Markers of antigen presentation and activation on eosinophils and T cells in the esophageal tissue of patients with eosinophilic esophagitis

Mechanistic Insights into Eosinophilic Esophagitis: Therapies Targeting Pathophysiological Mechanisms

Eosinophilic esophagitis (EoE) is a chronic inflammatory disease characterized by eosinophilic infiltration of the esophagus. It arises from a complex interplay of genetic predisposition (susceptibility loci), environmental triggers (allergens and dietary antigens), and a dysregulated immune response, mainly mediated by type 2 T helper cell (Th2)-released cytokines, such as interleukin (IL)-4, IL-5, and IL-13. These cytokines control eosinophil recruitment and activation as well as tissue remodeling, contributing to the characteristic features of EoE. The pathogenesis of EoE includes epithelial barrier dysfunction, mast cell activation, eosinophil degranulation, and fibrosis. Epithelial barrier dysfunction allows allergen penetration and promotes immune cell infiltration, thereby perpetuating the inflammatory response. Mast cells release proinflammatory mediators and promote eosinophil recruitment and the release of cytotoxic proteins and cytokines, causing tissue damage and remodeling. Prolonged inflammation can lead to fibrosis, resulting in long-term complications such as strictures and dysmotility. Current treatment options for EoE are limited and mainly focus on dietary changes, proton-pump inhibitors, and topical corticosteroids. Novel therapies targeting key inflammatory pathways, such as monoclonal antibodies against IL-4, IL-5, and IL-13, are emerging in clinical trials. A deeper understanding of the complex pathogenetic mechanisms behind EoE will contribute to the development of more effective and personalized therapeutic strategies.

Eosinophils induces glioblastoma cell suppression and apoptosis - Roles of GM-CSF and cysteinyl-leukotrienes

BACKGROUND

Glioblastoma is the most common and lethal primary brain tumor in adults. Despite the available cancer treatments, the recurrence of the tumor is high, and the survival rate is low. New approaches to antitumor therapies are needed. Eosinophils are prominent in allergic diseases and accumulate in several human brain tumors. Recently, the antitumor role of eosinophils has been targeted as eosinophils release several cytotoxic factors that induce cell impairment and death.

OBJECTIVE

Here we aim to evaluate the interaction of the eosinophil and glioblastoma cells, the mechanism involved in the potential killing of the glioblastoma cells by the eosinophils, and how allergy/asthma could confer a better glioblastoma prognosis.

METHODS

Eosinophils and serum from asthmatic and non-asthmatic donors were cultivated with different glioblastoma cell lines.

RESULTS

Glioblastoma cells recruit eosinophils via GM-CSF signaling, activating and increasing eosinophil survivability and function on a GM-CSF-dependent manner. Eosinophils reduce glioblastoma cells metabolism, proliferation, and migration, via Fas/FasL. Cysteinyl-leukotrienes are accounted for the asthmatic serum enhancement of the glioblastoma cell migration and proliferation. Cysteinyl-leukotrienes enhance glioblastoma cell proliferation and migration, albeit activate eosinophils that suppress glioblastoma cells.

CONCLUSION

Eosinophils have the potential to be key cells on glioblastoma therapeutics, as allergy and eosinophilia are correlated with a better glioblastoma prognosis. Eosinophils are elicited and attach to glioblastoma cells, where, by its cytotoxic function, via Fas/FasL, hind glioblastoma cell metabolism, proliferation, migration, and induce cell death.

Butyrate and propionate restore interleukin 13-compromised esophageal epithelial barrier function

BACKGROUND

Eosinophilic esophagitis (EoE) is a food allergen driven disease that is accompanied by interleukin (IL) 13 overexpression and esophageal barrier dysfunction allowing transepithelial food allergen permeation. Nutraceuticals, such as short-chain fatty acids (SCFAs) that restore barrier function and increase immune fitness may be a promising tool in the management of EoE. Here, we investigated the effects of the SCFAs acetate, propionate, and butyrate on an IL-13-compromised human esophageal epithelial barrier, including the mechanisms involved.

METHODS

An air-liquid interface culture model of differentiated human EPC2-hTERT (EPC2) was used to study whether SCFAs could restore barrier function after IL-13-induced impairment. Esophageal epithelial barrier function was monitored by transepithelial electrical resistance (TEER) and FITC-dextran paracellular flux, and was further examined by qPCR and immunohistochemical analysis. G protein-coupled receptor (GPR) GPR41, GPR43, GPR109a, or histone deacetylase (HDAC) (ant)agonists were used to assess mechanisms of action of SCFAs.

RESULTS

IL-13 stimulation decreased TEER and increased FITC flux, which was counteracted by butyrate and propionate, but not acetate treatment. Barrier proteins FLG and DSG1 mRNA expression was upregulated following butyrate and propionate treatment, whereas expression of eosinophil chemoattractant CCL26 and protease CAPN14 was downregulated. Similarly, butyrate and propionate restored FLG and DSG1 protein expression. Similar effects were observed with an HDAC antagonist but not with GPR agonists.

CONCLUSION

Nutraceuticals butyrate and propionate restore the barrier function of esophageal epithelial cells after an inflammatory insult and may be of therapeutic benefit in the management of EoE.

Toward a potential association between eosinophilic esophagitis and Klinefelter syndrome: a case series and review of the literature

Klinefelter syndrome (KS) is a sex aneuploidy abnormality comprised by one additional X chromosome. It occurs in 1:500-1000 male births. As with women, an increased susceptibility to autoimmune diseases is present. We report three cases of coexisting EoE and KS for a prevalence of 2% in our EoE clinic. Possible changes in gene expression in KS are reviewed, some of which may be related to activation of genes located on the X chromosome. We postulate that these X-activated genes in patients with KS yield a greater likelihood of developing EoE because of their genetic predisposition to autoimmune diseases.

Bidirectional crosstalk between eosinophils and esophageal epithelial cells regulates inflammatory and remodeling processes

Eosinophils accumulate adjacent to epithelial cells in the mucosa of patients with eosinophilic esophagitis (EoE), yet the bidirectional communication between these cells is not well understood. Herein, we investigated the crosstalk between human eosinophils and esophageal epithelial cells. We report that blood-derived eosinophils have prolonged survival when cocultured with epithelial cells; 96 ± 1% and 30 ± 6% viability was observed after 7 and 14 days of coculture, respectively, compared with 1 ± 0% and 0 ± 0% of monoculture. In the presence of IL-13 and epithelial cells, eosinophils had greater survival (68 ± 1%) at 14 days compared with cocultures lacking IL-13. Prolonged eosinophil viability did not require cellular contact and was observed when eosinophils were cultured in conditioned media from esophageal epithelial cells; neutralizing GM-CSF attenuated eosinophil survival. The majority of eosinophil transcripts (58%) were dysregulated in cocultured eosinophils compared with freshly isolated cells. Analysis of epithelial cell transcripts indicated that exposure to eosinophils induced differential expression of a subset of genes that were part of the EoE esophageal transcriptome. Collectively, these results uncover a network of crosstalk between eosinophils and esophageal epithelial cells involving epithelial mediated eosinophil survival and reciprocal changes in cellular transcripts, events likely to occur in EoE.

Impact of food challenge on local oesophageal immunophenotype in eosinophilic oesophagitis

BACKGROUND

Eosinophilic oesophagitis (EoE) is caused by the ingestion of food antigens. Dietary avoidance can result in clinical and histological remission, while food reintroduction can cause recurrence. It is uncertain if food antigen processing and immune activation occurs locally, in the oesophagus. Therefore, we performed a comparative study of the density of cell surface proteins (known to be involved with antigen presentation) on oesophageal tissue prior to, and following food antigen induced disease recurrence. A secondary aim was to consider novel biomarkers.

METHOD

Adult patients with a diagnosis of EoE, who had achieved histological remission with an elimination diet (<15 eosinophils per high power field at oesophageal biopsy), and who underwent food challenge with proven recurrence were included. Immunohistochemistry/immunofluorescence for CD1a, CD3, CD28, CD40, CD69, CD80, CD138, CXCR3 and HLA-DR was performed. Staining intensity of each biomarker (pixels/mm² ) was quantified by semi-automated analysis (Studio-FL software).

RESULTS

Fourteen cases of EoE (pre and post food challenge), 6 GORD and 5 healthy controls were included. HLA-DR, CD3, CD28, CD40 and CD 138 significantly increased with food reintroduction (P = <0.05). CD1a, CD 69, CD 80 and CXCR3 did not measurably change.

CONCLUSION

The presence of cell surface proteins typically associated with antigen presentation (following food antigen induced recurrence) suggests immune activation occurs in the oesophagus, and the relative lack of langerhans cells (CD1a) may indicate this cell type is unimportant. The cell surface protein CD 138 increases with disease recurrence, is not elevated in GORD or healthy controls, and has promise as a biomarker.

Eosinophils in Eosinophilic Esophagitis: The Road to Fibrostenosis is Paved With Good Intentions

Eosinophilic esophagitis (EoE) is an antigen-driven disease associated with epithelial barrier dysfunction and chronic type 2 inflammation. Eosinophils are the defining feature of EoE histopathology but relatively little is known about their role in disease onset and progression. Classically defined as destructive, end-stage effector cells, eosinophils (a resident leukocyte in most of the GI tract) are increasingly understood to play roles in local immunity, tissue homeostasis, remodeling, and repair. Indeed, asymptomatic esophageal eosinophilia is observed in IgE-mediated food allergy. Interestingly, EoE is a potential complication of oral immunotherapy (OIT) for food allergy. However, we recently found that patients with peanut allergy may have asymptomatic esophageal eosinophilia at baseline and that peanut OIT induces transient esophageal eosinophilia in most subjects. This is seemingly at odds with multiple studies which have shown that EoE disease severity correlates with tissue eosinophilia. Herein, we review the potential role of eosinophils in EoE at different stages of disease pathogenesis. Based on current literature we suggest the following: (1) eosinophils are recruited to the esophagus as a homeostatic response to epithelial barrier disruption; (2) eosinophils mediate barrier-protective activities including local antibody production, mucus production and epithelial turnover; and (3) when type 2 inflammation persists, eosinophils promote fibrosis.

Recent advances in potential targets for eosinophilic esophagitis treatments

Introduction: Diagnostic and therapeutic strategies in eosinophilic esophagitis (EoE) are constantly evolving. Recently, the improved understanding of EoE pathogenesis has led to identification of a variety of other potential targets that have never been considered before.Areas covered: In September 2019, we performed structured literature searches in Medline and PubMed, Cochrane meta-analyses, and abstracts of international congresses to review new potential therapeutic approaches for EoE.Expert opinion: The advent of omics disciplines has been helping in finding new molecular targets in EoE pathogenesis and may provide future guidance for deep phenotyping of the disease and therefore facilitate the possibility of personalized medicine. Interestingly, these new treatments should be focused on the restoration of epithelial barrier dysfunction, downregulation of specific molecular pathways of eosinophilic inflammation, and finally, prevention of esophageal remodeling. In this review, we highlight the most recent insights in EoE pathogenesis, which open new pathways for developing new therapeutic targets for clinical practice.

The Role of Eosinophils in Bullous Pemphigoid: A Developing Model of Eosinophil Pathogenicity in Mucocutaneous Disease

Bullous pemphigoid (BP) is an autoimmune blistering disease which carries a significant mortality and morbidity. While historically BP has been characterized as an IgG driven disease mediated by anti-BP180 and BP230 IgG autoantibodies, developments in recent years have further elucidated the role of eosinophils and IgE autoantibodies. In fact, eosinophil infiltration and eosinophilic spongiosis are prominent features in BP. Several observations support a pathogenic role of eosinophils in BP: IL-5, eotaxin, and eosinophil-colony stimulating factor are present in blister fluid; eosinophils line the dermo-epidermal junction (DEJ) in the presence of BP serum, metalloprotease-9 is released by eosinophils at the site of blisters; eosinophil degranulation proteins are found on the affected basement membrane zone as well as in serum corresponding with clinical disease; eosinophil extracellular DNA traps directed against the basement membrane zone are present, IL-5 activated eosinophils cause separation of the DEJ in the presence of BP serum; and eosinophils are the necessary cell required to drive anti-BP180 IgE mediated skin blistering. Still, it is likely that eosinophils contribute to the pathogenesis of BP in numerous other ways that have yet to be explored based on the known biology of eosinophils. We herein will review the role of eosinophils in BP and provide a framework for understanding eosinophil pathogenic mechanisms in mucocutaneous disease.

Resident intestinal eosinophils constitutively express antigen presentation markers and include two phenotypically distinct subsets of eosinophils

Intestinal eosinophils are implicated in homeostatic and disease-associated processes, yet the phenotype of intestinal tissue-dwelling eosinophils is poorly defined and their roles in intestinal health or disease remain enigmatic. Here we probed the phenotype and localization of eosinophils constitutively homed to the small intestine of naive mice at baseline, and of antigen-sensitized mice following intestinal challenge. Eosinophils homed to the intestinal lamina propria of naive mice were phenotypically distinguished from autologous blood eosinophils, and constitutively expressed antigen-presenting cell markers, suggesting that intestinal eosinophils, unlike blood eosinophils, may be primed for antigen presentation. We further identified a previously unrecognized resident population of CD11chi eosinophils that are recovered with intraepithelial leucocytes, and that are phenotypically distinct from both lamina propria and blood eosinophils. To better visualize intestinal eosinophils in situ, we generated eosinophil reporter mice wherein green fluorescent protein expression is targeted to both granule-delimiting and plasma membranes. Analyses of deconvolved fluorescent z-section image stacks of intestinal tissue sections from eosinophil reporter mice revealed eosinophils within intestinal villi exhibited dendritic morphologies with cellular extensions that often contacted the basement membrane. Using an in vivo model of antigen acquisition in antigen-sensitized mice, we demonstrate that both lamina propria-associated and intraepithelium-associated eosinophils encounter, and are competent to acquire, lumen-derived antigen. Taken together these data provide new foundational insights into the organization and functional potential of intestinal tissue-dwelling eosinophils, including the recognition of different subsets of resident intestinal eosinophils, and constitutive expression of antigen-presenting cell markers.

Eosinophilic Esophagitis: Pathophysiology and Definition

Eosinophilic esophagitis is an adaptive immune response to patient-specific antigens, mostly foods. Eosinophilic esophagitis is not solely IgE-mediated and is likely characterized by Th2 lymphocytes with an impaired esophageal barrier function. The key cytokines and chemokines are thymic stromal lymphopoeitin, interleukin-13, CCL26/eotaxin-3, and transforming growth factor-β, all involved in eosinophil recruitment and remodeling. Chronic food dysphagia and food impactions, the feared late complications, are related in part to dense subepithelial fibrosis, likely induced by interleukin-13 and transforming growth factor-β.

Functions of tissue-resident eosinophils

Eosinophils are a prominent cell type in particular host responses such as the response to helminth infection and allergic disease. Their effector functions have been attributed to their capacity to release cationic proteins stored in cytoplasmic granules by degranulation. However, eosinophils are now being recognized for more varied functions in previously underappreciated diverse tissue sites, based on the ability of eosinophils to release cytokines (often preformed) that mediate a broad range of activities into the local environment. In this Review, we consider evolving insights into the tissue distribution of eosinophils and their functional immunobiology, which enable eosinophils to secrete in a selective manner cytokines and other mediators that have diverse, 'non-effector' functions in health and disease.

Management of Eosinophilic Esophagitis Based on Pathophysiological Evidence

Over the past decades eosinophilic esophagitis (EoE) has been increasingly diagnosed, and significant progress has been made in our understanding of its pathophysiology. As EoE cannot be cured yet, treatment goals are suppression of disease activity and symptoms as well as the prevention of progression to a more severe disease phenotype. Disease-modifying treatment options can be divided into dietary therapy and immunosuppressive medications, of which topical steroids have been most investigated, yet are still prescribed off-label. In this review, we will summarize recent advances in our understanding of EoE and discuss the mechanisms of action of current treatment options, with emphasis on the role of the esophageal epithelial barrier and the effects of proton-pump inhibitors in the management of patients with EoE.

Eosinophils from eosinophilic oesophagitis patients have T cell suppressive capacity and express FOXP3

Eosinophilic esophagitis (EoE) is an antigen-driven T cell-mediated chronic inflammatory disease where food and environmental antigens are thought to have a role. Human eosinophils express the immunoregulatory protein galectin-10 and have T cell suppressive capacity similar to regulatory T cells (Tregs ). We hypothesized that one function of eosinophils in EoE might be to regulate the T cell-driven inflammation in the oesophagus. This was tested by evaluating the suppressive capacity of eosinophils isolated from the blood of adult EoE patients in a mixed lymphocyte reaction. In addition, eosinophilic expression of forkhead box protein 3 (FOXP3), the canonical transcription factor of Tregs , was determined by conventional and imaging flow cytometry, quantitative polymerase chain reaction (qPCR), confocal microscopy and immunoblotting. It was found that blood eosinophils from EoE patients had T cell suppressive capacity, and that a fraction of the eosinophils expressed FOXP3. A comparison of EoE eosinophils with healthy control eosinophils indicated that the patients' eosinophils had inferior suppressive capacity. Furthermore, a higher percentage of the EoE eosinophils expressed FOXP3 protein compared with the healthy eosinophils, and they also had higher FOXP3 protein and mRNA levels. FOXP3 was found in the cytosol and nucleus of the eosinophils from both the patients and healthy individuals, contrasting with the strict nuclear localization of FOXP3 in Tregs . To conclude, these findings suggest that the immunoregulatory function of eosinophils may be impaired in EoE.

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.

Lymphocytic oesophagitis, eosinophilic oesophagitis and compound lymphocytic-eosinophilic oesophagitis I: histological and immunohistochemical findings

AIMS

To report four histological-immunohistochemical oesophagitis phenotypes.

METHODS

Oesophageal biopsies from 311 patients were stained with H&E and with CD3, a T cell marker. Additional immunohistochemical stains (n=413) were performed in 77 cases.

RESULTS

Four histological-immunohistochemical oesophagitis phenotypes were recorded: lymphocytic oesophagitis (LyE, ≥40 CD3+ lymphocytes/HPF in CD3 immunostain), eosinophilic oesophagitis (EoE, ≥15 eosinophils/HPF in H&E stain), lymphocytic infiltration (≤39 CD3+/HPF) and compound lymphocytic oesophagitis-eosinophilic oesophagitis (Co LyE-EoE). At index biopsy, 28.3% (n=88) had LyE, 21.2% (n=66) EoE, 10.6% (n=33) Co LyE-EoE and 39.9% (n=124) lymphocytic infiltration. A persistent oesophagitis phenotype was found in 42.5% (37/87) in the first follow-up biopsy, in 34.4% (21/61) in the second follow-up biopsy and in 48.1% (26/54) in the third follow-up biopsy. Using βF1 immunostain, two different surface T cell receptors were detected in LyE and Co Lye-EoE: one having ≥40 βF1+/HPF (βF1+ high) and the other having <39 βF1+/HPF (βF1+ low).

CONCLUSIONS

Based on the literature regarding the significance of intraepithelial lymphocytes (IELs) in the initiation of EoE, we submit that the IEL phenotypes in LyE might differ from those found in EoE as they were unable to elicit the same eosinophilic response. Recent studies disclosed that group 2 innate lymphocytes (ILC2s), enriched in EoE, remain undetected in CD3 immunostain as they lack surface markers for T, B, natural killer (NK) or NK T cells. If ILC2s also participate in the lymphocytic infiltration of EoE, then the frequency of cases with Co LyE-EoE here reported might have been much higher. The four oesophagitis phenotypes described are easy to recognise, provided that the dual staining procedure (H&E-CD3) is implemented.

The Immunologic Mechanisms of Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) is a chronic allergic inflammatory disease that is triggered by food and/or environmental allergens and is characterized by a clinical and pathologic phenotype of progressive esophageal dysfunction due to tissue inflammation and fibrosis. EoE is suspected in patients with painful swallowing, among other symptoms, and is diagnosed by the presence of 15 or more eosinophils per high-power field in one or more of at least four esophageal biopsy specimens. The prevalence of EoE is increasing and has now reached rates similar to those of other chronic gastrointestinal disorders such as Crohn's disease. In recent years, our understanding of the immunologic mechanisms underlying this condition has grown considerably. Thanks to new genetic, molecular, cellular, animal, and translational studies, we can now postulate a detailed pathway by which exposure to allergens results in a complex and coordinated type 2 inflammatory cascade that, if not intervened upon, can result in pain on swallowing, esophageal strictures, and food impaction. Here, we review the most recent research in this field to synthesize and summarize our current understanding of this complex and important disease.

Allergic mechanisms of Eosinophilic oesophagitis

Eosinophilic oesophagitis (EoE) is characterized by oesophageal dysfunction and oesophageal eosinophilia refractory to proton-pump-inhibitor treatment. EoE is a food allergy, as elimination of food trigger(s) abrogates the disease, while trigger reintroduction causes recurrence. The allergic mechanism of EoE involves both IgE and non-IgE processes. There is a break in oral tolerance, the immune mechanism allowing enteric exposure to food and micro-organisms without causing deleterious immune responses. Changes in life-style, alterations in gut flora and use of antibiotics may be increasing disease prevalence. Mouse models of EoE and human studies revealed the role of regulatory T-cells and iNKT-cells in the pathogenesis. Th2-cytokines like IL-4, IL-5 and IL-13, and other cytokines like TGFβ and TSLP are involved, but perhaps no one cytokine is critically important for driving the disease. Control of EoE may require a pharmaceutical approach that blocks more than one target in the Th2-inflammatory pathway.

Topical corticosteroids do not revert the activated phenotype of eosinophils in eosinophilic esophagitis but decrease surface levels of CD18 resulting in diminished adherence to ICAM-1, ICAM-2, and endothelial cells

Swallowed topical corticosteroids are the standard therapy for eosinophilic esophagitis (EoE) in adults. Eosinophils in the blood of untreated EoE patients have an activated phenotype. Our aim was to determine if corticosteroids restore the phenotype of eosinophils to a healthy phenotype and if certain cell-surface molecules on blood eosinophils correlate with eosinophilic infiltration of the esophagus. Levels of eight surface markers on eosinophils from treated and untreated EoE patients were determined by flow cytometry and analyzed using multivariate methods of pattern recognition. Corticosteroid-treated EoE patients' eosinophils had decreased levels of CD18 compared to both untreated patients and healthy controls, but maintained their activated phenotype. CD18 expression correlated positively with eosinophil numbers in the esophagus and promoted the adherence of eosinophils to ICAM-1, ICAM-2, and to endothelial cells. The diminished expression of CD18 may be one mechanism behind the reduced entry of eosinophils into the esophagus in corticosteroid-treated EoE patients.

A pilot study of omalizumab in eosinophilic esophagitis

Eosinophilic disorders of the gastrointestinal tract are an emerging subset of immune pathologies within the spectrum of allergic inflammation. Eosinophilic Esophagitis (EoE), once considered a rare disease, is increasing in incidence, with a rate of over 1 in 10,000 in the US, for unknown reasons. The clinical management of EoE is challenging, thus there is an urgent need for understanding the etiology and pathophysiology of this eosinophilic disease to develop better therapeutic approaches. In this open label, single arm, unblinded study, we evaluated the effects of an anti-IgE treatment, omalizumab, on local inflammation in the esophagus and clinical correlates in patients with EoE. Omalizumab was administered for 12 weeks to 15 subjects with long standing EoE. There were no serious side effects from the treatment. Esophageal tissue inflammation was assessed both before and after therapy. After 3 months on omalizumab, although tissue Immunoglobulin E (IgE) levels were significantly reduced in all but two of the subjects, we found that full remission of EoE, which is defined as histologic and clinical improvement only in 33% of the patients. The decrease in tryptase-positive cells and eosinophils correlated significantly with the clinical outcome as measured by improvement in endoscopy and symptom scores, respectively. Omalizumab-induced remission of EoE was limited to subjects with low peripheral blood absolute eosinophil counts. These findings demonstrate that in a subset of EoE patients, IgE plays a role in the pathophysiology of the disease and that anti-IgE therapy with omalizumab may result in disease remission. Since this study is open label there is the potential for bias, hence the need for a larger double blind placebo controlled study. The data presented in this pilot study provides a foundation for proper patient selection to maximize clinical efficacy.

Translating new developments in eosinophilic esophagitis pathogenesis into clinical practice

OPINION STATEMENT

New developments in eosinophilic esophagitis (EoE) pathogenesis are shaping our current therapeutic and management strategies. EoE is a chronic allergic inflammatory disease with progression to fibrostenotic disease. The disease warrants early diagnosis and long-term maintenance therapy. The diagnosis of EoE should be based on the concept of an allergy-mediated disease with esophageal dysfunction and esophageal eosinophilia. Recent findings suggest that proton pump inhibitor (PPI)-responsive esophageal eosinophilia (PPI-REE) is likely a continuum of EoE or a similar T-helper 2 (Th2)-mediated allergic process. PPIs have therapeutic properties that can benefit both gastroesophageal reflux disease (GERD) and EoE. Therefore, PPIs should be considered not a diagnostic tool but, rather, a therapeutic option for EoE. If patients are PPI nonresponsive, then dietary therapy or steroid therapy should be considered. Dilation can be reserved as adjuvant therapy for severe fibrostenotic lesions.

Accuracy of liquid cytology in the diagnosis and monitoring of eosinophilic oesophagitis

BACKGROUND

Oesophagoscopy with biopsy is considered the gold standard for diagnosing and monitoring eosinophilic oesophagitis (EoE). Therefore is important to discover less-invasive diagnostic methods.

METHODS

Cytology specimens were obtained in patients with active EoE (AEoE) (≥15 eos/hpf) and EoE in remission (EoER) (<15 eos/hpf). The samples were assessed by two independent pathologists and were compared with biopsy samples. EoE cytology specimens were compared with specimens obtained from patients with GERD.

RESULTS

Specimens of 36 patients (69.4% male, mean age 30.88 years) were included. AEoE (17, 47.2%), EoER (11, 30.5%) and GERD (22.2%). eos/hpf in cytology (AEoE 9.23 vs. EoER 1.54 vs. GERD 2, p = 0.01). Linear correlation between eos/hpf average biopsy and cytology eos/hpf: r = 0.57, p < 0.001. For diagnosis of EoE ≥3 eos/hpf in cytology obtained a sensitivity of 70%, specificity 81%, PPV 86% and NPV 60% (AUC = 0.81, p = 0.01). For detection of AEoE, ≥3 eos/hpf in LBC obtained a sensitivity of 70%, specificity 82%, PPV 81% and NPV 66% (AUC = 0.87, p = 0.001).

CONCLUSIONS

LBC in oesophageal aspirate seems to be effective for the diagnosis and monitoring activity in EoE. These results support the usefulness of non-invasive methods for the diagnosis and monitoring of EoE.

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.

T cell co-stimulatory molecules: a co-conspirator in the pathogenesis of eosinophilic esophagitis?

Eosinophilic esophagitis (EoE) has become a common gastrointestinal disease. It is characterized by severe eosinophil infiltration in the esophagus. EoE is strongly associated with food allergy, asthma, atopic dermatitis, and other allergic diseases. T lymphocytes, especially Th2 cells, play an instrumental role in the development of allergic inflammation. Recent studies have shown that the ligation of co-stimulatory molecules contributes to the activation, differentiation, and proliferation of T cells. In this review, we will discuss the growing evidence of co-stimulatory molecules including OX40, Light, and HVEM in the pathogenesis of Th2-driven EoE. Our goal is to provide the rationale for the development of novel therapy therapies that target co-stimulatory molecules.