Specific oral immunotherapy in food allergic patients: transient or persistent tolerance?

INTRODUCTION: The first therapeutic choice for food allergy is avoidance of the responsible food, but when this approach is not possible, specific oral desensitization could be considered as a good alternative. It is not clear yet whether the acquired tolerance is transient or persistent. AIM: We report on a subset of 13 patients of a larger study, treated successfully with specific oral tolerance induction who experienced secondary loss of tolerance after a period of allergen avoidance. MATERIAL AND METHODS: Thirteen patients affected by IgE-mediated food allergy: to cow milk (3 patients), to hen egg (3 patients), to cod fish (2 patients), to peanuts (1 patient) and to corn (1 patient) confirmed by a complete allergological workup and a double-blind placebo-controlled food challenge (DBPCFC), were treated with sublingual-oral desensitization. After the interruption of the maintenance phase, the laboratory tests were performed and 12 of 13 patients underwent DBPCFC. RESULTS: Oral specific desensitization was completed successfully in all the 13 reported patients. At different times after the end of treatment, they decided, on their own initiative, to stop the ingestion of incriminated food. A new food allergen re-exposure caused adverse reactions in 12 of 13 patients. The detection of specific IgE and IgG4 during the period of allergen avoidance showed an increase in or a stable level of specific IgE and a decrease in specific IgG4 in 8 patients. CONCLUSIONS: According to our experience, the tolerance obtained through the desensitizing treatment is transient and so the regular allergen intake is necessary for its maintenance.

Inflammatory events during food protein-induced enterocolitis syndrome reactions.

BACKGROUND: An increasing number of infants are diagnosed with food protein-induced enterocolitis syndrome (FPIES), a non-IgE-mediated food allergy. Until now, T-cell, food-specific mechanisms have been hypothesized. METHODS: Sixteen children (11M, 5F), affected by FPIES from cow's milk, wheat, fruit, rice, and others, experienced 25 acute episodes managed at our emergency department (ED) and eight FPIES reactions during oral food challenges (OFC). We compared the laboratory data in resting conditions, in the absence of infectious diseases, with data collected during the 25 acute ED episodes (blood samples drawn at 2-12 hours) and the eight positive OFCs (three samples at 2, 6, and 12 hours). The onset of symptoms was used as a reference time point. RESULTS: In basal conditions, total IgE, WBC, neutrophil and eosinophil count, CRP, and SGPT were found normal. LDH and SGOT values were high (627.81±97.88 and 45.75±10.26 UI/L, respectively). During ED reactions, LDH and SGOT increased to 794.21±247.28 (P=.028) and 51.08±16.99 UI/L (P=.14) and neutrophils count and CRP to 8.44±3.82×103 /µL (P=.0009) and 3.27±5.73 mg/dL (P=.0014), respectively. During positive OFC, LDH and SGOT did not vary significantly; CRP increased from 0.14±0.18 to 2.49±3.65 mg/dL (P=.00189) and neutrophil count from 2.79±1.42 to 7.10±3.98×103 /µL (P=.00096). CONCLUSIONS: FPIES reactions are characterized by neutrophilia and by a time-dependent, significant increase in CRP, indicating that inflammatory mechanisms are in place. This suggests new directions for research on FPIES pathogenesis.

Probiotics, Prebiotics & Food allergy Prevention: Clinical Data in Children.

PURPOSE OF REVIEW: there are accruing evidences on the role of the intestinal microbiota in the development of allergic diseases among infants. Elaborating on this theoretical basis, studies did assess the possibilities to prevent allergic diseases in infancy through manipulation of the intestinal microbiota. We review here such studies. RECENT FINDINGS: interventional studies led to conflicting conclusions on the possible role of probiotics and prebiotics in allergy prevention. Two metanalyses published in 2015 did reconcile all data. Guidelines have been predicated on such studies using the GRADE methodology. SUMMARY: the guidelines for allergy prevention suggest for the first time the use of probiotics and prebiotics. The existing evidences stand for a use of such supplementation in particular for the prevention of eczema. As there is no evidence so far of superiority of one probiotic strand over the others, they should be considered as class and not as individual products.

Hypersensitivity to major panallergens in a population of 120 patients.

INTRODUCTION: Lipid transfer proteins (LTP), profilin and PR-10 are the most important panallergens in central and southern Italy. Lipid transfer proteins are stable molecules, predominantly present in the fruit peel, which can induce systemic symptoms after ingestion of vegetables. Profilin and PR-10 are randomly distributed in the pulp and peel. Both are labile proteins and usually determine reactions restricted to the oral cavity. Panallergens-specific IgE may cross-react with homologues from different plant sources, due to their conserved structure. AIM: To assess the pattern of sensitization to panallergens and the correlation with the clinical history and the allergological evaluation of food and aeroallergens. MATERIAL AND METHODS: One hundred and twenty patients with adverse reactions after vegetables ingestion underwent skin prick tests (SPT) with commercial extracts of plant-derived foods and inhalant allergens and commercial extracts of LTP, profilin and PR-10. RESULTS: Many patients presented positive SPT with different plant-food allergens. We found that 76 patients were sensitized to LTP, 14 to profilin and 5 to PR-10. In the LTP-sensitized group, 64 (84%) patients suffered from systemic symptoms while the patients sensitized only to profilin referred the oral allergy syndrome. CONCLUSIONS: This study shows a high rate of sensitization to LTP in our population according to the literature about food allergy in our geographical area and confirms the literature data about the symptoms referred by patients with sensitization to panallergens. Panallergens should be considered as clinically relevant food allergens.

Botanical Impurities in the Supply Chain: A New Allergenic Risk Exacerbated by Geopolitical Challenges.

BACKGROUND: The supply chains of food raw materials have recently been heavily influenced by geopolitical events. Products that came from, or transited through, areas currently in conflict are now preferentially supplied from alternative areas. These changes may entail risks for food safety. METHODS: We review the potential allergenicity of botanical impurities, specifically vegetable contaminants, with particular attention to the contamination of vegetable oils. We delve into the diverse types of botanical impurities, their sources, and the associated allergenic potential. Our analysis encompasses an evaluation of the regulatory framework governing botanical impurities in food labeling. RESULTS: Unintended plant-derived contaminants may manifest in raw materials during various stages of food production, processing, or storage, posing a risk of allergic reactions for individuals with established food allergies. Issues may arise from natural occurrence, cross-contamination in the supply chain, and contamination at during production. The food and food service industries are responsible for providing and preparing foods that are safe for people with food allergies: we address the challenges inherent in risk assessment of botanical impurities. CONCLUSIONS: The presence of botanical impurities emerges as a significant risk factor for food allergies in the 2020s. We advocate for regulatory authorities to fortify labeling requirements and develop robust risk assessment tools. These measures are necessary to enhance consumer awareness regarding the potential risks posed by these contaminants.

A Bayesian hierarchical model for identifying epitopes in peptide microarray data.

Peptide Microarray Immunoassay (PMI for brevity) is a novel technology that enables researchers to map a large number of proteomic measurements at a peptide level, providing information regarding the relationship between antibody response and clinical sensitivity. PMI studies aim at recognizing antigen-specific antibodies from serum samples and at detecting epitope regions of the protein antigen. PMI data present new challenges for statistical analysis mainly due to the structural dependence among peptides. A PMI is made of a complete library of consecutive peptides. They are synthesized by systematically shifting a window of a fixed number of amino acids through the finite sequence of amino acids of the antigen protein as ordered in the primary structure of the protein. This implies that consecutive peptides have a certain number of amino acids in common and hence are structurally dependent. We propose a new flexible Bayesian hierarchical model framework, which allows one to detect recognized peptides and bound epitope regions in a single framework, taking into account the structural dependence between peptides through a suitable latent Markov structure. The proposed model is illustrated using PMI data from a recent study about egg allergy. A simulation study shows that the proposed model is more powerful and robust in terms of epitope detection than simpler models overlooking some of the dependence structure.

IgE-immunoadsorption for severe allergy to multiple foods: A case series of five children.

Background: Children with severe food allergy may present high risk of fatal anaphylaxis and a highly impaired quality of life. Anti IgE-treatment has been shown to be a promising approach as monotherapy for severe allergy to multiple foods. However, very high serum total IgE levels may limit its use.This study aims to assess the efficacy of IgE-selective immunoadsorption (IgE-IA) on total IgE levels and threshold of reactivity to the culprit foods in children with history of severe anaphylaxis due to multiple foods and allergic comorbidities. Methods: In this single-center, prospective, open-label efficacy study we evaluated children with severe asthma, allergy to 2+foods and total IgE levels >2300 kUI/L. To establish the food reactivity threshold, each patient underwent oral food challenges (OFCs) before and after IgE-IA. Results: Five patients (4 males; age, 12.2 ± 5 years, mean ± SD) underwent an average of 3 (range 2-4) sessions of IgE-IA. Each session reduced IgE levels by a mean of 1958.87 kUI/L. After the IgE-IA cycle, serum total IgE dropped from 3948 ± 1652.7 (mean ± SD) to 360.8 ± 71.9 kUI/L (-10.9 folds; p = 0.01). The threshold of reactivity (No Observed Adverse Effect Level, NOAEL) tested at OFCs for the culprit foods (4 baked-milk + 2 baked-egg + 1 lentil + 2 hazelnut + 1 wheat) increased overall from 21.5 (median, IQR 1.5-82.6) protein milligrams to 1115 (837.2-4222.8) milligrams (p < 0.001), ie, up to 51.8 times higher than baseline. 8/10 OFCs were negative after IgE-IA. Conclusions: IgE-IA increased food threshold quickly. It can be considered in well-selected patients with severe food allergies and high IgE-levels especially if otherwise eligible to anti IgE treatment.

Reactivity to allergenic food contaminants: A study on products on the market.

BACKGROUND: The frequency and severity of reactions in food-allergic consumers exposed to unintentional food allergen contamination during production is unknown. To warn allergic consumers, it has been suggested for pre-packaged foods to be precautionary labelled when the food allergen contamination may exceed the amount to which 1%-5% of the population could react (ED01-ED05). ED01 for hazelnut and milk have been estimated at 0.1 and 0.2 mg, respectively, by the Voluntary Incidental Trace Allergen Labelling (VITAL) initiative. The respective reference doses recommended by the FAO/WHO Codex consultation are 3 and 2 mg. We evaluated the reactivity to potential traces of milk and hazelnut allergens in allergen-free pre-packaged products by children affected by severe allergies to milk and hazelnuts. METHODS: Oral Food Challenges with commercially available hazelnut-free wafer biscuits and milk-free chocolate pralines were administered to patients with severe food allergies to hazelnut and cow's milk, respectively. Contamination levels of milk or hazelnut allergens were measured using chromatographic separation interfaced with triple quadrupole mass spectrometry. RESULTS: No hazelnut allergic patient showed allergic reactions to exposure to biscuits, nor any milk allergic patient displayed allergic reactions to the dark chocolate praline. While no hazelnut trace was detected in biscuits, the praline was found to be contaminated by milk at concentrations ranging between 8 and 35 mg total protein/kg food. In our dose model, these amounts exceeded 1.5-10 times the VITAL ED01 and reached the threshold suggested by the FAO/WHO Codex consultation. CONCLUSIONS: Upon the consumption of food products available on the market, many patients with severe food allergies tolerate significantly higher doses of allergen than reference doses indicated in the VITAL system used for precautionary allergen labelling. These doses support the safety of the FAO/WHO recommended reference doses.

Down Syndrome in FPIES: An Overwhelming and Unexpected Prevalence.

Down syndrome (DS) is one of the most common chromosomal anomalies. Gastrointestinal disorders in DS are predominantly related to anatomical anomalies and celiac disease. In 2015, the first two cases of non-IgE-mediated food allergy in patients with DS were described. However, gastrointestinal symptoms experienced by subjects with DS have never been related to a possible non-IgE-mediated food allergy and a Food Protein-induced Enterocolitis syndrome (FPIES). A retrospective descriptive single-center study was conducted. Subjects included were children with acute FPIES who entered our institutional follow-up protocol between January 2013 and January 2020. Among the 85 patients (forty-nine boys-57.6%), ten (11.76%) were children with DS. In our population, the FPIES triggers included different foods (such as milk, egg, fruit, fish, wheat, soy, beef, etc.). Nine patients with DS showed FPIES reactions after ingesting cow's milk (one even with beef and three with soy), while the last one was affected by FPIES to fish. Considering the subgroup of patients affected by cow's milk FPIES (40 subjects overall), 22.5% had a diagnosis of DS. Patients with DS experienced acute FPIES reactions with a severity degree slightly higher than that reported in other patients, ranging from mild-moderate to severe or very severe. During the acute reactions, the patients with DS showed increased white blood cell production, absolute neutrophil count and C-reactive protein levels. This series provides a starting point for novel hypothesis-testing clinical research and possible specific immunological alterations in FPIES children with or without DS.

Pharmacotherapy in allergy medicine: from 'ipse dixit' to the evidence-based medicine.

PURPOSE OF REVIEW: The aim of the article is to examine the contributions made in recent years by evidence-based medicine to the understanding, positioning, and use of drugs for the treatment of the main allergic conditions. RECENT FINDINGS: Several antiasthmatic drugs have been reappraised for their efficacy characteristics and drug interactions in Cochrane reviews. The Allergic Rhinitis and its Impact on Asthma (ARIA) guidelines have been reformulated in evidence-based medicine (EBM) terms in 2017; over these years, new point of care instruments contributed to the approximation of the guidelines to real life by drawing from the patients themselves information that allows to finely modeling the pharmacological suggestions. Last, at the time of the emergence of new drugs for the treatment of peanut allergy, new systematic reviews have helped to focus on the most suitable reference outcomes with the aim to respond promptly and adherently to patients' needs. SUMMARY: EBM has contributed to changes in the GINA guidelines in the last two years. It has been instrumental in translating the ARIA guidelines in real life. It has also contributed to profiling the potential and limitations of oral peanut immunotherapy. In allergy medicine, EBM is a formidable aid for the advancement of knowledge.

Food protein-induced enterocolitis syndrome epidemiology, diagnosis, and treatment.

PURPOSE OF REVIEW: In the last years, the interest of the scientific community toward food protein-induced enterocolitis syndrome (FPIES) has grown exponentially. We review here the peculiar characteristics of this syndrome. RECENT FINDINGS: The recent publication of the First International Consensus Guidelines allowed a positive interaction between different research groups with the aim of improving the diagnosis and management of patients affected by FPIES. SUMMARY: Several fixed points have been placed on the diagnosis and management, but further studies are needed to clarify the many shadows that still surround different aspects of the syndrome, especially regarding the pathophysiology.

Microbiota in non-IgE-mediated food allergy.

PURPOSE OF REVIEW: To perform a nonsystematic review of the literature on the microbiota in the different types of non-IgE-mediated food allergy. RECENT FINDINGS: The commonest non-IgE-mediated disorders managed by allergists include: eosinophilic esophagitis, food protein-induced enteropathy, food protein-induced enterocolitis syndrome, and food protein-induced allergic proctocolitis. The review of the literature describes how at phylum level we observe an increase of Proteobacteria in eosinophilic esophagitis esophageal microbiota and in food protein-induced enterocolitis syndrome, and food protein-induced allergic proctocolitis gut microbiota, while we observe an increase of Bacteroidetes in healthy controls. Several studies endorse the concept that a bloom of Proteobacteria in the gut reflects dysbiosis or an unstable gut microbial community structure. In several studies, the type of diet, the use of probiotics and in a single experience the use of fecal microbiota transplantation has produced significant variations of the microbiota. SUMMARY: Genetic factors alone cannot account for the rapid rise in food allergy prevalence and the microbiome might be contributing to allergy risk. Our review showed that common features of the pathological microbiota among different types of non-IgE-mediated food allergy can be identified. These evidences suggest a possible role of the microbiota in the pathogenesis and non-IgE-mediated food allergies and the need to understand the effects of its modulation on the disorders themselves.

Allergy to food additives.

PURPOSE OF REVIEW: To provide an update of the studies concerning the diagnosis and management of food additives allergy. RECENT FINDINGS: Additives improve specific characteristics of food products, but they may induce allergic even life-threatening reactions. Physical examination and medical history are basic to assess specific in-vivo and in-vitro tests. The only treatment for allergic patients consists in avoiding the food containing culprit additives. High-risk patients should be able to recognize severe reactions and self-manage them. SUMMARY: The prevalence of adverse reactions to food additives is low, and it may depend on comorbidities, like asthma or chronic idiopathic urticaria. Food labels may help the correct identification of ingredients. Natural additives like spices should cause immediate reactions because of a pollen-sensitization or panallargen proteins presence. Additive-free diets may help the patient care, but the authors suggest assessing an oral food challenge with the culprit substance if there are no contraindications.

Impact of Omalizumab on Food Allergy in Patients Treated for Asthma: A Real-Life Study.

BACKGROUND: The effects of omalizumab on food allergy thresholds have been little studied. OBJECTIVE: To assess the real-life effects of omalizumab on food threshold tolerability in children treated for severe asthma. METHODS: In this observational, real-life, efficacy study, we reviewed the food allergen thresholds of patients with severe asthma, as well as their immediate reactions to 2+ foods before and after a 4-month treatment with omalizumab. We also evaluated their control of asthma and their quality of life, as measured by Pediatric Quality of Life Inventory (PedsQL). RESULTS: Fifteen children, allergic to 37 foods, were evaluated. Omalizumab induced an increase in the allergen threshold for milk, egg, wheat, and hazelnut from a mean 1012.6 ± 1464.5 mg protein to 8727 ± 6463.3 eliciting dose (P < .001). A total of 70.4% of subjects tolerated the complete challenge dose after 4 months of treatment with omalizumab. These foods were reintroduced in the patients' diet without the need for any oral immunotherapy procedures. The remaining foods were partially tolerated. The number of reactions to the unintended ingestion of allergenic foods over 4 months dropped from 47 to 2. The PedsQL increased from 61 ± 5.32 to 87 ± 7.33 (parental judgment; P < .001) and from 65 ± 7.39 to 90 ± 4.54 (patients' judgment; P < .001). The mean cost of omalizumab was €1311.63 per month. CONCLUSIONS: During treatment with omalizumab for severe uncontrolled asthma, the food allergen threshold increases to 8.6 times its original value. The quality of life of patients also increased, due to a better asthma control and a reduction in dietary restrictions. The cost/benefit ratio of such treatment for selected cases of food allergy remains to be evaluated.

Debates in Allergy Medicine: Does oral immunotherapy shorten the duration of milk and egg allergy? The pro argument.

The development of oral tolerance or food allergy is an active process, related to dynamic interactions between host immune cells, microbiome, dietary factors, and food allergens. Oral tolerance is the default immune response in the gut. A food allergy occurs when this process fails and a pathologic Th2 response is activated. Oral food immunotherapy (OIT) aims to restore immune tolerance in food-allergic individuals. The stimulation of Tregs production seems to represent a crucial step in inducing long-term tolerance, but other mechanisms (e.g., the suppression of mast cell and basophil reactivity, changes in allergen-specific cells with regulatory markers) are involved. Several studies reported the efficacy of OIT in terms of "sustained unresponsiveness" (SU), an operational definition of immune tolerance. In successfully treated subjects, the ability to pass an oral food challenge 2 to 8 weeks after stopping the food allergen exposure seems to be conditioned by the treatment starting age, frequency, amount or type of food consumed, and by the duration of the maintenance phase. Based on the available data, the percentage of milk- and egg-allergic subjects achieving sustained unresponsiveness after an OIT ranges from 21% to 58,3%. A comprehensive understanding of mechanisms underlying the induction of oral tolerance with OIT, or natural tolerance to food allergens in healthy individuals, could potentially lead to advances in development of better treatment options for food allergic patients.

Food protein-induced enterocolitis syndrome: a review of the new guidelines.

Food protein-induced enterocolitis syndrome (FPIES) is a non IgE-mediated gastrointestinal food allergy that presents with delayed vomiting after ingestion primarily in infants. While the pathophysiology of FPIES is poorly understood, the clinical presentation of acute FPEIS reactions has been well characterized. The first International Consensus Guidelines for the Diagnosis and Management of Food Protein-induced Enterocolitis Syndrome were published in 2017 and reviewed epidemiology, clinical presentation, and prognosis of acute and chronic FPIES. The workgroup outlined clinical phenotypes, proposed diagnostic criteria, and made recommendations on management. This article summarizes the guidelines and adds recent updates. FPIES is gaining recognition, however there continues to be delays in diagnosis and misdiagnosis due to overlap of symptoms with over conditions, lack of a diagnostic test, and because some of the common trigger foods are not thought of as allergenic. More research into disease mechanisms and factors influencing differences between populations is needed.

How to actively treat food allergy.

PURPOSE OF REVIEW: In the last years, food allergy treatment is moving away from food avoidance to interventional treatments. We review here the recent developments on immunotherapy with food allergens. RECENT FINDINGS: Oral immunotherapy remains the best studied form of food immunotherapy. In 2017, further evidence has been added to its efficacy. Its mechanisms of action are under scrutiny. To reduce its side effects, studies have been dedicated to the simultaneous use of biologics, in particular omalizumab. Among the other forms of food immunotherapy that are being developed, the epicutaneous application of food allergens is promising. SUMMARY: The immunologic trajectories of the development of food tolerance may be intercepted by different forms of food immunotherapy. Research efforts aim to make these therapies feasible at the clinical level.

How to predict and improve prognosis of food allergy.

PURPOSE OF REVIEW: The prevalence of food allergy is increasing. More children are being diagnosed with food allergies, and it is taking longer to outgrow them, among those who develop tolerance. The aim of this review is to draw the profile of the persistent food allergic, so that prevention strategies can be developed and active treatment set up. RECENT FINDINGS: Many determinants are involved in food allergy prognosis: ethnicity and sex, type of food, innate immune system, eliciting dose, sensitization status and other biomarkers determination, gut microbiome composition, and the presence of comorbidities. Once identified, a persistent food allergy could be conveyed to active treatments, such as oral immunotherapy or the use of biologics, always taking into account their experimental nature. SUMMARY: A better understanding of prognostic factors and phenotypes of food allergy is crucial in decision-making when it comes to food allergy prevention and management. A good classification of the allergic patient allows to determine the degree of exclusion diets and the timing of the reintroduction of avoided food when possible. In the cases of persistent and severe food allergy, many promising interventions are emerging which could improve prognosis and quality of care.

Use of biologics in severe food allergies.

PURPOSE OF REVIEW: Severe cases of food allergy account for the majority of the burden in terms of risks, quality of life, and resource expenditure. The traditional approach to these forms has been strict avoidance. More recently, Oral ImmunoTherapy (OIT) has gained a role in their management. However, in severe food allergies OIT is often infeasible. RECENT FINDINGS: Case reports, observational, and prospective studies have recently proposed different approaches to severe food allergy. The majority of them include the use of biologics. Omalizumab has been the most studied drug for severe food allergies, and its role as adjuvant treatment to OIT is well established. Interest has been raised on other biologics, as dupilumab, reslizumab, and mepolizumab. Toll-like receptor agonists, and gene therapy using adeno-associated virus coding for Omalizumab are promising alternatives. SUMMARY: The recent studies are deeply influencing the clinical practice. We review the modifications of the clinical approach to severe food allergies so far available. We indicate the possible evolutions of treatment with biologics in severe food allergies.

Anaphylactic shock with methylprednisolone sodium succinate in a child with short bowel syndrome and cow's milk allergy.

BACKGROUND: Medications with methyl-prednisolone sodium succinate containing lactose, which potentially contains traces of cow's milk proteins (CMP), could cause allergic reactions or compromise treatment of acute allergic reactions in sensitized patients. CASE PRESENTATION: We describe the unusual case of a one-year-old child affected by short bowel syndrome and history of severe cow's milk allergy (CMA) and anaphylactic reaction due to intravenous administration of methyl-prednisolone sodium succinate (Solu-Medrol 40 mg, Pfizer). He was admitted to our hospital for severe respiratory failure and was initially treated with methyl-prednisolone (Urbason 40 mg, Sanofi Aventis), then with methyl-prednisolone sodium succinate (Solu-Medrol 40 mg, Pfizer). After the intravenous administration of second steroid, immediate anaphylaxis was recorded and treatment was stopped. Antihistamine and epinephrine were required and symptom resolution occurred. CONCLUSION: Children who are highly sensitive to milk may have severe allergic reactions also after exposure to CMP through a different administration route than the oral one. Patients who have food allergies need to pay particular attention to the prescription of drugs and their formulation.