Pollen-food allergy syndrome is a common allergic comorbidity in adults with eosinophilic esophagitis

Triggers for eosinophilic esophagitis (EoE): The intersection of food allergy and EoE

Eosinophilic esophagitis and IgE-mediated food allergy are both food-triggered diseases that are increasing in prevalence. They share many clinical links, including significant comorbidity and similar food triggers, and as atopic diseases, they likely share upstream mechanisms related to barrier function and signals leading to TH2 skewing. In this review, we focus on links between eosinophilic esophagitis and IgE-mediated food allergy with an emphasis on what insights may be derived from overlapping food triggers and immune phenotypes. Through further investigation of these connections, we may be able to better understand not only IgE-mediated food allergy and eosinophilic esophagitis but also general atopic response to food proteins and evolution of allergic response to food.

Epithelial overexpression of IL-33 induces eosinophilic esophagitis dependent on IL-13

BACKGROUND

Eosinophilic esophagitis (EoE) is an increasingly common inflammatory condition of the esophagus; however, the underlying immunologic mechanisms remain poorly understood. The epithelium-derived cytokine IL-33 is associated with type 2 immune responses and elevated in esophageal biopsy specimens from patients with EoE.

OBJECTIVE

We hypothesized that overexpression of IL-33 by the esophageal epithelium would promote the immunopathology of EoE.

METHODS

We evaluated the functional consequences of esophageal epithelial overexpression of a secreted and active form of IL-33 in a novel transgenic mouse, EoE33. EoE33 mice were analyzed for clinical and immunologic phenotypes. Esophageal contractility was assessed. Epithelial cytokine responses were analyzed in three-dimensional organoids. EoE33 phenotypes were further characterized in ST2-/-, eosinophil-deficient, and IL-13-/- mice. Finally, EoE33 mice were treated with dexamethasone.

RESULTS

EoE33 mice displayed ST2-dependent, EoE-like pathology and failed to thrive. Esophageal tissue remodeling and inflammation included basal zone hyperplasia, eosinophilia, mast cells, and TH2 cells. Marked increases in levels of type 2 cytokines, including IL-13, and molecules associated with immune responses and tissue remodeling were observed. Esophageal organoids suggested reactive epithelial changes. Genetic deletion of IL-13 in EoE33 mice abrogated pathologic changes in vivo. EoE33 mice were responsive to steroids.

CONCLUSIONS

IL-33 overexpression by the esophageal epithelium generated immunopathology and clinical phenotypes resembling human EoE. IL-33 may play a pivotal role in the etiology of EoE by activating the IL-13 pathway. EoE33 mice are a robust experimental platform for mechanistic investigation and translational discovery.

Diagnosis and Management of Pollen Food Allergy Syndrome to Nuts

Oral allergy syndrome or pollen food allergy syndrome (PFAS) represents a common clinical conundrum when the reported trigger food is a tree nut (usually almond or hazelnut) or peanut. The PFAS may give rise to uncertainty about the potential severity of the future reactions, indications for prescribing epinephrine, and the extent of the necessary dietary avoidance. As a food allergy, secondary to cross-reactivity with airborne pollen, PFAS usually manifests toward the end of the first decade of life as contact urticaria of the oropharyngeal mucous membranes. Molecular allergology facilitates diagnosis and risk stratification by establishing the profile of sensitization. Exclusive sensitization to pathogenesis-related proteins family 10 (PR10) and profilins indicates that signs and symptoms are due to PFAS, whereas sensitization to seed storage proteins with or without sensitization to PR10 and profilins may indicate a more severe primary nut allergy phenotype. Management relies on avoidance of the specific nut trigger, advice on the likelihood of more severe local or systemic symptoms, and treatment of reactions according to the severity. Future studies are needed to better delineate the risk of systemic reactions in individuals with nut PFAS and to establish the role of food or pollen allergen immunotherapy for the prevention or moderation of this condition.

Food-induced immediate response of the esophagus in pediatric eosinophilic esophagitis

BACKGROUND

Food-induced immediate response of the esophagus (FIRE) is a new phenomenon that has been described in eosinophilic esophagitis (EoE) patients. It is suspected when unpleasant symptoms occur suddenly on contact of the triggering food with the esophageal surface and recur with repeated exposures. It can often be mistaken for pollen-food allergy syndrome (PFAS) and solid food dysphagia. Data on FIRE is limited to one survey study and case reports, and there are no screening studies conducted on either adults or children with EoE. In this study, we aimed to screen children aged ≥7 years old with EoE for FIRE.

METHODS

Demographic data were collected from medical records. A questionnaire about FIRE was applied to all participants. Skin prick tests were done on suspected patients to identify the triggering foods. FIRE is defined as suitable clinical symptoms with suspected food allergen exposure.

RESULTS

A total of 78 patients (74.4% male, median age: 13.5 years) were included. Unpleasant and recurrent symptoms distinct from dysphagia with specific foods were reported in 16.7% of the patients, all of whom had concomitant allergic rhinitis (AR). The symptoms described by almost all patients were oropharyngeal itching and tingling (PFAS: 15.3%) excluding only one patient reporting retrosternal narrowing and pressure after specific food consumption (FIRE: 1.2%).

CONCLUSIONS

Although definitive conclusions regarding the true prevalence of FIRE cannot be made, it does not seem to be common as PFAS. However, it deserves questioning particularly in the presence of concurrent AR and/or PFAS in children with EoE.

Food-Specific IgG4 Is Elevated Throughout the Upper Gastrointestinal Tract in Eosinophilic Esophagitis

BACKGROUND

Food-specific immunoglobulin G4 (FS-IgG4) is associated with eosinophilic esophagitis (EoE); however, it is not clear whether production is limited to the esophagus.

AIMS

To assess FS-IgG4 levels in the upper gastrointestinal tract and plasma and compare these with endoscopic disease severity, tissue eosinophil counts, and patient-reported symptoms.

METHODS

We examined prospectively banked plasma, throat swabs, and upper gastrointestinal biopsies (esophagus, gastric antrum, and duodenum) from control (n = 15), active EoE (n = 24), and inactive EoE (n = 8) subjects undergoing upper endoscopy. Patient-reported symptoms were assessed using the EoE symptom activity index (EEsAI). Endoscopic findings were evaluated using the EoE endoscopic reference score (EREFS). Peak eosinophils per high-power field (eos/hpf) were assessed from esophageal biopsies. Biopsy homogenates and throat swabs were normalized for protein content and assessed for FS-IgG4 to milk, wheat, and egg.

RESULTS

Median FS-IgG4 for milk and wheat was significantly increased in the plasma, throat swabs, esophagus, stomach, and duodenum of active EoE subjects compared to controls. No significant differences for milk- or wheat-IgG4 were observed between active and inactive EoE subjects. Among the gastrointestinal sites sampled, FS-IgG4 levels were highest in the esophagus. Esophageal FS-IgG4 for all foods correlated significantly across all sites sampled (r ≥ 0.59, p < 0.05). Among subjects with EoE, esophageal FS-IgG4 correlated significantly with peak eos/hpf (milk and wheat) and total EREFS (milk). EEsAI scores and esophageal FS-IgG4 levels did not correlate.

CONCLUSIONS

Milk and wheat FS-IgG4 levels are elevated in plasma and throughout the upper gastrointestinal tract in EoE subjects and correlate with endoscopic findings and esophageal eosinophilia.

Food Allergy Characteristics Associated With Coexisting Eosinophilic Esophagitis in FARE Registry Participants

BACKGROUND

Eosinophilic esophagitis (EoE) can coexist in individuals with food allergy.

OBJECTIVE

To evaluate the characteristics of food-allergic patients with and without coexisting EoE using a large food allergy patient registry.

METHODS

Data were derived from 2 Food Allergy Research & Education, Inc, Patient Registry surveys. A series of multivariable regression models were used to evaluate associations between demographic, comorbidity, and food allergy characteristics and the likelihood of reporting EoE.

RESULTS

Five percent (n = 309) of registry participants (n = 6074; ages <1 year->80 years, mean, 20.20 ± 15.37 years) reported having EoE. The odds of having EoE were significantly greater in male participants (adjusted odds ratio [aOR], 1.3; 95% CI, 1.04-1.72) and those with comorbid asthma (aOR, 2.0; 95% CI, 1.55-2.49), allergic rhinitis (aOR, 1.8; 95% CI, 1.37-2.22), oral allergy syndrome (aOR, 2.8; 95% CI, 2.09-3.70), food protein-induced enterocolitis syndrome (aOR, 2.5; 95% CI, 1.34-4.84), and hyper-IgE syndrome (aOR, 7.6; 95% CI, 2.93-19.92), though not atopic dermatitis (aOR, 1.3; 95% CI, 0.99-1.59), when adjusting for demographics (sex, age, race, ethnicity, and geographic location). Those with a greater number of food allergies (aOR, 1.3; 95% CI, 1.23-1.32), more frequent food-related allergic reactions (aOR, 1.2; 95% CI, 1.11-1.24), previous anaphylaxis (aOR, 1.5; 95% CI, 1.15-1.83), and health care utilization for food-related allergic reactions (aOR, 1.3; 95% CI, 1.01-1.67)-specifically intensive care unit admission (aOR, 1.2; 95% CI, 1.07-1.33)-were more likely to have EoE after controlling for demographics. However, no significant difference in ever using epinephrine for food-related allergic reactions was detected.

CONCLUSIONS

These self-reported data showed that coexisting EoE is associated with an increased number of food allergies, food-related allergic reactions per year, and measures of reaction severity, calling attention to the likely increased health care needs of food-allergic patients with EoE.

Pediatric eosinophilic esophagitis outcomes vary with co-morbid eczema and pollen food syndrome

Background

Eosinophilic esophagitis (EoE) is a chronic immune-mediated inflammatory disease characterized by eosinophil inflammation of the esophagus. It has been described as a component of the Allergic March and is often seen with other atopic diseases. Some atopic diseases, including asthma, are known to be heterogenous with endotypes that guide treatment. Similarly, we propose that EoE is a heterogenous disease with varying phenotypes and endotypes that might impact response to therapy.

Methods

A single-center retrospective review of pediatric patients ≤18 years of age diagnosed with EoE was conducted. All gastrointestinal clinic visits and esophagogastroduodenoscopies (EGD) from disease presentation through the first three years after diagnosis were reviewed. Histologic remission rate and therapies utilized [proton pump inhibitor (PPI), topical steroid, dietary elimination] were assessed.

Results

One hundred and thirty-seven patients were included, 80% of whom had at least one concurrent atopic condition at diagnosis, with food allergies being the most common (57%) followed by eczema (34%), and asthma (29%). The remission rate of the overall cohort was 65%, and by concurrent allergy, comorbid pollen food syndrome and eczema had the highest remission rates at 100% and 81%, respectively followed by asthma (62%), food allergies (62%), seasonal allergic rhinitis (60%), and history of anaphylaxis (56%). Kaplan-Meier curves for each atopic condition show that patients with eczema and pollen food syndrome achieve histologic remission faster than those without. All treatment modalities were more successful in patients with eczema than those without, and PPI was most effective treatment at inducing remission.

Conclusions

In a real-world pediatric cohort, 80% of patients with EoE had an underlying atopic condition. Patients with eczema and pollen food syndrome had a swifter response and were more likely to achieve histologic remission than patients with other atopic conditions. This study suggests that EoE, like other allergic diseases, may have heterogenous phenotypes that could affect response to treatment. There is currently a knowledge gap in classifying EoE based on endotypes and phenotypes at diagnosis and correlating responses to various treatment modalities.

BSACI guideline for the diagnosis and management of pollen food syndrome in the UK

Pollen food syndrome (PFS) is a highly prevalent food allergy affecting pollen-sensitized children and adults. Sufferers experience allergic symptoms when consuming raw plant foods, due to the homology between the pollen allergens and unstable proteins in these foods. The triggers involved can vary depending on the pollen sensitization, which in turn is affected by geographical location. The British Society of Allergy and Clinical Immunology (BSACI) Standards of Care Committee (SOCC) identified a need to develop a guideline for the diagnosis and management of PFS in the United Kingdom (UK). Guidelines produced by the BSACI use either the GRADE or SIGN methodology; due to a lack of high-quality evidence these recommendations were formulated using the SIGN guidelines, which is acknowledged to be less robust than the GRADE approach. The correct diagnosis of PFS ensures the avoidance of a misdiagnosis of a primary peanut or tree nut allergy or confusion with another plant food allergy to non-specific lipid transfer proteins. The characteristic foods involved, and rapid-onset oropharyngeal symptoms, mean PFS can often be diagnosed from the clinical history alone. However, reactions involving tree nuts, peanuts and soya milk or severe/atypical reactions to fruits and vegetables may require additional diagnostic tests. Management is through the exclusion of known trigger foods, which may appear to be simple, but is highly problematic if coupled with a pre-existing food allergy or for individuals following a vegetarian/vegan diet. Immunotherapy to pollens is not an effective treatment for PFS, and although oral or sublingual immunotherapy to foods seems more promising, large, controlled studies are needed. The typically mild symptoms of PFS can lead to an erroneous perception that this condition is always easily managed, but severe reactions can occur, and anxiety about the onset of symptoms to new foods can have a profound effect on quality of life.

Diagnosing Pollen-food Allergy Syndrome Allergologically in a Patient with Suspected Eosinophilic Gastroenteritis

Pollen-food allergy syndrome (PFAS) consists of type I allergy to pollen and multiple food items that are cross-reactive to the pollen. PFAS typically occurs in the oral cavity and can co-occur with eosinophilic esophagitis. However, it is infrequently reported to present with symptoms of eosinophilic gastroenteritis (EGE), such as abdominal pain and eosinophilic infiltration of the gastrointestinal tract. We herein report a patient with a condition initially suspected of being EGE based on symptoms and pathological findings that was later diagnosed as PFAS associated with birch pollen. PFAS should be considered as a differential diagnosis in patients with EGE-like symptoms.

Safety of the standardized quality tree sublingual immunotherapy tablet: Pooled safety analysis of clinical trials

BACKGROUND

The standardized quality (SQ) tree sublingual immunotherapy (SLIT)-tablet has recently been approved for treatment of tree pollen allergy. Healthcare workers should be provided with detailed safety data for clinical use.

OBJECTIVE

To assess the tolerability and safety of the SQ tree SLIT-tablet (12 SQ-Bet) in adults and adolescents.

METHODS

Safety data were pooled from three double-blinded, randomized, placebo-controlled trials (2 phase-II/1 phase-III) including adults and adolescents 12-65 years with allergic rhinitis and/or conjunctivitis treated before and during one pollen season once-daily with 12 SQ-Bet (n = 471) or placebo (n = 458): EudraCT no: 2012-000031-59; NCT02481856; EudraCT 2015-004821-15.

RESULTS

The most frequently reported investigational medicinal product (IMP)-related AEs with 12 SQ-Bet were oral pruritis (39% of subjects) and throat irritation (29%). IMP-related AEs were mainly mild or moderate in severity, and the majority resolved without treatment and did not lead to treatment interruption/discontinuation. With 12 SQ-Bet, oral pruritus was more frequent among subjects with pollen food syndrome (PFS) (45%) than without PFS (29%). The 12 SQ-Bet did not seem to induce an increased risk of asthma: 7 events were reported in 7 subjects with 12 SQ-Bet and 11 in 10 subjects with placebo. No differences were seen in the risk of moderate-to-severe IMP-related AEs regardless of age, PFS status and asthma medical history.

CONCLUSIONS

The 12 SQ tree SLIT-tablet was well tolerated in tree pollen allergic subjects with no major safety concerns detected. This safety profile supports daily at-home sublingual administration once the first dose is tolerated when administered under medical supervision.

The Challenges of Managing Multiple Food Allergies and Consequent Food Aversions

The allergic march can often result in children with one food allergy phenotype developing other allergic manifestations as they grow older. In this grand round, we describe the case of a child with a diagnosis of eosinophilic esophagitis at an early age, who subsequently developed IgE-mediated allergy to milk and egg. Because of the onset of allergic rhinitis, an additional complication of the teenage years was the development of pollen food syndrome, which further affected the already complex dietary management. These multiple allergies had a consequent effect on nutritional status and provoked considerable psychosocial issues, which greatly affected the patient's relationship with food. This case illustrates that for complex patients, a cohesive approach and shared decision-making are essential for diagnosis and management. Working with the patient and also the whole family, and considering how best to support them, necessitates a flexible approach. Regular follow-up is important to address changing psychosocial and dietary needs and monitor the resolution of allergies and response to pharmacotherapy. Complex patients need the input of a comprehensive multidisciplinary team, with good access to dietetic and psychological support, to optimize quality of life for these individuals and their families.

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

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

Hospitalization trends and determinants of inpatient costs for eosinophilic esophagitis patients in the United States: results from the Nationwide Inpatient Sample analysis

BACKGROUND

Inpatient care for patients with eosinophilic esophagitis (EoE) is thought to be uncommon, there are few data on inpatient care costs for individuals with EoE. The purpose of this study was to assess trends in inpatient admissions for EoE and examine factors that drive hospitalization costs.

METHODS

We examined EoE hospitalizations using ICD-9/10 codes, from 2010-2016 in the National Inpatient Sample. We also identified the diagnosis-related group codes, current procedural terminology codes, and common symptom codes documented during admission. We conducted 2 main analyses, primary (all EoE-related hospitalizations) and secondary (hospitalization with a primary diagnosis for EoE), and a sensitivity analysis using only hospitalizations with the secondary diagnosis for EoE, to determine the trend and cost of EoE-related hospitalizations. We used univariate and multivariate models to evaluate the effect of factors that drive hospitalization on total costs.

RESULTS

Our primary analysis showed that an estimated total of 33,467 EoE-related hospitalizations occurred in the US between 2010 and 2016, representing approximately 13 per 100,000 hospitalizations in the US. The admission rate increased by approximately 70% from 2010-2016 (9.26 to 15.75 per 100,000 hospitalizations), while the total annual and mean inflation-adjusted per-patient costs for EoE-related admissions were $24 million per year and $5135 (standard deviation $153), respectively. Patients and hospital characteristics were independently associated with cost of hospitalization.

CONCLUSION

The rate of hospital admission for EoE has markedly increased in the US, as has the mean cost for EoE-related hospitalization, at a rate tenfold that of inflation from 2010-2016.

Rhinitis Phenotypes

Rhinitis is an umbrella term of a group of upper airway diseases with nasal symptoms and signs with different etiologies and various clinical features or traits. It can be classified into different "phenotypes," based on these observable traits. A proper differential diagnosis is necessary to adequately manage the disease. The objective of this review is to clarify the concept of rhinitis phenotypes while analyzing the clinical features and/or traits of each in order to determine a proper differential diagnosis and appropriate treatment.

Pediatric patient with eosinophilic esophagitis and pollen-food allergy syndrome

The incidence of eosinophilic esophagitis (EoE) and pollen-food allergy syndrome (PFAS) is increasing worldwide, and coexistence of these 2 diseases has been reported in adults. In children, however, these conditions have not been reported as comorbidities probably because sensitization to aeroallergens occurs at an older age. We report the case of a boy with EoE and PFAS. He had had intermittent vomiting since 2 years of age. At 7 years of age, he experienced an episode of itchiness of the lips and throat for the first time, followed by vomiting, immediately after ingesting some raw fruits. We diagnosed PFAS based on the skin prick test at 8 years of age and diagnosed EoE by esophagogastroduodenoscopy 11 months after the diagnose of PFAS. His digestive symptoms did not disappear despite eliminating the fruits responsible for PFAS, but esomeprazole improved his symptoms. The incidence of EoE and PFAS as comorbidities in children might increase in the future.

Eosinophilic esophagitis: comorbidities and atopic disease in Nevada

Eosinophilic esophagitis (EoE) is a rare, immune-mediated illness. We aimed to examine the comorbidities and sensitization patterns associated with an EoE diagnosis in Nevada. The study goal was two-fold: to determine the most common EoE comorbidities and sequela in the state of Nevada using healthcare utilization records across all settings and to determine the most common food and aeroallergens in histologically positive EoE pediatric patients using clinical sensitization data. Esophageal obstruction/stricture was the most frequently reported diagnosis in adults with EoE (29.5%). Among pediatrics, the highest ranking comorbidities included asthma (13.4%); diseases of the stomach, duodenum, and intestine (7.26%); allergies (7.01%); and gastroesophageal reflux disease (GERD) (3.69%). Additionally, the top sensitizations reported in histologically positive EoE patients were largely pollen related (82.9%). Atopic disease and specifically food allergens are commonly reported as comorbid conditions with EoE in the literature. However, our clinical pediatric data set from this study revealed that aeroallergen sensitizations far exceeded that of food allergens (82.9% aero-positive vs. 17.1% dood positive). The high presence of esophageal stricture/obstruction in adults could be indicative of late diagnosis; in addition, the aeroallergen sensitization in children could suggest different clinical management techniques necessary may be needed for this disease. Education among healthcare providers regarding the presence of aeroallergen sensitization in this population may result in earlier diagnoses and help reduce morbidity and the cost from this disease.

High-fat diet-induced obesity worsens TH2 immune response and immunopathologic characteristics in murine model of eosinophilic oesophagitis

BACKGROUND

Eosinophilic oesophagitis (EoE) is an emergent chronic immune-mediated disease of the oesophagus, which affects both children and adults. It is clinically characterized by dysphagia, food impaction and oesophageal eosinophilia. Epidemiological studies indicate that obesity can worsen allergic symptoms; however, its effect on EoE immunopathological response has not been evaluated yet. This study aimed to assess the effect of obesity on allergic inflammation and T helper-2 profile in an EoE experimental model.

METHODS

Obesity was induced by high-fat feeding. After 7 weeks of diet, male BALB/c mice were subcutaneously sensitized and orally challenged with OVA.

RESULTS

Obesity itself induced a significant mast cell and eosinophil accumulation in the oesophagus, trachea, gut and lung. After allergy induction, this number was higher, when compared to lean-allergic mice. Moreover, obese-allergic mice showed higher remodelling area, in the oesophagus, associated with higher IL-5 and TSLP mRNA expression. In contrast, FoxP3 and IL-10 were less expressed in comparison with lean-allergic mice. In addition, the amount of CD11c⁺ MHCII⁺ PDL1⁺ dendritic cells was reduced, while the number of CD11c⁺ MHCII⁺ CD80⁺ DCs and CD3⁺ CD4⁺ GATA₃ ⁺ IL-4⁺ cells was increased in obese-allergic mice in the spleen and lymph nodes when compared to lean-allergic mice.

CONCLUSION

Obesity aggravated the immune histopathological characteristics in the EoE experimental model, which was associated with the reduction in the regulatory profile, and the increased inflammatory cells influx, related to the T_H 2 profile. Altogether, the data provide new knowledge about obesity as a risk factor, worsening EoE symptoms, and contribute for future treatment strategies for this specific profile.

Epithelial origin of eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a chronic, allergen-driven inflammatory disease of the esophagus characterized predominantly by eosinophilic inflammation, leading to esophageal dysfunction. Converging data have placed the esophageal epithelium at the center of disease pathogenesis. In particular, the main EoE disease susceptibility loci at 2p23 and 5p22 encode for gene products that are produced by the esophageal epithelium: the intracellular protease calpain 14 and thymic stromal lymphopoietin, respectively. Furthermore, genetic and functional data establish a primary role for impaired epithelial barrier function in disease susceptibility and pathoetiology. Additionally, the EoE transcriptome, a set of genes dysregulated in the esophagi of patients with EoE, is enriched in genes that encode for proteins involved in esophageal epithelial cell differentiation. This transcriptome has a high proportion of esophagus-specific epithelial genes that are notable for the unexpected enrichment in genes encoding for proteases and protease inhibitors, as well as in IL-1 family genes, demonstrating a previously unappreciated role for innate immunity responses in the esophagus under homeostatic conditions. Among these pathways, basal production of the serine protease inhibitor, Kazal-type 7 (SPINK7) has been demonstrated to be part of the normal differentiation program of esophageal epithelium. Profound lost expression of SPINK7 occurs in patients with EoE and is sufficient for unleashing increased proteolytic activity (including urokinase plasminogen activator), impaired barrier function, and production of large quantities of proinflammatory and proallergic cytokines, including thymic stromal lymphopoietin. Collectively, we put forth a model in which the esophagus is normally equipped as an anti-inflammatory sensing organ and that defects in this pathway, mediated by epithelial protease/protease inhibitor imbalances, unleash inflammatory responses resulting in disorders, such as EoE.

Allergic Comorbidity in Eosinophilic Esophagitis: Mechanistic Relevance and Clinical Implications

Allergic eosinophilic esophagitis (EoE) is a chronic, allergen-mediated inflammatory disease of the esophagus, and the most common cause of prolonged dysphagia in children and young adults in the developed world. While initially undistinguished from gastroesophageal reflux disease-associated esophageal eosinophilia, EoE is now recognized as a clinically distinct entity that shares fundamental inflammatory features of other allergic conditions and is similarly increasing in incidence and prevalence. The clinical and epidemiologic associations between EoE and other allergic manifestations are well established. In addition to exaggerated rates of atopic dermatitis, IgE-mediated food allergy, asthma, and allergic rhinitis in EoE patients, each of these allergic manifestations imparts individual and cumulative risk for subsequent EoE diagnosis. As such, EoE may be a member of the "allergic march"-the natural history of allergic manifestations during childhood. Several determinants likely contribute to the relationship between these conditions, including shared genetic, environmental, and immunologic factors. Herein, we present a comprehensive review of allergic comorbidity in EoE. We discuss areas of the genome associated with both EoE and other allergic diseases, including the well-studied variants encoding thymic stromal lymphopoietin and calpain 14, among other "atopic" regions. We summarize ways that environmental factors (such as microbiome-altering pressures and aeroallergen exposure) may predispose to multiple allergic conditions including EoE. Finally, we touch on some fundamental features of type 2 inflammation, and the resulting implications for the development of multiple allergic manifestations. We conclude with an analysis of the "type 2" biologics, and how mechanistic similarities between EoE and the other allergic manifestations have important implications for screening and treatment of the allergic patient.

Pollen food allergy syndrome (PFAS): A review of current available literature

OBJECTIVE

Pollen food allergy syndrome (PFAS) is a complex syndrome posing a diagnostic and therapeutic challenge. Our objective was to summarize the available literature regarding its prevalence, pathogenesis, diagnosis, and treatment.

DATA SOURCES

A PubMed search was performed to include English language articles with the following search terms: pollen food syndrome, pollen food allergy syndrome, PFAS, oral allergy syndrome, OAS, food anaphylaxis, food components.

STUDY SELECTIONS

Human articles discussing PFAS.

RESULTS

Varying reports have been made of the prevalence of PFAS, ranging from 4.7% to greater than 20% in children and 13% to 58% in adults. Prevalence varies widely by geographic region. PFAS is typically the results of class II food allergens (e.g. sensitized to anaeroallergen, but reaction occurs due to cross reactivity from a food allergen). Commonly these reactions are limited to the oropharynx due to the lability of the proteins causing the reaction. As multiple families of proteins with varying stability cause PFAS, severe systemic reactions are also possible, as anaphylactic shock has been documented in up to 1.7% of reactions.

CONCLUSION

Pollen food allergy syndrome therefore cannot be dismissed as a benign food allergy, but it needs to be approached individually based on known risk factors.

Cardosin A endocytosis mediated by integrin leads to lysosome leakage and apoptosis of epithelial cells

Cardosin A is an aspartic protease present in large amount in the pistils of cardoon flowers. This protease is known to contain an -Arg-Gly-Asp- (RGD) motif located on the molecular surface. In this study, we found that isolated recombinant cardosin A attached to human epithelial cells A549, mediated by the binding of its RGD motif to cell surface integrins. The cell bound cardosin A was internalized to endosomes and lysosomes and triggered the permeability of lysosomal membrane leading to apoptosis of the epithelial cells. These events are identical to those observed for three RGD-containing aspartic proteases, Saps 4-6, secreted by Candida albicans. Such a process, which has been called the Trojan Horse mechanism, is believed to benefit the invasion of C. albican into the epithelium of the host. The location of the RGD motifs of cardosin A and Saps 4-6 are on the opposite ends of the homologous three-dimensional structures, suggesting that the Trojan Horse mechanism is insensitive to the RGD position. Current finding also suggests that cardosin A may have a defensive function against the ingestion of cardoon flowers by human, insects, and other herbivores.

An in-depth characterization of a large cohort of adult patients with eosinophilic esophagitis

BACKGROUND

Eosinophilic esophagitis (EoE) is a chronic, allergic, immune-mediated disease associated with increased risk of comorbid atopic conditions.

OBJECTIVE

To perform an in-depth characterization of a large cohort of manually verified adult patients with EoE, including evaluation of less studied associations, such as pollen food allergy syndrome, anaphylaxis, autoimmunity, and psychiatric comorbidities.

METHODS

We performed a manual retrospective electronic medical record review of 1,218 patients with EoE identified by International Classification of Diseases, Ninth Revision and International Classification of Disease, 10th Revision codes from the University of Pennsylvania Health Systems. Through manual medical record review, we evaluated patient demographics, family and smoking history, laboratory and endoscopic findings, treatment, and comorbid atopic, autoimmune, and psychiatric conditions.

RESULTS

A total of 950 of the 1,218 patients had biopsy-proven EoE. This cohort was predominantly male, white, and never-smokers who presented most commonly with dysphagia, with an initial biopsy results showing 49 eosinophils per high-powered field, a serum absolute eosinophilic count of 446,000/µL, and mean total IgE level of 243 IU/mL. Of the patients, 55% had impaction (of which 38% required endoscopic removal), and 56% had strictures or fibrosis (of which 56% underwent dilatation). Therapy used was predominantly (77%) medical only. Comorbid atopy, pollen food allergy syndrome, drug allergy, anaphylaxis, autoimmunity, and psychiatric illnesses were higher in the EoE cohort compared with the general University of Pennsylvania Health Systems population.

CONCLUSION

Our adult cohort of manually verified, biopsy-proven EoE had an increased risk of pollen food allergy syndrome, anaphylaxis, and comorbid autoimmune and psychiatric conditions compared with the University of Pennsylvania Health Systems population. There was also an increased prevalence of impaction and stricture or fibrosis requiring endoscopic intervention compared with the pediatric population.