Peanut oral immunotherapy is not ready for clinical use

Food immunotherapy practice: Nation differences across Europe, the FIND project

BACKGROUND

Food allergen immunotherapy (FA-AIT) practice is known to vary globally. This project aims to identify and characterize European centres performing FA-AIT.

METHODS

An EAACI task force conducted an online survey to gather relevant information regarding FA-AIT practice and setting-specific resources after reviewing the published literature and congress abstracts throughout Europe.

RESULTS

We identified 102 FA-AIT centres in 18 countries; only Spain (n = 39) and France (n = 16) had ≥10 such centres. Overall, most facilities were hospital-based (77.5%), publicly funded (80.4%) and delivered FA-AIT as routine clinical care (80.4%). On average, departments had 3 allergists/paediatric allergists and 2 nurses. Surveyed centres had provided FA-AIT for a median of 9 years [1-24] to a median of 105 [5-2415] patients. The estimated total number of treated patients was 24875, of whom 41.3% received AIT for milk, 34.2% egg, 12.8% peanut and 11.7% other foods. Anaphylaxis to AIT doses requiring over 4-6 h of observation was reported by 70.6% of centres, ICU admissions by 10.8% and eosinophilic esophagitis by 45.1%. Quality of life and sustained unresponsiveness were evaluated in 20.6% and 54.9% of centres, respectively. The main contraindications for food AIT were severe asthma (57%-63%), eosinophilic esophagitis (56%-48%) and age below 5 years (47%-41%).

CONCLUSIONS

In Europe, FA-AIT is provided mostly in clinical practice. Significant variation is seen in the number of centres per country, facility characteristics and inclusion/exclusion criteria, and in certain aspects of protocols. Potential inequality in access to AIT has been identified as well as the need for education and guidance for treatment standardization.

Evaluation of baked egg oral immunotherapy in French children with hen's egg allergy

BACKGROUND

Introduction and gradual incremental escalation of a low dose of baked egg may accelerate the resolution of severe hen's egg (HE) allergy for some children. The purpose of our study was to evaluate the efficacy and safety of baked egg oral immunotherapy (OIT) in children with HE allergy after a low-dose baked egg oral food challenge (OFC).

METHODS

In a retrospective analysis of OFC performed between 2013 and 2018 at the Children's Hospital of Toulouse (France), we identified 71 children with HE allergy and high egg-white (EW) and ovomucoid specific IgE levels, who underwent a total of 164 OFC (71 baked egg, then 93 unbaked egg). Mean age at first low-dose baked egg OFC was 6 years. Median EW specific IgE was 14.0 kUA/L, and median ovomucoid specific IgE was 11.7 kUA/L.

RESULTS

Most children were treated with baked egg OIT. Our study shows that 78.9% of the children did not react to first low-dose baked egg OFC (702 mg of HE protein). 8.7% of children discontinued OIT at home. Finally, desensitization to unbaked HE was achieved in 47 children (66.2% of children allergic to HE). Children with lower EW specific IgE levels had a significantly higher probability of becoming desensitized to HE. We did not report any anaphylactic reactions to baked egg OIT.

CONCLUSION

Most children with HE allergy and high egg-white (EW) and ovomucoïd specific IgE levels tolerate the introduction of baked egg. Baked egg OIT is safe, and anaphylaxis to baked egg OIT has not been observed.

How to Incorporate Oral Immunotherapy into Your Clinical Practice

PURPOSE OF REVIEW

The purpose of this review is to discuss how to best incorporate oral immunotherapy into your clinical practice based on recent evidence and guidelines, and address controversies.

RECENT FINDINGS

Oral immunotherapy is the food immunotherapy treatment with the most literature supporting its use. Recent data from both randomized clinical trials and real-world studies show OIT is especially safe and effective in preschoolers, while avoidance may be less safe than previously thought. OIT guidelines support its use outside of research. Oral immunotherapy can be safely and effectively incorporated into your clinical practice, with careful planning and consideration of scenarios where benefits outweigh risks. Baseline oral food challenges are necessary in clinical trials, but in clinical practice, these are best done when the history is unclear due to resource limitations. There is a role for both regular food and FDA-approved products. Future research should focus on optimizing safety and adherence in the real-world setting.

Oral Immunotherapy for Food Allergy-a US Regulatory Perspective

The recent approval of Palforzia for treatment of peanut allergy by the US Food and Drug Administration (USFDA) predicts that additional products for oral immunotherapy (OIT) are on the horizon. In this article, the authors review the legal framework by which the USFDA regulates products for OIT of food allergy and the clinical data that demonstrated that the safety and effectiveness profile of Palforzia supported approval and conclude with a discussion of oral food challenge (OFC) as a clinical endpoint to demonstrate safety and effectiveness of OIT products.

Oral immunotherapy for peanut allergy (PACE): a systematic review and meta-analysis of efficacy and safety

BACKGROUND

Oral immunotherapy is an emerging experimental treatment for peanut allergy, but its benefits and harms are unclear. We systematically reviewed the efficacy and safety of oral immunotherapy versus allergen avoidance or placebo (no oral immunotherapy) for peanut allergy.

METHODS

In the Peanut Allergen immunotherapy, Clarifying the Evidence (PACE) systematic review and meta-analysis, we searched MEDLINE, EMBASE, Cochrane Controlled Register of Trials, Latin American & Caribbean Health Sciences Literature, China National Knowledge Infrastructure, WHO's Clinical Trials Registry Platform, US Food and Drug Administration, and European Medicines Agency databases from inception to Dec 6, 2018, for randomised controlled trials comparing oral immunotherapy versus no oral immunotherapy for peanut allergy, without language restrictions. We screened studies, extracted data, and assessed risk of bias independently in duplicate. Main outcomes included anaphylaxis, allergic or adverse reactions, epinephrine use, and quality of life, meta-analysed by random effects. We assessed certainty (quality) of evidence by the GRADE approach. This study is registered with PROSPERO, number CRD42019117930.

RESULTS

12 trials (n=1041; median age across trials 8·7 years [IQR 5·9-11·2]) showed that oral immunotherapy versus no oral immunotherapy increased anaphylaxis risk (risk ratio [RR] 3·12 [95% CI 1·76-5·55], I²=0%, risk difference [RD] 15·1%, high-certainty), anaphylaxis frequency (incidence rate ratio [IRR] 2·72 [1·57-4·72], I²=0%, RD 12·2%, high-certainty), and epinephrine use (RR 2·21 [1·27-3·83], I²=0%, RD 4·5%, high-certainty) similarly during build-up and maintenance (p_interaction=0·92). Oral immunotherapy increased serious adverse events (RR 1·92 [1·00-3·66], I²=0%, RD 5·7%, moderate-certainty), and non-anaphylactic reactions (vomiting: RR 1·79 [95%CI 1·35-2·38], I²=0%, high-certainty; angioedema: 2·25 [1·13-4·47], I²=0%, high-certainty; upper tract respiratory reactions: 1·36 [1·02-1·81], I²=0%, moderate-certainty; lower tract respiratory reactions: 1·55 [0·96-2·50], I²=28%, moderate-certainty). Passing a supervised challenge, a surrogate for preventing out-of-clinic reactions, was more likely with oral immunotherapy (RR 12·42 [95% CI 6·82-22·61], I²=0%, RD 36·5%, high-certainty). Quality of life was not different between groups (combined parents and self report RR 1·21 [0·87-1·69], I²=0%, RD 0·03%, low-certainty). Findings were robust to IRR, trial sequential, subgroup, and sensitivity analyses.

INTERPRETATION

In patients with peanut allergy, high-certainty evidence shows that available peanut oral immunotherapy regimens considerably increase allergic and anaphylactic reactions over avoidance or placebo, despite effectively inducing desensitisation. Safer peanut allergy treatment approaches and rigorous randomised controlled trials that evaluate patient-important outcomes are needed.

FUNDING

None.

A network-based approach for identifying suitable biomarkers for oral immunotherapy of food allergy

BACKGROUND

Oral immunotherapy (OIT) is a promising therapeutic approach to treat food allergic patients. However, concerns with regards to safety and long-term efficacy of OIT remain. There is a need to identify biomarkers that predict, monitor and/or evaluate the effects of OIT. Here we present a method to select candidate biomarkers for efficacy and safety assessment of OIT using the computational approaches Bayesian networks (BN) and Topological Data Analysis (TDA).

RESULTS

Data were used from fructo-oligosaccharide diet-supported OIT experiments performed in 3 independent cow's milk allergy (CMA) and 2 independent peanut allergy (PNA) experiments in mice. Bioinformatical approaches were used to understand the data structure. The BN predicted the efficacy of OIT in the CMA with 86% and indicated a clear effect of scFOS/lcFOS on allergy parameters. For the PNA model, this BN (trained on CMA data) predicted an efficacy of OIT with 76% accuracy and shows similar effects of the allergen, treatment and diet as compared to the CMA model. The TDA identified clusters of biomarkers closely linked to biologically relevant clinical symptoms and also unrelated and redundant parameters within the network.

CONCLUSIONS

Here we provide a promising application of computational approaches to a) compare mechanistic features of two different food allergies during OIT b) determine the biological relevance of candidate biomarkers c) generate new hypotheses to explain why CMA has a different disease pattern than PNA and d) select relevant biomarkers for future studies.

First Real-World Safety Analysis of Preschool Peanut Oral Immunotherapy

BACKGROUND

In 2017, a clinical trial of 37 subjects demonstrated that preschool peanut oral immunotherapy (P-OIT) was safe, with predominantly mild symptoms reported and only 1 moderate reaction requiring epinephrine.

OBJECTIVES

We sought to examine whether these findings would be applicable in a real-world setting.

METHODS

As part of a Canada-wide quality improvement project, community and academic allergists administered P-OIT to preschool-age children who had (1) skin prick test wheal diameter greater than or equal to 3 mm or specific IgE level greater than or equal to 0.35 kU/L and history of reaction and/or positive baseline oral food challenge, or (2) no ingestion history and specific IgE level greater than or equal to 5 kU/L. Over 16 to 22 weeks, patients had biweekly clinic visits for updosing, and consumed the dose daily at home between visits. Target maintenance dose was 300 mg peanut protein. Symptoms were classified using a modified World Allergy Organization Subcutaneous Immunotherapy Reaction Grading System (1 mildest, 5 fatal).

RESULTS

Of 270 patients who started P-OIT in the period 2017 to 2018, 243 reached maintenance, and 27 dropped out (10.0%); 67.8% of patients experienced reactions during buildup: 36.3% grade 1, 31.1% grade 2, and 0.40% grade 4. Eleven patients (4.10%) received epinephrine (10 patients received 1 dose, 1 patient received epinephrine on 2 separate days), representing 2.23% of reactions (12 of 538) and 0.029% of doses (12 of 41,020).

CONCLUSIONS

We are the first group to describe preschool P-OIT in a real-world multicenter setting. The treatment appears to be safe for the vast majority of patients because symptoms were generally mild and very few reactions received epinephrine; however, life-threatening reactions in a minority of patients (0.4%) can still occur.

Reprograming immunity to food allergens

A novel immune-modulatory therapy utilizing targeted delivery of cytokines to draining lymph nodes effectively reprograms Th2 allergic responses towards a Th1 and tolerogenic profile, resulting in protection from peanut antigen-induced anaphylaxis.

B-FAHF-2 plus oral immunotherapy (OIT) is safer and more effective than OIT alone in a murine model of concurrent peanut/tree nut allergy

BACKGROUND

Concurrent sensitization to peanut (PN) and tree nuts (TN), the most dangerous food allergies, is common. Current oral immunotherapy (OIT) is not fully satisfactory.

OBJECTIVE

To determine whether the herbal formula B-FAHF-2 (BF2) ameliorates PN/TN OIT adverse reactions and enhances persistence of a tolerant state.

METHODS

Concurrently sensitized PN-, walnut- (WN) and cashew (CSH)-allergic mice received 1-day PN/WN/CSH rush OIT plus 3 weeks of maintenance dosing, with or without 3 weeks prior and 3 weeks BF2 co-treatment. Anaphylactic symptom scores, core body temperatures, plasma histamine levels, basophil numbers, antigen-specific IgE, cytokine levels, and IL-4, INF-γ and Foxp3 gene promoter DNA methylation status, and their correlation with final challenge symptom scores were determined.

RESULTS

BF2+OIT-treated mice experienced significantly fewer and less severe adverse reactions than OIT-only-treated mice (P<.01) during the 1-day rush OIT build-up dose phase. Both OIT-only and BF2+OIT mice showed significant desensitization (P<.01 and .001, respectively) at 1 week post-therapy challenge, being greater in BF2+OIT mice. All sham-treated and 91% of OIT-treated mice experienced anaphylaxis whereas only 21% of BF2+OIT-treated mice exhibited reactions during 5-6 weeks of dose escalation single PN and TN challenges. Greater and more persistent protection in BF2+OIT mice was associated with significantly lower plasma histamine and IgE levels, increased IFN-γ/IL-4 and IL-10/IL-4 ratios, DNA remethylation at the IL-4 promoter and demethylation at IFN-γ and Foxp3 promoters. Final challenge symptom scores were inversely correlated with IL-4 DNA methylation levels (P<.0002) and positively correlated with IFN-γ and Foxp3 gene promoter methylation levels (P<.0011) (P<.0165).

CONCLUSIONS AND CLINICAL RELEVANCE

Combined BF2/OIT therapy was safer and produced longer post-treatment protection and more tolerance-prone immunological and epigenetic modifications than OIT alone. BF2/OIT may provide an additional OIT option for patients with concurrent PN/TN and other food allergies.

Peanut-specific type 1 regulatory T cells induced in vitro from allergic subjects are functionally impaired

BACKGROUND

Peanut allergy (PA) is a life-threatening condition that lacks regulator-approved treatment. Regulatory T type 1 (T_R1) cells are potent suppressors of immune responses and can be induced in vivo upon repeated antigen exposure or in vitro by using tolerogenic dendritic cells. Whether oral immunotherapy (OIT) leads to antigen-specific T_R1 cell induction has not been established.

OBJECTIVES

We sought to determine whether peanut-specific T_R1 cells can be generated in vitro from peripheral blood of patients with PA at baseline or during OIT and whether they are functional compared with peanut-specific T_R1 cells induced from healthy control (HC) subjects.

METHODS

Tolerogenic dendritic cells were differentiated in the presence of IL-10 from PBMCs of patients with PA and HC subjects pulsed with the main peanut allergens of Arachis hypogaea, Ara h 1 and 2, and used as antigen-presenting cells for autologous CD4⁺ T cells (CD4⁺ T cells coincubated with tolerogenic dendritic cells pulsed with the main peanut allergens [pea-T10 cells]). Pea-T10 cells were characterized by the presence of CD49b⁺ lymphocyte-activation gene 3 (LAG3)⁺ T_R1 cells, antigen-specific proliferative responses, and cytokine production.

RESULTS

CD49b⁺LAG3⁺ T_R1 cells were induced in pea-T10 cells at comparable percentages from HC subjects and patients with PA. Despite their antigen specificity, pea-T10 cells of patients with PA with or without OIT, as compared with those of HC subjects, were not anergic and had high T_H2 cytokine production upon peanut-specific restimulation.

CONCLUSIONS

Peanut-specific T_R1 cells can be induced from HC subjects and patients with PA, but those from patients with PA are functionally defective independent of OIT. The unfavorable T_R1/T_H2 ratio is discussed as a possible cause of PA T_R1 cell impairment.

Data-driven programmatic approach to analysis of basophil activation tests

BACKGROUND

Conventional data analysis of flow cytometry-based basophil activation testing requires repetitive, labor-intensive analysis that hampers efforts to standardize testing for clinical applications. Using an open-source platform, we developed and implemented a programmatic approach to the analysis of the basophil activation test (BAT) by flow cytometry.

METHODS

Using the BÜHLMANN FlowCAST® assay, peripheral blood from peanut allergic patients undergoing oral immunotherapy was incubated with peanut allergens (Arah1, Arah2, Arah6, whole peanut extract) and stained with fluorescent antibodies to CCR3 and CD63 for the development of a data-driven programmatic analysis using Bioconductor and R. Basophil identification using clustering and classification was validated using manually gated comparisons in an experimental subset. Reproducibility of CD63 upregulation set on unstimulated or anti-FcERI stimulated basophils was compared.

RESULTS

BAT analysis of 294 experiments was successful in 91.5% using the above approach, with a total of 7,166 individual basophil activation tests from 269 experiments. We estimate this represents a net saving of 1340 min of labor by a skilled operator. Medium-based gating correlated to respective manual gating more closely than anti-FcERI based gating (R = 0.96 vs. R = 0.84, P < 0.001). Only 2% of the basophil activation results were significantly different from manual gating. Quality measures of the experiments and other measures of basophil activation were also provided by the analysis.

CONCLUSIONS

We present a novel data-driven flow cytometric platform for the analysis of clinical basophil activation testing, providing a high throughput objective approach to basophil activation analysis. © 2017 International Clinical Cytometry Society.

Wheat allergy: diagnosis and management

Triticum aestivum (bread wheat) is the most widely grown crop worldwide. In genetically predisposed individuals, wheat can cause specific immune responses. A food allergy to wheat is characterized by T helper type 2 activation which can result in immunoglobulin E (IgE) and non-IgE mediated reactions. IgE mediated reactions are immediate, are characterized by the presence of wheat-specific IgE antibodies, and can be life-threatening. Non-IgE mediated reactions are characterized by chronic eosinophilic and lymphocytic infiltration of the gastrointestinal tract. IgE mediated responses to wheat can be related to wheat ingestion (food allergy) or wheat inhalation (respiratory allergy). A food allergy to wheat is more common in children and can be associated with a severe reaction such as anaphylaxis and wheat-dependent, exercise-induced anaphylaxis. An inhalation induced IgE mediated wheat allergy can cause baker’s asthma or rhinitis, which are common occupational diseases in workers who have significant repetitive exposure to wheat flour, such as bakers. Non-IgE mediated food allergy reactions to wheat are mainly eosinophilic esophagitis (EoE) or eosinophilic gastritis (EG), which are both characterized by chronic eosinophilic inflammation. EG is a systemic disease, and is associated with severe inflammation that requires oral steroids to resolve. EoE is a less severe disease, which can lead to complications in feeding intolerance and fibrosis. In both EoE and EG, wheat allergy diagnosis is based on both an elimination diet preceded by a tissue biopsy obtained by esophagogastroduodenoscopy in order to show the effectiveness of the diet. Diagnosis of IgE mediated wheat allergy is based on the medical history, the detection of specific IgE to wheat, and oral food challenges. Currently, the main treatment of a wheat allergy is based on avoidance of wheat altogether. However, in the near future immunotherapy may represent a valid way to treat IgE mediated reactions to wheat.

The decrease in the IgG-binding capacity of intensively dry heated whey proteins is associated with intense Maillard reaction, structural changes of the proteins and formation of RAGE-ligands

Heat treatment is the most common way of milk processing, inducing structural changes as well as chemical modifications in milk proteins.

Allergen composition analysis and allergenicity assessment of Chinese peanut cultivars

Peanut (Arachis hypogaea) is among the eight major food allergens in the world. Several attempts have been made to decrease or eliminate the allergenicity of peanut. Systemic screening of thousands of peanut cultivars may identify peanut with low allergenicity. In this study, the allergen compositions of 53 Chinese peanut cultivars were characterized, and their allergenicity to sera IgE of Chinese patients and in a mouse model was assessed. Contents of total protein and allergens were quantified by SDS-PAGE and densitometry analysis on gel. Although the contents of allergens broadly varied among cultivars, they were related to one another. The IgE binding capacity of cultivars was tested by ELISA, and their allergenicity was further evaluated in a mouse model by oral sensitization. Results showed that the allergenicity of peanut was affected by allergen composition rather than a single allergen. Peanut cultivars with low allergenicity may contain more Ara h 3/4 (24 kDa), Ara h 2 and less Ara h 3/4 (43, 38, and 36 kDa), Ara h 6. Screening based on allergen composition would facilitate the identification of low-allergenic peanut.

Current opinion and review on peanut oral immunotherapy

In the last decade, peanut oral immunotherapy research has shown promise as an alternative treatment to avoidance in peanut-allergic patients. Research has not only focused on desensitization, but also on immunologic changes and sustained-tolerance. This article reviews the current literature and the historical background of oral immunotherapy as well as immune mechanisms in oral immunotherapy and other therapies being explored in food allergic individuals.

Chemical modification of peanut conglutin reduces IgE reactivity but not T cell reactivity in peanut-allergic patients

BACKGROUND

Specific immunotherapy for peanut allergy is associated with significant side-effects. Chemically modified allergens may provide a safer alternative.

OBJECTIVE

This study aimed to analyse the immunogenicity and allergenicity of modified peanut conglutin.

METHODS

Native peanut conglutin and two modifications thereof were generated (RA and RAGA). Conglutin-specific T cell lines from 11 peanut-allergic patients were analysed for proliferation and cytokine production. Sera from 14 patients were analysed for IgE/IgG1/IgG4 binding by immunoblot and ELISA. IgE reactivity was analysed by direct and indirect basophil activation test (BAT), in presence and absence of patient plasma or CD32-blocking antibodies.

RESULTS

T cell proliferation to RA was unchanged, and proliferation to RAGA was reduced compared to native conglutin. Cytokine profiles remained unchanged. IgE, IgG1 and IgG4 binding to RA and RAGA was significantly reduced. In the direct BAT, the relative potency of modified conglutin was decreased in 67% and increased/similar in 33% of the patients. In the indirect BAT, RA and RAGA were 10-100 times less potent than native conglutin. Addition of plasma to the indirect BAT increased the relative potency of modified conglutin in patients with high peanut-specific IgG levels. This was mediated via blocking of the response to native conglutin, most likely by soluble IgG, and not via CD32.

CONCLUSION AND CLINICAL RELEVANCE

Chemical modification of peanut conglutin by RA retains immunogenicity and reduces allergenicity and may be a promising approach for development of a curative treatment for peanut allergy. In a subgroup of patients, where the reactivity of native conglutin is already partially blocked by IgG, the effect of the modification of conglutin is less pronounced.

Time trends in Australian hospital anaphylaxis admissions in 1998-1999 to 2011-2012

BACKGROUND

Studies from the United Kingdom, the United States, and Australia have reported increased childhood food allergy and anaphylaxis prevalence in the 15 years after 1990.

OBJECTIVE

We sought to examine whether childhood food allergy/anaphylaxis prevalence has increased further since 2004-2005.

METHODS

We examined hospital anaphylaxis admission rates between 2005-2006 and 2011-2012 and compared findings with those from 1998-1999 to 2004-2005.

RESULTS

Overall population food-related anaphylaxis admission rates (per 10(5) population per year) increased from 5.6 in 2005-2006 to 8.2 in 2011-2012 (a 1.5-fold increase over 7 years). The highest rates occurred in children aged 0 to 4 years (21.7 in 2005-2006 and 30.3 in 2011-2012, a 1.4-fold increase), but the greatest proportionate increase occurred in those aged 5 to 14 years (5.8-12.1/10(5) population/y, respectively, a 2.1-fold increase) compared with those aged 15 to 29 years and 30 years or older (a 1.5- and 1.3-fold increase, respectively). Not only did absolute food-related anaphylaxis admissions increase, but the modeled year-on-year rate of increase in overall food-related anaphylaxis admissions also increased over time from an additional 0.35 per 10(5) population/y in 1998-1999 (all ages) to 0.49 in 2004-2005 and 0.63 in 2011-2012 (P < .001).

CONCLUSIONS

Food-related anaphylaxis has increased further in all age groups since 2004-2005. Although the major burden falls on those aged 0 to 4 years, there is preliminary evidence for a recent acceleration in incidence rates in those aged 5 to 14 years. This contrasts with the previous decade in which the greatest proportionate increase was in those aged 0 to 4 years. These findings suggest a possible increasing burden of disease among adolescents and adults who carry the highest risk for fatal anaphylaxis.

Current developments for improving efficacy of allergy vaccines

Allergic diseases are prevalent worldwide. Allergen immunotherapy (AIT) is a current treatment for allergy, leading to modification of the natural course of disease. Mechanisms of efficacy include Treg through release of IL-10 and TGF-β and specific IgG4 blocking antibodies. Subcutaneous and sublingual routes are popular, but uptake is limited by inconvenience and safety concerns. Inclusion criteria limit application to a small proportion of allergic patients. New forms of immunotherapy are being investigated for more efficacious, convenient and safer options with promising advances in recent years. The rationale of reducing vaccine allergenicity to increase safety while improving immunogenicity led to investigation of T-cell epitope-based peptides and recombinant allergen derivatives. Additionally, different routes of administration and adjuvants and adjunct therapies are being explored. This review discusses the current status of AIT and recent advances to improve clinical efficacy, safety and long-term immune tolerance.

A Web site-based reporting system for monitoring home treatment during oral immunotherapy for food allergy

BACKGROUND

Reactions during the home treatment phase of oral immunotherapy (OIT) are not uncommon. An ongoing accurate reporting of home treatment outcomes is crucial for the safety and success of OIT. Previous reports have shown that as few as 20% of patients are truly compliant with paper-based diaries.

OBJECTIVE

To develop a Web site-based electronic reporting system (web-RS) for monitoring home treatment during OIT for food allergy.

METHODS

A web-RS was developed and incorporated a thorough questionnaire querying for pertinent data including the dose(s) consumed, occurrence and details of adverse reactions, treatment(s), and relevant potential exacerbating factors. All patients enrolled in milk, peanut, or egg OIT programs for at least 4 weeks from November 2012 through January 2014 were introduced to web-RS (n = 157). Successful reporting through web-RS was defined by consecutive reporting during the first home treatment phase (24 days) after its introduction. Comparisons were made with a previous group of OIT-treated patients (n = 100) who reported by E-mail.

RESULTS

Successful reporting was achieved by 142 of 157 patients (90.44%) in contrast to a 75% success rate with E-mail (P = .0009). The odds for successful reporting using web-RS were 3.1 (95% confidence interval 1.6-6.3) times higher compared with using E-mail. Mild reactions were reported more frequently with web-RS (P = .0032). Patient reports were constantly available in real time for medical staff review. No complaints regarding web-RS feasibility were reported. One risk factor for failure to use web-RS was a patient's prior successful OIT experience without using web-RS (P = .012).

CONCLUSION

A web-RS can be a powerful tool for improving OIT safety by achieving a high level of patient cooperation in reporting home treatment results.

Treatment of allergic reactions and quality of life among caregivers of food-allergic children

BACKGROUND

Caregivers of food-allergic individuals (FAIs) have decreased quality of life (QoL). The effects of epinephrine administration on QoL are poorly understood.

OBJECTIVE

To investigate the relation between QoL and epinephrine use.

METHODS

A de-identified 50-question online survey was administered to caregivers of FAIs across the United States through Web site, email, and social media networks of 2 national food allergy advocacy groups. QoL was assessed using the Food Allergy Quality of Life-Parental Burden questionnaire. The effect of prior epinephrine administration on QoL was analyzed using linear regression.

RESULTS

Of 3,541 respondents, 35.6% reported their FAIs received epinephrine. Mean Food Allergy Quality of Life-Parental Burden scores were higher (worse QoL) in those reporting FAIs receiving epinephrine (3.07 vs 2.84, P < .001), anaphylaxis (3.01 vs 2.75, P < .001), multiple food allergies (3.16 vs 2.67, P < .001), and multiple food allergies and epinephrine use (3.24 vs 2.57, P < .001) vs those who did not. In a regression model, reported epinephrine use; anaphylaxis; multiple FAIs; multiple food allergies; and egg or milk, wheat or soy, or seafood allergy (vs peanut or tree nut allergy) were significantly associated with an increased (worse) QoL score. Caregiver college education and increasing FAI age were associated with a decreased QoL score (improved QoL). An interaction was noted between reported epinephrine use and anaphylaxis and was associated with a decreased QoL score.

CONCLUSION

The effect of epinephrine use on caregiver QoL is conditional and depends on reaction severity. Having multiple FAIs and FAIs with multiple food allergies was associated with worsening QoL. Further studies are needed to better understand the effects of treating an allergic reaction on caregiver QoL.

Allergist-reported trends in the practice of food allergen oral immunotherapy

Food allergen oral immunotherapy (OIT) is an experimental, immune-modifying therapy that may induce clinical desensitization in some patients. OIT is still in early phase clinical research, but some providers may offer OIT as a clinical service. To understand the current practices of allergists who perform OIT, an online survey was sent by e-mail to members of the American Academy of Allergy Asthma & Immunology. Among 442 respondents, 61 reported participating in using OIT (13.8%), including 28 in nonacademic settings. Informed consent for OIT was obtained by 91.3%, institutional review board approval by 47.7% and Investigational New Drug approval by 38.1%. Compared with nonacademic participants, more academic participants used peanut OIT, obtained institutional review board and Investigational New Drug (P < .0001 respectively), and challenged patients before entry (P = .008). More nonacademic providers billed the patient or insurance for reimbursement (P < .0001). Low reported regard for the importance for US Food and Drug Administration approval or a standardized product (increased odds), and a high regard for better safety data (decreased odds) were associated with considering offering OIT as a service. Significant differences exist with OITs that occur in academic versus nonacademic settings. Further assessment is needed regarding the different motivations and practice styles among providers who offer OIT and those who are considering doing so.

Immunogenicity of peanut proteins containing poly(anhydride) nanoparticles

In the last decade, peanut allergy has increased substantially. Significant differences in the prevalence among different countries are attributed to the type of thermal processing. In spite of the high prevalence and the severe reaction induced by peanuts, there is no immunotherapy available. The aim of this work was to evaluate the potential application of poly(anhydride) nanoparticles (NPs) as immunoadjuvants for peanut oral immunotherapy. NPs loaded with raw or roasted peanut proteins were prepared by a solvent displacement method and dried by either lyophilization or spray-drying. After physicochemical characterization, their adjuvant capacity was evaluated after oral immunization of C57BL/6 mice. All nanoparticle formulations induced a balanced T(H)1 and T(H)2 antibody response, accompanied by low specific IgE induction. In addition, oral immunization with spray-dried NPs loaded with peanut proteins was associated with a significant decrease in splenic T(H)2 cytokines (interleukin 4 [IL-4], IL-5, and IL-6) and enhancement of both T(H)1 (gamma interferon [IFN-γ]) and regulatory (IL-10) cytokines. In conclusion, oral immunization with poly(anhydride) NPs, particularly spray-dried formulations, led to a pro-T(H)1 immune response.

Oral Immunotherapy for Treatment of Immunoglobulin E-Mediated Food Allergy: The Transition to Clinical Practice

Today, there is neither an effective nor an active treatment for food allergy. Allergy immunotherapy has been proposed as an attractive strategy to actively treat food allergy. Oral immunotherapy (OIT), also known as oral desensitization, is a method of inducing the body's immune system to tolerate a food that causes an allergic overreaction. It has been studied for the use in treatment of immunoglobulin E-mediated food allergy to the most common foods, including milk, egg, and peanut. OIT has been able to desensitize subjects to varying degrees. However, many questions remain unanswered, including efficient formulation, optimal dosing, and induction protocol to achieve full tolerance, transition of OIT to clinical practice, and maximal safety profile. This review focuses on the use of OIT as a new and active treatment for food allergy. The possibility of transition of OIT to clinical practice represents, in this field, the next pivotal step with the goal of improving the quality of life of patients with food allergy and their families.

Strategies to Mitigate Peanut Allergy: Production, Processing, Utilization, and Immunotherapy Considerations

Peanut (Arachis hypogaea L.) is an important crop grown worldwide for food and edible oil. The surge of peanut allergy in the past 25 years has profoundly impacted both affected individuals and the peanut and related food industries. In response, several strategies to mitigate peanut allergy have emerged to reduce/eliminate the allergenicity of peanuts or to better treat peanut-allergic individuals. In this review, we give an overview of peanut allergy, with a focus on peanut proteins, including the impact of thermal processing on peanut protein structure and detection in food matrices. We discuss several strategies currently being investigated to mitigate peanut allergy, including genetic engineering, novel processing strategies, and immunotherapy in terms of mechanisms, recent research, and limitations. All strategies are discussed with considerations for both peanut-allergic individuals and the numerous industries/government agencies involved throughout peanut production and utilization.

Ara h 1 CD4+ T cell epitope-based peptides: candidates for a peanut allergy therapeutic

Background

Peanut allergy is a life-threatening condition; there is currently no cure. While whole allergen extracts are used for specific immunotherapy for many allergies, they can cause severe reactions and even fatalities in peanut allergy.

Objective

To identify short, HLA-degenerate CD4⁺ T cell epitope-based peptides of the major peanut allergen Ara h 1 that target allergen-specific T cells without causing IgE-mediated inflammatory cell activation, as candidates for safe peanut-specific immunotherapy.

Methods

Ara h 1-specific CD4⁺ T cell lines (TCL) were generated from peripheral blood mononuclear cells (PBMC) of peanut-allergic subjects using CFSE-based methodology. T cell epitopes were identified using CFSE and thymidine-based proliferation assays. Epitope HLA-restriction was investigated using blocking antibodies, HLA-genotyping and epitope prediction algorithms. Functional peanut-specific IgE reactivity to peptides was assessed by basophil activation assay.

Results

A total of 145 Ara h 1-specific TCL were generated from 18 HLA-diverse peanut-allergic subjects. The TCL recognized 20-mer peptides throughout Ara h 1. Nine 20-mers containing the most frequently recognized epitopes were selected and their recognition confirmed in 18 additional peanut-allergic subjects. Ten core epitopes were mapped within these 20-mers. These were HLA-DQ and/or HLA–DR restricted, with each presented on at least two different HLA-molecules. Seven short (≤ 20 aa) non-basophil-reactive peptides encompassing all core epitopes were designed and validated in peanut-allergic donor PBMC T cell assays.

Conclusions and Clinical Relevance

Short CD4⁺ T cell epitope-based Ara h 1 peptides were identified as novel candidates for a safe, T cell targeted peanut-specific immunotherapy for HLA-diverse populations.

IgE-mediated food allergy in children

Food allergy is a serious health issue affecting roughly 4% of children, with a substantial effect on quality of life. Prognosis is good for the most frequent allergens with almost all children outgrowing their allergy. However, the long-term implications for disease burden are substantial for children with persistent allergies (eg, peanuts, tree nuts, fish, and shellfish) and for those with high concentrations of milk, egg, and wheat IgE. Antigen avoidance has been the time-honoured approach both for prevention and treatment. However, findings from studies done in the past 5 years show that early contact with food can induce tolerance and desensitisation to foods. We review the epidemiology, natural history, and management of food allergy, and discuss the areas of controversy and future directions in research and clinical practice.

Food allergy diagnosis and therapy: where are we now?

Food allergy is a growing worldwide epidemic that adversely effects up to 10% of the population. Causes and risk factors remain unclear and diagnostic methods are imprecise. There is currently no accepted treatment for food allergy. Therefore, there is an imminent need for greater understanding of food allergies, revised diagnostics and development of safe, effective therapies. Oral immunotherapy provides a particularly promising avenue, but is still highly experimental and not ready for clinical use.

Knowledge and attitudes of primary care physicians regarding food allergy and anaphylaxis in Turkey

BACKGROUND

Food allergy, which becomes an important public health problem, can lead to important morbidity and mortality. Patients with food allergies are more likely to first present to their primary care physicians. We aimed to determine the knowledge of primary care physicians with regard to management of food allergies and anaphylaxis.

METHODS

Primary care physicians were surveyed via a questionnaire aimed to document their knowledge and attitudes about food allergy and anaphylaxis management.

RESULTS

A total of 297 participants completed questionnaires, 55.6% of which were female. Participating physicians had a mean of 17.0 ± 6.1 years of experience. Participants answered 47.2% of knowledge-based items correctly. Overall, participants fared poorly with regard to their knowledge on the treatment of food allergies and anaphylaxis. For example while 60.7% knew that a child can die from the milk allergy reaction, only 37.5% were aware that a child with IgE mediated milk allergies cannot eat yoghourts/cheese with milk. Besides, 53.1% of them chose epinephrine as their first treatment of choice in case of anaphylaxis, yet only 16.6% gave the correct answer about its dosage. Nearly a third of participants (36.7%) felt they were knowledgeable enough regarding the management of patients with food allergies, while 98.2% extended their request for future periodic educational meetings on allergic disorders.

CONCLUSION

Knowledge of food allergy and anaphylaxis among primary care physicians was unsatisfactory. Provision or periodic educational programmes should be aimed at improving the standard of practice as acknowledged by the participants.

In silico prediction of Ara h 2 T cell epitopes in peanut-allergic children

BACKGROUND

Despite the frequency and severity of peanut allergy, the only approved treatment is strict avoidance. Different types of immunotherapy with crude peanut extract are not universally effective and have been associated with relatively high adverse reaction rates.

OBJECTIVE

We sought to determine whether in silico predictive algorithms were useful in identifying candidate peptides for an Ara h 2 peptide-based vaccine using peanut-allergic patients' peripheral blood mononuclear cells (PBMCs) in vitro. A human leucocyte antigen (HLA) distribution analysis was also performed.

METHODS

Major histocompatibility complex (MHC)-class II-binding peptides were predicted using NetMHCIIpan-2.0 and NetMHCII-2.2 algorithms. PBMCs from 80 peanut-allergic patients were stimulated with overlapping 20-mer Ara h 2 peptides. Cell supernatant cytokine profiles were evaluated by multiplex assays. HLA-DRB1* and HLA-DQB1* typing were performed.

RESULTS

Four regions of overlapping sequences induced PBMC proliferation and predominant Th2 cytokine production. HLA genotyping showed 30 different DRB1* allele specificities and eight DQ serological specificities. The in silico analysis revealed similar relevant regions and predicted identical or similar core 9-mer epitopes to those identified in vitro. If relevant peptides, as determined by either in vitro or in silico analysis (15 peptides and 9 core epitopes respectively), were used in a peptide-based vaccine, they would cover virtually all subjects in the cohort studied.

CONCLUSIONS AND CLINICAL RELEVANCE

Four dominant regions in Ara h 2 have been identified, containing sequences that could serve as potential candidates for peptide-based immunotherapy. MHC-class II-based T cell epitope prediction algorithms for HLA-DR and -DQ loci accurately predicted Ara h 2 T cell epitopes in peanut-allergic subjects, suggesting their potential utility in a peptide-based vaccine design for food allergy.

Oral immunotherapy for food allergy: clinical and preclinical studies

Food allergies affect approximately 5% of the U.S. population and have increased in the last decade. In recent years, oral immunotherapy (OIT) has been tested in clinical trials for peanut, milk, and egg allergies in young children. OIT appears to be fairly well tolerated by most subjects and leads to desensitization with a greatly increased threshold of allergen required to induce reactions. Further approaches being investigated in preclinical studies in mouse models indicate the potential for using adjuvants, such as TLR9 agonists in combination with OIT; peptide OIT; and non-allergen specific applications such as herbal formulations. Further questions about OIT remain, including the optimal dosing and length of treatment; whether tolerance can be developed; and the exact cellular mechanisms resulting in protection following OIT. With many clinical trials underway across the United States and other countries, and a growing pipeline of preclinical research with translational potential, there is great hope for a widely applicable food allergy treatment.

A phase 1 study of heat/phenol-killed, E. coli-encapsulated, recombinant modified peanut proteins Ara h 1, Ara h 2, and Ara h 3 (EMP-123) for the treatment of peanut allergy

BACKGROUND

Immunotherapy for peanut allergy may be limited by the risk of adverse reactions.

OBJECTIVE

To investigate the safety and immunologic effects of a vaccine containing modified peanut proteins.

METHODS

This was a phase 1 trial of EMP-123, a rectally administered suspension of recombinant Ara h 1, Ara h 2, and Ara h 3, modified by amino acid substitutions at major IgE-binding epitopes, encapsulated in heat/phenol-killed E. coli. Five healthy adults were treated with 4 weekly escalating doses after which 10 peanut-allergic adults received weekly dose escalations over 10 weeks from 10 mcg to 3063 mcg, followed by three biweekly doses of 3063 mcg.

RESULTS

There were no significant adverse effects in the healthy volunteers. Of the 10 peanut-allergic subjects [4 with intermittent asthma, median peanut IgE 33.3 kUA /l (7.2-120.2), and median peanut skin prick test wheal 11.3 mm (6.5-18)]; four experienced no symptoms; one had mild rectal symptoms; and the remaining five experienced adverse reactions preventing completion of dosing. Two were categorized as mild, but the remaining three were more severe, including one moderate reaction and two anaphylactic reactions. Baseline peanut IgE was significantly higher in the five reactive subjects (median 82.4 vs 17.2 kUA /l, P = 0.032), as was baseline anti-Ara h 2 IgE (43.3 versus 8.3, P = 0.036). Peanut skin test titration and basophil activation (at a single dilution) were significantly reduced after treatment, but no significant changes were detected for total IgE, peanut IgE, or peanut IgG4.

CONCLUSIONS

Rectal administration of EMP-123 resulted in frequent adverse reactions, including severe allergic reactions in 20%.

Practical approach to nutrition and dietary intervention in pediatric food allergy

Although the need for nutritional and dietary intervention is a common thread in food allergy management, the type of food allergic disorder and the identified food allergen will influence the approach to dietary intervention. A comprehensive nutrition assessment with appropriate intervention is warranted in all children with food allergies to meet nutrient needs and optimize growth. However, dietary elimination in food allergy may also have undesirable consequences. Frequently, an elimination diet is absolutely necessary to prevent potentially life-threatening food allergic reactions. Allergen elimination can also ease chronic symptoms, such as atopic dermatitis, when a food is proven to trigger symptoms. However, removing a food with proven sensitivity to treat chronic symptoms may increase the risk of an acute reaction upon reintroduction or accidental ingestion after long-term avoidance, so it is not without risk. Additionally, it is not recommended to avoid foods in an attempt to control chronic symptoms such as AD and EoE when allergy to the specific food has not been demonstrated. Ultimately, allergen elimination goals are to prevent acute and chronic food allergic reactions in the least restrictive, but also the safest environment to supply a balanced diet that promotes health and growth and development in children.

New directions in immunotherapy

Allergen immunotherapy (AIT) is effective in reducing the clinical symptoms associated with allergic rhinitis, asthma and venom-induced anaphylaxis. Subcutaneous (SCIT) and sublingual immunotherapy (SLIT) with unmodified allergen extracts are the most widely prescribed AIT regimens. The efficacy of these 2 routes appears comparable, but the safety profile with SLIT is more favorable allowing for home administration and requiring less patient time. However, both require that the treatment is taken regularly over several years, e.g., monthly in a supervised medical setting with SCIT and daily at home with SLIT. Despite the difference in treatment settings, poor adherence has been reported with both routes. Emerging evidence suggests that AIT may be effective in other allergic conditions such as atopic dermatitis, venom sting-induced large local reactions, and food allergy. Research with oral immunotherapy (OIT) for food allergies suggest that many patients can be desensitized during treatment, but questions remain about whether this can produce long term tolerance. Further studies are needed to identify appropriate patients and treatment regimens with these conditions. Efforts to develop safer and more effective AIT for inhalant allergies have led to investigations with modified allergens and alternate routes. Intralymphatic (ILIT) has been shown to produce long-lasting clinical benefits after three injections comparable to a 3-year course of SCIT. Epicutaneous (EPIT) has demonstrated promising results for food and inhalant allergies. Vaccine modifications, such as T cell epitopes or the use of viral-like particles as an adjuvant, have been shown to provide sustained clinical benefits after a relatively short course of treatment compared to the currently available AIT treatments, SLIT and SCIT. These newer approaches may increase the utilization and adherence to AIT because the multi-year treatment requirement of currently available AIT is a likely deterrent for initiating and adhering to treatment.

Latitude, sunlight, vitamin D, and childhood food allergy/anaphylaxis

Vitamin D is widely known for its role in bone metabolism, but this sterol hormone also has important immunomodulatory properties. Vitamin D is produced by the conversion of D3 in the skin following UVB exposure, or after ingestion of D2 or D3. At the extremes of latitude, there is insufficient UVB intensity in the autumn and winter months for adequate synthesis of vitamin D to occur. Growing evidence implicates vitamin D deficiency in early life in the pathogenesis of nonskeletal disorders (e. g., type 1 diabetes and multiple sclerosis) and, more recently, atopic disorders. Several studies have reported higher rates of food allergy/anaphylaxis or proxy measures at higher absolute latitudes. Although causality remains to be determined, these studies suggest a possible role for sunlight and/or vitamin D in the pathogenesis of food allergy/anaphylaxis.

Type B CpG oligodeoxynucleotides induce Th1 responses to peanut antigens: modulation of sensitization and utility in a truncated immunotherapy regimen in mice

SCOPE

Peanut allergy stems from a Th2-biased immune response to peanut allergens leading to IgE production and allergic reactions upon ingestion.

METHODS AND RESULTS

A model of peanut allergy in C3H/HeJ mice was used to assess whether type A, B, or C CpG oligodeoxynucleotide (ODN) molecules would be effective in: (i) a prophylactic approach to prevent peanut allergy when administered simultaneously with a Th2-skewing adjuvant, and (ii) a therapeutic model to allow for shortened immunotherapy. Type B ODNs were extremely effective in inhibiting anaphylaxis in the sensitization protocol as evidenced by differences in symptom scores, body temperature, and mouse mast cell protease 1 release compared to sham treatment. In the therapeutic model, co-administration of type B ODN plus peanut proteins was highly effective in reducing anaphylactic reactions in mice with established peanut allergy. The therapeutic effect was accompanied by an increase in IFN-γ and peanut-IgG2a, without a significant decrease in peanut IgE or IL-4 responses.

CONCLUSION

CpG ODNs, especially type B, were highly effective in inducing Th1 responses in mice undergoing induction of peanut allergy, as well as in mice undergoing therapy for established peanut allergy. Interestingly, the IgE response was not significantly altered, suggesting that IgG antibodies may be enough to prevent peanut-induced anaphylaxis.

Peanut oral immunotherapy: is it ready for clinical practice?

The prevalence of peanut allergy in the United States and other Westernized countries has tripled in the past 15 years, now affecting more than 1% of the population. Strict peanut avoidance is the current standard of care. In the past decade, a number of small, largely uncontrolled clinical trials have suggested that oral immunotherapy (OIT) can effectively desensitize most children with peanut allergy. Some in the allergy community now feel that OIT is ready for clinical practice. In this review, the evidence base in the medical literature is examined. Although peanut OIT shows promise, the evidence currently available on its effectiveness, risk benefit, and potential long-term consequences is insufficient to support its use in clinical practice. Appropriately designed, prospective clinical trials are urgently needed to determine whether OIT is a safe, effective form of therapy for food allergy.

Community opinions regarding oral immunotherapy for food allergies

BACKGROUND

Food oral immunotherapy (OIT) is a promising but still investigational new therapy for food allergy.

OBJECTIVE

We sought to investigate beliefs and opinions among OIT participants and nonparticipants to better understand community awareness of this therapy.

METHODS

A 30-question on-line survey was administered to members, website visitors, and social media followers of the Kids with Food Allergy Foundation. Questions inquired about general knowledge and attitudes about OIT, its reported safety and efficacy, complications, insurance coverage, and its Food and Drug Administration (FDA) approval status.

RESULTS

Among 1,274 survey respondents, 15.9% had discussed OIT as a treatment option with their allergy provider. Five percent (n = 64) of respondents reported that their child was currently participating in OIT, including 73.4% (n = 47) in a private practice setting. Participants reported varying degrees of being informed about OIT safety (85%), efficacy (46.4% told unrestricted ingestion), risks (relapse 53.4%, eosinophilic esophagitis 3.5%, oral allergy syndrome 10.7%, and failure 56.9%). Significantly fewer participants than nonparticipants agreed that OIT's present safety, efficacy, risks, and approval status would dissuade participation. Significantly fewer participants agreed that OIT should not be offered outside the research setting without definitive proof of both its safety and efficacy.

CONCLUSION

In this exploratory study, differences in beliefs and opinions existed between OIT participants and nonparticipants. Among participants, there were also significant differences in beliefs among academic versus nonacademic participants. Accurate and complete information about OIT safety, efficacy, risks, and approval status was not universally conveyed.

Blockade of peanut allergy with a novel Ara h 2-Fcγ fusion protein in mice

BACKGROUND

Conventional immunotherapy for peanut allergy using crude peanut extracts is not recommended because of the unacceptably high risk of anaphylaxis. Allergen-specific immunotherapy is not currently undertaken for peanut allergy.

OBJECTIVES

The objective of this study was to develop a novel peanut-human fusion protein to block peanut-induced anaphylaxis.

METHODS

We genetically designed and expressed a novel plant-human fusion protein composed of the major peanut allergen Ara h 2 and human IgG Fcγ1. We tested the Ara h 2-Fcγ fusion protein (AHG2)'s function in purified human basophils. Transgenic mice expressing human FcεRIα and a murine peanut allergy model were used.

RESULTS

AHG2 inhibited histamine release induced by whole peanut extract (WPE) from basophils of patients with peanut allergy, whereas the fusion protein itself did not induce mediator release. AHG2 inhibited the WPE-induced, peanut-specific, IgE-mediated passive cutaneous anaphylaxis in hFcεRIα transgenic mice. AHG2 also significantly inhibited acute anaphylactic reactivity, including the prototypical decrease in body temperature in WPE-sensitized mice challenged with crude peanut extract. Histologic evaluation of the airways showed that AHG2 decreased peanut-induced inflammation, whereas the fusion protein itself did not induce airway inflammation in peanut-sensitized mice. AHG2 did not exert an inhibitory effect in mice lacking FcγRII.

CONCLUSION

AHG2 inhibited peanut-specific IgE-mediated allergic reactions in vitro and in vivo. Linking specific peanut allergen to Fcγ can provide a new approach for the allergen immunotherapy of peanut allergy.

Dietary baked egg accelerates resolution of egg allergy in children

BACKGROUND

Baked egg is tolerated by a majority of egg-allergic children.

OBJECTIVE

To characterize immunologic changes associated with ingestion of baked egg and evaluate the role that baked egg diets play in the development of tolerance to regular egg.

METHODS

Egg-allergic subjects who tolerated baked egg challenge incorporated baked egg into their diet. Immunologic parameters were measured at follow-up visits. A comparison group strictly avoiding egg was used to evaluate the natural history of the development of tolerance.

RESULTS

Of the 79 subjects in the intent-to-treat group followed for a median of 37.8 months, 89% now tolerate baked egg and 53% now tolerate regular egg. Of 23 initially baked egg-reactive subjects, 14 (61%) subsequently tolerated baked egg and 6 (26%) now tolerate regular egg. Within the initially baked egg-reactive group, subjects with persistent reactivity to baked egg had higher median baseline egg white (EW)-specific IgE levels (13.5 kU(A)/L) than those who subsequently tolerated baked egg (4.4 kU(A)/L; P= .04) and regular egg (3.1 kU(A)/L; P= .05). In subjects ingesting baked egg, EW-induced skin prick test wheal diameter and EW-, ovalbumin-, and ovomucoid-specific IgE levels decreased significantly, while ovalbumin- and ovomucoid-specific IgG(4) levels increased significantly. Subjects in the per-protocol group were 14.6 times more likely than subjects in the comparison group (P< .0001) to develop regular egg tolerance, and they developed tolerance earlier (median 50.0 vs 78.7 months; P< .0001).

CONCLUSION

Initiation of a baked egg diet accelerates the development of regular egg tolerance compared with strict avoidance. Higher serum EW-specific IgE level is associated with persistent baked and regular egg reactivity, while initial baked egg reactivity is not.

Elevated antigen-driven IL-9 responses are prominent in peanut allergic humans

Food allergies, and peanut allergy in particular, are leading causes of anaphylactic fatalities worldwide. The immune mechanisms that underlie food allergy remain ill-defined and controversial, in part because studies in humans typically focus on analysis of a limited number of prototypical Th1/Th2 cytokines. Here we determine the kinetics and prevalence of a broad panel of peanut-driven cytokine and chemokine responses in humans with current peanut allergy vs those with stable, naturally occurring clinical tolerance to peanut. Our primary focus is identification of novel indicators of immune dysregulation. Antigen-specific cytokine mRNA and protein responses were elicited in primary culture via peanut or irrelevant antigen (Leishmania extract, milk antigens) mediated stimulation of fresh peripheral blood cells from 40 individuals. Peanut extract exposure in vitro induced a broad panel of responses associated with Th2/Th9-like, Th1-like and Th17-like immunity. Peanut-dependent Type 2 cytokine responses were frequently found in both peanut allergic individuals and those who exhibit clinical tolerance to peanut ingestion. Among Th2/Th9-associated cytokines, IL-9 responses discriminated between allergic and clinically tolerant populations better than did commonly used IL-4, IL-5 or IL-13 responses. Comparison with responses evoked by unrelated control antigen-mediated stimulation showed that these differences are antigen-dependent and allergen-specific. Conversely, the intensity of IL-12, IL-17, IL-23 and IFN-γ production was indistinguishable in peanut allergic and peanut tolerant populations. In summary, the ability to generate and maintain cytokine responses to peanut is not inherently distinct between allergic and peanut tolerant humans. Quantitative differences in the intensity of cytokine production better reflects clinical phenotype, with optimally useful indicators being IL-9, IL-5, IL-13 and IL-4. Equivalent, and minimal, Ag-dependent pro-inflammatory cytokine levels in both healthy and peanut allergic volunteers argues against a key role for such cytokines in maintenance of clinical tolerance to food antigens in humans.

Effect of oral immunotherapy to peanut on food-specific quality of life

BACKGROUND

Peanut allergy is an increasingly common problem for which the only available treatment is avoidance. Oral immunotherapy has shown promise for increasing tolerance of peanut in allergic children. Food allergy has an effect on the quality of life of children and adolescents.

OBJECTIVE

To measure the effect of oral immunotherapy to peanut on food-specific quality of life in children and adolescents.

METHODS

One hundred patients (5-18 years of age) were enrolled in an open trial of peanut oral immunotherapy. Parents of children 5 to 12 years old, children 8 to 12 years old, and teenagers completed validated, age-specific, food-related quality-of-life surveys before and after peanut oral immunotherapy.

RESULTS

Ninety patients (76 children 5-12 years old and 14 adolescents 13-18 years old) achieved the maintenance daily dose of 450 mg of peanut protein. A significant improvement in quality of life was found in all survey domains (allergen avoidance, dietary restriction, risk of accidental exposure, emotional impact, food-related anxiety, and social and dietary limitations) with the exception of the emotional impact domain on the adolescents' survey. Quality of life significantly improved (P < .02) on all 30 questions when parents assessed their children 5 to 12 years old. When children (8-12 years old) and teens assessed themselves, quality of life improved (P < .05) on 22 of 24 questions and 12 of 18 questions, respectively.

CONCLUSION

Peanut oral immunotherapy significantly improves food-specific quality of life.