Lamina propria eosinophils and mast cells in ulcerative colitis: comparison between Asians and Caucasians.

To investigate the theory of hypersensitivity in the colonic mucosa of Asian patients with ulcerative colitis the rectal biopsy specimens of Asian and Caucasian patients presenting with colitis were selectively stained for both eosinophils and mast cells. Comparisons between ethnic groups were made as well as the correlation to the blood eosinophil count and two variables of active ulcerative colitis--the blood leucocyte count and serum orosomucoid concentration. No correlation was found in either group between circulating and tissue eosinophils and no ethnic difference was identified in the lamina propria differential cell densities. The leucocyte count and serum orosomucoid concentrations, however, were significantly higher in the Caucasians. In the Asian group a strong negative association was found between the lamina propria eosinophil density and serum orosomucoids; in the Caucasian group there was a positive association between all blood variables. It is concluded that different mechanisms occur in the two ethnic groups and in Asians these might not be reflected by the more orthodox indices of colonic inflammation.