Food Allergy

Dynamic simulation and experimental studies of molecularly imprinted label-free sensor for determination of milk quality marker

Bovine serum albumin (BSA) has emerged as a biomarker for mammary gland health and cow quality, being recognized as a significant allergenic protein. In this study, a novel flexible molecular imprinted electrochemical sensor by surface electropolymerization using pyrrole (Py) as functional monomer, which can be better applied to the detection of milk quality marker BSA. Based on computational results, with regard to all polypyrrole (PPy) conformations and amino-acid positions within the protein, the BSA molecule remained firmly embedded into PPy polymers with no biological changes. The molecular imprinted electrochemical sensor displayed a broad linear detection range from 1.0 × 10-4 to 50 ng·mL-1 (R2 = 0.995) with a low detection limit (LOD) of 4.5 × 10-2 pg·mL-1. Additionally, the sensor was highly selective, reproducible, stable and recoverable, suggesting that it might be utilized for the evaluation of milk quality.

Inulin-gel-based oral immunotherapy remodels the small intestinal microbiome and suppresses food allergy

Despite the potential of oral immunotherapy against food allergy, adverse reactions and loss of desensitization hinder its clinical uptake. Dysbiosis of the gut microbiota is implicated in the increasing prevalence of food allergy, which will need to be regulated to enable for an effective oral immunotherapy against food allergy. Here we report an inulin gel formulated with an allergen that normalizes the dysregulated ileal microbiota and metabolites in allergic mice, establishes allergen-specific oral tolerance and achieves robust oral immunotherapy efficacy with sustained unresponsiveness in food allergy models. These positive outcomes are associated with enhanced allergen uptake by antigen-sampling dendritic cells in the small intestine, suppressed pathogenic type 2 immune responses, increased interferon-γ+ and interleukin-10+ regulatory T cell populations, and restored ileal abundances of Eggerthellaceae and Enterorhabdus in allergic mice. Overall, our findings underscore the therapeutic potential of the engineered allergen gel as a suitable microbiome-modulating platform for food allergy and other allergic diseases.

[Declaration of allergens on food labels: overview of Latin AmericaDeclaração de alergênicos na rotulagem de alimentos: panorama da América Latina]

Objective

Identify countries that have legislation on mandatory declarations of food allergens, irradiated foods, and transgenic foods on the nutritional labels of packaged foods.

Methods

Exploratory study reviewing the health regulations and technical standards for foods in Latin American countries in order to gather information on declarations of allergens, trace allergens, irradiated foods, and transgenic foods. The information search was carried out through the countries' government web pages. Presentation of the results is descriptive and narrative.

Results

Of the 19 countries reviewed, 89% require a declaration of allergens on their nutrition labeling, 76% have legislation that explicitly require a statement on trace allergens, and 82% follow Codex Alimentarius recommendations with some modifications of food categories.

Conclusions

Three pending challenges in the Region are: requiring statements on allergens as a food safety measure; making progress toward improved labeling of trace allergens; and ensuring universal availability of epinephrine.

The role of pediatricians in the diagnosis and management of IgE-mediated food allergy: a review

Importance

Food allergy can often cause a significant burden on patients, families, and healthcare systems. The complexity of food allergy management requires a multidisciplinary approach involving different types of healthcare providers, including allergists, dieticians, psychologists, nurses, family practitioners and, of particular relevance for this article, pediatric primary caretakers. Pediatricians may be the first-line healthcare providers for food allergy: strategies for management and guideline adherence have been highlighted.

Observations

This review article summarizes the up-to-date recommendations on the role of pediatricians in the diagnosis, management, and prevention of IgE-mediated food allergy. Early introduction of allergenic foods like peanut is known to be of importance to reduce the development of peanut allergy in infants, and pediatricians are essential for educating and supporting parents in this decision. In scenarios of limited allergist availability, as is often the case among rural, Medicaid and minority populations, pediatricians can assist in the evaluation and management of food allergy, and provide action plans, education and counselling for patients and families.

Conclusions and relevance

Pediatric primary caretakers play a key role in the diagnosis, management, and prevention of IgE-mediated food allergy. As more diagnostic tools and therapies in food allergy become available, the need for a multidisciplinary team is paramount to optimize patient care.

"Fluorescence-wavelength" label-free POCT tandem with "fluorescence-photothermal" nanobody-immunosensor for detecting BSA and β-lactoglobulin

Two carbon dots (CDs) (λEm = 525 nm, G-CDs and λEm = 640 nm, R-CDs) were synthesized from citric acid and urea. The bovine serum albumin (BSA) responsiveness of the R-CDs was used to develop a "fluorescence-wavelength" label-free point of care testing (POCT) for the detection of the milk quality marker BSA with the detection limit (LOD) of 4.89 μg/mL for fluorescence mode and 3.38 μg/mL for wavelength mode. In addition, R-CDs were found to have hydroxyl radical (·OH)-dependent fluorescence quenching properties, and a "fluorescence-photothermal" immunosensor based on nanobodies was constructed by introducing the fluorescence signal of R-CDs@BSA and the photothermal signal of oxTMB for the detection of β-lactoglobulin (β-LG) with the LOD of 0.034 ng/mL for fluorescence mode and 0.075 ng/mL for photothermal mode. The tandem detection of POCT and immunosensor enables the simultaneous and highly sensitive detection of BSA and β-LG after only simple dilution of less than 5 µL of sample.

A comprehensive review on glycation and its potential application to reduce food allergenicity

Food allergens are a major concern for individuals who are susceptible to food allergies and may experience various health issues due to allergens in their food. Most allergenic foods are subjected to heat treatment before being consumed. However, thermal processing and prolonged storage can cause glycation reactions to occur in food. The glycation reaction is a common processing method requiring no special chemicals or equipment. It may affect the allergenicity of proteins by altering the structure of the epitope, revealing hidden epitopes, concealing linear epitopes, or creating new ones. Changes in food allergenicity following glycation processing depend on several factors, including the allergen's characteristics, processing parameters, and matrix, and are therefore hard to predict. This review examines how glycation reactions affect the allergenicity of different allergen groups in allergenic foods.

Longitudinal assessment of early growth in children with IgE- and non-IgE-mediated food allergy in a healthy infant cohort

BACKGROUND

There are conflicting associations reported between food allergies (FAs) and poor growth, with some indication that children with multiple FAs are at highest risk.

OBJECTIVE

We analyzed longitudinal weight-for-length (WFL) trajectories from our healthy cohort to evaluate growth in children with IgE-mediated FAs and food protein-induced allergic proctocolitis (FPIAP), a non-IgE-mediated FA.

METHODS

Our observational cohort of 903 healthy newborn infants was prospectively enrolled to evaluate the development of FAs. Longitudinal mixed effects modeling was used to compare differences in WFL among children with IgE-FA and FPIAP, compared with unaffected children, through age 2.

RESULTS

Among the 804 participants who met inclusion criteria, FPIAP cases had significantly lower WFL than unaffected controls during active disease, which resolved by 1 year of age. In contrast, children with IgE-FA had significantly lower WFL than unaffected controls after 1 year. We also found that children with IgE-FA to cow's milk had significantly lower WFL over the first 2 years of age. Children with multiple IgE-FAs had markedly lower WFL over the first 2 years of age.

CONCLUSION

Children with FPIAP have impaired growth during active disease in the first year of age which resolves, whereas children with IgE-FA, particularly those with multiple IgE-FA, have impaired growth more prominently after the first year of age. It may be appropriate to focus nutritional assessment and interventions accordingly during these higher risk periods in these patient populations.

Evaluation and Management of Food Allergies in the Emergency Department

Food allergies are a common and serious cause of illness, accounting for an increasing number of emergency department visits annually. Although definite diagnosis lays outside of an emergency department visit, the clinical management of the most serious food allergies highlights emergency care. The staple of acute care remains epinephrine in association with antihistamines and steroids. The greatest threat remains undertreatment for this group of disorders and underutilization of epinephrine. Those who have been treated for a food allergy need a follow-up allergist evaluation, guidance of food avoidance, and avoidance of foods with cross-sensitivities as well as ready access to epinephrine.

The Implementation and Evaluation of a Stock Epinephrine for Schools Program in Maricopa County, Arizona

The increasing rate of food allergies in children, combined with the role of food as an integral part of the school day has led to the emergence of anaphylaxis as a daily threat to students, regardless of prior allergy diagnosis. Stock epinephrine-non-patient specific epinephrine auto-injectors that may be used during emergencies-is a means for schools to prepare for anaphylactic events and protect children with allergies. The Maricopa County Department of Public Health initiated the School Surveillance and Medication Program (SSMP), a data capture program, to facilitate the process of stocking epinephrine in schools. Spearheaded by the implementation efforts of the Kyah Rayne Foundation, program enrollment increased 146% between the 2020-2021 and 2021-2022 school years. The increased proportion of schools enrolled in the SSMP and the number of school personnel trained to administer epinephrine demonstrates the feasibility of school-centered stock epinephrine programs and validates strategies for increasing program uptake.

Structure and IgE Cross-Reactivity among Cashew, Pistachio, Walnut, and Peanut Vicilin-Buried Peptides

Peanut and tree-nut allergies are frequently comorbid for reasons not completely understood. Vicilin-buried peptides (VBPs) are an emerging family of food allergens whose conserved structural fold could mediate peanut/tree-nut co-allergy. Peptide microarrays were used to identify immunoglobulin E (IgE) epitopes from the N-terminus of the vicilin allergens Ara h 1, Ana o 1, Jug r 2, and Pis v 3 using serum from three patient diagnosis groups: monoallergic to either peanuts or cashew/pistachio, or dual allergic. IgE binding peptides were highly prevalent in the VBP domains AH1.1, AO1.1, JR2.1, and PV3.1, but not in AO1.2, JR2.2, JR2.3, and PV3.2 nor the unstructured regions. The IgE profiles did not correlate with diagnosis group. The structure of the VBPs from cashew and pistachio was solved using solution-NMR. Comparisons of structural features suggest that the VBP scaffold from peanuts and tree-nuts can support cross-reactivity. This may help understand comorbidity and cross-reactivity despite a distant evolutionary origin.

Prevalence of Parent-Reported Food Allergies and Associated Risk Predictors Among Children in Saudi Arabia

BACKGROUND AND OBJECTIVE

The worldwide prevalence of food allergies has been increasing recently. Due to limited data on food allergy (FA) in Saudi Arabia, this study was conducted to estimate the prevalence and risk factors of parent-reported food allergies and clinical manifestations in children in Taif, Saudi Arabia.

METHODOLOGY

A cross-sectional questionnaire-based observational study was conducted from July 2019 to December 2020. A total of 508 parents of school children (aged five to eight years) responded to the questions based on the child's health and food allergies.

RESULTS

FA (16.1%) was observed as the most common type of allergy among children. The prevalence of other atopic diseases was estimated at 30.5%. The most common allergy-causing foods were eggs (4.9%), peanuts (2.7%), and sesame (2.5%). Rash, itching without rash, and vomiting were the most common FA symptoms. The presence of childhood eczema (p< 0.0001), allergic rhinitis (p= 0.005), and the father's history of allergy (p= 0.005) were all significant and independent predictors/risk factors for FA among the studied children.

CONCLUSION

We noted substantial parents' concern with food allergies among children in Saudi Arabia, which necessitates the establishment of effective diagnosis and treatment strategies and primary prevention initiatives.

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.

Microbiome Therapeutics for Food Allergy

The prevalence of food allergies continues to rise, and with limited existing therapeutic options there is a growing need for new and innovative treatments. Food allergies are, in a large part, related to environmental influences on immune tolerance in early life, and represent a significant therapeutic challenge. An expanding body of evidence on molecular mechanisms in murine models and microbiome associations in humans have highlighted the critical role of gut dysbiosis in the pathogenesis of food allergies. As such, the gut microbiome is a rational target for novel strategies aimed at preventing and treating food allergies, and new methods of modifying the gastrointestinal microbiome to combat immune dysregulation represent promising avenues for translation to future clinical practice. In this review, we discuss the intersection between the gut microbiome and the development of food allergies, with particular focus on microbiome therapeutic strategies. These emerging microbiome approaches to food allergies are subject to continued investigation and include dietary interventions, pre- and probiotics, microbiota metabolism-based interventions, and targeted live biotherapeutics. This exciting frontier may reveal disease-modifying food allergy treatments, and deserves careful study through ongoing clinical trials.

Effectiveness of educational interventions for quality of life of parents and children with food allergy: A systematic review

BACKGROUND

Educational intervention along with medical treatment is important to improve the quality of life of children with food allergies and their parents. This systematic review was designed to investigate the effects of education programs for parents and children with food allergies to provide a direction for developing an intervention program to improve their quality of life.

METHODS

A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Relevant studies published between January 2010 and August 2021 were identified through a systematic search of 5 databases (PubMed, EMBASE, CINAHL, Cochrane Central Register of Controlled Trial, and Psycho Info).

RESULTS

A total of 2351 articles were identified. Of these, 9 met the inclusion criteria after duplicates were removed. Among these, only 2 studies, using the support and handbook provided, showed significant results on quality of life.

DISCUSSION

There is a lack of educational interventions for children with food allergies and their parents. Educational intervention, an essential intervention, can maximize medical treatment and improve overall quality of life. Hence, these interventions should be actively developed and applied in the future.

HLA-II Alleles Influence Physical and Behavioral Responses to a Whey Allergen in a Transgenic Mouse Model of Cow's Milk Allergy

The symptoms of food allergies vary significantly between individuals, likely due to genetic determinants. In humans, allergy development is initiated by antigen-presenting cells via class II human leukocyte antigen (HLA-II). The HLA-II gene is highly polymorphic, and its allelic variance is thought to influence the susceptibility of individuals to a particular allergen. However, whether antigen presentation by different HLA-II variants contributes to symptom variation is not clear. We hypothesized that HLA-II allelic variance affects symptom phenotypes, including immediate physical reactions and delayed behavioral changes, in individuals with food hypersensitivity. To test our hypothesis, male and female mice of three transgenic strains expressing an HLA-II variant, DR3, DR15, or DQ8, were used to establish a cow's milk allergy model. Mice were sensitized to a bovine whey allergen, β-lactoglobulin (BLG; Bos d 5), weekly for 5 weeks, followed by an acute oral allergen challenge. At 30 min post-challenge, BLG-sensitized DR3 mice showed moderate to severe anaphylaxis resulting in perioral redness, swelling, and death. In contrast, DQ8 and DR15 mice were generally asymptomatic. The production of allergen-specific immunoglobulins was also HLA- and sex-dependent. Both male and female DR3 and female DR15 mice significantly increased BLG-specific IgE production, while robust elevation in BLG-specific IgG1 was observed in sensitized DQ8 mice of both sexes and, to a lesser extent, in DR15 males. Furthermore, BLG-sensitized DR15 mice showed sex-specific behavior changes, with males exhibiting mobility changes and anxiety-like behavior and females showing spatial memory impairment. When splenocytes from transgenic mice were stimulated in vitro with BLG, phenotypes of immune cells were HLA- and sex-specific, further underscoring the influence of HLA-II on immune responses. Our results support that HLA-II alleles influence behavioral responses in addition to immune and physical reactions of food allergy, suggesting that certain HLA-II variants may predispose individuals to food-allergy-associated behavioral changes.

Food allergy and hypersensitivity reactions in children and adults-A review

Adverse reactions after food intake are commonly reported and a cause of concern and anxiety that can lead to a very strict diet. The severity of the reaction can vary depending on the type of food and mechanism, and it is not always easy to disentangle different hypersensitivity diagnoses, which sometimes can exist simultaneously. After a carefully taken medical history, hypersensitivity to food can often be ruled out or suspected. The most common type of allergic reaction is immunoglobulin E (IgE)-mediated food allergy (prevalence 5-10%). Symptoms vary from mild itching, stomach pain, and rash to severe anaphylaxis. The definition of IgE-mediated food allergy is allergic symptoms combined with specific IgE-antibodies, and therefore only IgE-antibodies to suspected allergens should be analyzed. Nowadays, methods of molecular allergology can help with the diagnostic process. The most common allergens are milk and egg in infants, peanut and tree nuts in children, and fish and shellfish in adults. In young children, milk/egg allergy has a good chance to remit, making it important to follow up and reintroduce the food when possible. Other diseases triggered by food are non-IgE-mediated food allergy, for example, eosinophilic esophagitis, celiac disease, food protein-induced enterocolitis syndrome, and hypersensitivity to milk and biogenic amines. Some of the food hypersensitivities dominate in childhood, others are more common in adults. Interesting studies are ongoing regarding the possibilities of treating food hypersensitivity, such as through oral immunotherapy. The purpose of this review was to provide an overview of the most common types of food hypersensitivity reactions.

Study on the relationship between intrapartum group B streptococcus prophylaxis and food allergy in children

OBJECTIVE

To investigate the associations between intrapartum antibiotic prophylaxis of group B streptococcus (GBS) in pregnant women and the risk of food allergy in Chinese children.

DESIGN

Retrospective cohort study of 2,909 mother-child pairs.

SETTING

Taixing People's Hospital in Eastern China.

PARTICIPANTS

Term infants born 2018-2019, followed longitudinally from birth to 3 years.

EXPOSURES

The GBS-IAP was defined as therapy with intravenous penicillin G or ampicillin or cefazolin ≥4 h prior to delivery to the mother. Reference infants were defined as born without or with other intrapartum antibiotic exposure.

METHODS

To investigate the incidence information of food allergy in children aged 18 months and three years old. Kaplan-Meier survival analysis and log-rank tests were used to evaluate the cumulative incidence in the group with GBS-IAP and the group without GBS-IAP. Cox proportional hazards models were conducted to determine the univariate and multivariate association between maternal GBS-IAP and incident food allergy after various covariates were adjusted.

RESULTS

The cumulative incidence of food allergy in the group with GBS-IAP was higher than that in the group without GBS-IAP in children under 18 months old (8.1% vs. 4.5%, P = 0.005, log-rank test), but no significant differences were observed in children under three years old (9.2% vs. 7.0%, P = 0.146, log-rank test). The univariate cox proportional hazards model in children under 18 months old revealed that children in the GBS-IAP group had faster food allergy development when compared with children in the group without GBS-IAP (HR.: 1.887,95% CI: 1.207-2.950, P = 0.005), so was the multivariate model (HR.: 1.906,95% CI: 1.158-3.137, P = 0.011). However, both univariate (HR: 1.343, 95% CI: 0.891∼2.026, P = 0.159) and multivariate (HR: 1.253, 95%CI: 0.796∼1.972, P = 0.329) cox proportional hazards model in children under three years old showed no significant differences between children in the group with GBS-IAP and group without GBS-IAP.

CONCLUSION

Intrapartum antibiotic prophylaxis of group B streptococcus may increase the cumulative incidence and risk of food allergy in children under 18 months old, but it had no significant effect on children under three years old.

Evaluation and Management of Food Allergies in the Emergency Department

Food allergies are a common and serious cause of illness, accounting for an increasing number of emergency department visits annually. Although definite diagnosis lays outside of an emergency department visit, the clinical management of the most serious food allergies highlights emergency care. The staple of acute care remains epinephrine in association with antihistamines and steroids. The greatest threat remains undertreatment for this group of disorders and underutilization of epinephrine. Those who have been treated for a food allergy need a follow-up allergist evaluation, guidance of food avoidance, and avoidance of foods with cross-sensitivities as well as ready access to epinephrine.

Enzymatic crosslinking and food allergenicity: A comprehensive review

Food allergy has become a major global public health concern. In the past decades, enzymatic crosslinking technique has been employed to mitigate the immunoreactivity of food allergens. It is an emerging non-thermal technique that can serve as a great alternative to conventional food processing approaches in developing hypoallergenic food products, owing to their benefits of high specificity and selectivity. Enzymatic crosslinking via tyrosinase (TYR), laccase (LAC), peroxidase (PO), and transglutaminase (TG) modifies the structural and biochemical properties of food allergens that subsequently cause denaturation and masking of the antigenic epitopes. LAC, TYR, and PO catalyze the oxidation of tyrosine side chains to initiate protein crosslinking, while TG initiates isopeptide bonding between lysine and glutamine residues. Enzymatic treatment produces a high molecular weight crosslinked polymer with reduced immunoreactivity and IgE-binding potential. Crosslinked allergens further inhibit mast cell degranulation due to the lower immunostimulatory potential that assists in the equilibration of T-helper (Th)1/Th2 immunobalance. This review provides an updated overview of the studies carried out in the last decade on the potential application of enzymatic crosslinking for mitigating food allergenicity that can be of importance in the context of developing hypoallergenic/non-allergenic food products.

Selenium Modulates the Allergic Response to Whey Protein in a Mouse Model for Cow's Milk Allergy

Cow's milk allergy is a common food allergy in infants, and is associated with an increased risk of developing other allergic diseases. Dietary selenium (Se), one of the essential micronutrients for humans and animals, is an important bioelement which can influence both innate and adaptive immune responses. However, the effects of Se on food allergy are still largely unknown. In the current study it was investigated whether dietary Se supplementation can inhibit whey-induced food allergy in an animal research model. Three-week-old female C3H/HeOuJ mice were intragastrically sensitized with whey protein and cholera toxin and randomly assigned to receive a control, low, medium or high Se diet. Acute allergic symptoms, allergen specific immunoglobulin (Ig) E levels and mast cell degranulation were determined upon whey challenge. Body temperature was significantly higher in mice that received the medium Se diet 60 min after the oral challenge with whey compared to the positive control group, which is indicative of impaired anaphylaxis. This was accompanied by reductions in antigen-specific immunoglobulins and reduced levels of mouse mast cell protease-1 (mMCP-1). This study demonstrates that oral Se supplementation may modulate allergic responses to whey by decreasing specific antibody responses and mMCP-1 release.

A systematic review of infant feeding food allergy prevention guidelines - can we AGREE?

Food allergy is a significant issue worldwide, particularly in Westernised countries. There is no clear explanation why food allergy appears to have increased so rapidly in recent years, particularly in young children, hence ongoing research to identify effective primary prevention strategies. Food allergy prevention guidelines for health professionals have been developed based on existing clinical trial evidence for effective translation and implementation. As these guidelines underpin clinical practice, it is important to ensure robust processes of development. We conducted a systematic review to identify food allergy prevention guidelines for health professional use; to compare the recommendations made by the identified guideline documents; and to assess the quality of the identified guideline documents. We searched Medline, EMBASE, CINAHL, Scopus, Global Health and Guidelines International Network for the period 1990 to 13 August 2019, to identify articles referring to English-language food allergy prevention guidelines or the guidelines themselves. A grey literature search of Google Scholar and reference checking was also undertaken. The guidelines were compared for recommendation similarities and differences. An Appraisal Guidelines for Research and Evaluation (AGREE II) appraisal was undertaken to assess guideline quality. The electronic database search yielded 1121 publications and reference checking identified an additional 16 publications. After title, abstract and full text screening, data extraction was undertaken on 156 publications and with additional reference checking, 28 food allergy prevention guidelines and advice documents were identified. Comparison of the recommendations within the guidelines and advice documents indicated the greatest variation in recommendations related to exclusive breastfeeding and timing of solid food introduction. Eight of the 10 guidelines and none of the 18 advice documents met the quality threshold set by the reviewers. Overall, documents specifically termed "guidelines" scored better than advice documents when assessed using the AGREE II tool. Variation in recommendations may create confusion for health professionals and result in inconsistent advice being provided to parents, and less translation of the evidence into actual food allergy reduction in the population. Appraisal using the AGREE II tool identified that there is considerable room for improvement in the development of guidelines and advice documents for food allergy prevention. The AGREE II appraisal identified common areas of poorer quality development and/or documentation of processes to inform future guideline development. Based on this study, we recommend the use of validated guideline development tools, to direct food allergy prevention guideline review or development. Use of the AGREE II tool, to direct the review and development of guidelines, is very likely to improve guideline quality.

Addressing the social needs of individuals with food allergy and celiac disease during COVID-19: A new practice model for sustained social care

COVID-19 has led to high rates of food insecurity. Food insecure patients with food allergy and celiac disease are especially vulnerable during the pandemic when foods become limited. This paper describes a practice innovation implemented by a community-based organization, Food Equality Initiative (FEI), whose mission is improving health and ending hunger among individuals with food allergy and celiac disease. FEI responded to the pandemic by converting their in-person pantries to a contactless delivery of safe foods. The practice innovation is discussed in relation to three system-level elements necessary to sustain the integration of social care into the delivery of healthcare.

IgE-mediated food allergy throughout life

Food allergy (FA) has become an increasing problem throughout the world. Over the last 2 decades, the frequency of FA has increased in both children and adults. The prevalence differs according to the research methodology, age, and geographic regions, ranging between 2.0% and 10.0%. The most common form of FA is immunoglobulin E (IgE)-mediated FA. In this form, patients may present with life-threatening conditions, such as anaphylaxis, or milder conditions, such as urticaria, angioedema, sneezing, and nausea alone. The gold standard in the diagnosis of FA is oral provocation tests. Epidermal skin prick tests and specific IgE measurements, as well as component-resolved diagnostic techniques are helpful in the diagnosis and follow-up of patients. In this review, the epidemiology, diagnosis, follow-up, and prognosis of IgE-mediated FA in children and adults were discussed and some specific forms of FA, such as pollen FA syndrome, alpha-gal allergy, and food-dependent exercise-induced anaphylaxis were explained.

Piper nigrum extract attenuates food allergy by decreasing Th2 cell response and regulating the Th17/Treg balance

Piper nigrum is extensively utilized because of its antioxidation, antiallergic, antitumor, antiinflammatory, antidiarrhea, and gastrointestinal protection. We attempted to indicate whether the Piper nigrum extract (PNE) could alleviate ovalbumin (OVA)-induced food allergy, and to explore its potential mechanism. An OVA-induced food allergy mouse model was established, and different concentrations of PNE were administrated. Symptoms of food allergy, levels of immunoglobulin E (IgE), mucosal mast cell protease-1 (mMCP-1), and intestine pathological changes were assessed. Additionally, the expressions of T helper (Th) 2, Th17 and regulatory T (Treg)-associated cytokines and the proportion of Th17 and Treg cells in CD4⁺ T cells were measured. We found PNE attenuated symptoms of food allergy and decreased the levels of IgE and mMCP-1. In PNE group, the infiltration degree of inflammatory cells was ameliorated and the villi of small intestine were more complete. Moreover, the expressions of Th2 and Th17 cell-associated cytokines were down-regulated by PNE pretreatment, while the levels of Treg cell-associated cytokines were up-regulated. PNE decreased the number of Th17 cells, while increased the Tregs cells. PNE treatment dose-dependently improved the Th17/Treg balance. PNE plays a protective role in OVA-induced food allergy through inhibiting Th2 cell response and regulating the Th17/Treg balance.

Prevalence and characteristics of peanut allergy in US adults

BACKGROUND

Peanut allergy (PA) is the leading pediatric food allergy and a common cause of anaphylaxis. Little is known, however, on the prevalence and characteristics of PA in the adult population and whether phenotypic differences exist between adult-onset and childhood-onset PA.

OBJECTIVES

This study describes the current US population-level burden of adult PA.

METHODS

A cross-sectional food allergy survey was administered via phone and web in 2015 and 2016, resulting in nationally representative complex-survey weighted data for 40,443 adults. Reported food allergies were considered "convincing" if symptoms to specific allergens were consistent with an IgE-mediated reaction.

RESULTS

The prevalence of current self-reported PA was 2.9% among US adults, with 1.8% having convincing PA. Over 17% of adults with peanut allergy reported onset of their PA in adulthood. In adults with childhood-onset PA, 75.4% reported physician-diagnosed PA, compared with only 58.9% of adult-onset PA. Despite a similar frequency of food allergy-related emergency department visits within the past year (approximately 1 in 5 adults with PA allergy), adults with childhood-onset PA were significantly more likely to have a current epinephrine prescription compared with those with adult-onset PA (56% vs 44% respectively; P = .02) and were more likely to use an epinephrine autoinjector (48% vs 35%, P = .01).

CONCLUSIONS

Approximately 4.6 million US adults have PA-over 800,000 of whom appear to have developed their PA after age 18 years. Further examination of phenotypic differences between childhood-onset and adult-onset PA may improve understanding and management of adult PA.

A systematic review of psychological, clinical and psychosocial correlates of perceived food intolerance

OBJECTIVE

Perceived food intolerance (PFI) is a distressing condition reported by 3% - 35% of individuals, whereas prevalence of food allergy is 0.9%-3%. The present paper aims to systematically review the evidence for psychological, clinical and psychosocial factors associated with PFI in order to advance the current understanding.

METHODS

Articles published from 1970 until October 2020 were identified. Case-control, prospective cohort, cross-sectional and retrospective studies published in English that a) included a subject population of adults over 18 with PFI and b) examined psychological, clinical and/or psychosocial factors of PFI were reviewed against inclusion criteria. Methodological quality was assessed, data extracted, and a narrative synthesis conducted.

RESULTS

Of 2864 abstracts identified, thirty-six articles met inclusion criteria. Evidence consistently found PFI is associated with female sex, and individuals with PFI often report physical health complaints including gastrointestinal and extraintestinal symptoms, and gastrointestinal and atopic conditions. Evidence for an association between psychological factors and PFI was inconsistent, although some suggested increased levels of common mental disorders and distress. Findings regarding psychosocial factors were mixed and sociodemographic data were infrequently collected.

CONCLUSIONS

PFI is associated with female sex and gastrointestinal and extraintestinal complaints. Limited high-quality evidence supports the role of psychological factors associated with PFI. High-quality research using prospective and longitudinal designs with multivariate analyses is needed. Future research should explore modifiable psychological factors as potential targets for intervention and identify clinical and psychosocial risk factors of PFI to aid in formulating a biopsychosocial model of PFI.

Prevalence and Correlates of Food Allergy Among Medicaid-Enrolled United States Children

OBJECTIVE

The objective of this study is to provide a comprehensive epidemiological profile detailing food allergy (FA) prevalence and related correlates among Medicaid-enrolled children.

METHODS

The 2012 Medicaid Analytic eXtract person-level 100% files for 50 states and the District of Columbia were analyzed. The analytic sample of 23,825,160 included all children ages 0 to 19 years as of January 1, 2012 who were continuously enrolled in Medicaid in 2012. The prevalence of FA was measured using International Classification of Diseases, Ninth Revision, Clinical Modification codes and compared with other atopic conditions (atopic dermatitis, allergic rhinitis, and asthma). Logistic regression was used to evaluate child characteristics associated with FA.

RESULTS

The prevalence of FA among Medicaid-enrolled children was less than 1% (0.6%). State-level prevalence ranged from a high of 1.4% in Alaska to a low of 0.2% in Nevada. Race and ethnicity were associated with FA such that Asian, Black, and Pacific Islander/Native Hawaiian children had a higher odds of FA, while Hispanic and Native American children had 15% and 24% lower odds of FA, respectively, compared with White children.

CONCLUSIONS

Compared with estimates of parent-reported, physician-diagnosed FA in the general population, the claims-based prevalence of FA among Medicaid-enrolled children is substantially lower. Racial and ethnic differences are consistent with the general population. The findings signal a need to better understand reasons for these differences including awareness, access to care, and service utilization patterns in this population.

Bovine β-lactoglobulin-induced passive systemic anaphylaxis model using humanized NOG hIL-3/hGM-CSF transgenic mice

Food allergy is a common disease caused by intake of allergen-containing foods, such as milk, eggs, peanuts and wheat. Systemic anaphylaxis is a severe hypersensitive allergic reaction resulting from degranulation of mast cells or basophils after cross-linking of surface high-affinity IgE receptors (Fcε-RI) with allergen-specific IgE and allergens. In this study, we developed a novel human mast cell/basophil-engrafted mouse model that recapitulates systemic anaphylaxis triggered by β-lactoglobulin (BLG), a major allergen found in cow's milk. Human CD34+ hematopoietic stem cells were transferred into NOG (non-Tg) or NOG hIL-3/hGM-CSF transgenic (Tg) mice. After 14-16 weeks, bovine BLG-specific human IgE was intravenously injected into humanized mice, followed by intravenous or oral bovine BLG exposure 1 day later. Body temperature in Tg, but not in non-Tg, mice gradually decreased within 10 min, and 80% of Tg mice died within 1 h by intravenous BLG exposure. Serum histamine levels and anaphylaxis scores in Tg mice were markedly increased compared to non-Tg mice. Furthermore, these allergic symptoms were significantly inhibited by epinephrine treatment of the Tg mice. Therefore, the current NOG hIL-3/hGM-CSF Tg mouse model may be useful for development of novel anaphylaxis drugs for treatment of food allergies and for safety assessment of low-allergenicity extensively hydrolyzed cow's milk whey protein-based infant formulas.

Soluble CD83 suppresses experimental food allergy via regulating aberrant T helper 2 responses

Aberrant T helper-2 (Th2) responses play a critical role in the pathogenesis of allergic diseases. The underlying mechanism is to be further investigated. It is reported that soluble CD83 (sCD83) has immune-regulatory effects. This study aims to investigate the role of sCD83 in the regulation of Th2 polarization. Blood samples were collected from pediatric patients with food allergy (FA). The Th2 response was analyzed by pertinent immunological approaches. An FA murine model was developed to test the role of sCD83 in the regulation of FA response. We found that the serum sCD83 levels were lower in FA patients. A negative correlation was detected between serum sCD83 levels and serum Th2 cytokine levels. The presence of sCD83 suppressed Th2 cell differentiation and antigen-specific Th2 cell activation. sCD83 upregulated the T-bet expression and suppressed the GATA3 expression in CD4+ T cells. Administration of sCD83 suppressed experimental FA. Pediatric FA patients have low serum sCD83 levels. Administration of sCD83 can alleviate experimental FA via suppression of aberrant Th2 polarization.

Food Allergy Insights: A Changing Landscape

The panorama of food allergies (FA) has changed profoundly in recent years. In light of recent advances in knowledge of pathogenetic mechanisms and a greater attention to the multifaceted range of possible clinical manifestations, there is a need for a critical review of past classifications. Changes in nutrition, environment and lifestyles around the world are modifying the global FA epidemiology and new FA phenotypes are also emerging. Furthermore, both biotechnological advances in this field and recent personalized therapies have improved the diagnostic and therapeutic approach to FA. Consequently, both the prevention and clinical management of FA are rapidly changing and new therapeutic strategies are emerging, even revolutionizing the current medical practice. Given the significant increase in the prevalence of FA in recent years, the objective of this review is to provide an updated and complete overview of current knowledge in its etiopathogenesis, diagnostics and therapy, useful not only for a better understanding of this frequent and complex pathology but also for practical guidance in its clinical management.

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.

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.

A Benzenoid 4,7-Dimethoxy-5-Methyl-L, 3-Benzodioxole from Antrodia cinnamomea Attenuates Dendritic Cell-Mediated Th2 Allergic Responses

Dendritic cells (DCs) play a critical role in initiating immune responses; however, DCs also induce Th2-related allergic sensitivities. Thus, DCs become a target for therapeutic design in allergic diseases. In this study, we aim to investigate the anti-allergic effect of pure compounds from a medicinal mushroom Antrodia cinnamomea (Ac) on DC-induced allergic responses. We identified a benzenoid compound 4,7-dimethoxy-5-methyl-l,3-benzodioxole (DMB) which may modulate Th2 polarization in bone marrow-derived DCs (BMDCs) and in a murine food allergy model. DMB effectively reduced the Th2 adjuvant cholera toxin (CT)-induced BMDC maturation and cytokine production. In studying the mechanism, DMB blocked the molecular processes involved in Th2 induction, including cAMP activation, IL-33 production, and IRF4/Tim4 upregulation, in CT-activated BMDCs. Furthermore, DMB treatment attenuated the symptoms, clinical scores, and Th2 responses of CT-induced ovalbumin (OVA)-specific food allergy in mice at sensitization stage. These results indicated that DMB could suppress DC function for Th2 polarization and mitigate allergic responses. Thus, DMB may have potential to be a novel agent for preventing or treating food allergy.

Vasoactive intestinal peptide alleviates food allergy via restoring regulatory B cell functions

The immune regulatory cell dysfunction is associated with many immune diseases including food allergy (FA). This study aims to investigate the role of vasoactive intestinal peptide (VIP) in the maintenance of regulatory B cell (Br cell)'s immune suppressive functions by stabilizing thrombospondin (TSP1) expression. In this study, blood samples were collected from patients with food allergy (FA) and healthy control (HC) subjects. Br cells were isolated from the samples through flow cytometry cell sorting and analyzed by immunological approaches to determine the immune regulatory capacity. We found that the immune suppressive functions of Br cells were impaired in FA patients. The serum VIP levels were associated with the production of immune suppressive function-related mediators (interleukin-10, IL-10) of Br cells in FA patients. VIP counteracted IL-10 mRNA decay in Br cells by up regulating the TSP1 expression. TSP1 inhibited tristetraprolin (TTP) to prevent IL-10 mRNA decay in Br cells. Administration of VIP inhibited FA response through restoration of immune suppressive functions in Br cells. In conclusion, administration of VIP can alleviate FA response through up regulating expression of TSP1 to stabilize IL-10 expression in FA Br cells and recover the immune regulatory functions. The results have translational potential for the treatment of FA and other disorders associated with immune regulatory dysfunction of Br cells.

Oral supplementation with capsaicin reduces oxidative stress and IL-33 on a food allergy murine model

Background

Food allergy is an abnormal immune response to antigens introduced into the body through food. Its prevalence has increased in developed and developing countries. Natural products are traditionally used to alleviate and treat diseases, and diet can play a role in both the prevention and management of food allergy. The effects of capsaicin as an anti-oxidant, anticarcinogenic, and anti-inflammatory in the energy expenditure and suppression of fat accumulation have been demonstrated. This study evaluated the effect of oral supplementation with capsaicin on a food allergy model.

Methods

OVA-sensitized mice received ovalbumin solution, and they were fed with chow supplemented with capsaicin for 7 days. The control group received AIN-93 chow with no supplementation. IgE anti-ova, inflammatory infiltration, oxidative stress and metabolic analysis were performed.

Results

The results showed that capsaicin supplementation is not able to reduce characteristic signs of food allergy, such as production of IgE and weight loss. However, macrophages infiltration and IL-33 in proximal jejunum was reduced in OVA capsaicin group. In addition, hepatic triglycerides and intestinal hydroperoxides were reduced in both capsaicin groups.

Conclusion

Oral supplementation with capsaicin attenuated important factors associated to food allergy such as inflammation and oxidative stress, suggesting better prognosis and evolution of the disease.

Recent Advances in Allergy Research Using Humanized Mice

The prevalence rates of allergic diseases are increasing worldwide, particularly in industrial countries. To date, many mouse models have been generated for allergy research; studies conducted using these models have suggested the importance of cross-talk between immune cells and tissue-resident non-immune cells in the onset of allergic diseases. However, there are several differences between the immune systems of rodents and humans, and human studies are limited. Thus, mice reconstituted with human immune cells are a novel tool for the preclinical evaluation of the efficacy and safety of developing drugs. Genetic technologies for generating humanized mice have improved markedly in recent years. In this review, we will discuss recent progress in allergy research using humanized mice and introduce our recent humanized mouse model of airway inflammation in human immune cells.

Mechanisms of gastrointestinal allergic disorders

Gastrointestinal (GI) allergic disease is an umbrella term used to describe a variety of adverse, food antigen-driven, immune-mediated diseases. Although these diseases vary mechanistically, common elements include a breakdown of immunologic tolerance, a biased type 2 immune response, and an impaired mucosal barrier. These pathways are influenced by diverse factors such as diet, infections, exposure to antibiotics and chemicals, GI microbiome composition, and genetic and epigenetic elements. Early childhood has emerged as a critical period when these factors have a dramatic impact on shaping the immune system and therefore triggering or protecting against the onset of GI allergic diseases. In this Review, we will discuss the latest findings on the molecular and cellular mechanisms that govern GI allergic diseases and how these findings have set the stage for emerging preventative and treatment strategies.

Food allergy: what it is and what it is not?

PURPOSE OF REVIEW

Food allergy is defined as an adverse health effect arising from a specific immune response that occurs reproducibly on exposure to a given food. Food intolerance, certain gastrointestinal or systemic diseases are often confused with or mislabeled as food allergy because of symptomatic similarity and general improvement from food avoidance. The differences between these diseases are crucial.

RECENT FINDINGS

Compared with many food-related diseases that are isolated to gastrointestinal organs, food allergy can affect not only local but the whole immune system and may lead to a life-threatening allergic reaction, known as anaphylaxis. In this review, the differentiation between food allergy, food intolerance, and other comparable diseases is discussed.

SUMMARY

With recent medical advances reflecting on the importance of accurate diagnosis in food hypersensitivity, healthcare providers who are treating food hypersensitivity should familiarize with latest science progress, identify and treat active disease, and refer to appropriate specialists if needed.

Antibiotic Exposure and the Risk of Food Allergy: Evidence in the US Medicaid Pediatric Population

BACKGROUND

Food allergy is a significant public health concern in the United States, especially in the pediatric population. It places substantial clinical and economic burdens on the health care system. Exposure to antibiotics in early childhood is thought to increase the risk of subsequent food allergy.

OBJECTIVE

To examine the impact of exposure to antibiotics early in life on time to development of food allergy.

METHODS

We conducted a population-based matched cohort study using Medicaid data from 28 states. Antibiotic nonusers were matched 1:1 to antibiotic users on date of birth, sex, race, and state. A Cox proportional hazards regression model was used to evaluate the effect of antibiotic exposure on time to development of food allergy. Sensitivity analyses were performed to assess the robustness of study findings.

RESULTS

We matched 500,647 antibiotic nonusers to 500,647 antibiotic users in the Medicaid pediatric population. In the adjusted Cox proportional hazards regression analysis, antibiotic exposure was significantly associated with faster development of food allergy (hazard ratio, 1.40; 95% CI, 1.34-1.45). The magnitude and significance of the association between antibiotic exposure and food allergy did not change in the sensitivity analyses. A significant association between antibiotic exposure and faster development of food allergy was found in 17 of 28 states.

CONCLUSION

Compared with antibiotic nonusers, children with antibiotic prescription had an increased risk of food allergy.

Current insights in allergen immunotherapy

OBJECTIVE

Allergen-specific immunotherapy (AIT) in its subcutaneous and sublingual forms is currently a well-established and experimentally supported treatment for respiratory allergy and hymenoptera venom allergy. There have been advances in its use linked strictly to the advancement in the knowledge of the molecular mechanisms of allergy, the production of well-characterized extracts, and diagnostic techniques. The use of AIT in asthma and the application of new approaches are expanding. We briefly review the advances and concerns in the use of AIT.

DATA SOURCES

PubMed and Scopus.

STUDY SELECTIONS

The most recent and clinically relevant literature was selected and reviewed.

RESULTS

The introduction of high-quality products supported by large dose-finding trials has yielded better defined indications, contraindications, and modalities of use. Some specific products in tablet form have recently been approved in the United States. Sublingual immunotherapy has been found to be effective in asthma, which until recently had been a matter of debate. Another promising therapy is oral and sublingual desensitization for food allergy, for which encouraging results have recently been reported. In the near future, other options will be available, including new routes of administration (intralymphatic and epicutaneous), allergoids, engineered allergens, and peptides. The use of component-resolved diagnosis techniques will further refine and target AIT prescriptions.

CONCLUSION

This condensed and updated review shows that AIT remains a viable treatment option, especially after the introduction of standardized tablets for some allergens. Food allergy and new administration routes represent a promising expansion.

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.

The interplay of type 2 immunity, helminth infection and the microbiota in regulating metabolism

Type 2 immunity has recently emerged as a critical player in metabolic status, with numerous studies investigating the role of type 2 immune cells within adipose tissue. Metabolic dysfunction is often characterised as a low-grade or chronic inflammatory state within tissues, and type 2 immunity may facilitate a return to metabolic homeostasis. A complex network of type 2 resident cells including M2 macrophages, eosinophils and ILC2s has been identified within adipose tissue. Although the effector cells in this equilibrium have not been clearly identified, any alteration of the type 2 microenvironment resulted in an altered metabolic state. Historically, the type 2 immune response has been associated with helminth infection. The type 2 immune response drives host resistance and plays an important role in promoting tissue repair following the migration of helminth larvae through tissues. Although helminths are largely eradicated in developed countries, infection rates remain high in poor communities within the developing world. Interestingly, there is strong evidence that helminth infection is inversely correlated with autoimmune or inflammatory disorders. Recently, an increasing amount of epidemiological and field studies suggest that it could be the same for obesity and metabolic syndrome. In the current review, we summarise the literature linking type 2 immunity to improved adipose tissue function. We then discuss more recent evidence indicating that helminth infection can provide protection against metabolic syndrome. Lastly, we explore the possible contributions of altered nutrient uptake, adipose tissue function and/or the intestinal microbiota with the ability of helminths to alter metabolic status.

IgG1+ B-cell immunity predates IgE responses in epicutaneous sensitization to foods

BACKGROUND

The generation of IgE-mediated food allergy in humans is silent and only diagnosed upon manifestation of clinical symptoms. While experimental models have been used to investigate some mechanisms of allergic sensitization, the generation of humoral immunity and memory remains to be elucidated. Here, we defined the evolution of allergen-specific B-cell responses during epicutaneous sensitization to foods.

METHODS

Wild-type and genetic knockout animals, and drug or antibody strategies for cell depletion and immunoglobulin signaling blockade were used to investigate epicutaneous sensitization and disease progression; we analyzed allergen-specific germinal centers and IgG1⁺ memory B cells by flow cytometry, evaluated humoral responses, and determined clinical reactivity (anaphylaxis).

RESULTS

Epicutaneous sensitization caused microscopic skin damage, inflammation, and recruitment of activated dendritic cells to the draining lymph nodes. This process generated allergen-specific IgG1⁺ germinal center B cells, serum IgG1, and anaphylaxis that was mediated by the alternative pathway. Whether we used peanut and/or ovalbumin from the egg white for sensitization, the allergen-specific IgG1⁺ memory compartment predominantly exhibited an immature, pro-germinal center phenotype (PDL-2^- CD80^- CD35⁺ CD73⁺ ). Subsequent subclinical exposures to the allergen induced IgE⁺ germinal center B cells, serum IgE, and likely activated the classical pathway of anaphylaxis.

CONCLUSIONS

Our data demonstrate that IgG1⁺ B-cell immunity against food allergens in epicutaneous sensitization precedes the generation of IgE responses. Therefore, the assessment of allergen-specific cellular and humoral IgG1⁺ immunity may help to identify individuals at risk of developing IgE-mediated food allergy and hence provide a window for therapeutic interventions.

Oral and Sublingual Immunotherapy for Treatment of IgE-Mediated Food Allergy

Development of active therapies for IgE-mediated food allergy is a critical action step toward alleviating the adverse medical, psychosocial, and economic burdens on affected patients and families. Significant progress has been observed specifically in the application of single-allergen oral and sublingual immunotherapy for treatment of IgE-mediated food allergy, with emphasis on milk, egg, and peanut as the primary allergens. Oral immunotherapy (OIT) has demonstrated efficacy in promoting immunomodulatory effects that lead to the clinical outcome of desensitization, defined as reduced reactivity while on active OIT, in the majority of treated individuals; however, achievement of sustained unresponsiveness following cessation of therapy has been observed in a smaller subset of treated subjects. The potential therapeutic benefits of OIT must be carefully considered in light of the significant potential for adverse events ranging from self-limited or easily treated oropharyngeal, respiratory or gastrointestinal symptoms, to persistent abdominal complaints that lead to cessation of therapy in an estimated 10-15% of treated individuals. To date, the majority of studies have focused on single-allergen OIT approaches; however, multi-allergen OIT has shown promise in initial trials and is the subject of ongoing investigation to address the complex needs of multi-food allergic individuals. Sublingual immunotherapy (SLIT) has been utilized for the treatment of food allergy and pollen-food allergy syndrome, demonstrating moderate efficacy, a favorable safety profile and variable tolerability, with oropharyngeal symptoms most commonly observed. Although studies directly comparing OIT and SLIT are limited, in general, the favorable safety profile associated with SLIT comes at the expense of reduced efficacy, while the more robust clinical effects observed with OIT come at the risk of potentially intolerable, treatment-limiting side effects. Future investigation to address specific knowledge gaps including optimal dose, duration, age of initiation, maintenance schedule, mechanisms, predictors of risk and therapeutic response will be important to maximize efficacy, minimize risk and develop personalized, effective approaches to targeting food allergy.