Mucosal Mast Cell Distribution in the Gastrointestinal Tract of Children

Abstract

Objectives: The physiological number and distribution of mast cells (MCs) in the pediatric gastrointestinal (GI) tract is not well defined and reference values of normality are missing. To define a physiological and disease defining cut-off, a systematic histological exploration of MC distribution from the esophagus to the rectum in healthy as well as in patients with gastrointestinal food allergies (GFA) was performed. Methods: Nine pediatric subjects that exhibited unremarkable histopathological evaluations or underwent endoscopy for surveillance reasons after a previous polypectomy of single colonic juvenile polyps served as reference cohort. In all of these subjects, a chronic inflammatory disease (eg, inflammatory bowel disease, celiac disease) or allergy was excluded. In addition, a group of 15 patients with gastrointestinal complaints suspected to be caused by a GFA were investigated. Immunohistochemistry was performed from all biopsies using CD117 (c-Kit) as a reliable marker to identify MCs in the lamina propria. Results: There were distinct differences of MC counts in all parts of the pediatric GI tract. The highest counts of MCs in both symptomatic patients and control cohort, were found in the duodenum, terminal ileum, cecum and ascending colon. The lowest counts were found in the esophagus. Significant disparities between GFA and healthy subjects were found in the gastric corpus (22.1 AE 4.0/ high power field [HPF] vs 32.0 AE 10.1/HPF; P ¼ 0.034) and ascending colon (44.8 AE 10.4/HPF vs 60.4 AE 24.3/HPF; P ¼ 0.047). Conclusions: Mucosal MC counts in the pediatric GI tract are higher than previously reported, with a considerable overlap between healthy and GFA patients. These results provide detailed information on distribution and numbers of MCs in pediatric allergic patients while allowing estimates of physiological values in childhood for the first time. With regard to diagnostic procedures in GFA further laboratory parameters have to be integrated.

Mast cell evaluation in gastrointestinal biopsies: should we be counting? A critical review and practical guide for the surgical pathologist

“…The findings in these and several other studies 27,[32][33][34][35][36] that report mean mast cell counts in excess of 20/hpf at various sites in the GI tract suggest that (1) the proposed upper limit of normal of 20/HPF for mast cells in GI biopsies is not applicable to biopsies stained with CD117, and (2) there is insufficient evidence to support mast cell counting in GI biopsies as part of the diagnostic work-up for chronic diarrhoea with no identified underlying cause.…”

Identifying Mast Cells in Gastrointestinal Biopsies in Pediatric Irritable Bowel Patients

“…Our utilization of having subjects with polyps or reflux as our control cohort without any evidence of chronic abdominal pain, changes in bowel habits, and histological inflammation are not unique as these criteria have been used for control cohorts previously in both adult and pediatric literature ( 16 , 17 , 22 , 23 ). For instance, Jakate et al selected 50 subjects with non-diarrheal conditions (such as duodenal biopsies for gastroesophageal reflux, Helicobacter gastritis , gastric fundic gland polyps, and mucosa adjacent to duodenal adenomatous polyps; and colonic biopsies for melanosis and mucosa adjacent to adenomatous polyps) as their control group.…”

“…Retrospective selection of the control cohort was performed in a manner similar to previously published adult and pediatric studies (13,(16)(17)(18)(21)(22)(23). Controls were children aged 8 to 21 years old with a known diagnosis of polyposis syndrome, rectal bleeding, and/or gastroesophageal reflux who had previously undergone upper and/or lower endoscopies between January 2017 and September 2021 and had normal histology.…”

“…Due to limited surveillance endoscopy in pediatrics compared to adults, it was challenging to choose a control group to evaluate normal MC distribution. Similar to existing adult and pediatric literature (13,(16)(17)(18)(21)(22)(23), we selected patients who underwent upper and/or lower endoscopy performed for reasons other than abdominal pain and changes in bowel habits. Our control group included normal histopathological specimens from participants aged 8-21 years with known diagnoses of colorectal polyps and polyposis syndromes, including familial adenomatous polyposis syndrome, MUTYH-associated polyposis syndrome (MAP), Peutz-Jegher syndrome, familial juvenile polyposis, and PTEN hamartomatous tumor syndromes.…”

Mucosal Mast Cells as Key Effector Cells in Food Allergies

“…Intestinal mast cells are found throughout the gastrointestinal tract and normally account for 2-3% of mononuclear cells in the lamina propria. Ehrsam et al [37] have recently reported the number and distribution of mast cells in the pediatric gastrointestinal tract in healthy individuals, as well as in patients with food allergies. Importantly, mast cell hyperplasia and higher tryptase concentrations in the intestinal mucosa are associated with allergic inflammation of the mucosa in patients with food allergies and IBS [38,39].…”