Treatment-resistant eosinophilic oesophagitis successfully managed with tofacitinib

Development and dysfunction of structural cells in eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a disorder characterized by dysfunction and chronic local inflammation of the esophagus. The incidence and prevalence of EoE are increasing worldwide. The mechanisms responsible are poorly understood, and effective treatment options are limited. From the lumen outward, the esophagus comprises stratified squamous epithelium, lamina propria, and muscle. The tissue-specific nature of EoE strongly suggests that structural cells in the esophagus are involved in the EoE diathesis. Epithelial basal cell hyperplasia and dilated intercellular spaces are cardinal features of EoE. Some patients with EoE develop lamina propria fibrosis, strictures, or esophageal muscle dysmotility. Clinical symptoms of EoE are only weakly correlated with peak eosinophil count, implying that other cell types contribute to EoE pathogenesis. Epithelial, endothelial, muscle, and fibroblast cells can each initiate inflammation and repair, regulate tissue resident immune cells, recruit peripheral leukocytes, and tailor adaptive immune cell responses. A better understanding of how structural cells maintain tissue homeostasis, respond to cell-intrinsic and cell-extrinsic stressors, and exacerbate and/or resolve inflammatory responses in the esophagus is needed. This knowledge will facilitate the development of more efficacious treatment strategies for EoE that can restore homeostasis of both hematopoietic and structural elements in the esophagus.

Pharmacologic Management of Eosinophilic Esophagitis

Proton pump inhibitors (PPIs), swallowed topical corticosteroids (STSs), and dupilumab are highly effective therapies for the treatment of eosinophilic esophagitis. Shared decision-making informs the choice of therapy and factors such as ease of use, safety, cost, and efficacy should be addressed. PPIs are the most common medication utilized early in the disease course; however, for nonresponders, STSs are an excellent alternative. Dupilumab is unlikely to replace PPIs or STSs as first-line therapy, except in highly specific circumstances. Identification of novel biologic pathways and the development of small molecules may lead to a wider range of treatment options in the future.

Dupilumab-Associated Arthritis: A Dermatology-Rheumatology Perspective

Dupilumab is an interleukin (IL)-4/13 inhibitor approved by the US FDA for multiple atopic indications. It is well-known to have favorable efficacy and safety profiles; however, emerging reports of dupilumab-associated arthritis suggest an underrecognized potential adverse effect. In this article, we summarize the literature to date to better characterize this clinical phenomenon. Arthritic symptoms were most commonly peripheral, generalized, and symmetric. Onset was generally within 4 months following initiation of dupilumab, and most patients resolved fully after a matter of weeks following discontinuation. Mechanistic insights suggest that suppression of IL-4 may lead to increased activity of IL-17, a prominent cytokine in inflammatory arthritis. We propose a treatment algorithm that stratifies patients by severity, recommending that patients with more mild disease continue dupilumab and treat through symptoms, while patients with more severe disease discontinue dupilumab and consider switching to another class (e.g., Janus kinase inhibitors). Lastly, we discuss important ongoing questions that should be addressed in future studies.

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.

Current and Novel Therapies for Eosinophilic Gastrointestinal Diseases

Eosinophilic gastrointestinal diseases (EGIDs) are an emerging group of pathological entities characterized by an eosinophil-predominant infiltration of different tracts of the gut in the absence of secondary causes of eosinophilia. According to the specific tract of the gut involved, EGIDs can be classified into eosinophilic esophagitis (EoE), eosinophilic gastritis (EoG), eosinophilic enteritis (EoN), and eosinophilic colitis (EoC). The epidemiology of EGIDs is evolving rapidly. EoE, once considered a rare disease, now has an incidence and prevalence of 7.7 new cases per 100,000 inhabitants per years and 34.4 cases per 100,000 inhabitants per year, respectively. Fewer data are available regarding non-EoE EGIDs, whose prevalence are estimated to range between 2.1 and 17.6 in 100,000 individuals, depending on age, sex, and ethnicity. Diagnosis requires the presence of suggestive symptoms, endoscopic biopsies showing abnormal values of eosinophils infiltrating the gut, and exclusion of secondary causes of eosinophilia. EoE typically presents with dysphagia and episodes of food bolus impactions, while EoG, EoN, and EoC may all present with abdominal pain and diarrhea, with or without other non-specific symptoms. In addition, although different EGIDs are currently classified as different entities, there may be overlap between different diseases in the same patient. Despite EGIDs being relatively novel pathological entities, the research on possible treatments is rapidly growing. In this regard, several randomized controlled trials are currently ongoing to investigate novel molecules, including ad-hoc steroid formulations, immunosuppressants, and mostly monoclonal antibodies that target the specific molecular mediators of EGIDs. This narrative review provides an up-to-date overview of available and investigational drugs for different EGIDs.

Personalized and Precision Medicine in Asthma and Eosinophilic Esophagitis: The Role of T2 Target Therapy

The role of type 2 inflammation has been progressively associated with many diseases, including severe asthma, atopic dermatitis, nasal polyposis, eosinophilic granulomatosis with polyangiitis, and, recently, eosinophilic esophagitis. Despite this, the association between asthma and esophagitis is still poorly known, and this is probably because of the low prevalence of each disease and the even lower association between them. Nonetheless, observations in clinical trials and, subsequently, in real life, have allowed researchers to observe how drugs acting on type 2 inflammation, initially developed and marketed for severe asthma, could be effective also in treating eosinophilic esophagitis. For this reason, clinical trials specifically designed for the use of drugs targeted to type 2 inflammation were also developed for eosinophilic esophagitis. The results of clinical trials are presently promising and envisage the use of biologicals that are also likely to be employed in the field of gastroenterology in the near future. This review focuses on the use of biologicals for type 2 inflammation in cases of combined severe asthma and eosinophilic esophagitis.

Recent insights into comorbidities in atopic dermatitis

INTRODUCTION

The relationship between atopic dermatitis and atopic diseases such as food allergies, asthma, and allergic rhinitis in terms of co-occurrence, underlying mechanisms, and therapy is well documented. There is increasing evidence that atopic dermatitis is associated with non-atopic comorbidities such as cardiac, autoimmune, and neuropsychological comorbidities, as well as cutaneous and extracutaneous infections, establishing atopic dermatitis as a systemic disease.

AREAS COVERED

The authors reviewed evidence on atopic and non-atopic comorbidities of atopic dermatitis. A literature search was conducted in PubMed for peer-reviewed articles published until October 2022.

EXPERT OPINION

Atopic and non-atopic diseases coexist with atopic dermatitis more often than would be expected by chance. The effect of biologics and small molecules on atopic and non-atopic comorbidities may contribute to a better understanding of the relationship between atopic dermatitis and its comorbidities. Their relationship needs to be explored further to dismantle the underlying mechanism and move toward an atopic dermatitis endotype-based therapeutic approach.

Multicentric reticulohistiocytosis with eosinophilic gastroenteritis: An unusual relationship

Multicentric reticulohistiocytosis (MRH) is a rare disease with poorly defined therapeutic strategies. Here, we report the case of a patient with eosinophilic gastroenteritis who developed MRH after 5 years. The patient presented with disabling and rapidly progressive polyarthralgia, eosinophilic gastroenteritis, and resistance to first-line therapies. However, there was a marked improvement in the arthritis symptoms following treatment with tofacitinib. This presentation provides a useful perspective for the therapeutic management of complex scenarios involving MRH.

Current and emerging therapies for eosinophilic esophagitis

Background: Eosinophilic esophagitis (EoE) is a Type-2 chronic inflammatory food antigen-driven disease of the esophagus, characterized by eosinophilic predominant inflammation and a constellation of symptoms. The incidence and prevalence of EoE has increased over the past 2 decades. There is an unmet need for approved less burdensome treatment options. Objective: To describe the underlying pathophysiology and diagnosis of EoE and discuss the currently available treatment options. We also aim to review the new and emerging therapies for EoE. Methods: A search of a medical literature data base was performed for articles that discuss treatment for EoE. Results: A comparison of current therapies showed that dietary elimination, swallowed topical corticosteroids, and proton-pump inhibitor therapy are all effective for different populations. Emerging therapies that were reviewed include new topical corticosteroids and biologics directed against Type 2 inflammation. Conclusion: EoE is a chronic inflammatory disorder that can be debilitating, with long-term sequelae. There are no current approved therapies in the United States. Numerous new treatments are on the horizon. Increasing amounts of data are helping to tailor treatment for each patient. Ultimately, shared decision-making is the best approach to guide treatment choices with patients to manage the ever-increasing burden of this disease.

Evidence-based treatments for eosinophilic esophagitis: insights for the clinician

Eosinophilic esophagitis (EoE) is a chronic inflammatory disorder characterized by symptoms of esophageal dysfunction and eosinophil-predominant inflammation. Left untreated, EoE progresses to fibrous remodeling and stricture formation that impairs quality of life. Therefore, EoE requires either repeated treatments or maintenance therapy. Current guidelines recommend swallowed topical corticosteroids (STCs), proton-pump inhibitors (PPIs), or dietary intervention as initial options to induce and maintain long-term disease remission. Impractical exclusive elemental diets and suboptimal allergy testing-directed food avoidance paved the way for empirical elimination diets. These are moderately effective and highly reproducible in inducing EoE remission and allow for identification of specific food triggers. Step-up strategies, including two- and four-food rather than six-food elimination diets, should be considered as initial approaches for dietary treatment in patients of all ages, as they reduce the need for endoscopic procedures, shorten diagnostic processing time, and avoid unnecessary restrictions. Formulations of STC originally designed for asthma therapy are suboptimal for EoE treatment, with new effervescent orodispersible tablets and viscose formulations designed to coat the esophageal mucosa providing increased effectiveness at reduced doses. The anti-inflammatory effects of PPI in EoE are independent from gastric acid secretion inhibition; despite evidence from observational research, PPIs are the most commonly prescribed first-line therapy for EoE due to their accessibility, low cost, and safety profile. Double doses of PPI only induce remission in half of EoE patients, irrespective of the drug used or patients' age. Inflammatory rather than stricturing EoE phenotype and treatment duration up to 12 weeks increase chances of achieving EoE remission. Most responders effectively maintain long-term remission with standard PPI doses. Finally, endoscopic dilation should be considered in patients with reduced esophageal caliber or persistent dysphagia despite histological remission. This article provides a state-of-the-art review and updated discussion of current therapies and newly developed options for EoE.

Type 2 Inflammation in Eosinophilic Esophagitis: From Pathophysiology to Therapeutic Targets

Eosinophilic esophagitis (EoE) is a chronic immune-mediated disease of the esophagus characterized clinically by symptoms related to esophageal dysfunction and histologically by eosinophil-predominant inflammation, whose incidence is rising. It significantly affects patients’ quality of life and, if left untreated, results in fibrotic complications. Although broad consensus has been achieved on first-line therapy, a subset of patients remains non-responder to standard therapy. The pathogenesis of EoE is multifactorial and results from the complex, still mostly undefined, interaction between genetics and intrinsic factors, environment, and antigenic stimuli. A deep understanding of the pathophysiology of this disease is pivotal for the development of new therapies. This review provides a comprehensive description of the pathophysiology of EoE, starting from major pathogenic mechanisms (genetics, type 2 inflammation, epithelial barrier dysfunction, gastroesophageal reflux, allergens, infections and microbiota) and subsequently focusing on the single protagonists of type 2 inflammation (involved cells, cytokines, soluble effectors, surface proteins and transcription factors) that could represent present and future therapeutic targets, while summarizing previous therapeutic approaches in literature.

Pathophysiology of Non-IgE-Mediated Food Allergy

Non-IgE-mediated food allergies are a group of disorders characterized by subacute or chronic inflammatory processes in the gut. Unlike IgE mediated food allergies that may result in multi-organ system anaphylaxis, the non-IgE mediated food allergies primarily affect the gastrointestinal tract. This review outlines the clinical manifestations, epidemiology, pathophysiology, and management of non-IgE-mediated food allergies. An updated literature search of selected non-IgE-mediated food allergies was conducted for this review using PubMed database to the current year (2021). Reviewed disorders include food protein-induced enterocolitis syndrome (FPIES), food-protein enteropathy (FPE), food protein-induced allergic proctocolitis (FPIAP), and eosinophilic gastrointestinal disorders (EGIDs) such as eosinophilic esophagitis (EoE). While extensive gains have been made in understanding FPIES, FPIAP, FPE, and EoE, more information is needed on the pathophysiology of these food allergies. Similarities among them include involvement of innate immunity, T-lymphocyte processes, alteration of the intestinal lumen at the cellular level with the appearance of inflammatory cells and associated histologic changes, and specific cytokine profiles suggesting food-specific, T-cell, and immune-mediated responses. While FPIES and FPIAP typically resolve in early childhood, EGIDs typically do not. Emerging new therapies for EoE offer promise of additional treatment options. Further studies identifying the immunopathogenesis, associated biomarkers, and mechanisms of tolerance are needed to inform prevention, diagnosis and management.

Role of Eosinophils in Intestinal Inflammation and Fibrosis in Inflammatory Bowel Disease: An Overlooked Villain?

Eosinophils are leukocytes which reside in the gastrointestinal tract under homeostatic conditions, except for the esophagus which is normally devoid of eosinophils. Research on eosinophils has primarily focused on anti-helminth responses and type 2 immune disorders. In contrast, the search for a role of eosinophils in chronic intestinal inflammation and fibrosis has been limited. With a shift in research focus from adaptive to innate immunity and the fact that the eosinophilic granules are filled with inflammatory mediators, eosinophils are becoming a point of interest in inflammatory bowel diseases. In the current review we summarize eosinophil characteristics and recruitment as well as the current knowledge on presence, inflammatory and pro-fibrotic functions of eosinophils in inflammatory bowel disease and other chronic inflammatory conditions, and we identify research gaps which should be covered in the future.

Emerging Therapies for Eosinophilic Gastrointestinal Diseases

Besides eosinophilic esophagitis, other eosinophilic gastrointestinal diseases (EGIDs), such as eosinophilic gastritis, eosinophilic gastroenteritis, and eosinophilic colitis, are increasingly diagnosed over the last decade. Whereas diagnosis and therapy of eosinophilic esophagitis have been standardized, the diagnosis and therapy of other EGIDs are areas of active research. Motivated by the increasing prevalence of these conditions, concerted efforts of different stakeholders have led to the evaluation of targeted biologic therapies for EGID management over the last couple of years, and several promising molecules are currently in the pipeline. This review article provides an overview of targeted biologic therapies for use in EGIDs.

Targeted Therapies for Eosinophilic Gastrointestinal Disorders

The growing recognition of eosinophilic gastrointestinal disorders has revealed the limitations of current treatment (mainly based on dietary modification and corticosteroids), and include refractoriness, high recurrence rates, and the need for long-term therapy. Research efforts, mainly in eosinophilic esophagitis (EoE), have unveiled essential pathophysiological mechanisms leading to these disorders, which bear some similarities to those of atopic manifestations and are shared by eosinophilic gastroenteritis (EGE) and eosinophilic colitis (EC). Novel targeted therapies, some imported from bronchial asthma and atopic dermatitis, are currently being assessed in EoE. The most promising are monoclonal antibodies, including those targeting interleukin (IL)-13 (cendakimab) and IL-4 (dupilumab), with phase 3 trials currently ongoing. The potential of anti-integrin therapy (vedolizumab) and Siglec-8 blockers (antolimab) in EGE are also promising. Non-biological therapies for eosinophilic gut disorders, which include preventing the activation of Janus kinase (JAK)-signal transducer and activator of transcription (STAT) and chemoattractant receptor expressed on T helper 2 cells (CRTH2) signaling pathways, and other potential targets that deserve investigation in eosinophilic gut disorders, are reviewed.