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

Quantification of eosinophil densities in the oesophagus, stomach and small bowel of adults: A review of endoscopic and surgical specimens with normal histology, Free State Province, South Africa

AIM

Studies defining eosinophil densities in the gastrointestinal tract (GIT) are limited. To assess whether eosinophils are pathologically infiltrating the GIT, it is important to evaluate eosinophil densities for specific populations.

METHODS

A retrospective, quantitative, comparative study was conducted to determine the number of eosinophils in the oesophagus, stomach and small bowel of patients in central South Africa and to investigate whether a statistically significant difference occurred between ethnic and gender groups.

RESULTS

In total, 309 histological sections from the oesophagus, gastric corpus, gastric antrum and small intestine were sampled from male and female, African and Caucasian patients. Histology reports and review of the slides confirmed the absence of histological abnormality. The number of eosinophils in the epithelium and lamina propria were manually quantified. The eosinophil values across gender, ethnicity and location were 0-2.0/mm² for the oesophagus, 0-53.0/mm² for the gastric corpus and 7.1-115.3/mm² for the small intestine. Regarding the gastric antrum, African and Caucasian females had eosinophil values of 1.0-35.7/mm² and 0-22.4/mm², respectively. Males had an eosinophil density of 0-31.6/mm² in the gastric antrum. The eosinophil values in the oesophagus, gastric corpus and small bowel were not significantly different between genders and ethnic groups. The only site where ethnicity influenced the number of eosinophils was the gastric antrum, a discrepancy that cannot be explained.

CONCLUSION

To the authors' knowledge, this is the first report on the eosinophil densities in the oesophagus, stomach and small bowel of adults in South Africa.

Clinicopathologic Characterization of Lymphocytic Colitis in the Pediatric Population

BACKGROUND

Lymphocytic colitis (LC) in the pediatric population has been associated with immune dysregulation.

METHODS

Single-center retrospective study of pediatric LC.

RESULTS

50 patients (35 female, 70%) with a median age of 12 years at diagnosis (interquartile range: 5.7-15.8) of LC were identified. At presentation, 11 patients (22%) had malnutrition, 16 (32%) had a known underlying immune dysregulation, 4 (8%) had celiac disease (CD), and none had a diagnosis of inflammatory bowel disease. The most common medications prior to diagnosis were non-steroidal anti-inflammatory drugs, proton pump inhibitor, and selective serotonin reuptake inhibitors (10% each). Colonic biopsies showed a median number of intraepithelial lymphocytes (IELs)/100 epithelial cells of 48 (range: 25-85), and only 10% of cases had neutrophilic cryptitis. Upper gastrointestinal tract findings included lymphocytic esophagitis (4%), and duodenal IELs without and with villous blunting (9% each) (n: 47). Ten patients (23%) had increased IELs in the terminal ileum (n: 43). Treatments including 5-ASA, budesonide, prednisone, and gluten-free diet improved symptoms in <50% of patients (n: 42), and all follow-up colonoscopies showed persistent LC (n: 13).

CONCLUSION

Our study supports the association of LC with immune-mediated conditions, most commonly celiac disease. Symptomatic improvement was seen in <50% of patients with none of the patients with repeat colonoscopy showing histologic improvement.

Nonatopic Eosinophilic Duodenitis in an Adult: A Case Report and Overview

Eosinophilic duodenitis is an inflammation of the duodenum, characterized by an abundance of eosinophils, typically triggered by hypersensitivity reactions. Typically, recurrent abdominal pain with eosinophilic duodenitis is rare in individuals without a history of atopic conditions like asthma. Here, we present the case of a 62-year-old man who experienced recurrent upper abdominal pain for 12 months and unintended weight loss for the past six months. The patient reported no allergies to food, drugs, or the environment, and has no history of other atopic conditions. Esophagogastroduodenoscopy (EGD) with biopsy of the duodenum and stomach revealed 32 eosinophils per high-power field (HPF), which is mild. Skin prick testing yielded negative results. Following initial treatment with H2 inhibitors, proton pump inhibitors, and budesonide for a total of 12 weeks, the patient reported an improvement in symptoms and subsequent weight gain. This report emphasizes a rare case of eosinophilic duodenitis in a nonatopic individual with a successful treatment regimen. His quality of life improved with weight gain, resolved abdominal pain, and improved appetite. Although the patient's condition lasted about 12 months, our report showcased the importance of timely clinical diagnosis and appropriate combination therapy to alleviate progressive pain associated with eosinophilic duodenitis.

Eosinophilic gastroenteritis: Pathogenesis, diagnosis, and treatment

ABSTRACT

Eosinophilic gastroenteritis (EGE) is a gastrointestinal disorder of unclear etiology that is characterized by eosinophilic infiltration of the stomach and small intestine, and consists of mucosal, muscular, and serosal subtypes. Eosinophilic infiltration of the gastrointestinal tract is a fundamental histopathological characteristic of EGE and is driven by several T-helper type 2 (Th2)-dependent cytokines and induced by food allergy. Due to the lack of a diagnostic gold standard, EGE has a high rate of delayed diagnosis or misdiagnosis. However, several new diagnostic strategies have been developed, such as novel genetic biomarkers and imaging tests. Although dietary therapy and corticosteroids remain the common choices for EGE treatment, recent decades have seen the emergence of novel treatment alternatives, such as biologics that target particular molecules involved in the pathogenic process. Preliminary investigations and clinical trials have demonstrated the efficacy of biologics and provided additional insights for the era of refractory or corticosteroid-dependent EGE biologics.

Immune Activation in Functional Dyspepsia: Bystander Becoming the Suspect

Disorders of gut-brain interaction (DGBI), formerly termed functional gastrointestinal disorders (FGID), are highly prevalent although exact pathophysiological mechanisms remain unclear. Intestinal immune activation has been recognized, but increasing evidence supports a pivotal role for an active inflammatory state in these disorders. In functional dyspepsia (FD), marked eosinophil and mast cell infiltration has been repeatedly demonstrated and associations with symptoms emphasize the relevance of an eosinophil-mast cell axis in FD pathophysiology. In this Review, we highlight the importance of immune activation in DGBI with a focus on FD. We summarize eosinophil biology in both homeostasis and inflammatory processes. The evidence for immune activation in FD is outlined with attention to alterations on both cellular and molecular level, and how these may contribute to FD symptomatology. As DGBI are complex and multifactorial conditions, we shed light on factors associated to, and potentially influencing immune activation, including bidirectional gut-brain interaction, allergy and the microbiota. Crucial studies reveal a therapeutic benefit of treatments targeting immune activation, suggesting that specific anti-inflammatory therapies could offer renewed hope for at least a subset of DGBI patients. Lastly, we explore the future directions for DGBI research that could advance the field. Taken together, emerging evidence supports the recognition of FD as an immune-mediated organic-based disorder, challenging the paradigm of a strictly functional nature.

Pathologist's approach to paediatric and neonatal eosinophilic gastrointestinal disorders

Children are not simply miniature adults. The evaluation of their gastrointestinal disorders is therefore different from that in full-grown adults and requires a particular clinical/pathologic approach.

Different studies have tried to assess the normal eosinophil distribution in the gastrointestinal tract in adults while very few studies have investigated the paediatric population, consequently complicating the pathologist’s ability in identifying an abnormal number of eosinophils in this setting of patients.

When evaluating gastrointestinal tract biopsies with eosinophilia, eosinophilic count must be considered along with other histological features like eosinophil distribution in the gastrointestinal wall, their degranulation, cryptitis and crypt abscesses, other accompanying inflammatory cells, apoptotic bodies, foreign material or microorganisms; these findings, although rarely specific, may be a useful aid for diagnosis.

Reports should not include a diagnosis of primary eosinophilic gastrointestinal disorders (EoGID) if clinical data and test results do not rule out other forms of gastrointestinal eosinophilia. A more descriptive definition like “with eosinophilic pattern” should be favoured over a specific diagnosis of “eosinophilic disorder” in order to avoid potential confusion between different entities.

Intestinal eosinophils: multifaceted roles in tissue homeostasis and disease

Intestinal eosinophils are largely considered to be one of the central immune effector cells during helminth infection and disorders such as eosinophilic oesophagitis and food allergies. Given the abundance of these cells present in the gastrointestinal tract at homeostasis, emerging studies now reveal novel roles for eosinophils in the development and regulation of immunity, and during tissue repair. In addition, the identification of distinct eosinophil subsets indicates that we must consider the heterogeneity of these cells and how they differentially participate in mucosal immunity at steady state and during disease. Here, we summarise the literature on intestinal eosinophils, and how they contribute to mucosal homeostasis through immune regulation and interactions with the microbiome. We then explore the divergent roles of eosinophils in the context of eosinophilic gastrointestinal disorders and during helminth infection, whereby we discuss key observations and differences that have emerged from animal models and human studies. Lastly, we consider the possible interactions of eosinophils with the enteric nervous system, and how this represents an exciting area for future research which may inform future therapeutic targets.