AR101 Oral Immunotherapy for Peanut Allergy

Impact du confinement sur le suivi des immunothérapies orales alimentaires : étude multicentrique dans 3 centres d’Île-de-France

But de l’étude

Plusieurs études ont confirmé l’impact du confinement sur la population, entraînant une rupture de soins, des effets somatiques et psychologiques. Notre étude s’intéresse aux effets indésirables et aux problèmes d’observance au cours d’immunothérapie orale (ITO) alimentaires pendant le confinement.

Patients et méthodes

Au total, 132 patients, majoritairement des enfants (95 %), avec un antécédent atopique (60 %) suivis pour une ITO ont été inclus dans 3 centres d’allergologie en Île-de-France, pendant le confinement lié à la pandémie SARS-Cov-2 du 16/03 au 11/05/20. Les aliments des ITO étaient principalement l’arachide (38 %), le lait de vache (24 %), la noisette (14 %), l’œuf (9 %), la noix de cajou et la pistache (8 %).

Résultats

Des effets indésirables ont été retrouvés chez 13 patients soit 10 % des cas. Ces réactions étaient principalement de grade 1 et 2 selon la classification de Ring et Messmer. Trois patients ont présenté des réactions de grade 3 et six patients ont utilisé l’adrénaline au domicile. L’observance était correcte dans 81 % des cas sans aucun oubli. Trois patients ont augmenté leur dose quotidienne sans avis médical. Nous n’avons pas retrouvé de différence significative dans l’analyse en sous-groupe comparant des enfants appariés en âge suivis en ITO en 2019 et en 2020 sur la même période dans le même hôpital.

Conclusion

Il n’y a pas eu d’augmentation des effets indésirables au cours d’ITO pendant la période du confinement. L’éducation thérapeutique au cours de l’ITO est primordiale et participe à réduire la survenue d’effets indésirables.

Epicutaneous immunotherapy for treatment of peanut allergy: Follow-up from the Consortium for Food Allergy Research

BACKGROUND

Consortium for Food Allergy Research investigators previously reported 52-week outcomes from a randomized controlled trial of peanut epicutaneous immunotherapy, observing modest and statistically significant induction of desensitization, highest in children ages 4 to 11 years.

OBJECTIVE

We sought to evaluate changes in efficacy, safety, and mechanistic parameters following extended open-label peanut epicutaneous immunotherapy.

METHODS

Peanut-allergic participants (4-25 years) received 52 weeks of placebo (PLB), Viaskin Peanut 100 μg (VP100) or 250 μg (VP250), and then crossed over to VP250 for PLB (PLB-VP250) and VP100 (VP100-VP250) participants and continued treatment for VP250 participants (total = 130 weeks of active epicutaneous immunotherapy). Efficacy was assessed by double-blind, placebo-controlled food challenge (5044 mg peanut protein), and adherence, safety, and mechanistic parameters were evaluated.

RESULTS

At week 130, desensitization success was achieved in 1 of 20 (5%) PLB-VP250, 5 of 24 (20.8%) VP100-VP250, and 9 of 25 (36%) VP250 participants, with median successfully consumed dose change from baseline of 11.5 mg, 141.5 mg, and 400 mg, respectively. Median age (years) for week 130 desensitization success was 6.2 years (interquartile range, 5.2-9.1) versus 9.4 years (interquartile range, 7.6-12.8) for failures (P < .001). Adherence was 96%. Adverse reactions were predominantly local patch-site reactions. Significant increases in peanut- and Ara h2-specific IgG4 observed at week 52 persisted to week 130. By a post hoc analysis, there were no statistically significant increases from week 52 to week 130 in either desensitization success or successfully consumed dose.

CONCLUSIONS

Extended treatment with VP250 was well tolerated, and desensitization observed at week 52 persisted between weeks 52 and 130. Treatment success was observed predominantly in younger participants, with younger age at initiation of active therapy an important predictor of success.

Weighing the benefits and risks of oral immunotherapy in clinical practice

Food allergies are common and affect 6-8% of children in the United States; they pose a significant burden on the quality of life of children with allergy and their caregivers due to multiple daily restrictions. Despite the recommended dietary avoidance, reactions tend to occur due to unintentional exposure to the allergenic food trigger. Fear of accidental ingestions with potentially severe reactions, including anaphylaxis and death, creates anxiety in individuals with food allergy. Oral immunotherapy has emerged as a form of active and potentially disease-modifying treatment for common food allergies encountered in childhood. The efficacy of oral immunotherapy is high, with the majority of participants achieving desensitization and, as a result, protection from trace exposures and improved quality of life. The main risk of oral immunotherapy consists of allergic reactions to treatment. In general, rates of allergic reactions and anaphylaxis are reported to be higher in individuals pursuing therapy options, but most subjects who undergo oral immunotherapy will likely experience mild or moderate reactions during treatment. Adverse events tend to reduce in both frequency and number in the maintenance period. The use of immune modulators alongside oral immunotherapy has been suggested, with the aim to improve efficacy and safety, and to facilitate the overall process. It is evident that the landscape of food allergy management is changing and that the future looks brighter, with different options emerging over time. The process of how to choose the appropriate option becomes a discussion between the clinician and the patient, which involves a joint review of the current medical evidence but also the patient's preference for balancing particular attributes of the treatment. By working together, providers and patients will ensure achievement of the best possible outcome for children with food allergies.

Use of biologics in food allergy management

Food allergies are a common medical problem, with children being the most affected patient group. The standard of care of food allergy consists of the acute treatment in case of a reaction and food avoidance in the long term, which influences the quality of life of patients. In this article, current developments for the causal treatment of food allergy including specific immunotherapy and biologics will be discussed. Epicutaneous and oral immunotherapy are currently in clinical development for the treatment of food allergy, and the results demonstrate good tolerability and efficacy with an increase in the oral threshold level. Biologics and, in particular, anti-IgE are currently investigated for their therapeutic use in food allergies. The results are promising, suggesting efficacy and tolerability.

Mucosal Nanoemulsion Allergy Vaccine Suppresses Alarmin Expression and Induces Bystander Suppression of Reactivity to Multiple Food Allergens

We have demonstrated that intranasal immunotherapy with allergens formulated in a nanoemulsion (NE) mucosal adjuvant suppresses Th2/IgE-mediated allergic responses and protects from allergen challenge in murine food allergy models. Protection conferred by this therapy is associated with strong suppression of allergen specific Th2 cellular immunity and increased Th1 cytokines. Here we extend these studies to examine the effect of NE-allergen immunization in mice sensitized to multiple foods. Mice were sensitized to both egg and peanut and then received NE vaccine formulated with either one or both of these allergens. The animals were then subjected to oral challenges with either egg or peanut to assess reactivity. Immunization with NE formulations containing both egg and peanut markedly reduced reactivity after oral allergen challenge with either allergen. Interestingly, mice that received the vaccine containing only peanut also had reduced reactivity to challenge with egg. Protection from oral allergen challenge was achieved despite the persistence of allergen-specific IgE and was associated with strong suppression of both Th2-polarized immune responses, alarmins and type 2 innate lymphoid cells (ILC2). NE-induced bystander suppression of reactivity required IFN-γ and the presence of an allergen in the NE vaccine. These results demonstrate that anaphylactic reactions to food allergens can be suppressed using allergen-specific immunotherapy without having to eliminate allergen-specific IgE and suggests that modulation of Th2 immunity towards one allergen may induce bystander effects that suppress reactivity to other allergens through the induction of IFN-γ and suppression of alarmins in the intestine. In addition, these data suggest that a NE vaccine for a single food allergen may lead to a global suppression of allergic responses to multiple foods.

Prevalence and characteristics of peanut allergy in US adults

BACKGROUND

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Insights into how innocuous foods or proteins deserving of immune ignorance can become allergens

Allergic disorders include food allergy, allergic rhinitis, and certain forms of asthma resulting from the inappropriate development of immune responses to otherwise innocuous aeroallergens and foods. In this issue of the JCI, Thouvenot and Roitel et al. explore transcription infidelity as a mechanism that underlies the ability of these benign proteins to become allergens. Some foods and bioaerosols that produce allergies have RNA polymerase with a propensity to generate RNA gaps, thereby causing translational frameshifts. These frameshifts often create cationic carboxy-terminus residues that replace hydrophobic amino acids and have enhanced MHC binding, resulting in the tendency to provoke immune responses. IgE antibody responses initiated by these variant transcripts can later lead to IgE against the native molecule and also explain how anaphylaxis may occur in individuals who lacked specific IgE when tested using native protein reagents. This study has the potential to transform the diagnosis and treatment of allergic disorders.

Novel vaccines for allergen-specific immunotherapy

PURPOSE OF REVIEW

Allergen-specific immunotherapy (AIT) is a highly economic, effective and disease-modifying form of allergy treatment but requires accurate prescription and monitoring. New molecular approaches are currently under development to improve AIT by reducing treatment-related side effects, cumbersome protocols and patients' compliance. We review the current advances regarding refined diagnosis for prescription and monitoring of AIT and the development of novel molecular vaccines for AIT. Finally, we discuss prophylactic application of AIT.

RECENT FINDINGS

There is evidence that molecular allergy diagnosis not only assists in the prescription and monitoring of AIT but also allows a refined selection of patients to increase the likelihood of treatment success. New data regarding the effects of AIT treatment with traditional allergen extracts by alternative routes have become available. Experimental approaches for AIT, such as virus-like particles and cell-based treatments have been described. New results from clinical trials performed with recombinant hypoallergens and passive immunization with allergen-specific antibodies highlight the importance of allergen-specific IgG antibodies for the effect of AIT and indicate opportunities for preventive allergen-specific vaccination.

SUMMARY

Molecular allergy diagnosis is useful for the prescription and monitoring of AIT and may improve the success of AIT. Results with molecular allergy vaccines and by passive immunization with allergen-specific IgG antibodies indicate the importance of allergen-specific IgG capable of blocking allergen recognition by IgE and IgE-mediated allergic inflammation as important mechanism for the success of AIT. New molecular vaccines may pave the road towards prophylactic allergen-specific vaccination.

Recent advances in the management of nut allergy

Peanut/tree nut allergy is common and has been associated with particularly severe reactions. Epidemiological data have shown that the prevalence ranges between 0.05% and 4.9% for tree nut and between 0.5% and 3% for peanut. These large variations can be explained by differences in the age of included patients and the geographical region. In addition, the food consumption modality (ie, raw versus roasted) plays a major role, as heat treatment has the capacity to modify the allergenicity of nuts and legumes. Nut allergies tend to persist into adulthood and consequently have a high impact on quality of life.

Recently, it has been demonstrated that a significant proportion of nut allergic patients are able to tolerate other nuts. As opposed to the avoidance of all nuts, this approach is currently proposed in several tertiary allergy centers. However, diagnosis of nut allergy is particularly difficult due to co-sensitization leading to high rate of false positive skin prick tests and/or specific IgE to whole allergen extracts. The use of component resolved diagnosis leads to major improvement of diagnosis, particularly to distinguish between primary and secondary nut allergies. The basophil activation test has been suggested to be useful but is still used mainly as a research tool. Thus, diagnosis remains mainly based on the oral food challenge, which is considered as the gold standard.

Regarding treatment, avoidance remains the cornerstone of management of nut allergy. Oral immunotherapy is increasingly proposed as an alternative management strategy.

IgE-Mediated Peanut Allergy: Current and Novel Predictive Biomarkers for Clinical Phenotypes Using Multi-Omics Approaches

Food allergy is a collective term for several immune-mediated responses to food. IgE-mediated food allergy is the best-known subtype. The patients present with a marked diversity of clinical profiles including symptomatic manifestations, threshold reactivity and reaction kinetics. In-vitro predictors of these clinical phenotypes are evasive and considered as knowledge gaps in food allergy diagnosis and risk management. Peanut allergy is a relevant disease model where pioneer discoveries were made in diagnosis, immunotherapy and prevention. This review provides an overview on the immune basis for phenotype variations in peanut-allergic individuals, in the light of future patient stratification along emerging omic-areas. Beyond specific IgE-signatures and basophil reactivity profiles with established correlation to clinical outcome, allergenomics, mass spectrometric resolution of peripheral allergen tracing, might be a fundamental approach to understand disease pathophysiology underlying biomarker discovery. Deep immune phenotyping is thought to reveal differential cell responses but also, gene expression and gene methylation profiles (eg, peanut severity genes) are promising areas for biomarker research. Finally, the study of microbiome-host interactions with a focus on the immune system modulation might hold the key to understand tissue-specific responses and symptoms. The immune mechanism underlying acute food-allergic events remains elusive until today. Deciphering this immunological response shall enable to identify novel biomarker for stratification of patients into reaction endotypes. The availability of powerful multi-omics technologies, together with integrated data analysis, network-based approaches and unbiased machine learning holds out the prospect of providing clinically useful biomarkers or biomarker signatures being predictive for reaction phenotypes.

Current Insights into Immunotherapy Approaches for Food Allergy

In the last decade, there has been increasing research dedicated to food immunotherapy to induce clinical desensitization and provide protection by increasing clinical reaction thresholds. Results from recent food immunotherapy studies with differing routes of administration (oral, sublingual, and epicutaneous) suggest that food immunotherapy can induce clinical desensitization with varying levels of safety, however lasting tolerance has not been demonstrated. Furthermore, treatment side effects and dosing logistics may make the therapies difficult for some supporting the need for alternative treatment approaches. Peptide immunotherapy and DNA vaccine approaches should in theory allow for safer administration by decreasing allergenicity but proof of their clinical efficacy and immunogenicity remains to be proven. Biologic agents may allow for increased safety and rapid up-dosing of immunotherapy with the added benefit of treating multiple allergens simultaneously.

Patients' Perspectives and Needs on Novel Food Allergy Treatments in the United States

PURPOSE

Food allergy management places a daily psychosocial burden on patients and their caregivers. New food allergy treatments may positively impact their lives, but also introduce new stressors. The purpose of this paper is to provide an overview of the current state of the literature regarding patients' and caregivers' food allergy experiences and needs within the United States as well as a set of recommendations regarding how best to proceed with patient-centered development and evaluation of new food allergy treatments.

RECENT FINDINGS

The first pharmaceutical-grade product for peanut oral immunotherapy was approved in the United States for children aged 4-17 years following a successful international Phase 3 trial. This new treatment is only the first of several food allergy treatments currently under development. Patients will soon be presented with multiple options for food allergy treatment and will need to make decisions about what treatment is best for them.

SUMMARY

Allergy researchers and providers are encouraged to consider patients' perspectives and needs when developing and evaluating new food allergy treatments. Recommendations regarding next steps include the development of new patient-reported outcome tools, focus on psychosocial support, health disparities, and financial implications, and research harmonization and interdisciplinary collaboration.

Severity grading system for acute allergic reactions: A multidisciplinary Delphi study

BACKGROUND

There is no widely adopted severity grading system for acute allergic reactions, including anaphylactic and nonanaphylactic reactions, thus limiting the ability to optimize and standardize management practices and advance research.

OBJECTIVE

The aim of this study was to develop a severity grading system for acute allergic reactions for use in clinical care and research.

METHODS

From May to September 2020, we convened a 21-member multidisciplinary panel of allergy and emergency care experts; 9 members formed a writing group to critically appraise and assess the strengths and limitations of prior severity grading systems and develop the structure and content for an optimal severity grading system. The entire study panel then revised the grading system and sought consensus by utilizing Delphi methodology.

RESULTS

The writing group recommended that an optimal grading system encompass the severity of acute allergic reactions on a continuum from mild allergic reactions to anaphylactic shock. Additionally, the severity grading system must be able to discriminate between clinically important differences in reaction severity to be relevant in research while also being intuitive and straightforward to apply in clinical care. Consensus was reached for all elements of the proposed severity grading system.

CONCLUSION

We developed a consensus severity grading system for acute allergic reactions, including anaphylactic and nonanaphylactic reactions. Successful international validation, refinement, dissemination, and application of the grading system will improve communication among providers and patients about the severity of allergic reactions and will help advance future research.

Fecal microbiome and metabolome differ in healthy and food-allergic twins

BACKGROUNDThere has been a striking generational increase in the prevalence of food allergies. We have proposed that this increase can be explained, in part, by alterations in the commensal microbiome.METHODSTo identify bacterial signatures and metabolic pathways that may influence the expression of this disease, we collected fecal samples from a unique, well-controlled cohort of twins concordant or discordant for food allergy. Samples were analyzed by integrating 16S rRNA gene amplicon sequencing and liquid chromatography-tandem mass spectrometry metabolite profiling.RESULTSA bacterial signature of 64 operational taxonomic units (OTUs) distinguished healthy from allergic twins; the OTUs enriched in the healthy twins were largely taxa from the Clostridia class. We detected significant enrichment in distinct metabolite pathways in each group. The enrichment of diacylglycerol in healthy twins is of particular interest for its potential as a readily measurable fecal biomarker of health. In addition, an integrated microbial-metabolomic analysis identified a significant association between healthy twins and Phascolarctobacterium faecium and Ruminococcus bromii, suggesting new possibilities for the development of live microbiome-modulating biotherapeutics.CONCLUSIONTwin pairs exhibited significant differences in their fecal microbiomes and metabolomes through adulthood, suggesting that the gut microbiota may play a protective role in patients with food allergies beyond the infant stage.TRIAL REGISTRATIONParticipants in this study were recruited as part of an observational study (ClinicalTrials.gov NCT01613885) at multiple sites from 2014 to 2018.FUNDINGThis work was supported by the Sunshine Charitable Foundation; the Moss Family Foundation; the National Institute of Allergy and Infectious Diseases (NIAID) (R56AI134923 and R01AI 140134); the Sean N. Parker Center for Allergy and Asthma Research; the National Heart, Lung, and Blood Institute (R01 HL 118612); the Orsak family; the Kepner family; and the Stanford Institute for Immunity, Transplant and Infection.

Integrating oral immunotherapy into clinical practice

In 2020, the first food allergy treatment, an oral immunotherapy (OIT) product for peanut allergy, was approved by the Food and Drug Administration, and a peanut epicutaneous immunotherapy patch was under review. As food allergy therapies become available and widespread, allergy offices will need to adjust practices to be able to offer their patients these new treatments. OIT is an intensive therapy that requires commitment from patients and their families, and open communication with the practice is paramount. OIT may not be the right therapy for every patient, and although identifying good candidates is still an area rich for research opportunity, experience from cohorts and clinical trials provides some insight. It is important to understand the scope of practice for each member of the OIT team based on state regulations for a particular location. Staffing and space will likely dictate how many patients at an individual office could be on active OIT at one time. Emergency medications, supplies, and protocols must be in place. Screening, scheduling, visit procedures, monitoring, home dosing, dose modifications, safety precautions, adverse reactions, and maintenance will be addressed in this article. Finally, adjunct therapies under investigation will be reviewed.

Irradiated Tree Nut Flours for Use in Oral Immunotherapy

BACKGROUND

Tree nut allergies affect an estimated 1% of the US population and is lifelong in 90% of allergic individuals. Oral immunotherapy (OIT) for food allergies is an effective method to induce desensitization in a majority of participants in trials of peanut, egg, and milk OIT. Limited trials using tree nut OIT have been reported, possibly due to the lack of standardized drug products.

OBJECTIVE

Food products used in OIT are considered drugs by the Food and Drug Administration (FDA) because they are intended to modulate the individuals' immune responses to the food allergens. As such, OIT drug products must meet FDA standards for acceptable levels of microbes and undergo testing for allergenic proteins. We aimed to determine the suitability of walnut, cashew, hazelnut, and almond flours for use in OIT trials.

METHODS

We employed gamma irradiation on commercially available walnut, cashew, hazelnut, and almond flours and tested their levels of microbial contamination, total protein, and allergen content, along with stability of these parameters over time.

RESULTS

Our results demonstrate that irradiation of tree nut flours greatly diminishes the levels of total aerobic bacteria, mold, yeast, Escherichia coli, and Salmonella, whereas there are no substantial changes in total protein or allergen content. Importantly, the microbial levels, protein, and allergen content remained stable over a 24-month period.

CONCLUSION

Irradiation of tree nut flours is a safe and effective method of processing to allow tree nut products to meet the FDA standards for OIT drug products.

Diagnosis of Peanut Allergy in Preschool Children: The Impact of Skin Testing With a Novel Composition of Peanuts

Peanut allergy is an increasing concern in younger children. Available bedside diagnostic tools, i.e., prick tests with commercial extracts or peanut-containing foods have only limited predictive values. In a cohort of preschoolers with both a history of allergic reactions and sensitization to peanut proteins, we aimed to characterize the impact of skin tests with a novel composition of peanuts LPP-MH. Almost one quarter (27/110) of preschool children, with a history of allergic reactions to peanuts and positive standard IgE-mediated tests for peanut allergy, can tolerate the reintroduction of peanut proteins into their diet after resolving their allergy and, thus, can avoid adverse health outcomes associated with the false diagnosis. In the younger age group, a quarter of peanut allergic children, display a relatively high threshold, potentially enabling an easier and safer oral immunotherapy protocol in this window of opportunity in childhood. The use of the novel diagnostic skin test, LPP-MH, significantly improves the predictive value of outpatient evaluation for the outcomes of peanut challenge as well as the expected threshold at which the PA child will react, thus, making for a better informed decision of how, when, and where to challenge.

Advancing Food Allergy Through Omics Sciences

Since the publication of the first draft of the human genome, there has been an explosion of new technologies with increasing power to interrogate the totality of biological molecules (eg, DNA, RNA, proteins, metabolites) and their modifications (eg, DNA methylation, histone modifications). These technologies, collectively called omics, have been widely applied in the last 2 decades to study biological systems to gain deeper insight into mechanisms driving the physiology and pathophysiology of human health and disease. Because of its complex, multifactorial nature, food allergy is especially well suited to be investigated using omics approaches. In this rostrum, we review how omic technologies have been applied to explore diverse aspects of food allergy, including adaptive and innate immune processes in food-allergic responses, the role of the microbiome in food allergy risk, metabolic changes in the gut and blood associated with food allergy, and the identification of biomarkers and potential therapeutic targets for the condition. We discuss the strengths and limitations of the studies performed thus far and the need to adopt systems biology approaches that integrate data from multiple omics to fully leverage the potential of these technologies to advance food allergy research and care.

IL-4-BATF signaling directly modulates IL-9 producing mucosal mast cell (MMC9) function in experimental food allergy

BACKGROUND

This study group has previously identified IL-9-producing mucosal mast cell (MMC9) as the primary source of IL-9 to drive intestinal mastocytosis and experimental IgE-mediated food allergy. However, the molecular mechanisms that regulate the expansion of MMC9s remain unknown.

OBJECTIVES

This study hypothesized that IL-4 regulates MMC9 development and MMC9-dependent experimental IgE-mediated food allergy.

METHODS

An epicutaneous sensitization model was used and bone marrow reconstitution experiments were performed to test the requirement of IL-4 receptor α (IL-4Rα) signaling on MMC9s in experimental IgE-mediated food allergy. Flow cytometric, bulk, and single-cell RNA-sequencing analyses on small intestine (SI) MMC9s were performed to illuminate MMC9 transcriptional signature and the effect of IL-4Rα signaling on MMC9 function. A bone marrow-derived MMC9 culture system was used to define IL-4-BATF signaling in MMC9 development.

RESULTS

Epicutaneous sensitization- and bone marrow reconstitution-based models of IgE-mediated food allergy revealed an IL-4 signaling-dependent cell-intrinsic effect on SI MMC9 accumulation and food allergy severity. RNA-sequencing analysis of SI-MMC9s identified 410 gene transcripts reciprocally regulated by IL-4 signaling, including Il9 and Batf. Insilico analyses identified a 3491-gene MMC9 transcriptional signature and identified 2 transcriptionally distinct SI MMC9 populations enriched for metabolic or inflammatory programs. Employing an in vitro MMC9-culture model system showed that generation of MMC9-like cells was induced by IL-4 and this was in part dependent on BATF.

CONCLUSIONS

IL-4Rα signaling directly modulates MMC9 function and exacerbation of experimental IgE-mediated food allergic reactions. IL-4Rα regulation of MMC9s is in part BATF-dependent and occurs via modulation of metabolic transcriptional programs.

Model of Walnut Allergy in CC027/GeniUnc Mice Recapitulates Key Features of Human Disease

Tree nut allergies affect 1% of the United States population, are often severe in nature and rarely outgrown. Despite the severity and prevalence, there are no FDA-approved treatments for tree nut allergy. Development of a therapeutic would be expedited by having a mouse model that mimics the human disease. We utilized the CC027/GeniUnc mouse strain, which was previously identified as an orally reactive model of peanut allergy, to develop a model of walnut allergy. Mice were sensitized with walnut and cholera toxin for 4 weeks and subsequently challenged by oral gavage. Blood samples were collected to measure serum IgE. Walnut-sensitized mice produced high levels of walnut-IgE and were cross-sensitized to pecan. Oral challenges with walnut resulted in severe anaphylaxis and accompanying allergic symptoms. Importantly, pecan challenges also led to severe allergic reactions, indicating cross-reactivity to pecan. Overall, this novel mouse model reproduces key characteristics of human walnut allergy, which provides a platform to develop novel therapies and better understand sensitization mechanisms.

A High Proportion of Canadian Allergists Offer Oral Immunotherapy but Barriers Remain

BACKGROUND

Limited data on clinical implementation of oral immunotherapy (OIT) have been reported with incomplete evaluation of barriers.

OBJECTIVE

To survey Canadian allergists on their current practice of OIT and barriers to implementation and expansion of OIT.

METHODS

A survey investigating current practice and logistical and clinical barriers to offering or expanding OIT was distributed to all Canadian Society of Allergy and Clinical Immunology allergists.

RESULTS

Of 90 responding allergists, 52.2% reported offering OIT, most commonly to peanut. Food sublingual immunotherapy was offered by 7% of allergists. Having received training for OIT was associated with currently performing OIT (P = .008); 44.7% of allergists offering OIT had received training on OIT, and 81.4% not offering OIT had no training. A total of 87% of allergists performing OIT reported lack of efficacy data and lack of support staff and clinic space, and concerns about increased oral challenges (84%) were "moderately" to "extremely" important barriers to expanding OIT. For clinicians not offering OIT, concerns about safety (95%), after-hours support (95%), efficacy (93%), medicolegal risk (93%), and long-term practice implications (93%) were prioritized as significant barriers. Qualitative assessment suggested concerns about the practical challenges associated with OIT, the need for increased safety and efficacy data, and a desire for OIT guidelines and training.

CONCLUSION

The implementation of OIT faces many barriers, both clinical and logistical. Increasing high-quality safety and efficacy data may support those hesitant to offer OIT, and improving funding may address the practical infrastructure challenges. In addition, training will help expand access for allergists interested in performing OIT.

Continuous and Daily Oral Immunotherapy for Peanut Allergy: Results from a 2-Year Open-Label Follow-On Study

BACKGROUND

The randomized, controlled PALISADE trial demonstrated the benefit of daily oral immunotherapy with Peanut (Arachis Hypogaea) allergen powder-dnfp (PTAH, formerly AR101) in peanut-allergic children and adolescents.

OBJECTIVE

ARC004, the open-label follow-on study to PALISADE, used 5 dosing cohorts to explore PTAH treatment beyond 1 year and alternative dosing regimens in peanut-allergic individuals.

METHODS

Active arm (PTAH-continuing) PALISADE participants who tolerated 300-mg peanut protein at the exit double-blind placebo-controlled food challenge and placebo arm (PTAH-naive) participants could enter ARC004. PTAH-continuing participants were assigned to receive daily (cohorts 1 and 3A) or non-daily (cohorts 2, 3B, and 3C) dosing regimens; PTAH-naive participants were built up to 300 mg/d PTAH, followed by maintenance dosing. At study completion, participants underwent an exit double-blind placebo-controlled food challenge with doses up to 2000 mg peanut protein. Data were assessed using descriptive statistics.

RESULTS

Overall, 358 (87.5%) eligible participants (4-17 years) entered ARC004 (PTAH-continuing, n = 256; PTAH-naive, n = 102). Among PTAH-continuing participants, exposure-adjusted adverse event rates were 12.94 to 17.54/participant-year and 25.95 to 42.49/participant-year in daily and non-daily dosing cohorts, respectively; most participants (83%) experienced mild or moderate adverse events. Daily dosing cohorts appeared to have higher desensitization rates than non-daily dosing cohorts. Of all PTAH-continuing cohorts, cohort 3A had the longest daily dosing duration and the highest desensitization rates. Changes in immune markers with PTAH continuation demonstrated ongoing immunomodulation. Outcomes in PTAH-naive participants mirrored those of the PALISADE active arm.

CONCLUSIONS

Continued daily PTAH treatment beyond 1 year showed sustained safety and efficacy. Ongoing immunomodulation was observed during the second year of treatment.

A study to assess current approaches of allergists in European countries diagnosing and managing children and adolescents with peanut allergy

RATIONALE

Food allergy is documented to result in considerable morbidity, negative impact on quality of life, and substantial medical care costs. Although anecdotal data suggest widely varying practices in the diagnosis and management of food allergies, the diversity and relative frequency of these practices have not been documented.

METHODS

A questionnaire was developed evaluating allergists' management approaches of individuals with peanut allergy (PA) in Germany (DE), France (FR), and the United Kingdom (UK).

RESULTS

Here, we report the survey results from a total of 109 allergists from DE, FR and the UK. They reported to confirm PA at initial diagnosis using skin prick test (≥60%), while allergists from DE and FR reported using allergen-specific IgE testing more (>86%) compared to the UK (<50%). At initial diagnosis, oral food challenge was used less in DE (13%) and FR (14%) and very rarely in the UK (3%) to confirm diagnosis. Recognition of acute reactions, use of adrenaline auto-injectors and allergen avoidance were reported to be discussed with the patient/caregiver at the initial office visit by most allergists (>75%). Half of the responders reported assessing the patient's quality of life. 63% allergists reported retesting for PA resolution at a later date, with 45% allergists indicated to recommend ingestion of a normal serving of peanut regularly upon resolution. Lack of effective PA treatment was reported to be a 'very significant' barrier for optimal PA treatment, with allergists being less than 'moderately familiar' with data from clinical trials testing new treatments options for PA. Lastly, allergists stated that the severity of patient's PA ranked as the most important factor in their decision to recommend oral immunotherapy for PA treatment.

CONCLUSIONS

This survey provides essential insights into the practice of allergists and highlights some areas that would inform strategies for education and improving PA healthcare.

Biomarkers for diagnosis and prediction of therapy responses in allergic diseases and asthma

Modern health care requires a proactive and individualized response to diseases, combining precision diagnosis and personalized treatment. Accordingly, the approach to patients with allergic diseases encompasses novel developments in the area of personalized medicine, disease phenotyping and endotyping, and the development and application of reliable biomarkers. A detailed clinical history and physical examination followed by the detection of IgE immunoreactivity against specific allergens still represents the state of the art. However, nowadays, further emphasis focuses on the optimization of diagnostic and therapeutic standards and a large number of studies have been investigating the biomarkers of allergic diseases, including asthma, atopic dermatitis, allergic rhinitis, food allergy, urticaria and anaphylaxis. Various biomarkers have been developed by omics technologies, some of which lead to a better classification of distinct phenotypes or endotypes. The introduction of biologicals to clinical practice increases the need for biomarkers for patient selection, prediction of outcomes and monitoring, to allow for an adequate choice of the duration of these costly and long‐lasting therapies. Escalating healthcare costs together with questions about the efficacy of the current management of allergic diseases require further development of a biomarker‐driven approach. Here, we review biomarkers in diagnosis and treatment of asthma, atopic dermatitis, allergic rhinitis, viral infections, chronic rhinosinusitis, food allergy, drug hypersensitivity and allergen immunotherapy with a special emphasis on specific IgE, the microbiome and the epithelial barrier. In addition, EAACI guidelines on biologicals are discussed within the perspective of biomarkers.

Eosinophils in Eosinophilic Esophagitis: The Road to Fibrostenosis is Paved With Good Intentions

Eosinophilic esophagitis (EoE) is an antigen-driven disease associated with epithelial barrier dysfunction and chronic type 2 inflammation. Eosinophils are the defining feature of EoE histopathology but relatively little is known about their role in disease onset and progression. Classically defined as destructive, end-stage effector cells, eosinophils (a resident leukocyte in most of the GI tract) are increasingly understood to play roles in local immunity, tissue homeostasis, remodeling, and repair. Indeed, asymptomatic esophageal eosinophilia is observed in IgE-mediated food allergy. Interestingly, EoE is a potential complication of oral immunotherapy (OIT) for food allergy. However, we recently found that patients with peanut allergy may have asymptomatic esophageal eosinophilia at baseline and that peanut OIT induces transient esophageal eosinophilia in most subjects. This is seemingly at odds with multiple studies which have shown that EoE disease severity correlates with tissue eosinophilia. Herein, we review the potential role of eosinophils in EoE at different stages of disease pathogenesis. Based on current literature we suggest the following: (1) eosinophils are recruited to the esophagus as a homeostatic response to epithelial barrier disruption; (2) eosinophils mediate barrier-protective activities including local antibody production, mucus production and epithelial turnover; and (3) when type 2 inflammation persists, eosinophils promote fibrosis.

First Real-World Effectiveness Analysis of Preschool Peanut Oral Immunotherapy

BACKGROUND

We previously described safety of preschool peanut oral immunotherapy (P-OIT) in a real-world setting; 0.4% of patients experienced a severe reaction, and 4.1% received epinephrine, during build-up.

OBJECTIVE

To determine the effectiveness of preschool P-OIT after 1 year of maintenance.

METHODS

Preschoolers (9-70 months) with at least 1 objective reaction to peanut (during baseline oral food challenge (OFC) or P-OIT build-up) received a follow-up OFC to cumulative 4000 mg protein after 1 year on 300 mg peanut daily maintenance. Effectiveness of desensitization was defined as proportion of patients with a negative follow-up OFC. Symptoms and treatment at follow-up OFC were recorded.

RESULTS

Of the 117 patients who successfully completed 1 year of P-OIT and subsequently underwent a cumulative 4000-mg follow-up OFC, 92 (78.6%) had a negative OFC and 115 (98.3%) tolerated a cumulative dose of greater than or equal to 1000 mg. For the 25 (21.4%) who reacted, their threshold increased by 3376 mg (95% CI, 2884-3868) from baseline to follow-up; 17 (14.5%) patients experienced grade 1 reactions, 7 (6.00%) grade 2, and 1 (0.85%) grade 3. Two patients (1.71%) received epinephrine associated with P-OIT, and 1 (0.85%) went to the emergency department.

CONCLUSIONS

Our data demonstrate that real-world preschool P-OIT is effective after 1 year of maintenance for those who received a follow-up OFC. For those who reacted, their threshold increased sufficiently to protect against accidental exposures. P-OIT should be considered for preschoolers as an alternative to current recommendations to avoid peanut.

Eosinophilic Esophagitis as a Side Effect of Food Oral Immunotherapy

Food allergies (FAs) include a spectrum of immune-mediated serious and potentially life-threatening medical conditions with an overall estimated prevalence ranging from 4% to 8% in the U.S. and Europe. Significant progress in food allergen-specific immunotherapy has been accomplished over the past 10 years. The most studied strategy has been oral immunotherapy (OIT), also known as food desensitization, a treatment in which a child is slowly and deliberately given a small amount of the food to ingest (that previously was a food allergy trigger) with the ultimate goal of the child eating that food without a reaction. OIT is now recommended in the European guidelines for the treatment of milk, egg, and peanut allergies and was the first American Food Drug Administration (FDA) approved product for the prevention of severe reaction to peanuts in 4–17 year olds to be released on the market. The side effects associated with OIT treatment trials are mild to moderate, predominantly oropharyngeal, and easily treated. More severe reactions, such as generalized urticaria/angioedema, wheezing/respiratory distress, laryngeal edema, and repetitive emesis, have been reported. However systemic reactions are very rare. Low-dose immunotherapy is associated with significantly fewer side effects. Currently, its most limiting allergic side effect is that approximately 10–15% of subjects treated with OIT experience gastrointestinal symptoms, preventing the continuation of therapy. Eosinophilic esophagitis (EoE) has also been reported as a cause of persistent abdominal symptoms in OIT.

Role of orally induced regulatory T cells in immunotherapy and tolerance

Oral antigen administration to induce regulatory T cells (Treg) takes advantage of regulatory mechanisms that the gastrointestinal tract utilizes to promote unresponsiveness against food antigens or commensal microorganisms. Recently, antigen-based oral immunotherapies (OITs) have shown efficacy as treatment for food allergy and autoimmune diseases. Similarly, OITs appear to prevent anti-drug antibody responses in replacement therapy for genetic diseases. Intestinal epithelial cells and microbiota possibly condition dendritic cells (DC) toward a tolerogenic phenotype that induces Treg via expression of several mediators, e.g. IL-10, transforming growth factor-β, retinoic acid. Several factors, such as metabolites derived from microbiota or diet, impact the stability and expansion of these induced Treg, which include, but are not limited to, FoxP3⁺ Treg, LAP⁺ Treg, and/or Tr1 cells. Here, we review various orally induced Treg, their plasticity and cooperation between the Treg subsets, as well as underlying mechanisms controlling their induction and role in oral tolerance.

Emerging Therapies for Peanut Allergy

Peanut allergy (PA) is a food allergy that causes an IgE-mediated type I hypersensitivity reaction. PA has become an increasing public health burden, with 2% of American children reported to have this condition in 2010. Current guidelines recommend allergen avoidance, patient education, and administration of H1 antihistamines, β2-agonists, or epinephrine based on the severity of reaction. In this review article, emerging therapies for PA are evaluated for their potential role in treating PA. Oral, epicutaneous, and sublingual immunotherapies have completed clinical trials with promising efficacy. In particular, Palforzia (AR101) is an oral immunotherapy that received Food and Drug Administration (FDA)-approval in January 2020 and Viaskin Peanut is an epicutaneous immunotherapy with an anticipated FDA decision date by August 5, 2020. Furthermore, adjuvant combinations with either probiotics or anti-IgE receptor antagonists have shown an improved efficacy and safety profile compared to oral immunotherapy alone. However, immunotherapy-induced adverse reaction rates are high due to the risks associated with intentional allergen exposure. These results suggest that peanut immunotherapy has a promising role in the treatment of PA, although further studies are needed before its incorporation into standard of care.

Immunological Outcomes of Allergen-Specific Immunotherapy in Food Allergy

IgE-mediated food allergies are caused by adverse immunologic responses to food proteins. Allergic reactions may present locally in different tissues such as skin, gastrointestinal and respiratory tract and may result is systemic life-threatening reactions. During the last decades, the prevalence of food allergies has significantly increased throughout the world, and considerable efforts have been made to develop curative therapies. Food allergen immunotherapy is a promising therapeutic approach for food allergies that is based on the administration of increasing doses of culprit food extracts, or purified, and sometime modified food allergens. Different routes of administration for food allergen immunotherapy including oral, sublingual, epicutaneous and subcutaneous regimens are being evaluated. Although a wealth of data from clinical food allergen immunotherapy trials has been obtained, a lack of consistency in assessed clinical and immunological outcome measures presents a major hurdle for evaluating these new treatments. Coordinated efforts are needed to establish standardized outcome measures to be applied in food allergy immunotherapy studies, allowing for better harmonization of data and setting the standards for the future research. Several immunological parameters have been measured in food allergen immunotherapy, including allergen-specific immunoglobulin levels, basophil activation, cytokines, and other soluble biomarkers, T cell and B cell responses and skin prick tests. In this review we discuss different immunological parameters and assess their applicability as potential outcome measures for food allergen immunotherapy that may be included in such a standardized set of outcome measures.

[Immunotherapy of allergies: current status]

Allergen immunotherapy (AIT) is the only causally effective, disease-modifying form of therapy that, in addition to alleviating allergic symptoms, counteracts disease progression.This article provides an up-to-date overview of immunological, regulatory and practical aspects of AIT. Current literature was included and recent conceptual regulatory developments from the Division of Allergology at the higher federal authority (Paul-Ehrlich-Institut) are presented.The 62 AIT products currently approved in Germany and further 61 AIT products under the development program of the Therapy Allergen Ordinance (TAO) include 95 products for subcutaneous (SCIT) and 28 for sublingual (SLIT) treatment of birch/alder/hazel pollen, grass pollen, weed pollen, house dust mite and insect venom allergies. Native and chemically modified allergen extracts (allergoids) adsorbed to aluminium, tyrosine (partly monophosphoryl lipid A-adjuvanted) or lactose or based on lyophilisates are used as active ingredients.These 123 AIT products are subject to official state batch release testing. This does not apply to named patient products (NPPs) available for the treatment of less prevalent allergies (e.g. to olive pollen, animal hair, storage mites or moulds). There is a particular need for development of AIT products for children.As a new class of active ingredients, food allergens are in clinical phase II and III studies. A first food preparation for oral AIT of peanut allergy in children is currently undergoing a central European marketing authorization (MA) procedure. MA can only be granted if the benefit-risk balance is positive. Science and regulation are in continuous exchange on the development of AIT products that correspond to the current state of clinical research and regulation in the EU and enable early causal treatment of widespread allergies.

Novel insights regarding anaphylaxis in children - With a focus on prevalence, diagnosis, and treatment

Anaphylaxis is a serious allergic reaction that occurs rapidly and causes a life-threatening response involving the whole body. This reaction often leads to difficulty in breathing and can result in death. The estimated prevalence of anaphylaxis is 0.05%-2%, which is reported to be increasing in children. Although drugs and venom are the most common causes of anaphylaxis in adults, food is the most common cause of anaphylaxis in children. An interesting association between food-dependent exercise-induced anaphylaxis (FDEIA) and oral immunotherapy (OIT) has recently been reported. A provocation test to determine the diagnostic and augmenting factors of FDEIA has been reported in recent years. Remarkably, several articles showed allergic symptoms without exercise in children with FDEIA and in those with FDEIA development after OIT. Regarding OIT, full-dose OIT poses a risk of adverse reactions, including anaphylaxis. Recent trials have shown the efficacy and safety of low-dose OIT in patients with food-induced anaphylaxis. In this review, we summarized the novel insights regarding anaphylaxis in the pediatric population.

Can Microbes Boost Tregs to Suppress Food Sensitivities?

Food sensitivities are on the rise worldwide. Peripheral induced regulatory T cells (pTreg cells) play a central role in oral tolerance to dietary antigens and can contribute to preventing the onset of immune-mediated food sensitivities. Here, we discuss the potential of microbial-derived products in promoting pTreg cell proliferation for re-establishing oral tolerance in immune-mediated food sensitivities.

Evaluation of oral immunotherapy efficacy and safety by maintenance dose dependency: A multicenter randomized study

Background

Generally, oral immunotherapy (OIT) aims for daily administration. Recently, the efficacy of treatment with OIT at a low dose has been reported. However, the optimal dose and the evaluation of dose-dependent OIT outcome have not been described.

Methods

A multicenter, parallel, open-labeled, prospective, non-placebo controlled, randomized study enrolled 101 Japanese patients for treatment with OIT. We hypothesized that target dose OIT would induce short-term unresponsiveness (StU) earlier than reduced dose OIT. StU was defined as no response to 6200 mg whole egg, 3400 mg milk, and 2600 mg wheat protein, as evaluated by oral food challenge after 2-week ingestion cessation. To compare the two doses of OIT efficacy, the maximum ingestion doses during the maintenance phase of OIT were divided into 100%-dose or 25%-dose groups against their target StU dose, respectively. A total of 51 patients were assigned to the 100%-dose group [hen's egg (HE) = 26, cow's milk (CM) = 13, wheat = 12] and 50 to the 25%-dose group (HE = 25, CM = 13, wheat = 12). Primary outcome was established by comparing StU at 1 year. Secondary outcome was StU at 2 years and established by comparing allergic symptoms and immunological changes.

Results

The year 1 StU rates (%) for the 100%- and 25%-dose groups were 26.9 vs. 20.0 (HE), 7.7 vs. 15.4 (CM), and 50.0 vs. 16.7 (wheat), respectively. The year 2 StU rates were 30.8 vs. 36.0 (HE), 7.7 vs. 23.1 (CM), and 58.3 vs. 58.3 (wheat), respectively. There were no statistically significant differences in StU between years 1 and 2. The total allergic symptom rate in the 25%-dose group was lower than that in the 100%-dose group for egg, milk, and wheat. Antigen-specific IgE levels for egg-white, milk, and wheat decreased at 12 months.

Conclusions

Reduced maintenance dose of egg OIT showed similar therapeutic efficacy to the target dose. However, we were not able to clearly demonstrate the efficacy, particularly for milk and wheat. Reducing the maintenance dose for eggs, milk, and wheat may effectively lower the symptoms associated with their consumption compared to the target OIT dose. Furthermore, aggressive reduction of the maintenance dose might be important for milk and wheat, compared to the 25%-dose OIT.

Trial registration

UMIN000009373, Multicenter Oral Immunotherapy for Hen's Egg, Cow's Milk, and Wheat-Allergic Children at Outpatient Clinic.

Oral immunotherapy for peanut allergy: The con argument

Background

In some countries of the world, peanut allergy represents an important source of anaphylactic reactions. Traditionally treated with the avoidance of responsible allergens, this condition can also be targeted by oral peanut immunotherapy.

Methods

In this study, we review the beneficial and side effects of currently available forms of peanut oral immunotherapy (POIT). We report the discussions resulting from the publication of a meta-analysis that brought to light the downsides of oral immunotherapy for peanuts.

Results

In some clinical situations, the risk-benefit ratio can favor peanut oral immunotherapy over avoidance. In many other situations, this is not the case. The decision must be based on the values and preferences of clinicians and patients. Those not ready to accept serious adverse effects from POIT are likely to continue the elimination diet; those motivated to achieving desensitization, and prepared to accept serious adverse effects, may choose to undergo POIT.

Conclusions

Without being prejudiced against peanut oral immunotherapy, we indicate the possible evolution of treatment for this condition is in a rapidly evolving broader scenario. Among the future options, sublingual immunotherapy, parenteral immunotherapy with modified allergens, transcutaneous immunotherapy, and the use of biologics will become important options.

Oral immunotherapy for peanut allergy: The pro argument

Food allergy (FA) is a growing public health problem with personal, social, nutritional, and economic consequences. In the United States, it is estimated that 8% of children and 10.8% of adults have food allergies. Allergies to peanuts are particularly worrisome as unlike allergies to other allergenic foods, such as milk and egg, which are commonly outgrown by 5 or 10 years of age, 80% of peanut allergies persist into adulthood. The first drug for peanut allergy, Palforzia, was approved by the US Food and Drug Administration (FDA) in January 2020. For other food allergies, the current standard of care for the management of FA is suboptimal and is limited to dietary elimination of the offending allergen, vigilance against accidental ingestion, and treatment of allergic reactions with antihistamines and epinephrine. However, dietary avoidance can be challenging, and it is estimated that approximately 40% of patients with food allergies report at least one food allergy-related emergency department in their lifetime. Reactions, even from minimal exposures, can be life-threatening.

Oral immunotherapy (OIT) has been the best researched therapeutic approach for treating FA over the last decade, with clinical trials investigating its efficacy, safety, and ability to improve participants' quality of life (QoL). A number of studies and meta-analyses have shown that OIT treatment is effective in raising the threshold of reactivity to peanuts and other foods in addition to producing a measurable serum immune response to such therapy. Although OIT-related adverse events (AEs) are common during treatment, serious reactions are rare. In fact, while the majority of patients experience AEs related to dosing, most continue daily dosing in hopes of achieving protection against the culprit food. Moreover, the majority of participants report improvement of QoL after OIT and are positive about undergoing OIT. These results show patients’ commitment to OIT and their optimism regarding the benefits of treatment. As a first step in therapeutic options to protect from reactions to unintentional ingestion of allergenic foods, and importantly, to address the many psychosocial aspects of living with FA, OIT shows promise. Future research will focus on identifying optimal OIT regimens that maintain protection after therapy and allow for regular food consumption without allergic symptoms. Education and informed shared decision making between patients and providers are essential in optimizing current therapy regimens.

[Allergic immunotherapy in children and adolescents]

L’immunothérapie spécifique allergénique nécessite l’administration répétée d’allergènes dans le but de provoquer une tolérance clinique et immunologique. C’est la seule thérapeutique à visée étiologique qui permet de modifier l’évolution de la maladie en assurant une rémission après l’interruption de la procédure. La prévention de nouvelles sensibilisations par l’immunothérapie reste discutée. Nous envisagerons dans cette revue les principaux mécanismes immunologiques et les indications de l’immunothérapie chez l’enfant et l’adolescent.

Food allergy oral immunotherapy

Food allergy oral immunotherapy (OIT) has demonstrated efficacy in promoting clinically relevant immunomodulation that leads to desensitization (reduced reactivity while on OIT) in the majority of treated individuals; however, sustained unresponsiveness after OIT cessation for a specified interval has only been observed in a subset. The potential therapeutic benefits of OIT must be balanced with the risk for adverse events. These adverse events may range from self-limited or easily treated oropharyngeal, respiratory, or gastrointestinal symptoms to persistent abdominal symptoms that lead to cessation of therapy and to anaphylaxis. To date, the majority of studies have evaluated single-allergen OIT approaches; however, multi-allergen OIT has demonstrated favorable safety and efficacy outcomes, and is the subject of ongoing investigation. Recent U.S. Food and Drug Administration approval of the first licensed OIT product for peanut allergy challenges the long-standing paradigm of dietary food avoidance as the sole option for individuals with food allergy. Yet, the limitations of this "first-generation" treatment support the need for continued research and development of next-generation therapies to improve efficacy, minimize risk, and allow for broad applicability to both individuals with single-food allergy and those with multifood allergies. Optimizing future therapies will require developing novel approaches that maximize both efficacy and safety and/or tolerability outcomes, potentially through the combination with biologic therapies or adjuvants. Shared decision-making among patients, physicians, and parents and/or caregivers is critical to select optimal candidates for treatment with OIT by balancing the potential therapeutic benefit and possible risk reduction with a realistic consideration of OIT treatment burden and the risk of treatment-related adverse events.

Oral food challenges

Oral food challenge (OFC) is a procedure that is conducted most commonly by allergist/immunologists in their office or in food allergy centers to confirm a food allergy or to confirm tolerance to the food. The procedure as conducted in clinical practice is mostly open food challenge and, in research, a double-blind, placebo controlled food challenge. OFC has associated risks that can be minimized by having the challenges conducted by trained personnel who are prepared to treat allergic reactions and who have rescue medications available. However, OFCs have tremendous benefits to the patients and their families, including the potential to determine that a food is no longer an allergen and can be introduced into the diet. Even OFCs that result in clinical reactions have the benefit of confirming the food allergy and demonstrating the therapeutic effect of the rescue medications. The study of the outcomes of OFC has shed light on food allergy reactions and characteristics of the patients with food allergy as well as on the value of other diagnostic tests compared with OFC. OFCs have helped establish food allergy thresholds, confirm that subjects enrolled in research studies have the allergy, and demonstrate the response to the therapies tested in terms of ameliorating the allergic response or raising the reaction threshold. OFCs have also been used to promote the recent guidelines for the prevention of peanut allergy by identifying the infants at risk for peanut allergy but who are not allergic yet.