Original contributionHistologic analysis of eosinophils and mast cells of the gastrointestinal tract in healthy Canadian children☆
Introduction
Eosinophils (EOs) are normally observed in the mucosa of respiratory [1], lower genitourinary, and gastrointestinal (GI) tract locations, with the exception of the normal esophagus, which has no EO localization [2]. The precise function of EO in the GI tract is not fully understood, but it is known that they have a role in the mucosal immune response [3]. The number of intramucosal EO is known to be widely variable among individuals depending on age [4], exposure to food allergens, and exposure to infectious agents [5]. Aeroallergens can also induce GI mucosal eosinophilia [6]. Mast cells (MCs) are thought to be prototypes of innate immune cells, and their activation has been implicated in many types of neuroinflammatory responses and related disturbances of gut motility [7]. Quantification of colorectal EO and MC in healthy pediatric populations in 2 studies from the United States [8], [9] established that EO counts also vary by geographic location of residence. To the best of our knowledge, there are no studies that have quantified and qualified EO and MC from upper and lower GI tract endoscopic biopsies in a Canadian pediatric population.
The diagnosis of eosinophilic mucosal diseases is largely based on numeration of EO in GI mucosal biopsies and, to a lesser extent, their distribution. Without reference standards, this renders the diagnosis of abnormal GI eosinophilia subjective. Establishing normal values and distribution of EO and MC in a pediatric population in central Canadian geographic location is of importance and the focus of this study.
Section snippets
Study design
This study was approved by the Children's Hospital of Eastern Ontario (CHEO) Ethics Board. Pathology reports and medical records of patients who underwent a GI biopsy at CHEO between April 2013 and April 2014 were collected and reviewed. Data were extracted on patient demographics (eg, sex, age) and clinical information (eg, indication for biopsy, diagnosis). Study inclusion criteria were as follows: age younger than 18 years, normal macroscopic visualization of the mucosa during endoscopy, no
Patient characteristics
A total of 653 GI biopsies were performed at CHEO between April 2013 and April 2014; however, only 356 biopsies from 38 patients (22 females and 16 males) from endoscopically normal mucosa in healthy patients were studied that met the inclusion criteria. The median age of included patients was 13 (range, 1-17) (Table 1). Indications for endoscopic biopsy included abdominal pain (n = 12; 31.6%), rectal bleeding (n = 9; 23.7%), chronic diarrhea (n = 3; 7.9%), vomiting (n = 1; 2.6%), recurrent perianal
Discussion
In our study, we found EO counts ranged widely between the different tissues and locations (lamina propria, surface epithelium, crypts/glandular epithelium) throughout the GI tract, with gradual increases from the stomach to the cecum and then gradual decreases from the cecum to the rectum. MCs were present throughout the entire GI tract in the lamina propria of biopsy tissues, and the majority of examined biopsies did not show a high degree of preserved polarity.
Regional variation in EO along
Study impact/conclusion
This study is the first of its kind in Ontario and Canada to set the baseline count and distribution for normal EO and MC in the GI tract in the pediatric population of eastern Ontario. We can conclude that, at baseline, EO and MC are located throughout the GI tract in the lamina propria, with only limited distribution in the surface epithelium or crypt/glandular epithelium. Additionally, counts are tissue specific, with distribution highest in the proximal colon (highest overall value in the
Supplementary data
The following are the Supplementary data to this article.
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Standardized Quantification of Mast Cells in the Gastrointestinal Tract in Adults
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2022, Human Pathology ReportsCitation Excerpt :Second, use of “eosinophilia” enables pathologists to bridge the gap between the upper limits of normal ranges and the proposed thresholds for Non-EoE EGIDs [18,27]. This gap can be as wide as 3–4 standard deviations (SD) above the potential upper limits of gastrointestinal eosinophils in normal populations (either pediatric or adult) in some studies [5,23–26]. Third, it is more consistent with the grading concepts in 2012 ICOG-EO Classification System which uses “eosinophilia” for > 500 eosinophils/ul and “hypereosinophilia” for > 1,500 eosinophils/ul in peripheral blood or “extensive”/“marked” in tissue infiltration of eosinophils or deposition of eosinophil granule proteins [21–22].
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2022, Journal of Allergy and Clinical ImmunologyCitation Excerpt :Notably, gastric and duodenal biopsy specimens from patients with EGIDs were also found to have significant increases in mean mast cell counts compared with biopsy specimens from patients without EGID, and work is underway to determine how to incorporate this information into practice.40 For EoC, the threshold values are complicated by the normal variation in eosinophil density in the colon, with the greatest density occurring in the cecum/right colon and the least in the sigmoid colon/rectum in some but not all studies41-44; however, threshold values for EoC are being further refined and are in use.27 Excess eosinophils could be considered as a multiple of the peak eosinophil count per hpf in normal biopsies (eg, 2 × normal eosinophils/hpf by location)27,45; however, because of the segmental grading of eosinophil load,41-44 the location of sampling is important to report.
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2020, Surgical Pathology ClinicsCitation Excerpt :Owing to the lack of quantitative criteria for normal mucosal eosinophils in the stomach and intestines, the use of qualitative criteria is a reasonable approach. In the stomach, eosinophils are normally distributed singly in the lamina propria of the deep mucosa.4–6 The small intestine tends to have lower numbers of lamina propria eosinophils compared with the colon5,6; rare single intraepithelial eosinophils are a part of the normal inflammatory milieu of the intestines.
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Disclosures: This study was not funded. The authors have indicated they have no financial relationships relevant to this article to disclose. The authors have indicated that they have no potential conflicts of interest to disclose.