Distribution of peanut protein in the home environment

Follow-up to Adolescence after Early Peanut Introduction for Allergy Prevention

BACKGROUND

A randomized trial demonstrated consumption of peanut from infancy to age 5 years prevented the development of peanut allergy. An extension of that trial demonstrated the effect persisted after 1 year of peanut avoidance. This follow-up trial examined the durability of peanut tolerance at age 144 months after years of ad libitum peanut consumption.

METHODS

Participants from a randomized peanut consumption trial were assessed for peanut allergy following an extended period of eating or avoiding peanuts as desired. The primary end point was the rate of peanut allergy at age 144 months.

RESULTS

We enrolled 508 of the original 640 participants (79.4%); 497 had complete primary end point data. At age 144 months, peanut allergy remained significantly more prevalent in participants in the original peanut avoidance group than in the original peanut consumption group (15.4% [38 of 246 participants] vs. 4.4% [11 of 251 participants]; P<0.001). Participants in both groups reported avoiding peanuts for prolonged periods of time between 72 and 144 months. Participants at 144 months in the peanut consumption group had levels of Ara h2-specific immunoglobulin E (a peanut allergen associated with anaphylaxis) of 0.03 ± 3.42 kU/l and levels of peanut-specific immunoglobulin G4 of 535.5 ± 4.98 μg/l, whereas participants in the peanut avoidance group had levels of Ara h2-specific immunoglobulin E of 0.06 ± 11.21 kU/l and levels of peanut-specific immunoglobulin G4 of 209.3 ± 3.84 μg/l. Adverse events were uncommon, and the majority were related to the food challenge.

CONCLUSIONS

Peanut consumption, starting in infancy and continuing to age 5 years, provided lasting tolerance to peanut into adolescence irrespective of subsequent peanut consumption, demonstrating that long-term prevention and tolerance can be achieved in food allergy. (Funded by the National Institute of Allergy and Infectious Diseases and others; ITN070AD, ClinicalTrials.gov number, NCT03546413.).

[The impact of today's environment on allergies: can we take action?]

Allergic diseases have risen sharply in recent decades. After some epidemiological data, we take a look at the various hypotheses explaining this allergy "epidemic". Changes in our environment, such as pollution, are a source of climate change and an increase in allergic diseases through inflammation of epithelial barriers. Allergy prevention, a public health emergency, relies on environmental actions at both individual and collective levels.

Experiences and perceptions of people with celiac disease, food allergies and food intolerance when dining out

Introduction

Eating out is a common practice in modern society. Celiac disease (CeD) and food allergy (FA) are among the most common conditions responsible for adverse reactions to food. Despite their different origins, both require treatment with restrictive diets (avoidance of gluten and/or specific allergens) and this results posing similar challenges when eating out. Our objective was to learn about the experiences/perceptions of consumers with CeD and FA when dining out, as well as the challenges they face in food service environments.

Methods

An ad hoc questionnaire was used to record consumer perceptions, food service characteristics and resulting adverse reactions.

Results

377 individuals living in Santiago, Chile, provided complete information and were analyzed (160 CeD, 105 FA). 301 participants (79.8%) declared eating out, 33.6% reported experiencing an adverse reaction at least once while eating out. 94.4% of the 377 participants believed that the serving staff had little or no knowledge about his/her condition. Consumers reporting symptoms as severe adverse reactions were more common among celiac than allergic patients (p < 0.001).

Discussion

The study showed no significant differences based on consumer-related characteristics (p:NS). The consequences of eating out did not vary based on individual's data, including diagnosis, age, frequency of eating out, adverse reactions experienced, or intensity. These findings suggest that the most important determinants of risk associated with eating out are characteristics of the food service, like availability of information, staff training, and establishment's facilities like equipment available, exclusive utensils for customers with special dietary needs and kitchen and bathrooms organization.

Anaphylaxis: A 2023 practice parameter update

This practice parameter update focuses on 7 areas in which there are new evidence and new recommendations. Diagnostic criteria for anaphylaxis have been revised, and patterns of anaphylaxis are defined. Measurement of serum tryptase is important for diagnosis of anaphylaxis and to identify underlying mast cell disorders. In infants and toddlers, age-specific symptoms may differ from older children and adults, patient age is not correlated with reaction severity, and anaphylaxis is unlikely to be the initial reaction to an allergen on first exposure. Different community settings for anaphylaxis require specific measures for prevention and treatment of anaphylaxis. Optimal prescribing and use of epinephrine autoinjector devices require specific counseling and training of patients and caregivers, including when and how to administer the epinephrine autoinjector and whether and when to call 911. If epinephrine is used promptly, immediate activation of emergency medical services may not be required if the patient experiences a prompt, complete, and durable response. For most medical indications, the risk of stopping or changing beta-blocker or angiotensin-converting enzyme inhibitor medication may exceed the risk of more severe anaphylaxis if the medication is continued, especially in patients with insect sting anaphylaxis. Evaluation for mastocytosis, including a bone marrow biopsy, should be considered for adult patients with severe insect sting anaphylaxis or recurrent idiopathic anaphylaxis. After perioperative anaphylaxis, repeat anesthesia may proceed in the context of shared decision-making and based on the history and results of diagnostic evaluation with skin tests or in vitro tests when available, and supervised challenge when necessary.

[Oral allergy syndrome (OAS)]

The pollen-food allergy syndrome, also known as oral allergy syndrome, is characterized by local reactions in the mouth and throat after consuming certain raw plant foods in individuals sensitized to pollen from grass, weeds, and trees. Birch-apple is the prototype of this syndrome, with apple, pear, and plum being the most commonly associated foods. Symptoms are usually limited to the oral cavity but can include systemic reactions, including anaphylaxis. Sensitization to pollen allergens, such as lipid transfer proteins, profilin, and PR-10 proteins, triggers this syndrome. Its prevalence varies by geographic region and the predominant pollen type, affecting between 30% and 60% of food allergies. Diagnosis involves a clinical history, skin tests, and, in ambiguous cases, double-blind, placebo-controlled oral food challenges. Treatment primarily involves avoiding trigger foods.

[Food allergy and environmental contamination]

The interaction between genetic potential and the environment, especially increased urbanization and inadequate waste management, contributes to the manifestation of allergic diseases. Pediatric patients are the most vulnerable, due to the immaturity of the respiratory and immune systems. Prenatal and postnatal exposure to air pollutants, both indoors and outdoors, accelerates or aggravates morbidity and mortality from allergic diseases. The "exposome," which encompasses all environmental exposures throughout life, influences health. Biological and chemical attacks alter the epithelial barrier, triggering inflammatory responses and favoring allergic diseases, such as food allergies. The uncontrolled use of toxic fuels, particulate matter, detergents and other factors contribute to the continuous deterioration of the intestinal epithelial barrier, increasing the risk of allergic diseases. It is important to take urgent action to address these issues and protect the health of the planet.

A single priming event prevents oral tolerance to peanut

BACKGROUND

Indoor dust (ID) is a source of peanut proteins and immunostimulatory adjuvants (e.g. LPS) that can promote airway sensitization to peanut. We aimed to determine whether a single airway exposure to peanut plus adjuvant is sufficient to prevent oral tolerance.

METHODS

To determine the effect of a single priming event, C57BL/6J mice were exposed once to peanut plus adjuvant through the airway, followed by either airway or low-dose oral exposure to peanut, and assessed for peanut allergy. Oral tolerance was investigated by feeding high-dose peanut followed by airway sensitization. To determine whether a single priming could prevent oral tolerance, the high-dose peanut regimen was applied after a single airway exposure to peanut plus adjuvant. Peanut-specific IgE and IgG1 were quantified, and mice were challenged to peanut to assess allergy. Peanut-specific CD4+ memory T cells (CD4+ TCRβ+ CD44hi CD154+ ) were quantified in mediastinal lymph nodes following airway priming.

RESULTS

Mice co-exposed to peanut with LPS or ID through the airway were primed to develop peanut allergy after subsequent low-dose oral or airway exposures to peanut. Oral tolerance was induced in mice fed high-dose peanut prior to airway sensitization. In contrast, mice fed high-dose peanut following a single airway exposure to peanut plus adjuvant led to allergy. Peanut-specific CD4+ memory T cells were detected as early as 7 days after the single airway priming with peanut plus adjuvant, however, delaying peanut feeding even 1 day following priming led to allergy, whereas peanut feeding the same day as priming led to tolerance.

CONCLUSIONS

A single airway exposure to peanut plus adjuvant is sufficient to prime the immune system to develop allergy following subsequent high-dose oral exposure. These results highlight the importance of introducing peanut as early as possible to prevent sensitization through a non-oral priming event.

Environmental Exposure to Foods as a Risk Factor for Food Allergy

PURPOSE OF REVIEW

Many factors have been reported to contribute to the development of food allergy. Here, we summarize the role of environmental exposure to foods as a major risk factor for developing food allergy.

RECENT FINDINGS

Peanut proteins are detectable and biologically active in household environments, where infants spend a majority of their time, providing an environmental source of allergen exposure. Recent evidence from clinical studies and mouse models suggests both the airway and skin are routes of exposure that lead to peanut sensitization. Environmental exposure to peanut has been clearly associated with the development of peanut allergy, although other factors such as genetic predisposition, microbial exposures, and timing of oral feeding of allergens also likely contribute. Future studies should more comprehensively assess the contributions of each of these factors for a variety of food allergens to provide more clear targets for prevention of food allergy.

Indoor aeroallergens from American cockroaches and mites initiate atopic march via cutaneous contact in a murine model

The progression of allergic diseases from atopic dermatitis in childhood to other allergic conditions such as asthma in later life is often referred to as the atopic march. In order to study the relationship between cutaneous sensitization by aeroallergen and atopic march, we established a mouse model to test the hypothesis using American cockroaches and house dust mites as the model allergens. Mice were sensitized via skin with native cockroach extract (CraA) or recombinant Per a 2 and Der p 2 proteins without adjuvant. Each mouse was subjected to a total of three 1-week patching sensitizations with a 2-week interval in between each application. The resulting immunological variables in sera, scratching behavior, airway hyperresponsiveness (AHR), and pathology of skin lesions and nasal mucosa were evaluated. In mice, application of CraA, rPer a 2, and rDer p 2 aeroallergens through skin patching induced significantly high levels of both total IgE and specific IgEs. The epicutaneous sensitization after a subsequent allergen challenge showed a significant increase in scratch bouts, AHR, epidermal thickness, and eosinophil counts in the skin compared with the control mice. In addition, stimulation of murine splenocytes with allergens increased higher levels of Th2 cytokines, anti-inflammatory cytokines, and chemokines excretion. Our study provides evidence supporting that epicutaneous sensitization to aeroallergens also led to nasal and airway symptoms comparable to atopic march as described in humans. We hope this new allergy model will be useful in the development of new preventive and therapeutic strategies aimed at stopping the atopic march.

Impact of the exposome on food allergy development

PURPOSE OF REVIEW

The increasing global prevalence of food allergy indicates that environmental exposures are likely contributing to food allergy development. This review summarizes recent studies on how specific factors within the external exposome may impact the development of food allergy.

RECENT FINDINGS

There is strong evidence that nonoral exposure to food allergens within the living environment is a risk factor for food sensitization and food allergy. The role of air pollution in food allergy development remains unclear, as cohort studies have not found consistent relationships between air pollutant exposure and food sensitization. Early-life microbial exposures linked to a rural lifestyle are likely protective against food allergy development, possibly through alteration of the infant microbiome. In contrast, factors associated with urbanization and decreased exposure to microbes may contribute to food allergy development. Recent studies on the role of residential greenness in food allergy development suggest either no relationship or a possible increased risk for food allergy.

SUMMARY

The external exposome comprises a number of exposures that can modify food allergy risk. Improved understanding of how complex environmental exposures interact with genetic factors will be necessary for developing effective interventions aimed at preventing food allergy development in children.

Peanut lipids influence the response of bronchial epithelial cells to the peanut allergens Ara h 1 and Ara h 2 by decreasing barrier permeability

Background: Peanut-allergic individuals react upon their first known ingestion of peanuts, suggesting sensitization occurs through non-oral exposure. Increasing evidence suggests that the respiratory tract is a probable site for sensitization to environmental peanuts. However, the response of the bronchial epithelium to peanut allergens has never been explored. Furthermore, food matrix-derived lipids play an important role in allergic sensitization. Objective: To contribute to a better understanding of the mechanisms of allergic sensitization to peanuts via inhalation, by exploring the direct effect of the major peanut allergens Ara h 1 and Ara h 2 and peanut lipids on bronchial epithelial cells. Methods: Polarized monolayers of the bronchial epithelial cell line 16HBE14o- were stimulated apically with peanut allergens and/or peanut lipids (PNL). Barrier integrity, transport of allergens across the monolayers, and release of mediators were monitored. Results: Ara h 1 and Ara h 2 impacted the barrier integrity of the 16HBE14o- bronchial epithelial cells and crossed the epithelial barrier. Ara h 1 also induced the release of pro-inflammatory mediators. PNL improved the barrier function of the cell monolayers, decreased paracellular permeability and reduced the amount of allergens crossing the epithelial layer. Conclusion: Our study provides evidence of the transport of Ara h 1 and Ara h 2 across the airway epithelium, of the induction of a pro-inflammatory milieu, and identifies an important role for PNL in controlling the amount of allergens that can cross the epithelial barrier. These, all together, contribute to a better understanding of the effects of peanuts exposure on the respiratory tract.

A Mouse Model of the “LEAP” Study Reveals a Role for CTLA-4 in Preventing Peanut Allergy Induced by Environmental Peanut Exposure

BACKGROUND

A human study, Learning Early About Peanut Allergy (LEAP), showed that early introduction of peanut products decreases the prevalence of peanut allergy among children. However, the immunologic mechanisms mediating the protective effects of consuming peanut products are not well understood.

OBJECTIVE

The objective was to develop a mouse model that simulates the LEAP study and investigate the underlying mechanisms for the study observations.

METHODS

Adult naive BALB/c mice were fed a commercial peanut butter product (Skippy) or buffer control and concomitantly exposed to peanut flour through the airway or skin to mimic environmental exposure. The animals were analyzed for anaphylactic reaction and by molecular and immunologic approaches.

RESULTS

After exposure to peanut flour through the airway or skin, naive mice developed peanut allergy, as demonstrated by acute and systemic anaphylaxis in response to challenge with peanut extract. Ingestion of Skippy, however, nearly abolished the increase in peanut-specific IgE and IgG and protected animals from developing anaphylaxis. Skippy-fed mice showed reduced numbers of T follicular helper (Tfh) cells and germinal center B cells in their draining lymph nodes, and single-cell RNA sequencing revealed a CD4⁺ T-cell population expressing cytotoxic T lymphocyte-associated protein 4 (CTLA-4) in these animals. Critically, blocking CTLA-4 with antibody increased levels of peanut-specific antibodies and reversed the protective effects of Skippy.

CONCLUSION

Ingestion of a peanut product protects mice from peanut allergy induced by environmental exposure to peanuts, and the CTLA-4 pathway, which regulates Tfh cell responses, likely plays a pivotal role in this protection.

Route of Sensitization to Peanut Influences Immune Cell Recruitment at Various Mucosal Sites in Mouse: An Integrative Analysis

Symptom occurrence at the first ingestion suggests that food allergy may result from earlier sensitization via non-oral routes. We aimed to characterize the cellular populations recruited at various mucosal and immune sites after experimental sensitization though different routes. BALB/cJ mice were exposed to a major allergenic food (peanut) mixed with cholera toxin via the intra-gastric (i.g.), respiratory, cutaneous, or intra-peritoneal (i.p.) route. We assessed sensitization and elicitation of the allergic reaction and frequencies of T cells, innate lymphoid cells (ILC), and inflammatory and dendritic cells (DC) in broncho-alveolar lavages (BAL), lungs, skin, intestine, and various lymph nodes. All cellular data were analyzed through non-supervised and supervised uni/multivariate analysis. All exposure routes, except cutaneous, induced sensitization, but intestinal allergy was induced only in i.g.- and i.p.-exposed mice. Multivariate analysis of all cellular constituents did not discriminate i.g. from control mice. Conversely, respiratory-sensitized mice constituted a distinct cluster, characterized by high local inflammation and immune cells recruitment. Those mice also evidenced changes in ILC frequencies at distant site (intestine). Despite absence of sensitization, cutaneous-exposed mice evidenced comparable changes, albeit less intense. Our study highlights that the initial route of sensitization to a food allergen influences the nature of the immune responses at various mucosal sites. Interconnections of mucosal immune systems may participate in the complexity of clinical manifestations as well as in the atopic march.

Association of egg protein levels in dust with allergy status and related factors

BACKGROUND

Levels of peanut protein in dust have been reported to be associated with sensitization and allergy to it, so controlling food protein in dust may help prevent food allergy. However, studies of factors associated with egg protein levels in dust are scarce. This study aimed to determine the factors contributing to egg protein levels in dust.

METHODS

This cross-sectional study included 159 participants in the Sub-Cohort Study of the Japan Environment and Children's Study in Yamanashi Prefecture at a 6 year follow up. House dust at 6 years was collected and egg protein concentrations were measured for whole egg protein. Household factors, including the maternal frequency of egg consumption, were assessed by questionnaires. A linear regression model was used to analyze the effect of household environmental factors on egg protein in dust.

RESULTS

In multivariate analysis, frequent maternal egg consumption (≥5 times a week) was associated with higher egg protein concentrations in house dust (β = 0.96, P = 0.01). The egg protein load was significantly associated with a higher number of cohabitants (≥5, β = 0.85, P = 0.02) in addition to frequent maternal egg consumption. Among the participants, 140 (88.1%) had no egg allergy, 15 (9.4%) were egg tolerant, and 4 (2.5%) had an egg allergy at 6 years old. There was no significant association between the current egg allergy status and egg protein concentrations in dust.

CONCLUSIONS

The frequency of maternal egg consumption and the number of inhabitants are contributing factors to egg protein levels in dust.

Children of Asian ethnicity in Australia have higher risk of food allergy and early-onset eczema than those in Singapore

BACKGROUND

In Western countries, Asian children have higher food allergy risk than Caucasian children. The early-life environmental exposures for this discrepancy are unclear. We aimed to compare prevalence of food allergy and associated risk factors between Asian children in Singapore and Australia.

METHODS

We studied children in the Growing Up in Singapore Towards healthy Outcomes (GUSTO) birth cohort (n = 878) and children of Asian ancestry in the HealthNuts cohort (n = 314). Food allergy was defined as a positive SPT ≥3 mm to egg or peanut AND either a convincing history of IgE-mediated reaction at 18 months (GUSTO) or a positive oral food challenge at 14-18 months (HealthNuts). Eczema was defined as parent-reported doctor diagnosis.

RESULTS

Food allergy prevalence was 1.1% in Singapore and 15.0% in Australia (P<0.001). Egg introduction was more often delayed (>10 months) in Singapore (63.5%) than Australia (16.3%; P<0.001). Prevalence of early-onset eczema (<6 months) was lower in Singapore (8.4%) than Australia (30.5%) (P<0.001). Children with early-onset eczema were more likely to have food allergy than those without eczema in Australia [aOR 5.11 (2.34-11.14); P<0.001] and Singapore [aOR4.00 (0.62-25.8); P = 0.145].

CONCLUSIONS

Among Asian children, prevalence of early-onset eczema and food allergy was higher in Australia than Singapore. Further research with larger sample sizes and harmonized definitions of food allergy between cohorts is required to confirm and extend these findings. Research on environmental factors influencing eczema onset in Australia and Singapore may aid understanding of food allergy pathogenesis in different parts of the world.

Detection of Food Allergens in School and Home Environments of Elementary Students

BACKGROUND

Little is known about environmental food allergen exposure on school surfaces.

OBJECTIVE

To compare the distribution of major food allergens in floor dust and table wipe samples from elementary schools and dust samples from students' homes.

METHODS

In this substudy of the School Inner-City Asthma Study-II, 103 table wipe samples and 98 floor dust samples from cafeterias and classrooms in 18 elementary schools were analyzed for milk, peanut, cashew, hazelnut, and egg using a multiplex array. Home kitchen floor and bed dust samples from 90 students were also analyzed.

RESULTS

Food allergens were detectable in schools, but at significantly lower levels than in homes (P < .001). In schools, milk and peanut were detected in all table wipe samples; milk and egg were detected in all floor dust samples. Cafeteria table wipe samples contained significantly higher levels of milk, peanut, hazelnut, and egg, compared with classrooms. Cafeteria floor dust samples contained higher levels milk than classrooms. Peanut-restrictive policies did not consistently reduce environmental peanut exposure in schools. Peanut allergen was lower in dust from homes of students with peanut allergy (n = 5) compared with those without peanut allergy (n = 85) (P < .001). Reassuringly, peanut allergen in the schools of peanut-allergic students was not significantly different than in their homes.

CONCLUSION

Food allergens were readily detectable on tables and floors in elementary schools, but at levels lower than in students' homes. For peanut-allergic students, the levels of detectable peanut in their schools were not higher than their homes. The low levels of detectable food allergens in school environments are unlikely to result in severe allergic reactions.

The airway as a route of sensitization to peanut: An update to the dual allergen exposure hypothesis

Food allergies have increased at an alarming rate over the past 2 decades, indicating that environmental factors are driving disease progression. It has been postulated that sensitization to foods, in particular, peanut, occurs through impaired skin. Peanut allergens have been quantified in household dust and may be the culprit source. Indeed, T_H2 cell-skewing innate cytokines can be driven by application of food antigens on both intact and impaired skin of mice, resulting in antigen-specific IgE production and anaphylaxis following allergen exposure. However, allergy induction through the skin can be prevented by induction of oral tolerance before skin exposure. These observations led to the dual allergen exposure hypothesis, according to which oral exposure to food antigens leads to tolerance and antigen exposure on impaired skin leads to allergy. Here, we propose the airway as an alternative route of sensitization in the dual allergen exposure hypothesis that leads to food allergy. Specifically, we will provide evidence from mouse models and human cell-based studies that together implicate the airway as a plausible route of sensitization.

Allergic Food Sensitization and Disease Manifestation in the Fetus and Infant: A Perspective

Even though allergic disease is identified in the first year of life, it is often in a less forward fashion, with elements of a wait and see approach. If the infant does not have an anaphylactic food reaction, other less dramatic allergic phenomenon is often under-emphasized, waiting for additional concerns. We approached this with a conception to first conduct birthday surveys, attempting to link intrauterine and peri-birth circumstances to affect better allergy recognition in young infants.

Managing Food Allergy in Schools During the COVID-19 Pandemic

In the wake of the COVID-19 pandemic and massive disruptions to daily life in the spring of 2020, in May 2020, the Centers for Disease Control (CDC) released guidance recommendations for schools regarding how to have students attend while adhering to principles of how to reduce the risk of contracting SARS-CoV-2. As part of physical distancing measures, the CDC is recommending that schools who traditionally have had students eat in a cafeteria or common large space instead have children eat their lunch or other meals in the classroom at already physically distanced desks. This has sparked concern for the safety of food-allergic children attending school, and some question of how the new CDC recommendations can coexist with recommendations in the 2013 CDC Voluntary Guidelines on Managing Food Allergy in Schools as well as accommodations that students may be afforded through disability law that may have previously prohibited eating in the classroom. This expert consensus explores the issues related to evidence-based management of food allergy at school, the issues of managing the health of children attending school that are acutely posed by the constraints of an infectious pandemic, and how to harmonize these needs so that all children can attend school with minimal risk from both an infectious and allergic standpoint.

Management of Peanut Allergy

Peanut allergy is a growing public health concern in westernized countries. Peanut allergy is characterized as an often severe and lifelong allergy, which can have detrimental effects on quality of life and trigger anxiety. Although multiple therapeutic options are emerging, the focus of current management strategies is strict peanut avoidance and carriage of self-injectable epinephrine. The greatest risk of reacting to peanut comes from direct ingestion, whereas casual skin contact or airborne exposure is highly unlikely to provoke significant symptoms. Patients and families must be educated about how to best execute strict peanut avoidance through careful label reading as well as how to understand and address likely and unlikely risk with regard to peanut exposure in public, in particular when dining outside of the home and for children attending school or child care. This review discusses the risk of exposure in public such as at school or on an airplane and how such risk can be abated, situations and scenarios when dining out of the house that may pose more risks than others, the essentials of US and EU label reading laws with particular emphasis on precautionary labeling and the risk implied by such, quality of life and psychosocial issues that may affect the peanut allergic individual and family, and a discussion of how risk may differ and evolve based on the patient's age.

Allergen Removal and Transfer with Wiping and Cleaning Methods Used in Retail and Food Service Establishments

ABSTRACT

Preventing the transfer of allergens from one food to another via food contact surfaces in retail food environments is an important aspect of retail food safety. Existing recommendations for wiping and cleaning food contact surfaces is mainly focused on preventing microorganisms, such as bacteria and viruses, from contaminating foods. The effectiveness of these wiping and cleaning recommendations for preventing the transfer of food allergens in retail and food service establishments remains unclear. This project investigated (i) allergen removal from surfaces by wiping with paper wipes, terry cloth, and alcohol quaternary ammonium chloride (quat) sanitizing wipes; (ii) cleaning of allergen-contaminated surfaces by using a wash-rinse-sanitize-air dry procedure; and (iii) allergen transfer from contaminated wipes to multiple surfaces. Food contact surfaces (stainless steel, textured plastic, and maple wood) were contaminated with peanut-, milk- and egg-containing foods and subjected to various wiping and cleaning procedures. For transfer experiments, dry paper wipes or wet cloths contaminated with allergenic foods were wiped on four surfaces of the same composition. Allergen-specific lateral flow devices were used to detect the presence of allergen residues on wiped or cleaned surfaces. Although dry wipes and cloths were not effective for removing allergenic foods, terry cloth presoaked in water or sanitizer solution, use of multiple quat wipes, and the wash-rinse-sanitize-air dry procedure were effective in allergen removal from surfaces. Allergens present on dry wipes were transferred to wiped surfaces. In contrast, minimal or no allergen transfer to surfaces was found when allergen-contaminated terry cloth was submerged in sanitizer solution prior to wiping surfaces. The full cleaning method (wash-rinse-sanitize-air dry) and soaking the terry cloth in sanitizer solution prior to wiping were effective at allergen removal and minimizing allergen transfer.

HIGHLIGHTS

The External Exposome and Food Allergy

PURPOSE OF REVIEW

The recent increase in childhood food allergy prevalence strongly suggests that environmental exposures are contributing to food allergy development. This review summarizes current knowledge about the role of the external exposome in food allergy.

RECENT FINDINGS

There is growing evidence that environmental exposure to food antigens in house dust through non-oral routes contributes to food sensitization and allergy. Co-exposure to environmental adjuvants in house dust, such as microbial products and fungal allergens, may also facilitate allergic sensitization. While a high-microbe environment is associated with decreased atopy, studies are mixed on whether endotoxin exposure protects against food sensitization. Several chemicals and air pollutants have been associated with food sensitization, but their role in food allergy remains understudied. Children are exposed to numerous environmental agents that can influence food allergy risk. Further studies are needed to identify the key early-life exposures that promote or inhibit food allergy development.

Possible Role of Environmental Factors in the Development of Food Allergies

The development of food allergies is thought to involve multiple factors, and it is unclear which conveys the most risk regarding this process. Since food allergy is a chronic disease without a cure at this time, understanding its development could provide an avenue for preventive practices and development of a curative treatment. Both historical and current data implicate maternal factors, genetics, and environmental exposures as major risk factors in the development of food allergy. An immature gut of the infant has been hypothesized as a possible route of sensitization. Breastfeeding until at least 6 months of age has been shown to have protective factors for the newborn and may possibly improve gut permeability. Newer studies such as the LEAP and EAT investigations also looked at early exposure and prevention of food allergies; their long-term results are critical in understanding early introduction and tolerance. Cutaneous exposure, oral exposure, and food protein exposure in house dust with their relation to the food allergy course are also a path of interest. Current research has shown sensitization can occur through impaired skin such as those with eczema and a filaggrin mutation. Tropomyosin and alpha-gal also are related to the complicated immunomodulatory factors involved in food allergy and allergic response. Cross-reactivity with plant allergens, sensitization to house dust mite and cockroach, and lone star tick bites can also induce food allergens in children and adults. Together, these factors provide a cohesive beginning to understanding how food allergies can occur and can influence further investigation into prevention, treatment, and eventual cure of food allergies.

Unmet needs of children with peanut allergy: Aligning the risks and the evidence

BACKGROUND

Peanut allergy is a potentially severe and lifelong allergy, with few effective treatments or preventive measures.

OBJECTIVE

To convene an expert panel of allergists, pediatricians, and advocates to discuss and highlight unmet needs in the prevention and management of peanut allergies.

METHODS

Literature searches of PubMed were performed. The panel evaluated published data on the prevention of peanut allergy, treatment of existing peanut allergy, and management of reactions after unintentional peanut exposures.

RESULTS

The following key unmet needs in the prevention and management of peanut allergy were identified: (1) enhancing and optimizing implementation of early peanut introduction as a means of preventing the development of peanut allergy, (2) developing knowledge translation strategies regarding the safety and efficacy data for current and emerging immunotherapies for peanut-allergic children to support their use in clinical practice, and (3) promoting understanding of true exposure risk in allergic individuals and ensuring access to epinephrine for unintentional exposures that provoke severe reactions. Practitioners should help educate caregivers about the actual risks associated with peanut allergy and its prevention and management so that treatment decisions can be evidence based rather than fear based. Support tools are needed to help address caregiver goals, expectations, and psychological barriers, as well as identify facilitators for prevention and treatment strategies.

CONCLUSION

There are significant unmet needs in our understanding of peanut allergy; addressing these needs will help to enhance understanding of how to most effectively prevent and treat peanut allergy, as well as educate the food-allergic and nonallergic community regarding current evidence-based practices.

Food reactions during avoidance: Focus on peanut

OBJECTIVE

Peanut allergy has historically been difficult to manage, with most cases persisting into adulthood. Novel therapies for peanut allergy treatment are on the horizon, yet allergists must maintain a robust understanding of the risks and benefits of the current standard of therapy, avoidance diet.

DATA SOURCES

A comprehensive literature search using PubMed of reviews and clinical articles was performed.

STUDY SELECTIONS

Articles discussing peanut or other food-related allergic reactions, accidental exposures or anaphylaxis pertinent to avoidance diet or comparative to oral immunotherapy trials were selected.

RESULTS

Peanut remains a leading allergen associated with accidental ingestions responsible for food-related reactions, both mild and severe. Fatal reactions, however, are rare and measures such as anaphylaxis plans can significantly decrease the risk of accidental anaphylaxis. Patients may over estimate situations thought to increase risk for reactions to peanut, such as inhalation or contact through skin. In oral immunotherapy trials, the rate of anaphylaxis secondary to treatment was significantly higher than avoidance practices.

CONCLUSION

Clinicians should continue to discuss avoidance as a viable option for long-term peanut allergy management and empower patients to differentiate relevant situations in which accidental reactions might occur.

Epicutaneous sensitization to food allergens in atopic dermatitis: What do we know?

Atopic dermatitis (AD) is a chronic inflammatory skin disease mainly affecting children, which has no definitive curative therapy apart from natural outgrowing. AD is persistent in 30%-40% of children. Epithelial barrier dysfunction in AD is a significant risk factor for the development of epicutaneous food sensitization, food allergy, and other allergic disorders. There is evidence that prophylactic emollient applications from birth may be useful for primary prevention of AD, but biomarkers are needed to guide cost-effective targeted therapy for high-risk individuals. In established early-onset AD, secondary preventive strategies are needed to attenuate progression to other allergic disorders such as food allergy, asthma, and allergic rhinitis (the atopic march). This review aims to describe the mechanisms underpinning the development of epicutaneous sensitization to food allergens and progression to clinical food allergy; summarize current evidence for interventions to halt the progression from AD to food sensitization and clinical food allergy; and highlight unmet needs and directions for future research.

Indoor dust acts as an adjuvant to promote sensitization to peanut through the airway

BACKGROUND

There is growing evidence that environmental peanut exposure through non-oral routes, including the skin and respiratory tract, can result in peanut sensitization. Environmental adjuvants in indoor dust can promote sensitization to inhaled antigens, but whether they contribute to peanut allergy development is unclear.

OBJECTIVE

We investigated whether indoor dust promotes airway sensitization to peanut and peanut allergy development in mice.

METHODS

Female and male C57BL/6J mice were exposed via the airways to peanut, indoor dust extract, or both for 2 weeks. Mice were then challenged with peanut and assessed for anaphylaxis. Peanut-specific immunoglobulins, peanut uptake by lung conventional dendritic cells (cDCs), lung innate cytokines, and T cell differentiation in lung-draining lymph nodes were quantified. Innate cytokine production by primary human bronchial epithelial cells exposed to indoor dust was also determined.

RESULTS

Inhalational exposure to low levels of peanut in combination with indoor dust, but neither alone, resulted in production of peanut-specific IgE and development of anaphylaxis upon peanut challenge. Indoor dust triggered production of innate cytokines in murine lungs and in primary human bronchial epithelial cells. Additionally, inhaled indoor dust stimulated maturation and migration of peanut-laden lung type 1 cDCs to draining lymph nodes. Inhalational exposure to peanut and indoor dust induced peanut-specific T helper 2 cell differentiation and accumulation of T follicular helper cells in draining lymph nodes, which were associated with increased B cell numbers and peanut-specific immunoglobulin production.

CONCLUSIONS & CLINICAL RELEVANCE

Indoor dust promotes airway sensitization to peanut and development of peanut allergy in mice. Our findings suggest that environmental adjuvants in indoor dust may be determinants of peanut allergy development in children.

How to manage food allergy in nursery or school

PURPOSE OF REVIEW

The aim of this review is to describe effective management strategies in nursery or school based upon research findings.

RECENT FINDINGS

The prevalence of food allergy and number of emergency department visits for food-related anaphylaxis are increasing in children and adolescents. As there is currently no cure, the most effective strategy to decrease allergic reactions is food allergen avoidance. However, allergic reactions are inevitable in both food allergic children as well as in first-time reactors. Misconceptions exist on the safety of products with advisory labels and questions remain on whether school-wide bans decrease the risk of allergic reactions in school. Recent legislation has prompted schools to consider requiring unassigned epinephrine autoinjectors to better manage those who have allergic reactions in nursery or school.

SUMMARY

A collective effort is required to keep children with food allergies safe at school. Families, healthcare providers, and school personnel should be informed on food allergen avoidance strategies, symptoms consistent with allergic reactions and anaphylaxis, how to respond to allergic reactions, and the impact the diagnosis of food allergy may have on quality of life for affected children and their families.

Food allergen knowledge, attitude and practices among UK consumers: A structural modelling approach

Food allergies are becoming more prevalent and affect up to 1-2% of adults and 5-8% of children in the UK. This study investigated the food allergen knowledge, attitude towards food allergens and food allergy management practices among food allergic and intolerant consumers and/or their family members and carers. Questionnaires were distributed at three major Free From events in the UK in 2017 and 2018. Structural Equation Modelling (SEM) was used as a confirmatory technique to determine the model's validity. Cereals containing gluten, milk and eggs were the most common triggers reported by the consumers. Other trigger foods such as chocolate, garlic, maize, onions, red and white meat, spices, and fruits such as apples and cherries were also reported. Consumers demonstrated very good understanding on the severity of allergic reactions, prevention method and hidden egg ingredients. Overall, consumers were relatively good in the knowledge section. The participants were motivated in their personal allergen avoidance towards food allergens especially in checking food labels, preference for more free from product choices and handwashing. Consumers did not rely on dietary apps or social media to find out about allergen-free food products. Both knowledge and attitude did not translate into food allergy management practices. Significant correlation between knowledge and attitude was identified suggesting that as knowledge decreases, so will their attitude scores. This study suggests that targeted and systematic food allergy management topics and peer support could be used to improve consumers' knowledge and attitude to positively impact food allergen handling practices.

Environmental Food Exposure: What Is the Risk of Clinical Reactivity From Cross-Contact and What Is the Risk of Sensitization

For food-allergic individuals, the typical exposure to food proteins happens during ingestion; however, individuals may be exposed to foods in other ways. In addition to ingestion reactions, allergic patients may have reactions from cutaneous or mucosal exposures to food proteins, with the classic example being a peanut-allergic child touching a counter with peanut butter and then rubbing their eyes. Similar to hands, saliva can also act as a carrier for food proteins. Finally, there is a wealth of new research regarding the presence of food proteins in the environment, for example, within household floor dust. This review will focus on (1) cross-contact of food proteins and (2) environmental food protein exposures. Cross-contact occurs when one type of food comes into contact with another type of food resulting in the mixture of proteins. For food allergies, cross-contact is important when an allergen is inadvertently transferred to a food/meal that is thought to not contain that specific allergen. We will discuss the current literature regarding the presence of detectable food proteins in different locations, how and if these proteins are transferred or eliminated, and the clinical implications of exposures to food proteins under these different scenarios.

Release of Major Peanut Allergens from Their Matrix under Various pH and Simulated Saliva Conditions-Ara h2 and Ara h6 Are Readily Bio-Accessible

The oral mucosa is the first immune tissue that encounters allergens upon ingestion of food. We hypothesized that the bio-accessibility of allergens at this stage may be a key determinant for sensitization. Light roasted peanut flour was suspended at various pH in buffers mimicking saliva. Protein concentrations and allergens profiles were determined in the supernatants. Peanut protein solubility was poor in the pH range between 3 and 6, while at a low pH (1.5) and at moderately high pHs (>8), it increased. In the pH range of saliva, between 6.5 and 8.5, the allergens Ara h2 and Ara h6 were readily released, whereas Ara h1 and Ara h3 were poorly released. Increasing the pH from 6.5 to 8.5 slightly increased the release of Ara h1 and Ara h3, but the recovery remained low (approximately 20%) compared to that of Ara h2 and Ara h6 (approximately 100% and 65%, respectively). This remarkable difference in the extraction kinetics suggests that Ara h2 and Ara h6 are the first allergens an individual is exposed to upon ingestion of peanut-containing food. We conclude that the peanut allergens Ara h2 and Ara h6 are quickly bio-accessible in the mouth, potentially explaining their extraordinary allergenicity.

A Quantitative Method for Detecting Ara h 2 by Generation and Utilization of Monoclonal Antibodies

Peanut (Arachis hypogaea) is one of the most common food allergens that can induce fatal anaphylaxis, and Ara h 2 is one of the major allergen components involved in peanut allergy. The aim of this study was to develop a quantitative method for detecting peanut allergen using monoclonal antibodies against Ara h 2. The splenocytes of immunized mice were fused with myeloma cells (SP2/0), and stable mAb-producing clones were obtained by limiting dilution. mAbs against Ara h 2 were isolated from mouse ascites, and specificity was confirmed by immunoblotting. Five mAbs with high purity and specific reactivity were obtained, which were referred to as 1-2E10, 2-1D5, 3-1C5, 4-1C2, and 5-1G4, respectively. After screening different mAb combinations for development of a sandwich ELISA, we selected 5-1G4 as the capture antibody and 1-2E10 as the detection antibody for the measurement of Ara h 2 from which an optimal correlation between the Ara h 2 concentration and the OD value was obtained. This sandwich ELISA could specifically detect Ara h 2 in peanut extract at concentrations as low as 5 ng/mL and up to 10 μg/mL. These mAbs can, therefore, serve as quantitative diagnostic reagents for peanut and peanut product risk assessment.

Airborne protein concentration: a key metric for type 1 allergy risk assessment-in home measurement challenges and considerations

Background

Exposure to airborne proteins can be associated with the development of immediate, IgE-mediated respiratory allergies, with genetic, epigenetic and environmental factors also playing a role in determining the likelihood that sensitisation will be induced. The main objective of this study was to determine whether airborne concentrations of selected common aeroallergens could be quantified in the air of homes using easily deployable, commercially available equipment and analytical methods, at low levels relevant to risk assessment of the potential to develop respiratory allergies. Additionally, air and dust sampling were compared and the influence of factors such as different filter types on allergen quantification explored.

Methods

Low volume air sampling pumps and DUSTREAM^® dust samplers were used to sample 20 homes and allergen levels were quantified using a MARIA^® immunoassay.

Results

It proved possible to detect a range of common aeroallergens in the home with sufficient sensitivity to quantify airborne concentrations in ranges relevant to risk assessment (Limits of Detection of 0.005–0.03 ng/m³). The methodology discriminates between homes related to pet ownership and there were clear advantages to sampling air over dust which are described in this paper. Furthermore, in an adsorption–extraction study, PTFE (polytetrafluoroethylene) filters gave higher and more consistent recovery values than glass fibre (grade A) filters for the range of aeroallergens studied.

Conclusions

Very low airborne concentrations of allergenic proteins in home settings can be successfully quantified using commercially available pumps and immunoassays. Considering the greater relevance of air sampling to human exposure of the respiratory tract and its other advantages, wider use of standardised, sensitive techniques to measure low airborne protein concentrations and how they influence development of allergic sensitisation and symptoms could accelerate our understanding of human dose–response relationships and refine our knowledge of thresholds of allergic sensitisation and elicitation via the respiratory tract.

Environmental exposure to peanut and the risk of an allergic reaction

OBJECTIVE

To review the evidence of the risk of environmental exposure to peanut to a peanut allergic individual.

DATA SOURCES AND STUDY SELECTION

A narrative review was performed using a PubMed search of relevant articles involving peanut environmental distribution, environmental peanut abatement, and public policy regarding peanut restriction.

RESULTS

Data from 4 studies have shown that peanut butter vapors and smeared peanut butter on skin do not cause systemic reactions, that peanut can be abated from hands and surfaces using appropriate cleaning agents, and that shelled peanut dust does not become airborne. Studies have recently confirmed dose of 1.5 mg of peanut protein would be generally tolerated by approximately 95% of the peanut-allergic population based on objective symptoms in challenge-based studies, affirming earlier research. Restrictive policies that focus on bans (or restricted presence in certain areas) of peanuts or peanut-containing products in environments such as schools or on commercial aircraft are not backed by evidence that such measures work, which may raise an uncomfortable clash between accommodations that lack any medical evidence of necessity and a desire to provide measures that comfort our patients.

CONCLUSION

There is little risk posed from non-oral exposure to peanut in the environment, from casual contact, proximity, or inhalation. If 5% of the population may tolerate a threshold of approximately 1.5 mg of peanut protein, this may help liberate behavior and situational-decision making regarding the necessity of certain avoidances and restrictions. Continued work is needed to dispel myths about the mechanisms of how peanut may induce an allergic reaction.

Hen's egg allergen in house and bed dust is significantly increased after hen's egg consumption-A pilot study

Environmental exposure to food allergens may be a risk factor for cutaneous sensitization. Previous studies could detect peanut allergen in house dust. In this pilot study, we wanted to investigate whether hen's egg allergen is detectable in house dust collected from different household areas and whether levels are increased after intentional hen's egg consumption. Hen's egg protein levels of dust samples were measured using ELISA. In 8 of 8 households, hen's egg was detectable in dust samples of eating area and bed. Forty-eight hours after intentional hen's egg consumption, hen's egg protein levels were significantly increased in both. Still, further research is necessary to investigate whether hen's egg allergen in house and bed dust plays a role in sensitization via skin.

The Allergist's Role in Anaphylaxis and Food Allergy Management in the School and Childcare Setting

Anaphylaxis and food allergy management in childcare facilities and schools are growing challenges. An increasing number of children experience severe allergic reactions on school grounds as evidenced by reports of epinephrine use. Data also suggest that the prevalence of food allergy may be increasing, with a large percentage of school-aged children at risk for anaphylaxis. Moreover, anaphylaxis may occur for the first time in a previously undiagnosed child at school or childcare setting, suggesting that general preparedness is essential. Management includes strategies for minimizing the risk of reactions and allergen exposures as well as readiness to recognize and treat allergic reactions of any severity. The primary objective of this report is to offer health care providers an overview of relevant evidence, resources, and expert opinion to assist with developing interprofessional collaborative counsel on school food allergy management and anaphylaxis preparedness with families, schools, and childcare settings. We present the current evidence base, suggest resources, and highlight areas of current controversy that warrant further study.

The role of environmental exposure to peanut in the development of clinical allergy to peanut

The prevalence of peanut allergy has increased over the years and still remains one of the most common causes of food-related anaphylaxis. The way in which peanut sensitization occurs has been explored, such as via maternal consumption in pregnancy, via breastmilk and through a disrupted skin barrier. It has previously been shown that environmental exposure to aeroallergens in household dust can be a risk factor for the development of allergic asthma. There is an increasing body of evidence that the combination of cutaneous sensitization via a disrupted skin barrier (ie children with eczema or with filaggrin mutations) and environmental peanut exposure influences the development of peanut allergy. This review aims to explore routes of peanut sensitization and the current evidence on how environmental exposure to peanut affects the development of peanut allergy.

Pros and Cons of Clinical Basophil Testing (BAT)

PURPOSE OF REVIEW

We review basophil testing by flow cytometry with an emphasis on advantages and disadvantages.

RECENT FINDINGS

There are many tools available to assess the presence and severity of allergic diseases in patients. For 50 years, peripheral blood basophils have been used as tools to study these diseases. It is a very accessible cell that binds IgE antibody and secretes the classical mediators responsible for the symptoms of allergic reactions. In the last decade, an even more accessible methodology, using flow cytometry, has been developed to enhance the ability to use basophils for both mechanistic and clinical diagnostics. Basophil testing has been included in diagnostics for different forms of allergies as well as to monitor disease status. A variety of studies have begun to establish both precise methods and their clinical relevance for disease diagnosis, but there remain some important questions on how to take optimal advantage of the behaviours of basophils.

Ara h2 levels in dust from homes of individuals with peanut allergy and individuals with peanut tolerance

BACKGROUND

Approximately 1% of the U.S. population has a peanut allergy. Previous studies that measured peanut protein in house dust support the hypothesis that household peanut consumption may lead to clinical sensitization through transdermal exposure.

OBJECTIVE

The aim of this pilot study was to characterize Ara h2 levels in house dust from homes with and without individuals with peanut allergy.

METHODS

Household dust was obtained from homes with an individual with peanut allergy and from homes with no individual with peanut allergy. Ara h2 levels were determined by using a monoclonal antibody-based immunoassay with a level of determination of 150 ng per gram of dust. Peanut consumption information was obtained by questionnaire.

RESULTS

A total of 85 dust samples were collected: 38 from homes with a individual with peanut allergy and 47 from control homes. The median Ara h2 level in homes with an individual with peanut allergy was 1236 ng/g (interquartile range [IQR], 256-1342 ng/g), whereas the median Ara h2 level in homes without an individual with peanut allergy was 650 ng/g (IQR, 163-2201 ng/g). Ara h2 levels in dust from homes of individuals with peanut allergy were not significantly lower than in dust from control homes. Of the homes with an individual with peanut allergy, 15 reported complete avoidance of peanut in the home (39%). Ara h2 levels in homes that completely avoided peanuts were not significantly lower than Ara h2 levels in homes that did not restrict peanuts (p = 0.531).

CONCLUSION

Although families may restrict peanuts and peanut products in the home, there was still detectable Ara h2 levels found in homes. Each subject's definition of restriction may vary, there seemed to be peanut protein entering the home, although the protein origin is not known. Possibilities include cross-reactivity with another antigen or transport into the home on some vector. Further investigation of hypotheses regarding cross-reactivity and environmental exposure to Ara h2 is necessary.