Immunophenotyping of peripheral eosinophils demonstrates activation in eosinophilic esophagitis

Eosinophil specialization is regulated by exposure to the esophageal epithelial microenvironment

Distinct subsets of eosinophils are reported in inflammatory and healthy tissues, yet the functions of uniquely specialized eosinophils and the signals that elicit them, particularly in eosinophilic esophagitis, are not well understood. Herein, we report an ex vivo system wherein freshly isolated human eosinophils were cocultured with esophageal epithelial cells and disease-relevant proinflammatory (IL-13) or profibrotic (TGF-β) cytokines. Compared with untreated cocultures, IL-13 increased expression of CD69 on eosinophils, whereas TGF-β increased expression of CD81, CD62L, and CD25. Eosinophils from IL-13-treated cocultures demonstrated increased secretion of GRO-α, IL-8, and macrophage colony-stimulating factor and also generated increased extracellular peroxidase activity following activation. Eosinophils from TGF-β-treated cocultures secreted increased IL-6 and exhibited increased chemotactic response to CCL11 compared with eosinophils from untreated or IL-13-treated coculture conditions. When eosinophils from TGF-β-treated cocultures were cultured with fibroblasts, they upregulated SERPINE1 expression and fibronectin secretion by fibroblasts compared with eosinophils that were cultured with granulocyte macrophage colony-stimulating factor alone. Translational studies revealed that CD62L was heterogeneously expressed by eosinophils in patient biopsy specimens. Our results demonstrate that disease-relevant proinflammatory and profibrotic signals present in the esophagus of patients with eosinophilic esophagitis cause distinct profiles of eosinophil activation and gene expression.

Models and Tools for Investigating Eosinophilic Esophagitis at the Bench

Eosinophilic esophagitis (EoE) is an increasingly common food allergy disease of the esophagus that received its medical designation code in 2008. Despite this recency, great strides have been made in the understanding of EoE pathophysiology and type 2 immunity through basic and translational scientific investigations conducted at the bench. These advances have been critical to our understanding of disease mechanisms and generating new hypotheses, however, there currently is only one very recently approved FDA-approved therapy for EoE, leaving a great deal to be uncovered for patients with this disease. Here we review some of the innovative methods, models and tools that have contributed to the advances in EoE discovery and suggest future directions of investigation to expand upon this foundation.

Case Report: Eosinophilic Esophagitis in a Patient With a Novel STAT1 Gain-of-Function Pathogenic Variant

Background

STAT1 gain-of-function (GOF) is a primary immune dysregulatory disorder marked by wide infectious predisposition (most notably chronic mucocutaneous Candidiasis), autoimmunity, vascular disease and malignant predisposition. While atopic features have been described in some STAT1 GOF patients, they are not considered a predominant feature of the disease. Additionally, while eosinophilic gastrointestinal infiltration has been reported in some cases, this has always been described in the context of pre-existing oropharyngeal and/or esophageal Candidiasis.

Clinical cases

Herein, we report 3 members of a multi-generational family diagnosed with STAT1 GOF caused by a novel mutation in the N-terminal domain, c.194A>C (p.D65A). The proband presented initially with a long-standing history of treatment-refractory eosinophilic esophagitis (EoE) without preceding gastrointestinal tract fungal infections, and her mother was diagnosed with esophagitis as well.

Conclusion

EoE has been previously associated with alterations to STAT6 and STAT3 signaling pathways. The current report expands the possible association between JAK/STAT-related disorders and EoE, suggesting that EoE could be a primary disease manifestation of STAT1 GOF, even in the absence of oropharyngeal and/or esophageal Candidiasis.

Association between abuse and neglect with functional constipation and irritable bowel syndrome in adolescents

OBJECTIVES

To evaluate the association between violence exposure, abuse, and neglect victimization with functional constipation and irritable bowel syndrome in adolescents.

METHODS

Observational cross-sectional case-control study conducted with adolescents from two public schools in the municipality of Osasco, metropolitan region of São Paulo, Brazil. A self-administered questionnaire validated for Brazilian Portuguese Child Abuse Screening Tools - Children's version (ICAST-C) was used to screen the different types of violence. The definition of functional constipation and irritable bowel syndrome was performed using the Rome IV criteria for adolescents. Parents or legal guardians completed the questionnaire for socioeconomic assessment and signed the informed consent form.

RESULTS

265 students aged 11-17 years, 157 females, were evaluated. Functional constipation and irritable bowel syndrome were found in 74 (27.9%) of the 265 adolescents. Violence exposure was found in 82.6% of the 265 screened adolescents, physical abuse in 91.3%, psychological abuse in 93.2%, sexual abuse in 12.1%, and neglect in 53.6%. The multiple logistic regression analysis showed an association (p < .05) between functional constipation and irritable bowel syndrome with violence exposure (OR = 2.77), physical abuse (OR = 2.17), psychological abuse (OR = 2.95), and neglect (OR= 2.31). There was no association with sexual abuse.

CONCLUSIONS

Functional constipation and irritable bowel syndrome were associated with violence exposure, physical abuse, psychological abuse, and neglect in adolescent students from public schools. No association was found with sexual abuse. Further studies are necessary to investigate the causal relationship between violence and functional gastrointestinal disorders.

Minimally invasive biomarker studies in eosinophilic esophagitis: A systematic review

BACKGROUND

Eosinophilic esophagitis (EoE) is a chronic, inflammatory disease of the esophagus that currently requires repeated endoscopic biopsies for diagnosis and monitoring because no reliable noninvasive markers have been identified.

OBJECTIVE

To identify promising minimally invasive EoE biomarkers and remaining gaps in biomarker validation.

METHODS

We performed a systematic review of EMBASE, Ovid MEDLINE, PubMed, and Web of Science from inception to June 6, 2017. Studies were included if patients met the 2007 consensus criteria for EoE diagnosis, a minimally invasive biomarker was assessed, and the study included at least 1 control for comparison.

RESULTS

The search identified 2094 studies, with 234 reviewed at full-text level, and 49 included in the analysis (20 adult, 19 pediatric, 7 pediatric and adult, and 3 not stated). Most (26 of 49) were published after 2014. Thirty-five studies included healthy controls, 9 analyzed atopic controls, and 29 compared samples from patients with active and inactive EoE. Minimally invasive biomarkers were obtained from peripheral blood (n = 41 studies), sponge or string samples (n = 3), oral or throat swab secretions (n = 2), breath condensate (n = 2), stool (n = 2), and urine (n = 2). The most commonly reported biomarkers were peripheral blood eosinophils (n = 16), blood and string eosinophil granule proteins (n = 14), and eosinophil surface or intracellular markers (n = 12). EoE biomarkers distinguished active EoE from healthy controls in 23 studies, atopic controls in 2 studies, and inactive EoE controls in 20 studies.

CONCLUSION

Several promising minimally invasive biomarkers for EoE have emerged; however, few are able to differentiate EoE from other atopic diseases.

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.

Differences in eosinophil molecular profiles between children and adults with eosinophilic esophagitis

BACKGROUND

Eosinophilic esophagitis (EoE) afflicts both children and adults. It has been debated whether pediatric EoE and adult EoE represent different disease entities. The objectives of this study were to determine whether the blood eosinophil molecular pattern of children with EoE is (i) distinct from that of healthy children; and (ii) different from that of adults with EoE.

METHODS

Blood eosinophils from children and adults with EoE, and healthy controls, were analyzed with flow cytometry regarding levels of CD23, CD44, CD54, CRTH2, FOXP3, and galectin-10. Eosinophil FOXP3 and galectin-10 mRNA levels were determined by qPCR. The data were analyzed using a multivariate method of pattern recognition.

RESULTS

An eosinophil molecular pattern capable of distinguishing children with EoE from control children was identified. A smaller fraction of eosinophils from children with EoE expressed CD44 and a larger fraction expressed CRTH2 than the controls. Eosinophils from children with EoE also had higher levels of galectin-10 mRNA and lower levels of FOXP3 mRNA. The eosinophils from children with EoE had lower levels of surface CD54 and of FOXP3 mRNA compared with the eosinophils from the adult patients. A key finding was the detection in healthy individuals of age-related differences in the levels of several eosinophil markers.

CONCLUSIONS

Children with EoE can be distinguished from healthy children based on the molecular patterns of their blood eosinophils. Age-related physiologic differences in eosinophil molecular patterns may partly explain the different blood eosinophil phenotypes in children vs adults with 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.

Clinical Applications of the Eosinophilic Esophagitis Diagnostic Panel

Eosinophilic esophagitis (EoE) is a recently recognized upper gastrointestinal allergic disorder characterized by esophageal dysfunction (e.g., dysphagia) and esophageal eosinophilia of ≥15 eosinophils/high-power field in patients who have persistent esophagitis even on proton pump inhibitor (PPI) therapy. The histologic method is the gold standard of EoE diagnosis. However, EoE clinical symptoms do not always correlate with histology, and the histologic method has sensitivity and specificity issues due to the patchiness of EoE and the subjective nature of the method. The “EoE transcriptome” was initially discovered in 2006, which led to the invention of the EoE diagnostic panel (EDP). In addition to providing a definitive EoE diagnosis with high accuracy, the EDP has been useful in elucidating several key elements about the disease including the efficacy of specific drugs such as swallowed glucocorticoids and anti-IL-13 humanized antibody therapy, the relationship between EoE and PPI-responsive esophageal eosinophilia, and predicting the disease course and responsiveness to therapy. The EDP’s long-term potential arises from its plasticity to incorporate new genes and uncover novel disease pathogenesis. We expect that the EDP will be increasingly helpful for personalized medicine approaches and improved diagnostics and disease monitoring.

Enhanced activation of eosinophils in peripheral blood and implications for eosinophilic esophagitis diagnosis

BACKGROUND AND AIM

Eosinophils are markers of the eosinophilic esophagitis (EoE) disease, and this work aimed to assess whether activation of eosinophils could be a noninvasive test to contribute for EoE diagnosis.

METHODS

The activation state of peripheral blood eosinophils in EoE patients and control subjects was assessed based on the morphological aspects of the eosinophil after adherence to slide. Cyclooxygenase-2 and 5-lipoxygenase expressions were evaluated by means of immunofluorescence microscopy to verify if and which eicosanoid pathway is triggered in eosinophils in blood in EoE.

RESULTS

The eosinophils of patients with EoE were significantly more activated than those of control individuals. The lowest percentage of normal eosinophils for control subjects was 40%, while the highest percentage of eosinophils of normal aspect for patients with EoE was 32%. Considering 36% as a cutoff for normal eosinophils, this value differentiated all individuals with EoE from individuals without the disease with a sensitivity of 100%, considering the diagnosis of EoE as currently defined. Eosinophils of EoE patients showed higher expression of cyclooxygenase-2 than those of control subjects.

CONCLUSIONS

The quantification of morphological changes in eosinophils is a feasible, easy, and reliable manner to identify EoE patients. Therefore, patients with symptoms of esophageal dysfunction showing higher than 36% activated eosinophils in peripheral blood could be a useful way to help definition and diagnostic criterion for EoE.

Biomarkers of the involvement of mast cells, basophils and eosinophils in asthma and allergic diseases

Biomarkers of disease activity have come into wide use in the study of mechanisms of human disease and in clinical medicine to both diagnose and predict disease course; as well as to monitor response to therapeutic intervention. Here we review biomarkers of the involvement of mast cells, basophils, and eosinophils in human allergic inflammation. Included are surface markers of cell activation as well as specific products of these inflammatory cells that implicate specific cell types in the inflammatory process and are of possible value in clinical research as well as within decisions made in the practice of allergy-immunology.

Eosinophilic Laryngitis in Children with Aerodigestive Dysfunction

Objective

To describe the presence of laryngeal eosinophils and associated symptomatology in patients with aerodigestive dysfunction.

Study Design

Case series with chart review.

Setting

Single tertiary pediatric referral center.

Subjects

Eighty-one consecutive pediatric patients referred to a multidisciplinary aerodigestive clinic with upper airway concerns.

Methods

Microlaryngoscopy and posterior arytenoid biopsy, flexible bronchoscopy, esophagogastroduodenoscopy and esophageal biopsy, and impedance probe testing were performed as indicated by clinical symptoms. Positive versus negative posterior arytenoid biopsy for eosinophils and the presence or absence of concomitant histopathological laryngitis and/or esophagitis were measured.

Results

Nine of 81 (11%) patients had positive laryngeal biopsy for eosinophils (range, 1-29 eosinophils/high-powered field [HPF]). Three of these 9 patients also had concurrent biopsy-proven eosinophilic esophagitis, while 8 of 81 total patients had biopsy-proven eosinophilic esophagitis. The frequency of biopsy-proven eosinophilic esophagitis was higher in patients with posterior arytenoid eosinophils versus patients without laryngeal eosinophils (33% versus 6.9%, P = .0408).

Conclusions

Eosinophilic inflammation in the larynx has not been described in children with complex aerodigestive complaints. Posterior arytenoid eosinophils may serve as a marker of chronic laryngeal inflammation in children with aerodigestive dysfunction, although their exact role in this inflammation remains unclear. In our population, >15 eosinophils/HPF within posterior arytenoid biopsies was associated with concomitant eosinophilic esophagitis.

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.

Non- and semi-invasive methods of monitoring eosinophilic esophagitis

BACKGROUND/AIMS

Monitoring inflammation associated with eosinophilic esophagitis (EoE) relies on the identification of biomarkers that provide an objective measure of disease activity. To date, this metric has been the number of eosinophils in the squamous epithelial tissue. The search for alternative biomarkers as well as alternative methods to capture them has been the topic of much research.

METHODS

Based on clinical experience and a review of the literature, the aim of this chapter is to identify potential EoE biomarkers and methods to assess them.

RESULTS

With respect to the biomarkers, a number of candidates have arisen, including peripheral blood eosinophils, eosinophil granule proteins, Th2-related cytokines and exhaled nitric oxide. Methods to assess these biomarkers have included peripheral blood, luminal lavages and breath collections.

CONCLUSIONS

Future research will identify the best clinical outcome measure for EoE. While mucosal eosinophilia currently serves as a well-defined metric of inflammation, newer research studies will continue to address whether this number correlates reliably with other patient-reported outcomes, endoscopic findings, molecular analyses or other yet to be defined biomarkers.