Increased Mast Cell Counts and Degranulation in Microscopic Colitis

Zhikai Chi; Jing Xu; Romil Saxena

doi:10.1155/2020/9089027

Increased Mast Cell Counts and Degranulation in Microscopic Colitis

Gastroenterol Res Pract. 2020 Jan 4:2020:9089027. doi: 10.1155/2020/9089027. eCollection 2020.

Authors

Zhikai Chi¹, Jing Xu¹, Romil Saxena²

Affiliations

¹ Department of Pathology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
² Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA.

Abstract

Objectives: Microscopic colitis (MC) is characterized by chronic diarrhea, normal colonoscopy findings, and mucosal inflammation in colonic biopsies and can be classified as collagenous colitis (CC) or lymphocytic colitis (LC). However, the pathogenesis of MC is largely unknown. In this study, we aimed to study mast cell counts and activation in MC.

Methods: We investigated 64 biopsy samples from the surgical pathology database of Indiana University Health, which met the diagnostic criteria for CC or LC along with 20 control samples collected from 2014 to 2015. The specimens were used for the quantification of mast cells by examining the presence of intracellular and extracellular tryptase by immunohistochemistry.

Results: In the lamina propria, the mast cell count was higher in both CC and LC groups than the control (mean highest count, 39/high-power field (HPF) vs. 30/HPF vs. 23/HPF; P < 0.01). Extracellular tryptase was present in 10% of control subjects as compared to 41% of CC (P < 0.01). Extracellular tryptase was present in 10% of control subjects as compared to 41% of CC (P < 0.01). Extracellular tryptase was present in 10% of control subjects as compared to 41% of CC (.

Conclusions: The increased mast cell count and degranulation are identified in MC, suggesting that mast cell activation might be involved in the pathogenesis of MC.