Different distribution of mast cells and macrophages in colonic mucosa of patients with collagenous colitis and inflammatory bowel disease

BACKGROUND/AIMS: Chronic inflammatory cells in colonic mucosa is a histopathologic feature in patients with collagenous colitis and inflammatory bowel disease. The aim of this study was to compare the distribution of mast cells and macrophages in the colonic mucosa of patients with collagenous colitis, Crohn's disease, and ulcerative colitis. METHODOLOGY: Patients with histologically confirmed collagenous colitis (n = 13), Crohn's disease (n = 20) or ulcerative colitis (n = 20) and normal control patients (n = 20) were included in this study. Biopsy specimens were obtained from the sigmoid colon of each patient, and immunostained using antibodies to tryptase (AA1) and CD68. The number of mast cells and macrophages located in upper and lower part of the lamina propria was determined. RESULTS: The number of mast cells in the upper part of lamina propria in patients with collagenous colitis (286 +/- 89/mm2, mean +/- SD), Crohn's disease (330 +/- 84/mm2) and ulcerative colitis (355 +/- 90/mm2), was higher than normal controls (201 +/- 44/mm2). The number of mast cells in the lower part of lamina propria in patients with Crohn's disease (345 +/- 87/mm2) and ulcerative colitis (363 +/- 86/mm2) was higher than collagenous colitis (266 +/- 63/mm2) and normal controls (309 +/- 60/mm2). The number of macrophages in the lower part of lamina propria in patients with Crohn's disease (330 +/- 63/mm2) and ulcerative colitis (301 +/- 60/mm2) was higher than in collagenous colitis (247 +/- 46/mm2) and normal controls (242 +/- 52/mm2), although there were no significant differences in the number of macrophages present in the upper part of the lamina propria among the four groups. CONCLUSIONS: Our data showed the presence of a different distribution of mast cells and macrophages in collagenous colitis and inflammatory bowel disease, and these suggest that because mucosal mast cells have been implicated in the development of Th2 response collagenous colitis is more of a Th2 type reaction rather than Th1.