Food allergy: epidemiology, pathogenesis, diagnosis, prevention, and treatment

The Lived Experiences of Students With Food Allergies During a Usual Weekday

BACKGROUND

Extant literature indicates students living with food allergies (FA) experience biopsychosocial challenges (eg, social isolation, anxiety). The purpose of this study was to explore the experiences of students living with FA during a usual weekday in a school setting.

METHODS

Phenomenological study with purposive convenience sample from the US states of Florida and Colorado. Students aged 10-14 years who have been managing an IgE-mediated FA for more than 1 year within a school setting. Data collection was guided by a story path process with semi-structured interview, with Interpretive Phenomenological Analysis used to ascribe meaning to their experiences.

RESULTS

Four themes: (1) Living with Restraints: A Way of Life, (2) Managing Exposure, (3) Experiencing Stigma, and (4) Experiencing Lack of Knowledge.

CONCLUSION

Findings underscore unique biopsychosocial challenges faced by students living with FA, highlighting the need for comprehensive approaches beyond traditional biological management in developing strategies, policies, future research, and recommendations in school settings.

IL-10 Neutralization Attenuates Mast Cell Responses in a Murine Model of Experimental Food Allergy

IgE-mediated mast cell (MC) activation is a critical component of allergic responses to oral Ags. Several T cell-derived cytokines have been shown to promote MC reactivity, and we recently demonstrated a critical role for the cytokine IL-10 in mediating MC responses during food allergy. In this study, we further validate the role of IL-10 using Ab-mediated IL-10 depletion. IL-10 neutralization significantly attenuated MC responses, leading to decreased MC accumulation and activation, as well as inhibition of MC-mediated symptoms such as allergic diarrhea. This was accompanied by decreased Th2 cytokine gene expression, attenuated systemic T cell responses, and fewer CD4 T cells, B cells, and MCs in the spleen. Our data further confirm the role of IL-10 in driving MC responses and suggest that IL-10-responsive MCs may constitute an important player in allergic responses.

IL-10 Differentially Promotes Mast Cell Responsiveness to IL-33, Resulting in Enhancement of Type 2 Inflammation and Suppression of Neutrophilia

Mast cells (MCs) play critical roles in the establishment of allergic diseases. We recently demonstrated an unexpected, proinflammatory role for IL-10 in regulating MC responses. IL-10 enhanced MC activation and promoted IgE-dependent responses during food allergy. However, whether these effects extend to IgE-independent stimuli is not clear. In this article, we demonstrate that IL-10 plays a critical role in driving IL-33-mediated MC responses. IL-10 stimulation enhanced MC expansion and degranulation, ST2 expression, IL-13 production, and phospho-relA upregulation in IL-33-treated cells while suppressing TNF-α. These effects were partly dependent on endogenous IL-10 and further amplified in MCs coactivated with both IL-33 and IgE/Ag. IL-10's divergent effects also extended in vivo. In a MC-dependent model of IL-33-induced neutrophilia, IL-10 treatment enhanced MC responsiveness, leading to suppression of neutrophils and decreased TNF-α. In contrast, during IL-33-induced type 2 inflammation, IL-10 priming exacerbated MC activity, resulting in MC recruitment to various tissues, enhanced ST2 expression, induction of hypothermia, recruitment of eosinophils, and increased MCPT-1 and IL-13 levels. Our data elucidate an important role for IL-10 as an augmenter of IL-33-mediated MC responses, with implications during both allergic diseases and other MC-dependent disorders. IL-10 induction is routinely used as a prognostic marker of disease improvement. Our data suggest instead that IL-10 can enhance ST2 responsiveness in IL-33-activated MCs, with the potential to both aggravate or suppress disease severity depending on the inflammatory context.

Facile and Ultrasensitive Food Allergen Quantification Using Microzone Paper-Based Mass Spectrometric Immunoassay

Highly sensitive and rapid measurement of food allergens is essential to avoid unanticipated food allergies and to determine whether cross-contamination occurs in the food industry. Commercial immunoassay kits offer high specificity and convenience for allergen detection but still suffer limited quantitative sensitivity, accuracy, and stability based on the optical readout. In this work, a paper-based mass spectrometric immunoassay platform was constructed to achieve facile and highly sensitive quantification of peanut allergen, which combined the advantages of good specificity and accurate quantification from mass spectrometry and simplicity from a paper-based immunoassay. In this platform, a novel quaternary ammonium-based mass tag and a paper chip with a microzone were designed and developed, contributing to a large signal enhancement. This method was able to detect Ara h1 with a linear range of 0.1-100 ng mL-1 and a detection limit of 0.08 ng mL-1 in milk matrices. It has also been successfully applied to the accurate quantification of Ara h1 in six milk-related beverages, two biscuits, and two candy bars with complicated matrices and presented a low-concentration quantitation capability. This method gives a new type of mass spectrometric immunoassay for rapid and ultrasensitive allergen regulation in the food industry and for individual allergen differentiation research.

Current and Future Treatment of Food Allergies

Food allergy prevalence is rapidly growing among school-age children in the United States, posing a significant health concern in school settings. This article aims to provide an overview of the current state of food allergy treatment options, emergency food allergy care plans, and using epinephrine autoinjectors. In addition, it explores potential future treatment options, including immunotherapy and novel therapeutic approaches. This article emphasizes the crucial role of school nurses in recognizing the treatment options currently available to students and their families, as well as fostering a safe environment for students with food allergies.

Evaluation of vitamin B12 values at time of diagnosis in 0- to 36-month-old children with food allergies

OBJECTIVES

The relationship between food allergies and vitamin B12 deficiency in young children remains unclear despite extensive studies on the nutritional status of affected children. The aim of this study was to compare vitamin B12 levels in children with recently diagnosed food allergies and healthy children ages 0 to 36 mo.

METHODS

A retrospective study at Başkent University Hospital analyzed 773 patients ages 0 to 36 mo. Participants were divided into two groups: food allergy and healthy. Vitamin B12 deficiency (<300 ng/mL) was assessed using χ2 tests and regression analyses.

RESULTS

The sample comprised 773 children ages 0 to 36 mo, with a mean age of 16 ± 9 mo (range: 1-36). Among the participants, 399 (52%) were healthy children, whereas 374 (48%) had food allergies. The prevalence of vitamin B12 deficiency was higher in children with food allergies (38%) than in healthy children (21%; P < 0.001). According to both univariate and multivariate regression analyses, formula feeding showed a negative association with vitamin B12 deficiency (β = -0.54; 95% confidence interval [CI], 0.35-0.97; P = 0.038). On the other hand, having allergic diseases (β = 0.69; 95% CI, 0.30-0.83; P = 0.040) and breastfeeding for <6 mo (β = 1.35; 95% CI, 1.41-10.50-0.50; P = 0.009) exhibited a positive association with vitamin B12 deficiency.

CONCLUSION

Food-allergic children ages 0 to 36 mo were at higher risk for vitamin B12 deficiency. Formula feeding had a protective effect, whereas allergic diseases and breastfeeding for <6 mo were risk factors. Further investigation is needed to understand the underlying mechanisms. Monitoring B12 levels and interventions are crucial for the nutritional well-being of food-allergic children.

Alterations in the gut microbiota of toddlers with cow milk protein allergy treated with a partially hydrolyzed formula containing synbiotics: A nonrandomized controlled interventional study

Formulas containing intact cow milk protein are appropriate alternatives when human milk (HM) is not feasible. However, for babies with a physician-diagnosed cow milk protein allergy (CMPA), hydrolyzed formulas are needed. We conducted a 3-month, open-label, nonrandomized concurrent controlled trial (ChiCTR2100046909) between June 2021 and October 2022 in Qingdao City, China. In this study, CMPA toddlers were fed with a partially hydrolyzed formula containing synbiotics (pHF, n = 43) and compared with healthy toddlers fed a regular intact protein formula (IF, n = 45) or HM (n = 21). The primary endpoint was weight gain; the secondary endpoints were changes in body length and head circumference of both CMPA and healthy toddlers after 3-month feeding; and the exploratory outcomes were changes in gut microbiota composition. After 3 months, there were no significant group differences for length-for-age, weight-for-age, or head circumference-for-age Z scores. In the gut microbiota, pHF feeding increased its richness and diversity, similar to those of IF-fed and HM-fed healthy toddlers. Compared with healthy toddlers, the toddlers with CMPA showed an increased abundance of phylum Bacteroidota, Firmicutes, class Clostridia, and Bacteroidia, and a decreased abundance of class Negativicutes, while pHF feeding partly eliminated these original differences. Moreover, pHF feeding increased the abundance of short-chain fatty acid producers. Our data suggested that this pHF partly simulated the beneficial effects of HM and shifted the gut microbiota of toddlers with CMPA toward that of healthy individuals. In conclusion, this synbiotic-containing pHF might be an appropriate alternative for toddlers with CMPA.

Directed acyclic graph for epidemiological studies in childhood food allergy: Construction, user's guide, and application

Understanding modifiable prenatal and early life causal determinants of food allergy is important for the prevention of the disease. Randomized clinical trials studying environmental and dietary determinants of food allergy may not always be feasible. Identifying risk/protective factors for early-life food allergy often relies on observational studies, which may be affected by confounding bias. The directed acyclic graph (DAG) is a causal diagram useful to guide causal inference from observational epidemiological research. To date, research on food allergy has made little use of this promising method. We performed a literature review of existing evidence with a systematic search, synthesized 32 known risk/protective factors, and constructed a comprehensive DAG for early-life food allergy development. We present an easy-to-use online tool for researchers to re-construct, amend, and modify the DAG along with a user's guide to minimize confounding bias. We estimated that adjustment strategies in 57% of previous observational studies on modifiable factors of childhood food allergy could be improved if the researchers determined their adjustment sets by DAG. Future researchers who are interested in the causal inference of food allergy development in early life can apply the DAG to identify covariates that should and should not be controlled in observational studies.

Dietary Inflammatory Potential in Pediatric Diseases: A Narrative Review

Inflammatory status is one of the main drivers in the development of non-communicable diseases (NCDs). Specific unhealthy dietary patterns and the growing consumption of ultra-processed foods (UPFs) may influence the inflammation process, which negatively modulates the gut microbiota and increases the risk of NCDs. Moreover, several chronic health conditions require special long-term dietary treatment, characterized by altered ratios of the intake of nutrients or by the consumption of disease-specific foods. In this narrative review, we aimed to collect the latest evidence on the pro-inflammatory potential of dietary patterns, foods, and nutrients in children affected by multifactorial diseases but also on the dietetic approaches used as treatment for specific diseases. Considering multifactorial diet-related diseases, the triggering effect of pro-inflammatory diets has been addressed for metabolic syndrome and inflammatory bowel diseases, and the latter for adults only. Future research is required on multiple sclerosis, type 1 diabetes, and pediatric cancer, in which the role of inflammation is emerging. For diseases requiring special diets, the role of single or multiple foods, possibly associated with inflammation, was assessed, but more studies are needed. The evidence collected highlighted the need for health professionals to consider the entire dietary pattern, providing balanced and healthy diets not only to permit the metabolic control of the disease itself, but also to prevent the development of NCDs in adolescence and adulthood. Personalized nutritional approaches, in close collaboration between the hospital, country, and families, must always be promoted together with the development of new methods for the assessment of pro-inflammatory dietary habits in pediatric age and the implementation of telemedicine.

The origins and longevity of IgE responses as indicated by serological and cellular studies in mice and humans

The existence of long-lived IgE antibody-secreting cells (ASC) is contentious, with the maintenance of sensitization by the continuous differentiation of short-lived IgE+ ASC a possibility. Here, we review the epidemiological profile of IgE production, and give an overview of recent discoveries made on the mechanisms regulating IgE production from mouse models. Together, these data suggest that for most individuals, in most IgE-associated diseases, IgE+ ASC are largely short-lived cells. A subpopulation of IgE+ ASC in humans is likely to survive for tens of months, although due to autonomous IgE B cell receptor (BCR) signaling and antigen-driven IgE+ ASC apoptosis, in general IgE+ ASC probably do not persist for the decades that other ASC are inferred to do. We also report on recently identified memory B cell transcriptional subtypes that are the likely source of IgE in ongoing responses, highlighting the probable importance of IL-4Rα in their regulation. We suggest the field should look at dupilumab and other drugs that prohibit IgE+ ASC production as being effective treatments for IgE-mediated aspects of disease in most individuals.

Tackling food allergens-The role of food processing on proteins' allergenicity

This chapter examines how innovative and emerging food processing technologies, such as those that use heat, electricity, electromagnetic waves, and pressure, can modify protein denaturation, aggregation, and intermolecular interactions pathways, which can result in varying immunoreactive responses. It emphasizes the need to understand how these processing methods affect the protein epitopes recognized by antibodies and their respective priming pathways, especially during the sensitization stage that precedes an allergic response. Although traditional processing methods have been investigated, the impact of novel technologies on food protein allergenicity remains largely unknown. The chapter specifically focuses on milk proteins, which have clinical significance and are associated with cow's milk allergy, one of the most common food allergies in young children. Additionally, it examines potential scientific advancements that novel processing methods may bring to this field.

Influence of Lifestyle and Dietary Habits on the Prevalence of Food Allergies: A Scoping Review

Changes in behavior, lifestyle, and nutritional patterns have influenced many potential risk variables globally. In recent decades, food allergies (FAs) have been elevated to a severe public health issue both in developed countries and developing countries (third-world countries). This study aims to evaluate the effects caused by certain factors such as lifestyle and dietary habits on food allergies, review the association of lifestyle and dietary habit status with FAs, and outline why more people are allergic to food sources as a result of lifestyle changes and dietary habits. We searched electronic international databases including Scopus, PubMed, Google Scholar, and Web of Science using combinations of keywords. Utilizing Excel, the relevant studies were included and the irrelevant studies were excluded, and Mendeley was used for referencing and also to remove duplicates. The framework proposed by Arksey and O'Malley was used for this scoping review. The papers published in the databases from 2016 to 2020 were extracted. A total of eight studies were extracted, and this scoping review was carried out according to the risk factors. In our review, we found that some lifestyle choices (Caesarean section and antibiotics) and dietary habits (n-3 PUFA, fast food, duration of dietary intervention, and vitamin D), were important contributing factors for FA.

Food allergy and infant feeding practices: Are they related?

BACKGROUND

Immunoglobulin (Ig)E-mediated food allergy is a growing health problem affecting up to 10% of children. It is well-established that early introduction to peanuts and eggs from 4 months of age has a preventive effect. In contrast, there is no consensus about the effect of breastfeeding on food allergy development.

OBJECTIVE

To evaluate the effect of breastfeeding and cows' milk formula (CMF) feeding on the development of IgE-mediated food allergy.

METHODS

Infants in the Cow's Milk Early Exposure Trial were followed for 12 months. The cohort was divided according to parental feeding preferences for the first 2 months of life: group 1: exclusive breastfeeding (EBF); group 2: breastfeeding with at least 1 daily meal of CMF; and group 3: feeding with CMF only.

RESULTS

Among a total of 1989 infants, 1071 were on EBF (53.8%), 616 were breastfed with addition of CMF (31%), and 302 were fed with CMF only (15.2%), from birth. By 12 months, 43 infants developed an IgE-mediated food allergy (2.2%); 31 in the EBF group (2.9%), 12 in the breastfeeding and CMF combined group (1.9%), and none in the CMF feeding-only group (P = .002). Family atopic comorbidity did not affect the results.

CONCLUSION

In this prospective cohort, breastfed infants developed significantly higher rates of IgE-mediated food allergy during the first year of life. Perhaps the mechanism is related to compounds ingested by the mother and secreted in the breastmilk. Future larger cohorts should validate these results and offer the lactating mother recommendations.

TRIAL REGISTRATION

The COMEET study and its derivatives were approved by the Ethics Committee of Meir Medical Center, IRB number 011-16-MMC. It was registered at the National Institutes of Health Clinical Trials Registry: NCT02785679.

Obesity-induced hyperglycemia impairs oral tolerance induction and aggravates food allergy

Obesity and type 2 diabetes (T2D) have been found to be associated with abnormalities in several organs, including the intestine. These conditions can lead to changes in gut homeostasis, compromising tolerance to luminal antigens and increasing susceptibility to food allergies. The underlying mechanisms for this phenomenon are not yet fully understood. In this study, we investigated changes in the intestinal mucosa of diet-induced obese mice and found that they exhibited increased gut permeability and reduced Treg cells frequency. Upon oral treatment with ovalbumin (OVA), obese mice failed to develop oral tolerance. However, hyperglycemia treatment improved intestinal permeability and oral tolerance induction in mice. Furthermore, we observed that obese mice exhibited a more severe food allergy to OVA, and this allergy was alleviated after treatment with a hypoglycemic drug. Importantly, our findings were translated to obese humans. Individuals with T2D had higher serum IgE levels and downregulated genes related to gut homeostasis. Taken together, our results suggest that obesity-induced hyperglycemia can lead to a failure in oral tolerance and to exacerbation of food allergy. These findings shed light on the mechanisms underlying the relationship among obesity, T2D, and gut mucosal immunity, which could inform the development of new therapeutic approaches.

Food Allergens in Ultra-Processed Foods According to the NOVA Classification System: A Greek Branded Food Level Analysis

Ultra-processed foods' (UPFs') consumption has been positively linked to the presence of allergic symptoms, but it is yet unknown whether this is linked to their nutritional composition or allergen load. This study used the ingredient lists available in the Greek Branded Food Composition Database, HelTH, to classify foods (n = 4587) into four grades of food processing (NOVA1-4) according to the NOVA System. Associations between NOVA grades and the presence of allergens (as an ingredient or trace) were studied. Overall, UPFs (NOVA4) were more likely to contain allergens than unprocessed foods, NOVA1 (76.1% vs. 58.0%). However, nested analyses among similar foods showed that in >90% of cases, processing degree was not linked to allergens' presence. Recipe/matrix complexity was more strongly linked to allergens' presence with NOVA4 foods declaring 1.3 allergenic ingredients vs. 0.4 allergenic ingredients in NOVA1 foods (p < 0.01). Exposure to trace allergens was more common for NOVA4 than NOVA1 foods (45.4% vs. 28.7%), but the extent of contamination was similar (2.3 vs. 2.8 trace allergens). Overall, UPFs are more complex mixtures with higher numbers of allergens per food and are more prone to cross-contamination. However, indicating a food's degree of processing is not sufficient to help identify allergen-free choices within the same subcategory.

Biologicals in IgE-mediated food allergy

PURPOSE OF REVIEW

A better understanding of the most recent scientific literature in the use of biological therapy in the treatment of patients with IgE-mediated food allergy.

RECENT FINDINGS

A systematic review and meta-analysis demonstrated safety and effectiveness of omalizumab in the treatment of food allergy. The findings support the potential use of omalizumab as a monotherapy or as an adjunct to oral immunotherapy in IgE-mediated cow's milk allergy. The potential use of other biologics in the management of food allergy is subject of speculation.

SUMMARY

Different biological therapies are under evaluation for food allergic patients. The advance in literature will guide for a personalized treatment in the near future. However, additional research is needed to better understand the best candidate for each treatment, the optimal dose and timing.

Establishment of Food Allergy Model in Dextran Sulfate Sodium Induced Colitis Mice

Food allergy (FA) has become a global food safety issue. Evidence suggests that inflammatory bowel disease (IBD) can increase the incidence of FA, but it is mostly based on epidemiological studies. An animal model is pivotal for unraveling the mechanisms involved. However, dextran sulfate sodium (DSS)-induced IBD models may cause substantial animal losses. To better investigate the effect of IBD on FA, this study aimed to establish a murine model to fit both IBD and FA symptoms. Firstly, we compared three DSS-induced colitis models by monitoring survival rate, disease activity index, colon length, and spleen index, and then eliminated the colitis model with a 7-day administration of 4% due to high mortality. Moreover, we evaluated the modeling effects on FA and intestinal histopathology of the two models selected and found the modeling effects were similar in both the colitis model with a 7-day administration of 3% DSS and the colitis model with long-term administration of DSS. However, for animal survival reasons, we recommend the colitis model with long-term administration of DSS.

Cow's milk allergy skin tests: fresh milk, commercial extracts, or both?

BACKGROUND

The diagnosis of food allergy is based on a history of immediate allergic reaction following food ingestion, and skin prick test (SPT) demonstrating sensitization with commercial extracts (CE) or fresh food (FF). For most food allergens, the SPT with FF is considered more accurate and predictive. Regarding cow's milk, the results are inconclusive. This retrospective study aimed to evaluate the accuracy of SPT with fresh milk compared to CE (cow's milk and casein) for evaluation of cow's milk allergy (CMA).

METHODS

This study summarized the medical records of children, diagnosed with CMA. The data include demographics, skin tests and oral food challenge results, as well as atopic comorbidities.

RESULTS

Records of 698 patients with the diagnosis of CMA were reviewed, 388 fulfilled the inclusion criteria. Overall, 134 patients (34.54%) had an additional atopic disease. The SPT wheal size with fresh milk was significantly larger than with CE (cow's milk and casein) at first evaluation or before oral food challenge (OFC). Combination of SPT results (CE and FF) gave the maximal odds ratio for reaction during OFC and SPT with fresh milk alone gave the minimal OR (34.18 and 4.74, respectively).

CONCLUSIONS

SPT with CE for CMA evaluation is more reliable than SPT performed with fresh milk. In patients suspected of having IgE-mediated CMA, before deciding on performing OFC, it is advised to perform SPT with at least two different extracts, and always include casein. Fresh milk can serve as a backup if commercial extracts are not available. In cases that the SPT with fresh milk is 3 mm or less, there is 93.3% chance that the OFC will pass without reaction. Trial registration This study protocol was reviewed and approved by the Ethics Committee of Meir Medical Center, IRB Number 0083-18 MMC.

Oral tolerance and oral immunotherapy for food allergy: Evidence for common mechanisms?

Food allergies affect up to 10% of the US population, can be life-threatening, and have a significant negative impact on quality of life. Delayed dietary introduction of foods in childhood can hinder the induction of oral tolerance, an active regulatory response to foods that prevents the development of food allergy. Some children outgrow their food allergies naturally, while many others have persistent, lifelong food allergy for which there are few therapeutic options. Oral immunotherapy (OIT) is a therapeutic approach of giving increasing amounts of food to attempt to desensitize the allergic individual. In this review, we focus on the immune mechanisms common to oral tolerance and response to oral immunotherapy, with the objective of determining whether true tolerance can be achieved after food allergy has been established.

Perinatal exposure to foodborne inorganic nanoparticles: A role in the susceptibility to food allergy?

Food allergy (FA) is an inappropriate immune response against dietary antigens. Various environmental factors during perinatal life may alter the establishment of intestinal homeostasis, thereby predisposing individuals to the development of such immune-related diseases. Among these factors, recent studies have emphasized the chronic dietary exposure of the mother to foodborne inorganic nanoparticles (NP) such as nano-sized silicon dioxide (SiO₂), titanium dioxide (TiO₂) or silver (Ag). Indeed, there is growing evidence that these inorganic agents, used as food additives in various products, as processing aids during food manufacturing or in food contact materials, can cross the placental barrier and reach the developing fetus. Excretion in milk is also suggested, hence continuing to expose the neonate during a critical window of susceptibility. Due to their immunotoxical and biocidal properties, such exposure may disrupt the host-intestinal microbiota's beneficial exchanges and may interfere with intestinal barrier and gut-associated immune system development in fetuses then the neonates. The resulting dysregulated intestinal homeostasis in the infant may significantly impede the induction of oral tolerance, a crucial process of immune unresponsiveness to food antigens. The current review focuses on the possible impacts of perinatal exposure to foodborne NP during pregnancy and early life on the susceptibility to developing FA.

Effects of Avenanthramide on the Small Intestinal Damage through Hsp70-NF-κB Signaling in an Ovalbumin-Induced Food Allergy Model

A food allergy is caused by an abnormal immune reaction and can induce serious intestinal inflammation and tissue damage. Currently, the avoidance of food allergens is still the most effective way to prevent or reduce allergic symptoms, so the development of new strategies to treat allergies is important. Avenanthramide (AVA) is a bioactive polyphenol derived from oats with a wide range of biological activities; however, it is still not clear whether or how AVA alleviates intestinal damage under allergic situations. The aim of this study was to explore the effect of AVA on the small intestinal damage in an ovalbumin (OVA)-induced food allergy model and its mechanism. In experiment 1, 10 mg/kg bw and 20 mg/kg bw doses of AVA both decreased the serum levels of OVA-specific IgE, histamine, and prostaglandin D induced by OVA. The AVA administration relieved inflammation indicated by the lower serum concentrations of pro-inflammatory cytokines including interleukin-1β, IL-6, and tumor necrosis factor-α. The levels of tight junction proteins including Claudin-1, ZO-1, and Occludin in the jejunum were elevated after AVA administration, accompanied by the improved intestinal morphology. Furthermore, AVA elevated the protein expression of heat shock protein 70 (Hsp70) and inhibited the phosphorylation of nuclear factor kappa-B (NF-κB), thus the apoptozole, which a Hsp70 inhibitor, was applied in experiment 2 to assess the contribution of Hsp70-NF-κB signaling to the effects of AVA. In the experiment 2, the inhibition of Hsp70 signaling treatment abolished the beneficial effects of AVA on the small intestinal damage and other allergic symptoms in mice challenged with OVA. Taken together, our results indicated that AVA exerted an intestinal protection role in the OVA-induced allergy, the mechanism of which was partly mediated by the Hsp70-NF-κB signaling.

Relationship between maternal-infant gut microbiota and infant food allergy

The gut microbiota plays a crucial role in food allergies. We sought to identify characteristics of the maternal gut microbiota in the third trimester and the infant gut microbiota in early life and the association of these microbiotas with infant food allergy. A total of 68 healthy pregnant women and their full-term newborns were selected from a cohort of 202 mother-infant pairs; among them, 24 infants had been diagnosed with food allergy within 1 year of age, whereas 44 infants were healthy without allergic symptoms. We collected 65 maternal fecal samples before delivery and 253 infant fecal samples at five time points following birth. Fecal samples were microbiologically analyzed using 16S rRNA gene sequencing. Holdemania abundance in the maternal gut microbiota in the third trimester was significantly higher in the non-allergy group than in the food allergy group (P = 0.036). In the infant gut microbiota, Holdemania was only found in meconium samples; its abundance did not differ significantly between the two groups. The change in the abundance of Actinobacteria over time differed between the non-allergy and food allergy groups (FA, P = 0.013; NA, P = 9.8 × 10-5), and the change in the abundance of Firmicutes over time differed significantly in the non-allergy group (P = 0.023). The abundances of genera Anaerotruncus, Roseburia, Ruminococcus, and Erysipelotricaceae were significantly different between the non-allergy and food allergy groups at different time points. Our results showed that maternal carriage of Holdemania during the third trimester strongly predicted the absence of food allergies in infants; there was no correlation between the presence of food allergies and the abundance of Holdemania in the infant gut microbiota. More dynamic fluctuations in phyla Actinobacteria and Firmicutes early in life protect against food allergy. Thus, the enrichment of the infant gut microbiota early in life with short-chain fatty acid-producing bacteria may be beneficial in preventing the development of food allergies in infants.

Allergies to food and airborne allergens in children and adolescents: role of epigenetics in a changing environment

Allergic diseases affect millions of children and adolescents worldwide. In this Review, we focus on allergies to food and airborne allergens and provide examples of prevalence trends during a time when climate change is of increasing concern. Profound environmental changes have affected natural systems in terms of biodiversity loss, air pollution, and climate. We discuss the potential links between these changes and allergic diseases in children, and the clinical implications. Several exposures of relevance for allergic disease also correlate with epigenetic changes such as DNA methylation. We propose that epigenetics could be a promising tool by which exposures and hazards related to a changing environment can be captured. Epigenetics might also provide promising biomarkers and help to elucidate the mechanisms related to allergic disease initiation and progress.

Early life environmental antibiotic exposure and preschool allergic diseases: A biomonitoring-based prospective study in eastern China

Background

Globally, the prevalence of allergic diseases remains high, as does the level of environmental antibiotics. It has been found that clinical antibiotic application may increase preschool allergy risk. However, few biomonitoring studies have been conducted about the association between early life environmental trace dose antibiotic exposure and preschool allergy.

Objective

To analyze the association between prenatal environmental antibiotic levels and allergic diseases using logistic regression models.

Methods

A total of 743 pregnant women and their offspring from the Shanghai Allergy Birth Cohort completed five years follow-up, and 251 mother-infant pairs were finally included. Maternal urine samples were collected for 15 antibiotic quantitative measurements using liquid chromatography-tandem mass spectrometry. The high-antibiotic group was defined as having at least half of antibiotics exceeding the median concentration. Allergic diseases were assessed by clinicians through clinical history, standardized questionnaires, and annual physical examinations until the age of five. Skin-prick-test (SPT) was performed at 5 years old.

Results

The incidence of allergic diseases was generally higher in the high-antibiotic than that in the low-antibiotic group. Compared to the low-comprehensive antibiotic group, children in the high-antibiotic group were weakly associated with allergic diseases but had a 6-fold increased risk of food allergens sensitivity (OR: 7.09, 95% CI: 1.59, 31.74). Association of above-median single prenatal antibiotic concentration exposure and allergic diseases was also observed (azithromycin and asthma, OR: 2.72, 95% CI: 1.15, 6.42; enrofloxacin and wheeze, OR: 2.22, 95% CI: 1.22, 4.05; trimethoprim and atopic dermatitis, OR: 2.00, 95% CI: 1.08, 3.71). Moreover, children with higher prenatal norfloxacin levels were more sensitive to food allergens (OR: 5.52, 95%CI: 1.54, 19.71).

Conclusion

Early-life environmental antibiotic exposure may be correlated with an increased risk of asthma, wheeze, atopic dermatitis, and SPT positivity for food allergens in 5-year-old children.

A portable electrochemiluminescence aptasensor for β-lactoglobulin detection

Cow’s milk allergy is one of the most common food allergies in children with a prevalence of around 2.5%. Milk contains several allergens; the main ones are caseins and β-lactoglobulin (β-LG). At regulatory level, β-LG is not explicitly named, but milk is included in the list of substances or products causing allergies or intolerances. Hence, the presence of β-LG can be a useful marker for determining the presence of milk in food. In this work, we present an aptasensor based on electrochemiluminescence (ECL) for the quantification of β-LG in real food matrices displaying integrated advantages consisting of high specificity, good sensitivity, portability, and cost effectiveness. The performance and applicability of this sensor were tested by analyzing a sample of skimmed milk and an oat-based drink proposed as a vegetable substitute for milk of animal origin. We obtained a linear correlation between the intensity of the signal and the concentration of β-LG standard solutions (y = x * 0.00653 + 1.038, R² = 0.99). The limit of detection (LOD) and the limit of quantification (LOQ) were found to be 1.36 and 4.55 μg L⁻¹, respectively.

Biomarkers in oral immunotherapy

Food allergy (FA) is a global health problem that affects a large population, and thus effective treatment is highly desirable. Oral immunotherapy (OIT) has been showing reasonable efficacy and favorable safety in most FA subjects. Dependable biomarkers are needed for treatment assessment and outcome prediction during OIT. Several immunological indicators have been used as biomarkers in OIT, such as skin prick tests, basophil and mast cell reactivity, T cell and B cell responses, allergen-specific antibody levels, and cytokines. Other novel indicators also could be potential biomarkers. In this review, we discuss and assess the application of various immunological indicators as biomarkers for OIT.

Bifidobacterium animalis KV9 and Lactobacillus vaginalis FN3 alleviated β-lactoglobulin-induced allergy by modulating dendritic cells in mice

Food allergy is a serious public health problem because of its high incidence and risk. Probiotics can induce immune regulation in patients with allergic diseases, but its mechanism is not fully clear. In this paper, β-lactoglobulin (β-LG)-sensitized mice were used as models to explore the mechanism of Bifidobacterium animalis KV9 (KV9) and Lactobacillus vaginalis FN3 (FN3) on reducing allergic reactions and regulating immune cell function. The results showed that oral administration of KV9 and FN3 significantly reduced the scores of allergic symptoms, hypothermia symptoms, and serum levels of β-LG-specific immunoglobulins E (β-LG-sIgE), histamine, and mast cell protease in allergic mice. Flow cytometry analysis of intestinal dendritic cells (DCs) showed that the proportion of CD11c+major histocompatibility complex (MHC)-II+DCs, CD11c+CD80+DCs, and CD11c+ CD86+DCs increased after KV9 and FN3 intervention, indicating that the strains induced immature DCs and decreased the antigen-presenting capacity of DCs. Meanwhile, the toll-like receptor 4 (TLR4)-NF-κB signaling pathway was activated in DCs. The secretion of interleukin-12 (IL-12) was significantly increased, while interleukin-4 (IL-4) was decreased by DCs after KV9 and FN3 intervention, indicating that DCs have the potential to promote T-cell differentiation into T helper type 1 (Th1) cells. Furthermore, the proportion of CD3+CD8−IFN-γ+ T cells in the spleen increased, while CD3+CD8−IL-4+T cells decreased after oral administration of KV9 and FN3, correcting the T helper type 2 (Th2)-skewed immune responses. These results indicate that KV9 and FN3 reduce β-LG-induced allergic symptoms in mice, and suggest that the two potential probiotics might be used as an alternative therapeutic agent for mitigating food allergy.

Comparative Analysis of Glycosylation Affecting Sensitization by Regulating the Cross-Reactivity of Parvalbumins in Turbot (Scophthalmus maximus), Conger Eel (Conger myriaster) and Sea Bass (Micropterus salmoides)

Parvalbumin (PV) is the most common allergen in fish. Some patients with fish allergy are allergic to only one species of fish but are tolerant to others; however, the underlying mechanism has not been identified. This study showed that three types of glycated fishes' PV showed a similar decrease in immunoglobulin E (IgE) binding. Glycosylation could improve the simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) digestion resistance of fishes' PV. We also discovered that the cross-reactivity between eel and turbot was weaker than that of bass; glycosylation can reduce cross-reactivity between eel/bass and turbot by downregulating Th2 cytokines and upregulating Th1 cytokines as well as downregulating the expression of G-T PV, G-E PV, G-B PV of IL-4 (94.31 ± 3.16, 73.26 ± 0.91, 94.95 ± 3.03 ng/mL), and IL-13 (38.84 ± 0.75, 33.77 ± 0.71, 36.51 ± 0.50 ng/mL) and upregulating the expression of IFN-γ (318.01 ± 3.46, 387.15 ± 3.30, 318.01 ± 4.21 ng/mL) compared with T PV, respectively. This study showed that glycosylation affected sensitization by regulating the cross-reactivity of parvalbumins.

Fucoxanthin Prevents the Ovalbumin-Induced Food Allergic Response by Enhancing the Intestinal Epithelial Barrier and Regulating the Intestinal Flora

This study aimed to determine whether fucoxanthin alleviated ovalbumin (OVA)-induced food allergy (FA) and explored the possible mechanisms. The results indicated that supplementation with fucoxanthin at 10.0-20.0 mg/kg per day for 7 weeks inhibited food anaphylaxis and the production of immunoglobulin (Ig) E, IgG, histamine, and related cytokines while alleviating allergic symptoms in sensitized mice. Fucoxanthin enhanced the intestinal epithelial barrier by up-regulating tight junction (TJ) protein expression and promoting regenerating islet-derived protein III-gamma (RegIIIγ) and secretory IgA (sIgA) secretion. In addition, fucoxanthin induced the secretion of anti-inflammatory factors (interleukin (IL)-10 and transforming growth factor β (TGF-β)) by regulatory T (Treg) cells and decreased the pro-inflammatory factor levels (IL-4, tumor necrosis factor-α (TNF-α), IL-17, and IL-1β), ameliorating intestinal inflammation. Compared with the model group, beneficial bacteria, such as Lactobacillaceae, increased in the intestinal flora, while pathogenic bacteria like Helicobacteraceae, Desulfovibrionaceae, and Streptococcaceae decreased. Therefore, fucoxanthin may effectively prevent FA by enhancing the intestinal epithelial barrier and reshaping the intestinal flora.

Current and Future Strategies for the Diagnosis and Treatment of the Alpha-Gal Syndrome (AGS)

The α-Gal syndrome (AGS) is a pathognomonic immunoglobulin E (IgE)-mediated delayed anaphylaxis in foods containing the oligosaccharide galactose-α-1,3-galactose (α-Gal) such as mammalian meat or dairy products. Clinical presentation of AGS can also comprise immediate hypersensitivity due to anticancer therapy, gelatin-containing vaccines or mammalian serum-based antivenom. The IgE initial sensitization is caused by hard-bodied tick bites and symptomatic individuals typically develop delayed pruritus, urticaria, angioedema, anaphylaxis, malaise or gut-related symptoms. Due to inapparent presentation, delayed reactions and a wide variety of patients´ clinical history, the AGS diagnosis and treatment remain challenging. This review covers not only current diagnostic methods used for AGS such as the skin prick test (SPT), the oral food challenge (OFC), anti-α-Gal IgE levels measurement and the basophil activation test (BAT), but also potentially relevant next-generation diagnostic tools like the mast cell activation test (MAT), the histamine-release (HR) assay, omics technologies and model-based reasoning (MBR). Moreover, it focuses on the therapeutical medical and non-medical methods available and current research methods that are being applied in order to elucidate the molecular, physiological and immune mechanisms underlying this allergic disorder. Lastly, future treatment and preventive tools are also discussed, being of utmost importance for the identification of tick salivary molecules, with or without α-Gal modifications, that trigger IgE sensitivity as they could be the key for further vaccine development. Bearing in mind climate change, the tick-host paradigm will shift towards an increasing number of AGS cases in new regions worldwide, which will pose new challenges for clinicians in the future.

Versatile Application of Nanobodies for Food Allergen Detection and Allergy Immunotherapy

The unique characteristics of camelid heavy-chain only antibody (HCAb) derived nanobodies (Nbs) have facilitated their employment as tools for research and application in extensive fields including food safety inspection, diagnosis and therapy of diseases, etc., to develop immune detecting techniques or alternative candidates of conventional antibodies as diagnostic and therapeutic reagents. The wide application in the fields of food allergen inspection and immunotherapy has not been addressed as not much results published in the literature. The robust properties and straightforward selecting strategy of Nbs impel the advantageous employment compared with monoclonal antibodies (mAbs) to establish immunoassay and serve as blocking antibodies to compete immunoglobulin E (IgE) binding epitopes on food allergens. More and more efforts have been invested to develop specific Nbs against food allergen proteins, such as macadamia allergen of Mac i 1, peanut allergen of Ara h 3, and lupine allergen of Lup an 1, which demonstrated the potential of Nbs for research and application in food allergen surveillance. Meanwhile, the paratopes of Nbs preferably targeting the unique epitopes of food allergens can provide more possibilities to serve as blocking antibodies to shield IgE binding epitopes for food allergy immunotherapy. Regardless, the research and application of Nbs in the field of food allergen and allergic reactions are expected to attract dramatic focus and produce promising research outputs.

Quantitative In Silico Evaluation of Allergenic Proteins from Anacardium occidentale, Carya illinoinensis, Juglans regia and Pistacia vera and Their Epitopes as Precursors of Bioactive Peptides

The aim of the study presented here was to determine if there is a correlation between the presence of specific protein domains within tree nut allergens or tree nut allergen epitopes and the frequency of bioactive fragments and the predicted susceptibility to enzymatic digestion in allergenic proteins from tree nuts of cashew (Anacardium occidentale), pecan (Carya illinoinensis), English walnut (Juglans regia) and pistachio (Pistacia vera) plants. These bioactive peptides are distributed along the length of the protein and are not enriched in IgE epitope sequences. Classification of proteins as bioactive peptide precursors based on the presence of specific protein domains may be a promising approach. Proteins possessing a vicilin, N-terminal family domain, or napin domain contain a relatively low occurrence of bioactive fragments. In contrast, proteins possessing the cupin 1 domain without the vicilin N-terminal family domain contain a relatively high total frequency of bioactive fragments and predicted release of bioactive fragments by the joint action of pepsin, trypsin, and chymotrypsin. This approach could be utilized in food science to simplify the selection of protein domains enriched for bioactive peptides.

Effects of fucoidans and alginates from Sargassum graminifolium on allergic symptoms and intestinal microbiota in mice with OVA-induced food allergy

Food allergy has been one of the main problems threatening people's health in recent years. However, there is still no way to completely cure it at present. Therefore, the development of food allergy related drugs is still necessary. Sargassum graminifolium (SG) is a kind of polysaccharide rich marine brown alga used in food and medicine. Sargassum graminifolium polysaccharides (SGP) is mainly composed of fucoidans and alginic acid. In our study, we compared the activity of fucoidans and alginates from SG against OVA-induced food allergy in a mouse model, observed the regulatory effects of fucoidans and alginates from SG on the intestinal microbiota and summarized the possible role of the intestinal microbiota in the anti-food allergy process because polysaccharides can further act on the body through the intestinal microbiota. The results showed that fucoidans and alginates from SG could relieve the symptoms of allergy, diarrhea and jejunum injury significantly in mice with food allergy (p < 0.05). Furthermore, fucoidans at 500 mg kg-1 could reduce OVA-specific IgE and TNF-α levels significantly in the serum of food allergic mice (p < 0.05), while alginates could only significantly down-regulate serum OVA-specific IgE (p < 0.05). The results also showed that fucoidans had a stronger regulatory effect on the richness and diversity of the intestinal microbiota in food allergic mice compared to alginates at the same dose. In addition, fucoidans at 500 mg kg-1 had the most significant regulatory effect on Firmicutes, Lactobacillus and Alistipes in food allergic mice. These results suggested that fucoidans and alginates might regulate food allergy in mice through different pathways. Together, this study enriched the research on the action of alga-derived polysaccharides against food allergy.

Hypoallergenicity assessment of an extensively hydrolyzed whey-protein formula in cow's milk allergic infants

BACKGROUND

Extensively hydrolyzed formulas are recommended for the dietary management of infants with cow's milk allergy (CMA).

OBJECTIVES

Hypoallergenicity, growth, and gastrointestinal (GI) tolerability of a new extensively hydrolyzed whey-protein formula (eHWF) in CMA children were assessed.

METHODS

In this prospective, randomized, international, multi-center study (Trial NL3889), 34 children with confirmed CMA (74% IgE-mediated) underwent a double-blind, placebo-controlled food challenge (DBPCFC) with an eHWF developed with non-porcine enzymes, supplemented with prebiotic short-chain galacto- and long-chain fructo-oligosaccharides (0.8 g/L, ratio 9:1), arachidonic acid (0.35/100 g), and docosahexaenoic acid (0.35/100 g). If tolerant to the eHWF, children participated in a 7-day open food challenge with this eHWF. Anthropometrics and GI tolerability were assessed in an optional 16-weeks follow-up.

RESULTS

Of the 34 children who started the DBPCFC with the eHWF, 25 subjects (19 boys, mean age: 61 weeks, 18 with IgE-mediated CMA) completed the DBPCFC and 7-day open challenge without major protocol deviations and tested negative at both challenges. One child experienced a late moderate eczematous allergic reaction in the optional follow-up period, indicating the need for close monitoring of subjects starting new formula. Weight and length gain followed the World Health Organization growth curves. Changes in frequency and consistency of stools upon test formula intake were transient.

CONCLUSIONS

The newly developed eHWF is a suitable option in CMA treatment as all subjects tolerated the product. This result is in line with the international criteria for hypoallergenicity (American Academy of Pediatrics) that state that more than 90% of CMA children must tolerate the formula. Use of the formula is also associated with normal growth curves and GI tolerability.

TRIAL REGISTRATION

Trial NL3889, https://www.trialregister.nl/trial/3889.

Cross-Reacting Carbohydrate Determinants Inhibitor Can Improve the Diagnostic Accuracy in Pollen and Food Allergy

Background

Cross-reacting carbohydrate determinants (CCD) exist in some pollen and food allergens, but they do not contribute to allergic symptoms. However, CCD can induce specific IgE (sIgE) production and may lead to incorrect allergen diagnosis and treatment. CCD inhibitor is a specific antibody adsorbent which can preclude CCD from binding to sIgE. Currently, the data of CCD inhibition in allergen sIgE test are limited.

Methods

The allergic patients with positive skin prick reactions to two or more pollen and/or food allergen extracts were included in our study. Their sera were obtained and sIgE was tested with an allergen panel that included 29 single and mixed allergens (MEDIWISS Analytic GmbH, China) before and after CCD inhibition. The changes of sIgE against these allergens and the correlations of sIgEs to clinical symptoms were analyzed.

Results

A total of 44 patients were included and 36 (81.82%) of those were multi-sensitized to house dust mites and pollen allergens based on skin prick tests. The sIgE levels and positive rates against most pollen and food allergens were significantly lower after CCD inhibition. The sIgE levels of pollen were positively correlated to those of food allergens before CCD inhibition. However, these correlations were weakened or no longer existed after CCD inhibition. The sIgE against pollen and food allergens showed significantly higher consistency with clinical symptoms after CCD inhibition.

Conclusion

Cross-sensitization caused by CCD is widespread in pollen and food. CCD inhibition test can improve the diagnostic accuracy of pollen and food allergy.

Association Between Breastmilk Microbiota and Food Allergy in Infants

Regulating the composition of human breastmilk has the potential to prevent allergic diseases early in life. The composition of breastmilk is complex, comprising varying levels of oligosaccharides, immunoactive molecules, vitamins, metabolites, and microbes. Although several studies have examined the relationship between different components of breastmilk and infant food allergies, few have investigated the relationship between microorganisms in breastmilk and infant food allergy. In the present study, we selected 135 healthy pregnant women and their full-term newborns from a cohort of 202 mother-infant pairs. Among them, 69 infants were exclusively breastfed until 6 mo after birth. At follow-up, 11 of the 69 infants developed a food allergy in infancy while 22 showed no signs of allergy. Thirty-three breastmilk samples were collected within 1 mo after delivery, and 123 infant fecal samples were collected at five time points following their birth. These samples were analyzed using microbial 16S rRNA gene sequencing. The abundance and evenness of the milk microbiota and the number of differential bacteria were higher in the breastmilk samples from the non-allergy group than in those from the food allergy group. The non-allergy group showed relatively high abundance of Bifidobacterium, Akkermansia, Clostridium IV, Clostridium XIVa, Veillonella, and butyrate-producing bacteria such as Fusobacterium, Lachnospiraceae incertae sedis, Roseburia, and Ruminococcus. In contrast, the abundance of Proteobacteria, Acinetobacter, and Pseudomonas in breastmilk was higher in the food allergy group. A comparison of the changes in dominant differential breastmilk microbiota in the intestinal flora of the two groups of infants over time revealed that the changes in Bifidobacterium abundance were consistent with those in the breastmilk flora. Functional pathway prediction of breastmilk microflora showed that the enhancement of the metabolic pathways of tyrosine, tryptophan, and fatty acids was significantly different between the groups. We suggest that changes in the breastmilk microbiota can influence the development of food allergies. Breastmilk contains several microbes that have protective effects against food allergies, both by influencing the colonization of intestinal microbiota and by producing butyrate. This study may provide new ideas for improving infant health through early intervention with probiotics.

Fish allergens of turbot (Scophthalmus maximus) parvalbumin triggers food allergy via inducing maturation of bone marrow derived dendritic cells and driving Th2 immune response

Aquatic food allergy has become a key food safety problem and therefore it is urgent to study the mechanism of aquatic food allergy. Turbot parvalbumin (PV) is a major marine food allergen that could cause allergic reactions but the cellular and molecular mechanisms remain to be defined. In this study, we used flow cytometry and ELISA, a coupled co-culture system of dendritic cells and T cells, and revealed that PV could promote the maturation of dendritic cells, mainly by inducing bone marrow-derived dendritic cells (BMDCs) to express MHC II and CD86, and promote the cytokines/chemokines IL-6, IFN-γ, IL-23, and IL-12p70, whereas inhibiting TNF-α expression. Our results suggested that murine BMDCs play a crucial role in the effect of PV on the induction of Th2 responses.

Oral immunotherapy in children with a food allergy-Where do we stand? - Review

The number of hospitalisations due to an anaphylactic reaction to food is continuously increasing. Therefore, there is an urgent need to seek effective therapy. Currently, the only way to treat food allergies is to avoid allergens and to administer intramuscular adrenaline if an accidental allergen intake occurs. The only causal therapeutic strategy is specific oral immunotherapy. An increasing amount of data confirms this therapy's effectiveness and safety, but the results remain inconclusive due to the lack of long-term follow-up. In this state-of-the-art review, we briefly summarise the latest placebo-controlled randomised controlled trials on oral immunotherapy (OIT) to treat food allergy. During the paper's review, we asked the following questions: does the therapy permanently increase the amount of allergen consumed without symptoms? Does it significantly increase or decrease the occurrence of severe systemic reactions - requiring the administration of adrenaline or hospitalisation? Many authors describe outcomes such as an increase in the amount of allergen that can be safely ingested; however, significant clinical benefits such as decreased hospitalisations or anaphylaxis incidence are rarely included in the results. To date, there is no unified protocol of therapy, which makes comparisons between studies difficult because of significant differences in types, doses, and routes of administration of the allergen, timeline for up-dosing and maintenance, duration of the therapy, and primary outcomes of OIT.

The role of the pediatric cutaneous and gut microbiomes in childhood disease: A review

OBJECTIVE

Infancy and early childhood are crucial periods in the development of the human microbiome and shape the trajectory of microbial colonization, immune system development, and systemic disease. We review the development of the skin and gut microbiomes, their connection to the immune system, and their relevance to common pediatric pathologies.

FINDINGS

Beginning after birth, and likely even in utero, colonization of the skin and the gut occur in parallel, influenced by external factors. This colonization, in turn, dictates maturation of the immune system and contributes to conditions from atopic dermatitis to sepsis. Emerging literature is identifying links between the gut and skin microbiomes.

CONCLUSION

The gut and skin microbiomes are associated with pediatric disease states. Immune and microbial plasticity make this unique period an ideal target for intervention. Investigating the purposeful manipulation of the pediatric microbiome may lead to novel treatment and prevention strategies.

Microfluidic origami nano-aptasensor for peanut allergen Ara h1 detection

In this study, an origami microfluidic electrochemical nano-aptasensor was developed for the rapid detection of the peanut allergen Ara h1. Specifically, the microfluidic aptasensor was fabricated through sequential folding of a piece of chromatography paper substrate patterned with microchannel and screen-printed electrodes. Aptamer-decorated black phosphorus nanosheets (BPNSs) were electrodeposited onto the paper-based electrode surface as sensing probes for enhanced electrochemical detection and high specificity and selectivity. Critical design parameters (the concentration of probe, time for self-assembly of aptamer and reaction time) were investigated to optimize the aptasensor performance. The prepared aptasensor was able to complete detection within 20 min and demonstrated a linear range from 50 ~ 1000 ng/mL with a detection limit of 21.6 ng/mL. The aptasensor was successfully used to detect the Ara h1 spiked cookie dough sample. The proposed method reduces the gap between complex lab testing and food allergen analysis at the point of need.

Mechanism on the Allergenicity Changes of α-Lactalbumin Treated by Sonication-Assisted Glycation during In Vitro Gastroduodenal Digestion

Physical-assisted chemical modification is effective to reduce the allergenicity of α-lactalbumin (ALA). However, there are few in-depth studies on the allergenicity changes of physical-assisted chemical-modified ALA during digestion. The effect of gastroduodenal digestion on the allergenicity changes of ALA treated by sonication-assisted glycation was assessed. Digestion of both ALA and its glycated forms generated peptide fractions, and intact undigested glycated ALA in the hydrolysates still covalently bound to d-galactose. High-resolution mass spectrometry revealed that a higher glycation degree was discovered in sonication-preprocessed ALA compared to native ALA. Enzyme-linked immunosorbent assay and basophil degranulation showed that sonication-assisted glycation could significantly reduce ALA allergenicity. The allergenicity of both gastric and gastroduodenal hydrolysates was further increased, and the hydrolysates of sonication-assisted glycated ALA showed the lowest allergenicity. The reason could be the shielding effect of the linear epitope found to be caused by a higher glycation degree; although linear epitopes were exposed, d-galactose covalently bound to intact undigested glycated ALA in the hydrolysates retained its masking role. These results indicated that sonication-assisted glycation could be a promising method to prepare immunotherapeutic agents for allergen immunotherapy to achieve the purpose of allergy desensitization.

The use of biologics in food allergy

BACKGROUND

Food allergy continues to pose problems due to its increased frequency and its increasingly high severity. In this context, alongside the traditional avoidance strategies of allergenic foods and desensitization through the cautious progression of exposure to foods in the context of oral immunotherapy (OIT), alternative strategies have made their way in the last decades. We review the possibilities of intervention in food allergy with the use of biological drugs capable of interfering with the synthesis of IgE, with their mechanisms of action, or with complex biological mechanisms that lead to the establishment of a food allergy.

METHODS

Repeated Entrez PubMed searches using the template algorithm "Food allergy" and "biologics" or "Omalizumab" or "Dupilumab" or "milk desensitization" or "oral tolerance induction" or "oral immunotherapy" or "Etokimab" or "Tezepelumab" or "Quilizumab" or "Ligelizumab" or "Tralokinumab" or "Nemolizumab" or "Mepolizumab" or "Reslizumab" or "Benralizumab". The authors' clinical experience in paediatric allergy units of University hospitals was also drawn upon.

RESULTS

The landscape in this context has changed dramatically over the past 10 years. We have acquired knowledge mainly on the effect of different types of anti-IgE treatments in poliallergic patients with food allergy, and in patients treated with OIT. However, other mediators are being targeted by specific biologic treatments. Among them, the alarmins Il-33 and TSLP, IL-4 and IL-13, eosinophil-related molecules as IL-6, IL-8, IL-10, IL-12, and mostly IL-5, and integrins involved in the pathogenesis of eosinophilic gastrointestinal diseases (EGIDs), as SIGLEC-8.

CONCLUSIONS

The ever-better knowledge of the mechanisms of food allergy allowing these developments will improve not only the perspective of patients with the most serious immediate food allergies such as anaphylaxis, but also those of patients with related diseases such as atopic dermatitis, eosinophilic esophagitis, and EGIDs. Biologics are also intended to complement OIT strategies that have developed over the years.

Sensitisation patterns and allergy outcomes in pregnant women living in the urban area

Background

Worldwide, allergy affects more than one billion people, with particularly rising prevalence in industrialised areas. Specifically, young adults appear to be predominantly targeted for an allergy diagnosis. Allergic diseases in pregnancy are mainly pre-existing but could also occur de novo. The immunological changes while pregnant, with increased Th2 lymphocyte activity, can facilitate allergen sensitisation.

Objective

The aim of this study was to evaluate the pattern of specific IgE (sIgE) sensitisation to common inhalant and food allergens in pregnancy, and assess its relationship to self-reported allergic disease.

Methods

We assessed 200 pregnant women, aged 20–38 years (mean age = 29 years), participant of ELMA (Epigenetic Hallmark of Maternal Atopy and Diet) study, living in a metropolitan area, with no pregnancy associated metabolic complications, for total IgE and allergen specific IgE to 20 allergens.

Results

48% of pregnant women were sensitised to at least one allergen, at a cut-off point of 0.35 kU/L and they were assigned as atopic. However 42% in atopic group were not reporting any allergic disease. The most common inhalant allergens were: pollen (24.5%) and animal dander (23.5%). The most common food allergens were: cow’s milk (5.5%) and apples (4.5%). 7.5% of women reported asthma, 21.5% allergic rhinitis, 11.5% atopic dermatitis and 18.5% food allergy. 8.5% of were taking medication for asthma or allergies. Atopic dermatitis had the highest tendency to become more severe during pregnancy. Total IgE values were significantly higher in atopic women.

Conclusions

Allergic sensitisation is a common phenomenon in pregnancy. Some sensitisations could be asymptomatic. Further studies should investigate if sensitisation in mothers confers risks for immune alterations in their children.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13223-021-00547-0.

Thermoneutrality Alters Gastrointestinal Antigen Passage Patterning and Predisposes to Oral Antigen Sensitization in Mice

Food allergy is an emerging epidemic, and the underlying mechanisms are not well defined partly due to the lack of robust adjuvant free experimental models of dietary antigen sensitization. As housing mice at thermoneutrality (Tn) - the temperature of metabolic homeostasis (26-30°C) - has been shown to improve modeling various human diseases involved in inflammation, we tested the impact of Tn housing on an experimental model of food sensitization. Here we demonstrate that WT BALB/c mice housed under standard temperature (18-20°C, Ts) conditions translocated the luminal antigens in the small intestine (SI) across the epithelium via goblet cell antigen passages (GAPs). In contrast, food allergy sensitive Il4raF709 mice housed under standard temperature conditions translocated the luminal antigens in the SI across the epithelium via secretory antigen passages (SAPs). Activation of SI antigen passages and oral challenge of Il4raF709 mice with egg allergens at standard temperature predisposed Il4raF709 mice to develop an anaphylactic reaction. Housing Il4raF709 mice at Tn altered systemic type 2 cytokine, IL-4, and the landscape of SI antigen passage patterning (villus and crypt involvement). Activation of SI antigen passages and oral challenge of Il4raF709 mice with egg antigen under Tn conditions led to the robust induction of egg-specific IgE and development of food-induced mast cell activation and hypovolemic shock. Similarly, Tn housing of WT BALB/c mice altered the cellular patterning of SI antigen passage (GAPs to SAPs). Activation of SI antigen passages and the oral challenge of WT BALB/c mice with egg antigen led to systemic reactivity to egg and mast cell activation. Together these data demonstrate that Tn housing alters antigen passage cellular patterning and landscape, and concurrent oral exposure of egg antigens and SAP activation is sufficient to induce oral antigen sensitization.

Non-IgE- or Mixed IgE/Non-IgE-Mediated Gastrointestinal Food Allergies in the First Years of Life: Old and New Tools for Diagnosis

non-IgE and mixed gastrointestinal food allergies present various specific, well-characterized clinical pictures such as food protein-induced allergic proctocolitis, food protein-induced enterocolitis and food protein-induced enteropathy syndrome as well as eosinophilic gastrointestinal disorders such as eosinophilic esophagitis, allergic eosinophilic gastroenteritis and eosinophilic colitis. The aim of this article is to provide an updated review of their different clinical presentations, to suggest a correct approach to their diagnosis and to discuss the usefulness of both old and new diagnostic tools, including fecal biomarkers, atopy patch tests, endoscopy, specific IgG and IgG4 testing, allergen-specific lymphocyte stimulation test (ALST) and clinical score (CoMiss).