Eosinophilic gastrointestinal diseases--clinically diverse and histopathologically confounding

A Quantitative Assessment of Mucosal Eosinophils in the Gastrointestinal Tract of Children Without Detectable Organic Disease

BACKGROUND

Accurate measurements of mucosal eosinophil concentrations in gastrointestinal tracts of healthy children are necessary to differentiate health and disease states in general, and better define eosinophilic gastrointestinal diseases.

STUDY

We retrospectively reviewed gastrointestinal biopsies from children with macroscopically normal endoscopies, who, after a minimal follow-up of one year, were not diagnosed with any organic disease. Peak eosinophil concentrations and distributions were assessed from each segment of the gastrointestinal tract.

RESULTS

Three centers (Italy, United Kingdom, and Israel) contributed 202 patients (median age 13 years IQR 9.5-15.5, range 1-18 years). Median (IQR, range) eosinophil concentrations (eos/mm²) were: esophagus 0 (0-0, 0-84), stomach 0 (0-4, 0-84), duodenal bulb 20 (13-30, 7-67), second part of duodenum 20 (13-29, 0-105), terminal ileum 29 (14-51, 0-247), cecum 53 (37-89, 10-232), ascending colon 55 (25-84, 0-236), transverse colon 38 (21-67, 4-181), descending colon 29 (17-59, 0-114), sigmoid colon 25 (13-40, 0-215) and rectum 13 (4-28, 0-152). Significant geographical variance was present, however, no differences in eosinophil concentrations were identified between children with resolving symptoms vs. those with functional diagnoses, nor across age groups.

CONCLUSIONS

Standardized eosinophil concentrations from the gastrointestinal tracts of children without organic disease will serve to better define both health and disease states. No differences were found between resolved symptoms vs. functional diagnoses nor between age groups in this pediatric cohort.

Viral Induced Effects on a Vulnerable Epithelium; Lessons Learned From Paediatric Asthma and Eosinophilic Oesophagitis

The epithelium is integral to the protection of many different biological systems and for the maintenance of biochemical homeostasis. Emerging evidence suggests that particular children have epithelial vulnerabilities leading to dysregulated barrier function and integrity, that resultantly contributes to disease pathogenesis. These epithelial vulnerabilities likely develop in utero or in early life due to various genetic, epigenetic and environmental factors. Although various epithelia are uniquely structured with specific function, prevalent allergic-type epithelial diseases in children potentially have common or parallel disease processes. These include inflammation and immune response dysregulation stemming from atypical epithelial barrier function and integrity. Two diseases where aetiology and pathogenesis are potentially linked to epithelial vulnerabilities include Paediatric Asthma and Eosinophilic Oesophagitis (EoE). For example, rhinovirus C (RV-C) is a known risk factor for paediatric asthma development and is known to disrupt respiratory epithelial barrier function causing acute inflammation. In addition, EoE, a prevalent atopic condition of the oesophageal epithelium, is characterised by similar innate immune and epithelial responses to viral injury. This review examines the current literature and identifies the gaps in the field defining viral-induced effects on a vulnerable respiratory epithelium and resulting chronic inflammation, drawing from knowledge generated in acute wheezing illness, paediatric asthma and EoE. Besides highlighting the importance of epithelial structure and barrier function in allergic disease pathogenesis regardless of specific epithelial sub-types, this review focuses on the importance of examining other parallel allergic-type disease processes that may uncover commonalities driving disease pathogenesis. This in turn may be beneficial in the development of common therapeutics for current clinical management and disease prevention in the future.

Distribution of eosinophils in the gastrointestinal tract of children with no organic disease

Background

This study aimed to assess the eosinophil (eos) density of the mucosa of the gastrointestinal (GI) tract in children undergoing endoscopic procedures following an extensive workup, without diagnosis of an organic disease.

Methods

Biopsies from GI endoscopies performed at 3 major children’s hospitals (Athens, Madrid and Rome), between January 2012 and June 2018, were evaluated by a single pathologist in each center. Peak eos counts were expressed /high power field and /mm². Other histological abnormalities were also reported.

Results

A total of 111 children (median age 11 years; 48 boys) underwent upper endoscopy (333 biopsies), while 44 (median age 12; 25 boys) underwent ileocolonoscopy (262 biopsies). The median (interquartile range) eos/mm² were as follows: esophagus 0 (0-0); stomach 10.2 (3.3-15.3); duodenum 56.1 (26.1-86.7); ileum 61.2 (49.0-91.8); cecum 76.5 (40.9-99.7); ascending colon 73.9 (49.5-131.4); transverse colon 66.3 (40.8-91.5); descending colon 66.3 (30.6-81.6); sigmoid colon 39.2 (27.8-51.0); and rectum 25.5 (9.8-45.8). Geographical variations in GI tissue eos counts were found amongst the participating centers, but the causative factors need further evaluation. Functional GI disorders according to the Rome IV criteria were diagnosed in 73 children (37 boys, median age 13 years). No differences were found between children with or without functional GI disorder diagnosis, with regard to eos density in the GI tract.

Conclusion

The reported peak counts of GI tissue eos in children with no organic diseases provide normative values that may be useful in the evaluation of children with GI symptoms suggestive of eosinophilic GI disorders.

Impact of Gastroesophageal Reflux Disease on Mucosal Immunity and Atopic Disorders

Atopic disorders and gastroesophageal reflux disease (GERD) are some of the most common medical conditions treated by primary care physicians and specialists alike. The observation that atopic disorders, like asthma, allergic rhinitis and sinusitis, food allergies, atopic dermatitis, contact dermatitis, and eosinophilic esophagitis are common comorbidities in patients with GERD raises the question of the nature of the relationship that may exist between GERD and atopic disorders. In this article, we review the pathophysiology of GERD, its effect on the immune system, the effect of acid-blocking medications on allergic responses, as well as several common atopic conditions that have been associated with GERD including asthma, chronic rhinosinusitis (CRS), allergic rhinitis (AR), atopic dermatitis (AD), contact dermatitis (CD), food allergies, proton pump inhibitor (PPI)-responsive esophageal eosinophilia (PPI-REE), and eosinophilic esophagitis (EoE). In each condition, the evidence of a causal link is not definitive. Although the relationship between asthma and GERD remains controversial, evidence suggests that a subset of asthma patients with documented GERD may experience improved asthma control following appropriate treatment of GERD. The relationship of GERD to allergic rhinitis and chronic sinusitis is weak; however, studies support the concept that treatment of frequent episodes of GERD can have a positive effect on rhinitis and sinusitis overall. The relationship between allergic sensitization and GERD is likely bidirectional. GERD may induce changes in the mucosal immune system that may favor the development of food allergy and allergic sensitization to aeroallergens; however, the underlying mechanisms have not been established.

Non-IgE Mediated Food Allergy

Food allergies, defined as an immune response to food proteins, affect as many as 8% of young children and 2% of adults in western countries, and their prevalence appears to be rising like all allergic diseases. In addition to well-recognized urticaria and anaphylaxis triggered by IgE antibody- mediated immune responses, there is an increasing recognition of cell-mediated disorders, such as eosinophilic esophagitis and food protein-induced enterocolitis. Non-IgE-Mediated gastrointestinal food allergies are a heterogeneous group of food allergies in which there is an immune reaction against food but the primary pathogenesis is not a production of IgE and activation of mast cells and basophils. Those diseases tend to affect mainly the gastrointestinal tract and can present as acute (FPIES) or chronic reaction, such as Eosinophilic Esophagitis (EoE), Food Protein-Induced Allergic Proctocolitis (FPIAP). The role of food allergy in Non-EoE gastrointestinal Eosinophilic disorders (Non- EoE EGID) is poorly understood. In some diseases like EoE, T cell seems to play a major role in initiating the immunological reaction against food, however, in FPIES and FPIAP, the mechanism of sensitization is not clear. Diagnosis requires food challenges and/or endoscopies in most of the patients, as there are no validated biomarkers that can be used for monitoring or diagnosis of Non-IgE mediated food allergies. The treatment of Non-IgE food allergy is dependent on diet (FPIES, and EoE) and/or use of drugs (i.e. steroids, PPI) in EoE and Non-EoE EGID. Non-IgE mediated food allergies are being being investigated.

Phenotypes and endotypes in eosinophilic esophagitis

OBJECTIVE

To improve understanding of the heterogeneous presentation of eosinophilic esophagitis (EoE), and its different potential phenotypes and endotypes.

DATA SOURCES

We reviewed studies addressing EoE genetics, risks, natural history, treatment, phenotype, or endotype to assess data relating to differences in the presentation of EoE in children and adults. This review was restricted to articles in the English language.

STUDY SELECTIONS

Data source abstracts, pertinent articles, and book chapters meeting the objectives were critically reviewed.

RESULTS

Data to support differing phenotypes and endotypes in EoE are emerging, but findings are based on multiple studies and therefore sometimes incomparable. Like other atopic disorders EoE is a complex disease with diverse clinical presentations (phenotypes) based on response to therapy, natural history, and association with atopic comorbidities. Different pathogenetic mechanisms (endotypes) may drive the multiple phenotypes. T Helper type 2 inflammation, epithelial barrier defects, enhanced fibrosis, and association with rare monogenetic diseases are the most described endotypes in EoE.

CONCLUSION

Eosinophilic esophagitis is an atopic disorder that is increasing in prevalence and can be difficult to treat. Better understanding of phenotypes and endotypes in EoE may enable future care to be individualized more effectively, resulting in shorter time to remission and fewer endoscopies.

Pathophysiology of eosinophilic esophagitis: recent advances and their clinical implications

Introduction: Diagnostic and therapeutic strategies in eosinophilic esophagitis (EoE) are evolving. New knowledge regarding the pathophysiology of EoE has been the foundation for updated diagnostic recommendations and new therapeutic trials. Areas covered: We performed structured literature searches in Medline and PubMed, Cochrane meta-analyses, and abstracts of international congresses to review therapeutic approaches for EoE in July 2018. Additional articles were obtained by perusing the references of articles identified in the original PubMed search. Articles were excluded if they did not focus on the mechanism of disease, diagnosis, or treatment of humans with EoE. Expert commentary: Recent advances in the understanding of mechanisms underlying the pathology of EoE have resulted in significant change in the diagnostic algorithm for EoE, and are identifying promising potential targets for personalized medicine. There is a clinical need for improved targeted therapy for EoE, and better understanding the underlying pathophysiology of EoE will help to determine therapeutic targets. In this review, we highlight key mechanisms in the pathophysiology of EoE and how they are being utilized to change therapy in EoE.

Individuals affected by eosinophilic gastrointestinal disorders have complex unmet needs and frequently experience unique barriers to care

INTRODUCTION

Eosinophilic gastrointestinal disorders (EGIDs) are a rare but emerging healthcare problem. Patient advocacy groups (PAGs) have an important role in representing the EGID community, and serve as valuable research partners. By leveraging the partnership between medical researchers and PAGs, we examined the unmet needs and barriers to care perceived by individuals affected by EGIDs. Next, we examined if these varied between adult EGID patients and adult caregivers of children with EGID.

METHODS

Adult EGID patients and adult caregivers of children (<18 years) with EGIDs participated in this study. PAGs conducted focus groups comprised of individuals affected by EGIDs to identify domains and questions meaningful to the EGID community and this information was used to develop an online REDCap survey. The survey consisted of 58 questions across medical, healthcare, social, and emotional impact domains. It was distributed via the PAGs' web-based platforms. Demographic data, and responses to questions on a six-point Likert scale were collected and analyzed.

RESULTS

Of the 361 responses analyzed, 90 (25%) were from adult EGID patients and 271 (75%) were from adult caregivers. Of the applicable responses, in the medical domain only 19% of participants indicated that repeated endoscopies to monitor response to treatment was convenient. In the healthcare domain, 67% indicated that lack of insurance coverage for elemental formula was a barrier. In the social domain, only 5% of respondents reported adequate awareness of EGIDs in schools. In the emotional domain, 64% had experienced significant stress due to EGID related out-of-pocket costs. Multivariate logistic regression revealed that some of these responses varied between adult EGID patients and adult caregivers of children with EGID. The respondents indicated highest priority for improvement in the medical domain compared to other domains.

CONCLUSIONS

Individuals affected by EGIDs have a constellation of complex unmet needs and perceived barriers across medical, healthcare, social and emotional domains. Addressing unmet needs in the medical domain is relatively more important for the EGID community. Understanding unmet needs and barriers will likely help design improved patient-centered EGID care paradigms.

Eosinophilic Esophagitis Is an Underlying Cause for Gastrointestinal Concerns in Children

Eosinophilic esophagitis (EoE) is a chronic immune antigen-mediated disorder characterized by symptoms of esophageal dysfunction in combination with dense esophageal eosinophilia. The clinical presentation of EoE can vary depending on children's age and their ability to report symptoms, therefore a high index of suspicion for EoE is required because children and teenagers may develop coping strategies around eating. The development of symptoms measurement tools in EoE assists in not only assessing symptoms, but also coping strategies children may have developed. While the diagnosis of EoE requires endoscopic evaluation with histologic assessment of esophageal mucosal biopsy samples, several emerging methods to assess and survey the esophageal mucosa have been developed. Advances in the field to better understand the natural history, clinical and molecular features of phenotypes in EoE will be important in considering novel therapeutic options and assessing outcomes.

From genetics to treatment of eosinophilic esophagitis

PURPOSE OF REVIEW

Eosinophilic Esophagitis (EoE) is an emerging chronic atopic disease. Recent advances in understanding its genetic and molecular biology pathogenesis may lead to a better management of the disease

RECENT FINDINGS

EoE is an atopic disease. 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 n-IgE-mediated reaction to food and/or environmental allergens. Epidemiological studies show that EoE is an atopic disease with a strong genetic component. Genetic studies have shown that EoE is associated with single nucleotide polymorphism on genes, which are released by the epithelium and important in atopic inflammation such as thymic stromal lymphopoietin located (TSLP) close to the Th2 cytokine cluster [interleukin (IL)-4, IL-5, IL-13] on chromosome 5q22, Calpain 14, EMSY, and Eotaxin3. 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.

SUMMARY

EoE is treated like many other atopic diseases with a combination of topical steroids and/or food antigen avoidance. The new understanding of EoE may lead to more specific and definitive treatments of EoE.

Eosinophilic Esophagitis and Gastroenteritis

Eosinophilic gastrointestinal disease (EGID) can be classified as eosinophilic esophagitis (EoE) when the eosinophilia is limited to the esophagus or as eosinophilic gastritis (EG) if it is limited to the gastric tract, eosinophilic colitis (EC) if it is limited to the colon, and eosinophilic gastroenteritis (EGE) if the eosinophilia involves one or more parts of the gastrointestinal tract. EoE is by far the most common EGID. It is a well-defined chronic atopic disease due to a T helper type 2 (Th2) inflammation triggered often by food allergens. EoE diagnosis is done if an esophageal biopsy shows at least 15 eosinophils per high power field (eos/hpf). Globally accepted long-term therapies for EoE are the use of swallowed inhaled steroids or food antigen avoidance. The treatment of EoE is done not only to control symptoms but also to prevent complications such as esophageal stricture and food impaction. EGE cause non-specific gastrointestinal (GI) symptoms and are diagnosed if esophagogastroduodenoscopy (EGD)/colonoscopy show eosinophilia in one or more parts of the GI tract. They are rare diseases with an unclear pathogenesis, and they are poorly defined in terms of diagnostic criteria and treatment. Before initiating treatment of any EGE, it is imperative to conduct a differential diagnosis to exclude other causes of hypereosinophilia with GI localization. EGE are often poorly responsive to therapy and there is no commonly accepted long-term treatment. EG has many characteristics similar to EoE, including the fact that it is often due to a food allergen-driven Th2 inflammation; transcriptome analysis however shows that it is more a systemic disease and has a different gene signature than EoE. EC is a benign form of delayed food allergy in infant and is instead a difficult-to-treat severe inflammatory condition in older children and adults. EC in the latter groups can be a manifestation of drug allergy or autoimmune disease. Overall EGE, EC, and EG are rare and are a diagnosis of exclusion until more common causes of eosinophilia have been excluded.

Effect of glucocorticoid on expression of Eotaxin-3 in eosinophilic gastroenteritis

AIM: To detect the expression of eosinophil chemotactic factor-3 (Eotaxin-3) in eosinophilic gastroenteritis (EG) and investigate the effect of glucocorticoid on Eotaxin-3 expression.

METHODS: Forty-eight patients with EG and 24 healthy controls were included. Patients with EG were equally divided into two groups, a placebo group and a prednisone group. Eotaxin-3 expression was measured by enzyme-linked immunosorbent assay in the serum and tissue samples of all subjects.

RESULTS: The expression levels of Eotaxin-3 in serum and tissue were significantly elevated in the EG group compared to normal controls (P < 0.05). Eotaxin-3 in serum and tissue significantly decreased after treatment (P < 0.05), although its change had no significance in the placebo group. A positive correlation was observed between eosinophil (Eos) count and Eotaxin-3 in serum and tissue in the EG group.

CONCLUSION: Eotaxin-3 may be involved in the pathophysiological process of EG. Hormone therapy may inhibit the expression of Eotaxin-3. Serum Eotaxin-3 may be used as a non-invasive index for evaluating the treatment effect in EG.

BMP-driven NRF2 activation in esophageal basal cell differentiation and eosinophilic esophagitis

Tissue homeostasis requires balanced self-renewal and differentiation of stem/progenitor cells, especially in tissues that are constantly replenished like the esophagus. Disruption of this balance is associated with pathological conditions, including eosinophilic esophagitis (EoE), in which basal progenitor cells become hyperplastic upon proinflammatory stimulation. However, how basal cells respond to the inflammatory environment at the molecular level remains undetermined. We previously reported that the bone morphogenetic protein (BMP) signaling pathway is critical for epithelial morphogenesis in the embryonic esophagus. Here, we address how this pathway regulates tissue homeostasis and EoE development in the adult esophagus. BMP signaling was specifically activated in differentiated squamous epithelium, but not in basal progenitor cells, which express the BMP antagonist follistatin. Previous reports indicate that increased BMP activity promotes Barrett's intestinal differentiation; however, in mice, basal progenitor cell-specific expression of constitutively active BMP promoted squamous differentiation. Moreover, BMP activation increased intracellular ROS levels, initiating an NRF2-mediated oxidative response during basal progenitor cell differentiation. In both a mouse EoE model and human biopsies, reduced squamous differentiation was associated with high levels of follistatin and disrupted BMP/NRF2 pathways. We therefore propose a model in which normal squamous differentiation of basal progenitor cells is mediated by BMP-driven NRF2 activation and basal cell hyperplasia is promoted by disruption of BMP signaling in EoE.

Effectiveness of dietary allergen exclusion therapy on eosinophilic colitis in Chinese infants and young children ≤ 3 years of age

Eosinophilic colitis is a well recognized clinical entity mainly associated with food allergies. Empiric treatment options include dietary allergen exclusion (extensively hydrolyzed protein formula and elimination diet), anti-allergy medications (antihistamines and leukotriene receptor antagonists) and corticosteroids. We evaluated the effectiveness of dietary antigen exclusion on clinical remission of eosinophilic colitis in infants and young children. We retrospectively reviewed charts of all infants and children ≤3 years of age who were diagnosed with eosinophilic colitis (defined as mucosal eosinophilia ≥20 hpf⁻¹) from 1 January 2011 to 31 December 2013 at a tertiary children’s hospital in China. Forty-nine children were identified with eosinophilic colitis. Elemental formula, simple elimination diet or combination therapy resulted in clinical improvement in 75%, 88.2% and 80% of patients, respectively. In conclusion, eosinophilic colitis in infants and children ≤3 years of age responded well to dietary allergen exclusion.

Recent advances in the pathological understanding of eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a chronic allergen-mediated inflammatory disease of the esophagus. This inflammation leads to feeding difficulties, failure to thrive and vomiting in young children, and causes food impaction and esophageal stricture in adolescents and adults. In the 20 years since EoE was first described, we have gained a great deal of knowledge regarding the genetic predisposition of disease, the inflammatory milieu associated with EoE and the long-term complications of chronic inflammation. Herein, we summarize the important breakthroughs in the field including both in vitro and in vivo analysis. We discuss insights that we have gained from large-scale unbiased genetic analysis, a multitude of genetically and chemically altered mouse models of EoE and most importantly, the results of clinical trials of various pharmacologic agents. Understanding these successes and failures may be the key to developing more effective therapeutic strategies.

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.