Eosinophils and allergic diseases of the gastrointestinal tract

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.

mRNA COVID-19 Vaccine-Associated Subserosal Eosinophilic Gastroenteritis: A Case Report

The World Health Organization declared coronavirus disease 2019 (COVID-19) a global pandemic in March 2020. Several vaccines have been developed to overcome the COVID-19 pandemic, and messenger RNA vaccines, commonly known as mRNA vaccines, were the first COVID-19 vaccines to be authorized in Korea. With the worldwide increase in vaccinations, reports of adverse reactions are increasing. However, to the best of our knowledge, there have been no reports of eosinophilic gastroenteritis (EGE) following mRNA vaccination. Here, we present the first case of EGE in a patient who received a second dose of the mRNA vaccine, BNT162b2 (Pfizer-BioNTech). A previously healthy 34-year-old woman presented to the emergency department with generalized abdominal pain for the preceding 2 weeks. She had received a second dose of the mRNA COVID-19 vaccine 2 weeks prior. Subserosal EGE was diagnosed, oral prednisolone was administered, and she recovered completely.

Follow-Up of a Rare Case of Eosinophilic Gastroenteritis Associated with Persistent Blood Eosinophilia and Multiple Food Allergies

Eosinophilic gastroenteritis (EGE) is a subgroup of the eosinophilic gastro-intestinal disorders (EGIDs), characterized by eosinophilic infiltration and chronic inflammation of the gastrointestinal tract. These are rare diseases with still incompletely elucidated causes and mechanisms, with frequently delayed diagnosis and variable outcome. Despite increased interest in eosinophilic diseases in recent years, fewer data have been published on EGE and no standardized diagnostic and therapeutic approach exists. This paper reports the case of a young male patient diagnosed with EGE in 2017 based on clinical and histopathological criteria and constantly monitored during five years. Besides gastrointestinal eosinophilic infiltration, biopsies also revealed eosinophilic infiltration of the oesophagus, despite no declared characteristic oesophageal symptoms. We found increased specific IgE to multiple foods and progressive blood hypereosinophilia which preceded EGE diagnosis by three years. The EGE management included selective dietary restrictions and pharmacologic therapy based on daily budesonide non-enteric coated tablets, proton pumps inhibitors, antihistamines, cromoglycate, correction of iron, calcium and vitamin D deficiencies. The clinical outcome was good, while blood eosinophilia and endoscopic appearance remained almost unchanged. After one year the patient complained of respiratory symptoms suggesting asthma, needing continuous combined inhaled therapy. The reported case is illustrative for complex presentation, diagnosis and outcome of a rare case of mucosal chronic EGE associated with oesophageal involvement, peripheral eosinophilia, multiple food allergies and asthma.

Eosinophilic Gastritis/Gastroenteritis

PURPOSE OF REVIEW

Eosinophilic gastritis/gastroenteritis (EG/EGE) are rare eosinophilic infiltrative disorders in children and adults that fall under the umbrella term eosinophilic gastrointestinal disorders (EGIDs). EGIDs also include eosinophilic esophagitis (EoE) and eosinophilic colitis. In this article, we present the current literature regarding the clinical presentation, diagnostic criteria, and management of EG/EGE.

RECENT FINDINGS

The underlying complex pathophysiology remains unknown, yet hypersensitivity response is a central component. Unlike EoE, standardized diagnostic criteria are lacking but, promising research employing tissue-based and blood-based methods of diagnosis have been reported. Non-EoE EGIDs are more challenging to treat than EoE. More than a third of patients may achieve spontaneous remission. Still, most will require dietary elimination and/or pharmaceutical interventions, mainly corticosteroids, but also biologics (monoclonal antibodies against IL-4, IL-5, TNFα, integrin α4β7, and IgE), mast-cell stabilizers, leukotriene (LT)-receptor antagonists, and antihistamines. Promising research suggests the role of AK002, an anti-siglec antibody, in clinical and histological improvement. Given the rarity and underdiagnosis of EG/EGE, different natural progression compared to EoE, heterogeneous clinical manifestations, and probable normal endoscopic appearance, it is vital to maintain a high suspicion index in atopic patients, obtain at least 5-6 random biopsies from each site for gastro/duodenal eosinophilic infiltrate with the subsequent exclusion of inflammatory, allergic and infectious differential diagnoses to increase the yield of an accurate diagnosis. Corticosteroids remain the mainstay of treatment, often requiring long-term use. Steroid-sparing agents remain experimental. Goals of therapy move beyond clinical remission but lack evidence to support histological remission.

Clinical Implications of Pediatric Colonic Eosinophilia

OBJECTIVE

Pediatric colonic eosinophilia represents a confounding finding with a wide differential. It is often difficult to determine which children may progress to inflammatory bowel disease (IBD), which have an eosinophilic colitis (EC), and which may have no underlying pathology. There is little guidance for the practitioner on the approach to these patients. To define the clinical presentations of colonic eosinophilia and identify factors which may aid in diagnosis we reviewed patients with colonic eosinophilia and the clinicopathologic factors associated with their diagnoses.

METHODS

An 8-year retrospective chart review of children whose histopathology identified colonic eosinophilia (N = 72) compared to controls with normal biopsies (N = 35).

RESULTS

Patients with colonic eosinophilia had increased eosinophils/high-power field compared to controls (P < 0.001) and had 3 clinical phenotypes. Thirty-six percent had an inflammatory phenotype with elevated erythrocyte sedimentation rate (P < .0001), chronic inflammation on colonic biopsies (P < 0.001), and were diagnosed as having IBD. Thirty-seven percent were diagnosed as having EC, associated with male sex (P < 0.005) and peripheral eosinophilia (P = 0.041). Twenty-one percent had no significant colonic pathology. Forty-three percent of patients had >1 colonoscopy and 68% of these had change from initial diagnoses.

CONCLUSIONS

There are 3 main phenotypes of children with colonic eosinophilia. Signs of chronic systemic inflammation raise suspicion for IBD. Peripheral eosinophilia and male sex are associated with EC. A significant percent of children with colonic eosinophilia do not have colonic disease. Eosinophils/high-power field is not reliable to differentiate etiologies. Repeat colonoscopies may be required to reach final diagnoses.

Eosinophilic colitis in children

INTRODUCTION

Eosinophilic colitis, which is a rare form of eosinophilic gastrointestinal diseases, occurs as primary and secondary allergic eosinophilic colitis of the gastrointestinal tract infection, inflammatory bowel disease, celiac disease, and vasculitis. The diagnosis is based on a significant amount of eosinophils in the inflammatory infiltrate of the colon wall.

AIM

To analyze the clinical picture taking into account comorbidities and endoscopic picture in children with eosinophilic colitis.

MATERIAL AND METHODS

The test group consisted of 43 children, the average age - 12.1 years diagnosed with eosinophilic colitis (according to the Whitington scale) hospitalized in the Gastroenterology Unit, Department of Pediatrics of the Medical University of Silesia in Katowice. Testing for food allergies, celiac disease, inflammatory bowel disease, gastrointestinal diseases and parasitic diseases was performed in the group of children and the analysis concerned the intensity of eosinophilic infiltration of the colon mucosa with the severity of clinical symptoms, endoscopic picture, the presence of inflammatory bowel disease, and food allergy.

RESULTS

Half of the tested children suffered from isolated eosinophilic colitis but the rest of them had eosinophilic infiltrate with inflammatory bowel disease more often, however, the Crohn's disease. The endoscopic image was uncharacteristic, and grade III in the Whitington scale was predominant in the histopathological examination, in most cases located in the entire large intestine. The higher level of total IgE was found in less than half of the patients and it did not correlate with the severity of eosinophilic infiltration. It was shown that the severity of eosinophilic infiltration correlated with exacerbation of clinical symptoms, endoscopic image, and the presence of inflammatory bowel disease. The higher level of antibodies of ASCA and ANCA was found in approximately 20% of the children with isolated eosinophilic colitis and 63% of children with Crohn's disease.

CONCLUSIONS

The higher concentration of total IgE in less than half of the patients with eosinophilic colitis indicates the need for improving allergy diagnosis also in terms of IgE-independent allergy. The presence of higher levels of antibodies of ASCA and ANCA in some of the patients with isolated eosinophilic colitis indicates the need for further observation for the occurrence of inflammatory bowel disease.

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.

Mast cells and basophils are essential for allergies: mechanisms of allergic inflammation and a proposed procedure for diagnosis

The current definition of allergy is a group of IgE-mediated diseases. However, a large portion of patients with clinical manifestations of allergies do not exhibit elevated serum levels of IgE (sIgEs). In this article, three key factors, ie soluble allergens, sIgEs and mast cells or basophils, representing the causative factors, messengers and primary effector cells in allergic inflammation, respectively, were discussed. Based on current knowledge on allergic diseases, we propose that allergic diseases are a group of diseases mediated through activated mast cells and/or basophils in sensitive individuals, and allergic diseases include four subgroups: (1) IgE dependent; (2) other immunoglobulin dependent; (3) non-immunoglobulin mediated; (4) mixture of the first three subgroups. According to our proposed definition, pseudo-allergic-reactions, in which mast cell or basophil activation is not mediated via IgE, or to a lesser extent via IgG or IgM, should be non-IgE-mediated allergic diseases. Specific allergen challenge tests (SACTs) are gold standard tests for diagnosing allergies in vivo, but risky. The identification of surface membrane activation markers of mast cells and basophils (CD203c, CCR3, CD63, etc) has led to development of the basophil activation test (BAT), an in vitro specific allergen challenge test (SACT). Based on currently available laboratory allergy tests, we here propose a laboratory examination procedure for allergy.

Contact allergic gastritis: an underdiagnosed entity?

Only a few cases of contact allergic gastritis in patients with nickel allergy have been reported. We report a case of probable contact-allergic gastritis in a 46-year-old woman. Clinical examination revealed lichenoid mucosal lesions of the gums adjacent to bridges and crowns that had been implanted several weeks back. Since implantation, the patient had suffered from gastrointestinal complaints (including stomach pain). Gastroscopy showed eosinophilic gastritis. Patch testing done under the diagnosis of contact allergic stomatitis showed positive reactions to: gold sodium thiosulphate; manganese (II) chloride; nickel (II) sulphate; palladium chloride; vanadium (III) chloride and zirconium (IV) chloride. The crowns and bridge contained gold, palladium and zirconium chloride, hence they were replaced by titan-based dentition. Shortly after replacing the artificial dentition, all gastrointestinal symptoms resolved spontaneously without further treatment. Delayed-type allergy against the components of artificial dentition seemed to be the cause of gastritis.

Effects of probiotics, probiotic DNA and the CpG oligodeoxynucleotides on ovalbumin-sensitized Brown-Norway rats via TLR9/NF-κB pathway

The aim of the study was to investigate the effect of living probiotics, probiotic DNA and the synthetic oligodeoxynucleotides containing CpG motifs (CpG-ODN) on both immune response and intestinal barrier function in ovalbumin-sensitized rat and the underlying mechanisms. Brown-Norway rats were orally sensitized with ovalbumin, and living probiotics, probiotic DNA extraction, synthetic CpG-ODN or non-CpG ODN control was administered. In the living probiotics, probiotic DNA and CpG-ODN groups, the allergic response was significantly inhibited, the Th1/Th2 cytokine balance was shifted away from Th2 side, the percentage of CD4(+) CD25(+high) Treg cells was increased, and the intestinal barrier function was improved. The levels of toll-like receptor (TLR) 9 mRNA and nuclear factor (NF)-κB activity, as well as the IκB-α phosphorylation (p-IκB-α) was significantly increased in these three intervention groups compared with the OVA-positive group, whereas no such effects were found in the non-CpG ODN control group. These data show that the probiotic genomic DNA and the synthetic CpG-ODN was comparable with living probiotics in preventing food allergic response by immune modulation and intestinal barrier function enhancement, and the activation of TLR9/NF-κB signal pathway might be involved in this process.

Eosinophilic gastrointestinal disorders (EGID) with peripheral eosinophilia: a retrospective review at Mayo Clinic

BACKGROUND AND AIMS

Hypereosinophilic syndrome (HES) is defined by significant eosinophilia (>1,500 eos/μl), which often leads to end-organ damage/dysfunction. It is unclear if the presence of significant peripheral eosinophilia (>1,500 eos/μl) indicates a more aggressive form of eosinophilic gastrointestinal disorder (EGID).

METHODS

A database query of the Mayo Clinic Rochester electronic records (1995-2008) was performed using several search terms for eosinophilic gastrointestinal disease, and 161 records were reviewed. Patients under 18 years age, those without Mayo-reviewed pathology specimens, those with eosinophilic esophagitis only, and/or those with evidence of secondary etiologies for GI eosinophilia were excluded. A total of 39 were found to have primary EGID. We compared individuals with biopsy-proven primary EGID based on whether they had significant peripheral eosinophilia (≥1,500 eos/μl) (group A) or not (group B).

RESULTS

Group A tended to have more atopy (A: 12/15; B: 11/24; p = 0.03) and more extensive segmental involvement of the GI tract (p = 0.001). None with available studies had evidence of cardiac (A: 7/15; B: 6/24) or bone marrow (A: 10/15; B: 6/24) involvement. The two thromboembolic events in group A after diagnosis did not translate to significantly greater risk (HR = infinity, p = 0.13; group A vs. B). Doses of initial (A: 40 mg/day; B: 55 mg/day; p = 0.17) and maintenance prednisone (A; 8.75 mg/day; B: 7.5 mg/day; p > 0.90) were similar. Group A was significantly more likely to need maintenance prednisone (77 vs. 8%, p = 0.001), with a median treatment duration of 52 weeks. Recurrence of symptoms (and peripheral eosinophilia) during prednisone taper was common in both groups. Prednisone-sparing agents (hydroxyurea, imatinib mesylate, interferon (IFN)-α2b, anti-interleukin (IL-5) monoclonal antibody) were more commonly used in group A (73 vs. 8%; p < 0.0001).

CONCLUSIONS

EGID with peripheral eosinophilia ≥1,500/μl is associated with atopy, greater GI segmental involvement, and uncertain risk of thrombosis. The common use of long-term steroids and variable responsiveness to nonsteroidal agents, particularly in group A, underscores the need for targeted therapies.

Low-dose gamma-rays and simulated solar particle event protons modify splenocyte gene and cytokine expression patterns

The goal was to investigate the T helper (Th) response in splenocytes of mice exposed to low-dose/low-dose-rate (LDR) γ-rays, simulated solar particle event protons (sSPE), or combination of both. C57BL/6 mice were exposed to LDR γ-radiation ((57)Co) to a total dose of 0.05 Gray (Gy) at 0.024 cGy/h, either with or without subsequent exposure to 2 Gy sSPE protons. Expression of genes related to Th cells was evaluated immediately after exposure (day 0). On day 21, intra- and extracellular cytokine production was assessed after activation with anti-CD3 monoclonal antibodies (mAb) or phorbol 12-myristate 13-acetate/ionophore (PMA/I). Five genes were significantly modulated on day 0 in one or more of the irradiated groups compared to controls (p < 0.05): Ccl11, Ccr5, Cd80, Inha, and Il9. On day 21, numbers of cells positive for interferon-γ were high in the LDR + sSPE group versus 0 Gy and LDR γ-rays (p < 0.05), but there was no difference in IL-2 and TNF-α. Levels of secreted cytokines after anti-CD3 mAb activation were high for 5 (MIP-1α, GM-CSF, IFN-γ, TNF-α, IL-13) and low for 2 (IL-7, IL-9) in all irradiated groups. Priming with LDR photons had a significant effect on IFN-γ and IL-17 compared to sSPE protons alone; IL-2 was low only in the LDR + sSPE group. The cytokine patterns after anti-PMA/I activation were different compared to anti-CD3 mAb and with fewer differences among groups. The data show that total-body exposure to space-relevant radiation has profound effects on Th cell status and that priming with LDR γ-rays can in some cases modulate the response to sSPE.

Histopathologic diagnosis of eosinophilic conditions in the gastrointestinal tract

Eosinophils, a constitutive component of the columnar-lined gastrointestinal tract, play an essential role in allergic responses and parasitic infections. The tissue density of these cells also increases in a variety of conditions of uncertain etiology. With the exception of the esophageal squamous epithelium, in which no eosinophils are normally present, the population of normal eosinophils in the remainder of the luminal gut is poorly defined. Therefore, histopathologists must rely on their subjective judgment to determine when a diagnosis of eosinophilic gastritis, enteritis, or colitis should be rendered. Eosinophilic esophagitis is currently the best defined and most studied eosinophilic condition of the digestive tract; therefore, the confidence in accurate diagnosis is increasing. In contrast, the characteristic clinicopathologic features of eosinophilic conditions affecting other parts of the digestive tract remain somewhat elusive. This review was designed to present pathologists with simple and practical information for the biopsy-based histopathologic diagnosis of eosinophilic esophagitis, gastritis, enteritis, and colitis. It was prepared by critically reviewing more than 200 articles on the topic, along with incorporating evidence accumulated through our own collective experience. We anticipate that by increasing pathologists' confidence in reporting these abnormal but often nameless eosinophilic infiltrates, we can help better define and characterize their significance.

Food allergy and eosinophilic gastroenteritis and colitis

PURPOSE OF REVIEW

Eosinophilic gastroenteritis (EGE) and eosinophilic colitis (ECO) are two forms of chronic inflammatory disorders of the gastrointestinal tract characterized by eosinophil accumulation in the mucosa or in deeper layers of the gastrointestinal wall and associated with atopic disease. The eosinophilic gastrointestinal diseases broadened the spectrum of atopic gastrointestinal disorders formerly restricted to food allergy manifestating at the gastrointestinal mucosa. Their awareness increased enormously; therefore, we will review current knowledge about atopic gastrointestinal diseases for the allergologist.

RECENT FINDINGS

Major attention will be drawn to the differential diagnosis, because symptoms of atopic gastrointestinal diseases frequently mimic those of other chronic inflammatory bowel diseases (IBDs) or irritable bowel syndrome (IBS), although the diseases are distinct in their histopathology, gene expression signature, response to therapy, and association with allergies. The pathogenesis of EGE and ECO will be described that involves environmental and genetic factors, particularly food antigens and expression level of interleukin (IL)-5 and selective chemokines.

SUMMARY

Understanding symptoms and pathology of such disease is the basis of a rational treatment based on reduced exposure to offending food antigens as well as anti-inflammatory therapy. Atopic gastrointestinal diseases are in many cases reversible; however, chronic treatment is often necessary to prevent relapse.