Pathophysiological Roles of Neuro-Immune Interactions between Enteric Neurons and Mucosal Mast Cells in the Gut of Food Allergy Mice.

Recently, the involvement of the nervous system in the pathology of allergic diseases has attracted increasing interest. However, the precise pathophysiological role of enteric neurons in food allergies has not been elucidated. We report the presence of functional high-affinity IgE receptors (FcεRIs) in enteric neurons. FcεRI immunoreactivities were observed in approximately 70% of cholinergic myenteric neurons from choline acetyltransferase-eGFP mice. Furthermore, stimulation by IgE-antigen elevated intracellular Ca2+ concentration in isolated myenteric neurons from normal mice, suggesting that FcεRIs are capable of activating myenteric neurons. Additionally, the morphological investigation revealed that the majority of mucosal mast cells were in close proximity to enteric nerve fibers in the colonic mucosa of food allergy mice. Next, using a newly developed coculture system of isolated myenteric neurons and mucosal-type bone-marrow-derived mast cells (mBMMCs) with a calcium imaging system, we demonstrated that the stimulation of isolated myenteric neurons by veratridine caused the activation of mBMMCs, which was suppressed by the adenosine A3 receptor antagonist MRE 3008F20. Moreover, the expression of the adenosine A3 receptor gene was detected in mBMMCs. Therefore, in conclusion, it is suggested that, through interaction with mucosal mast cells, IgE-antigen-activated myenteric neurons play a pathological role in further exacerbating the pathology of food allergy.

Cross-sectional imaging of intestinal barrier dysfunction by confocal laser endomicroscopy can identify patients with food allergy in vivo with high sensitivity.

Food allergy (FA) affects approximately 3 to 4% of the adult population in westernized countries. Suspected FA is even more prevalent and requires extensive diagnostic work-up. Within this study, we evaluated whether assessment of the integrity of the epithelial barrier by confocal laser endomicroscopy (CLE) during colonoscopy can be used as a screening tool to identify patients with FA. 60 patients with suspected FA were prospectively included. Serology with total and food-specific IgE, anti-tissue transglutaminase, skin prick testing, food intolerance tests, food intake registration and assessment of clinical complaints were performed. During colonocopy, standardized CLE was performed in the terminal ileum and at two colorectal sites. Analysis of CLE images included functional (i.e. presence of epithelial barrier dysfunction) and quantitative parameters of intestinal architecture. 27 of 60 patients (45%) were diagnosed with FA. Barrier dysfunction was analyzed on 65.837 ileal and on 93.251 colonic images. 96% of patients with FA exhibited functional and structural barrier defects while barrier dysfunction was found in only 33% of patients without FA (p < 0.0001). Visualizing barrier dysfunction with CLE for in vivo diagnosis of FA had a sensitivity and specificity of 96% and 67%, respectively, with a positive and negative prediction of 70% and 96%, respectively. Parameters intrinsic to the crypt architecture including crypt diameter, intercrypt distance, crypt lumen diameter and colonic vasculature were not different between patients with and without FA. CLE-based imaging of the intestinal barrier during colonoscopy might help in stratifying patients with suspected FA for further diagnostic work-up.

Production of allergen-specific immunotherapeutic agents for the treatment of food allergy.

Allergen-specific immunotherapy (IT) is emerging as a viable avenue for the treatment of food allergies. Clinical trials currently investigate raw or slightly processed foods as therapeutic agents, as trials using food-grade agents can be performed without the strict regulations to which conventional drugs are subjected. However, this limits the ability of standardization and may affect clinical trial outcomes and reproducibility. Herein, we provide an overview of methods used in the production of immunotherapeutic agents for the treatment of food allergies, including processed foods, allergen extracts, recombinant allergens, and synthetic peptides, as well as the physical and chemical processes for the reduction of protein allergenicity. Commercial interests currently favor producing standardized drug-grade allergen extracts for therapeutic use, and clinical trials are ongoing. In the near future, recombinant production could replace purification strategies since it allows the manufacturing of pure, native allergens or sequence-modified allergens with reduced allergenicity. A recurring issue within this field is the inadequate reporting of production procedures, quality control, product physicochemical characteristics, allergenicity, and immunological properties. This information is of vital importance in assessing therapeutic standardization and clinical safety profile, which are central parameters for the development of future therapeutic agents.

Food Allergies and Ageing.

All over the world, there is an increase in the overall survival of the population and the number of elderly people. The incidence of allergic reactions is also rising worldwide. Until recently, allergies, and in particular food allergies (FAs), was regarded as a pediatric problem, since some of them start in early childhood and may spontaneously disappear in adulthood. It is being discovered that, on the contrary, these problems are increasingly affecting even the elderly. Along with other diseases that are considered characteristics of advanced age, such as cardiovascular, dysmetabolic, autoimmune, neurodegenerative, and oncological diseases, even FAs are increasingly frequent in the elderly. An FA is a pleiomorphic and multifactorial disease, characterized by an abnormal immune response and an impaired gut barrier function. The elderly exhibit distinct FA phenotypes, and diagnosis is difficult due to frequent co-morbidities and uncertainty in the interpretation of in vitro and in vivo tests. Several factors render the elderly susceptible to FAs, including the physiological changes of aging, a decline in gut barrier function, the skewing of adaptive immunity to a Th2 response, dysregulation of innate immune cells, and age-related changes of gut microbiota. Aging is accompanied by a progressive remodeling of immune system functions, leading to an increased pro-inflammatory status where type 1 cytokines are quantitatively dominant. However, serum Immunoglobulin E (IgE) levels and T helper type 2 (Th2 cytokine production have also been found to be increased in the elderly, suggesting that the type 2 cytokine pattern is not necessarily defective in older age. Dysfunctional dendritic cells in the gut, defects in secretory IgA, and decreased T regulatory function in the elderly also play important roles in FA development. We address herein the main immunologic aspects of aging according to the presence of FAs.

Eosinophilic esophagitis in children: current knowledge to open new horizons.

Eosinophilic Esophagitis (EoE) is a chronic immune/antigen-mediated condition which is also driven by genetic and environmental factors. It has been deeply investigated over the last years and its incidence is widely increasing in childhood. Although atopic diseases are closely linked with EoE, it does not recognize a classical IgE-mediate immune pathogenesis but it is rather a T helper type 2 inflammatory process. Familial clustering supports genetic predisposition in EoE and recent advances in understanding the genetic basis for EoE may eventually translate into targeted management of the disease. EoE diagnosis is based on clinical symptoms, micro, and macroscopic findings along with exclusion of gastroesophageal reflux disease (GERD) evidence. Management of the disease encompasses both dietary and pharmacological solutions that need to be specifically targeted on patients' history, clinical symptoms, and diagnostic evaluations. New therapies, currently not available in children, may represent the basis for future therapeutic options in the next years.

Eosinophilic esophagitis: Pathophysiology, diagnosis, and management.

Eosinophilic esophagitis (EoE) is a multifactorial esophageal inflammation, with a genetic predisposition, which combines a deficient esophageal mucosal barrier, an abnormal immune reaction to environmental allergens mediated by Th2 interleukins, immediate esophageal lesions and dysmotility, with secondary remodeling and fibrosis. Symptoms include reflux, abdominal pain, and food impaction, with a variation according to age. Fibroscopy shows major and minor endoscopic and histologic criteria, with a mucosal count≥15 eosinophils/high power field (Eo/hpf). A new entity has been defined, where gastroesophageal reflux disease (GERD) and EoE share responsibility: the PPIs-sensitive form of EoE (PPI-REE). Children with fibroscopy showing≥15 Eo/hpf need a second endoscopy following 8 weeks of PPI treatment. EoE has a strong association with other atopic disorders. Allergy testing (specific IgE blood test and skin prick tests [SPTs]) identifies patients at risk of anaphylaxis (14.8% of cases). The dietary therapy is based on a 4- to 12-week elimination test followed by endoscopy to check the disappearance of eosinophilic infiltration. The "dietary approaches are the amino acid-based formula, the allergy testing-based targeted diet, and the six-food elimination diet (empirical elimination of milk, wheat, soy, eggs, peanut/nuts, and fish/seafood). A recent first-line trial elimination of milk has been suggested, with wheat as a second elimination, if necessary. Dietary therapy allows remission and catch-up growth in 65% of cases. Swallowed topical steroids (budesonide in viscous gel or fluticasone propionate for nebulization) are an alternative, for which efficacy varies according to clinical and/or histological criteria and with relapses occurring at dosage tapering. Their use may be restricted by side effects, such as oral and/or esophageal candidiasis. The impact on long-term bone health and growth is unknown. Maintenance therapy is not standardized and is team-dependent, combining or not elimination diets and long-term steroids. The long-term risk of EoE is esophageal stenosis (25%) and endoscopic dilation may be repeated. Biotherapies have shown isolated histological improvement without significant clinical efficacy.

The Effect of Digestion and Digestibility on Allergenicity of Food.

Food allergy prevalence numbers are still on the rise. Apart from environmental influences, dietary habits, food availability and life-style factors, medication could also play a role. For immune tolerance of food, several contributing factors ensure that dietary compounds are immunologically ignored and serve only as source for energy and nutrient supply. Functional digestion along the gastrointestinal tract is essential for the molecular breakdown and a prerequisite for appropriate uptake in the intestine. Digestion and digestibility of carbohydrates and proteins thus critically affect the risk of food allergy development. In this review, we highlight the influence of amylases, gastric acid- and trypsin-inhibitors, as well as of food processing in the context of food allergenicity.

Eosinophilic Esophagitis.

Eosinophilic esophagitis (EoE) is a chronic allergic inflammatory disease of the esophagus that effects children and adults. Typical symptoms of EoE typically involve failure to thrive and vomiting in small children, and dysphagia and food impaction in adolescents and adults. However, throat clearing, choking, gagging, and hoarseness have also been observed and these issues often bring patients to first seek otolaryngology and pulmonary evaluation. Diagnosis is only made by esophogastroduodenoscopy with biopsy, so clinicians must have a low threshold for considering eosinophilic esophagitis even in the absence of frank gastrointestinal symptoms.

Food allergy.

Food allergies manifest in a variety of clinical conditions within the gastrointestinal tract, skin and lungs, with the most dramatic and sometimes fatal manifestation being anaphylactic shock. Major progress has been made in basic, translational and clinical research, leading to a better understanding of the underlying immunological mechanisms that lead to the breakdown of clinical and immunological tolerance against food antigens, which can result in either immunoglobulin E (IgE)-mediated reactions or non-IgE-mediated reactions. Lifestyle factors, dietary habits and maternal-neonatal interactions play a pivotal part in triggering the onset of food allergies, including qualitative and quantitative composition of the microbiota. These factors seem to have the greatest influence early in life, an observation that has led to the generation of hypotheses to explain the food allergy epidemic, including the dual-allergen exposure hypothesis. These hypotheses have fuelled research in preventive strategies that seek to establish desensitization to allergens and/or tolerance to allergens in affected individuals. Allergen-nonspecific therapeutic strategies have also been investigated in a number of clinical trials, which will eventually improve the treatment options for patients with food allergy.

Irritable Bowel Syndrome: Epidemiology, Pathophysiology, Diagnosis, and Treatment.

Irritable bowel syndrome is a common medical condition that significantly alters patient quality of life and presents a series of diagnostic and treatment challenges to the treating provider. This article provides an updated and straightforward overview of the disease, its pathophysiology, diagnosis, and treatment options.

Celiac Disease and Gluten Sensitivity.

Celiac disease is an immune-mediated enteropathy triggered by gluten that affects genetically predisposed individuals, typically causing intestinal symptoms and malabsorption. Diagnosis requires stepwise evaluation with anti-tissue transglutaminase IgA and histologic analysis of the small bowel. Strict adherence to a gluten-free diet is the primary treatment. Patients with symptoms thought to be related to gluten but without evidence of celiac disease are difficult to diagnose and treat. Consider first advising general nutritional improvements. If symptoms persist, involve a trained dietitian for restrictive diets and consider evaluation for small intestinal bacterial overgrowth or other treatments for irritable bowel syndrome.

Atopic dermatitis progression: evaluating intervention strategies.

Several risk factors have been identified that appear to be consistently and strongly associated with the development of atopic dermatitis (AD): a family history of atopy, an inherited genetic predisposition, and active and passive exposure to tobacco smoke. Recent studies also have demonstrated that a simple intervention from birth-the daily application of an emollient moisturizer-seems to protect susceptible infants from the development of AD.

Increasing Comorbidities Suggest that Atopic Dermatitis Is a Systemic Disorder.

Atopic dermatitis comorbidities extend well beyond the march to allergic conditions (food allergy, asthma, allergic rhinitis, allergic conjunctivitis, and eosinophilic esophagitis), suggesting both cutaneous and systemic immune activation. In reviewing atopic dermatitis comorbidities, Councilors of the International Eczema Council found a strong pattern of immune activation in peripheral blood and the propensity to both skin and systemic infections. Associations with cardiovascular, neuropsychiatric, and malignant diseases were increasingly reported, but confirmation of their link with atopic dermatitis requires longitudinal studies. Given the possibility of atopic dermatitis-related systemic immune activation, future investigations of new interventions should concurrently examine the impact on these comorbidities.

Evaluation of basophil activation test in suspected food hypersensitivity.

BACKGROUND: Food hypersensitivity is characterized by a wide range of symptoms. The relationship between symptoms and food is more frequently suspected than objectively proven. Basophil activation test (BAT) is based on the evaluation of activation markers on blood basophils in vitro stimulated with drugs or allergens. The aim of the study was to evaluate the usefulness of BAT when introduced in the routine work-up of suspected food hypersensitivity. METHODS: BAT was requested in subjects with food adverse reactions when a discrepancy existed among history and skin prick test (SPT) and/or specific IgE. Data from 150 subjects were analysed using CD63 as basophil activation marker. Thirty controls were evaluated for cut-offs. Immunoblots was performed with the sera of representative subjects positive for BAT and negative for SPT and sIgE. RESULTS: 1,024 BAT were carried out, the agreement (positive/positive and negative/negative) was 78.5% for BAT vs. SPT and 78.3% for BAT vs. IgE. Atopic patients, but not atopic controls, more frequently had a positive BAT than non-atopic patients (P < 0.0001). Among subjects with positive BAT, those with negative sIgE had lower total IgE, P = 0.001. Nearly 23.3% of all subjects had positive BAT (for at least one tested food) and both negative sIgE and SPT. Immunoblots revealed the presence of sIgE for the tested foods in representative patients with positive BAT, negative SPT and sIgE. CONCLUSION: Introduction of BAT in routine of food hypersensitivity, limited to subjects with a discrepancy between history and traditional tests, might be useful particularly when total IgE are low. © 2015 International Clinical Cytometry Society.

Severe forms of food allergy / Formas graves de alergia alimentar

Abstract Objectives: To guide the diagnostic and therapeutic management of severe forms of food allergy. Data sources: Search in the Medline database using the terms "severe food allergy," "anaphylaxis and food allergy," "generalized urticaria and food allergy," and "food protein-induced enterocolitis syndrome" in the last ten years, searching in the title, abstract, or keyword fields. Summary of data: Food allergy can be serious and life-threatening. Milk, eggs, peanuts, nuts, walnuts, wheat, sesame seeds, shrimp, fish, and fruit can precipitate allergic emergencies. The severity of reactions will depend on associated cofactors such as age, drug use at the onset of the reaction, history and persistence of asthma and/or severe allergic rhinitis, history of previous anaphylaxis, exercise, and associated diseases. For generalized urticaria and anaphylaxis, intramuscular epinephrine is the first and fundamental treatment line. For the treatment in acute phase of food-induced enterocolitis syndrome in the emergency setting, prompt hydroelectrolytic replacement, administration of methylprednisolone and ondansetron IV are necessary. It is important to recommend to the patient with food allergy to maintain the exclusion diet, seek specialized follow-up and, in those who have anaphylaxis, to emphasize the need to carry epinephrine. Conclusion: Severe food allergy may occur in the form of anaphylaxis and food-protein-induced enterocolitis syndrome, which are increasingly observed in the pediatric emergency room; hence, pediatricians must be alert so they can provide the immediate diagnosis and treatment.

Resumo Objetivos: Abordar o manejo diagnóstico e terapêutico das formas graves de alergia alimentar. Fontes dos dados: Busca ativa na base de dados Medline dos termos severe food allergies, anaphylaxis and food allergy e food protein-induced enterocolitis nos últimos dez anos e com busca nos campos título, resumo ou palavra-chave. Síntese dos dados: A alergia alimentar pode ser grave e ameaçadora à vida. Leite, ovo, amendoim, castanha, noz, trigo, gergelim, crustáceo, peixe e frutas podem precipitar emergências alérgicas. A gravidade das reações vai depender de fatores associados, tais como idade, uso de medicamentos no início da reação, persistência de asma e/ou rinite alérgica grave, história de prévia anafilaxia, exercício e doenças intercorrentes. Para anafilaxia, a adrenalina intramuscular é uma indicação bem estabelecida. Para o tratamento da síndrome da enterocolite induzida pela proteína alimentar na fase aguda no setor de emergência, fazem-se necessárias a pronta reposição hidroeletrolítica e a administração de metilprednisolona e odansetrona IV. Importante recomendar ao paciente com o diagnóstico de alergia alimentar grave que mantenha a dieta de exclusão, procure acompanhamento especializado e, naqueles que apresentaram anafilaxia, enfatizar a necessidade de portar adrenalina. Conclusão: Alergia alimentar grave pode se manifestar como anafilaxia ou síndrome da enterocolite induzida por proteína alimentar em fase aguda, as quais, por serem condições cada vez mais presentes e reconhecidas no setor de emergência pediátrica, demandam diagnóstico e tratamento imediatos.

Nuclear transit study in children with chronic faecal soiling after Hirschsprung disease (HSCR) surgery has revealed a group with rapid proximal colonic treatment and possible adverse reactions to food.

BACKGROUND/PURPOSE: Long-term problems with faecal incontinence occur in up to 50 % of patients after pull-through for Hirschsprung disease (HSCR). The cause often remains unknown, leading to empirical treatments. Using nuclear transit study, we found some patients surprisingly had rapid proximal colonic transit, suspicious of occult diarrhoea. We aimed to assess whether these patients had unrecognized adverse reactions to food. METHODS: Patients (n = 10, all males, 9.6 year; 4.25-15.5 years) with persistent faecal incontinence following pull-through for HSCR referred to the senior author and after exclusion of anatomical defects, underwent nuclear transit studies. Most (8) subsequently underwent breath hydrogen tests for sugar malabsorption and were tested for adverse reactions to food. Exclusion diets for protein allergens, lactose or fructose were then trialed. RESULTS: Of the 10 patients with rapid intestinal transit proven on nuclear transit study, breath hydrogen tests for fructose and/or lactose malabsorption were done in 8, and were positive in 7/8 patients. Exclusion diets contributed to either resolution or improvement in faecal incontinence in 9/10 patients. CONCLUSIONS: Rapid transit in the proximal, ganglionated colon may be present in children with faecal incontinence following pull-through for HSCR, possibly secondary to adverse reactions to food. This study suggests that children with post-operative soiling may benefit from a transit study and hydrogen breath tests to diagnose adverse reactions to food caused by sugar malabsorption.

Anaphylaxis Imaging: Non-Invasive Measurement of Surface Body Temperature and Physical Activity in Small Animals.

In highly sensitized patients, the encounter with a specific allergen from food, insect stings or medications may rapidly induce systemic anaphylaxis with potentially lethal symptoms. Countless animal models of anaphylaxis, most often in BALB/c mice, were established to understand the pathophysiology and to prove the safety of different treatments. The most common symptoms during anaphylactic shock are drop of body temperature and reduced physical activity. To refine, improve and objectify the currently applied manual monitoring methods, we developed an imaging method for the automated, non-invasive measurement of the whole-body surface temperature and, at the same time, of the horizontal and vertical movement activity of small animals. We tested the anaphylaxis imaging in three in vivo allergy mouse models for i) milk allergy, ii) peanut allergy and iii) egg allergy. These proof-of-principle experiments suggest that the imaging technology represents a reliable non-invasive method for the objective monitoring of small animals during anaphylaxis over time. We propose that the method will be useful for monitoring diseases associated with both, changes in body temperature and in physical behaviour.

Sensibilidad no celíaca al gluten: Una patología más que responde al gluten / Non-celiac gluten sensitivity: Another condition that responds to gluten

Remission of gastrointestinal and general symptoms after gluten withdrawal has been described in some non-celiac individuals for nearly 30 years. Only recently, efforts have been made to define this entity, now referred to as "non- celiac gluten sensitivity". It includes patients that clinically respond to gluten free diet without exhibiting allergic or autoimmune features to explain such response. Wheat allergy, celiac disease, irritable bowel syndrome and symptoms induced by high FODMAPs (Fermentable, Oligo-, Di-, Mono-saccharides And Polyols) consumption are the main differential diagnoses. The relationship with neuropsychiatric disorders such as schizophrenia and autism has not been demonstrated, but currently it gives ground to great hope in families with affected children. Epidemiology of non-celiac gluten sensitivity is not clear. It is described as more common among women and less common in children. Genetic and immune factors, changes in intestinal microbiota and non-gluten components present in wheat grains are main factors postulated in the pathogenesis of this condition. To date, there are no specific biomarkers for non-celiac gluten sensitivity and diagnosis is reached by excluding other causes of disease. A trial with gluten-free diet and subsequent gluten challenge is the methodology most frequently used to confirm diagnosis.

Oral allergy syndrome.

PURPOSE OF REVIEW: Oral allergy syndrome (OAS) is common in patients with allergic rhinoconjunctivitis. OAS may be less recognized in clinical practice leading to unclear diagnosis and treatment plans. Many aspects of OAS remain poorly understood, including a lack of a standard definition, limits in diagnostic tests, and complicated pathophysiology with a multitude of cross-reactivities. Understanding the range of mild-to-severe reactions will assist providers in developing the best approaches for diagnosis and management of patients with OAS. RECENT FINDINGS: A standardized definition of OAS does not exist in the current literature, which can make diagnosis and treatment of OAS difficult. Multiple studies have attempted to better define parameters for diagnosis and treatment; however, the complexity of the cross-reactivity between allergens makes this task difficult. Studies have investigated members in each of the protein families implicated in OAS, but largely without identification of broad candidate markers. Those candidate markers that have been established are typically too specific, which limits generalization. SUMMARY: This review will address current OAS definitions, pathophysiology, diagnosis, and available treatments. Current literature largely focuses on attempts to identify cross-reactivities and markers that may be useful in diagnosis and treatment of patients with OAS.