The global burden of illness of peanut allergy: A comprehensive literature review

Two-year post-treatment outcomes following peanut oral immunotherapy in the Probiotic and Peanut Oral Immunotherapy-003 Long-Term (PPOIT-003LT) study

BACKGROUND

Few studies have examined long-term outcomes following oral immunotherapy (OIT); none have examined long-term risks and benefits associated with distinct clinical outcomes (desensitization, remission).

METHODS

Participants completing the probiotic and peanut oral immunotherapy (PPOIT) -003 randomized trial were enrolled in a follow-on study, PPOIT-003LT. Peanut ingestion, reactions, and health-related quality of life (HRQOL) were monitored prospectively. Outcomes at 1-year and 2-years post-treatment were examined by treatment group and by post-OIT clinical outcome (remission, desensitization without remission [DWR], allergic).

RESULTS

86% (151/176) of eligible children enrolled. Post-treatment peanut ingestion at 2-years post-treatment were similar for PPOIT (86.7%) and OIT (78.7%) groups, both higher than placebo (10.3%). Reactions reduced over time for all treatment and clinical outcome groups (PPOIT 31.7% to 23.3%, OIT 37.7% to 19.7%, placebo 13.8% to 6.9%; remission 27.5% to 15.9%; DWR 57.9% to 36.8%; allergic 11.6% to 7%). At 2-years post-treatment, similar proportions of remission and allergic participants reported reactions (RD 0.09 (95%CI -0.03, 0.20), p = .127), whereas more DWR participants reported reactions than remission (remission vs DWR: RD -0.21 (95%CI -0.39; -0.03), p = .02) and allergic (DWR vs allergic: RD 0.30 (95%CI 0.13, 0.47), p = .001) participants. At 2-years post-treatment, 0% remission versus 5.3% DWR versus 2.3% allergic participants reported adrenaline injector usage. Remission participants had significantly greater HRQOL improvement (adjusted for baseline) compared with both DWR (MD -0.54 (95%CI -0.99, -0.10), p = .017) and allergic (MD -0.82 (95%CI -1.25, -0.38), p < .001).

CONCLUSION

By 2-years post-treatment, remission participants reported fewer reactions, less severe reactions and greater HRQOL improvement compared with DWR and allergic participants, indicating that remission is the patient-preferred treatment outcome over desensitization or remaining allergic.

Clinical utility analysis of the Hoxb8 mast cell activation test for the diagnosis of peanut allergy

BACKGROUND

Peanut allergy is among the most severe and common food allergies. The diagnosis has a significant impact on the quality of life for patients and their families. An effective management approach depends on accurate, safe, and easily implementable diagnostic methods. We previously developed a cell-based assay using Hoxb8 mast cells (Hoxb8 MCs) aimed at improving clinical allergy diagnosis. In this study, we assessed its diagnostic performance by measuring blinded sera from a prospectively enrolled and pre-validated peanut allergy cohort.

METHODS

Hoxb8 MCs were passively sensitized with sera from peanut-allergic and peanut tolerant children and adolescents (n = 112). Degranulation of Hoxb8 MCs was quantified upon stimulation with dose-titrated peanut extract by means of flow cytometry, using CD107a as activation marker. The results from the Hoxb8 mast cell activation test (Hoxb8 MAT) were compared to established diagnostic assays such as the skin prick test (SPT), specific IgE (sIgE) levels, and the basophil activation test (BAT). Additionally, serum samples from BAT nonresponders were assessed with the Hoxb8 MAT.

RESULTS

Hoxb8 MAT displayed a robust dose-dependent activation to peanut extract, with a cutoff value of ≤5.2% CD107a positive cells. The diagnostic accuracy was highest at allergen concentrations ≥100 ng/mL, with an area under the receiver operating characteristic curve (AUROC) of 0.97, 93% sensitivity, and 96% specificity, outperforming traditional SPT and sIgE tests. When compared to BAT, Hoxb8 MAT exhibited comparable diagnostic efficacy. Moreover, sera from BAT nonresponders were accurately classified into allergics and nonallergics by the Hoxb8 MAT.

CONCLUSIONS

The Hoxb8 MAT demonstrated a very good diagnostic precision in patients prospectively assessed for peanut allergy comparable to the fresh whole blood-based BAT. Additionally, it demonstrated its value for accurate classification of BAT nonresponders into allergic and nonallergic individuals. Further investigations into its utility in the routine clinical setting are warranted.

Legume Allergens Pea, Chickpea, Lentil, Lupine and Beyond

PURPOSE OF THE REVIEW

In the last decade, an increasing trend towards a supposedly healthier vegan diet could be observed. However, recently, more cases of allergic reactions to plants and plant-based products such as meat-substitution products, which are often prepared with legumes, were reported. Here, we provide the current knowledge on legume allergen sources and the respective single allergens. We answer the question of which legumes beside the well-known food allergen sources peanut and soybean should be considered for diagnostic and therapeutic measures.

RECENT FINDINGS

These "non-priority" legumes, including beans, pea, lentils, chickpea, lupine, cowpea, pigeon pea, and fenugreek, are potentially new important allergen sources, causing mild-to-severe allergic reactions. Severe reactions have been described particularly for peas and lupine. An interesting aspect is the connection between anaphylactic reactions and exercise (food-dependent exercise-induced anaphylaxis), which has only recently been highlighted for legumes such as soybean, lentils and chickpea. Most allergic reactions derive from IgE cross-reactions to homologous proteins, for example between peanut and lupine, which is of particular importance for peanut-allergic individuals ignorant to these cross-reactions. From our findings we conclude that there is a need for large-scale studies that are geographically distinctive because most studies are case reports, and geographic differences of allergic diseases towards these legumes have already been discovered for well-known "Big 9" allergen sources such as peanut and soybean. Furthermore, the review illustrates the need for a better molecular diagnostic for these emerging non-priority allergen sources to evaluate IgE cross-reactivities to known allergens and identify true allergic reactions.

IgE-Mediated Legume Allergy: A Pediatric Perspective

Legumes are an inexpensive and essential protein source worldwide. The most consumed legumes include peanuts, soybeans, lentils, lupines, peas, common bean and chickpeas. In addition, the food industry is growing interested in expanding the use of legumes to partially replace or substitute cereals. Legumes were described to cause IgE-mediated allergies, and their growing use may also increase the incidence of allergy. The epidemiology of legume allergy varies by region; peanuts and soybeans are the legumes most involved in food allergies in Western countries, whereas lentils, peas, and chickpeas are reported as culprit allergens mainly in the Mediterranean area and India. This review, edited by the Italian Society of Pediatric Allergology and Immunology, summarizes the scientific literature on legume allergy in children and proposes a diagnostic workup and therapeutic approach.

Peanut hulls, an underutilized nutritious culinary ingredient: valorizing food waste for global food, health, and farm economies-a narrative review

Peanut hulls (PHs) are an edible food waste that is an underutilized food source for human consumption. While edible and palatable, currently they are mainly diverted to livestock feed or building materials. Here, we describe existing literature supporting human food valorization of PHs, and propose methods to optimize recapturing nutrients (protein, fiber, phenols and other phytonutrients) lost by treating PHs as waste. Incorporated into common foods, PHs could be processed into functional ingredients to improve nutrient-density with anticipated corresponding positive health outcomes associated with increases in plant foods. Valorization of PHs addresses multiple priorities of the UN Sustainable Development Goals using a Food Systems Approach (FSA) including reducing food waste, increasing economic opportunities for farmers, and increasing the availability of healthy shelf-stable foodstuffs to address food security. Recent advances in sustainable food processing technologies can be utilized to safely incorporate PHs into human food streams. We propose future applications that could make meaningful impacts for food availability and the nutritional composition of common foods like bread and plant-based meat alternatives. While the limited literature on this topic spans several decades, no commercial operations currently exist to process PHs for human consumption, and most literature on the topic precedes the technological "green revolution." The approaches outlined in this review may help bolster commercialization of this underutilized and nutritious food potentially improving opportunities for multiple global stakeholders.

Food allergy in a changing dietary landscape: A focus on the Asia Pacific region

Recent studies have provided compelling evidence to suggest that various environmental factors play a significant role in the development of food allergies. As our society experiences rapid economic growth, increased urbanization, and a shift towards a more Westernized diet, the incidence of food allergies is also on the rise and the pattern is gradually evolving. This review will delve into the changes in the epidemiology of food allergies within the Asia-Pacific region and the various dietary practices and factors that are postulated to play a role in the rise in food allergies over the years. Although there have been important advancements in the field of food allergies, there are still numerous uncertainties regarding the intricate relationship between diet and food allergies. Specifically, the role of epigenetic factors in influencing the susceptibility to food allergies, as evidenced by studies that assessed the impact of migration and rural-urban dynamics, is not fully understood. Addressing this knowledge gap presents an opportunity to develop more effective prevention and treatment strategies that could greatly benefit individuals living with food allergies.

Racial and Socioeconomic Disparities Exist in Patients Pursuing Peanut Oral Immunotherapy

BACKGROUND

Oral immunotherapy (OIT) is a promising treatment for food allergy. Prior studies demonstrate significant differences among food-allergic individuals across race, ethnicity, and socioeconomic groups. Disparities in OIT have not been evaluated.

OBJECTIVE

We assessed disparities in the use of OIT in patients with peanut allergy based on race, ethnicity, and socioeconomic status at a single academic medical center.

METHODS

We identified 1028 peanut-allergic patients younger than 18 years receiving care in the University of Michigan food allergy clinics. Of these, 148 patients who underwent peanut OIT (treatment group) were compared with the 880 patients who avoided peanut (control group). Pertinent demographic and socioeconomic characteristics were compared.

RESULTS

There were no differences in gender or ethnicity between the OIT and control groups. However, Black patients comprised 18% of the control group but only 4.1% of the OIT treatment group (P < .0001). The proportion of patients with private insurance was significantly higher in the treatment group compared with the control group (93.2% vs 82.2%, P = .0004). Finally, the neighborhood affluence index, a census-based measure of the relative socioeconomic prosperity of a neighborhood, was significantly higher in the OIT group than the control group (0.51 ± 0.18 vs 0.47 ± 0.19, P = .015), whereas the neighborhood disadvantage index, a census-based measure of the relative socioeconomic disadvantage of a neighborhood, was significantly lower (0.082 ± 0.062 vs 0.10 ± 0.093, P = .020).

CONCLUSIONS

Significant racial and economic disparities exist at our institution between peanut-allergic individuals who receive OIT and those who do not. Efforts to understand the basis for these disparities are important to ensure that patients have equitable access to OIT.

Preclinical efficacy of peanut-specific IgG4 antibody therapeutic IGNX001

BACKGROUND

Existing therapeutic strategies are challenged by long times to achieve effect and often require frequent administration. Peanut-allergic individuals would benefit from a therapeutic that provides rapid protection against accidental exposure within days of administration while carrying little risk of adverse reactions.

OBJECTIVE

Guided by the repertoire of human IgE mAbs from allergic individuals, we sought to develop a treatment approach leveraging the known protective effects of allergen-specific IgG4 antibodies.

METHODS

We applied our single-cell RNA-sequencing SEQ SIFTER platform (IgGenix, Inc, South San Francisco, Calif) to whole blood samples from peanut-allergic individuals to discover IgE mAbs. These were then class-switched by replacing the IgE constant region with IgG4 while retaining the allergen-specific variable regions. In vitro mast cell activation tests, basophil activation tests, ELISAs, and an in vivo peanut allergy mouse model were used to evaluate the specificity, affinity, and activity of these recombinant IgG4 mAbs.

RESULTS

We determined that human peanut-specific IgE mAbs predominantly target immunodominant epitopes on Ara h 2 and Ara h 6 and that recombinant IgG4 mAbs effectively block these epitopes. IGNX001, a mixture of 2 such high-affinity IgG4 mAbs, provided robust protection against peanut-mediated mast cell activation in vitro as well as against anaphylaxis upon intragastric peanut challenge in a peanut allergy mouse model.

CONCLUSIONS

We developed a peanut-specific IgG4 antibody therapeutic with convincing preclinical efficacy starting from a large repertoire of human IgE mAbs from demographically and geographically diverse individuals. These results warrant further clinical investigation of IGNX001 and underscore the opportunity for the application of this therapeutic development strategy in other food and environmental allergies.

Enhanced Gut Microbiome Capacity for Amino Acid Metabolism is associated with Peanut Oral Immunotherapy Failure

Peanut Oral Immunotherapy (POIT) holds promise for remission of peanut allergy, though treatment is protracted and successful in only a subset of patients. Because the gut microbiome is linked to food allergy, we sought to identify fecal microbial predictors of POIT efficacy and to develop mechanistic insights into treatment response. Longitudinal functional analysis of the fecal microbiome of children (n=79) undergoing POIT in a first double-blind, placebo-controlled clinical trial, identified five microbial-derived bile acids enriched in fecal samples prior to POIT initiation that predicted treatment efficacy (AUC 0.71). Failure to induce disease remission was associated with a distinct fecal microbiome with enhanced capacity for bile acid deconjugation, amino acid metabolism, and increased peanut peptide degradation in vitro . Thus, microbiome mechanisms of POIT failure appear to include depletion of immunomodulatory secondary bile and amino acids and the antigenic peanut peptides necessary to promote peanut allergy desensitization and remission.

Angiotensin-Converting Enzyme and Renin-Inhibitory Activities of Protein Hydrolysates Produced by Alcalase Hydrolysis of Peanut Protein

Hypertension is a major controllable risk factor associated with cardiovascular disease (CVD) and overall mortality worldwide. Most people with hypertension must take medications that are effective in blood pressure management but cause many side effects. Thus, it is important to explore safer antihypertensive alternatives to regulate blood pressure. In this study, peanut protein concentrate (PPC) was hydrolyzed with 3-5% Alcalase for 3-10 h. The in vitro angiotensin-converting enzyme (ACE) and renin-inhibitory activities of the resulting peanut protein hydrolysate (PPH) samples and their fractions of different molecular weight ranges were determined as two measures of their antihypertensive potentials. The results show that the crude PPH produced at 4% Alcalase for 6 h of hydrolysis had the highest ACE-inhibitory activity with IC50 being 5.45 mg/mL. The PPH samples produced with 3-5% Alcalase hydrolysis for 6-8 h also displayed substantial renin-inhibitory activities, which is a great advantage over the animal protein-derived bioactive peptides or hydrolysate. Remarkably higher ACE- and renin-inhibitory activities were observed in fractions smaller than 5 kDa with IC50 being 0.85 and 1.78 mg/mL. Hence, the PPH and its small molecular fraction produced under proper Alcalase hydrolysis conditions have great potential to serve as a cost-effective anti-hypertensive ingredient for blood pressure management.

Age-Related Food Aversion and Anxiety Represent Primary Patient Barriers to Food Oral Immunotherapy

BACKGROUND

Although oral immunotherapy (OIT) for food allergy is a reasonable treatment option, barriers to this procedure's implementation have not been extensively evaluated from a patient perspective.

OBJECTIVE

We evaluated the barriers patients face during OIT administration, including anxiety and taste aversion, and the role of health care professionals, especially dietitians.

METHODS

A survey in Canada and the United States involved families currently enrolled in food OIT programs.

RESULTS

Of responses from 379 participants, fear of reaction was the most common barrier to OIT initiation, with 45.6% reporting it being a "very significant" barrier with other fears reported. However, taste aversion represented the prominent obstacle to continuation. Taste aversion was associated with a slower buildup (P = .02) and a reduction in dose (P = .002). Taste aversion was a strongly age-dependent barrier for initiation (P < .001) and continuation (P < .002), with older children over 6 years of age reporting it as a very significant barrier (P < .001). Boredom was reported as a concern for specific allergens such as peanut, egg, sesame, and hazelnuts (P < .05), emphasizing the need for diverse food options. Notably, 59.9% of respondents mixed OIT foods with sweet items. Despite these dietary concerns, dietitians were underutilized, with only 9.5% of respondents having seen a dietitian and the majority finding dietitian support helpful with greater certainty about the exact dose (P < .001).

CONCLUSIONS

Taste aversion and anxiety represent primary patient-related barriers to OIT. Taste aversion was highly age dependent, with older patients being more affected. Dietitians and psychology support were underutilized, representing a critical target to improve adherence and OIT success.

Identifying thresholds of reaction for different foods

Current food allergy management universally treats all patients with food allergy as being at risk for anaphylaxis (with the exception perhaps of pollen food allergy syndrome). Thus, patients are told to avoid the allergenic food in all potentially allergic forms and amounts. However, research over the past 2 decades has shown that many patients will tolerate small amounts of the allergen without any allergic reaction. Thus, if one were able to identify the threshold of reactivity, this could change management. At the population level, establishing levels at which the vast majority of patients (e.g., 95%) do not react could have public health ramifications, such as altering labeling laws. At the individual patient level, personal threshold levels could determine avoidance strategies, affect quality of life, and alter treatment decisions, e.g., oral immunotherapy starting doses. In this review, threshold data for various allergens and their potential effect on the management of the patient with food allergy are examined.

Groundnut and tree nuts: a comprehensive review on their lipid components, phytochemicals, and nutraceutical properties

The health benefits of nut consumption have been extensively demonstrated in observational studies and intervention trials. Besides the high nutritional value, countless evidences show that incorporating nuts into the diet may contribute to health promotion and prevention of certain diseases. Such benefits have been mostly and certainly attributed not only to their richness in healthy lipids (plentiful in unsaturated fatty acids), but also to the presence of a vast array of phytochemicals, such as polar lipids, squalene, phytosterols, tocochromanols, and polyphenolic compounds. Thus, many nut chemical compounds apply well to the designation "nutraceuticals," a broad umbrella term used to describe any food component that, in addition to the basic nutritional value, can contribute extra health benefits. This contribution analyses the general chemical profile of groundnut and common tree nuts (almond, walnut, cashew, hazelnut, pistachio, macadamia, pecan), focusing on lipid components and phytochemicals, with a view on their bioactive properties. Relevant scientific literature linking consumption of nuts, and/or some of their components, with ameliorative and/or preventive effects on selected diseases - such as cancer, cardiovascular, metabolic, and neurodegenerative pathologies - was also reviewed. In addition, the bioactive properties were analyzed in the light of known mechanistic frameworks.

Evaluation and Modification of a Shared Decision-Making Tool for Peanut Allergy Management

PURPOSE OF REVIEW

Based on shared decision-making (SDM) principles, a decision aid was previously developed to help patients, their caregivers, and physicians decide which peanut allergy management approach best suits them. This study refined the decision aid's content to better reflect patients' and caregivers' lived experience.

RECENT FINDINGS

Current standard of care for peanut allergy is avoidance, although peanut oral immunotherapy has been approved by the Food and Drug Administration for use in patients 4-17 years old. An advisory board of allergy therapy experts (n = 3) and patient advocates (n = 3) informed modifications to the decision aid. The revised tool underwent cognitive debriefing interviews (CDIs) among adolescents (12-17 years old) with peanut allergy and caregivers of patients 4-17 years old with peanut allergy to evaluate its relevance, understandability, and usefulness. The 20 CDI participants understood the information presented in the SDM tool and reported it was important and relevant. Some revisions were made based on participant feedback. Results support content validity of the Peanut Allergy Treatment SDM Tool.

Joint transcriptomic and cytometric study of children with peanut allergy reveals molecular and cellular cross talk in reaction thresholds

BACKGROUND

Reaction thresholds in peanut allergy are highly variable. Elucidating causal relationships between molecular and cellular processes associated with variable thresholds could point to therapeutic pathways for raising thresholds.

OBJECTIVE

The aim of this study was to characterize molecular and cellular systemic processes associated with reaction threshold in peanut allergy and causal relationships between them.

METHODS

A total of 105 children aged 4 to 14 years with suspected peanut allergy underwent double-blind, placebo-controlled food challenge to peanut. The cumulative peanut protein quantity eliciting allergic symptoms was considered the reaction threshold for each child. Peripheral blood samples collected at 0, 2, and 4 hours after challenge start were used for RNA sequencing, whole blood staining, and cytometry. Statistical and network analyses were performed to identify associations and causal mediation between the molecular and cellular profiles and peanut reaction threshold.

RESULTS

Within the cohort (N = 105), 81 children (77%) experienced allergic reactions after ingesting varying quantities of peanut, ranging from 43 to 9043 mg of cumulative peanut protein. Peripheral blood expression of transcripts (eg, IGF1R [false discovery rate (FDR) = 5.4e-5] and PADI4 [FDR = 5.4e-5]) and neutrophil abundance (FDR = 9.5e-4) were associated with peanut threshold. Coexpression network analyses revealed that the threshold-associated transcripts were enriched in modules for FcγR-mediated phagocytosis (FDR = 3.2e-3) and Toll-like receptor (FDR = 1.4e-3) signaling. Bayesian network, key driver, and causal mediation analyses identified key drivers (AP5B1, KLHL21, VASP, TPD52L2, and IGF2R) within these modules that are involved in bidirectional causal mediation relationships with neutrophil abundance.

CONCLUSION

Key driver transcripts in FcγR-mediated phagocytosis and Toll-like receptor signaling interact bidirectionally with neutrophils in peripheral blood and are associated with reaction threshold in peanut allergy.

Preparing Patients for Oral Immunotherapy (PPOINT): International Delphi consensus for procedural preparation and consent

BACKGROUND

Despite the promise of oral immunotherapy (OIT) to treat food allergies, this procedure is associated with potential risk. There is no current agreement about what elements should be included in the preparatory or consent process.

OBJECTIVE

We developed consensus recommendations about the OIT process considerations and patient-specific factors that should be addressed before initiating OIT and developed a consensus OIT consent process and information form.

METHODS

We convened a 36-member Preparing Patients for Oral Immunotherapy (PPOINT) panel of allergy experts to develop a consensus OIT patient preparation, informed consent process, and framework form. Consensus for themes and statements was reached using Delphi methodology, and the consent information form was developed.

RESULTS

The expert panel reached consensus for 4 themes and 103 statements specific to OIT preparatory procedures, of which 76 statements reached consensus for inclusion specific to the following themes: general considerations for counseling patients about OIT; patient- and family-specific factors that should be addressed before initiating OIT and during OIT; indications for initiating OIT; and potential contraindications and precautions for OIT. The panel reached consensus on 9 OIT consent form themes: benefits, risks, outcomes, alternatives, risk mitigation, difficulties/challenges, discontinuation, office policies, and long-term management. From these themes, 219 statements were proposed, of which 189 reached consensus, and 71 were included on the consent information form.

CONCLUSION

We developed consensus recommendations to prepare and counsel patients for safe and effective OIT in clinical practice with evidence-based risk mitigation. Adoption of these recommendations may help standardize clinical care and improve patient outcomes and quality of life.

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.).

Peanut oral immunotherapy using an extensively heated and baked novel composition of peanuts

BACKGROUND

Oral immunotherapy (OIT) is an increasingly acceptable therapeutic option for peanut-allergic (PA) children, despite significant side effects. Major peanut allergenic proteins are heat-resistant and are not rendered hypoallergenic after baking or cooking. Lyophilized peanut protein-MH (LPP-MH) is a novel composition from developing peanuts, enabling cooking-induced reduction in allergenicity. We aimed to explore the safety and efficacy of OIT, with extensively heated and baked (EHEB) LPP-MH in PA children.

METHODS

In a single-arm, single-center, pilot study, PA children with a single highest tolerated dose of <100 mg peanut protein were placed on a 40-week OIT protocol with 300 mg daily of heat-treated LPP-MH. A repeat open peanut food challenge was performed after 40 weeks of treatment and at a 6-12 months of follow-up visit.

RESULTS

Thirty-three children with PA were enrolled, with a mean cumulative tolerated dose (MCTD) of 71.2 mg PP (95% CI 45-100 mg). After 40 weeks, 32/33 patients were able to consume more than 300 mg of natural PP, with MCTD of 1709 mg (CI 365-3675 mg). There were no severe allergic reactions requiring epinephrine, during any of the observed LPP-MH challenges or any treatment related doses at home. After 6-12 months on daily maintenance, the MCTD was 8821 mg (95% CI 1930-13,500 mg). This enabled most children age-appropriate dietary inclusion of peanuts.

CONCLUSION

An OIT protocol with heat-treated LPP-MH, a novel composition from developing peanuts, seems a potentially safe and efficacious OIT modality for PA children, enabling the introduction of dietary levels of peanut proteins in highly allergic PA children. Validation in randomized controlled studies is mandated.

How accurate is the human olfactory system in detecting peanuts?

KEY POINTS

This is the first study to quantify the accuracy, sensitivity, and specificity of the human olfactory system in detecting peanuts in common food items. With more competing sensory input, the human olfactory sensitivity to peanuts decreases; this is especially evident when peanuts are mixed in sauces. Metrics established in this study can be used to develop standards for determining the clinical utility of allergen detecting devices that are currently under development.

Novel post-translationally cleaved Ara h 2 proteoforms: Purification, characterization and IgE-binding properties

The 2S albumins Ara h 2 and Ara h 6 have been shown to be the most important source of allergenicity in peanut. Several isoforms of these allergens have been described. Using extraction and liquid chromatography we isolated proteins with homology to Ara h 2 and characterized hitherto unknown Ara h 2 proteoforms with additional post-translational cleavage. High-resolution mass spectrometry located the cleavage site on the non-structured loop of Ara h 2 while far UV CD spectroscopy showed a comparable structure to Ara h 2. The cleaved forms of Ara h 2 were present in genotypes of peanut commonly consumed. Importantly, we revealed that newly identified Ara h 2 cleaved proteoforms showed comparable IgE-binding using sera from 28 peanut-sensitized individuals, possessed almost the same IgE binding potency and are likely similarly allergenic as intact Ara h 2. This makes these newly identified forms relevant proteoforms of peanut allergen Ara h 2.

Major peanut allergens are quickly released from peanuts when seeds are hydrated under specific conditions

Allergens release from their biological source is a critical step in allergic sensitization. We sought to investigate in vitro the role of hydration at 1:10 w/v without stirring and 1:5 w/v with and without stirring on the release of major and minor allergens from peanut kernels. We hypothesized that hydration plays a pivotal role in peanut allergens release, affecting major allergens predominantly, and that peanut-water ratio and stirring influence allergen diffusion. We found that major peanut allergen Ara h 1 was quickly released during hydration leading to a decrease in its content in the seed particularly at hydration performed at 1:5 w/v with stirring. Ara h 2 remained more preserved in the hydrated seed, while Ara h 3 showed no content decrease despite its important release into the hydration water. Minor allergens Ara h 8 and Ara h 9 have lower abundance in peanut leading to a reduction of their content in the seed after their diffusion into the water during hydration. The results also demonstrated that a higher seed-to-water ratio (1:5 w/v) and stirring had a more pronounced impact on allergen release.

The Magnitude and Impact of Food Allergens and the Potential of AI-Based Non-Destructive Testing Methods in Their Detection and Quantification

Reaction to food allergens is on the increase and so is the attending cost on consumers, the food industry, and society at large. According to FDA, the "big-eight" allergens found in foods include wheat (gluten), peanuts, egg, shellfish, milk, tree nuts, fish, and soybeans. Sesame was added to the list in 2023, making the target allergen list nine instead of eight. These allergenic foods are major ingredients in many food products that can cause severe reactions in those allergic to them if found at a dose that can elicit a reaction. Defining the level of contamination that can elicit sensitivity is a work in progress. The first step in preventing an allergic reaction is reliable detection, then an effective quantification method. These are critical steps in keeping contaminated foods out of the supply chain of foods with allergen-free labels. The conventional methods of chemical assay, DNA-PCR, and enzyme protocols like enzyme-linked immunosorbent assay are effective in allergen detection but slow in providing a response. Most of these methods are incapable of quantifying the level of allergen contamination. There are emerging non-destructive methods that combine the power of sensors and machine learning to provide reliable detection and quantification. This review paper highlights some of the critical information on the types of prevalent food allergens, the mechanism of an allergic reaction in humans, the measure of allergenic sensitivity and eliciting doses, and the conventional and emerging AI-based methods of detection and quantification-the merits and downsides of each type.

The clinical burden of food allergies: Insights from the Food Allergy Research & Education (FARE) Patient Registry

Background

Food allergies are serious and potentially life-threatening, and often place a large burden on patients and their caregivers, including impacts on quality of life.

Objective

To assess the real-world patient burden of food allergies, using self-reported data available from the Food Allergy Research & Education (FARE) Patient Registry (NCT04653324).

Methods

The FARE Patient Registry is voluntary and captures real-world experiences of adults and pediatric patients in the United States, and their caregivers, through a series of surveys assessing patient health and experiences with food allergies. Self-reported data were descriptively analyzed.

Results

The FARE study cohort included 5587 patients with food allergies; 82% had multiple food allergies and 62% were aged <18 years. About half of the patients were first diagnosed by an allergist/immunologist (53%), most commonly with a skin prick test (71%) or a serum immunoglobulin E test (62%). This analysis found that food allergies (most commonly peanut [66%], tree nuts [61%], egg [43%], and milk [37%]) impart a large clinical burden on patients, many of whom experience food-related allergic reactions and comorbidities. Many patients experienced >1 food-related allergic reaction per year (42%), with 46% experiencing food-induced anaphylaxis. Half of all food-related allergic reactions occurred at home. Accidental exposures to food allergens were experienced by 77% of patients. The most common allergic comorbidities reported by patients with food allergies were atopic dermatitis (48%), asthma (46%), and allergic rhinitis (39%). The clinical burden of food allergies were found to be greater in patients with multiple food allergies, and different for adults versus pediatric patients.

Conclusion

This is the first study to assess patient experience and disease burden information from patients contributing to the FARE Patient Registry, thus providing a unique insight into the lives of patients in the United States with food allergies. These insights may assist clinicians and other public health stakeholders in the management of patients with food allergies.

Phase 1 trial supports safety and mechanism of action of peptide immunotherapy for peanut allergy

BACKGROUND

Food allergy is a leading cause of anaphylaxis worldwide. Allergen-specific immunotherapy is the only treatment shown to modify the natural history of allergic disease, but application to food allergy has been hindered by risk of severe allergic reactions and short-lived efficacy. Allergen-derived peptides could provide a solution. PVX108 comprises seven short peptides representing immunodominant T-cell epitopes of major peanut allergens for treatment of peanut allergy.

METHODS

Pre-clinical safety of PVX108 was assessed using ex vivo basophil activation tests (n = 185). Clinical safety and tolerability of single and repeat PVX108 doses were evaluated in a first-in-human, randomized, double-blind, placebo-controlled trial in peanut-allergic adults (46 active, 21 placebo). The repeat-dose cohort received six doses over 16 weeks with safety monitored to 21 weeks. Exploratory immunological analyses were performed at pre-dose, Week 21 and Month 18 after treatment.

RESULTS

PVX108 induced negligible activation of peanut-sensitised basophils. PVX108 was safe and well tolerated in peanut-allergic adults. There were no treatment-related hypersensitivity events or AEs of clinical concern. The only events occurring more frequently in active than placebo were mild injection site reactions. Exploratory immunological analyses revealed a decrease in the ratio of ST2+ Th2A:CCR6+ Th17-like cells within the peanut-reactive Th pool which strengthened following treatment.

CONCLUSION

This study supports the concept that PVX108 could provide a safe alternative to whole peanut immunotherapies and provides evidence of durable peanut-specific T-cell modulation. Translation of these findings to clinical efficacy in ongoing Phase 2 trials would provide important proof-of-concept for using peptides to treat food allergy.

Different airborne particulates trigger distinct immune pathways leading to peanut allergy in a mouse model

BACKGROUND

Environmental exposure to peanut through non-oral routes is a risk factor for peanut allergy. Early-life exposure to air pollutants, including particulate matter (PM), is associated with sensitization to foods through unknown mechanisms. We investigated whether PM promotes sensitization to environmental peanut and the development of peanut allergy in a mouse model.

METHODS

C57BL/6J mice were co-exposed to peanut and either urban particulate matter (UPM) or diesel exhaust particles (DEP) via the airways and assessed for peanut sensitization and development of anaphylaxis following peanut challenge. Peanut-specific CD4+ T helper (Th) cell responses were characterized by flow cytometry and Th cytokine production. Mice lacking select innate immune signaling genes were used to study mechanisms of PM-induced peanut allergy.

RESULTS

Airway co-exposure to peanut and either UPM- or DEP-induced systemic sensitization to peanut and anaphylaxis following peanut challenge. Exposure to UPM or DEP triggered activation and migration of lung dendritic cells to draining lymph nodes and induction of peanut-specific CD4+ Th cells. UPM- and DEP-induced distinct Th responses, but both stimulated expansion of T follicular helper (Tfh) cells essential for peanut allergy development. MyD88 signaling was critical for UPM- and DEP-induced peanut allergy, whereas TLR4 signaling was dispensable. DEP-induced peanut allergy and Tfh-cell differentiation depended on IL-1 but not IL-33 signaling, whereas neither cytokine alone was necessary for UPM-mediated sensitization.

CONCLUSION

Environmental co-exposure to peanut and PM induces peanut-specific Tfh cells and peanut allergy in mice.

Investigation of peanut allergen-procyanidin non-covalent interactions: Impact on protein structure and in vitro allergenicity

Interactions between plant polyphenols and food allergens may be a new way to alleviate food allergies. The non-covalent interactions between the major allergen from peanut (Ara h 2) with procyanidin dimer (PA2) were therefore characterized using spectroscopic, thermodynamic, and molecular simulation analyses. The main interaction between the Ara h 2 and PA2 was hydrogen bonding. PA2 statically quenched the intrinsic fluorescence intensity and altered the conformation of the Ara h 2, leading to a more disordered polypeptide structure with a lower surface hydrophobicity. In addition, the in vitro allergenicity of the Ara h 2-PA2 complex was investigated using enzyme-linked immunosorbent assay (ELISA) kits. The immunoglobulin E (IgE) binding capacity of Ara h 2, as well as the release of allergenic cytokines, decreased after interacting with PA2. When the ratio of Ara h 2-to-PA2 was 1:50, the IgE binding capacity was reduced by around 43 %. This study provides valuable insights into the non-covalent interactions between Ara h 2 and PA2, as well as the potential mechanism of action of the anti-allergic reaction caused by binding of the polyphenols to the allergens.

Local Sources of Protein in Low- and Middle-Income Countries: How to Improve the Protein Quality?

Protein inadequacy is a major contributor to nutritional deficiencies and adverse health outcomes of populations in low- and middle-income countries (LMICs). People in LMICs often consume a diet predominantly based on staple crops, such as cereals or starches, and derive most of their daily protein intakes from these sources. However, plant-based sources of protein often contain low levels of indispensable amino acids (IAAs). Inadequate intake of IAA in comparison with daily requirements is a limiting factor that results in protein deficiency, consequently in the long-term stunting and wasting. In addition, plant-based sources contain factors such as antinutrients that can diminish protein digestion and absorption. This review describes factors that affect protein quality, reviews dietary patterns of populations in LMICs and discusses traditional and novel small- and large-scale techniques that can improve the quality of plant protein sources for enhanced protein bioavailability and digestibility as an approach to tackle malnutrition in LMICs. The more accessible small-scale food-processing techniques that can be implemented at home in LMICs include soaking, cooking, and germination, whereas many large-scale techniques must be implemented on an industrial level such as autoclaving and extrusion. Limitations and considerations to implement those techniques locally in LMICs are discussed. For instance, at-home processing techniques can cause loss of nutrients and contamination, whereas limitations with larger scale techniques include high energy requirements, costs, and safety considerations. This review suggests that combining these small- and large-scale approaches could improve the quality of local sources of proteins, and thereby address adverse health outcomes, particularly in vulnerable population groups such as children, adolescents, elderly, and pregnant and lactating women.

Desensitization and remission after peanut sublingual immunotherapy in 1- to 4-year-old peanut-allergic children: A randomized, placebo-controlled trial

BACKGROUND

Prior studies of peanut sublingual immunotherapy (SLIT) have suggested a potential advantage with younger age at treatment initiation.

OBJECTIVE

We studied the safety and efficacy of SLIT for peanut allergy in 1- to 4-year-old children.

METHODS

Peanut-allergic 1- to 4-year-old children were randomized to receive 4 mg peanut SLIT versus placebo. Desensitization was assessed by double-blind, placebo-controlled food challenge (DBPCFC) after 36 months of treatment. Participants desensitized to at least 443 mg peanut protein discontinued therapy for 3 months and then underwent DBPCFC to assess for remission. Biomarkers were measured at baseline and longitudinally during treatment.

RESULTS

Fifty participants (25 peanut SLIT, 25 placebo) with a median age of 2.4 years were enrolled across 2 sites. The primary end point of desensitization was met with actively treated versus placebo participants having a significantly greater median cumulative tolerated dose (4443 mg vs 143 mg), higher likelihood of passing the month 36 DBPCFC (60% vs 0), and higher likelihood of demonstrating remission (48% vs 0). The highest rate of desensitization and remission was seen in 1- to 2-year-olds, followed by 2- to 3-year-olds and 3- to 4-year-olds. Longitudinal changes in peanut skin prick testing, peanut-specific IgG4, and peanut-specific IgG4/IgE ratio were seen in peanut SLIT but not placebo participants. Oropharyngeal itching was more commonly reported by peanut SLIT than placebo participants. Skin, gastrointestinal, upper respiratory, lower respiratory, and multisystem adverse events were similar between treatment groups.

CONCLUSION

Peanut SLIT safely induces desensitization and remission in 1- to 4-year-old children, with improved outcomes seen with younger age at initiation.

Development and evaluation of mouse anti-Ara h 1 and Ara h 3 IgE monoclonal antibodies for advancing peanut allergy research

Immediate hypersensitivity reactions to peanuts are a considerable public health concern due to the acute and severe IgE mediated reactions. To conduct research on the pathogenesis and therapeutics of peanut allergies, it is imperative to have mouse anti-crude peanut extract (CPE) IgE monoclonal antibodies (mAbs) for both in-vitro and in-vivo assays. Without these tools, it is difficult to advance research in this field. In this study, four hybridomas producing anti-CPE IgE mAbs were developed and the IgE mAbs were validated using immune-blot analysis, Sandwich ELISA, Indirect ELISA, a cell-based assay using RBL-2H3 cells, and footpad type I hypersensitivity reaction studies in mice. The results indicate that two of the four mAbs can be effectively used for both in-vitro and in-vivo peanut allergy studies, as they induce allergic reactions with sensitization alone in mice. These novel anti-Ara h1 and Ara h 3 IgE mAbs, in combination with the detailed protocols outlined in this article, offer valuable guidance for studying acute allergic reactions involving mast cells across various platforms. With some considerations, the IgE mAbs can significantly advance peanut allergy research.

Retrospective Analysis of Allergen Distribution Dynamics in Central Taiwan

Introduction: Allergy is a type Ⅰ hypersensitivity reaction to certain substances (allergens) such as environmental factors, food and drugs. Allergies are a significant public health issue, and therefore, understanding the distribution patterns of allergens in specific regions is important. This study aimed to retrospectively analyse allergen distribution patterns in Central Taiwan over a 5 years period (2018-2022). Methods: Data of patients who had allergen sensitization testing using the OPTIGEN® Allergen-Specific IgE Assay from the 1st of January 2018 to the 31st of December 2022 were reviewed retrospectively. Statistical analyses were performed to determine the prevalence and distribution of allergens in our study population. Results: A total of 8,444 patients (3,784 males and 4,660 females) who attended the Asia University Hospital for allergen detection were enrolled in this study. Dermatophagoides farina (41.8%), Dermatophagoides pteronyssinus (37.9%), house dust (24.6%), cockroach mix (17.7%), crab (12.6%), clam (9.8%), shrimp (9.1%), cat dander (8.1%), pig weed (8%) and peanut (7.8%) were identified as the ten allergens that most commonly induced sensitization in our study population. Additionally, crab, clam, shrimp, peanut and beef were the five most common food allergens. Conclusion: In summary, our findings contribute significantly to the knowledge on allergen distribution in Central Taiwan. Our identification of prevalent allergens may contribute to an improved understanding of the epidemiology of allergies in this region.

Invariant NKT cells are more abundant in peanut-allergic adults and a subset of CD8+ iNKT cells are depleted after peanut oil exposure

Introduction

Peanut allergy is one of the most prevalent food allergies globally. Currently, most research into the mechanisms involved in protein allergy focuses on the protein allergens under investigation, and information on the function of accompanying compounds, such as lipids, is scarce. Thus, this research investigates the role of peanut-associated lipids and invariant natural killer T (iNKT) cells in peanut allergy using a novel, human, in vitro assay.

Methods

PBMCs from non-allergic and peanut-allergic subjects were stimulated with the glycolipid, α-Galactosylceramide (α-GalCer), over 14 days for iNKT cell expansion. Autologous dendritic cells (DCs) were stimulated with either peanut oil, the lipid-binding peanut allergen, Ara h 8, or both peanut oil and Ara h 8. The expanded iNKT cells were then immunomagnetically isolated and co-cultured for 5 h with autologous DCs, and cytokine expression was measured by flow cytometry.

Results

A 5-fold higher iNKT cell population was observed in peanut-allergic subject peripheral blood compared to non-allergic controls. In all subjects, conventional flow analysis highlighted iNKTs co-cultured with autologous α-GalCer-pulsed DCs displayed increased IL-4 and IFN-y secretion within 5 hours of co-culture. A 10-parameter unsupervised clustering analysis of iNKT phenotype found significantly more CD3+CD8+CD25+IL-4+IL-5+IL-10+IFNγ+ cells in non-allergic adults following culture with peanut oil.

Conclusion

For the first time, we show iNKT cells are more abundant in peanut-allergic adults compared to non-allergic adults, and peanut lipid-exposed iNKT cells resulted in the identification of a subset of CD8+ iNKT cells which was significantly lower in peanut-allergic adults. Thus, this study proposes a role for iNKT cells and peanut allergen-associated lipids in peanut allergy.

Oral Immunotherapy for Peanut Allergy in Children 1 to Less Than 4 Years of Age

BACKGROUND: Peanut allergy is a common childhood allergy, and the only approved treatment for children 4 to 17 years of age is peanut allergen powder-dnfp (PTAH) oral immunotherapy. METHODS: For this phase 3, randomized, double-blind, placebo-controlled trial, we enrolled peanut-allergic children 1 to <4 years of age who experienced dose-limiting symptoms from ≤300 mg peanut protein during a screening double-blind, placebo-controlled food challenge (DBPCFC). Participants received PTAH or placebo, randomized in a 2:1 ratio, for approximately 12 months. At the trial conclusion, all participants underwent an exit BDPCFC. The primary end point was desensitization (i.e., tolerating a ≥600-mg single dose of peanut protein with only mild allergy symptoms). RESULTS: In the PTAH-treated group (n=98), 73.5% of participants tolerated a single dose of ≥600 mg peanut protein at exit DBPCFC compared with 6.3% in the placebo group (n=48). Most participants experienced an adverse event (98.0% of PTAH-treated and 97.9% of placebo-treated participants), which was mild or moderate in grade for 93.2% of participants (92.9% in PTAH-treated and 93.8% in placebo-treated participants). Treatment-related adverse events, which were mild to moderate, were experienced by 75.5% of PTAH-treated and 58.3% of placebo-treated participants. Three treatment-related systemic allergic reactions, none of which were severe or serious in grade, were noted in two PTAH-treated participants (2%). CONCLUSIONS: In peanut-allergic children 1 to <4 years of age treated with PTAH for approximately 12 months, the majority tolerated all peanut protein dose levels assessed. PTAH-treated patients had more treatment-related adverse events, which were mild to moderate severity. (Funded by Aimmune Therapeutics; ClinicalTrials.gov number, NCT03736447.)

The epithelial barrier: The gateway to allergic, autoimmune, and metabolic diseases and chronic neuropsychiatric conditions

Since the 1960 s, our health has been compromised by exposure to over 350,000 newly introduced toxic substances, contributing to the current pandemic in allergic, autoimmune and metabolic diseases. The "Epithelial Barrier Theory" postulates that these diseases are exacerbated by persistent periepithelial inflammation (epithelitis) triggered by exposure to a wide range of epithelial barrier-damaging substances as well as genetic susceptibility. The epithelial barrier serves as the body's primary physical, chemical, and immunological barrier against external stimuli. A leaky epithelial barrier facilitates the translocation of the microbiome from the surface of the afflicted tissues to interepithelial and even deeper subepithelial locations. In turn, opportunistic bacterial colonization, microbiota dysbiosis, local inflammation and impaired tissue regeneration and remodelling follow. Migration of inflammatory cells to susceptible tissues contributes to damage and inflammation, initiating and aggravating many chronic inflammatory diseases. The objective of this review is to highlight and evaluate recent studies on epithelial physiology and its role in the pathogenesis of chronic diseases in light of the epithelial barrier theory.

Epithelial Barrier Theory: The Role of Exposome, Microbiome, and Barrier Function in Allergic Diseases

Allergic diseases are a major public health problem with increasing prevalence. These immune-mediated diseases are characterized by defective epithelial barriers, which are explained by the epithelial barrier theory and continuously emerging evidence. Environmental exposures (exposome) including global warming, changes and loss of biodiversity, pollution, pathogens, allergens and mites, laundry and dishwasher detergents, surfactants, shampoos, body cleaners and household cleaners, microplastics, nanoparticles, toothpaste, enzymes and emulsifiers in processed foods, and dietary habits are responsible for the mucosal and skin barrier disruption. Exposure to barrier-damaging agents causes epithelial cell injury and barrier damage, colonization of opportunistic pathogens, loss of commensal bacteria, decreased microbiota diversity, bacterial translocation, allergic sensitization, and inflammation in the periepithelial area. Here, we review scientific evidence on the environmental components that impact epithelial barriers and microbiome composition and their influence on asthma and allergic diseases. We also discuss the historical overview of allergic diseases and the evolution of the hygiene hypothesis with theoretical evidence.

Early Peanut Immunotherapy in Children (EPIC) trial: protocol for a pragmatic randomised controlled trial of peanut oral immunotherapy in children under 5 years of age

INTRODUCTION

Food allergy is a major public health challenge in Australia. Despite widespread uptake of infant feeding and allergy prevention guidelines the incidence of peanut allergy in infants has not fallen, and prevalence of peanut allergy in school-aged children continues to rise. Therefore, effective and accessible treatments for peanut allergy are required. There is high-quality evidence for efficacy of oral immunotherapy in children aged 4-17 years old; however, few randomised trials have investigated peanut oral immunotherapy (OIT) in young children. Furthermore, the use of food products for OIT with doses prepared and administered by parents without requiring pharmacy compounding has the potential to reduce costs associated with the OIT product.

METHODS AND ANALYSIS

Early Peanut Immunotherapy in Children is an open-label randomised controlled trial of peanut OIT compared with standard care (avoidance) to induce desensitisation in children aged 1-4 years old with peanut allergy. n=50 participants will be randomised 1:1 to intervention (daily peanut OIT for 12 months) or control (peanut avoidance). The primary outcome is the proportion of children in each group with a peanut eliciting dose >600 mg peanut protein as assessed by open peanut challenge after 12 months, analysed by intention to treat. Secondary outcomes include safety as assessed by frequency and severity of treatment-related adverse events, quality of life measured using age-appropriate food allergy-specific questionnaires and immunological changes during OIT.

ETHICS

The trial is approved by the Child and Adolescent Health Service Human Research Ethics Committee and prospectively registered with the Australia and New Zealand Clinical Trials Registry.

DISSEMINATION

Trial outcomes will be published in a peer-review journal and presented and local and national scientific meetings.

TRIAL REGISTRATION NUMBER

ACTRN12621001001886.

Immune signatures predicting the clinical outcome of peanut oral immunotherapy: where we stand

Peanut allergy is a growing health concern that can cause mild to severe anaphylaxis as well as reduced quality of life in patients and their families. Oral immunotherapy is an important therapeutic intervention that aims to reshape the immune system toward a higher threshold dose reactivity and sustained unresponsiveness in some patients. From an immunological point of view, young patients, especially those under 3 years old, seem to have the best chance for therapy success. To date, surrogate markers for therapy duration and response are evasive. We provide a comprehensive overview of the current literature state regarding immune signatures evolving over the course of oral immunotherapy as well as baseline immune conditions prior to the initiation of treatment. Although research comparing clinical and immune traits in the first years of life vs. later stages across different age groups is limited, promising insights are available on immunological endotypes among peanut-allergic patients. The available data call for continued research to fill in gaps in knowledge, possibly in an integrated manner, to design novel precision health approaches for advanced therapeutic interventions in peanut allergy.

Association of Reaction Symptoms and Eliciting Dose With Health-Related Quality of Life in Children With Peanut Allergy

BACKGROUND

Food allergy adversely affects the health-related quality of life (HRQoL) of patients. It is unclear whether factors such as the reaction eliciting dose (ED) and the nature of allergic reaction symptoms affect HRQoL.

OBJECTIVE

To explore associations between reaction ED or the nature of allergic symptoms and HRQoL among children with peanut allergy.

METHODS

This study was a secondary analysis of baseline data from the PPOIT-003 randomized trial in 212 children aged 1 to 10 years with challenge-confirmed peanut allergy. Children's past reaction symptoms were collected by clinicians during screening. Associations between variables of interest and parent-reported child-proxy HRQoL were examined by univariable and multivariable linear regression.

RESULTS

Mean age of study participants was 5.9 years; 63.2% were male. Children with a low reaction ED of 80 mg peanut protein had significantly poorer HRQoL (β = -0.81; 95% CI, -1.61 to -0.00; P = .049) compared with children with a high ED of 2,500 mg peanut protein. Gastrointestinal symptoms (β = 0.45; 95% CI, 0.03-0.87; P = .037), lower airway symptoms (β = 0.46; 95% CI, 0.05-0.87; P = .030), multisystem involvement (β = 0.71; 95% CI, 0.25-1.16; P = .003), or anaphylaxis (β = 0.46; 95% CI, 0.04-0.87; P = .031) during a previous reaction were associated with worse HRQoL.

CONCLUSIONS

Peanut-allergic children with a lower allergen reaction threshold experienced a greater negative HRQoL impact compared with children with higher reaction thresholds. In addition, specific past allergic reaction symptoms were associated with comparatively worse HRQoL. Children experiencing these symptoms and those with lower reaction ED require increased clinical support to manage the food allergy and are likely to benefit from interventions that can improve HRQoL.

Research Advances in the High-Value Utilization of Peanut Meal Resources and Its Hydrolysates: A Review

Peanut meal (PM) is a by-product of extracting oil from peanut kernels. Although peanut meal contains protein, carbohydrates, minerals, vitamins, and small amounts of polyphenols and fiber, it has long been used as a feed in the poultry and livestock industries due to its coarse texture and unpleasant taste. It is less commonly utilized in the food processing industry. In recent years, there has been an increasing amount of research conducted on the deep processing of by-products from oil crops, resulting in the high-value processing and utilization of by-products from various oil crops. These include peanut meal, which undergoes treatments such as enzymatic hydrolysis in industries like food, chemical, and aquaculture. The proteins, lipids, polyphenols, fibers, and other components present in these by-products and hydrolysates can be incorporated into products for further utilization. This review focuses on the research progress in various fields, such as the food processing, breeding, and industrial fields, regarding the high-value utilization of peanut meal and its hydrolysates. The aim is to provide valuable insights and strategies for maximizing the utilization of peanut meal resources.

No evidence of isotretinoin sensitization in peanut-allergic children: a cross-sectional study

The European Medicines Agency (EMA) advises that all medicines containing soya-derived excipients should be labelled as contraindicated in peanut-allergic individuals. This is despite evidence of very little cross-reactivity between soya and peanut allergies. It is highly unlikely that patients with peanut allergy are at risk of a cross-reactive soya oil-based allergic reaction to soya protein in isotretinoin. This cross-sectional study has demonstrated the absence of IgE-sensitization to isotretinoin in peanut-allergic children and adolescents. Isotretinoin does not need to be avoided by peanut-allergic patients and we would encourage the EMA to alter their advice regarding soybean oil-containing medications to reflect this.

Long-term safety and immunologic outcomes of daily oral immunotherapy for peanut allergy

Background

Oral immunotherapy containing peanut (Arachis hypogaea) allergen powder-dnfp (PTAH) (Palforzia [Aimmune Therapeutics, Brisbane, Calif]) for 9 to 12 months resulted in higher tolerated amounts of peanut protein in PTAH-treated individuals aged 4 to 17 years with peanut allergy than in placebo-treated participants.

Objective

We aimed to describe additional long-term pooled safety data and changes in peanut sensitization markers from baseline through approximately 5 years of treatment.

Methods

The results from 6 clinical trials of PTAH (3 controlled and 3 open-label extension studies [N = 1227]) were pooled, and analysis of safety outcomes and immunologic data was performed. The PTAH doses were administered sequentially as follows: initial dose escalation (dose increased to 6 mg over 2 days), updosing (dose increased every 2 weeks to 300 mg for a minimum of 6 months), and maintenance dosing (300 mg per day).

Results

There was a trend toward decreased adverse events (AEs) at years 1 and 2 that was maintained up to 5 years, with 94% of patients experiencing mild or moderate AEs and only 13% discontinuing PTAH use because of AEs overall. Gastrointestinal symptoms were the most commonly reported treatment-related AEs. A downward trend in systemic allergic reactions was also reported. PTAH treatment resulted in reduced levels of peanut-specific IgE after the first year and increased levels of peanut-specific IgG4, with a lowered peanut-specific IgE:IgG4 ratio. A reduction in median peanut skin prick test wheal diameter was observed (11.50 mm at baseline vs 5.75 mm at year 5).

Conclusion

Long-term immunomodulation without any new safety signals was reported with PTAH immunotherapy in the largest safety data set and longest treatment duration for oral immunotherapy published to date.

Low-Dose Oral Challenge Test in Pediatric Patients With Peanut Allergy: Tolerance Assessment of a Trace 5 mg Peanut Test After Symptom Induction With a 500 mg Test

Introduction Peanut allergy (PA) represents a significant public health concern, particularly prevalent in Western countries. Children at high risk for PA may undergo a low-dose oral food challenge (OFC). However, if the result is positive, complete elimination of peanuts from the diet is recommended, and further trace OFC is typically not performed.  Material and methods This cross-sectional study retrospectively examined the rate of positive peanut OFC with a total peanut load of 5 mg in children who tested positive with a total peanut load of 500 mg. Patient information was gathered from medical records. The primary endpoint was the rate at which children who tested positive in the OFC with 500 mg of peanut butter also tested positive with 5 mg of peanut butter equivalent.  Results Among 32 children who underwent an OFC with a total peanut load of 500 mg, two were excluded for not meeting the criteria. Among the remaining 30 children, 14 (46.7%) had a positive 500 mg peanut OFC test, and three (10%) experienced an anaphylactic reaction. Those who tested positive for the OFC had higher peanut-specific and Ara h2-specific immunoglobulin E (IgE) antibodies. An OFC with 5 mg of peanuts performed on 10 of the 14 patients who tested positive for 500 mg of peanuts showed no positive results. Conclusion The results of this study suggest that children with severe PA who exhibit positive symptoms to a total peanut load of 500 mg can tolerate a 5 mg dose of peanuts and should be considered for an OFC.

K-means cluster analysis of characteristic patterns of allergen in different ages: Real life study

BACKGROUND

Atopy varies in people of different ages owing to different physical conditions and exposure to allergens. We aimed to cluster ages based on atopic severity using K-means cluster analysis and identify atopic incidence, severity, as well as the association among peripheral eosinophils, IgE and sensitisation.

METHODS

Consecutive patients (n = 7654) with allergic symptoms and undergoing allergen-specific IgE tests were included from 2013 to 2017. Age, sex, specific-IgE, peripheral eosinophil counts and total-IgE were collected.

RESULTS

Five age categories were identified: 1-17, 18-36, 37-52, 53-69 and 70-100 years. The incidences of atopy and poly-sensitisation decreased with increasing age. Similar trend was observed for aeroallergens, egg and milk but not for peanuts, soy or seafood. Dust mites remain the crucial factor bothering patients with allergic symptoms, especially for children and adolescents. In patients aged <52 years, sensitisation to aeroallergens was more prevalent than food. In group 37-52 years, incidence of females' atopy was higher than that of males. The overlap of atopy, high eosinophils, and high total-IgE was found in only 19.18% of patients. The trend of allergen-test positivity is not parallel to total IgE and peripheral eosinophil counts.

CONCLUSION

Age-grouping based on cluster analysis helps to find the changes in atopic status and distribution of sensitised allergens with age. Allergen tests are still necessary in the clinical diagnosis and treatment. An innovative exploration of the influence of age and allergens on total-IgE and eosinophil counts is helpful for the development of bio-targeted precision therapy.

CLINICAL TRIAL REGISTRATION

ChiCTR2300067700.

Open-label study of the efficacy, safety, and durability of peanut sublingual immunotherapy in peanut-allergic children

BACKGROUND

Studies on the efficacy of peanut sublingual immunotherapy (SLIT) are limited. The durability of desensitization after SLIT has not been well described.

OBJECTIVE

We sought to evaluate the efficacy and safety of 4-mg peanut SLIT and persistence of desensitization after SLIT discontinuation.

METHODS

Challenge-proven peanut-allergic 1- to 11-year-old children were treated with open-label 4-mg peanut SLIT for 48 months. Desensitization after peanut SLIT was assessed by a 5000-mg double-blind, placebo-controlled food challenge (DBPCFC). A novel randomly assigned avoidance period of 1 to 17 weeks was followed by the DBPCFC. Skin prick test results immunoglobulin levels, basophil activation test results, TH1, TH2, and IL-10 cytokines were measured longitudinally. Safety was assessed through patient-reported home diaries.

RESULTS

Fifty-four participants were enrolled and 47 (87%) completed peanut SLIT and the 48-month DBPCFC per protocol. The mean successfully consumed dose (SCD) during the DBPCFC increased from 48 to 2723 mg of peanut protein after SLIT (P < .0001), with 70% achieving clinically significant desensitization (SCD > 800 mg) and 36% achieving full desensitization (SCD = 5000 mg). Modeled median time to loss of clinically significant desensitization was 22 weeks. Peanut skin prick test; peanut-specific IgE, IgG4, and IgG4/IgE ratio; and peanut-stimulated basophil activation test, IL-4, IL-5, IL-13, IFN-γ, and IL-10 changed significantly compared with baseline, with changes seen as early as 6 months. Median rate of reaction per dose was 0.5%, with transient oropharyngeal itching being the most common, and there were no dosing symptoms requiring epinephrine.

CONCLUSIONS

In this open-label, prospective study, peanut SLIT was safe and induced clinically significant desensitization in most of the children, lasting more than 17 weeks after discontinuation of therapy.

Risk Factors for Anaphylaxis in Children Allergic to Peanuts

Background and Objectives: A peanut allergy is the most common single cause of anaphylaxis in children. The risk factors for anaphylaxis in children with a peanut allergy are not well defined. Therefore, we aimed to identify epidemiological, clinical, and laboratory characteristics of children with a peanut allergy that may predict the severity of the allergic reaction and anaphylaxis. Materials and Methods: We conducted a cross-sectional study and included 94 children with a peanut allergy. Allergy testing was performed, including skin prick testing and the determination of specific IgE levels to peanuts and their Ara h2 component. In case of discordance between patient history and allergy testing, an oral food challenge with peanuts was performed. Results: Anaphylaxis and moderate and mild reactions to peanuts occurred in 33 (35.1%), 30 (31.9%), and 31 (33.0%) patients, respectively. The severity of the allergic reaction was only weakly correlated (p = 0.04) with the amount of peanuts consumed. The median number of allergic reactions to peanuts was 2 in children with anaphylaxis compared to 1 in other patients (p = 0.04). The median level of specific IgE to Ara h2 was 5.3 IU/mL in children with anaphylaxis compared to 0.6 IU/mL and 10.3 IU/mL in children with mild and moderate peanut allergies (p = 0.06). The optimal cutoff for distinguishing between anaphylaxis and a less severe allergic reaction to peanuts was a specific IgE Ara h2 level of 0.92 IU/mL with 90% sensitivity and 47.5% specificity for predicting anaphylaxis (p = 0.04). Conclusions: Epidemiological and clinical characteristics of the patient cannot predict the severity of the allergic reaction to peanuts in children. Even standard allergy testing, including component diagnostics, is a relatively poor predictor of the severity of an allergic reaction to peanuts. Therefore, more accurate predictive models, including new diagnostic tools, are needed to reduce the need for oral food challenge in most patients.

Antioxidant Properties of Protein-Rich Plant Foods in Gastrointestinal Digestion—Peanuts as Our Antioxidant Friend or Foe in Allergies

Thermally processed peanuts are ideal plant models for studying the relationship between allergenicity and antioxidant capacity of protein-rich foods, besides lipids, carbohydrates and phytochemicals. Peanut is highly praised in the human diet; however, it is rich in allergens (>75% of total proteins). One-third of peanut allergens belong to the products of genes responsible for the defence of plants against stress conditions. The proximate composition of major peanut macromolecules and polyphenols is reviewed, focusing on the identity and relative abundance of all peanut proteins derived from recent proteomic studies. The importance of thermal processing, gastrointestinal digestion (performed by INFOGEST protocol) and their influence on allergenicity and antioxidant properties of protein-rich plant food matrices is elaborated. Antioxidant properties of bioactive peptides from nuts were also considered. Moreover, there are no studies dealing simultaneously with the antioxidant and allergenic properties of protein- and polyphenol-rich foods, considering all the molecules that can significantly contribute to the antioxidant capacity during and after gastrointestinal digestion. In summary, proteins and carbohydrates are underappreciated sources of antioxidant power released during the gastrointestinal digestion of protein-rich plant foods, and it is crucial to decipher their antioxidant contribution in addition to polyphenols and vitamins before and after gastrointestinal digestion.

Peanut Allergenicity: An Insight into Its Mitigation Using Thermomechanical Processing

Peanuts are the seeds of a legume crop grown for nuts and oil production. Peanut allergy has gained significant attention as a public health issue due to its increasing prevalence, high rate of sensitization, severity of the corresponding allergic symptoms, cross-reactivity with other food allergens, and lifelong persistence. Given the importance of peanuts in several sectors, and taking into consideration the criticality of their high allergic potential, strategies aiming at mitigating their allergenicity are urgently needed. In this regard, most of the processing methods used to treat peanuts are categorized as either thermal or thermomechanical techniques. The purpose of this review is to provide the reader with an updated outlook of the peanut’s allergens, their mechanisms of action, the processing methods as applied to whole peanuts, as well as a critical insight on their impact on the allergenicity. The methods discussed include boiling, roasting/baking, microwaving, ultrasonication, frying, and high-pressure steaming/autoclaving. Their effectiveness in alleviating the allergenicity, and their capacity in preserving the structural integrity of the treated peanuts, were thoroughly explored. Research data on this matter may open further perspectives for future relevant investigation ultimately aiming at producing hypoallergenic peanuts.

Post hoc analysis examining symptom severity reduction and symptom absence during food challenges in individuals who underwent oral immunotherapy for peanut allergy: results from three trials

PURPOSE

Peanut allergy and its current management, involving peanut avoidance and use of rescue medication during instances of accidental exposure, are burdensome to patients and their caregivers and can be a source of stress, uncertainty, and restriction. Physicians may also be frustrated with a lack of effective and safe treatments other than avoidance in the current management of peanut allergy. Efficacy, determined using double-blind, placebo-controlled food challenges (DBPCFCs), of oral immunotherapy with peanut (Arachis hypogaea) allergen powder-dnfp (PTAH; Palforzia^®) was demonstrated versus placebo in children and adolescents aged 4 to 17 years in multiple phase 3 trials; continued benefit of PTAH was shown in a follow-on trial. The DBPCFC is a reproducible, rigorous, and clinically meaningful assessment accepted by regulatory authorities to evaluate the level of tolerance as an endpoint for accidental exposures to peanut in real life. It also provides useful clinical and patient-relevant information, including the amount of peanut protein an individual with peanut allergy can consume without experiencing dose-limiting symptoms, severity of symptoms, and organs affected upon ingestion of peanut protein. We explored symptoms of peanut exposure during DBPCFCs from phase 3 and follow-on trials of PTAH to further characterize treatment efficacy from a perspective relevant to patients, caregivers, and clinicians.

METHODS

Symptom data recorded during screening and/or exit DBPCFCs from participants aged 4 to 17 years receiving PTAH or placebo were examined post hoc across three PTAH trials (PALISADE [ARC003], ARC004 [PALISADE follow-on], and ARTEMIS [ARC010]). The maximum peanut protein administered as a single dose during DBPCFCs was 1000 mg (PALISADE and ARTEMIS) and 2000 mg (ARC004). Symptoms were classified by system organ class (SOC) and maximum severity. Endpoints were changes in symptom severity and freedom from symptoms (ie, asymptomatic) during DBPCFC. Relative risk (RR) was calculated for symptom severity by SOC and freedom from symptoms between groups; descriptive statistics were used to summarize all other data.

RESULTS

The risk of any respiratory (RR 0.42 [0.30-0.60], P < 0.0001), gastrointestinal (RR 0.34 [0.26-0.44], P < 0.0001), cardiovascular/neurological (RR 0.17 [0.08-0.39], P < 0.001), or dermatological (RR 0.33 [0.22-0.50], P < 0.0001) symptoms was significantly lower in participants treated with PTAH versus placebo upon exposure to peanut at the end of the PALISADE trial (ie, exit DBPCFC). Compared with placebo-treated participants (23.4%), the majority (76.3%) of PTAH-treated participants had no symptoms at the exit DBPCFC when tested at the peanut protein dose not tolerated (ie, reactive dose) during the screening DBPCFC. Significantly higher proportions of PTAH-treated participants were asymptomatic at doses ≤ 100 mg in the exit DBPCFC compared with placebo-treated participants (PALISADE: 69.35% vs 12.10%, RR 5.73 [95% confidence interval (CI) 3.55-9.26]; P < 0.0001; ARTEMIS: 67.42% vs 13.95%, RR 4.83 [95% CI 2.28-10.25]; P < 0.0001); findings were similar at peanut protein doses ≤ 1000 mg (PALISADE: RR 15.56 [95% CI 5.05-47.94]; P < 0.0001; ARTEMIS: RR 34.74 [95% CI 2.19-551.03]; P < 0.0001). In ARC004, as the period of PTAH maintenance became longer, greater proportions of participants were asymptomatic at doses of peanut protein ≤ 1000 mg in the exit DBPCFC (from 37.63% after ~ 6 months of maintenance treatment [exit DBPCFC of PALISADE] to 45.54% after ~ 13 months and 58.06% after ~ 20 months of overall PTAH maintenance treatment).

CONCLUSIONS

PTAH significantly reduced symptom severity due to exposure to peanut, which is clinically relevant. When exposed to peanut, participants with peanut allergy treated with PTAH rarely had moderate or severe respiratory or cardiovascular/neurological symptoms. Oral immunotherapy with PTAH appears to reduce frequency and severity of allergic reactions in individuals with peanut allergy after accidental exposure to peanut and may enable them and their families to have an improved quality of life. Trial registration ClinicalTrials.gov, NCT02635776, registered 17 December 2015, https://clinicaltrials.gov/ct2/show/NCT02635776?term=AR101&draw=2&rank=7 ; ClinicalTrials.gov, NCT02993107, registered 08 December 2016, https://clinicaltrials.gov/ct2/show/NCT02993107?term=AR101&draw=2&rank=6 ; ClinicalTrials.gov, NCT03201003, registered 22 June 2017, https://clinicaltrials.gov/ct2/show/NCT03201003 ? term = AR101&draw = 2&rank = 9.

Allergenicity of peanut allergens and its dependence on the structure

Food allergies are a global food safety problem. Peanut allergies are common due, in part, to their popular utilization in the food industry. Peanut allergy is typically an immunoglobulin E-mediated reaction, and peanuts contain 17 allergens belonging to different families in peanut. In this review, we first introduce the mechanisms and management of peanut allergy, followed by the basic structures of associated allergens. Subsequently, we summarize methods of epitope localization for peanut allergens. These methods can be instrumental in speeding up the discovery of allergenicity-dependent structures. Many attempts have been made to decrease the allergenicity of peanuts. The structures of hypoallergens, which are manufactured during processing, were analyzed to strengthen the desensitization process and allergen immunotherapy. The identification of conformational epitopes is the bottleneck in both peanut and food allergies. Further, the identification and modification of such epitopes will lead to improved strategies for managing and preventing peanut allergy. Combining traditional wet chemistry research with structure simulation studies will help in the epitopes' localization.