Introduction

Mediators released from mast cells may play a role in the development and maintenance of inflammatory bowel disease in dogs. The activation of the transmembrane receptor KIT (CD117) is critical for the function of the mast cells and the release of their mediators.

Objectives

This research aims to quantify and evaluate changes in lymphocyte subpopulations and mast cell distribution in intestinal samples of dogs with inflammatory bowel disease as useful markers for clinical diagnosis.

Methods

Lymphocyte immunophenotyping and mast cell kit receptor expression in paraffin section of formalin-fixed samples of small intestine with inflammatory bowel disease were analyzed by immunohistochemistry, and computer-assisted morphometric analysis was performed with an FSX Olympus microscope and analyzed with the software Image-Pro Plus^TM.

Results

CD3+ lymphocytes and CD117+ mast cells were detected in significantly (p<0.05) higher numbers in the upper part of lamina propria but not in the lower part or submucosa of intestinal tissue samples from dogs with inflammatory bowel disease diagnosed by clinical and histopathological changes when compared with samples from healthy dogs.

Conclusions

A higher number of infiltrative CD3+ lymphocytes in the lamina propria of the intestinal wall correlates with an increase in mast cells suggesting an altered Th1 immune response in dogs with inflammatory bowel disease. Also this investigation shows that the immunohistochemical demonstration of an increased CD117+ mast cell population could be a potential additional marker for canine inflammatory bowel disease.