Significance of eosinophil and mast cell counts in rectal mucosa in ulcerative colitis. A prospective controlled study.

Eosinophil and mast cell counts were done in 44 patients with active ulcerative colitis, 10 patients with ulcerative colitis in remission, and 44 matched subjects with functional bowel disorder. Mean (+/- SD) rectal eosinophil counts (EC) per unit area were significantly high (P less than 0.01) in active ulcerative colitis (5.80 +/- 5.49) as compared with inactive disease (2.81 +/- 2.19) or controls (3.01 +/- 1.67). Eosinophil count was not significantly different in the acute stage between responder (6.36 +/- 5.95) and nonresponders (5.1 +/- 5.84) to medical treatment and was thus of little discriminatory and prognostic value. Mean (+/- SD) EC was reduced from 6.36 +/- 5.95 to 3.91 +/- 3.19 in responders after four weeks of medical treatment. There was little change in the EC with treatment in nonresponders. No correlation was seen between tissue eosinophils and clinical severity of ulcerative colitis. Mast cell count was not significantly different between patients with active ulcerative colitis, inactive disease, and controls and thus had little diagnostic or prognostic value. It can be concluded therefore, that EC in the rectal mucosa indicated activity but not severity of ulcerative colitis. A reduction in EC possibly indicated remission. Rectal EC, however, cannot correctly prognosticate the treatment response and outcome of the disease.