Long-term sublingual immunotherapy for peanut allergy in children: Clinical and immunologic evidence of desensitization

Targeting inhibitory Siglec-3 to suppress IgE-mediated human basophil degranulation

BACKGROUND

Sialic acid-binding immunoglobulin-like lectin-3 (Siglec-3 [CD33]) is a major Siglec expressed on human mast cells and basophils; engagement of CD33 leads to inhibition of cellular signaling via immunoreceptor tyrosine-based inhibitory motifs.

OBJECTIVE

We sought to inhibit human basophil degranulation by simultaneously recruiting inhibitory CD33 to the IgE-FcεRI complex by using monoclonal anti-IgE directly conjugated to CD33 ligand (CD33L).

METHODS

Direct and indirect basophil activation tests (BATs) were used to assess both antigen-specific (peanut) and antigen-nonspecific (polyclonal anti-IgE) stimulation. Whole blood from donors with allergy was used for direct BAT, whereas blood from donors with nonfood allergy was passively sensitized with plasma from donors with peanut allergy in the indirect BAT. Blood was incubated with anti-IgE-CD33L or controls for 1 hour or overnight and then stimulated with peanut, polyclonal anti-IgE, or N-formylmethionyl-leucyl-phenylalanine for 30 minutes. Degranulation was determined by measuring CD63 expression on the basophil surface by flow cytometry.

RESULTS

Incubation for 1 hour with anti-IgE-CD33L significantly reduced basophil degranulation after both allergen-induced (peanut) and polyclonal anti-IgE stimulation, with further suppression after overnight incubation with anti-IgE-CD33L. As expected, anti-IgE-CD33L did not block basophil degranulation due to N-formylmethionyl-leucyl-phenylalanine, providing evidence that this inhibition is IgE pathway-specific. Finally, CD33L is necessary for this suppression, as monoclonal anti-IgE without CD33L was unable to reduce basophil degranulation.

CONCLUSIONS

Pretreating human basophils with anti-IgE-CD33L significantly suppressed basophil degranulation through the IgE-FcεRI complex. The ability to abrogate IgE-mediated basophil degranulation is of particular interest, as treatment with anti-IgE-CD33L before antigen exposure could have broad implications for the treatment of food, drug, and environmental allergies.

Recent advances in food allergen immunotherapy

Food allergies can pose significant risks and profoundly impact the quality of life of children and their families, making them a major public health concern. Allergen avoidance has been the traditional mainstay of treatment; however, recent research has focused on various approaches to food allergen immunotherapy. This review summarizes the recent advancements in oral, sublingual, and epicutaneous immunotherapies, highlighting their respective advantages and disadvantages. The ultimate goal of food allergen immunotherapy is to maximize efficacy while minimizing risks, leading to the exploration of strategies such as low-dose immunotherapy and the use of biologics. When selecting candidates for immunotherapy among patients with food allergies, factors such as allergen characteristics, the likelihood of natural resolution, age, symptom severity, and impact on quality of life require consideration, and an individualized approach should be adopted to determine the most suitable treatment method.

Food Sublingual Immunotherapy: Safety and Simplicity of a Real Food Updosing Protocol

BACKGROUND

Sublingual immunotherapy (SLIT) using food extracts is safe and effective in desensitizing patients with food allergy, yet not often used in clinical practice.

OBJECTIVES

To propose a cost-effective, expedited SLIT protocol using real food.

METHODS

Patients with food allergy aged 5 to 50 years (median, 11 years) initiated food SLIT in a single-clinic setting. The daily maintenance dose was 4 to 11 mg protein in 0.1 to 0.5 mL volume, depending on the food. Some foods were available in liquid form at the local grocery (milk, egg white liquid, and cashew/walnut/sunflower/hazelnut milk), whereas others were prepared in the office using flour and 50% glycerin saline (peanut/sesame/wheat). The first cohort of 20 patients began dosing at a 1:1000 dilution, the next 30 patients at 1:100 dilution. An exercise challenge was performed in a subset of patients on maintenance dosing to evaluate the need for a predose or postdose rest period.

RESULTS

The 1:1000 and 1:100 cohorts both completed day 1 without adverse reactions beyond itchy mouth. There were no systemic reactions requiring epinephrine throughout the study period and 88% reached their maintenance dose. Skin testing of 6-month-old peanut flour solution was not diminished from fresh solution and similar to food extract. Exercise challenge test results in 12 patients were negative.

CONCLUSIONS

Allergen extract food SLIT as used in published trials has limitations of cost and multiple office visits. Inexpensive real food, at the same or slightly higher protein dose, was well tolerated in 4 updose visits, a minimum of a week apart. Unlike food oral immunotherapy, a predose or postdose rest period may not be necessary.

Sublingual immunotherapy for allergy to shrimp: the nine-year clinical experience of a Midwest Allergy-Immunology practice

BACKGROUND

Diet restrictions and fear of adverse reactions put a significant burden on the nutrition, growth and life style of children and adults with food allergies. While various disease-modifying options are pursued, there are so far no published clinical data on immunotherapy for crustaceans. The efficacy and safety of desensitization to crustaceans by means of sublingual immunotherapy is assessed for the first time in this study with a view of validating it as a clinical-practice modality.

METHODS

Charts of a Midwest Allergy-Immunology practice from the period January 2014-June 2023 were reviewed to identify patients with allergy to shrimp treated with sublingual immunotherapy and to retrospectively evaluate their responses to oral challenge.

RESULTS

Sixty-six patients were identified who had been treated by sublingual immunotherapy for either systemic or localized reactions to shrimp. Demographics and relevant comorbidities were consistent with those of the atopic population. Sublingual immunotherapy with serially diluted mixtures was initiated at 64-320 ng/dose and was gradually escalated to 0.5 mg/dose three times a day. The sublingual immunotherapy course ranged from 5 to 72 months (average: 51 months), following which, 18 patients underwent shrimp oral challenge. No systemic reactions occurred upon challenge; no patient required epinephrine. Tolerance of target dose equal to or exceeding 42 g shrimp was achieved in 11 patients (61%), seven of whom had originally presented with systemic reactions to crustaceans. Seven patients (38%) developed one or more of the following localized reactions: oral itching, nasal symptoms, localized perioral hives, localized hives at pressure points, nausea, vomiting, abdominal pain upon exposure to a cumulative dose of 39.2-148.2 g of shrimp during the 4 h of the challenge. Five of these patients had originally presented with systemic reactions to crustaceans. Five of the 7 patients who developed localized symptoms during the challenge were subsequently placed on routine exposure to 12-20 g shrimp every other day. Two patients continued sublingual immunotherapy but declined routine exposure to shrimp every other day because they had no intention to incorporate crustaceans to their routine diet. On repeat challenge 6-9 months after original challenge, all five patients who had routine exposure to 12-20 g shrimp every other day tolerated the procedure to target dose without any symptoms.

CONCLUSIONS

Desensitization to shrimp by sublingual immunotherapy appears to be safe and effective as shown in this study. Whether the immune modification induced by sublingual immunotherapy is permanent resulting in sustained tolerance, or the achieved degree of desensitization depends on regular exposure is not known; therefore, following challenge, regular consumption three-four times per week was recommended.

Safety and Effectiveness of Bypassing Oral Immunotherapy Buildup With an Initial Phase of Sublingual Immunotherapy for Higher-Risk Food Allergy

BACKGROUND

Because of its favorable safety, sublingual immunotherapy (SLIT) for food allergy has been proposed as an alternative treatment for those in whom oral immunotherapy (OIT) is of higher risk-older children, adolescents, adults, and those with a history of severe reactions. Although safe, SLIT has been shown to be less effective than OIT.

OBJECTIVE

To describe the safety of multifood SLIT in pediatric patients aged 4 to 18 years and the effectiveness of bypassing OIT buildup with an initial phase of SLIT.

METHODS

Patients aged 4 to 18 years were offered (multi)food SLIT. Patients built up to 2 mg protein SLIT maintenance over the course of 3 to 5 visits under nurse supervision. After 1 to 2 years of daily SLIT maintenance, patients were offered a low-dose oral food challenge (OFC) (cumulative dose, 300 mg protein) with the goal of bypassing OIT buildup.

RESULTS

Between summer 2020 and winter 2023, 188 patients were enrolled in SLIT (median age, 11 years). Four patients (2.10%) received epinephrine during buildup and went to the emergency department, but none experienced grade 4 (severe) reaction. A subset of 20 patients had 50 low-dose OFCs to 300 mg protein and 35 (70%) OFCs were successful, thereby bypassing OIT buildup.

CONCLUSIONS

In combination with very favorable safety of SLIT, with no life-threatening reactions and few reactions requiring epinephrine, we propose that an initial phase of SLIT to bypass supervised OIT buildup be considered for children in whom OIT is considered to be of higher risk.

Current state and advances in desensitization for peanut allergy in pediatric age

Peanut allergy affects about 1%-3% of the pediatric population in the world, with an important increase in the last decades. Nowadays, international guidelines recommend the early introduction of peanuts in the infant diet, with poor information about the quantity and the frequency of the intake. Allergen immunotherapy may represent the only therapeutic strategy able to modify the natural history of peanut allergy. In particular, oral immunotherapy showed the most promising results in terms of efficacy, but with significant rates of adverse reactions, mostly gastrointestinal. In 2020, the Food and Drug Administration and the European Medicines Agency approved Palforzia®, an oral drug for patients aged 4-17 years. Several studies are ongoing to improve the tolerability of oral immunotherapy and standardize the desensitization protocols. Sublingual immunotherapy permits to offer much lower doses than oral immunotherapy, but fewer adverse events are shown. Subcutaneous immunotherapy is associated with the greatest systemic adverse effects. Epicutaneous immunotherapy, for which Viaskin® patch was approved, has the highest safety profile. Innovative studies are evaluating the use of biological drugs, such as omalizumab or dupilumab, and probiotics, such as Lactobacillus rhamnosus, in monotherapy or associated with oral immunotherapy. Therapy for peanut allergy is constantly evolving, and new perspectives are ongoing to develop.

The Future of Food Allergy Management: Advancements in Therapies

PURPOSE OF REVIEW

To review current and future treatment options for IgE-mediated food allergy.

RECENT FINDINGS

Recent years have seen major developments in both allergen-specific and allergen-non-specific treatment options, with the first FDA-approved peanut oral immunotherapy (OIT) product becoming available in 2020. In addition to OIT, other immunotherapy modalities, biologics, adjunct therapies, and novel therapeutics are under investigation. Food allergy is a potentially life-threatening condition associated with a significant psychosocial impact. Numerous products and protocols are under investigation, with most studies focusing on OIT. A high rate of adverse events, need for frequent office visits, and cost remain challenges with OIT. Further work is needed to unify outcome measures, develop treatment protocols that minimize adverse events, establish demographic and clinical factors that influence candidate selection, and identify patient priorities.

New Approaches to Food Allergy Immunotherapy

Food allergy is an increasing public health problem in children and adults. In addition to the risk of potentially severe reactions, food allergy can have a significant burden on quality of life, nutrition, cost of living, and social activities. Traditionally, treatment has primarily included strict food allergen avoidance and use of emergency medications to treat an allergic reaction. However, in recent years, there have been significant strides in the advancement of food allergy treatment, including the approval of the first and only approved therapy (peanut oral immunotherapy) for food allergy in 2020. Clinical trials have primarily focused on food allergen immunotherapy (oral, epicutaneous, sublingual). Building off of a foundation of promising data supporting the efficacy of food oral immunotherapy and our greater understanding of the underlying mechanism of immunotherapy, newer approaches, including alternative routes of delivery, adjuncts to therapy, modified allergens, and utilization in younger patients, aim to provide safer and more effective treatment approaches to the millions of patients burdened by food allergy.

Mass Spectrometry Analysis on the Breakage of Allergens in High-Molecular-Mass Polymer of Roasted Peanuts

Peanut allergy is a prevalent and concerning food allergy. Roasting can introduce structural changes to peanut allergens, affecting their allergenicity, but the structure on the primary structure is unclear. Here, the breakage sites were identified by mass spectrometry and software tools, and structural changes were simulated by molecular dynamics and displayed by PyMOL software. Results revealed that the appearance frequencies of L, Q, F, and E were high at the N-terminal of the breakage site, while S and E were dominant at the C-terminal. In the conformational structure, breakage sites were found close to disulfide bonds and the Cupin domains of Ara h 1 and Ara h 3. The breakage of allergens destroyed linear epitopes and might change the conformation of epitopes, which could influence peanuts' potential allergenicity.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Food Allergen Immunotherapy in the Treatment of Patients with IgE-Mediated Food Allergy

The prevalence of allergic diseases, including food allergy, is increasing, especially in developed countries. Implementation of an elimination diet is not a sufficient therapeutic strategy in patients with food allergy, whose quality of life is significantly impaired. In recent years, new effective therapeutic strategies have been developed, such as the application of oral, sublingual, and epicutaneous immunotherapy. Oral immunotherapy is the most often applied strategy because of its effectiveness and ease of application, with an acceptable safety profile. The effectiveness of oral immunotherapy in patients with egg, cow's milk, and peanut allergy has been proven both in terms of raising of the threshold and the development of tolerance, and in some patients, the development of sustainable unresponsiveness. Although oral immunotherapy is an effective treatment for food allergy, several limitations, including a long duration and a significant rate of reported adverse events, reduces its success. Therefore, new therapeutic options, such as treatment with biologicals, either as combinations with food allergen immunotherapy or as monotherapy with the aim of improving the efficacy and safety of treatment, are being investigated.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Updates in food allergen immunotherapy

PURPOSE OF REVIEW

Food allergies are on the rise. Though allergen avoidance and management of acute reactions have been the backbone of therapy, complete avoidance and timely acute care is often not feasible. Food allergen immunotherapy (FAIT) is a novel and evolving treatment option intended to induce desensitization and potential sustained unresponsiveness (SU) to food allergens. This review addresses the methods, mechanisms, efficacy, and adverse effects of oral immunotherapy (OIT), sublingual immunotherapy (SLIT), and epicutaneous immunotherapy (EPIT) for food allergens in the published literature.

RECENT FINDINGS

Single FAIT has been most extensively studied in peanut, milk, and hen's egg allergic patients and has been successful in achieving desensitization in treated individuals through various modalities. Long-term data regarding SU is limited; however, current data suggests subsets of patients may be more likely to achieve SU compared to others. Other studies are actively assessing multifood AIT and novel FAIT protocols with adjunctive therapies.

SUMMARY

Food allergy constitutes a prevalent problem with far-reaching consequences. The emergence of FAIT may mitigate the burden of food allergy. Current evidence is promising for specific allergens and pediatric patient populations. Future studies are needed to further assess efficacy between different modalities of immunotherapy for food allergens across an age continuum.

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

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

The Value of Current Laboratory Tests in Diagnosing Food, Venom, and Drug Allergies

An accurate diagnosis of IgE-mediated allergies is necessary to inform risk management for severe allergic reactions including anaphylaxis for food, venom, and drug allergies. The most widely available laboratory test for allergy is serum-specific IgE testing, which is routinely used for food allergy and insect sting allergy. Testing for specific IgE is limited by high sensitivity and low specificity, resulting in concern regarding overdiagnosis. Testing of allergen components has led to improved diagnosis for some food and venom allergens. Additional options for laboratory tests, such as epitope analysis, basophil activation, and mast cell activation, are being investigated for their potential to optimize diagnosis and provide predictors for reaction severity and treatment response. In contrast, laboratory testing for drug allergy is more limited because to date, there are no well-validated commercial assays in the United States. Furthermore, it is important to diagnose delayed reactions to medications, because these also significantly affect decision-making regarding therapeutic options for infectious disorders. Reliable tests for both immediate and delayed drug hypersensitivity are much needed, because drug allergy labels can significantly limit treatment options for patients. Research in this area is emerging.

Optimal period for achieving sustained unresponsiveness in peanut oral immunotherapy

Background

Oral immunotherapy (OIT) can help children with persistent food allergies achieve sustained unresponsiveness (SU). However, the optimal therapeutic period for obtaining SU remains unclear.

Objective

We aimed to retrospectively investigate the association between the OIT treatment period and achievement of SU.

Methods

We enrolled patients who received OIT for peanut allergy between January 1, 2018 and December 31, 2022. OIT comprised the build-up phase, maintenance phase, complete avoidance, and an oral food challenge (OFC) for confirming SU. The peanut dose in the OFC was gradually increased to 3,000 mg (peanut protein: 795 mg), which was subsequently maintained for ≥5 months. SU was defined as a negative response to 795 mg of peanut protein after ≥2 weeks of complete avoidance. We evaluated the therapeutic OIT period for achieving SU using Kaplan-Meier analysis.

Results

Forty-eight patients underwent peanut OIT. The starting age at OIT initiation was 8 (interquartile range [IQR], 7-10) years. Forty-one (85%) patients had a history of anaphylaxis. The median specific immunoglobulin E concentration to peanut and Ara h 2 at OIT initiation was 85.3 (IQR, 33.7-100) and 57.6 (IQR, 21.9-100) UA/mL, respectively. The median observational period was 2.1 (IQR, 1.6-3.0) person-years (PY). Thirty-four (71%) patients achieved SU, with the rate of SU achievement gradually increasing with the therapeutic period. The median period until SU achievement was 2.1 (95% confidence interval, 1.6-2.5) PY. The rate of SU achievement slowed down after 2.7 PY.

Conclusion

OIT for at least 2.7 PY can increase the rate of SU achievement. The protocol No. 3107.

Immune response evolution in peanut epicutaneous immunotherapy for peanut-allergic children

BACKGROUND

Epicutaneous immunotherapy with investigational Viaskin™ Peanut 250 μg (DBV712) has demonstrated statistically superior desensitization versus placebo in peanut-allergic children in clinical trials. It is unclear whether serologic biomarkers predict response.

METHODS

Serum-specific IgG4 and IgE (whole peanut and components) from subjects enrolled in the phase 3 Efficacy and Safety of Viaskin Peanut in Children With IgE-Mediated Peanut Allergy study were examined by exploratory univariate and multivariate analyses to determine trajectories and predictors of treatment response, based upon peanut protein eliciting dose (ED) at Month (M) 12 double-blind placebo-controlled food challenge.

RESULTS

Among Viaskin Peanut-treated subjects, peanut sIgG4 significantly increased from baseline through M12 and peanut sIgE peaked at M3 and fell below baseline by M12, with sIgG4 and sIgE peanut components mirroring these trajectories. Placebo subjects had no significant changes. By univariate analysis, M12 peanut sIgG4/sIgE was higher in treatment responders (p < 0.001) and had highest area under the curve (AUC) for predicting ED ≥300 mg and ≥1000 mg (AUC 69.5% and 69.9%, respectively). M12 peanut sIgG4/sIgE >20.1 predicted M12 ED ≥300 mg (80% positive predictive value). The best performing component was Ara h 1 sIgE <15.7 kUA /L (AUC 66.5%). A multivariate model combining Ara h 1 and peanut sIgG4/sIgE had an AUC of 68.2% (ED ≥300 mg) and 67.8% (ED ≥1000 mg).

CONCLUSIONS

Peanut sIgG4 rise most clearly differentiated Viaskin Peanut versus placebo subjects. sIgG4/sIgE ratios >20.1 and the combination of Ara h 1 and peanut sIgG4/sIgE had moderate ability to predict treatment response and could potentially be useful for clinical monitoring. Additional data are needed to confirm these relationships.

An update on recent developments and highlights in food allergy

While both the incidence and general awareness of food allergies is increasing, the variety and clinical availability of therapeutics remain limited. Therefore, investigations into the potential factors contributing to the development of food allergy (FA) and the mechanisms of natural tolerance or induced desensitization are required. In addition, a detailed understanding of the pathophysiology of food allergies is needed to generate compelling, enduring, and safe treatment options. New findings regarding the contribution of barrier function, the effect of emollient interventions, mechanisms of allergen recognition, and the contributions of specific immune cell subsets through rodent models and human clinical studies provide novel insights. With the first approved treatment for peanut allergy, the clinical management of FA is evolving toward less intensive, alternative approaches involving fixed doses, lower maintenance dose targets, coadministration of biologicals, adjuvants, and tolerance-inducing formulations. The ultimate goal is to improve immunotherapy and develop precision-based medicine via risk phenotyping allowing optimal treatment for each food-allergic patient.

A case of food and aeroallergen sublingual immunotherapy inducing eosinophilic esophagitis

Eosinophilic esophagitis (EoE) has been reported secondary to aeroallergen sublingual immunotherapy (SLIT) and food allergen oral immunotherapy. Gastrointestinal symptoms with food allergen SLIT are uncommon, with no prior reports of cases of food allergen SLIT inducing EoE. Here we report a patient who developed EoE secondary to food and aeroallergen SLIT therapy that resolved with SLIT cessation.

Update on clinical research for food allergy treatment

The incidence of IgE-mediated food allergy (FA) has continued to increase over the years which places substantial burden on patient health and quality of life. With no cure for this disease, the mainstay of management has been allergen avoidance. However, there have been advancements in FA treatment in recent years with multiple clinical trials utilizing novel and innovative therapeutic strategies. A landmark event came in 2020 with the first drug approval for food allergy with the approval of a product for peanut oral immunotherapy. In addition to oral immunotherapy, different delivery systems of immunotherapy (SLIT, EPIT) are being studied in addition to probiotics, biologic agents - used as monotherapy and as an adjunct, and modified allergens has taken place with the hope to further enhance existing therapeutic options. The hope through these continued developments is for therapies to emerge that will provide a more comprehensive benefit to this patient population.

The future of food allergy: Challenging existing paradigms of clinical practice

The field of food allergy has seen tremendous change over the past 5-10 years with seminal studies redefining our approach to prevention and management and novel testing modalities in the horizon. Early introduction of allergenic foods is now recommended, challenging the previous paradigm of restrictive avoidance. The management of food allergy has shifted from a passive avoidance approach to active interventions that aim to provide protection from accidental exposures, decrease allergic reaction severity and improve the quality of life of food-allergic patients and their families. Additionally, novel diagnostic tools are making their way into clinical practice with the goal to reduce the need for food challenges and assist physicians in the-often complex-diagnostic process. With all the new developments and available choices for diagnosis, prevention and therapy, shared decision-making has become a key part of medical consultation, enabling patients to make the right choice for them, based on their values and preferences. Communication with patients has also become more complex over time, as patients are seeking advice online and through social media, but the information found online may be outdated, incorrect, or lacking in context. The role of the allergist has evolved to embrace all the above exciting developments and provide patients with the optimal care that fits their needs. In this review, we discuss recent developments as well as the evolution of the field of food allergy in the next decade.

Jak out of the box: Targeting Bruton's tyrosine kinase, sialic acid-binding immunoglobulin-like lectin-8, and Janus kinase 1 in food allergy

There has been rapid growth in the field of immunoglobulin E-mediated food allergy therapeutics, with 1 US Food and Drug Administration-approved therapy in 2020 and several others in various stages of investigation. Oral immunotherapy is the approach with the longest track record of study and provides desensitization for most individuals undertaking the therapy. However, the therapy must be maintained for continued clinical protection, and adverse effects of the therapy are frequent. There is a need to improve allergen immunotherapy safety and durability and to provide a treatment that can target multiple food allergies. In this review, we discuss novel adjunct therapies that may improve safety, such as omalizumab, Bruton's tyrosine kinase inhibitors, and agonists of sialic acid-binding immunoglobulin-like lectin-8, which suppress hypersensitivity responses. We also discuss approaches that may improve magnitude or durability of the treatment response, such as dupilumab and Janus kinase 1 inhibitors.

Abatacept to induce remission of peanut allergy during oral immunotherapy (ATARI): protocol for a phase 2a randomized controlled trial

Context

While oral immunotherapy (OIT) has been shown to promote the remission of mild peanut allergy in young children, there is still an unmet need for a disease-modifying intervention for older patients and those with severe diseases. In mice models, abatacept, a cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) immunoglobulin fusion protein, has been shown to promote immune tolerance to food when used as an adjuvant to allergen immunotherapy. The goal of this study is to explore the potential efficacy of abatacept in promoting immune tolerance to food allergens during OIT in humans.

Methods

In this phase 2a proof-of-concept study (NCT04872218), 14 peanut-allergic participants aged from 14 to 55 years will be randomized at a 1:1 ratio to abatacept vs. placebo for the first 24 weeks of a peanut OIT treatment (target maintenance dose of 300 mg peanut protein). The primary outcome will be the suppression of the OIT-induced surge in peanut-specific IgE/total IgE at 24 weeks, relative to the baseline. Sustained unresponsiveness will be assessed as a secondary outcome starting at 36 weeks by observing incremental periods of peanut avoidance followed by oral food challenges.

Discussion

This is the first study assessing the use of abatacept as an adjuvant to allergen immunotherapy in humans. As observed in preclinical studies, the ability of abatacept to modulate the peanut-specific immune response during OIT will serve as a proxy outcome for the development of clinical tolerance, given the small sample size. The study will also test a new patient-oriented approach to sustained tolerance testing in randomized controlled trials.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

EAACI Molecular Allergology User's Guide 2.0

Since the discovery of immunoglobulin E (IgE) as a mediator of allergic diseases in 1967, our knowledge about the immunological mechanisms of IgE-mediated allergies has remarkably increased. In addition to understanding the immune response and clinical symptoms, allergy diagnosis and management depend strongly on the precise identification of the elicitors of the IgE-mediated allergic reaction. In the past four decades, innovations in bioscience and technology have facilitated the identification and production of well-defined, highly pure molecules for component-resolved diagnosis (CRD), allowing a personalized diagnosis and management of the allergic disease for individual patients. The first edition of the "EAACI Molecular Allergology User's Guide" (MAUG) in 2016 rapidly became a key reference for clinicians, scientists, and interested readers with a background in allergology, immunology, biology, and medicine. Nevertheless, the field of molecular allergology is moving fast, and after 6 years, a new EAACI Taskforce was established to provide an updated document. The Molecular Allergology User's Guide 2.0 summarizes state-of-the-art information on allergen molecules, their clinical relevance, and their application in diagnostic algorithms for clinical practice. It is designed for both, clinicians and scientists, guiding health care professionals through the overwhelming list of different allergen molecules available for testing. Further, it provides diagnostic algorithms on the clinical relevance of allergenic molecules and gives an overview of their biology, the basic mechanisms of test formats, and the application of tests to measure allergen exposure.

Current and future treatments for peanut allergy

Peanut allergy (PA) is a common, burdensome childhood disease that in most patients continues into adulthood and has historically been untreatable. However, peanut oral immunotherapy (POIT) is increasingly being incorporated into allergy practices, using both the first FDA-approved product, PTAH (previously AR101; Palforzia™, Aimmune Therapeutics), as well as store-bought peanut products. POIT in preschoolers continues to gain more acceptance as evidence accrues that it is a safe and feasible approach that may have distinct advantages. There are many new therapeutic interventions currently under study with a variety of different approaches and potential mechanisms. With respect to other forms of immunotherapy, none are currently approved, but the epicutaneous approach is the most well-studied and others are being actively investigated, including sublingual, subcutaneous, and intralymphatic. Biologics are gaining evidence both as adjunctive treatments to POIT and as monotherapy. Omalizumab is the most widely studied biologic for PA but others also have potential. Looking ahead to a future therapeutic landscape of choice, allergists will need to understand each patient's goal of treatment through shared decision-making and fully evaluate the risks, benefits, and alternatives of each new therapy.

Immunology of allergen immunotherapy

Allergen immunotherapy (AIT) is the only disease-modifying therapy for allergic disease. Through repeated inoculations of low doses of allergen-either as whole proteins or peptides-patients can achieve a homeostatic balance between inflammatory effectors induced and/or associated with allergen contact, and mediators of immunologic non-responsiveness, potentially leading to sustained clinical improvements. AIT for airborne/respiratory tract allergens and insect venoms have traditionally been supplied subcutaneously, but other routes and modalities of administration can also be effective. Despite differences of allergen administration, there are some similarities of immunologic responses across platforms, with a general theme involving the restructuring and polarization of adaptive and innate immune effector cells. Here we review the immunology of AIT across various delivery platforms, including subcutaneous, sublingual, epicutaneous, intradermal, and intralymphatic approaches, emphasizing shared mechanisms associated with achieving immunologic non-responsiveness to allergen.

Food allergy, mechanisms, diagnosis and treatment: Innovation through a multi-targeted approach

The incidence of food allergy (FA) has continued to rise over the last several decades, posing significant burdens on health and quality of life. Significant strides into the advancement of FA diagnosis, prevention, and treatment have been made in recent years. In an effort to lower reliance on resource-intensive food challenges, the field has continued work toward the development of highly sensitive and specific assays capable of high-throughput analysis to assist in the diagnosis FA. In looking toward early infancy as a critical period in the development of allergy or acquisition of tolerance, evidence has increasingly suggested that early intervention via the early introduction of food allergens and maintenance of skin barrier function may decrease the risk of FA. As such, large-scale investigations are underway evaluating infant feeding and the impact of emollient and steroid use in infants with dry skin for the prevention of allergy. On the other end of the spectrum, the past few years have been witness to an explosive increase in clinical trials of novel and innovative therapeutic strategies aimed at the treatment of FA in those whom the disease has already manifested. A milestone in the field, 2020 marked the approval of the first drug, oral peanut allergen, for the indication of peanut allergy. With a foundation of promising data supporting the safety and efficacy of single- and multi-allergen oral immunotherapy, current efforts have turned toward the use of probiotics, biologic agents, and modified allergens to optimize and improve upon existing paradigms. Through these advancements, the field hopes to gain footing in the ongoing battle against FA.

Food allergy: History, definitions and treatment approaches

Allergen-specific immunotherapy for the treatment of immunoglobulin E mediated food allergies, specifically oral, epicutaneous, and sublingual immunotherapies, are promising options that may provide an alternative to strict avoidance of the dietary allergen. Of these potential therapies, oral immunotherapy is the furthest along in development, with strong evidence of efficacy in clinical trials, and has achieved regulatory approval. Nevertheless, oral immunotherapy may not be a suitable therapy for some patients due to the risk of adverse effects. In contrast to oral immunotherapy, epicutaneous and sublingual immunotherapies have demonstrated modest efficacy in clinical trials, with a favorable adverse effect profile, which suggests that these therapies may be possible contenders to oral immunotherapy in certain clinical situations. Familiarity with the various treatment approaches is vital for guiding patients and families as more therapeutic modalities become available for use outside of the research setting.

Pediatric sublingual allergen immunotherapy

Sublingual immunotherapy (SLIT) offers an important therapeutic modality in the management of children with respiratory allergies. Along with subcutaneous immunotherapy, these modalities are the only selections that have shown not merely relief of symptoms but also disease-modifying activity. SLIT can be given as either a dissolvable tablet (SLIT-T) or liquid drops (SLIT-D). In studies that examined the efficacy and safety in allergic rhinitis and asthma, SLIT-T and SLIT-D both show efficacy in reducing symptoms and the need for medication, although it seems that SLIT-T may show a better response. Almost all SLIT-D efficacy studies are with single allergens. There are virtually no data on the efficacy of mixing unrelated allergens in the same prescription. Both SLIT-T and SLIT-D treatments are safe, with the most common adverse effects being local ones, such as oral pruritus and mouth irritation, which tend to be mild and short lived. Studies that assess the role of SLIT in the prevention of new sensitizations and asthma in the pediatric population are insufficient and of mixed results; therefore, no conclusions can be made. In the treatment of other pediatric conditions, such as food allergy and atopic dermatitis, there are few studies that assessed if, and the degree of, the benefit with SLIT. In determining if SLIT should be prescribed for the pediatric patient, there is a need for shared decision-making to allow the older child and parents or caregivers to understand the pros and cons, and the costs of all the options and relate their values and preferences to the physician.

Sublingual immunotherapy as an option for effective food allergy treatment

Food allergy sublingual immunotherapy (SLIT) has demonstrated efficacy in inducing desensitization with lower rates of systemic adverse effects than oral immunotherapy (OIT). Long-term SLIT has been shown to induce sustained unresponsiveness, and there is evidence that high-dose SLIT protocols can achieve tolerance that approximates that of OIT. However, the cost of allergenic extract may make long-term, high-dose SLIT prohibitive. Consequently, some allergists have used food allergy SLIT as a temporary bridge to OIT. Other allergists have developed SLIT protocols by using suspensions prepared from whole foods instead of commercially available extracts. Because long-term maintenance dosing regimens for food allergy SLIT have not been standardized, studies are needed to determine the minimum effective doses and duration of food allergy SLIT for various foods. Clarity on these questions may open the door to establishing food allergy SLIT as a viable treatment option.

Optimized Extraction of cAMP From Jujube by Ultra-High Pressure Technology and the Anti-allergic Effect for Peanut Allergy Mouse

Jujube contains abundant cyclic adenosine monophosphate (cAMP). In contrast, the extraction technology of cAMP from jujube is still to be explored. In this study, the ultra-high pressure extraction (UHPE) conditions for obtaining the maximum cAMP yield from jujube were optimized. Orthogonal array design (OAD) was applied to evaluate the effects of three variables (pressure, pressure-holding time, and liquid-to-solid ratio) by UHPE on cAMP yield. The results showed that the optimal cAMP yield (1223.2 μg/g) was derived at 300 MPa, 20 min duration, and a liquid-to-solid ratio of 2.5 ml/g. In addition, as an important functional ingredient in jujube, cAMP has potential anti-allergic effect. To develop the functional characteristics of jujube, the effect of cAMP was characterized in vivo with the Balb/c mouse model of peanut allergy, which was established by subcutaneous injection of crude peanut protein extract (PN). The results showed that treatment with cAMP in PN-sensitized mice suppressed the lesions in jejunal tissues and allergic symptoms and restored spleen index. Meanwhile, cAMP treatment reduced serum levels of specific immunoglobulin E (IgE), histamine, as well as interleukin-4 (IL-4) and stimulated the secretion of tumor necrosis factor-α (TNF-α), whereas the serum levels of interleukin-10 (IL-10) were not affected. Our results suggested that cAMP has an anti-allergic effect in PN-sensitized mice.

Oral desensitization therapy for peanut allergy induces dynamic changes in peanut-specific immune responses

BACKGROUND

The PALISADE study, an international, phase 3 trial of peanut oral immunotherapy (POIT) with AR101, resulted in desensitization in children and adolescents who were highly allergic to peanut. An improved understanding of the immune mechanism induced in response to food allergen immunotherapy would enable more informed and effective therapeutic strategies. Our main purpose was to examine the immunological changes in blood samples from a subset of peanut-allergic individuals undergoing oral desensitization immunotherapy with AR101.

METHODS

Blood samples obtained as part of enrollment screening and at multiple time points during PALISADE study were used to assess basophil and CD4+ T-cell reactivity to peanut.

RESULTS

The absence of clinical reactivity to the entry double-blinded placebo-controlled peanut challenge (DBPCFC) was accompanied by a significantly lower basophil sensitivity and T-cell reactivity to peanut compared with DBPCFC reactors. At baseline, peanut-reactive TH2A cells were observed in many but not all peanut-allergic patients and their level in peripheral blood correlates with T-cell reactivity to peanut and with serum peanut-specific IgE and IgG4 levels. POIT reshaped circulating peanut-reactive T-cell responses in a subset-dependent manner. Changes in basophil and T-cell responses to peanut closely paralleled clinical benefits to AR101 therapy and resemble responses in those with lower clinical sensitivity to peanut. However, no difference in peanut-reactive Treg cell frequency was observed between groups.

CONCLUSION

Oral desensitization therapy with AR101 leads to decreased basophil sensitivity to peanut and reshapes peanut-reactive T effector cell responses supporting its potential as an immunomodulatory therapy.

The Road Toward Transformative Treatments for Food Allergy

A series of landmark studies have provided conclusive evidence that the early administration of food allergens dramatically prevents the emergence of food allergy. One of the greatest remaining challenges is whether patients with established food allergy can return to health. This challenge is particularly pressing in the case of allergies against peanut, tree nuts, fish, and shellfish which are lifelong in most patients and may elicit severe reactions. The standard of care for food allergy is allergen avoidance and the timely administration of epinephrine upon accidental exposure. Epinephrine, and other therapeutic options like antihistamines provide acute symptom relief but do not target the underlying pathology of the disease. In principle, any transformative treatment for established food allergy would require the restoration of a homeostatic immunological state. This may be attained through either an active, non-harmful immune response (immunological tolerance) or a lack of a harmful immune response (e.g., anergy), such that subsequent exposures to the allergen do not elicit a clinical reaction. Importantly, such a state must persist beyond the course of the treatment and exert its protective effects permanently. In this review, we will discuss the immunological mechanisms that maintain lifelong food allergies and are, consequently, those which must be dismantled or reprogrammed to instate a clinically non-reactive state. Arguably, the restoration of such a state in the context of an established food allergy would require a reprogramming of the immune response against a given food allergen. We will discuss existing and experimental therapeutic strategies to eliminate IgE reactivity and, lastly, will propose outstanding questions to pave the road to the development of novel, transformative therapeutics in food allergy.

Peanut oral immunotherapy – current trends in clinical trials

Immunotherapy for allergy has been practised for over 100 years. Low-dose repeated exposure to specific allergen extracts over several months to years can successfully induce clinical tolerance in patients with allergy to insect venoms, pollen, house dust mite and domestic animals. Different regimens and routes for immunotherapy include subcutaneous, sublingual, oral and intralymphatic. Food allergies have been difficult to treat in this way due to high anaphylactic potential and only recently the first immunotherapy for peanut allergy has received regulatory approval. Several clinical trials have indicated high efficacy in desensitisation of peanut-allergic individuals using oral immunotherapy, which allows for safer administration of relatively high allergen concentrations. Still, the risk of adverse events including serious allergic reactions and high anxiety levels for patients remains, demonstrating the need for further optimisation of treatment protocols. Here we discuss the design and outcomes of recent clinical trials with traditional oral immunotherapy, and consider alternative protocols and formulations for safer and more effective oral treatment strategies for peanut allergy.

Oral Immunotherapy for Children with Cow's Milk Allergy

Cow's milk allergy (CMA) is one of the most common IgE-dependent food allergies in children. Some children develop severe and persistent CMA, with near-fatal reactions after exposure to trace amounts of cow's milk (CM). Because milk and dairy products are included in various processed food products, it is difficult to completely remove milk, which negatively affects the quality of life of children with CMA. Oral immunotherapy (OIT) can alleviate food allergen-induced anaphylaxis under continuous ingestion of a little of the causative food. Children with severe CMA may benefit from OIT, but the treatment requires a long time and poses a risk of anaphylaxis. Moreover, in recent years, new therapies, including omalizumab, sublingual immunotherapy, and epicutaneous immunotherapy, have played the role of optional OIT. In this review, we present the current methods of and other attempts at OIT, and discuss OIT for safely treating CMA.

Basophil activation test in food allergy: is it ready for real-time?

PURPOSE OF REVIEW

Utilization of basophil activation in the diagnosis and monitoring of food allergy has gained increasing recognition. An ex-vivo functional assay, basophil activation reflects clinical reactivity, thereby providing clinically relevant insights. Moreover, as a biomarker of reactivity and tolerance, basophil activation testing (BAT) may provide a useful tool for management of food allergies. Despite its utility, significant limitations of BAT have prevented widespread use. Addressing these limitations will increase the future application and adoption of BAT in food allergy.

RECENT FINDINGS

A number of clinical trials in the past few years have demonstrated the use of BAT in the diagnosis and treatment of food allergy. Specifically, BAT has been found to be a biomarker of tolerance.

SUMMARY

Basophil activation testing is an effective biomarker for diagnosis and monitoring of food allergy.

From Allergen Molecules to Molecular Immunotherapy of Nut Allergy: A Hard Nut to Crack

Peanuts and tree nuts are two of the most common elicitors of immunoglobulin E (IgE)-mediated food allergy. Nut allergy is frequently associated with systemic reactions and can lead to potentially life-threatening respiratory and circulatory symptoms. Furthermore, nut allergy usually persists throughout life. Whether sensitized patients exhibit severe and life-threatening reactions (e.g., anaphylaxis), mild and/or local reactions (e.g., pollen-food allergy syndrome) or no relevant symptoms depends much on IgE recognition of digestion-resistant class I food allergens, IgE cross-reactivity of class II food allergens with respiratory allergens and clinically not relevant plant-derived carbohydrate epitopes, respectively. Accordingly, molecular allergy diagnosis based on the measurement of allergen-specific IgE levels to allergen molecules provides important information in addition to provocation testing in the diagnosis of food allergy. Molecular allergy diagnosis helps identifying the genuinely sensitizing nuts, it determines IgE sensitization to class I and II food allergen molecules and hence provides a basis for personalized forms of treatment such as precise prescription of diet and allergen-specific immunotherapy (AIT). Currently available forms of nut-specific AIT are based only on allergen extracts, have been mainly developed for peanut but not for other nuts and, unlike AIT for respiratory allergies which utilize often subcutaneous administration, are given preferentially by the oral route. Here we review prevalence of allergy to peanut and tree nuts in different populations of the world, summarize knowledge regarding the involved nut allergen molecules and current AIT approaches for nut allergy. We argue that nut-specific AIT may benefit from molecular subcutaneous AIT (SCIT) approaches but identify also possible hurdles for such an approach and explain why molecular SCIT may be a hard nut to crack.

Clinical Manifestations of Pediatric Food Allergy: a Contemporary Review

Food allergies (FAs) are an emerging health care issue, and a "second wave of the allergy epidemic" was named. There are extensive data that documented the prevalence rate as high as approximately 10%. FAs are immunological adverse reactions, including IgE-mediated mechanisms, cell-mediated mechanisms, or mixed IgE- and cell-mediated mechanisms. A diagnosis of FA is made by specific symptoms encounter with food, detailed past history, sensitization tests, and oral food challenges (OFCs) if necessary. The component-resolved diagnostics (CRD) test can distinguish true or cross-reaction. "Minimal elimination" from the results of CRD and OFC could avoid unnecessary food restriction. Strict food limitation is harsh and stressful on patients and their families. Children with FAs experience a higher rate of post-traumatic stress symptoms (PTSS) and bullying than others. In the last 20 years, oral immunotherapy (OIT), sublingual immunotherapy (SLIT), and epicutaneous immunotherapy (EPIT) are treatment strategies. OIT and EPIT are the most two encouraging treatments for FA. This review aims to introduce FAs in diverse clinical disorders, new perspectives, and their practical implications in diagnosing and treating FA.

Novel Approaches in the Inhibition of IgE-Induced Mast Cell Reactivity in Food Allergy

Allergy is an IgE-dependent type-I hypersensitivity reaction that can lead to life-threatening systemic symptoms such as anaphylaxis. In the pathogenesis of the allergic response, the common upstream event is the binding of allergens to specific IgE, inducing cross-linking of the high-affinity FcεRI on mast cells, triggering cellular degranulation and the release of histamine, proteases, lipids mediators, cytokines and chemokines with inflammatory activity. A number of novel therapeutic options to curb mast cell activation are in the pipeline for the treatment of severe allergies. In addition to anti-IgE therapy and allergen-specific immunotherapy, monoclonal antibodies targeted against several key Th2/alarmin cytokines (i.e. IL-4Rα, IL-33, TSLP), active modification of allergen-specific IgE (i.e. inhibitory compounds, monoclonal antibodies, de-sialylation), engagement of inhibitory receptors on mast cells and allergen-specific adjuvant vaccines, are new promising options to inhibit the uncontrolled release of mast cell mediators upon allergen exposure. In this review, we critically discuss the novel approaches targeting mast cells limiting allergic responses and the immunological mechanisms involved, with special interest on food allergy treatment.

Precision medicine for cow's milk immunotherapy in clinical practice

PURPOSE OF REVIEW

Several novel immunotherapies have recently been reported for the treatment of cow's milk allergy (CMA). However, systematic methods for the selection of immunotherapy in clinical practice have not been investigated. In this review, we have provided suggestions for safe and effective immunotherapy for patients with CMA.

RECENT FINDINGS

Recent studies on cow's milk immunotherapy, using lower target doses, heated or baked cow's milk, combination treatment with adjuvants, or various routes of immunotherapy, included school-aged children with severe allergies, infants, and patients with mild CMA. These patients were administered various maintenance doses for various time periods. In the selection of immunotherapy, it would be useful to consider the patient's age and CMA severity at baseline: threshold dose, history of cow's milk anaphylaxis, and cow's milk-specific IgE levels.

SUMMARY

Considering the risks and benefits for patients with CMA, appropriate treatment should be selected based on the current evidence. Low-dose oral immunotherapy may be useful in clinical practice for school-aged children with severe CMA. Additional studies are needed to assess the indications for immunotherapy to select appropriate treatments in real-life settings.

Treatment Approaches to Food Allergy

IgE-mediated food allergies affect both children and adults and are associated with dramatic decreases in the quality of life. In the majority of cases, food allergens have to be avoided which may be difficult, particularly in patients who suffer from life-threatening symptoms following the ingestion of minimal doses of food allergens. Several novel therapeutic approaches have been studied during the recent past and are summarized in this review. Therapies with novel therapeutic monoclonal antibodies, innovative allergen-specific immunotherapies using subcutaneous, sublingual, or epicutaneous routes, and oral immunotherapies leading to increases of individual thresholds of tolerable foods upon their continuous ingestion showed promising results which may change future management strategies in moderate to severe food allergy.

Nanoparticles Displaying Allergen and Siglec-8 Ligands Suppress IgE-FcεRI-Mediated Anaphylaxis and Desensitize Mast Cells to Subsequent Antigen Challenge

Siglec-8 is an inhibitory receptor expressed on eosinophils and mast cells. In this study, we took advantage of a novel Siglec-8 transgenic mouse model to assess the impact of modulating IgE-dependent mast cell degranulation and anaphylaxis using a liposomal platform to display an allergen with or without a synthetic glycan ligand for Siglec-8 (Sig8L). The hypothesis is that recruitment of Siglec-8 to the IgE-FcεRI receptor complex will inhibit allergen-induced mast cell degranulation. Codisplay of both allergen and Sig8L on liposomes profoundly suppresses IgE-mediated degranulation of mouse bone marrow-derived mast cells or rat basophilic leukemia cells expressing Siglec-8. In contrast, liposomes displaying only Sig8L have no significant suppression of antigenic liposome-induced degranulation, demonstrating that the inhibitory activity by Siglec-8 occurs only when Ag and Sig8L are on the same particle. In mouse models of anaphylaxis, display of Sig8L on antigenic liposomes completely suppresses IgE-mediated anaphylaxis in transgenic mice with mast cells expressing Siglec-8 but has no protection in mice that do not express Siglec-8. Furthermore, mice protected from anaphylaxis remain desensitized to subsequent allergen challenge because of loss of Ag-specific IgE from the cell surface and accelerated clearance of IgE from the blood. Thus, although expression of human Siglec-8 on murine mast cells does not by itself modulate IgE-FcεRI-mediated cell activation, the enforced recruitment of Siglec-8 to the FcεRI receptor by Sig8L-decorated antigenic liposomes results in inhibition of degranulation and desensitization to subsequent Ag exposure.

Food Allergy from Infancy Through Adulthood

Food allergies are the result of immune responses that cause adverse reactions to foods. Immune responses to foods may produce a spectrum of symptoms and disorders, including acute allergic reactions and anaphylaxis, food protein-induced allergic proctocolitis, food protein-induced enterocolitis syndrome, food-dependent, exercise-induced anaphylaxis, and oral allergy syndrome (pollen-food allergy syndrome). Food-allergic responses also contribute to chronic inflammatory disorders such as eosinophilic esophagitis and atopic dermatitis. Although food allergy affects people from infancy through adulthood, there are allergic features that differ according to age (ie, presentation, triggers, and natural course) and have important implications for diagnosis, prognosis, and management. New food allergies can develop at any age, and we propose similarities in the etiology of de novo food allergy whether in infancy or adulthood. The approach to managing food allergy changes dramatically over the life course, and physicians and patients must respond accordingly to optimize care. Food allergy therapies are emerging, and the efficacy and safety of these interventions could differ by age group of those treated. In this review, we highlight interesting observations on the etiology and characteristics of food allergy presenting at different ages and discuss clinical management as it relates to life stage.

Regulatory Requirements for the Quality of Allergen Products for Allergen Immunotherapy of Food Allergy

Purpose of Review

Medicinal products for allergen immunotherapy (AIT) of food allergies have gained enormous momentum in recent years. With this new class of products entering marketing authorization procedures, compliance to regulatory requirements becomes a critical element. Here, an overview is provided on specific requirements and aspects concerning the quality control and manufacturing of these products.

Recent Findings

Recent developments in the field of AIT for food allergies are divers, including products for oral, epicutaneous, and subcutaneous application, most notably targeting egg, milk, and peanut allergy. As the source materials for food AIT product are typically produced for food consumption and not for medicinal purposes, unique challenges arise in the manufacturing processes and controls of these medicinal products. Individual approaches are needed to assure acceptable quality, including control of relevant quantitative and qualitative characteristics. Major characteristics for quality verification include determination of protein content, total allergenic activity, and major allergen content. The applied manufacturing processes need to be established such that relevant process parameters are kept within justified limits and consistency of produced batches is assured.

Summary

Allergen products for food AIT present specific challenges with respect to quality aspects that differentiate them from other commonly available AIT products. While established regulation is available and provides clear guidance for most aspects, other issues require consideration of new and individual settings relevant here. Consequently, as experience grows, respective amendments to currently available guidance may be needed.