Allergen-specific in vitro cytokine production in adult patients with eosinophilic esophagitis

Gene expression and clinical outcomes after dietary treatment for eosinophilic esophagitis: a prospective study

BACKGROUND

Eosinophilic esophagitis (EoE) is an allergen-mediated disease and elimination diets have proven to be effective to obtain clinical and histological remission. However, the effect of elimination diets on specific EoE transcripts and their clinical correlates is relatively unknown. The main aim of the study was to evaluate the effect of dietary treatment (four-food elimination diet [FFED]) with or without addition of amino acid-based formula (AAF) on a variety of pro-/anti-inflammatory, epithelial/barrier function and remodeling/fibrosis-related markers of disease activity and clinical correlates (eosinophils, symptoms, and endoscopic signs) in adult EoE patients.

METHODS

We conducted an analysis of biopsy samples and data collected during a randomized controlled trial with an elimination diet in adult patients with active EoE (≥15 eosinophils [eos] per high-power field [hpf]). Demographics, symptoms (SDI-score), endoscopic signs (EREFS) and peak eosinophil counts/hpf were recorded at baseline and after 6 weeks of treatment. Transcripts of 10 indicated genes were measured (qPCR) and compared to clinical correlates at baseline and after treatment.

KEY RESULTS

Forty patients (pooled FFED + FFED + AAF) (60% male, age 34.5 (interquartile range [IQR] 29-42.8 years) completed the diet. Peak eosinophil counts/hpf, symptoms and endoscopic signs were significantly decreased after 6 weeks dietary treatment. DSG-1 levels were significantly upregulated from baseline to week 6, whereas IL-13, CAPN-14, IL-5, IL-10, CCL-26, POSTN, TSLP, CPA-3, and TGF-β were significantly downregulated after 6 weeks of diet (all; <0.01). Prior to treatment, upregulation of CAPN-14 and lower levels of DSG-1 were associated with clinical fibrotic phenotypes, whereas upregulation of IL-10 was linked to food impaction phenotypes.

CONCLUSION

These findings strongly suggest that elimination diets, besides a clinical and histological response, are associated with a broad transcriptional response at the level of the esophageal epithelium.

Pathogenesis of Eosinophilic Esophagitis: A Comprehensive Review of the Genetic and Molecular Aspects

Eosinophilic esophagitis (EoE) is a relatively new condition described as an allergic-mediated disease of the esophagus. Clinically, it is characterized by dysphagia, food impaction, and reflux-like symptoms. Multiple genome-wide association studies (GWAS) have been conducted to identify genetic loci associated with EoE. The integration of numerous studies investigating the genetic polymorphisms in EoE and the Mendelian diseases associated with EoE are discussed to provide insights into the genetic risk of EoE, notably focusing on CCL26 and CAPN14. We focus on the genetic loci investigated thus far, and their classification according to whether the function near the loci is known. The pathophysiology of EoE is described by separately presenting the known function of each cell and molecule, with the major contributors being eosinophils, Th2 cells, thymic stromal lymphopoietin (TSLP), transforming growth factor (TGF)-β1, and interleukin (IL)-13. This review aims to provide detailed descriptions of the genetics and the comprehensive pathophysiology of EoE.

Pharmacological treatments for eosinophilic esophagitis: current options and emerging therapies

Introduction: The epidemiology of eosinophilic esophagitis (EoE) has increased rapidly to represent a common cause of chronic and recurrent esophageal symptoms. Current treatment options have limitations so the development of novel therapies is a matter of growing interest.Areas covered: This article provides an up-to-date discussion of current therapies and investigational options for EoE. Established anti-inflammatory treatments for EoE at present include dietary therapy, proton pump inhibitors and swallowed topic steroids, which should be combined with endoscopic dilation in case of strictures. Refractoriness, high recurrence rates, and need for long-term therapies have promoted the investigation of novel, esophageal-targeted formulas of topic corticosteroids, and monoclonal antibodies (including mepolizumab, reslizumab, QAX576, RPC4046, dupilumab, omalizumab, infliximab, and vedolizumab) for EoE, with some having been demonstrated as effective and safe in the short term. Several additional promising therapies are also discussed.Expert opinion: Several therapeutic targets have shown efficacy and will be approved to treat EoE, especially corticosteroid-sparing options and those for patients with multiple Th2-associated diseases. Personalized therapeutic strategies for initial and maintenance treatments of EoE must be rationally designed, to reduce the burden of disease and answer meaningfully the needs of all stakeholders involved in EoE.

Diagnosis and Treatment of Esophageal Candidiasis: Current Updates

Esophageal candidiasis (EC) is the most common type of infectious esophagitis. In the gastrointestinal tract, the esophagus is the second most susceptible to candida infection, only after the oropharynx. Immunocompromised patients are most at risk, including patients with HIV/AIDS, leukemia, diabetics, and those who are receiving corticosteroids, radiation, and chemotherapy. Another group includes those who used antibiotics frequently and those who have esophageal motility disorder (cardiac achalasia and scleroderma). Patients complained of pain on swallowing, difficulty swallowing, and pain behind the sternum. On physical examination, there is a plaque that often occurs together with oral thrush. Endoscopic examination is the best approach to diagnose this disease by directly observing the white mucosal plaque-like lesions and exudates adherent to the mucosa. These adherent lesions cannot be washed off with water from irrigation. This disease is confirmed histologically by taking the biopsy or brushings of yeast and pseudohyphae invading mucosal cells. The treatment is by systemic antifungal drugs given orally in a defined course. It is important to differentiate esophageal candidiasis from other forms of infectious esophagitis such as cytomegalovirus, herpes simplex virus, gastroesophageal reflux disease, medication-induced esophagitis, radiation-induced esophageal injury, and inflammatory conditions such as eosinophilic esophagitis. Except for a few complications such as necrotizing esophageal candidiasis, fistula, and sepsis, the prognosis of esophageal candidiasis has been good.

Signals from the various immune cells in promoting food allergy-induced eosinophilic esophagitis like disease

Eosinophilic esophagitis (EoE) is a recently recognized esophageal inflammatory disease with clinical manifestations arising from esophageal dysfunction. The etiology of EoE is currently being clarified and food allergy is evolving as the central cornerstone of EoE disease pathogenesis. Given the large number of eosinophils in the esophagus of people with EoE verified by data from murine models EoE is widely considered as the hallmark T-helper type 2 (Th2) disease of the esophagus. It is also known that some eosinophilic inflammation is controlled by other subsets of T cells such as Th9 or Th17 and control is also exerted by type 2 innate lymphoid cells acting together with basophils. In this paper we review results from molecular studies of mouse models in light of the results from the first clinical trials targeting key cytokines in humans and present in-depth molecular understanding of EoE.

Molecular basis and cellular mechanisms of eosinophilic esophagitis for the clinical practice

Eosinophilic esophagitis (EoE) is a chronic, allergen-driven inflammatory esophageal disease characterized by predominantly eosinophilic inflammation leading to esophageal dysfunction. Recent efforts to understand EoE have increased our knowledge of the disease. Areas covered: Multiple cells, molecules, and genes interplay with early life environmental factors in the pathophysiology of EoE to converge in the esophageal epithelium at the center of disease pathogenesis. Epithelial cells constitute a mayor cytokine source for TSLP and Calpain-14; an impaired epithelial barrier function allowing penetration of food and microbiota-derived antigens is involved in triggering and maintaining inflammation. Eosinophil and mast cell-derived products, including TGFβ, together with IL-1β and TNFα, promote epithelial mesenchymal transition in EoE, contributing to tissue remodeling by synthetizing and depositing extracellular matrix in subepithelial layers. This article aims to provide a state-of-the-art update on the pathophysiology of EoE applied to clinical practice, and latest research and developments with potential interest to improve the diagnosis and treatment of patients with EoE are revised. Expert commentary: Preliminary approaches have provided promising results toward incorporating minimally invasive methods for patient diagnosis and monitoring in clinical practice. Early diagnosis and optimized therapies will allow for personalized medicine in EoE.

Pathophysiology of Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) is a chronic inflammatory disease of the esophagus associated with an atopic predisposition which appears to be increasing in prevalence over the last few decades. Symptoms stem from fibrosis, swelling, and smooth muscle dysfunction. In the past two decades, the etiology of EoE has been and is continuing to be revealed. This review provides an overview of the effects of genetics, environment, and immune function including discussions that touch on microbiome, the role of diet, food allergy, and aeroallergy. The review further concentrates on the pathophysiology of the disease with particular focus on the important concepts of the molecular etiology of EoE including barrier dysfunction and allergic hypersensitivity.

Utility of 15(S)-HETE as a Serological Marker for Eosinophilic Esophagitis

The pathogenesis of eosinophilic esophagitis (EoE) involves Th2-mediated eosinophil recruitment and degranulation into the esophagus. However, measuring serum Th2 cytokines, eosinophils, and eosinophil-derived products does not reliably distinguish EoE from control populations. Non-invasive methods to diagnose EoE are lacking. We evaluated the diagnostic value of a novel candidate biomarker of EoE: 15(S)-hydroxyeicosatetraenoic acid (HETE). We used immunoassay to measure 15(S)-HETE and cytokine profiles in patients undergoing endoscopy with known or suspected EoE. 31 subjects were enrolled, 16 with EoE, and 15 with an alternate diagnosis. 15(S)-HETE was elevated in the EoE group compared to non-EoE group. The sensitivity and specificity of 15(S)-HETE to be used as a non-invasive marker is 50% and 80%, respectively. 15(S)-HETE may aid in the diagnosis of EoE.

Biological therapies for eosinophilic gastrointestinal diseases

The scientific basis and the clinical application of mAb therapies that target specific immunologic pathways for eosinophilic gastrointestinal diseases are areas of active interest. There is a growing recognition of a subset of patients with eosinophilic esophagitis whose disease does not respond well to topical steroids or elimination diets. In addition, long-term use of corticosteroids presents possible risks that are currently being evaluated. Systemic therapy with a biologic agent offers potential advantages as a global approach that could limit the need for multiple, locally active medical therapies and allergen avoidance. The identification of novel biologic strategies is ongoing, and the recent validation of instruments and outcome measures to assess disease activity has proved essential in demonstrating efficacy. Studies using biologics that target IL-13 pathways in the treatment of eosinophilic esophagitis have demonstrated substantial promise.

Diagnosis and Management of Eosinophilic Esophagitis

Unlike traditional food allergies, immunoglobulin E (IgE) is not a key mediator of eosinophilic esophagitis (EoE). Nonetheless, foods antigens are important triggers of EoE, and allergists play an important role in management of this chronic disease. This review addresses insights into the diagnosis and management as it relates to our evolving understanding about the pathogenesis of EoE.

Tissue Remodeling in Chronic Eosinophilic Esophageal Inflammation: Parallels in Asthma and Therapeutic Perspectives

Chronic eosinophilic inflammation is associated with tissue remodeling and fibrosis in a number of chronic T-helper 2 (Th2)-mediated diseases including eosinophilic esophagitis (EoE) and asthma. Chronic inflammation results in dysregulated tissue healing, leading to fibrosis and end organ dysfunction, manifesting clinically as irreversible airway obstruction in asthma and as esophageal rigidity, strictures, narrowing, dysmotility, dysphagia, and food impactions in EoE. Current therapies for EoE and asthma center on reducing inflammation-driven tissue remodeling and fibrosis with corticosteroids, coupled with symptomatic control and allergen avoidance. Additional control of Th2 inflammation can be achieved in select asthma patients with biologic therapies such as anti-IL-5 and anti-IL-13 antibodies, which have also been trialed in EoE. Recent molecular analysis suggests an emerging role for structural cell dysfunction, either inherited or acquired, in the pathogenesis and progression of EoE and asthma tissue remodeling. In addition, new data suggest that inflammation-independent end organ rigidity can alter structural cell function. Herein, we review emerging data and concepts for the pathogenesis of tissue remodeling and fibrosis primarily in EoE and relevant pathogenetic parallels in asthma, focusing additionally on emerging disease-specific therapies and the ability of these therapies to reduce tissue remodeling in subsets of patients.

An Overlook to the Characteristics and Roles Played by Eotaxin Network in the Pathophysiology of Food Allergies: Allergic Asthma and Atopic Dermatitis

Investigations revealed substantial parts accomplished by chemokines specifically eotaxins and their specific receptors. They are functionally involved in the modulation of the pathologic state of tissue inflammation which is as a result of allergic reactions. Chemokines as small proteins with approximately 8-10 kDa molecular weight are considered and fit in the bigger family of cytokines, containing basic heparin-binding polypeptide mediators. Chemokines actively interfere in the processes of selective, oriented leukocyte (including eosinophil) recruitment. As eminent from their name, more specifically, eotaxins are specialized for eosinophils' oriented locomotion toward allergic inflamed regions. To date, three members are defined for eotaxin subfamily as follows: eotaxin-1 (CCL11), eotaxin-2 (CCL24), and eotaxin-3 (CCL26), all of them bind to and activate CCR3 but have a low level of homology and appear to exhibit different physiological potentials. Allergy is described as a clinical state in which a pathologic hypersensitivity reaction is always initiated throughout an immunologic mechanism; similar to other immunologic reactions, an allergic reaction could also either be antibody or cell mediated. This type of allergic reactions occurs in all age groups and damages several different organs, having a significant impact on the emotional and social health of patients and their families and relatives. Concerning introductory comments introduced above, the authors of the present review attempted to collect and provide the latest evidences and information regarding the correlation between expression of eotaxin family members and allergy, in a wider extent, in two important allergic disorders: atopic asthma (AA) and atopic dermatitis (AD). Overall, concerning the most recent articles published within the database in the life sciences literature regarding the fundamental role(s) played by eotaxins in the pathogenesis of AA and AD, the authors of the current article propose that eotaxins (CCL11, CCL24, and CCL26) play key role(s) during symptomatic inflammatory responses raised in response to allergic crisis of these two clinical states.

Eosinophilic Esophagitis: A Comprehensive Review

Eosinophilic esophagitis (EoE) is an emerging chronic atopic clinical-pathologic disease with an estimated prevalence of 1/1000 similar to the one of Crohn's diseases. Usually, EoE is firstly suspected due to symptoms that are caused by esophageal dysfunction and/or fibrosis. EoE diagnosis is confirmed if the esophageal biopsy shows at least 15 eosinophils per high power field (eos/hpf) as a peak value in one or more of at least four specimens obtained randomly from the esophagus. Most of the patients affected by EoE have other atopic diseases such as allergic rhinitis, asthma, IgE-mediated food allergies, and/or atopic dermatitis. The local inflammation is a T helper type 2 (Th2) flogosis, which most likely is driven by a mixed IgE and non-IgE-mediated reaction to food and/or environmental allergens. Recently published genetic studies showed also that EoE is associated with single nucleotide polymorphism (SNP) on genes which are important in atopic inflammation such as thymic stromal lymphopoietin (TSLP) located close to the Th2 cytokine cluster (IL-4, IL-5, IL-13) on chromosome 5q22. When the EoE diagnosis is made, it is imperative to control the local eosinophilic inflammation not only to give symptomatic relief to the patient but also to prevent complications such as esophageal stricture and food impaction. EoE is treated like many other atopic diseases with a combination of topical steroids and/or food antigen avoidance.

Eosinophilic disorders of the gastro-intestinal tract: an update

Eosinophilic diseases of the gastrointestinal tract, including eosinophilic esophagitis (EoE) and eosinophilic gastroenteritis (EGE), are rare chronic pathologies of the digestive system, with an immuno-mediated pathogenesis. Recent data suggest that, together with the “classic” IgE-response to allergens, also a delayed hypersensitivity mechanism could be involved in the development of eosinophilic disorders. EoE and EGE were studied only in the latest decades and as a consequence accurate data are not yet available, concerning not only pathogenesis, but also epidemiology, treatment and outcomes. The diagnosis of EoE is centered on endoscopic findings but the certainty is obtained by histological examination from biopsy samples, that has a sensitivity of 100% when based on five samples. The currently available treatments include topical corticosteroids, specific diets and endoscopic treatment. Concerning EGE, three subtypes (mucosal, muscular, and serosal) were identified. The diagnosis is based, as for EoE, on endoscopic and histological assessment, and the treatment includes pharmacological and dietetic approaches. Further studies are warranted in order to better define the etiology and pathogenesis of eosinophilic diseases of the gastrointestinal tract, and thus to develop more appropriate and specific therapies.

The Inflammatory Milieu of Eosinophilic Esophagitis: A Contemporary Review With Emphasis in Putative Immunohistochemistry and Serologic Markers

Eosinophilic esophagitis is a chronic disease characterized by esophageal dysfunction, frequent clinical history of atopy, and eosinophilic inflammation of the esophagus. Within the esophageal mucosa, there is a wide variety of immune mediators, chemotactic factors, mediators of transcription, and markers of epithelial differentiation and integrity that are overexpressed or underexpressed in eosinophilic esophagitis, offering many candidates for biomarkers with diagnostic or prognostic potential. In this review, we summarize the results from studies performed so far to evaluate the detection of these markers by immunohistochemistry on esophageal biopsies. In addition, we briefly describe some attempts to identify markers that could be detected in serum to be used to diagnose or monitor the disease without the need of a biopsy.

Eosinophilic esophagitis is characterized by a non-IgE-mediated food hypersensitivity

Eosinophilic esophagitis (EoE) is a chronic disease characterized clinically by symptoms of esophageal dysfunction and histologically by eosinophil-predominant inflammation. EoE is frequently associated with concomitant atopic diseases and immunoglobulin E (IgE) sensitization to food allergens in children as well as to aeroallergens and cross-reactive plant allergen components in adults. Patients with EoE respond well to elemental and empirical food elimination diets. Recent research has, however, indicated that the pathogenesis of EoE is distinct from IgE-mediated food allergy. In this review, we discuss the individual roles of epithelial barrier defects, dysregulated innate and adaptive immune responses, and of microbiota in the pathogenesis of EoE. Although food has been recognized as a trigger factor of EoE, the mechanism by which it initiates or facilitates eosinophilic inflammation appears to be largely independent of IgE and needs to be further investigated. Understanding the pathogenic role of food in EoE is a prerequisite for the development of specific diagnostic tools and targeted therapeutic procedures.

Mechanisms of Disease of Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) is a recently recognized inflammatory disease of the esophagus with clinical symptoms derived from esophageal dysfunction. The etiology of EoE is now being elucidated, and food hypersensitivity is emerging as the central cornerstone of disease pathogenesis. Herein, we present a thorough picture of the current clinical, pathologic, and molecular understanding of the disease with a focus on disease mechanisms.

Do We Know What Causes Eosinophilic Esophagitis? A Mechanistic Update

The mechanisms underlying eosinophilic esophagitis (EoE) have been intensely investigated, and significant advances have been made in understanding the pathogenesis of EoE. EoE is defined as a chronic immune/antigen-mediated disease, characterized clinically by symptoms of esophageal dysfunction and histologically by an esophageal eosinophilic infiltrate. In this paper, we will review the current knowledge of EoE pathophysiology based on both animal and human data and discuss possible etiologic mechanisms from the genetic and environmental perspectives. EoE is a Th2-predominant inflammatory process triggered by allergens. Proinflammatory cytokines and chemokines recruit eosinophils and other effector cells, such as mast cells, into the esophageal epithelium, where they cause direct damage and promote esophageal remodeling. The genetic expression profile of EoE has been described, and several single nucleotide polymorphisms have been identified and associated with EoE. While this genetic contribution is important, it is difficult to postulate that EoE is primarily a genetic disease. Given the rapid epidemiologic changes in the incidence and prevalence of EoE over the past two decades, environmental factors may be the driving force. While it is not known what causes EoE in an individual patient at a specific time, the current hypothesis is that there is a complex interaction between genetic factors and environmental exposures that remains to be elucidated.

Small intestinal permeability in patients with eosinophilic oesophagitis during active phase and remission

BACKGROUND

Eosinophilic oesophagitis (EoE) is presumed to be an isolated oesophageal disease; yet other allergic diseases associated with eosinophilic infiltration of target tissues, such as asthma and eczema, show perturbed functions of other sites that may be involved in the diathesis of allergy modulation.

AIM

To analyse small intestinal permeability in patients with active EoE and in a separate group of patients in remission.

METHODS

Small bowel permeability was determined using a dual sugar method by calculating lactulose:mannitol (L:M) ratio in 17 patients who met consensus criteria for active EoE (>15 eos/HPF) and 8 patients in remission (<5 eos/HPF). Data from 28 healthy controls was used for comparison.

RESULTS

Patients with active EoE had significantly higher L:M ratios when compared to controls (0.045 vs. 0.033, p<0.001) and to EoE in remission (0.041 vs. 0.027, p<.001). There was no significant difference in L:M between the group with EoEin remission and healthy controls. The current data show that L:M ratio of 0.033 also provides a reasonable cut-off that defined the active EoE group compared to patients in remission. The main component explaining the change in L:M ratio was increased absorption (and excretion) of lactulose ((1601 ± 106 ug) when compared to the EoE remission (969 ± 91 ug) and control (1043 ± 92 ug, p<.001) groups.

CONCLUSIONS

Small bowel permeability is overall increased in patients with active EoE, and is normal in patients with EoE in remission when compared to healthy controls. The role of the small bowel in active EoE deserves further investigation.

Immunotherapeutic approaches for the treatment of eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a clinical pathologic disease characterized by symptoms of esophageal dysfunction and eosinophilia of the esophagus. When the diagnosis is confirmed, it is important to treat the eosinophilic inflammation not only to control the presenting symptoms, but also to prevent acute and chronic complications. The pathogenesis of EoE is most likely a mixed IgE and non-IgE food-mediated reaction, where Th2 cytokines drive esophageal eosinophilia as in other atopic diseases. Hence, it is not surprising that therapy is based on inflammation control, with steroids (oral or topical) and/or food antigen avoidance. However, these treatment options are not specific, reduce the quality of life of patients and have significant side effects, therefore, there is an ongoing effort to design more specific immunotherapies. In this review, we review standard and immunotherapeutic options for EoE treatment, such as anti-IL-5, anti-TNFα, anti-IgE, anti-CRTH, oral allergy desensitization and environmental immunotherapy.

A rare cause of chronic dysphagia: eosinophilic esophagitis†

Eosinophilic esophagitis (EE) is attributable to environmental factors, allergens and several immunological causes. The most typical symptoms include dysphagia and sensation of food impingement in the retrosternal area. Although its clinical features resemble those of gastroesophageal reflux, proton pump inhibitors are not effective for its treatment. The diagnosis of EE is dependent on the pathological detection of eosinophilic infiltration in esophageal mucosa. In this study, we evaluated a patient who applied to our clinic with complaints of long-term difficulty in swallowing, sensation of food sticking while eating and weight loss; the patient was diagnosed with EE, following biochemical, radiological, endoscopic and pathological assessments and was treated with steroids. The results show that EE should be considered in the differential diagnosis of patients with dysphagia and food impingement in the retrosternal area, and the diagnosis should be confirmed through multiple esophageal biopsies.

Eosinophilic esophagitis: a clinicopathological review

Eosinophilic esophagitis (EoE) is considered to be a chronic antigen-driven disease whereby food and/or aeroallergens induce a chronic inflammatory infiltrate in the esophagus, resulting in pathological hyperplasia of the epithelia and muscular layers, and fibrosis of the lamina propria (referred to collectively as remodelling) and the symptoms of dysphagia and food impaction. EoE shares features with other atopic conditions of asthma and atopic dermatitis, such as a TH2 cytokine milieu and a mixed inflammatory infiltrate of eosinophils, mast cells and lymphocytes. Relatively distinct features include the strong male predominance amongst adult patients, and the expression of the eosinophil chemokine eotaxin 3. Current first line treatments such as strict dietary modification and corticosteroids fail many patients. Looking forward, clarification of distinct genotype/phenotype associations, determining the reversibility of remodelling following treatment, and the development of new pharmacotherapies that target fibrotic pathways (as opposed to eosinophilic inflammation per se) or specifically improve barrier integrity appear relevant.

Cellular and molecular immunological mechanisms in eosinophilic esophagitis: an updated overview of their clinical implications

Eosinophilic esophagitis (EoE) is a pathophysiologically complex disorder driven by distinct, multiple mechanisms involving a large number of cells, molecules, and genes. Associated with food allergy from its initial descriptions, a key role for the Th2-type cytokines IL-5 and IL-13 in recruiting and activating eosinophils has been described. Epithelial cells have been recognized as major effectors in initiating EoE, both through their recruitment of iNKT cells towards the esophageal epithelium, which constitutes a major cytokine source, and through the release of eotaxin-3 and other chemoattractants. Epithelial and mesenchymal-released TSLP is a key regulator for which a connecting role between the adaptive and innate mucosal-associated immune response has been suggested. Finally, activated eosinophil- and mast cell-derived TGF β1 secretion is crucial in EoE-associated tissue remodeling.

Mucosal cytokine profiles in paediatric eosinophilic oesophagitis: a case-control study

BACKGROUND

Eosinophilic oesophagitis is an inflammatory condition characterized by a dense eosinophilic infiltrate. The migration of eosinophils into the oesophagus is influenced by cytokines such as IL-5, IL-13 and eotaxin-3. The aim of this study was to evaluate changes in the cytokine expression profiles (IL-5, IL-13 and eotaxin-3/CCL26) in children after topical steroid treatment.

METHODS

a prospective case-control study was performed in 23 paediatric patients (age 5-16 years) with a histological diagnosis of eosinophilic oesophagitis. Histological evaluation and cytokine levels assay (IL-5, IL-13 and eotaxin-3/CCL26) in the proximal and distal oesophagus were performed before, and after 8 weeks of topical budesonide. Data were compared with a matched healthy control group.

RESULTS

quantitative expression levels of IL-5, IL-13 and eotaxin-3 were significantly higher in the eosinophilic oesophagitis group both compared to healthy subjects (p<0.0001). A significant reduction of the eosinophil infiltrate as well as of IL-5, IL-13 and eotaxin-3 mucosal profiles was observed after steroid treatment both at the proximal and distal oesophagus (p<0.0001).

CONCLUSIONS

IL-5, IL-13 and eotaxin-3/CCL26 are significantly over-expressed in the oesophageal epithelium of children with eosinophilic oesophagitis. Topical steroid treatment (inhaled and swallowed budesonide) can induce clinical response with partial mucosal remission.

Allergic mechanisms in eosinophilic esophagitis

Eosinophilic esophagitis is rapidly increasing in incidence. It is associated with food antigen-triggered, eosinophil-predominant inflammation, and the pathogenic mechanisms have many similarities to other chronic atopic diseases. Studies in animal models and from patients have suggested that allergic sensitization leads to food-specific IgE and T-helper lymphocyte type 2 cells, both of which seem to contribute to the pathogenesis along with basophils, mast cells, and antigen-presenting cells. In this review our current understandings of the allergic mechanisms that drive eosinophilic esophagitis are outlined, drawing from clinical and translational studies in humans as well as experimental animal models.

Atopy and the gastrointestinal tract--a review of a common association in unexplained gastrointestinal disease

In addition to diseases conventionally associated with atopy there is increasing recognition that atopy is also linked to a spectrum of gastrointestinal (GI) manifestations, including food allergy, primary eosinophilic GI disease, functional gastrointestinal disorders, gluten interactions, gastroesophageal reflux disease and inflammatory bowel disease. These associations may be underpinned by shared genetic susceptibilities, initiation of related immune pathways and common patterns of exposure to environmental cues, including allergen/pathogen encounters and variations in the composition of the intestinal microbiota. Further scrutiny of GI diseases with prominent allergic-type immune responses may yet redefine treatment paradigms for these common and important atopy-associated diseases. Looking forward, interventions by manipulation of the microbiota or host immune responses hold promise, but there is still room for further exploration of this novel field of host susceptibility, host-microbe interactions and atopy-associated GI diseases.

Emerging therapeutic strategies for eosinophilic esophagitis

OPINION STATEMENT

Eosinophilic esophagitis (EoE) is recognized as an increasingly common cause of chronic and recurrent esophageal symptoms that significantly impact quality of life and may occasionally result in severe complications in both pediatric and adult patients. The disease is triggered and maintained by exposure to food antigens in most patients, with an additional role proposed for airborne allergens. Different diet-based approaches focused on restricting potentially offending foods have proven to be effective long-term therapies for EoE. Dietary therapy is thus an attractive, yet challenging treatment option that should be considered for all pediatric and adult EoE patients. However, limitations related to food restriction, patient willingness to undergo repeated endoscopies and biopsies, and the variable results of allergy testing imply that dietary management is for the most part currently restricted to highly motivated healthcare providers treating highly motivated patients reluctant to utilize drug-based therapy on a chronic basis. Pharmacological therapies for EoE mainly comprise swallowed topical steroids, especially fluticasone propionate and budesonide, which were originally developed to treat bronchial asthma and are now extensively used "off label" in EoE patients. In fact, topical steroids currently constitute the prevailing therapeutic option and will probably continue to do so in the near future; indeed, several randomized clinical trials are currently underway to test these drugs for approval as the first pharmacological agents for EoE patients. Immunomodulators and several anti-allergic agents must be further assessed as therapeutic alternatives for refractory cases or patients with complications. Endoscopic dilation represents the third pillar in the therapeutic management of EoE patients, since they frequently present reductions in the esophageal caliber as a result of collagen deposition and a progressive fibrous remodeling process promoted by chronic eosinophilic infiltration. Dilation provides at least temporary symptom relief with similar complication rates to esophageal strictures from a different origin. However, although repeated endoscopic dilation has sometimes been used as the sole therapy for EoE, it best constitutes an adjuvant therapy along with dietary or pharmacological-based interventions, especially since dilation has no effect on the underlying esophageal inflammation. Current therapeutic management of EoE varies widely, with physician experience being a major explanatory factor. New evidence from ongoing research on EoE should thus seek to define a common treatment algorithm to optimize EoE patient management.

Limited role of allergy testing in patients with eosinophilic gastrointestinal disorders

BACKGROUND AND AIM

Allergies have been implicated in the pathogenesis of eosinophilic gastrointestinal disorders, although it remains unknown what type of allergen is closely associated with their development. The aim of this study is to investigate the possible involvement of food and/or aeroallergen factors in eosinophilic gastrointestinal disorders.

METHODS

Eighteen patients with eosinophilic esophagitis (EoE), 23 with eosinophilic gastroenteritis (EGE), and 28 healthy volunteers were enrolled. The levels of total serum immunoglobulin E (IgE) and 33 different allergen-specific IgE antibodies, including those for six foods used in a standard EoE elimination diet, were determined in each subject. Serum antigen-specific IgE levels were measured using a chemiluminescence enzyme immunoassay with a multiple antigen simultaneous test 33 (MAST33). The expression patterns of specific antigens were compared among the groups.

RESULTS

The mean level of total IgE antibodies was significantly higher in patients with EGE (553.6 ± 115.3 IU/mL) than the healthy volunteers (230.6 ± 87.1 IU/mL). Two thirds of all subjects had sensitivity to at least one inhaled antigen. In positive cases, allergies against multiple antigens were more frequently seen in the EoE and EGE patients. Japanese cedar and dust mite aeroallergens were more prevalent than food antigens.

CONCLUSIONS

Consistent with higher levels of serum total IgE antibodies, patients with EoE and EGE were frequently sensitized to several different allergens. Reactions to aeroallergens were more prevalent in these groups, although no particular antigen causing EoE and/or EGE was detected by measuring serum antigen-specific IgE antibodies.

Eosinophilic esophagitis: which role for food and inhalant allergens?

Eosinophilic esophagitis is a chronic inflammatory disease of the esophagus, immune/antigens mediated, whose incidence is increasing both in adults and pediatric population. It is clinically characterised by symptoms related to esophageal dysfunction and associated with eosinophil-predominant esophageal inflammation. The role of atopy has been clearly demonstrated both in epidemiological and experimental studies and has important implications for diagnosis and therapy. In fact, many evidences show that food and inhalant allergens represent the most important factors involved in the progress of the disease. Several studies have reported that, in a range between 50 and 80%, patients with eosinophilic esophagitis have a prior history of atopy, and for them, the presence of allergic rhinitis, asthma or atopic dermatitis is frequent. Skin tests are able to identify in most patients the allergens involved, allowing a correct dietary approach in order to achieve the remission of symptoms and the biopsy normalization.

Eosinophilic esophagitis: updated consensus recommendations for children and adults

Eosinophilic esophagitis (EoE) is a clinicopathologic condition of increasing recognition and prevalence. In 2007, a consensus recommendation provided clinical and histopathologic guidance for the diagnosis and treatment of EoE; however, only a minority of physicians use the 2007 guidelines, which require fulfillment of both histologic and clinical features. Since 2007, the number of EoE publications has doubled, providing new disease insight. Accordingly, a panel of 33 physicians with expertise in pediatric and adult allergy/immunology, gastroenterology, and pathology conducted a systematic review of the EoE literature (since September 2006) using electronic databases. Based on the literature review and expertise of the panel, information and recommendations were provided in each of the following areas of EoE: diagnostics, genetics, allergy testing, therapeutics, and disease complications. Because accumulating animal and human data have provided evidence that EoE appears to be an antigen-driven immunologic process that involves multiple pathogenic pathways, a new conceptual definition is proposed highlighting that EoE represents a chronic, immune/antigen-mediated disease characterized clinically by symptoms related to esophageal dysfunction and histologically by eosinophil-predominant inflammation. The diagnostic guidelines continue to define EoE as an isolated chronic disorder of the esophagus diagnosed by the need of both clinical and pathologic features. Patients commonly have high rates of concurrent allergic diatheses, especially food sensitization, compared with the general population. Proved therapeutic options include chronic dietary elimination, topical corticosteroids, and esophageal dilation. Important additions since 2007 include genetic underpinnings that implicate EoE susceptibility caused by polymorphisms in the thymic stromal lymphopoietin protein gene and the description of a new potential disease phenotype, proton pump inhibitor-responsive esophageal eosinophila. Further advances and controversies regarding diagnostic methods, surrogate disease markers, allergy testing, and treatment approaches are discussed.

Understanding eosinophilic esophagitis: the cellular and molecular mechanisms of an emerging disease

Eosinophilic esophagitis (EoE) has been increasingly recognized as a unique clinicopathological entity over the past two decades. In this short time, the mechanisms of a complex disease have begun to emerge. Patient studies suggest that EoE is an immunologic disease related to atopy. At the cellular level, eosinophils, mast cells, and B and T lymphocytes are increased in the esophageal mucosa in a patchy distribution throughout the length of the esophagus. Laboratory investigations have implicated aeroallergens, food allergens, and a unique T helper type 2 cytokine profile. EoE appears to be an antigen-driven hypersensitivity reaction characterized by a mixed IgE-dependent/delayed-type reaction and a distinct cascade of cytokines and growth factors. The causative events that lead to EoE in humans remain unknown.

A striking local esophageal cytokine expression profile in eosinophilic esophagitis

BACKGROUND

Eosinophilic esophagitis (EE) is an emerging worldwide disease that mimics gastroesophageal reflux disease.

OBJECTIVE

Early studies have suggested that esophageal eosinophilia occurs in association with T(H)2 allergic responses, yet the local and systemic expression of relevant cytokines has not been well characterized.

METHODS

A human inflammatory cytokine and receptor PCR array containing 84 genes followed by PCR validation and multiplex arrays were used to quantify cytokine mRNA in esophageal biopsies and blood samples.

RESULTS

Esophageal transcripts of numerous chemokines (eg, chemokine [C-C motif] ligand [CCL] 1, CCL1, CCL23, CCL26 [eotaxin-3], chemokine [C-X-C motif] ligand [CXCL] 1, and CXCL2), cytokines (eg, IL13 and ATP-binding cassette, subfamily F, member 1), and cytokine receptors (eg, IL5 receptor, alpha) were induced at least 4-fold in individuals with EE. Analysis of esophageal biopsies (n = 288) revealed that eotaxin-3 mRNA level alone had 89% sensitivity for distinguishing individuals with and without EE. The presence of allergy was associated with significantly increased esophageal expression of IL4 and IL5 mRNA in patients with active EE. We identified 8 cytokines (IL-4, IL-13, IL-5, IL-6, IL-12p70, CD40 ligand, IL-1α, and IL-17) whose blood levels retrospectively distinguished 12 patients without EE from 13 patients with EE with 100% specificity and 100% sensitivity. When applied to a blind, prospectively recruited group of 36 patients, the cytokine panel scoring system had a 79% positive predictive value, 68% negative predictive value, 61% sensitivity, and 83% specificity for identifying EE.

CONCLUSION

Evidence is presented that IL13 and IL5 associate with eosinophil and eotaxin-3 levels, indicating the key role of adaptive T(H)2 immunity in regulating eotaxin-3-driven esophageal eosinophilia in the absence of a consistent systemic change in cytokines.

Treatment of eosinophilic esophagitis: how should we manage the disease?

Eosinophilic esophagitis (EE) is a chronic clinicopathologic syndrome and is the latest inflammatory disease of the esophagus described in literature. It seems to have a multifactorial etiology. Its causes include exposure to food or airborne allergens that affect individuals who may be genetically predisposed and exposure to the acid could also modulate the inflammatory response at esophageal level. However, we currently do not know how each of these possible etiologic factors contribute to the development of the disease that is essential to define specific treatment. We have used 3 different therapeutic approaches that were effective in patients with EE: various antiinflammatory drugs that are useful in treating asthma, controlling the exposure to allergens, particularly with respect to dietary changes and dilation of the esophagus. Although none of these treatments have absolute advantages, they can efficiently control the symptoms and inflammation in a large number of patients. Each treatment option should be assessed on a case-by-case basis in accordance with the experience of each center, the patients' characteristics, their sensitivity to allergens and their preferences. This article provides the latest information on the different treatment options for patients with EE, analyzing the advantages and disadvantages of each pathology and it offers practical recommendations on how to manage these patients who are being more frequently diagnosed.

Food allergy and eosinophilic esophagitis

PURPOSE OF REVIEW

Eosinophilic esophagitis (EoE) is a chronic allergic disease of the esophagus. A mix of immediate, IgE-mediated and delayed, non-IgE-mediated immunological reactions to foods is thought to play a role in EoE. Our purpose is to review available clinical and research evidence for this link between food allergy and EoE.

RECENT FINDINGS

Various food elimination trials resulted in various rates of disease remission. Exclusive amino acid formula-based dietary trials resulted in more than 90% remission in children with EoE. Empiric elimination diets consisting of avoidance of foods commonly known to cause hypersensitivity reactions resulted in 50-74% disease remission. When diets were tailored based on results from skin prick and atopy patch tests, remission rates were comparable. Translational research studies performed on esophageal tissues and peripheral blood of patients with EoE demonstrated an allergic T-helper type 2 phenotype, though mechanisms linking the disease to food allergens are not fully addressed.

SUMMARY

Foods appear to be important allergic triggers in EoE. Identification of these triggers, however, remains a challenge. Research is needed to elucidate at which point in the pathogenesis of EoE foods become important so that their role can be better understood, and develop better tests to identify these foods.

Esophageal Eosinophilia

The presence of esophageal eosinophilia encompasses a broad differential diagnosis, and at times a specific histologic diagnosis is not possible. This content provides a systematic approach to esophageal squamous eosinophilia with emphasis on specific, distinguishing features within this expansive differential.

An update on the immunopathogenesis of eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a chronic clinicopathological entity characterized by large numbers of intraepithelial eosinophils infiltrating the esophageal mucosa, which is not caused by gastroesophageal reflux. This disease has become widely recognized over the past few years and new methods have been developed to reveal its underlying pathophysiological mechanisms. Owing to the high prevalence of food and/or airborne allergen sensitization in EoE patients, the allergic nature of the disease had to be defined, which has certain factors in common with other IgE-dependent entities, such as bronchial asthma or allergic rhinitis. Of these, some cytokines and chemokines previously studied in asthma have also been implicated in molecular mechanisms causing eosinophil-rich esophageal inflammation. However, the role played by IgE in relation to the esophageal eosinophilic infiltrate must be clarified, together with the possible function of mast cells in the inflammatory infiltrate and its activation stimuli. A putative role has also been recently suggested for gastroesophageal reflux in the origin of EoE that should be profoundly analyzed, together with the role of specific genes implicated in other digestive inflammatory disorders. This article reviews recent advances in the immunopathogenesis of EoE, which should also consider other pathways to activate the esophageal mucosal immune system.

Eosinophilic gastrointestinal disease and peanut allergy are alternatively associated with IL-5+ and IL-5(-) T(H)2 responses

BACKGROUND

Both anaphylactic food allergy and eosinophil-associated gastrointestinal disorders are associated with T(H)2 responses and food-specific IgE, yet they have very different clinical presentations.

OBJECTIVE

To determine whether the clinical differences between anaphylactic food allergy and eosinophil-associated gastrointestinal disorders are reflected in different T(H)2 responses to foods.

METHODS

Subjects with peanut allergy (PA), subjects with allergic eosinophilic gastroenteritis (AEG), and nonatopic subjects were enrolled. Antigen-specific IL-4, IL-5, IFN-gamma, and TNF T-cell responses to peanut, soy, and shrimp were measured by using intracellular cytokine staining and polychromatic flow cytometry.

RESULTS

Two distinct subpopulations of T(H)2 cells were found: IL-5+ T(H)2 (IL-4+, IL-5+) and IL-5(-) T(H)2 (IL-4+, IL-5(-)) cells. Peanut-specific IL-5+ T(H)2 cells were present at a 20-fold greater frequency in AEG versus PA (81 vs 4 per 10(6) CD4 cells; P = .05), whereas there were similar frequencies of IL-5(-) T(H)2 cells (67 vs 41 per 10(6)). For all foods, IL-5+ T(H)2 cells accounted for a significantly greater fraction of the antigen-specific cells in AEG relative to PA (29% vs 4%; P < .0001). In PA but not AEG, IL-5(-) T(H)2 responses to peanut were highly correlated with peanut-specific IgE (r = 0.87 vs 0.55, respectively). All subject groups elicited similar very low-magnitude T(H)1 responses to food antigens.

CONCLUSION

T(H)2 responses are composed of 2 subpopulations: IL-5+ T(H)2 and IL-5(-) T(H)2 cells. IL-5+ T(H)2 food allergen-specific T cells are singularly associated with AEG, whereas PA is associated with a dominant IL-5(-) T(H)2 response. These results suggest heterogeneity within the T(H)2 cytokine response, with different T(H)2 responses alternatively favoring IgE-mediated or eosinophil-dominant immunopathology.

Mechanism of eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a newly recognized disease and is an emerging entity throughout developing and developed countries, including the United States. Therefore, understanding the causes, natural history, diagnosis, and management is important for future therapeutic interventions. The pathogenesis of EoE is still not clear, but a growing body of evidence has established that this condition represents a T-cell-mediated immune response involving several proinflammatory mediators and chemoattractants known to regulate eosinophilic accumulation in the esophagus, such as IL-4, IL-5, IL-3 and eotaxin-1, -2, and -3. Determining the mechanism or mechanisms through which human esophageal-derived factors ultimately induce the functional abnormalities observed, and to which antigens patients who have EoE are sensitized that lead to the manifestation of symptoms, is of significant interest.

The role of lymphocytes in eosinophilic gastrointestinal disorders

Eosinophilic gastrointestinal diseases (EGIDs) encompass a variety of disorders including eosinophilic esophagitis (EE), eosinophilic gastroenteritis (EG), and eosinophilic colitis. Although the pathogenesis of EGIDs is still poorly understood, dietary food antigens have been shown to cause EGIDs through several short-term clinical studies. The relationship of EGIDs with food allergy points to a potential breach of oral tolerance in EGIDs and to a potentially important role played by lymphocytes in responding to the oral food antigens. This article discusses the concept of oral tolerance, the available evidence for the role that lymphocytes play in the induction and pathogenesis of EGIDs, and the evidence for a potential breach in oral tolerance in EGIDs.

Biology and treatment of eosinophilic esophagitis

Eosinophilic esophagitis is a recently recognized but expanding disorder characterized by antigen-driven eosinophil accumulation in the esophagus. Symptoms frequently mimic those of gastroesophageal reflux disease, but the diseases are distinct in their histopathology, gene expression signature, response to therapy, hereditary risk, and association with allergies. The pathogenesis of eosinophilic esophagitis involves environmental and genetic factors, particularly food antigens and expression level of the eosinophil chemoattractant eotaxin-3, respectively. Analyses of gene expression signatures and animal models have indicated the importance of adaptive T-cell immunity that involves interleukin-5 and interleukin-13-induced esophageal epithelial cell responses. Symptoms, dysregulation of esophageal gene expression, and pathology are largely reversible following reduced exposure to specific food antigens as well as anti-inflammatory therapy, but chronic treatment is necessary to prevent relapse. Therefore, eosinophilic esophagitis is a disease with unique features that include chronic esophagitis, atopy, immune sensitization to oral antigens, reversibility, and familial association.

The role of mast cells in eosinophilic esophagitis

Eosinophilic esophagitis (EE) is a chronic inflammatory disease of the esophagus which is characterized by the presence of dense infiltrate of eosinophilic leukocytes restricted to this organ mucosa. Accumulating published evidence suggests a strong role of mast cells in the inflammatory infiltrate in the physiopathology of EE. We have reviewed published articles with relevant information about the presence and possible role of mast cells in EE. Although mast cells have been studied indirectly in EE, reported data allow us to confirm that the number of mast cells infiltrating the esophageal epithelium in adult and child patients with EE is higher with respect to the normal state and in gastroesophageal reflux disease. Mast cells linked to IgE, which are not found in other conditions, have been identified in EE. Despite that fact, an anaphylactic reaction history after exposure to allergens is not common in these patients. Therefore, the mast cells' function in EE could be dependent on T lymphocytes, as suggested by a mast cell gene expression analysis. Bi-directional crosstalk is established between mast cells and eosinophils, hence establishing interesting hypotheses regarding their relationship to EE physiopathology. Mast cells' function as an immune response leader seems to substitute for their effector functions in EE, while at the same time opening new research pathways for consideration of these cells as a therapeutic target in EE. However, the inefficiency of therapies that inhibit mast cell functions while they are effective in other respiratory tract diseases results in the need for specific studies to identify the real function of such complex cells in the physiopathology of EE. There is indirect proof of the role of mast cells in EE, while many doubts exist about their activation mechanism, which does not seem to be IgE-mediated. Specific approach studies are needed to clarify the function of these cells in the physiopathology of EE, which could be a possible therapeutic target.

Eosinophilic esophagitis: the newest esophageal inflammatory disease

Eosinophilic esophagitis (EoE) is a chronic esophageal inflammatory disease of undetermined pathophysiology that results in dense mucosal eosinophilia and esophageal dysfunction. In childhood, vague symptoms associated with GERD and feeding difficulties are the first manifestations of EoE. Adults typically present with dysphagia and food impaction. No pathognomonic features have been identified for EoE and, therefore, its diagnosis must be made on both clinical and histological grounds. Effective treatments rely on steroids and dietary exclusions.

IL-33-activated dendritic cells induce an atypical TH2-type response

BACKGROUND

IL-33, a recently discovered IL-1 family cytokine, is implicated in the development of T(H)2-type responses in vivo. However, the cellular targets for IL-33 are poorly understood.

OBJECTIVE

We tested the hypotheses that dendritic cells (DCs) respond to IL-33 and that IL-33-activated DCs prime naive CD4(+) T cells to produce T(H)2-type cytokines.

METHODS

Dendritic cells were derived from mouse bone marrow, and their expression of the IL-33 receptor, ST2, was examined by fluorescence-activated cell sorting and real-time RT-PCR. The DCs' responses to IL-33 were examined by fluorescence-activated cell sorting (MHC-II and CD86 expression) and by ELISA (IL-6 and IL-12 production). The ability of IL-33-activated DCs to prime naive T cells was assessed by coculture with isolated CD4(+) T cells and by measuring cytokines in the supernatants.

RESULTS

ST2 mRNA was detectable in highly purified DCs. ST2 protein was abundant within DCs, but was barely detectable on their cell surfaces. Incubation of DCs with IL-33 increased their expression of MHC-II and CD86 and production of IL-6, but IL-12 was not produced. Anti-ST2 antibody inhibited IL-6 production from IL-33-activated DCs by approximately 60%; anti-ST2 did not affect IL-6 production from LPS-activated DCs. When incubated with naive CD4(+) T cells alone, IL-33 failed to stimulate cytokine production. In contrast, naive CD4(+) T cells incubated with IL-33-activated DCs showed robust production of IL-5 and IL-13, but IL-4 and IFN-gamma were undetectable.

CONCLUSION

Dendritic cells respond directly to IL-33 through ST2. The IL-33 and DC interaction may represent a new pathway to initiate T(H)2-type immune responses.

Seasonal distribution in newly diagnosed cases of eosinophilic esophagitis in adults

OBJECTIVES

The etiology of eosinophilic esophagitis (EoE) is not well understood. It has been proposed that eosinophils migrate to the esophagus in response to various ingested and inhaled allergens. Recent reports in children found an increased proportion of cases of EoE during months with higher outdoor aeroallergens. To our knowledge, this has not been evaluated in adults. We aimed to determine whether there is a seasonal distribution in the number of newly diagnosed cases of EoE in an adult population.

METHODS

We conducted a retrospective review of consecutive adult cases newly diagnosed with EoE in 1 year. Cases were grouped based on the index month when the diagnosis was made at endoscopy. To test the consistency of the observations, a second cohort of consecutive cases of similar sample size diagnosed at a different period in time was also analyzed.

RESULTS

In total, 41 patients were diagnosed with EoE at our center during the study period, providing an annual prevalence of 0.98%. More cases were diagnosed with EoE during the months of April and May than any other month (P<0.001). When patients were grouped seasonally, there was a significant increase of EoE cases in spring and summer months (n=28) when compared with the fall and winter months (n=13) (P=0.019). Analysis of the second cohort of cases (n=37) from 2002 to 2006 confirmed a similar seasonal diagnostic pattern for EoE during the outdoor seasons.

CONCLUSIONS

Our data demonstrate that EoE has a seasonal prevalence in adults. The seasonal variation pattern found in newly diagnosed EoE cases in adults supports the potential role of aeroallergens in the pathogenesis of EoE.

Immunopathological mechanisms of eosinophilic oesophagitis

BACKGROUND

Eosinophilic oesophagitis (EO) is a chronic inflammatory disease of the oesophagus, with an emergent character, defined by the presence of a dense infiltrate by eosinophilic leukocytes restricted to the mucosa of this organ after excluding gastro-oesophageal acid reflux. It is manifested by chronic and/or recurrent dysphagia and episodes of oesophageal alimentary impaction, with great variation in terms of intensity, frequency, and duration of the attacks.

METHODS

An Internet-based search was performed for the most recent articles with relevant information concerning immunopathological mechanisms involved in EO.

RESULTS

Bibliographical data allow us to define that EO is related to an allergic or hypersensitivity-induced reaction after exposure to foods or inhalants, with increased prevalence of sensitisation to these allergens. Data published up to now suggest a cellular hypersensitivity reaction rather than a humoral one in the physiopathology of EO. In this disease, sensitised T-lymphocytes mediate a Th2 type response, releasing cytokines such as IL-5, with a possible Th1 component that requires further investigation. The function of the abundant CD8+ T-lymphocytes present in the oesophageal epithelium has yet to be explained. Mast cells also participate in epithelial inflammatory infiltrate in EO, and it is still unknown if its activation, mainly through IgE, contributes to the immunopathology of the disease even though EO rarely manifests immediate hypersensitivity reactions. IL-5 and different forms of eotaxins perform an important active role in the recruitment of eosinophils to the oesophagus.

CONCLUSIONS

EO is an immunologically complex and little studied entity that is associated with other allergic diseases and in which different effector cells participate, determining an immunological response of cellular rather than a humoral hypersensitivity reaction. The data available point out that EO is a disorder of the Th2 retarded immune response, in which the triggering factor might not be IgE. Although the final inflammatory phenomena observed in EO are common for the different patients, the cascade of inflammatory mediators that lead to them might not be identical in all cases, and the morphological and functional disorders observed in EO would represent the final convergence of different activation forms of the mechanisms of inflammation.