins in peanuts, tree nuts, and sesame seeds will enhance our ability to diagnose, treat, and ultimately prevent these allergies.

Health disparities in allergic and immunologic conditions in racial and ethnic underserved populations: A Work Group Report of the AAAAI Committee on the Underserved

Health disparities are health differences linked with economic, social, and environmental disadvantage. They adversely affect groups that have systematically experienced greater social or economic obstacles to health. Renewed efforts are needed to reduced health disparities in the United States, highlighted by the disparate impact on racial minorities during the coronavirus pandemic. Institutional or systemic patterns of racism are promoted and legitimated through accepted societal standards, and organizational processes within the field of medicine, and contribute to health disparities. Herein, we review current evidence regarding health disparities in allergic rhinitis, asthma, atopic dermatitis, food allergy, drug allergy, and primary immune deficiency disease in racial and ethnic underserved populations. Best practices to address these disparities involve addressing social determinants of health and adopting policies to improve access to specialty care and treatment for the underserved through telemedicine and community partnerships, cross-cultural provider training to reduce implicit bias, inclusion of underserved patients in research, implementation of culturally competent patient education, and recruitment and training of health care providers from underserved communities. Addressing health disparities requires a multilevel approach involving patients, health providers, local agencies, professional societies, and national governmental agencies.

Omalizumab as an adjuvant in food allergen immunotherapy

PURPOSE OF REVIEW

To review the most relevant studies in the rapidly advancing field of omalizumab as an adjunct to food allergen oral immunotherapy (OIT).

RECENT FINDINGS

Clinical trials have primarily focused on milk, peanut, and multiallergen OIT combined with omalizumab. These studies suggest that omalizumab in addition to OIT can decrease the time required to reach maintenance OIT dosing and adverse events; however, serious adverse events did still occur. There is limited long-term data but available information suggests that individuals are at risk for increased reactivity after stopping omalizumab, and many discontinued treatment. There has been diversity in study designs, dosing, and populations.

SUMMARY

The use of anti-IgE antibody as an adjunct to food allergen OIT has been an expanding area of research with several additional trials underway. Significant progress has been made in the past decades but further studies are needed to optimize protocols, improve safety and efficacy, and identify patients who will have the greatest benefit.

Insights into how innocuous foods or proteins deserving of immune ignorance can become allergens

Allergic disorders include food allergy, allergic rhinitis, and certain forms of asthma resulting from the inappropriate development of immune responses to otherwise innocuous aeroallergens and foods. In this issue of the JCI, Thouvenot and Roitel et al. explore transcription infidelity as a mechanism that underlies the ability of these benign proteins to become allergens. Some foods and bioaerosols that produce allergies have RNA polymerase with a propensity to generate RNA gaps, thereby causing translational frameshifts. These frameshifts often create cationic carboxy-terminus residues that replace hydrophobic amino acids and have enhanced MHC binding, resulting in the tendency to provoke immune responses. IgE antibody responses initiated by these variant transcripts can later lead to IgE against the native molecule and also explain how anaphylaxis may occur in individuals who lacked specific IgE when tested using native protein reagents. This study has the potential to transform the diagnosis and treatment of allergic disorders.

Hazelnut Allergy

Background and Objectives: Hazelnuts are frequently involved in IgE-mediated reactions and represent the main culprit of nut allergy in Europe. The clinical presentation varies from mild symptoms limited to the oropharynx [oral allergy syndrome (OAS)], due to the cross-reaction with homologues in pollen allergens and more severe events caused by the primary sensitization to highly stable molecules contained in hazelnuts. The aim of this review is to summarize the most relevant concepts in the field of hazelnut allergy and to provide a practical approach useful in the clinical practice Materials and Methods: References were identified by PubMed searches dating from January 2000 up to November 2020 using the search terms: “component resolved diagnosis” and “Hazelnut allergy. Results: The storage proteins Cor a 9 and Cor a 14 resulted highly specific for primary hazelnut allergy and strongly associated with severe reactions, while the cross reactive Cor a 1, an homolog of the birch Bet v1, were related to OAS. Any cut-off has shown a specificity and sensitivity pattern as high as to replace the oral food challenge (OFC), which still remains the gold standard in the diagnosis of hazelnut allergy. To date there is still no definitive treatment. Hazelnut free-diet and treatment of symptoms with emergency management, including the prescription of auto-injective epinephrine, still represent the main approach. Oral allergen immunotherapy (AIT) appears a promising therapeutic strategy and the definition of individual clinical threshold would be useful for sensitized individuals, caregivers, and physicians to reduce social limitation, anxiety, and better manage food allergy. Conclusions: An accurate diagnostic work-up including clinical history, in vivo and in vitro test including component resolved diagnosis and OFC are essential to confirm the diagnosis, to assess the risk of a severe reaction, and to prescribe an adequate diet and treatment.

T-Cell Epitope Immunotherapy in Mouse Models of Food Allergy

Food allergy has been rising in prevalence over the last two decades, affecting more than 10% of the world population. Current management of IgE-mediated food allergy relies on avoidance and rescue medications; research into treatments that are safer and providing guaranteed and durable curative effects is, therefore, essential. T-cell epitope-based immunotherapy holds the potential for modulating food allergic responses without IgE cross-linking. In this chapter, we describe the methods in evaluating the therapeutic capacities of immunodominant T-cell epitopes in animal models of food allergy. Moreover, we explain in detail the methods to measure the allergen-specific antibody levels, prepare single-cell suspension from spleen, and prepare small intestine for immunohistochemical analysis of eosinophils and Foxp3+ cells.

Validation of a MS Based Proteomics Method for Milk and Egg Quantification in Cookies at the Lowest VITAL Levels: An Alternative to the Use of Precautionary Labeling

The prevalence of food allergy has increased over the last decades and consequently the food labeling policies have improved over the time in different countries to regulate allergen presence in foods. In particular, Reg 1169 in EU mandates the labelling of 14 allergens whenever intentionally added to foods, but the inadvertent contamination by allergens still remains an uncovered topic. In order to warn consumers on the risk of cross-contamination occurring in certain categories of foods, a precautionary allergen labelling system has been put in place by food industries on a voluntary basis. In order to reduce the overuse of precautionary allergen labelling (PAL), reference doses and action limits have been proposed by the Voluntary Incidental Trace Allergen Labelling VITAL project representing a guide in this jeopardizing scenario. Development of sensitive and reliable mass spectrometry methods are therefore of paramount importance in this regard to check the contamination levels in foods. In this paper we describe the development of a time-managed multiple reaction monitoring (MRM) method based on a triple quadrupole platform for milk and egg quantification in processed food. The method was in house validated and allowed to achieve levels of proteins lower than 0.2 mg of total milk and egg proteins, respectively, in cookies, challenging the doses recommended by VITAL. The method was finally applied to cookies labeled as milk and egg-free. This method could represent, in perspective, a promising tool to be implemented along the food chain to detect even tiny amounts of allergens contaminating food commodities.

Transcriptional frameshifts contribute to protein allergenicity

Transcription infidelity (TI) is a mechanism that increases RNA and protein diversity. We found that single-base omissions (i.e., gaps) occurred at significantly higher rates in the RNA of highly allergenic legumes. Transcripts from peanut, soybean, sesame, and mite allergens contained a higher density of gaps than those of nonallergens. Allergen transcripts translate into proteins with a cationic carboxy terminus depleted in hydrophobic residues. In mice, recombinant TI variants of the peanut allergen Ara h 2, but not the canonical allergen itself, induced, without adjuvant, the production of anaphylactogenic specific IgE (sIgE), binding to linear epitopes on both canonical and TI segments of the TI variants. The removal of cationic proteins from bovine lactoserum markedly reduced its capacity to induce sIgE. In peanut-allergic children, the sIgE reactivity was directed toward both canonical and TI segments of Ara h 2 variants. We discovered 2 peanut allergens, which we believe to be previously unreported, because of their RNA-DNA divergence gap patterns and TI peptide amino acid composition. Finally, we showed that the sIgE of children with IgE-negative milk allergy targeted cationic proteins in lactoserum. We propose that it is not the canonical allergens, but their TI variants, that initiate sIgE isotype switching, while both canonical and TI variants elicit clinical allergic reactions.

Food allergy in at-risk adolescents with asthma: A key area for focus

BACKGROUND

Asthma affects more than 6.2 million children in the United States and is a major source of chronic disease burden. Concurrent food allergy (FA) may be a risk factor for worse asthma outcomes.

OBJECTIVE

To estimate the prevalence of FA among a cohort of adolescents with persistent asthma and assess whether FA is an independent risk factor for asthma morbidity.

METHODS

We included 342 adolescents aged 12 to 16 years with persistent asthma from the Rochester city school district who participated in the School-Based Asthma Care for Teens trial between 2014 and 2018. Multivariable models were used to estimate the association between FA and asthma morbidity.

RESULTS

Overall, 29% of adolescents with asthma reported having a FA. Although there were no statistically significant differences in daytime asthma symptoms, teens with FA had higher fractional exhaled nitric oxide (47.5 vs 33.9 P = .002) and reported more days with activity limitation owing to asthma (3.1 vs 2.3 days/2 weeks, P = .03) compared with teens without FA. Less than half (42%) of adolescents with FA had an epinephrine autoinjector.

CONCLUSION

This study found FA to be common among this cohort of adolescents with asthma. Although FA was not related to asthma symptom severity, adolescents with FA had higher fractional exhaled nitric oxide and more activity limitation, and most did not have epinephrine autoinjectors. A history of FA and lack of epinephrine autoinjector may increase near-fatal outcomes in adolescents with asthma. Preventive measures in addition to standard asthma treatments are warranted for these teens.

The Sesame-Peanut Conundrum in Israel: Reevaluation of Food Allergy Prevalence in Young Children

BACKGROUND

Food allergies (FAs) are on the rise worldwide. A previous cross-sectional study from 2002 in Israel estimated the prevalence of IgE-mediated FA among young children at 0.85%. Although sesame was found to be a common allergen, peanuts were found to be a rare allergen.

OBJECTIVE

To determine the prevalence and distributions of IgE-mediated FAs among young children in Israel compared with previous data.

METHODS

A total of 1932 young children (56% males, 44% females) with a mean age of 22.4 months (range, 18-30 months) were sequentially recruited from 15 government family health care centers in north Israel. Parents completed a questionnaire with 2 screening questions for suspected FA. Subjects with suspected FA underwent further evaluation including telephone interview, skin prick tests, and oral food challenge as needed.

RESULTS

After analyzing the questionnaires, 146 subjects were suspected to have FA. Seventy-nine subjects were excluded by telephone interview and 13 were excluded on the basis of negative oral food challenge. We identified 54 of 1932 (2.8%) young children with 75 IgE-mediated FAs. Thirty-nine of 54 (72.2%) had allergy to 1 food and 9 (16.6%) to 2 foods. The most common food allergens were cow's milk (1%), eggs (0.88%), sesame (0.93%), tree nuts (0.57%), peanuts (0.2%), and fish (0.2%).

CONCLUSIONS

The prevalence of IgE-mediated FA among young children in Israel has increased dramatically from 0.85% to 2.8%. The relative prevalence of the most common food allergens is similar to that identified in 2002, with a high prevalence of sesame FA and low prevalence of peanut FA.

Oral immunotherapy for treatment of peanut allergy

The US Food and Drug Administration's approval of a peanut oral immunotherapy product in January 2020 is a landmark development in the field of food allergy therapy. While food allergy prevalence has been increasing, this product is the first approved therapy for food allergy. Oral immunotherapy has many similarities to subcutaneous immunotherapy and drug desensitization protocols, but does not lead to sustained unresponsiveness. The studies leading to approval of the Palforzia product demonstrated increase in the amount of peanut protein able to be consumed, with 67% of subjects randomized to the treatment arm able to consume 600 mg of peanut protein in double-blind placebo-controlled food challenge at study exit. However, side effects are an important consideration, and dropout rates in studies of Palforzia ranged from 11% to 21%. Postmarketing surveillance of this product will be critical in assessing its long-term risks and benefits.

Allergenicity of Fermented Foods: Emphasis on Seeds Protein-Based Products

Food allergy is an IgE-mediated abnormal response to otherwise harmless food proteins, affecting between 5% and 10% of the world preschool children population and 1% to 5% adults. Several physical, chemical, and biotechnological approaches have been used to reduce the allergenicity of food allergens. Fermentation processes that contribute to technological and desirable changes in taste, flavor, digestibility, and texture of food products constitute one of these approaches. Lactic acid bacteria (LAB), used as starter cultures in dairy products, are a subject of increasing interest in fermentation of plant proteins. However, the studies designed to assess the impact of LAB on reduction of allergenicity of seed proteins are at an early stage. This review presents the current knowledge on food fermentation, with a focus on seed proteins that are increasingly used as ingredients, and its impacts on food potential allergenicity.

Design, quality, safety and efficacy of extensively hydrolyzed formula for management of cow's milk protein allergy: What are the challenges?

Cow's milk protein allergy (CMPA) is one of the most common food allergies in infancy. Clinical food allergy guidelines recommend an extensively hydrolyzed formula (EHF) as the first-line treatment in nonbreastfed infants with CMPA. Designing and commercializing EHF poses both technical and regulatory challenges. Each manufacturing step, from sourcing of raw materials to release of the final product, needs to be managed in accordance with comprehensive quality systems. To avoid cross-contamination via externally sourced ingredients, suppliers should be carefully selected based on quality requirements. Strict zoning of the manufacturing areas according to contamination risk and air flow control are effective strategies to prevent accidental allergen contamination. Furthermore, dedicated manufacturing lines for hypoallergenic products are used to prevent potential cross-contamination from other products produced on the same line. The enzymatic hydrolysis, heat treatment and ultrafiltration used are specific to each manufacturer. Consequently, EHF are a heterogenous group of products with differences in the molecular weight profile of peptides, content of residual immunogenic cow's milk allergens, and residual in-vitro allergenicity. These differences are likely to affect clinical efficacy and safety. As not all commercialized EHF products have undergone formal testing in the laboratory and clinical trials, there is a need to develop guidelines for minimum technical and regulatory requirements for EHF products, including validated assays for ongoing quality control. Clinical trials assessing new EHF products for their hypoallergenicity and ability to support normal growth remain the definitive proof of efficacy and safety in infants and young children with CMPA.

Self-Reported Prevalence of Allergies in the USA and Impact on Skin-An Epidemiological Study on a Representative Sample of American Adults

Background: The rising prevalence of allergies can substantially impact the skin, which is one of the largest targets for allergic and immunologic responses. Objective: Here, we describe the results of an online survey assessing self-reported allergy prevalence in Americans, outline the populations who report allergies, and characterize the skin conditions associated with allergy. Methods: An online survey was conducted in the USA of 2008 adults as a representative sample of the general American population. Results: 41.7% of American adults (mean age 44.7 ± 15.3 years old) reported having allergies. Reported allergies included respiratory allergies (45.2%), skin allergies (41.4) and food allergies (33.9%). 47.7% of those who reported allergies also reported experiencing associated skin reactions. In addition, those who reported allergies were 2 to 4.5 times more likely to report a cutaneous skin disease, 7 times more likely to report sensitive skin, and twice as likely to report experiencing skin reactions when using skincare products compared to those who did not report allergies. Conclusions: It is estimated that over 100 million American adults have allergies. These results will help raise awareness about the burden of allergies and the need to develop solutions to mitigate their impact on health.

Recent developments and advances in atopic dermatitis and food allergy

This review highlights recent advances in atopic dermatitis (AD) and food allergy (FA), particularly on molecular mechanisms and disease endotypes, recent developments in global strategies for the management of patients, pipeline for future treatments, primary and secondary prevention and psychosocial aspects. During the recent years, there has been major advances in personalized/precision medicine linked to better understanding of disease pathophysiology and precision treatment options of AD. A greater understanding of the molecular and cellular mechanisms of AD through substantial progress in epidemiology, genetics, skin immunology and psychological aspects resulted in advancements in the precision management of AD. However, the implementation of precision medicine in the management of AD still requires the validation of reliable biomarkers, which will provide more tailored management, starting from prevention strategies towards targeted therapies for more severe diseases. Cutaneous exposure to food via defective barriers is an important route of sensitization to food allergens. Studies on the role of the skin barrier genes demonstrated their association with the development of IgE-mediated FA, and suggest novel prevention and treatment strategies for type 2 diseases in general because of their link to barrier defects not only in AD and FA, but also in asthma, chronic rhinosinusitis, allergic rhinitis and inflammatory bowel disease. The development of more accurate diagnostic tools, biomarkers for early prediction, and innovative solutions require a better understanding of molecular mechanisms and the pathophysiology of FA. Based on these developments, this review provides an overview of novel developments and advances in AD and FA, which are reported particularly during the last two years.

New Perspectives in Food Allergy

The improvement of the knowledge of the pathophysiological mechanisms underlying the tolerance and sensitization to food antigens has recently led to a radical change in the clinical approach to food allergies. Epidemiological studies show a global increase in the prevalence of food allergy all over the world and manifestations of food allergy appear increasingly frequent also in elderly subjects. Environmental and nutritional changes have partly changed the epidemiology of allergic reactions to foods and new food allergic syndromes have emerged in recent years. The deepening of the study of the intestinal microbiota has highlighted important mechanisms of immunological adaptation of the mucosal immune system to food antigens, leading to a revolution in the concept of immunological tolerance. As a consequence, new prevention models and innovative therapeutic strategies aimed at a personalized approach to the patient affected by food allergy are emerging. This review focuses on these new perspectives and their practical implications in the management of food allergy, providing an updated view of this complex pathology.

Prevalence and Characteristics of Shellfish Allergy in the Pediatric Population of the United States

BACKGROUND

Shellfish allergy (SA) is one of the most common food allergies causing anaphylaxis in adults and children. There are limited data showing the prevalence of SA in US children.

OBJECTIVE

To determine the prevalence and reaction characteristics of SA in the US pediatric population.

METHODS

A cross-sectional food allergy prevalence survey was administered via phone and the Web by the National Opinion Research Center at the University of Chicago from 2015 to 2016. Point prevalence SA estimates, complex survey weighted proportions, and 95% CIs were determined. Relative proportions of demographic characteristics were compared using weighted Pearson χ² statistics.

RESULTS

The prevalence of SA was 1.3% (95% CI, 1.1-1.5), with more children allergic to crustaceans (1.2%; 95% CI, 1.0-1.3) than to mollusks (0.5%; 95% CI, 0.4-0.6). Mean ages of shellfish, crustacean, and mollusk allergy diagnoses were 5.0 (95% CI, 4.4-5.6), 5.1 (95% CI, 4.6-5.6), and 7.7 (95% CI, 5.7-9.7) years, respectively. More than half (54.9%; 95% CI, 48.1-61.4) of pediatric patients with SA had more than 1 lifetime food allergy-related emergency room visit, but only 45.7% (95% CI, 39.2-52.4) carried an epinephrine autoinjector. Children with SA were more likely to be black/Hispanic/Latino and have comorbid asthma, allergic rhinitis, or a parental history of asthma, environmental, or other food allergies (P < .001).

CONCLUSIONS

The epidemiology of SA in the US pediatric population shows that crustacean allergy is more common than mollusk allergy. A disparity in SA children and epinephrine autoinjector carriage exists. Results from this study will lead to increased awareness of the need for detailed histories, specific diagnostic tests, and rescue epinephrine for anaphylaxis in US children with SA.

The Evolving Microbiome from Pregnancy to Early Infancy: A Comprehensive Review

Pregnancy induces a number of immunological, hormonal, and metabolic changes that are necessary for the mother to adapt her body to this new physiological situation. The microbiome of the mother, the placenta and the fetus influence the fetus growth and undoubtedly plays a major role in the adequate development of the newborn infant. Hence, the microbiome modulates the inflammatory mechanisms related to physiological and pathological processes that are involved in the perinatal progress through different mechanisms. The present review summarizes the actual knowledge related to physiological changes in the microbiota occurring in the mother, the fetus, and the child, both during neonatal period and beyond. In addition, we approach some specific pathological situations during the perinatal periods, as well as the influence of the type of delivery and feeding.

Whole-Cell Pertussis Vaccination and Decreased Risk of IgE-Mediated Food Allergy: A Nested Case-Control Study

BACKGROUND

Rates of food allergy have increased markedly in Australia and other high- income countries in recent years. On the basis of ecological observations, and the known immunologic characteristics of whole-cell pertussis (wP) compared with acellular pertussis (aP) vaccines, we hypothesized that wP vaccination in infancy protects against the development of food allergy.

OBJECTIVE

To determine whether infants who receive wP in infancy were less likely to develop IgE-mediated food allergy than those who received aP.

METHODS

Retrospective cohort-nested case-control study of Australian children born in the period 1997 to 1999, the period of transition from using wP-containing to aP-containing vaccines. Children diagnosed with IgE-mediated food allergy were individually matched to 10 controls by date of birth, socioeconomic decile, and jurisdiction of birth. The odds ratio of vaccination with wP versus aP among cases and matched controls was calculated using conditional logistic regression.

RESULTS

The odds ratio of receiving the first dose as wP (rather than aP) among cases of food allergy compared with controls was 0.77 (95% CI, 0.62-0.95). The results of secondary analyses (any dose as wP vs aP-only, and wP-only vs aP-only) were broadly similar.

CONCLUSIONS

Australian infants who received wP vaccines were less likely to be diagnosed with food allergy in childhood than contemporaneous children who received aP vaccines. If a protective effect is confirmed in a randomized controlled trial, wP or mixed wP and aP vaccination schedules could form part of an effective strategy for combating the rise in food allergies.

IgE binding to linear epitopes of Ara h 2 in peanut allergic preschool children undergoing oral Immunotherapy

BACKGROUND

For patients with peanut allergy, there are currently no methods to predict who will develop sustained unresponsiveness (SU) after oral immunotherapy (OIT).

OBJECTIVE

Assess IgE binding to peanut (PN), Ara h 2, and specific linear epitopes of Ara h 2 as predictors of the important clinical parameters: eliciting dose threshold and attainment of SU following OIT.

METHODS

Samples and clinical data were collected from children undergoing OIT. PN- and Ara h 2-sIgE were quantified by ImmunoCAP^® . IgE binding to linear peptides of Ara h 2 and Ara h 6 was measured with peptide microarrays.

RESULTS

Values of PN-sIgE correlated with eliciting dose (P = .001) and with a higher likelihood of achieving SU (P < .0001), but these relationships were lost at higher values for PN-sIgE (≥14 kIU for eliciting dose and ≥35 kIU/L for SU). In subjects with PN-sIgE ≥ 14 kIU/L, binding of IgE to epitopes 5 and 6 of Ara h 2 was associated with a lower eliciting dose at baseline challenge (P < .001; P_c  < .02). In subjects with PN-sIgE ≥ 35 kIU/L, a combined model of IgE binding to epitopes 1, 5 and 6 with PN-sIgE was highly predictive of attainment of SU (AUC of 0.86; P = .0067).

CONCLUSION

In young patients with peanut allergy, measurement of PN-sIgE and IgE binding to specific linear epitopes of Ara h 2 in baseline samples may allow stratification of patients regarding sensitivity to challenge and outcome of OIT.

Fish Allergy Management: From Component-Resolved Diagnosis to Unmet Diagnostic Needs

Purpose of review

Fish is a common elicitor of IgE-mediated food allergy. Fish includes a large variety of foods, in terms of species and food processing, with marked distinction in local diets around the globe. Fish-allergic patients present with phenotypic diversity and major differences in levels of clinical cross-reactivity, features that pose an important challenge for the clinical diagnosis and management.

Recent findings

Parvalbumin is the major fish allergen. However, a single molecule is not sufficient but several homologs, allergens different from parvalbumin and allergen extracts, are needed for IgE-based diagnosis.

Summary

Parvalbumin-specific IgE are markers for clinical cross-reactions. Added value is provided by IgE typing to parvalbumin homologs from distantly related fish. IgE co-sensitization profiles (parvalbumin, enolase, aldolase) are referred as severity markers. The allergen panel seems to be not yet complete why fish extracts still play a crucial role in serum IgE analysis. Further clinical validation of a multiplex approach in molecular fish allergy diagnosis is needed for striving to avoid unnecessary food restrictions and in a further sense, improved patient care.

Allergen immunotherapy as add-on to biologic agents

PURPOSE OF REVIEW

In this review, we sought to outline many of the recent evidences about the available clinical trials in which biologic agents [i.e. omalizumab (OMA)] were associated as add-on to allergen-specific immunotherapy (AIT).

RECENT FINDINGS

The available literature shows that OMA may be a valuable option as add-on to AIT for respiratory allergy, or food desensitization, especially in the escalation or build-up phases, in which adverse events are more commonly expected. The encouraging data for hymenoptera venom allergy remain limited to case reports, and no structured clinical trial is available.

SUMMARY

Over the past decade, studies of OMA used with AIT have shown promising results. Today, big randomized, double-blind, placebo-controlled trials are needed to better select those patients who would benefit from the addition of OMA (or other biologic agents) to AIT, as well as optimal dosing schedules, optimal duration of treatments and, finally, adequate evaluation about pharmacoeconomic aspects.

Epidemiology of Cow's Milk Allergy

Immunoglobulin E (IgE)-mediated cow's milk allergy (CMA) is one of the most common food allergies in infants and young children. CMA can result in anaphylactic reactions, and has long term implications on growth and nutrition. There are several studies in diverse populations assessing the epidemiology of CMA. However, assessment is complicated by the presence of other immune-mediated reactions to cow's milk. These include non-IgE and mixed (IgE and non-IgE) reactions and common non-immune mediated reactions, such as lactose intolerance. Estimates of prevalence and population-level patterns are further complicated by the natural history of CMA (given its relatively high rate of resolution) and variation in phenotype (with a large proportion of patients able to tolerate baked cow's milk). Prevalence, natural history, demographic patterns, and long-term outcomes of CMA have been explored in several disparate populations over the past 30 to 40 years, with differences seen based on the method of outcome assessment, study population, time period, and geographic region. The primary aim of this review is to describe the epidemiology of CMA. The review also briefly discusses topics related to prevalence studies and specific implications of CMA, including severity, natural course, nutritional impact, and risk factors.

Prevalence of food allergy among schoolchildren in Kuwait and its association with the coexistence and severity of asthma, rhinitis, and eczema: A cross-sectional study

Background

Food allergy (FA) is a common public health problem that affects both children and adults. Empirical knowledge of the burden of FA in Kuwait is limited. This study sought to estimate the prevalence of FA among schoolchildren in Kuwait and assess associations between FA and the coexistence and severity of asthma, rhinitis, and eczema.

Methods

Schoolchildren aged 11–14 years (n = 3,864) were enrolled in a cross-sectional study. Parents completed questionnaires regarding their children's early life exposures and clinical history of FA and allergic diseases. Study-defined FA was ascertained by a convincing clinical history. Associations were assessed using Poisson regression with robust variance estimation, and adjusted prevalence ratios (aPRs) and 95% confidence intervals (CIs) were estimated.

Results

The 12-month prevalence of study-defined FA was estimated to be 4.1% (154/3,738), with more girls being affected than boys (aPR = 1.44, 95% CI: 1.04–1.99). Egg (2.7%), fish (1.6%), shellfish (1.3%), peanut (1.3%), and tree nut (1.2%) were the most reported offending food allergens. Underweight and adiposity, cesarean section delivery, exposure to household dogs during infancy, and parental history of doctor-diagnosed FA were associated with an increased prevalence of study-defined FA. However, later birth order was associated with a reduced prevalence of study-defined FA. The prevalence of eczema only was higher in children with study-defined FA than in those without study-defined FA (aPR = 3.49, 95% CI: 2.37–5.14). In contrast, this association was not pronounced for children who had asthma only (aPR = 1.56, 95% CI: 0.94–2.57) or rhinitis only (aPR = 1.40, 95% CI: 0.86–2.28). Study-defined FA was associated with a 9.20-fold (95% CI: 4.50–18.78) higher prevalence of coexisting asthma, rhinitis, and eczema. Moreover, study-defined FA was associated with increased severity of symptoms of asthma, rhinitis, and eczema.

Conclusions

FA affects a considerable proportion of schoolchildren in Kuwait, and the most reported offending food allergens are similar to those reported in Western countries. Study-defined FA was associated with the coexistence and increased severity of asthma, rhinitis, and eczema, indicating that FA may link the comanifestations of allergic diseases and contribute to their chronicity and severity.

The role of incurred materials in method development and validation to account for food processing effects in food allergen analysis

The issue of undeclared allergens represents a matter of great concern, being the subject of many alert notifications by the Rapid Alert System for Food and Feed portal of the European Commission, often leading to food recalls. The availability of reliable analytical approaches able to detect and quantify hidden allergens in processed foods is increasingly requested by the food industry, food safety authorities and regulatory bodies to protect sensitive consumers' health. The present review discusses the fundamental role of incurred materials for method development and analytical performance assessment in a metrology perspective on testing for undeclared allergens in processed foodstuffs. Due to the nature of the analytes and their susceptibility to various processing effects, reliability and comparability of results have posed a great challenge. In this context, the use of incurred samples as reference materials permits simulation of the effects of food processing on target analyte structure affecting analyte extractability and detectability. Graphical abstract ᅟ.

Prevalence and Severity of Food Allergies Among US Adults

IMPORTANCE

Food allergy is a costly, potentially life-threatening condition. Although studies have examined the prevalence of childhood food allergy, little is known about prevalence, severity, or health care utilization related to food allergies among US adults.

OBJECTIVE

To provide nationally representative estimates of the distribution, severity, and factors associated with adult food allergies.

DESIGN, SETTING, AND PARTICIPANTS

In this cross-sectional survey study of US adults, surveys were administered via the internet and telephone from October 9, 2015, to September 18, 2016. Participants were first recruited from NORC at the University of Chicago's probability-based AmeriSpeak panel, and additional participants were recruited from the non-probability-based Survey Sampling International (SSI) panel.

EXPOSURES

Demographic and allergic participant characteristics.

MAIN OUTCOMES AND MEASURES

Self-reported food allergies were the main outcome and were considered convincing if reported symptoms to specific allergens were consistent with IgE-mediated reactions. Diagnosis history to specific allergens and food allergy-related health care use were also primary outcomes. Estimates were based on this nationally representative sample using small-area estimation and iterative proportional fitting methods. To increase precision, AmeriSpeak data were augmented by calibration-weighted, non-probability-based responses from SSI.

RESULTS

Surveys were completed by 40 443 adults (mean [SD] age, 46.6 [20.2] years), with a survey completion rate of 51.2% observed among AmeriSpeak panelists (n = 7210) and 5.5% among SSI panelists (n = 33 233). Estimated convincing food allergy prevalence among US adults was 10.8% (95% CI, 10.4%-11.1%), although 19.0% (95% CI, 18.5%-19.5%) of adults self-reported a food allergy. The most common allergies were shellfish (2.9%; 95% CI, 2.7%-3.1%), milk (1.9%; 95% CI, 1.8%-2.1%), peanut (1.8%; 95% CI, 1.7%-1.9%), tree nut (1.2%; 95% CI, 1.1%-1.3%), and fin fish (0.9%; 95% CI, 0.8%-1.0%). Among food-allergic adults, 51.1% (95% CI, 49.3%-52.9%) experienced a severe food allergy reaction, 45.3% (95% CI, 43.6%-47.1%) were allergic to multiple foods, and 48.0% (95% CI, 46.2%-49.7%) developed food allergies as an adult. Regarding health care utilization, 24.0% (95% CI, 22.6%-25.4%) reported a current epinephrine prescription, and 38.3% (95% CI, 36.7%-40.0%) reported at least 1 food allergy-related lifetime emergency department visit.

CONCLUSIONS AND RELEVANCE

These data suggest that at least 10.8% (>26 million) of US adults are food allergic, whereas nearly 19% of adults believe that they have a food allergy. Consequently, these findings suggest that it is crucial that adults with suspected food allergy receive appropriate confirmatory testing and counseling to ensure food is not unnecessarily avoided and quality of life is not unduly impaired.

Racial differences in atopic dermatitis

OBJECTIVE

To summarize studies investigating ethnical and racial differences in atopic dermatitis (AD) epidemiology, clinical features, and skin and blood phenotypes.

DATA SOURCES

PubMed literature review (years 2000-2018).

STUDY SELECTIONS

Articles discussing primarily human disease.

RESULTS

Higher overall rates of AD were found in Africa and Oceania as opposed to India and Northern and Eastern Europe. In the United States, AD prevalence was found to be higher in African American (19.3%) compared with European American (16.1%) children. Although several studies have consistently found FLG loss-of-function mutations in up to 50% of European and 27% of Asian patients with AD, FLG mutations were 6 times less common in African American than in European American patients, even in patients with severe AD. Thus, FLG mutations seem to play less a pathogenic role in patients of African origin than in individuals of European or Asian ancestry. The immune phenotype of all ethnic groups was characterized by strong T_H2 activation, but important differences in immune polarization exist among the different ethnicities. Asian patients with AD had stronger T_H17/T_H22 activation than African American and European American patients with AD, whereas African American patients had the highest serum IgE levels among all groups, while largely lacking T_H1 and T_H17 activation.

CONCLUSION

AD is a heterogeneous disease that has differences among various ethnic and racial groups, which might be important for the development of future, targeted treatments and for personalized medicine approaches.

Soy extract and maltodextrin as microencapsulating agents for Lactobacillus acidophilus: a model approach

The present study aimed to optimise the microencapsulation of Lactobacillus acidophilus La-05 by spray drying, using soy extract and maltodextrin as encapsulants. Air inlet temperature, maltodextrin/soy extract ratio and feed flow rate were investigated through Central Composite Rotational Design (CCRD). Probiotic viability increased with increasing the proportion of soy extract. Temperature and feed flow rate had a negative effect. Particle diameter ranged from 4.97 to 8.82 μm, water activity from 0.25 to 0.52 and moisture from 2.30 to 7.01 g.100g-1 Particles produced following the optimised conditions (air temperature of 87 °C, maltodextrin/soy extract ratio of 2:3 w.w-1, feed flow rate of 0.54 L.h-1) reached Encapsulation yield (EY) of 83%. Thermogravimetry and FTIR analysis suggested that microcapsules could protect L. acidophilus cells against dehydration and heating. During storage, microencapsulated probiotic had high cell viability (reductions ranged between 0.12 and 1.72 log cycles). Soy extract/maltodextrin presented well-encapsulating properties of Lactobacillus acidophilus La-05.

Epigenetic Regulation via Altered Histone Acetylation Results in Suppression of Mast Cell Function and Mast Cell-Mediated Food Allergic Responses

Mast cells are highly versatile cells that perform a variety of functions depending on the immune trigger, context of activation, and cytokine stimulus. Antigen-mediated mast cell responses are regulated by transcriptional processes that result in the induction of numerous genes contributing to mast cell function. Recently, we also showed that exposure to dietary agents with known epigenetic actions such as curcumin can suppress mast cell-mediated food allergy, suggesting that mast cell responses in vivo may be epigenetically regulated. To further assess the effects of epigenetic modifications on mast cell function, we examined the behavior of bone marrow-derived mast cells (BMMCs) in response to trichostatin A (TSA) treatment, a well-studied histone deacetylase inhibitor. IgE-mediated BMMC activation resulted in enhanced expression and secretion of IL-4, IL-6, TNF-α, and IL-13. In contrast, pretreatment with TSA resulted in altered cytokine secretion. This was accompanied by decreased expression of FcεRI and mast cell degranulation. Interestingly, exposure to non-IgE stimuli such as IL-33, was also affected by TSA treatment. Furthermore, continuous TSA exposure contributed to mast cell apoptosis and a decrease in survival. Further examination revealed an increase in I-κBα and a decrease in phospho-relA levels in TSA-treated BMMCs, suggesting that TSA alters transcriptional processes, resulting in enhancement of I-κBα transcription and decreased NF-κB activation. Lastly, treatment of wild-type mice with TSA in a model of ovalbumin-induced food allergy resulted in a significant attenuation in the development of food allergy symptoms including decreases in allergic diarrhea and mast cell activation. These data therefore suggest that the epigenetic regulation of mast cell activation during immune responses may occur via altered histone acetylation, and that exposure to dietary substances may induce epigenetic modifications that modulate mast cell function.

Regulatory Immune Mechanisms in Tolerance to Food Allergy

Oral tolerance can develop after frequent exposure to food allergens. Upon ingestion, food is digested into small protein fragments in the gastrointestinal tract. Small food particles are later absorbed into the human body. Interestingly, some of these ingested food proteins can cause allergic immune responses, which can lead to food allergy. So far it has not been completely elucidated how these proteins become immunogenic and cause food allergies. In contrast, oral tolerance helps to prevent the pathologic reactions against different types of food antigens from animal or plant origin. Tolerance to food is mainly acquired by dendritic cells, epithelial cells in the gut, and the gut microbiome. A subset of CD103⁺ DCs is capable of inducing T regulatory cells (Treg cells) that express anti-inflammatory cytokines. Anergic T cells also contribute to oral tolerance, by reducing the number of effector cells. Similar to Treg cells, B regulatory cells (Breg cells) suppress effector T cells and contribute to the immune tolerance to food allergens. Furthermore, the human microbiome is an essential mediator in the induction of oral tolerance or food allergy. In this review, we outline the current understanding of regulatory immune mechanisms in oral tolerance. The biological changes reflecting early consequences of immune stimulation with food allergens should provide useful information for the development of novel therapeutic treatments.