Biological therapies for eosinophilic gastrointestinal diseases

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.

Benralizumab for eosinophilic gastritis: a single-site, randomised, double-blind, placebo-controlled, phase 2 trial

BACKGROUND

In eosinophilic gastrointestinal diseases, the role of eosinophils in disease pathogenesis and the effect of eosinophil depletion on patient outcomes are unclear. Benralizumab, an eosinophil-depleting monoclonal antibody that targets the interleukin-5 receptor α, might eliminate gastric tissue eosinophils and improve outcomes in eosinophilic gastritis. We aimed to assess the efficacy and safety of benralizumab in patients with eosinophilic gastritis.

METHODS

We conducted a single-site, randomised, double-blind, placebo-controlled, phase 2 trial at Cincinnati Children's Hospital Medical Center (Cincinnati, OH, USA). Individuals aged 12-60 years with symptomatic, histologically active eosinophilic gastritis (peak gastric eosinophil count ≥30 eosinophils per high-power field [eos/hpf] in at least five hpfs) and blood eosinophilia (>500 eosinophils per μL [eos/μL]) were randomly assigned (1:1, block size of four) to benralizumab 30 mg or placebo, stratified by the use of glucocorticoids for gastric disease. Investigators, study staff, and study participants were masked to treatment assignment; statisticians were unmasked when analysing data. Treatments were administered subcutaneously once every 4 weeks for a 12-week double-blind period (three total injections). The primary endpoint was the proportion of patients who achieved histological remission (peak gastric eosinophil count <30 eos/hpf) at week 12. Key secondary endpoints were the changes from baseline to week 12 in peak gastric eosinophil count, blood eosinophil count, eosinophilic gastritis histology (total, inflammatory, and structural feature scores), Eosinophilic Gastritis Endoscopic Reference System (EG-REFS) score, and patient-reported outcome symptom measures (Severity of Dyspepsia Assessment [SODA] and Patient-Reported Outcome Measurement Information System [PROMIS] short-form questionnaire). After the 12-week double-blind period, patients were eligible for entry into two open-label extension (OLE) periods up to week 88, in which all patients received benralizumab. Efficacy was analysed in the intention-to-treat (ITT) population and safety was assessed in all patients who received at least one dose of study drug. The trial was registered on ClinicalTrials.gov, NCT03473977, and is completed.

FINDINGS

Between April 23, 2018, and Jan 13, 2020, 34 patients were screened, and 26 were subsequently randomly assigned to benralizumab (n=13) or placebo (n=13) and included in the ITT and safety populations (mean age 19·5 years [SD 7·3]; 19 [73%] male patients and seven [27%] female patients). At week 12, ten (77% [95% CI 50 to 92]) of 13 patients who received benralizumab and one (8% [1 to 33]) of 13 who received placebo achieved histological remission (difference 69 percentage points [95% CI 32 to 85]; p=0·0010). Changes from baseline to week 12 were significantly greater in the benralizumab group versus the placebo group for peak gastric eosinophil counts (mean -137 eos/hpf [95% CI -186 to -88] vs -38 eos/hpf [-94 to 18]; p=0·0080), eosinophilic gastritis histology total score (mean -0·31 [-0·42 to -0·20] vs -0·02 [-0·16 to 0·12]; p=0·0016), histology inflammatory score (mean -0·46 [-0·60 to -0·31] vs -0·04 [-0·22 to 0·13]; p=0·0006), and blood eosinophil counts (median -1060 eos/μL [IQR -1740 to -830] vs -160 eos/μL [-710 to 120]; p=0·0044). Changes were not significantly different between the groups for eosinophilic gastritis histology structural score (mean -0·07 [95% CI -0·19 to 0·05] vs 0·03 [-0·09 to 0·15]; p=0·23), EG-REFS score (mean -1·0 [-2·3 to 0·3] vs -0·5 [-2·0 to 1·0]; p=0·62), or in patient-reported outcomes (SODA and PROMIS). During the double-blind period, treatment-emergent adverse events occurred in 11 (85%) of 13 patients in the benralizumab group and six (46%) of 13 in the placebo group; the most common treatment-emergent adverse events were headache (six [46%] vs two [15%] patients), nausea (three [23%] vs two [15%]), and vomiting (two [15%] vs three [23%]). There were no treatment-related deaths. Two patients had serious adverse events (dizziness and rhabdomyolysis in one patient; aspiration in one patient) during the OLE periods, which were considered unrelated to study treatment.

INTERPRETATION

Benralizumab treatment induced histological remission, as defined by absence of tissue eosinophilia, in most patients with eosinophilic gastritis. However, the persistence of histological, endoscopic, and other features of the disease suggest a co-existing, eosinophil-independent pathogenic mechanism and the need for broader targeting of type 2 immunity.

FUNDING

AstraZeneca and the Division of Intramural Research (National Institute of Allergy and Infectious Diseases, US National Institutes of Health).

Associations of Gastrointestinal Tract Tumor Necrosis Factor Receptor-Associated Factor 6 Expression with Clinical Features and Prognosis of Eosinophilic Gastroenteritis

BACKGROUND

Few studies have been conducted to explore the expression of tumor necrosis factor receptor-associated factor 6 in eosinophilic gastroenteritis patients. Therefore, the expression profile of tumor necrosis factor receptor-associated factor 6 in the gastrointestinal tract of eosinophilic gastroenteritis patients and its associations with clinical features were explored in this study.

METHODS

Thirty-four eosinophilic gastroenteritis patients who presented in Ruijin Hospital from December 2012 to May 2019 and had accepted gastrointestinal endoscopic examinations were recruited. Medical records and endoscopic biopsies were collected, and the prognosis was followed up by telephone. Healthy persons were selected as the control group. Hematoxylin and eosin and immunohistochemical staining were performed in both eosinophilic gastroenteritis patients and healthy persons. The final results were analyzed by skilled pathologists, and mean optical density values of tumor necrosis factor receptor-associated factor 6 were calculated by Image J software. Final results were analyzed by Statistical Package for the Social Sciences software 22.0.

RESULTS

Thirty-four patients (mean age: 25.56 ± 21.14 years, 61.76% males) were recruited for this study. There was no significant difference in tumor necrosis factor receptor-associated factor 6 mean optical density values of gastric tissues in eosinophilic gastroenteritis patients and healthy people (0.22 ± 0.16 vs. 0.14 ± 0.05, P > .05). Eosinophilic gastroenteritis patients had a significantly lower level of intestinal tumor necrosis factor receptor-associated factor 6 mean optical density values than that of healthy people (0.16 ± 0.05 vs. 0.23 ± 0.06, P < .05). Intestinal tumor necrosis factor receptor-associated factor 6 mean optical density values negatively linearly correlated with serum interleukin-10 level (r = -0.618, P = .043 < .05). There were no differences between eosinophilic gastroenteritis patients with or without relapse regarding the expression level of intestinal tumor necrosis factor receptor-associated factor 6 (P = .227 > .05).

CONCLUSION

Patients with eosinophilic gastroenteritis might have a deficiency of intestinal tumor necrosis factor receptor-associated factor 6 compared to healthy controls.

EoE behaves as a unique Th2 disease: a narrative review

Background and Objective

To highlight and interpret two significant differences between eosinophilic esophagitis (EoE), a type 2 helper cell (Th2) disease, and three other representative Th2 diseases. EoE, asthma, atopic dermatitis (AD), chronic rhinosinusitis (CRS) and other Th2 diseases employ epithelial alarmins to recognize triggers, share a prototypical inflammatory cascade, and respond to glucocorticoids. However, EoE also has several distinguishing characteristics which may be explained by a distinct pathophysiologic mechanism.

Methods

The following report consist of four related narrative reviews which combine comprehensive PubMed and Google searches. Two reviews were performed to identify and contrast all eligible studies describing serologic markers in EoE compared to asthma, AD, and CRS. Two additional reviews then compare the responses to parenteral biological therapies in EoE and in the same representative Th2 diseases.

Key Content and Findings

Comprehensive literature searches definitively differentiate the absence of serologic markers in EoE compared to their identification in the other representative Th2 diseases. Similarly, a summary of therapeutic trials demonstrates that while EoE is unable to clinically respond to a variety of parenteral biological therapies, asthma, AD and CRS are very effectively treated with this same approach. A novel pathophysiology for EoE is proposed, and the emerging literature that support its existence is summarized.

Conclusions

The fundamental properties described in this narrative regarding serologic signaling and response to parenteral therapy in EoE could be explained if EoE employs a unique application of the Th2 pathway. One potential mechanism consistent with these observations is that EoE employs exclusively esophageal mucosal constituents to initiate and generate the prototypical Th2 cascade and the fibrostenotic changes that follow.

Role of mast cells in eosinophilic esophagitis

PURPOSE OF REVIEW

This review will present what is known from recent research on the involvement of mast cells in eosinophilic esophagitis and identify questions requiring further investigation.

RECENT FINDINGS

In the adults and children with eosinophilic esophagitis, there is increasing evidence that mastocytosis can persist, despite resolution of eosinophilia and is associated with persistent mucosal abnormalities and symptoms. Despite, treatment mast cells have an activated transcriptome. Mast cells likely contribute to epithelial barrier dysfunction, smooth muscle hypertrophy and contraction, and subepithelial fibrosis. It remains unclear whether targeting MCs alone has therapeutic efficacy to improve tissue damage.

SUMMARY

Mast cells appear to play a key role in eosinophilic esophagitis and serve as a biomarker of mucosal healing in conjunction with eosinophils. Excessive mast cell activation likely contributes to tissue damage in eosinophilic esophagitis and need to be considered as a target of therapy along with eosinophils.

Eosinophils and eosinophilic immune dysfunction in health and disease

The functions ascribed to eosinophils have classically been limited to host defence against certain parasitic infections and potentially deleterious effects in the setting of specific diseases that are associated with elevated eosinophil counts in blood and/or tissue. The ability to induce eosinophil depletion either experimentally in animal models or through targeted therapies in humans has extended our understanding of the roles played by eosinophils in health and homeostasis as well as in disease pathogenesis. When associated with human disease aetiology, the eosinophil takes on a pathogenic rather than a protective role. This maladaptive response, called "eosinophilic immune dysfunction" herein, appears central to exacerbation pathogenesis and disease control in severe asthma and may be involved in the aetiology of other eosinophil-related conditions ranging from organ-system-limited diseases such as phenotypic subsets of chronic obstructive pulmonary disease and chronic rhinosinusitis with nasal polyposis to more broadly systemic diseases such as eosinophilic granulomatosis with polyangiitis and hypereosinophilic syndrome. In this review, we describe the evidence supporting eosinophilic functions related to health and homeostasis and explore the contribution of eosinophilic immune dysfunction to human disease.

Proton Pump Inhibitor Therapy for Eosinophilic Esophagitis: History, Mechanisms, Efficacy, and Future Directions

Over the past decade, the role of proton pump inhibitor (PPI) medication has evolved from a diagnostic tool for Eosinophilic Esophagitis (EoE), by excluding patients with PPI responsive esophageal eosinophilia (PPI-REE), to a therapy for EoE. This transition resulted from the Updated International Consensus Diagnostic Criteria for Eosinophilic Esophagitis: Proceedings of the Appraisal of Guidelines for Research and Evaluation II (AGREE) Conference to support PPI therapy for EoE in children and adults. Additional recent advances have suggested a role for genetic variations that might impact response to PPI therapy for EoE. This review article will explore a brief background of EoE, the evolution of PPI therapy for EoE and its proposed mechanisms, efficacy and safety in children and adults, and considerations for future PPI precision medicine in patients with EoE.

Continued Basal Zone Expansion After Resolution of Eosinophilia in a Child With Eosinophilic Esophagitis on Benralizumab

ABSTRACT

A 20-year-old woman presented with dysphagia at 8 years of age. She underwent esophagogastroduodenoscopy with biopsies (EGD), which was diagnostic of eosinophilic esophagitis. Diet elimination resulted in improvement in symptoms, reduction in eosinophilia, and resolution of basal zone hyperplasia (BZH) on repeat EGD; however, food reintroduction resulted in recurrence of eosinophilia. Subsequently, her pulmonologist started benralizumab, a monoclonal antibody against the interleukin-5 receptor (IL5Rα) on eosinophils, for her asthma. Seven months after starting benralizumab, she underwent EGD for persistent dysphagia, which was notable for resolution of esophageal eosinophilia but demonstrated marked BZH in association with high numbers of CD3+ T cells and tryptase+ mast cells. She transitioned to dupilumab and had resolution of dysphagia. EGD was performed 10 months after starting dupilumab and demonstrated resolution of BZH and mast cell inflammation with significant reduction in T cells. Review of other patients at our center treated with biologics, most commonly dupliumab, reveals varying degrees of BZH in association with mostly CD3+ lymphocyte inflammation. Mast cells and T cells appear to be capable of coordinating mucosal inflammation and symptoms of EoE independent of eosinophilia in a subset of patients.

Eosinophilic esophagitis an update in children

Eosinophilic esophagitis (EoE) is an emerging antigen-mediated, inflammatory disease of unknown etiology. EoE affects about 1/2,000 patients in the United States (US), with a higher prevalence rate in adults (43.4/100,000) than in children (29.5/100,000), prevailing in Caucasians and male sex. EoE is a multifactorial disease typically characterized by type 2 inflammation. Pathogenesis is not entirely understood and is likely non-IgE mediated. Food allergens trigger EoE, stimulating the dysregulated immune cells through an impaired esophageal epithelial barrier. Clinical presentation of EoE depends on age and mainly includes food refusal, vomiting, abdominal or chest pain, dysphagia, and food impaction. Endoscopy is the gold standard to diagnose EoE. The goal of EoE therapy is to achieve clinical and histological remission to prevent esophageal fibrosis and improve patients' quality of life (QoL). Cornerstones of therapy are PPIs, topical steroids, and elimination diets. Over recent decades, research progress has been made in terms of a greater understanding of the EoE pathogenesis and new therapeutic approaches. However, there are still several unmet needs, such as non-invasive tools and biomarkers for monitoring the disease.

Pediatric eosinophilic esophagitis: a review for the clinician

Eosinophilic esophagitis (EoE) is a chronic clinical-pathologic disease characterized by eosinophilic infiltration of the esophageal epithelium with esophageal dysfunction symptoms.EoE can occur at any age and has different clinical manifestations depending on the age onset.To date, esophago-gastroduodenal endoscopy (EGD) with biopsy is the gold-standard for EoE diagnosis.According to the recent consensus guidelines, proton pump inhibitors, corticosteroids and elimination diets could be a first-line therapy option. The aim of the treatment is clinical and histological remission for preventing long-lasting untreatable fibrosis.A multidisciplinary approach (allergist, gastroenterology, dietitian, and pathologist) is recommended for managing patients affected by EoE, given the complexity of its treatment.This review will provide a practical guide to assist pediatricians treating children with EoE.Moreover, it highlights the unmet needs in diagnosis and treatment that require urgent attention from the scientific community in the aim of improving the management of patients with EoE.

Periostin in Allergy and Inflammation

Matricellular proteins are involved in the crosstalk between cells and their environment and thus play an important role in allergic and inflammatory reactions. Periostin, a matricellular protein, has several documented and multi-faceted roles in health and disease. It is differentially expressed, usually upregulated, in allergic conditions, a variety of inflammatory diseases as well as in cancer and contributes to the development and progression of these diseases. Periostin has also been shown to influence tissue remodelling, fibrosis, regeneration and repair. In allergic reactions periostin is involved in type 2 immunity and can be induced by IL-4 and IL-13 in bronchial cells. A variety of different allergic diseases, among them bronchial asthma and atopic dermatitis (AD), have been shown to be connected to periostin expression. Periostin is commonly expressed in fibroblasts and acts on epithelial cells as well as fibroblasts involving integrin and NF-κB signalling. Also direct signalling between periostin and immune cells has been reported. The deposition of periostin in inflamed, often fibrotic, tissues is further fuelling the inflammatory process. There is increasing evidence that periostin is also expressed by epithelial cells in several of the above-mentioned conditions as well as in cancer. Augmented periostin expression has also been associated with chronic inflammation such as in inflammatory bowel disease (IBD). Periostin can be expressed in a variety of different isoforms, whose functions have not been elucidated yet. This review will discuss potential functions of periostin and its different isoforms in allergy and inflammation.

Update on the Role of Allergy in Pediatric Functional Abdominal Pain Disorders: A Clinical Perspective

Both functional abdominal pain disorders (FAPDs) and food allergies are relatively common in children and adolescents, and most studies report an association between FAPDs and allergic conditions. FAPDs share pathophysiologic processes with allergies, including both immune and psychological processes interacting with the microbiome. No conclusive data are implicating IgE-mediated reactions to foods in FAPDs; however, there may be patients who have IgE reactions localized to the gastrointestinal mucosa without systemic symptoms that are not identified by common tests. In FAPDs, the data appears stronger for aeroallergens than for foods. It also remains possible that food antigens initiate an IgG reaction that promotes mast cell activation. If a food allergen is identified, the management involves eliminating the specific food from the diet. In the absence of systemic allergic symptoms or oral allergy syndrome, it appears unlikely that allergic triggers for FAPDs can be reliably identified by standard testing. Medications used to blunt allergic reactions or symptomatically treat allergic reactions may be useful in FAPDs. The purpose of the current manuscript is to review the current literature regarding the role of allergy in FAPDs from a clinical perspective, including how allergy may fit in the current model of FAPDs.

Role of Short Chain Fatty Acids and Apolipoproteins in the Regulation of Eosinophilia-Associated Diseases

Eosinophils are key components of our host defense and potent effectors in allergic and inflammatory diseases. Once recruited to the inflammatory site, eosinophils release their cytotoxic granule proteins as well as cytokines and lipid mediators, contributing to parasite clearance but also to exacerbation of inflammation and tissue damage. However, eosinophils have recently been shown to play an important homeostatic role in different tissues under steady state. Despite the tremendous progress in the treatment of eosinophilic disorders with the implementation of biologics, there is an unmet need for novel therapies that specifically target the cytotoxic effector functions of eosinophils without completely depleting this multifunctional immune cell type. Recent studies have uncovered several endogenous molecules that decrease eosinophil migration and activation. These include short chain fatty acids (SCFAs) such as butyrate, which are produced in large quantities in the gastrointestinal tract by commensal bacteria and enter the systemic circulation. In addition, high-density lipoprotein-associated anti-inflammatory apolipoproteins have recently been shown to attenuate eosinophil migration and activation. Here, we focus on the anti-pathogenic properties of SCFAs and apolipoproteins on eosinophil effector function and provide insights into the potential use of SCFAs and apolipoproteins (and their mimetics) as effective agents to combat eosinophilic inflammation.

Long-term Efficacy and Tolerability of RPC4046 in an Open-Label Extension Trial of Patients With Eosinophilic Esophagitis

BACKGROUND & AIMS

The short-term efficacy of RPC4046, a monoclonal antibody against interleukin-13, has been shown in patients with eosinophilic esophagitis (EoE). We investigated the long-term efficacy and safety of RPC4046 in an open-label, long-term extension (LTE) study in adults with EoE.

METHODS

We analyzed data from 66 patients who completed the 16-week, double-blind, induction portion of a phase 2 study of RPC4046 (180 mg or 360 mg/wk) vs placebo and then completed a 52-week LTE, receiving open-label RPC4046 360 mg/wk. The study was conducted at 28 centers in 3 countries; patients were enrolled between September 2014 and January 2017. Outcomes were stratified by double-blind dose group and included esophageal eosinophil counts, EoE endoscopic reference score, EoE histologic scoring system score, symptom-based EoE activity index score, and safety.

RESULTS

By week 12 of the LTE, esophageal eosinophil mean and peak counts, total EoE endoscopic reference scores, and EoE histologic scoring system grade and stage scores did not differ considerably between patients who originally received placebo vs RPC4046. Most patients maintained responses through week 52. Symptom remission (symptom-based EoE activity index score, ≤20) increased from 14% at LTE entry to 67% at LTE week 52 in placebo‒RPC4046 patients and from 30% to 54% in RPC4046‒RPC4046 (either dose) patients. Of the 28 patients who did not have a histologic response to RPC4046 during the double-blind induction phase, 10 patients (36%) achieved response during the LTE. The most common adverse events were upper respiratory tract infection (21%) and nasopharyngitis (14%).

CONCLUSIONS

One year of treatment with RPC4046 is generally well tolerated and results in continued improvement and/or maintenance of endoscopic, histologic, and clinical measures of EoE disease activity relative to baseline.

TRIAL REGISTRATION

NCT02098473.

Conserved IFN Signature between Adult and Pediatric Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) is an allergic inflammatory disease of the esophagus that occurs in both children and adults. Previous studies of affected tissue from pediatric cohorts have identified prominent signatures of eosinophilia and type 2 inflammation. However, the details of the immune response in adults with EoE are still being elucidated. To determine whether EoE in adults shares inflammatory profiles with those observed in children, we performed RNA sequencing of paired human esophageal biopsies and blood samples from adults with EoE or gastroesophageal reflux disease. Unbiased analysis of differentially expressed genes in tissue revealed a strong IFN signature that was significantly enriched in EoE patients as compared with patients with gastroesophageal reflux disease. Both type I and type II IFN-responsive genes were upregulated in adult biopsies, but not in blood. A similar increase in expression of IFN gene sets was observed in pediatric EoE biopsies as compared with non-EoE samples, and in public pediatric and adult RNA-sequencing data. Finally, we found that human peripheral CD4⁺ T cells from children with EoE produce IFN-γ upon activation with EoE-causal allergens. Together, this work identifies a conserved IFN signature in pediatric and adult EoE, highlighting a role for non-type 2 inflammatory networks in the disease process in humans.

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.

Food allergy and eosinophilic gastrointestinal disorders

Eosinophilic esophagitis (EoE) is a non-immunoglobulin E mediated disorder that has been seen with increasing frequency over the past 25 years. Although the presentation varies per age group from vomiting and refusal to eat in infants and toddlers to abdominal pain and dysphagia in school-aged children, and food impaction and indigestion in adolescents and adults. Treatment options include proton-pump inhibitors, dietary avoidance, swallowed steroids, or a combination of these. Newer therapies with biologics show promise in early studies. Cow's milk is the most common food trigger of EoE across all age groups, followed by wheat and eggs. Different dietary avoidance strategies have been used, and help from a knowledgeable nutritionist is often key to success. Patients with EoE commonly have other baseline atopic disease. Clinicians who take care of patients who are atopic, therefore, should have a higher index of suspicion for EoE in patients with dysphagia. The goals of treatment are both a decrease in symptoms and normalization of esophageal histology. Eosinophilic gastrointestinal diseases are less common and less likely to respond to dietary therapies and/or avoidance. Pathogenesis seems to be different and may be more autoimmune mediated. Trialing dietary restrictions is certainly an option in this cohort of patients. For persistent symptoms and abnormalities, systemic medications have been used, although biologics may be used in the future. Additional studies are needed to determine which patients will respond to which therapies.

The Hidden Burden of Severe Asthma: From Patient Perspective to New Opportunities for Clinicians

Severe asthma is an important topic in respiratory diseases, due to its high impact on morbidity and mortality as well as on health-care resources. The many challenges that still exist in the management of the most difficult-to-treat forms of the disease, and the acknowledgement of the existence of unexplored areas in the pathophysiological mechanisms and the therapeutic targets represent an opportunity to gather experts in the field with the immediate goals to summarize current understanding about the natural history of severe asthma and to identify gaps in knowledge and research opportunities, with the aim to contribute to improved medical care and health outcomes. This article is a consensus document from the “International Course on Severe Asthma” that took place in Palermo, Italy, on May 10–11, 2019. Emerging topics in severe asthma were addressed and discussed among experts, with special focus on patient’s needs and research opportunities, with the aim to highlight the unanswered questions in the diagnostic process and therapeutic approach.

Clinical and Psychological Impact of COVID-19 Infection in Adult Patients with Eosinophilic Gastrointestinal Disorders during the SARS-CoV-2 Outbreak

Eosinophilic gastrointestinal diseases (EGIDs) are chronic gastrointestinal conditions requiring corticosteroid and immunosuppressive therapy for disease control. Patients with EGIDs usually report impaired quality of life. We aimed to report the clinical and psychological impact of COVID-19 infection in EGID patients. In this prospective web-based study we invited all consecutive EGID patients attending the University Hospital of Salerno (Campania) and Padua (Veneto) to fill an ad hoc COVID-19 survey. Moreover, a telemedicine service for direct consultation was organized. Data regarding the occurrence and perception of COVID-19 infection as well as clinical information were recorded. The study population included 102 EGID patients (mean age 36.6 years, 34 females), of whom 89 had eosinophilic esophagitis, nine had gastroenteritis, and four had colitis. No patient was diagnosed with COVID-19 or had recurrence of his/her primary disease. All of them were adherent to therapy and preventive measures adoption. Most patients were worried because of COVID-19 and social preventing measures but did not consider themselves at major risk or susceptible to COVID-19 or other infections due to their chronic condition or therapy. Female gender and low education level were associated to a higher psychological perception of COVID-19 compared to lockdown status or other demographic and clinical factors (p < 0.05). Overall, COVID-19 had a limited clinical impact on patients with EGIDs. The degree of education and sex, but not the fact of living in a lockdown area, influenced the perception of SARS-CoV-2 infection.

Clinical and Psychological Impact of COVID-19 Infection in Adult Patients with Eosinophilic Gastrointestinal Disorders during the SARS-CoV-2 Outbreak

Eosinophilic gastrointestinal diseases (EGIDs) are chronic gastrointestinal conditions requiring corticosteroid and immunosuppressive therapy for disease control. Patients with EGIDs usually report impaired quality of life. We aimed to report the clinical and psychological impact of COVID-19 infection in EGID patients. In this prospective web-based study we invited all consecutive EGID patients attending the University Hospital of Salerno (Campania) and Padua (Veneto) to fill an ad hoc COVID-19 survey. Moreover, a telemedicine service for direct consultation was organized. Data regarding the occurrence and perception of COVID-19 infection as well as clinical information were recorded. The study population included 102 EGID patients (mean age 36.6 years, 34 females), of whom 89 had eosinophilic esophagitis, nine had gastroenteritis, and four had colitis. No patient was diagnosed with COVID-19 or had recurrence of his/her primary disease. All of them were adherent to therapy and preventive measures adoption. Most patients were worried because of COVID-19 and social preventing measures but did not consider themselves at major risk or susceptible to COVID-19 or other infections due to their chronic condition or therapy. Female gender and low education level were associated to a higher psychological perception of COVID-19 compared to lockdown status or other demographic and clinical factors (p < 0.05). Overall, COVID-19 had a limited clinical impact on patients with EGIDs. The degree of education and sex, but not the fact of living in a lockdown area, influenced the perception of SARS-CoV-2 infection.

Strategy for Food Reintroduction Following Empiric Elimination and Elemental Dietary Therapy in the Treatment of Eosinophilic Gastrointestinal Disorders

PURPOSE OF REVIEW

This review presents the available data regarding efficacy of nutritional therapy, highlighting clinical decision points and a strategy for reintroduction of foods following an elemental diet for treatment of eosinophilic gastrointestinal disorders.

RECENT FINDINGS

Elemental and empiric elimination diets are highly effective treatments for eosinophilic gastrointestinal diseases. Standardization in the reintroduction phase, after utilizing the diet for disease remission, is lacking. Clinicians are confronted with multiple challenges regarding the best practice for food reintroduction and identification of potential dietary triggers including order of foods being challenged and duration between endoscopic procedures. Individualization is required for preference and adherence to optimize quality of life and treatment success for this burdensome and life altering immune driven gastrointestinal disorder. Age specific concerns for children, teenagers, and adults should be assessed using a patient centric approach.

Approaches and Challenges to Management of Pediatric and Adult Patients With Eosinophilic Esophagitis

Treatment of eosinophilic esophagitis has progressed from elemental formula for children and esophageal dilation for adults to selective exclusion of food triggers and swallowed topical corticosteroids. Management guidelines are available from the American Gastroenterological Association and the Joint Task Force on Allergy Immunology Practice Parameters. We cannot, however, evaluate the efficacy of treatments without a definition of response. We propose a treat-to-target approach, based on symptoms and findings from endoscopy and histology. This approach addresses dissociations between outcomes, such as symptom persistence despite normalization of histologic features and symptom resolution after esophageal dilation despite histologic features of active disease. Eosinophilic esophagitis can now be treated with biologic agents that target specific immune pathways, and findings from prospective trials have indicated that less-restrictive, empiric, elimination diets can be effective and reduce the need for repeated endoscopic assessment of disease activity during food reintroduction. We also discuss eosinophilic esophagitis subtypes, factors associated with disease, and advances in management.

Hypersensitivity and adverse reactions to biologics for asthma and allergic diseases

Introduction: The development of new biologic agents has provided definite therapeutic advances but, like with any new medications, safety remains a concern.Areas covered: Using PubMed, we reviewed the literature on the adverse effects (AE) to five biologics approved for asthma and/or allergic diseases: one anti-IgE (omalizumab), three anti-IL5 (mepolizumab, reslizumab, benralizumab), and one anti-IL4 (dupilumab).Expert opinion: Biologic agents approved for asthma and allergic diseases are generally safe. Most common AE are benign and tolerated, though long-term safety is lacking for most of them. A slightly increased risk of anaphylaxis to omalizumab and reslizumab required the inclusion of a black box warning, informing the patient, the need for post-injection observation period, and the provision of epinephrine autoinjectors for self-administration when needed. Hypersensitivity reactions, mainly urticaria and very rarely serum sickness have occurred.

Intersection of biology and therapeutics: type 2 targeted therapeutics for adult asthma

Asthma is a disease of reversible airflow obstruction characterised clinically by wheezing, shortness of breath, and coughing. Increases in airway type 2 cytokine activity, including interleukin-4 (IL-4), IL-5, and IL-13, are now established biological mechanisms in asthma. Inhaled corticosteroids have been the foundation for asthma treatment, in a large part because they decrease airway type 2 inflammation. However, inhaled or systemic corticosteroids are ineffective treatments in many patients with asthma and few treatment options exist for patients with steroid resistant asthma. Although mechanisms for corticosteroid refractory asthma are likely to be numerous, the development of a new class of biologic agents that target airway type 2 inflammation has provided a new model for treating some patients with corticosteroid refractory asthma. The objective of this Therapeutic paper is to summarise the new type 2 therapeutics, with an emphasis on the biological rationale and clinical efficacy of this new class of asthma therapeutics.

Eosinophilic esophagitis and other eosinophilic disorders of the gastrointestinal tract

Eosinophilic disorders of the gastrointestinal tract (EGID) are a group of diseases characterized by an eosinophilic inflammation limited to the GI tract. EoE is by far the most common EGID and is an atopic chronic/relapsing eosinophilic inflammation of the esophagus. It is now recognized as an increasingly common cause of esophageal dysfunction, fibrosis, stricture, and food impaction in children and adults. There are globally accepted guidelines for its treatment that are based on the use of proton pump inhibitors (PPI), corticosteroids, and diet. Many clinical trials have been published on the use of biologics in this disease. Non-EoE-EGID is a rare, more severe disease. No globally accepted guidelines exist for their treatment and diagnosis. Corticosteroids are at the moment the most effective treatment of those diseases.

Contributions of Eosinophils to Human Health and Disease

The human eosinophil has long been thought to favorably influence innate mucosal immunity but at times has also been incriminated in disease pathophysiology. Research into eosinophil biology has uncovered a number of interesting contributions by eosinophils to health and disease. However, it appears that not all eosinophils from all species are created equal. It remains unclear, for example, exactly how having eosinophils benefits the human host when helminth infections in the developed world have become scarce. This review focuses on our current state of knowledge as it relates to human eosinophils. When information is lacking, we discuss lessons learned from mouse studies that may or may not directly apply to human biology and disease. It is an exciting time to be an "eosinophilosopher" because the use of biologic agents that selectively target eosinophils provides an unprecedented opportunity to define the contribution of this cell to eosinophil-associated human diseases.

Oesophageal eosinophilia accompanies food allergy to hen egg white protein in young pigs

BACKGROUND

Esophagitis with eosinophilia, inflammation, and fibrosis represent a chronic condition in humans with food allergies.

OBJECTIVE

In this investigation, we asked whether esophagitis with an eosinophilic component is observed in young pigs rendered allergic to hen egg white protein (HEWP).

METHODS

Food allergy was induced in young pigs using two protocols. In one protocol, sensitized pigs were challenged by gavage with a single dose of HEWP. Clinical signs were monitored for 24 hours, and then, gastrointestinal (GI) tissues were collected for histological examination. The phenotype of circulating, ovalbumin (OVA)-specific T cells also was examined in HEWP challenged animals. In the second protocol, sensitized animals were fed HEWP for 28 days. Animals were then examined by endoscopy and gastrointestinal tissues collected for histological examination.

RESULTS

In pigs challenged by gavage with HEWP, clinical signs were noted in 5/6 pigs including diarrhoea, emesis, and skin rash. Clinical signs were not seen in any control group. Histological analysis revealed significant levels of oesophageal eosinophilic infiltration (P < .05) in 4/6 of these animals, with two also displaying eosinophilic infiltration in the stomach. Eosinophils were not increased in ileum or colon samples. Increased numbers of circulating, OVA-specific CD4+ T cells also were observed in pigs that received HEWP by gavage. In the group of animals fed HEWP, endoscopy revealed clinical signs of esophagitis including oedema, granularity, white spots, and furrowing, while histology revealed oedema, immune cell infiltration, and basal zone hyperplasia.

CONCLUSIONS AND CLINICAL RELEVANCE

Food allergy in the pig can be associated with esophagitis based on histological and endoscopic findings, including eosinophilic infiltration. The young pig may, therefore, be a useful large animal model for the study of eosinophilic esophagitis in humans.

Advances in eosinophilic diseases in 2018

Interest in eosinophil biology and eosinophilic diseases is increasing, as reflected in a doubling of the number of annual articles focused on this topic published in the Journal of Allergy and Clinical Immunology over the past decade. Although the majority of these publications relate to eosinophilic asthma, a growing proportion of them focus on breakthroughs in the diagnosis, treatment, and pathogenesis of other eosinophilic disorders, most notably eosinophilic esophagitis. This review highlights advances in our understanding of eosinophilia and eosinophilic disorders (excluding asthma) published in the Journal in 2018.

A Conceptual Approach to Understanding Treatment Response in Eosinophilic Esophagitis

While the diagnosis and initial treatment of eosinophilic esophagitis are becoming more standardized, there are still major gaps in knowledge related to measuring treatment response. One such question centers on how to measure treatment response and what treatment endpoints should be. This impacts not only patient care and engagement in decision-making, but also the field of drug development. In addition, studies so far have use a myriad of treatment endpoints including over a dozen histologic endpoint criteria. This review will discuss the various stakeholders involved in assessment of treatment endpoints of a complex condition, including patients, practitioners and regulatory agencies, and the care settings in which treatment response is assessed, including routine clinical care, clinical trials, and observational studies. Potential parameters or treatment endpoints such as histology, symptoms, patient-reported outcomes, endoscopy, and biomarkers are discussed along with associated challenges and opportunities. A framework on how to define treatment outcomes is discussed and a conceptual approach treatment response is proposed. This takes into account histology, symptoms, and endoscopic findings and harnesses existing, validated tools. It includes definitions of nonresponse, complete normalization, and a graded response category between these 2 extremes, and also permits flexibility and latitude for modifications as newer knowledge emerges. In addition, ways to position the pediatric population in these endeavors are discussed as are future research directions.

Cost-effective care in eosinophilic esophagitis

OBJECTIVE

To examine costs related to eosinophilic esophagitis (EoE), understand the source of these costs, discuss a possible approach for cost-effective care in EoE, and identify areas for future research in this topic.

DATA SOURCES/STUDY SELECTIONS

Narrative review of the literature from 1977 (first description of EoE) to March 2019, focusing on costs and cost-effectiveness analyses in EoE.

RESULTS

High costs in EoE can be related to diagnostic delays, requirement for upper endoscopy with biopsy for diagnosis and monitoring of disease activity, expensive medications currently used off-label, increased food costs related to dietary elimination treatment, frequent doctor visits with subspecialists, and complications or disease exacerbations. Provision of cost-effective care in EoE is an understudied area, and a patient-centric approach is key. There are multiple areas in which future research can make an impact. These include determining predictors of treatment response, minimally or noninvasive methods to monitor disease activity, and validation of the use of multidisciplinary care.

CONCLUSION

Eosinophilic esophagitis (EoE) is considered to be a rare disease, but the costs of care and burden of disease attributed to EoE are substantial. However, few studies examine either the costs related to EoE or the approach to cost-effective care for the EoE patient. To provide cost-effective care, a patient-centric approach and shared decision-making model are optimal. In addition, a rational strategy for EoE diagnosis and initial treatment, effective maintenance therapy for disease control and ideally to prevent complications, and appropriate long-term monitoring are all required.

Clinical analysis of eosinophilic gastroenteritis

AIM

To analyze the clinical features, diagnosis, and prognosis of eosinophilic gastroenteritis (EG).

METHODS

A retrospective analysis was performed of clinical data of 88 cases with EG at our hospital between June 2013 and August 2018.

RESULTS

Eighty-eight patients were included, with a male to female ratio of 1.2:1. The patients ranged in age from 14 to 73 years, with a mean age 45.1 years. Abdominal pain was the most common symptom, 73.3% of patients had positive allergen screening results, and some patients had negative endoscopic findings. Common endoscopic abnormalities were mainly congestion, erosion, ulcers, polyps and so on, and pathological examination revealed a large number of eosinophils infiltrated in the gastrointestinal tract, with the highest average value detected in the cecum. Treatment with proton pump inhibitors was effective. Glucocorticoid therapy was useful, but the disease could recur.

CONCLUSION

The pathogenesis of EG is still unclear, although it is known that allergens play an important role in it. The clinical manifestations are atypical. An increase of eosinophilic granulocytes in peripheral blood and bone marrow smear can support the diagnosis. Imaging and endoscopic manifestations are not specific. Pathology is the key to diagnosis. Glucocorticoid therapy can obtain good results, but there have been no unified criteria on the specific dosage and course of treatment .

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.

Pediatric eosinophilic esophagitis: updates for the primary care setting

PURPOSE OF REVIEW

Eosinophilic esophagitis (EoE) is a multifactorial, non-IgE-mediated inflammatory disorder of the esophagus and is the most common cause of food impaction in the pediatric population. The purpose of this review is to describe the current recommendations for diagnosis and management of EoE.

RECENT FINDINGS

New data has associated EoE with other allergic disorders of the atopic march as well as several risk factors, which predispose to allergic conditions. A subset of patients with esophageal eosinophilia respond to proton pump inhibitor (PPI) therapy with a partial or complete resolution of esophageal eosinophilia. Therefore, some patients can be treated with PPI alone. If this is unsuccessful, dietary elimination and swallowed steroid therapy are recommended for long-term management. There is a growing appreciation that untreated esophageal inflammation can lead to complications of fibrosis and stricture formation.

SUMMARY

The current review will focus on the diagnosis and management of EoE in the pediatric population. Identification and diagnosis of pediatric patients with EoE is critical to prevent long-term esophageal complications.