Histologic analysis of eosinophils and mast cells of the gastrointestinal tract in healthy Canadian children.

Many gastrointestinal (GI) disorders, including GI eosinophilia and inflammatory bowel disease, can be characterized by increased mucosal eosinophils (EOs) or mast cells (MCs). Normal mucosal cellular counts along the GI tract in healthy children have not been established for a Canadian pediatric population. To establish a benchmark reference, we quantified EO and MC from 356 mucosal biopsies of the GI tract obtained during upper and lower endoscopic biopsies of 38 pediatric patients in eastern Ontario. Mean total counts of EO varied for the 11 tissues we examined, from a low of 7.6±6.5/high-power field (HPF) (×40 [×400, 0.55mm(2)]) in the body of the stomach to a high of 50.3±17.4/HPF in the cecum. The lower GI tract (ileum, cecum, colon, sigmoid, and rectum) generally had higher total EO counts than the upper GI tract (antrum and body of stomach, duodenum, and duodenal cap) (combined average of 32.1±20.6 versus 19.3±15.8, respectively). Similarly, the number of mucosal MC was different in the various regions of the GI tract ranging from 0.04±0.2/HPF in the duodenal cap to 0.9±2.6/HPF in the ileum. Total counts for EO and MC in the lamina propria were not significantly different between sexes when adjusted for multiple testing. EO polarity was absent in many cases, irrespective of the GI region. These numeration and localization of EO and MC will provide normative data for upper and lower endoscopic GI biopsies in the pediatric population of Eastern Ontario.