Oral immunotherapy for treatment of egg allergy in children

One hundred and ten years of Allergen Immunotherapy: A journey from empiric observation to evidence

One hundred and ten years after Noon's first clinical report of the subcutaneous application of allergen extracts, allergen immunotherapy (AIT) has evolved as the most important pillar of the treatment of allergic patients. It is the only disease-modifying treatment option available and the evidence for its clinical efficacy and safety is broad and undisputed. Throughout recent decades, more insights into the underlying mechanisms, in particular the modulation of innate and adaptive immune responses, have been described. AIT is acknowledged by worldwide regulatory authorities, and following the regulatory guidelines for product development, AIT products are subject to a rigorous evaluation before obtaining market authorization. Knowledge and practice are anchored in international guidelines, such as the recently published series of the European Academy of Allergy and Clinical Immunology (EAACI). Innovative approaches continue to be further developed with the focus on clinical improvement by, for example, the usage of adjuvants, peptides, recombinants, modification of allergens, new routes of administration, and the concomitant use of biologicals. In addition, real-life data provide complementary and valuable information on the effectiveness and tolerability of this treatment option in the clinical routine. New mobile health technologies and big-data approaches will improve daily treatment convenience, adherence, and efficacy of AIT. However, the current coronavirus disease 2019 (COVID-19) pandemic has also had some implications for the feasibility and practicability of AIT. Taken together, AIT as the only disease-modifying therapy in allergic diseases has been broadly investigated over the past 110 years laying the path for innovations and further improvement.

Efficacy and safety of oral immunotherapy in children aged 1-3 years with peanut allergy (the Immune Tolerance Network IMPACT trial): a randomised placebo-controlled study

BACKGROUND

For young children with peanut allergy, dietary avoidance is the current standard of care. We aimed to assess whether peanut oral immunotherapy can induce desensitisation (an increased allergic reaction threshold while on therapy) or remission (a state of non-responsiveness after discontinuation of immunotherapy) in this population.

METHODS

We did a randomised, double-blind, placebo-controlled study in five US academic medical centres. Eligible participants were children aged 12 to younger than 48 months who were reactive to 500 mg or less of peanut protein during a double-blind, placebo-controlled food challenge (DBPCFC). Participants were randomly assigned by use of a computer, in a 2:1 allocation ratio, to receive peanut oral immunotherapy or placebo for 134 weeks (2000 mg peanut protein per day) followed by 26 weeks of avoidance, with participants and study staff and investigators masked to group treatment assignment. The primary outcome was desensitisation at the end of treatment (week 134), and remission after avoidance (week 160), as the key secondary outcome, were assessed by DBPCFC to 5000 mg in the intention-to-treat population. Safety and immunological parameters were assessed in the same population. This trial is registered on ClinicalTrials.gov, NCT03345160.

FINDINGS

Between Aug 13, 2013, and Oct 1, 2015, 146 children, with a median age of 39·3 months (IQR 30·8-44·7), were randomly assigned to receive peanut oral immunotherapy (96 participants) or placebo (50 participants). At week 134, 68 (71%, 95% CI 61-80) of 96 participants who received peanut oral immunotherapy compared with one (2%, 0·05-11) of 50 who received placebo met the primary outcome of desensitisation (risk difference [RD] 69%, 95% CI 59-79; p<0·0001). The median cumulative tolerated dose during the week 134 DBPCFC was 5005 mg (IQR 3755-5005) for peanut oral immunotherapy versus 5 mg (0-105) for placebo (p<0·0001). After avoidance, 20 (21%, 95% CI 13-30) of 96 participants receiving peanut oral immunotherapy compared with one (2%, 0·05-11) of 50 receiving placebo met remission criteria (RD 19%, 95% CI 10-28; p=0·0021). The median cumulative tolerated dose during the week 160 DBPCFC was 755 mg (IQR 0-2755) for peanut oral immunotherapy and 0 mg (0-55) for placebo (p<0·0001). A significant proportion of participants receiving peanut oral immunotherapy who passed the 5000 mg DBPCFC at week 134 could no longer tolerate 5000 mg at week 160 (p<0·001). The participant receiving placebo who was desensitised at week 134 also achieved remission at week 160. Compared with placebo, peanut oral immunotherapy decreased peanut-specific and Ara h2-specific IgE, skin prick test, and basophil activation, and increased peanut-specific and Ara h2-specific IgG4 at weeks 134 and 160. By use of multivariable regression analysis of participants receiving peanut oral immunotherapy, younger age and lower baseline peanut-specific IgE was predictive of remission. Most participants (98% with peanut oral immunotherapy vs 80% with placebo) had at least one oral immunotherapy dosing reaction, predominantly mild to moderate and occurring more frequently in participants receiving peanut oral immunotherapy. 35 oral immunotherapy dosing events with moderate symptoms were treated with epinephrine in 21 participants receiving peanut oral immunotherapy.

INTERPRETATION

In children with a peanut allergy, initiation of peanut oral immunotherapy before age 4 years was associated with an increase in both desensitisation and remission. Development of remission correlated with immunological biomarkers. The outcomes suggest a window of opportunity at a young age for intervention to induce remission of peanut allergy.

FUNDING

National Institute of Allergy and Infectious Disease, Immune Tolerance Network.

Mucosal Mast Cells as Key Effector Cells in Food Allergies

Mucosal mast cells (MMCs) localized in the intestinal mucosa play a key role in the development of IgE-mediated food allergies. Recent advances have revealed that MMCs are a distinctly different population from connective tissue mast cells localized in skin and other connective tissues. MMCs are inducible and transient cells that arise from bone marrow-derived mast cell progenitors, and their numbers increase rapidly during mucosal allergic inflammation. However, the mechanism of the dramatic expansion of MMCs and their cell functions are not well understood. Here, we review recent findings on the mechanisms of MMC differentiation and expansion, and we discuss the potential for the inducers of differentiation and expansion to serve as targets for food allergy therapy. In addition, we also discuss the mechanism by which oral immunotherapy, a promising treatment for food allergy patients, induces unresponsiveness to food allergens and the roles of MMCs in this process. Research focusing on MMCs should provide useful information for understanding the underlying mechanisms of food allergies in order to further advance the treatment of food allergies.

Oral Immunotherapy in Food Allergy: A Critical Pediatric Perspective

There is evidence that in children with persistent IgE-mediated food allergy (FA) to cow's milk, hen's egg, and peanut, oral allergen-specific immunotherapy (OIT) may increase the reaction threshold to the culprit food allergen(s). OIT may protect patients from the occurrence of severe reactions in case of accidental ingestion of the culprit food during treatment. Notwithstanding, many gaps are still unsolved, including safety issues, identification of predictive biomarkers, and post-desensitization efficacy. In this perspective, the use of omalizumab (Anti-IgE monoclonal antibody) has been proposed as an adjunctive treatment to OIT in order to reduce the risk of allergic reactions related to OIT. This review aims to summarize the current evidence and unmet needs on OIT in children with FA to enhance the development of longitudinal, prospective, and well-designed studies able to fill the current gaps soon.

Advances, Practical Implementation, and Unmet Needs Regarding Oral Immunotherapy for Food Allergy

Treatment of food allergy is a rapidly changing landscape, with arguably, the most significant advancement in recent years, the transition of oral immunotherapy (OIT) to clinical practice. As an innovation, OIT is a phase of rapidly increasing demand, particularly for some allergens such as peanut, egg, and milk, which have substantial evidence of efficacy. However, significant questions remain about how to best treat multiple food allergies and less common food allergies and how to optimize long-term safety and efficacy. This review summarizes the currently available resources for integrating food allergy OIT into clinical practice and focuses on the multiple remaining unmet needs such as providing an approach for OIT to food allergens for which there is no or limited evidence; practical issues related to food allergy treatment particularly when it is not going well; long-term outcomes and follow-up after OIT; and strategies to help meet the impending increase in demand.

Oral Immunotherapy in Children: Clinical Considerations and Practical Management

Oral immunotherapy (OIT) in pediatric patients provides an alternative option to the current standard of care in food allergy, which is allergen avoidance and reactive treatment. Because patients are exposed to one or more food allergens during treatment, OIT is associated with adverse events and can be a cumbersome process for children, their caregivers, and clinicians. However, there have been an overwhelming number of studies that show high efficacy in both single- and multi-allergen OIT, and that quality of life is greatly improved for both patients and their families after undergoing immunotherapy. This review discusses clinical considerations for OIT in pediatrics, including efficacy and safety, practical management, and future directions of treatment.

B cells and food allergy

PURPOSE OF REVIEW

B cells are known in food allergy pathogenesis for their production of IgE but their roles in the development of tolerance to foods are not well understood. Further understanding of B-cell biology in the context of food allergy is essential for the creation of effective prevention strategies and therapies.

RECENT FINDINGS

The majority of allergen-specific IgE in humans appears to arise from antigen-experienced B cells that have already undergone class switch recombination to other antibody isotypes, such as IgG1, and can also be produced by cells class switching to IgE locally in the gastrointestinal tract. Allergen-specific IgG4 can have protective effects in individuals and is associated with tolerance. Regulatory B cells, which can produce allergen-specific IgG4, are reduced in food-allergic individuals and may also be an important component of tolerance. Therapeutic approaches that block the generation and action of IgE and that enhance tolerizing immune responses are being evaluated for the treatment of food allergy.

SUMMARY

B cells play several roles in the development of food allergy versus tolerance. Their functions may translate into the care of food allergy as biomarkers or therapeutic targets and can be employed in other atopic diseases to better understand their pathogenesis and create new avenues for treatment.

Efficacy and Safety of Baked Milk Oral Immunotherapy in Children with Severe Milk Allergy: A Randomized, Double-blind, Placebo-controlled Phase 2 Trial

BACKGROUND

Cow's milk allergy is the most common food allergy in young children and has no current treatment. Oral immunotherapy studies to date have shown efficacy but high rates of adverse reactions.

OBJECTIVE

We sought to evaluate the safety and efficacy of baked milk oral immunotherapy (BMOIT) in baked milk allergic children.

METHODS

Participants (3-18 years) were randomized to receive BMOIT or placebo for 12 months. Efficacy was assessed by double-blind placebo-controlled food challenge after 12 months of treatment. Safety, quality of life, and mechanistic parameters were also evaluated.

RESULTS

11/15 (73%) of the BMOIT participants reached the primary endpoint, tolerating 4044 mg of baked milk protein after 12 months of OIT, compared to 0/15 (0%) on placebo. The median maximal tolerated dose (MTD) and median change from baseline was significantly higher in the BMOIT group compared to placebo (median MTD 4044mg vs 144mg; p=0.001; median change in MTD of 3900mg vs 0mg, p=0.0001). Dose-related reactions were common but >95% in both groups were mild. There was no significant change in CM- or beta lactoglobulin-IgE from baseline for either group. CM-sIgG4 did significantly increase and casein IgE decreased in the BMOIT group. For proxy-reported food allergy quality of life, there was a significant difference in the emotional impact domain only with more improving while on placebo compared BMOIT. The majority of children and adolescents in the BMOIT group directly reported improvement in at least one domain.

CONCLUSION

BMOIT was well tolerated and induced a substantial level of desensitization after 12 months of treatment.

COVID-19 vaccine-related presumed allergic reactions and second dose administration by using a two-step graded protocol

Background: Acute allergic reactions to messenger RNA (mRNA) vaccines are rare but may limit public health immunization efforts. Objectives: To characterize suspected allergic reactions to the first dose of coronavirus disease 2019 (COVID-19) mRNA vaccine and to assess the safety and utility of a two-step graded-dose protocol for the second dose of the Pfizer-BioNTech vaccine in patients with a history of low suspicion of anaphylaxis to their first dose. Methods: This was a retrospective evaluation of referrals to the allergy and immunology clinic for a presumed allergic reaction to the first dose of the COVID-19 mRNA vaccine (Pfizer-BioNTech or Moderna) between December 17, 2020, and February 28, 2021. Recommendations for the second dose and outcomes were evaluated by trained board-certified allergists. Results: Seventy-seven patients presented with a Pfizer-BioNTech reaction (56 [72.7%]) or with a Moderna reaction (21 [27.3%]). Most patients (69.7%) had symptom onset within 4 hours. Most commonly reported symptoms were cutaneous (51.9%), cardiovascular (48.1%), and respiratory (33.8%) symptoms. Recommendations included to proceed with the single dose (70.1%), two-step graded dose (19.5%), or deferral (10.4%). Twelve of 15 patients completed the second dose with a graded-dose protocol. Of these patients, five reported at least one or more similar symptoms as experienced with their first dose. Conclusion: Of the patients with presumed allergic reactions to their first dose of COVID-19 mRNA vaccine, most were able to safely receive the second dose. For those with a low suspicion of anaphylaxis, the two-step graded protocol with the Pfizer-BioNTech vaccine was well tolerated. A graded-dose protocol could be an effective strategy for second-dose vaccination in those who may otherwise defer the second dose.

Oral immunotherapy in children with a food allergy-Where do we stand? - Review

The number of hospitalisations due to an anaphylactic reaction to food is continuously increasing. Therefore, there is an urgent need to seek effective therapy. Currently, the only way to treat food allergies is to avoid allergens and to administer intramuscular adrenaline if an accidental allergen intake occurs. The only causal therapeutic strategy is specific oral immunotherapy. An increasing amount of data confirms this therapy's effectiveness and safety, but the results remain inconclusive due to the lack of long-term follow-up. In this state-of-the-art review, we briefly summarise the latest placebo-controlled randomised controlled trials on oral immunotherapy (OIT) to treat food allergy. During the paper's review, we asked the following questions: does the therapy permanently increase the amount of allergen consumed without symptoms? Does it significantly increase or decrease the occurrence of severe systemic reactions - requiring the administration of adrenaline or hospitalisation? Many authors describe outcomes such as an increase in the amount of allergen that can be safely ingested; however, significant clinical benefits such as decreased hospitalisations or anaphylaxis incidence are rarely included in the results. To date, there is no unified protocol of therapy, which makes comparisons between studies difficult because of significant differences in types, doses, and routes of administration of the allergen, timeline for up-dosing and maintenance, duration of the therapy, and primary outcomes of OIT.

Oral Immunotherapy for Food-Allergic Children: A Pro-Con Debate

The prevalence of food allergy has increased in recent years, especially in children. Allergen avoidance, and drugs in case of an allergic reaction, remains the standard of care in food allergy. Nevertheless, increasing attention has been given to the possibility to treat food allergy, through immunotherapy, particularly oral immunotherapy (OIT). Several OIT protocols and clinical trials have been published. Most of them focus on children allergic to milk, egg, or peanut, although recent studies developed protocols for other foods, such as wheat and different nuts. OIT efficacy in randomized controlled trials is usually evaluated as the possibility for patients to achieve desensitization through the consumption of an increasing amount of a food allergen, while the issue of a possible long-term sustained unresponsiveness has not been completely addressed. Here, we evaluated current pediatric OIT knowledge, focusing on the results of clinical trials and current guidelines. Specifically, we wanted to highlight what is known in terms of OIT efficacy and effectiveness, safety, and impact on quality of life. For each aspect, we reported the pros and the cons, inferable from published literature. In conclusion, even though many protocols, reviews and meta-analysis have been published on this topic, pediatric OIT remains a controversial therapy and no definitive generalized conclusion may be drawn so far. It should be an option provided by specialized teams, when both patients and their families are prone to adhere to the proposed protocol. Efficacy, long-term effectiveness, possible role of adjuvant therapies, risk of severe reactions including anaphylaxis or eosinophilic esophagitis, and impact on the quality of life of both children and caregivers are all aspects that should be discussed before starting OIT. Future studies are needed to provide firm clinical and scientific evidence, which should also consider patient reported outcomes.

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.

Intranasal delivery of allergen in a nanoemulsion adjuvant inhibits allergen-specific reactions in mouse models of allergic airway disease

BACKGROUND

Atopic diseases are an increasing problem that involve both immediate hypersensitivity reactions mediated by IgE and unique cellular inflammation. Many forms of specific immunotherapy involve the administration of allergen to suppress allergic immune responses but are focused on IgE-mediated reactions. In contrast, the effect of allergen-specific immunotherapy on allergic inflammation is complex, not entirely consistent and not well understood. We have previously demonstrated the ability of allergen administered in a nanoemulsion (NE) mucosal adjuvant to suppress IgE-mediated allergic responses and protect from allergen challenge in murine food allergy models. This activity was associated with decreases in allergen-specific IL-10 and reductions in allergic cytokines and increases in regulatory T cells.

OBJECTIVE

Here, we extend these studies to using 2 distinct models, the ovalbumin (OVA) and cockroach (CRA) models of allergic airway disease, which are based predominantly on allergic inflammation.

METHODS

Acute or chronic allergic airway disease was induced in mice using ovalbumin and cockroach allergen models. Mice received three therapeutic immunizations with allergen in NE, and reactivity to airway challenge was determined.

RESULTS

Therapeutic immunization with cockroach or OVA allergen in NE markedly reduced pathology after airway challenge. The 2 models demonstrated protection from allergen challenge-induced pathology that was associated with suppression of Th2-polarized immune responses in the lung. In addition, the reduction in ILC2 numbers in the lungs of allergic mice along with reduction in epithelial cell alarmins, IL-25 and IL-33, suggests an overall change in the lung immune environment induced by the NE immunization protocol.

CONCLUSIONS AND CLINICAL RELEVANCE

These results demonstrate that suppression of allergic airway inflammation and bronchial hyper-reactivity can be achieved using allergen-specific immunotherapy without significant reductions in allergen-specific IgE and suggest that ILC2 cells may be critical targets for this activity.

Combining Anti-IgE Monoclonal Antibodies and Oral Immunotherapy for the Treatment of Food Allergy

Immunoglobulin E (IgE)-mediated food allergy is a real public health problem worldwide. The prevalence of food allergy is particularly high in children. Patients with food allergy experience high morbidity with a change in quality of life due to the risk of severe anaphylaxis. Current treatment options are poor. Allergen avoidance is widely recommended but exposes patients to accidental ingestion. Oral immunotherapy is also used in patients with food allergies to the most common allergens. Oral immunotherapy consists of a daily administration of small, gradually increasing amounts of allergens to induce desensitisation. This procedure aims at inducing immune tolerance to the ingested food allergens. However, some patients experience adverse reactions and discontinue oral immunotherapy.Given that IgE plays a crucial role in food allergy and anti-IgE are effective in allergic asthma, the use of anti-IgE therapeutic monoclonal antibodies (mAbs) such as omalizumab has been assessed in food allergy patients. The use of omalizumab as a monotherapy in food allergy has not been extensively studied but looks promising. There is more published evidence regarding the effect of omalizumab and oral immunotherapy in food allergy. Given the promising results of oral immunotherapy regarding sustained tolerance in clinical trials and the potential capacity of omalizumab to reduce symptoms in case of accidental exposure, a strategy combining oral immunotherapy with omalizumab pre-treatment has been suggested as a safer option in patients with severe food allergy compared to isolated therapy. Omalizumab seems useful in ensuring safer administration of oral immunotherapy with the oral immunotherapy maintenance dose being reached more rapidly. Quality-of-life improvement is greater with oral immunotherapy + omalizumab compared to oral immunotherapy alone. Moreover, sustained unresponsiveness is achieved more frequently with omalizumab. Considering that precision medicine and personalised therapy are major goals for allergic diseases, predictive biomarkers are crucial in order to identify food allergy patients more likely to benefit from anti-IgE therapies.

Bringing the Next Generation of Food Allergy Diagnostics into the Clinic

Food allergy diagnosis has a massive impact on the lives of patients and their families. Despite recent developments with specific IgE to component allergens, a significant proportion of patients assessed for possible food allergy require oral food challenge to ensure an accurate diagnosis. More precise diagnostic methods are required to reduce the need for oral food challenges. Bead-based epitope assays and cellular tests, such as basophil activation and mast cell tests are the most novel and promising tests on the horizon. There is a pathway to pursue to enable their incorporation in clinical practice, including standardization, technical validation, clinical validation, external validation, overcoming practical and logistical issues, and regulatory approval. Valuable clinical application of these tests goes beyond diagnosis and includes risk assessment to identify allergic patients who are most sensitive and at risk for severe allergic reactions, and to define prognosis and assess clinical response to immunomodulatory treatments.

Home-Based Up-Dosing in Build-Up Phase of Oral Immunotherapy of Egg Allergy Is Safe and Feasible in Real-World Practice

Oral immunotherapy (OIT) has emerged to build sustained unresponsiveness or tolerance in patients with egg allergy. However, it is important to increase compliance and ensure safety because OIT requires an extended period of time and has a risk of side effects like anaphylaxis. We aimed to show the feasibility and safety of OIT during the build-up phase using a home-based, up-dosing method in children with egg allergy. Sixteen patients aged 4 to 12 years with egg allergy were enrolled. Patients increased the dose of boiled egg white (EW) by 5% per day at home and 25% per month at the hospital, with a target dose of 40 g of boiled EW (4.0 g of EW proteins). A historical control group (n = 16) was matched for age, sex, and clinical characteristics for comparisons with the OIT group. Oral food challenge (OFC) tests were performed after completing the build-up phase. In the OIT group, 93.8% (15/16) of patients achieved desensitization, with only 1 patient discontinuing OIT before the maintenance phase due to repeated allergic reactions. Mild allergic reactions and anaphylaxis occurred in 12 (75.0%) and 2 patients (12.5%), respectively. However, there were no significant adverse reactions such as serious anxiety or life-threatening events that required discontinuation of treatment. On the contrary, only 1 patient (6.3%) in the control group passed an OFC of 40 g of boiled EW during the same period (P < 0.001). Our results suggest that home-based up-dosing protocols using boiled eggs may be safe and feasible for the build-up phase of OIT in children with egg allergy.

Effect of pulsed light treatment on enzymes and protein allergens associated with their structural changes: a review

The pulsed light (PL) technique is used for food and surface decontamination widely. The sterilization effect of PL is well known and identified as the photo-chemical effect. Besides, PL is used to inactivate enzymes, reduce the immunoreactivity of proteins, and change protein function properties at a laboratory level. The current study aims to review the effect of PL on proteins by highlighting the differences between proteins in buffer solutions or food systems. Although PL is known as a non-thermal technique, most studies done on food systems, food temperature raised considerably. Therefore, PL inactivated many enzymes in buffer solution non-thermally, while mostly with a high increase in temperature of a food system. PL reduced food allergens several folds in some foods. However, immunoreactivity responses of some protein were increased after PL treatment. Also, the current study covers the conformational changes of proteins that occur because of PL treatment. Therefore, some techniques used to follow proteins structural changes such as polyacrylamide gel electrophoresis (SDS-PAGE), high-performance liquid chromatography (HPLC), Fourier-transform infrared spectroscopy (FTIR), etc. were defined. Studies reported that PL altered proteins structure differently. For example, some studies reported that PL degraded some proteins, while other studies suggested that PL aggregated proteins. Also, there were contrary results regarding α-helix and ß-sheet concentration for the treated proteins. In conclusion, some techniques, such as amino acid sequencing, specially when some small new fragments proteins appeared on SDS-PAGE, should be used to detect the effect of PL on proteins precisely.

Basophil activation test: Mechanisms and considerations for use in clinical trials and clinical practice

The basophil activation test (BAT) is a functional assay that measures the degree of degranulation following stimulation with allergen or controls by flow cytometry. It correlates directly with histamine release. From the dose-response curve resulting from BAT in allergic patients, basophil reactivity (%CD63⁺ basophils) and basophil sensitivity (EC₅₀ or similar) are the main outcomes of the test. BAT takes into account all characteristics of IgE and allergen and thus can be more specific than sensitization tests in the diagnosis of allergic disease. BAT reduces the need for in vivo procedures, such as intradermal tests and allergen challenges, which can cause allergic reactions of unpredictable severity. As it closely reflects the patients' phenotype in most cases, it may be used to support the diagnosis of food, venom and drug allergies and chronic urticaria, to monitor the natural resolution of food allergies and to predict and monitor clinical the response to immunomodulatory treatments, such as allergen-specific immunotherapy and biologicals. Clinical application of BAT requires analytical validation, clinical validation, standardization of procedures and quality assurance to ensure reproducibility and reliability of results. Currently, efforts are ongoing to establish a platform that could be used by laboratories in Europe and in the USA for quality assurance and certification.

Wheat/Gluten-Related Disorders and Gluten-Free Diet Misconceptions: A Review

In the last 10,000 years, wheat has become one of the most important cereals in the human diet and today, it is widely consumed in many processed food products. Mostly considered a source of energy, wheat also contains other essential nutrients, including fiber, proteins, and minor components, such as phytochemicals, vitamins, lipids, and minerals, that together promote a healthy diet. Apart from its nutritional properties, wheat has a set of proteins, the gluten, which confer key technical properties, but also trigger severe immune-mediated diseases, such as celiac disease. We are currently witnessing a rise in the number of people adhering to gluten-free diets unwarranted by any medical need. In this dynamic context, this review aims to critically discuss the nutritional components of wheat, highlighting both the health benefits and wheat/gluten-related disorders, in order to address common misconceptions associated with wheat consumption.

Oral Immunotherapy (OIT)-related awareness, attitudes, and experiences among a Nationally-Representative Sample of Food Allergy Patients/Caregivers

BACKGROUND

Advances in oral immunotherapy (OIT) have led to recently expanded treatment options for food allergy (FA) patients. However, to inform future outreach efforts and ensure equitable access to emerging treatments, a greater understanding of current OIT-related awareness, attitudes and experiences is needed.

OBJECTIVE

To characterize current OIT awareness, attitudes and experiences among a nationally-representative sample of US adults with FA and parents/caregivers of pediatric patients.

METHODS

A probability-based sample of US adults and parents/caregivers of children with FA was surveyed about OIT-related knowledge, attitudes, and experiences.

RESULTS

Surveys were completed by respondents (N=781) from all 50 states. Overall, 72% did not know what OIT was prior to the survey. Respondents from households earning over $100,000/year or with a college degree each had significantly greater odds of reporting any OIT awareness compared to lower-income (OR=2.0; 95%CI:1.2-3.4) and non-college-educated (OR=1.9; 95%CI:1.2-3.0) respondents. Among respondents familiar/unfamiliar with OIT, 54%/34% reported their expected treatment outcome was to obtain protection against accidental exposure. Among respondents familiar/unfamiliar with OIT, 38%/35% reported their expected treatment outcome to be curing the allergy. Furthermore, 55% of OIT unfamiliar respondents said they would not be comfortable initiating a conversation with their healthcare provider about their suitability for OIT.

CONCLUSION

This study shows that among a nationally-representative sample of FA patients and pediatric caregivers, awareness of OIT is low, and over 95% of patients lack personal experience with OIT. Furthermore, the data suggest current OIT awareness is disproportionately elevated among wealthier, more highly-educated respondents.

Update of the S2k guideline on the management of IgE-mediated food allergies

Not available.

Study protocol of a phase 2, dual-centre, randomised, controlled trial evaluating the effectiveness of probiotic and egg oral immunotherapy at inducing desensitisation or sustained unresponsiveness (remission) in participants with egg allergy compared with placebo (Probiotic Egg Allergen Oral Immunotherapy for Treatment of Egg Allergy: PEAT study)

INTRODUCTION

Egg allergy is the most common food allergy in children but recent studies have shown persistence or delayed resolution into adolescence. As there is currently no effective long-term treatment, definitive treatments that improve quality of life and prevent fatalities for food allergies are required. We have previously shown that a novel treatment comprising a combination of the probiotic Lactobacillus rhamnosus CGMCC 1.3724 with peanut oral immunotherapy (OIT) is highly effective at inducing sustained unresponsiveness, with benefit persisting to 4 years after treatment cessation in the majority of initial treatment responders. In this study, we plan to extend the probiotic food OIT platform to another allergen, namely egg. We describe the protocol for a phase 2, dual-centre, randomised, controlled trial evaluating the effectiveness of probiotic and egg OIT at inducing desensitisation or sustained unresponsiveness (remission) in participants with egg allergy compared with placebo.

METHODS AND ANALYSIS

80 participants aged 5-30 years of age with current egg allergy confirmed by double-blind placebo-controlled food challenge at study screening will be recruited from Australia and Singapore. There are two intervention arms-probiotic and egg OIT (active) or placebo. Interventions are administered once daily for 18 months. The primary outcome is the proportion of participants who attain 8-week sustained unresponsiveness in the active group versus placebo group.

ETHICS AND DISSEMINATION

This study has been approved by the Human Research Ethics Committees at the Royal Children's Hospital (HREC 2019.082) and the National Healthcare Group Domain Specific Review Board (2019/00029). Results will be published in peer-reviewed journals and disseminated via presentations at international conferences.

TRIAL REGISTRATION NUMBER

ACTRN12619000480189.

Addressing Common Misconceptions in Food Allergy: A Review

Background: Food allergies are common, affecting 1 in 13 school children in the United States and their prevalence is increasing. Many misconceptions exist with regards to food allergy prevention, diagnosis and management. Objective: The main objective of this review is to address misconceptions with regards to food allergies and discuss the optimal, evidence-based approach for patients who carry this diagnosis. Observations: Common misconceptions in terms of food allergy prevention include beliefs that breastfeeding and delayed introduction of allergenic foods prevent the development of food allergies. In terms of diagnosis, statements such as ‘larger skin prick tests or/and higher levels of food-specific IgE can predict the severity of food-induced allergic reactions’, or ‘Tryptase is always elevated in food-induced anaphylaxis’ are inaccurate. Additionally, egg allergy is not a contraindication for receiving the influenza vaccine, food-allergy related fatalities are rare and peanut oral immunotherapy, despite reported benefits, is not a cure for food allergies. Finally, not all infants with eczema will develop food allergies and epinephrine auto-injectors may unfortunately be both unavailable and underused in food-triggered anaphylaxis. Conclusions and relevance: Healthcare professionals must be familiar with recent evidence in the food allergy field and avoid common misunderstandings that may negatively affect prevention, diagnosis and management of this chronic disease.

Optimizing Patient Care in Egg Allergy Diagnosis and Treatment

Egg allergy occurs frequently in childhood with a reported prevalence of 1.3-1.6%. Providing optimal care to egg-allergic patients requires knowledge of the most up-to-date developments in both diagnosis and management, as well as effective communication skills, which will engage the patient in the shared decision-making process. This review aims to provide up-to-date information on egg allergy and also serve as a concise guide on optimal patient diagnosis and management. The field of food allergy has seen multiple advances in recent years, including use of component resolved diagnostics, early egg introduction into the infant diet as a way of preventing egg allergy, baked egg introduction and oral immunotherapy as a form of active therapy. Faced with a variety of options and treatment paths, it is important to ensure that patients and families taking part in the decision-making process have fully understood the potential outcomes and trade-offs and can undertake a detailed discussion of all options that are available to them. Shared decision-making remains the cornerstone of optimal patient care.

Differences in oral food challenge reaction severity based on increasing age in a pediatric population

BACKGROUND

Food allergy reactions range from mild to severe with differences in age appearing to be an important factor associated with reaction severity.

OBJECTIVE

To define differences in oral food challenge (OFC) reaction severity in pediatric patients from infancy to adolescence using objective clinical outcomes and standardized reaction grading tools.

METHODS

Retrospective review of all positive OFC results at 2 large institutions between September 2016 and February 2019. Reaction severity was defined by presence of cardiovascular, neurologic, lower respiratory, or laryngeal symptoms, epinephrine requirement, and grading using 2 established food allergy reaction scales.

RESULTS

Infants and toddlers had fewer reactions involving cardiovascular, neurologic, lower respiratory, or laryngeal symptoms compared with older age groups. Epinephrine was also required less frequently during reactions in infants and toddlers, compared with older age groups. There was no difference in reaction severity in infants and toddlers based on clinical history of eczema. Increasing age was significantly correlated with increased epinephrine requirement (R² = 0.12, P = .002), elevated Consortium of Food Allergy Research score (R² = .012, P = .003), and approached significance for increased Practical Allergy score (R² = .005, P = .05). History of asthma and sesame allergy were identified to be positively correlated with more severe reactions.

CONCLUSION

Infants and young toddlers have less severe reactions during OFCs compared with older age groups supporting early food introduction practices. In children under 12 months of age, severe reactions are most rare calling into question screening practices using specific allergy testing before food introduction. Standardized reaction grading tools may be valuable instruments to categorize reaction severity during OFCs.

Food Allergy: Catering for the Needs of the Clinician

The practice of food allergy (FA) for clinicians has boomed, with a dramatic rise in the number of patients and families seeking care and with many advances on several fronts. The practice itself sometimes is evidence-based science and sometimes an art of pattern and phenotype recognition. This article examines the tools for diagnosis and management and therapy options available to physicians providing care for patients with FA. The article touches on pressing needs of clinicians and highlights the rapid and important movements in national and international support and advances that will have a positive impact on the field of FA.

An Insulin-Inspired Supramolecular Hydrogel for Prevention of Type 1 Diabetes

Supramolecular peptide hydrogel has shown promising potential in vaccine development largely because of its ability to function both as antigen depot and immune adjuvant. Nap-GdFdFdY, a tetrapeptide hydrogel that has been previously reported to exhibit adjuvant effect, is inadvertently found to contain conserved peptide sequence for insulin, proinsulin, and glutamic acid decarboxylase, 3 major autoantigens for the autoimmune type 1 diabetes (T1D). At present, despite being managed clinically with insulin replacement therapy, T1D remains a major health threat with rapidly increasing incidences, especially in children and young adults, and antigen-specific immune tolerance induction has been proposed as a feasible approach to prevent or delay T1D progression at an early stage. Here, it is reported that innoculation of Nap-GdFdFdY leads to complete protection of nonobese diabetic (NOD) mice from T1D development till the age of 36 weeks. Better maintenance of pancreatic islet morphology with minimal immune cell infiltration is also observed from mice exposed to Nap-GdFdFdY. This beneficial impact is mainly due to its facilitative role on enhancing peripheral T regulatory cell (Treg) population, shown as increased splenic Treg percentage, and function, demonstrated by maintenance of circulating TGF-β1 level. Serum cytokine microarray data further implicate a "buffering" role of Nap-GdFdFdY on systemic inflammatory tone in NOD mice. Thus, with its versatility, applicability, and excellent potency, Nap-GdFdFdY is posited as a novel therapeutic intervention for T1D.

Mechanisms of oral immunotherapy

Food allergy presents a significant global health concern with up to 10% of the population affected in developed nations and a steadily increasing prevalence. In many cases, particularly with peanut, tree nut and shellfish, food allergy is a lifelong and potentially life-threatening diagnosis. While no 'cure' for IgE-mediated food allergy exists, oral immunotherapy (OIT) is a promising treatment modality with the peanut OIT drug Palforzia (Aimmune Therapeutics) the only treatment for food allergy that is currently approved by the United States Food and Drug Administration. OIT primarily induces a state of desensitization with only a minority of subjects achieving sustained unresponsiveness, a state of limited clinical remission that appears to be immunologically distinct from natural tolerance. Early humoural changes during OIT include an initial increase in allergen-specific IgE, which eventually decreases to below baseline levels as OIT progresses, and a gradual increase in allergen-specific IgA and IgG4 that continues throughout the course of OIT. Basophil hyporesponsiveness and decreased skin prick test wheal size are observed within the first year of OIT, and persistence after completion of therapy has been associated with sustained unresponsiveness. In the T-cell compartment, there is an initial expansion followed by a decline in the number and activity of T helper 2 (TH 2) cells, the latter of which may be dependent on an expansion of IL-10-producing cells, including regulatory T-cells. Our understanding of the immunomodulatory effects of OIT continues to evolve, with new technologies such as single-cell transcriptional profiling and antibody epitope analysis allowing for more detailed study of T-cell and B-cell responses to OIT. In this review, we present evidence to illustrate what is currently known about the immunologic changes induced by OIT, explore potential mechanisms and emphasize knowledge gaps where future research is needed.

An Approach to the Office-Based Practice of Food Oral Immunotherapy

Oral immunotherapy (OIT) provides an active treatment option for patients with food allergies. OIT may improve quality of life and raise the threshold at which a patient with food allergy may react to an allergen, but it is a rigorous therapy that requires a high degree of commitment by the clinician, patients, and families. Recent guidelines from the Canadian Society for Allergy and Clinical Immunology have provided a framework for the ethical, evidence-based, and patient-oriented clinical practice of OIT, and the European Academy of Allergy, Asthma, and Immunology guidelines have also recommended that OIT can be used as a potential treatment. The recent Food and Drug Administration approval of an OIT pharmaceutical has accelerated the adoption of OIT. This review provides a summary of the recent Canadian Society for Allergy and Clinical Immunology guidelines and a consensus of practical experience of clinicians across the United States and Canada related to patient selection, office and staff preparation, the general OIT process, OIT-related reaction management, and treatment outcomes.

Consensus on DEfinition of Food Allergy SEverity (DEFASE) an integrated mixed methods systematic review

BACKGROUND AND AIMS

The term "Food Allergy" refers to a complex global health problem with a wide spectrum of severity. However, a uniform definition of severe food allergy is currently missing. This systematic review is the preliminary step towards a state-of-the-art synopsis of the current evidence relating to the severity of IgE-mediated food allergy; it will inform attempts to develop a consensus to define food allergy severity by clinicians and other stakeholders.

METHODS

We undertook a mixed-methods systematic review, which involved searching 11 international biomedical databases for published studies from inception to 31 December 2019. Studies were independently screened against pre-defined eligibility criteria and critically appraised by established instruments. The substantial heterogeneity of included studies precluded meta-analyses and, therefore, narrative synthesis of quantitative and qualitative data was performed.

RESULTS

We found 23 studies providing eligible primary data on symptom-specific severity of food allergic reactions, and 31 previously published symptom-severity scoring systems referred to food allergic reactions. There were seven studies which assessed quality-of-life measures in patients (and family members) with different food allergy severity and two studies that investigated the economic burden of food allergy severity. Overall, the quality and the global rating of all included studies were judged as being moderate.

CONCLUSIONS

There is heterogeneity among severity scoring systems used and even outcomes considered in the context of severity of food allergy. No score has been validated. Our results will be used to inform the development of an international consensus to define the severity of food allergy.

SYSTEMATIC REVIEW REGISTRATION

A protocol was prospectively registered with the International Prospective Register of Systematic Reviews (PROSPERO) database with the registration number CRD42020183103 (https://www.crd.york.ac.uk/prospero/#recordDetails).

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.

IgE-mediated food allergy throughout life

Food allergy (FA) has become an increasing problem throughout the world. Over the last 2 decades, the frequency of FA has increased in both children and adults. The prevalence differs according to the research methodology, age, and geographic regions, ranging between 2.0% and 10.0%. The most common form of FA is immunoglobulin E (IgE)-mediated FA. In this form, patients may present with life-threatening conditions, such as anaphylaxis, or milder conditions, such as urticaria, angioedema, sneezing, and nausea alone. The gold standard in the diagnosis of FA is oral provocation tests. Epidermal skin prick tests and specific IgE measurements, as well as component-resolved diagnostic techniques are helpful in the diagnosis and follow-up of patients. In this review, the epidemiology, diagnosis, follow-up, and prognosis of IgE-mediated FA in children and adults were discussed and some specific forms of FA, such as pollen FA syndrome, alpha-gal allergy, and food-dependent exercise-induced anaphylaxis were explained.

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.

Pre- and Neonatal Imprinting on Immunological Homeostasis and Epithelial Barrier Integrity by Escherichia coli Nissle 1917 Prevents Allergic Poly-Sensitization in Mice

A steady rise in the number of poly-sensitized patients has increased the demand for effective prophylactic strategies against multi-sensitivities. Probiotic bacteria have been successfully used in clinics and experimental models to prevent allergic mono-sensitization. In the present study, we have investigated whether probiotic bacteria could prevent poly-sensitization by imprinting on the immune system early in life. We used two recombinant variants of probiotic Escherichia coli Nissle 1917 (EcN): i) EcN expressing birch and grass pollen, poly-allergen chimera construct (EcN-Chim), and ii) an “empty” EcN without allergen expression (EcN-Ctrl). Conventional mice (CV) were treated with either EcN-Chim or EcN-Ctrl in the last week of the gestation and lactation period. Gnotobiotic mice received one oral dose of either EcN-Chim or EcN-Ctrl before mating. The offspring from both models underwent systemic allergic poly-sensitization and intranasal challenge with recombinant birch and grass pollen allergens (rBet v 1, rPhl p 1, and rPhl p 5). In the CV setting, the colonization of offspring via treatment of mothers reduced allergic airway inflammation (AAI) in offspring compared to poly-sensitized controls. Similarly, in a gnotobiotic model, AAI was reduced in EcN-Chim and EcN-Ctrl mono-colonized offspring. However, allergy prevention was more pronounced in the EcN-Ctrl mono-colonized offspring as compared to EcN-Chim. Mono-colonization with EcN-Ctrl was associated with a shift toward mixed Th1/Treg immune responses, increased expression of TLR2 and TLR4 in the lung, and maintained levels of zonulin-1 in lung epithelial cells as compared to GF poly-sensitized and EcN-Chim mono-colonized mice. This study is the first one to establish the model of allergic poly-sensitization in gnotobiotic mice. Using two different settings, gnotobiotic and conventional mice, we demonstrated that an early life intervention with the EcN without expressing an allergen is a powerful strategy to prevent poly-sensitization later in life.

IgE in the pathophysiology and therapy of food allergy

Food allergy is becoming a major public health issue, with no regulatory approved therapy to date. Food allergy symptoms range from skin rash and gastrointestinal symptoms to anaphylaxis, a potentially fatal systemic allergic shock reaction. IgE antibodies are thought to contribute importantly to key features of food allergy and anaphylaxis, and measurement of allergen-specific IgE is fundamental in diagnosing food allergy. This review will discuss recent advances in the regulation of IgE production and IgE repertoires in food allergy. We will describe the current understanding of the role of IgE and its high-affinity receptor FcεRI in food allergy and anaphylaxis, by reviewing insights gained from analyses of mouse models. Finally, we will review data derived from clinical studies of the effect of anti-IgE therapeutic monoclonal antibodies (mAbs) in food allergy, and recent insight on the efficiency and mechanisms through which these mAbs block IgE effector functions.

A Randomized, Open-Label Trial of Hen's Egg Oral Immunotherapy: Efficacy and Humoral Immune Responses in 50 Children

BACKGROUND

Egg allergy is the second most common food allergy in children. Persistent food allergy increases the risk of anaphylaxis and reduces the quality of life.

OBJECTIVE

To determine the efficacy of oral immunotherapy (OIT) with raw egg white powder and study its effects on humoral responses in children with persistent egg allergy.

METHODS

Fifty children aged 6 to 17 years with egg allergy, diagnosed by double-blind, placebo-controlled food challenge, were randomized 3:2 to 8 months of OIT with a maintenance dose of 1 g of egg white protein or 6 months of avoidance after which the avoidance group crossed over to OIT. We examined changes in IgE, IgG₄, and IgA concentrations to Gal d 1-4 during OIT compared with avoidance and assessed clinical reactivity at 8 and 18 months.

RESULTS

After 8 months, 22 of 50 children (44%) on OIT and 1 of 21 (4.8%) on egg avoidance were desensitized to the target dose, 23 of 50 (46%) were partially desensitized (dose <1 g), and 5 of 50 (10%) discontinued. IgG₄ concentrations to Gal d 1-4 and IgA to Gal d 1-2 increased significantly, whereas IgE to Gal d 2 decreased. A heatmap analysis of the IgE patterns revealed 3 distinct clusters linked with the clinical outcome. High baseline egg white-specific IgE and polysensitization to Gal d 1-4 related with failure to achieve the maintenance dose at 8 months. After 18 months of treatment, 36 of 50 patients (72%) were desensitized and 8 of 50 (16%) partially desensitized.

CONCLUSIONS

OIT with raw egg enables liberation of egg products into the daily diet in most patients. Subjects with high egg white-specific IgE concentrations and sensitization to multiple egg allergen components at baseline benefit from prolonged treatment.

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.

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.

Orally desensitized mast cells form a regulatory network with Treg cells for the control of food allergy

Oral immunotherapy (OIT) is an effective approach to controlling food allergy. Although the detailed molecular and cellular mechanisms of OIT are unknown currently, they must be understood to advance the treatment of allergic diseases in general. To elucidate the mechanisms of OIT, especially during the immunological transition from desensitization to allergy regulation, we generated a clinical OIT murine model and used it to examine immunological events of OIT. We found that in mice that completed OIT successfully, desensitized mast cells (MCs) showed functionally beneficial alterations, such as increased induction of regulatory cytokines and enhanced expansion of regulatory T cells. Importantly, these regulatory-T-cell-mediated inhibitions of allergic responses were dramatically decreased in mice lacking OIT-induced desensitized MC. Collectively, these findings show that the desensitization process modulates the activation of MCs, leading directly to enhanced induction of regulatory-T-cell expansion and promotion of clinical allergic unresponsiveness. Our results suggest that efficiently inducing regulatory MCs is a novel strategy for the treatment of allergic disease.

Oral Immunotherapy and Basophil and Mast Cell Reactivity in Food Allergy

Basophil activation tests (BATs) can closely monitor, in vitro, a patient's propensity to develop type I hypersensitivity reactions. Because of their high specificity and sensitivity, BATs have become promising diagnostic tools, especially in cases with equivocal clinical histories, skin prick test results, and/or levels of specific IgE to allergen extracts. BATs also are useful as tools for monitoring the effects of treatment, since oral immunotherapy (OIT) studies report a diminution in patients' basophil responsiveness over the course of OIT. This review will discuss the BAT findings obtained before, during, and after OIT for food allergy. We will mainly focus on the association of basophil responsiveness, and alterations in basophil surface markers, with clinical outcomes and other clinical features, such as blood levels of specific IgG and IgE antibodies. The detailed analysis of these correlations will ultimately facilitate the use of BATs, along with other blood biomarkers, to differentiate short-term desensitization versus sustained unresponsiveness and to improve treatment protocols. Given the critical anatomic location of mast cells adjacent to the many IgE+ plasma cells found in the gastrointestinal tissues of allergic individuals, we will also discuss the role of gastrointestinal mast cells in manifestations of food allergies.

IgE and IgG Antibodies as Regulators of Mast Cell and Basophil Functions in Food Allergy

Food allergy is a major health issue, affecting the lives of 8% of U.S. children and their families. There is an urgent need to identify the environmental and endogenous signals that induce and sustain allergic responses to ingested allergens. Acute reactions to foods are triggered by the activation of mast cells and basophils, both of which release inflammatory mediators that lead to a range of clinical manifestations, including gastrointestinal, cutaneous, and respiratory reactions as well as systemic anaphylaxis. Both of these innate effector cell types express the high affinity IgE receptor, FcϵRI, on their surface and are armed for adaptive antigen recognition by very-tightly bound IgE antibodies which, when cross-linked by polyvalent allergen, trigger degranulation. These cells also express inhibitory receptors, including the IgG Fc receptor, FcγRIIb, that suppress their IgE-mediated activation. Recent studies have shown that natural resolution of food allergies is associated with increasing food-specific IgG levels. Furthermore, oral immunotherapy, the sequential administration of incrementally increasing doses of food allergen, is accompanied by the strong induction of allergen-specific IgG antibodies in both human subjects and murine models. These can deliver inhibitory signals via FcγRIIb that block IgE-induced immediate food reactions. In addition to their role in mediating immediate hypersensitivity reactions, mast cells and basophils serve separate but critical functions as adjuvants for type 2 immunity in food allergy. Mast cells and basophils, activated by IgE, are key sources of IL-4 that tilts the immune balance away from tolerance and towards type 2 immunity by promoting the induction of Th2 cells along with the innate effectors of type 2 immunity, ILC2s, while suppressing the development of regulatory T cells and driving their subversion to a pathogenic pro-Th2 phenotype. This adjuvant effect of mast cells and basophils is suppressed when inhibitory signals are delivered by IgG antibodies signaling via FcγRIIb. This review summarizes current understanding of the immunoregulatory effects of mast cells and basophils and how these functions are modulated by IgE and IgG antibodies. Understanding these pathways could provide important insights into innovative strategies for preventing and/or reversing food allergy in patients.

Use of emergency backup resources during open food challenges at a pediatric tertiary care center

Background

Oral food challenge (OFC) remains the criterion standard diagnostic procedure for food allergy. Although the need for OFCs has increased, some allergists may not perform them due to the risk for adverse events and lack of backup resources.

Objective

The study aimed to elucidate the frequency of reactions in which emergency backup resources were used and reported on various challenge outcomes at a tertiary pediatric hospital.

Methods

We retrospectively reviewed children and young adults (ages, 0-21 years) who completed OFCs in 2013-2018 at Cleveland Clinic Children's Hospital. Demographics, atopic history, culprit food, reaction history, and diagnostic testing as well as challenge details and outcomes were collected and analyzed.

Results

A total of 1269 challenges of 812 unique patients ages 5 months to 21 years were reviewed. More than half of challenges were performed in patients with a history of a reaction and positive testing result before challenge. The foods with the highest proportion of allergic outcomes were egg, sesame, and baked egg. More than one-third of challenge reactions were grade 3 or 4 anaphylaxis when using a food-induced anaphylaxis grading scale. Epinephrine was used for reactions in 7.2% of all challenges. Reactions in five challenges (0.4%) prompted utilization of backup emergency resources.

Conclusion

On review of nearly 1300 OFCs, emergency backup resources were rarely used, despite a large proportion of moderate-to-severe reactions. The need for backup resources during food challenges is rare, which suggests that most typical allergy offices are able to treat OFC reactions.

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.

IgE and mast cells: The endogenous adjuvant

Mast cells and IgE are most familiar as the effectors of type I hypersensitivity reactions including anaphylaxis. It is becoming clear however that this pair has important immunomodulatory effects on innate and adaptive cells of the immune system. In this purview, they act as endogenous adjuvants to ignite evolving immune responses, promote the transition of allergic disease into chronic illness and disrupt the development of active mechanisms of tolerance to ingested foods. Suppression of IgE-mediated mast cell activation can be exerted by molecules targeting IgE, FcɛRI or signaling kinases including Syk, or by IgG antibodies acting via inhibitory Fcγ receptors. In 2015 we reviewed the evidence for the adjuvant functions of mast cells. This update includes the original text, incorporates some important developments in the field over the past five years and discusses how interventions targeting these pathways might have promise in the development of strategies to treat allergic disease.