Histologic eosinophilic gastritis is a systemic disorder associated with blood and extragastric eosinophilia, TH2 immunity, and a unique gastric transcriptome

Gene Expression Patterns in Distinct Endoscopic Findings for Eosinophilic Gastritis in Children

BACKGROUND

Eosinophilic gastritis (EG) is clinicopathologically characterized by both marked gastric eosinophilia and clinical symptoms. The endoscopic findings in EG vary among patients, leading to clinical confusion. However, little is known about the relationship between precise endoscopic findings and the pathophysiological process responsible for EG.

OBJECTIVE

We aimed to elucidate whether the gross endoscopic findings of EG can be classified into distinct gene expression profiles.

METHODS

We enrolled pediatric patients who underwent gastrointestinal endoscopy for clinical symptoms suggestive of eosinophilic gastrointestinal disorder between 2011 and 2016. EG was diagnosed when gastric eosinophilia was greater than or equal to 30 eosinophils/hpf. The gene expression profiles of gastric biopsies were assessed using microarray technology.

RESULTS

Patients with EG and control subjects (n = 8, each) were examined. On the microarray, 1,999 genes were differentially expressed between EG and the controls (≥2-fold difference, adjusted P value < .05), including significant upregulation of eotaxin-3 (C-C chemokine ligand 26). The endoscopic findings of patients with EG fell roughly into 2 types, namely, ulcerative and nodular lesions. Despite identifying distinct patterns of gene expression, most differentially regulated genes overlapped between the 2 endoscopic finding types. Several gene ontology terms were enriched in the substantially overlapped genes, but not in each of the distinct genes.

CONCLUSIONS

Our results strongly indicate that ulcerative and nodular lesions are a single disease, EG, or a variation thereof, in spite of morphological differences. Our findings may contribute to a better understanding of the pathogenesis of EG, as well as to more accurate diagnosis of this disease.

Profound loss of esophageal tissue differentiation in patients with eosinophilic esophagitis

BACKGROUND

A key question in the allergy field is to understand how tissue-specific disease is manifested. Eosinophilic esophagitis (EoE) is an emerging tissue-specific allergic disease with an unclear pathogenesis.

OBJECTIVE

Herein we tested the hypothesis that a defect in tissue-specific esophageal genes is an integral part of EoE pathogenesis.

METHODS

We interrogated the pattern of expression of esophagus-specific signature genes derived from the Human Protein Atlas in the EoE transcriptome and in EPC2 esophageal epithelial cells. Western blotting and immunofluorescence were used for evaluating expression of esophageal proteins in biopsy specimens from control subjects and patients with active EoE. Whole-exome sequencing was performed to identify mutations in esophagus-specific genes.

RESULTS

We found that approximately 39% of the esophagus-specific transcripts were altered in patients with EoE, with approximately 90% being downregulated. The majority of transcriptional changes observed in esophagus-specific genes were reproduced in vitro in esophageal epithelial cells differentiated in the presence of IL-13. Functional enrichment analysis revealed keratinization and differentiation as the most affected biological processes and identified IL-1 cytokines and serine peptidase inhibitors as the most dysregulated esophagus-specific protein families in patients with EoE. Accordingly, biopsy specimens from patients with EoE evidenced a profound loss of tissue differentiation, decreased expression of keratin 4 (KRT4) and cornulin (CRNN), and increased expression of KRT5 and KRT14. Whole-exome sequencing of 33 unrelated patients with EoE revealed 39 rare mutations in 18 esophagus-specific differentially expressed genes.

CONCLUSIONS

A tissue-centered analysis has revealed a profound loss of esophageal tissue differentiation (identity) as an integral and specific part of the pathophysiology of EoE and implicated protease- and IL-1-related activities as putative central pathways in disease pathogenesis.

Eosinophilic gastroenteritis: A state-of-the-art review

Eosinophilic gastrointestinal disorders are a series of diseases that include eosinophilic esophagitis, eosinophilic gastritis, eosinophilic gastroenteritis, eosinophilic enteritis, and eosinophilic colitis. Among these disorders, eosinophilic gastroenteritis is an uncommon and heterogeneous disease characterized by eosinophilic infiltration of the gastrointestinal tract in the absence of secondary causes, presenting with a variety of gastrointestinal manifestations. Up to now, epidemiology and pathophysiology of eosinophilic gastroenteritis are still unclear. Based on clinical manifestations and depth of eosinophilic infiltration into the gastrointestinal tract wall, eosinophilic gastroenteritis is classified into three different patterns including predominantly mucosal pattern, predominantly muscular pattern, and predominantly serosal pattern. For diagnosing eosinophilic gastroenteritis, it is necessary for clinicians to have a high degree of clinical suspicion. In addition to the gastrointestinal symptoms, other evidences such as laboratory results, radiological findings and endoscopy can also provide important diagnostic evidences for eosinophilic gastroenteritis. And these indirect pieces of information together with histological results will lead to a definitive diagnosis of eosinophilic gastroenteritis. To avoid specific allergen, dietary treatments can be considered as initial treatment strategy before drug treatment. Corticosteroids are the main medication for eosinophilic gastroenteritis and have a dramatic therapeutic efficacy. Yet other medications need to further verify their effects in clinical practice, and surgery should be avoided as far as possible.

Th2 Cells in Health and Disease

Helper T (Th) cell subsets direct immune responses by producing signature cytokines. Th2 cells produce IL-4, IL-5, and IL-13, which are important in humoral immunity and protection from helminth infection and are central to the pathogenesis of many allergic inflammatory diseases. Molecular analysis of Th2 cell differentiation and maintenance of function has led to recent discoveries that have refined our understanding of Th2 cell biology. Epigenetic regulation of Gata3 expression by chromatin remodeling complexes such as Polycomb and Trithorax is crucial for maintaining Th2 cell identity. In the context of allergic diseases, memory-type pathogenic Th2 cells have been identified in both mice and humans. To better understand these disease-driving cell populations, we have developed a model called the pathogenic Th population disease induction model. The concept of defined subsets of pathogenic Th cells may spur new, effective strategies for treating intractable chronic inflammatory disorders.

Novel Therapies for Eosinophilic Disorders

Current therapies for eosinophilic disorders are limited. Most treatment approaches remain empirical, are not supported by data from controlled clinical trials, involve the off-label use of agents developed for treatment of other diseases, and tend to rely heavily on the use of glucocorticoids and other agents with significant toxicity. Great progress has been made in the discovery, preclinical development, and clinical testing of a variety of biologics and small molecules that have the potential to directly or indirectly influence eosinophils, eosinophilic inflammation, and the consequences of eosinophil activation.

Facing Terminal Ileitis: Going Beyond Crohn's Disease

Terminal ileitis (TI) is an inflammatory condition of the terminal portion of the ileum that may occur acutely with right lower quadrant pain followed or not by diarrhea, or exhibit chronic obstructive symptoms and bleeding and normally it is associated to Crohn's disease (CD) although it may be associated to other different conditions. This review intended to contribute to a better understanding of TI in order to help in the diagnosis, medical approach and patient care. This work was performed on a survey of articles collected in different databases and a retrospective search was carried out to identify relevant studies in the field. Pathological conditions such as ulcerative colitis, the intake of non-steroidal anti-inflammatory drugs, infectious diseases, eosinophilic enteritis, malignant diseases, spondyloarthropathies, vasculitides, ischemia, sarcoidosis, amyloidosis and others may be related to ileitis but it is commonly referred to CD. To a correct therapeutic approach, it is necessary to understand the causes of this inflammation process. The performance of a clinical, laboratory, endoscopic, and histopathological evaluation of the individuals is crucial to the correct diagnosis and treatment once the inflammation of the ileum may occur due to different pathological conditions besides CD, leading to difficulties in the diagnosis. Thus, an individual approach is necessary once the correct diagnosis is crucial for the immediate therapeutic approach and recovering of the patient.

Wheat allergy: diagnosis and management

Triticum aestivum (bread wheat) is the most widely grown crop worldwide. In genetically predisposed individuals, wheat can cause specific immune responses. A food allergy to wheat is characterized by T helper type 2 activation which can result in immunoglobulin E (IgE) and non-IgE mediated reactions. IgE mediated reactions are immediate, are characterized by the presence of wheat-specific IgE antibodies, and can be life-threatening. Non-IgE mediated reactions are characterized by chronic eosinophilic and lymphocytic infiltration of the gastrointestinal tract. IgE mediated responses to wheat can be related to wheat ingestion (food allergy) or wheat inhalation (respiratory allergy). A food allergy to wheat is more common in children and can be associated with a severe reaction such as anaphylaxis and wheat-dependent, exercise-induced anaphylaxis. An inhalation induced IgE mediated wheat allergy can cause baker’s asthma or rhinitis, which are common occupational diseases in workers who have significant repetitive exposure to wheat flour, such as bakers. Non-IgE mediated food allergy reactions to wheat are mainly eosinophilic esophagitis (EoE) or eosinophilic gastritis (EG), which are both characterized by chronic eosinophilic inflammation. EG is a systemic disease, and is associated with severe inflammation that requires oral steroids to resolve. EoE is a less severe disease, which can lead to complications in feeding intolerance and fibrosis. In both EoE and EG, wheat allergy diagnosis is based on both an elimination diet preceded by a tissue biopsy obtained by esophagogastroduodenoscopy in order to show the effectiveness of the diet. Diagnosis of IgE mediated wheat allergy is based on the medical history, the detection of specific IgE to wheat, and oral food challenges. Currently, the main treatment of a wheat allergy is based on avoidance of wheat altogether. However, in the near future immunotherapy may represent a valid way to treat IgE mediated reactions to wheat.

Prevalence of Eosinophilic Gastritis, Gastroenteritis, and Colitis: Estimates From a National Administrative Database

OBJECTIVES

Eosinophilic esophagitis (EoE) is becoming increasingly more common, but the prevalence of other eosinophilic gastrointestinal disorders (EGIDs) is unknown. Our objective was to estimate the prevalence of eosinophilic gastritis, gastroenteritis, and colitis in the United States.

METHODS

We used the IMS Health LifeLink PharMetrics Plus Claims Database, data representative of a US national commercially insured population containing medical and pharmaceutical claims for > 75 million individuals. We restricted our sample to patients ages 0 to 64 with continuous enrollment between July 1, 2009, and June 30, 2011. We identified patients with eosinophilic gastritis, gastroenteritis, and colitis as defined by ≥ 1 instance of the International Classification of Diseases, Ninth Revision codes 535.70, 558.41, and 558.42, respectively. We calculated the prevalence of the codes in the database and then standardized the estimates to the US population by age and sex.

RESULTS

The standardized estimated prevalences of eosinophilic gastritis, gastroenteritis, and colitis were 6.3/100,000, 8.4/100,000, and 3.3/100,000, respectively. The prevalence of eosinophilic gastroenteritis was the highest among children age < 5 years, whereas eosinophilic gastritis was more prevalent among older age groups. We observed no age differences for eosinophilic colitis. Among affected patients, there was a high proportion of coexisting allergic conditions, 38.5% for eosinophilic gastritis, 45.6% for gastroenteritis, and 41.8% for colitis. Concomitant allergic disease was most commonly identified in pediatric patients.

CONCLUSIONS

The prevalence of non-EoE EGIDs remains rare in the United States, with < 50,000 total patients affected. There appears to be a female predominance and a high co-occurrence of atopic comorbidities.

Recent research advances in eosinophilic esophagitis

PURPOSE OF REVIEW

Eosinophilic esophagitis (EoE) is a chronic allergic disease triggered by food allergens with an increasing prevalence. This review highlights recent research advances in EoE with a focus on the literature of the past 18 months.

RECENT FINDINGS

The incidence of EoE in the black population is higher than previously suggested. A novel locus spanning CAPN14 is associated with EoE. Diagnostic tests utilizing an analysis of EoE-specific transcriptome have been improved. Standardized EoE symptom score systems have been established. Treatment trials show the promise and limitations of allergen avoidance, antiinflammatory reagents, and anti-interleukin-13 antibodies. Insights into disease mechanisms highlight the role of invariant natural killer T cells and group 2 innate immune cells. Epithelial barrier protein desmoglein 1, bone morphogenetic protein antagonist follistatin, neurotrophic tyrosine kinase receptor type 1, and CAPN14 have been defined as new potential therapeutic targets in EoE as regulators of the inflammatory interleukin-13-axis. The role of IgG4 in the disease mechanisms has been suggested.

SUMMARY

Genetic predisposition influenced by environmental factors increases EoE susceptibility. Research identifying the critical events leading to allergen sensitization and the esophagus-specific responses that drive EoE is evolving, and will lead to a better understanding of EoE and new therapeutic approaches for the disease.

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.

Altered STAT4 Isoform Expression in Patients with Inflammatory Bowel Disease

BACKGROUND

Crohn's disease (CD) and ulcerative colitis (UC) are the major forms of inflammatory bowel disease, and pathogenesis involves a complex interplay among genetic, environmental, and immunological factors. We evaluated isoform expression of the IL-12-activated transcription factor STAT4 in children with CD and UC.

METHODS

We collected biopsy samples from both patients newly diagnosed with CD and with UC. We further collected blood samples from patients newly diagnosed with CD and with UC as well as from patients who had a flare-up after being in clinical remission, and we examined the ratios of STAT4β/STAT4α mRNA. In addition to STAT4 isoforms, we measured the expression of the cytokines TNFα, IFNγ, granulocyte macrophage-colony stimulating factor, and IL-17 using polymerase chain reaction of biopsy samples and multiplex analysis of patient serum samples.

RESULTS

Ratios of STAT4β/STAT4α were increased in specific gastrointestinal tract segments in both patients with CD and those with UC that correlate with the location and severity of inflammation. In contrast, we did not observe changes in STAT4β/STAT4α ratios in biopsy specimens from patients with eosinophilic esophagitis. We also observed increased STAT4β/STAT4α ratios in the peripheral blood mononuclear cells of patients with UC and those with CD, compared with healthy controls. Ratios were normalized after patients were treated with steroids.

CONCLUSIONS

Collectively, these data indicate that STAT4 isoforms could be an important noninvasive biomarker in the diagnosis and treatment of inflammatory bowel disease and that expression of these isoforms might provide further insight into the pathogenesis of IBD.

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.

How I treat hypereosinophilic syndromes

Hypereosinophilic syndromes (HESs) are a group of rare disorders characterized by peripheral blood eosinophilia of 1.5 × 10(9)/L or higher and evidence of end organ manifestations attributable to the eosinophilia and not otherwise explained in the clinical setting. HESs are pleomorphic in clinical presentation and can be idiopathic or associated with a variety of underlying conditions, including allergic, rheumatologic, infectious, and neoplastic disorders. Moreover, the etiology of the eosinophilia in HESs can be primary (myeloid), secondary (lymphocyte-driven), or unknown. Although corticosteroids remain the first-line therapy for most forms of HESs, the availability of an increasing number of novel therapeutic agents, including tyrosine kinase inhibitors and monoclonal antibodies, has necessarily altered the approach to treatment of HESs. This review presents an updated treatment-based approach to the classification of patients with presumed HES and discusses the roles of conventional and novel agents in the management of these patients.

Eosinophils in Gastrointestinal Disorders: Eosinophilic Gastrointestinal Diseases, Celiac Disease, Inflammatory Bowel Diseases, and Parasitic Infections

The gastrointestinal (GI) tract provides an intriguing organ for considering the eosinophil's role in health and disease. The normal GI tract, except for the esophagus, is populated by eosinophils that are present throughout the mucosa, raising the possibility that eosinophils participate in innate mechanisms of defense. However, data from clinical studies associates increased numbers of eosinophils with inflammatory GI diseases, prompting concerns that eosinophils may have a deleterious effect on the gut. We present clinical features of 4 disease processes that have been associated with eosinophilia and suggest areas requiring investigation as to their clinical significance and scientific relevance.

Advances in allergic skin disease, anaphylaxis, and hypersensitivity reactions to foods, drugs, and insects in 2014

This review highlights some of the research advances in anaphylaxis; hypersensitivity reactions to foods, drugs, and insects; and allergic skin diseases that were reported in the Journal in 2014. Studies on food allergy suggest worrisomely high rates of peanut allergy and food-induced anaphylaxis-related hospitalizations. Evidence is mounting to support the theory that environmental exposure to peanut, such as in house dust, especially with an impaired skin barrier attributed to atopic dermatitis (AD) and loss of function mutations in the filaggrin gene, is a risk factor for sensitization and allergy. Diagnostic tests are improving, with early studies suggesting the possibility of developing novel cellular tests with increased diagnostic utility. Treatment trials continue to show the promise and limitations of oral immunotherapy, and mechanistic studies are elucidating pathways that might define the degree of efficacy of this treatment. Studies have also provided insights into the prevalence and characteristics of anaphylaxis and insect venom allergy, such as suggesting that baseline platelet-activating factor acetylhydrolase activity levels are related to the severity of reactions. Advances in drug allergy include identification of HLA associations for penicillin allergy and a microRNA biomarker/mechanism for toxic epidermal necrolysis. Research identifying critical events leading to skin barrier dysfunction and the polarized immune pathways that drive AD have led to new therapeutic approaches in the prevention and management of AD.

The management of eosinophilic gastroenteritis

Eosinophilic gastroenteritis (EG) is a rare disorder characterized by eosinophilic infiltration of the gastrointestinal tract. No medication at present is approved by the Food and drug administration of United States for the treatment of EG. The rarity of the disease limits our experience with the different management options. It also limits the ability to conduct randomized controlled trials that could clearly delineate the efficacy of new therapeutic agents. This review assesses the various management options that have been tried on patients with EG.