Sucrase-isomaltase expression in chronic ulcerative colitis and dysplasia☆☆☆

Abstract Sucrase-isomaltase (SI) is a mucosal disaccharidase that is present in normal small intestine and fetal colon. It also has been noted in colonic adenomas and adenocarcinomas. We used a polyclonal antibody to human SI to investigate enzyme presence and utility in detecting dysplastic changes in chronic ulcerative colitis. Sections from 32 cases were reviewed for the presence or absence of active colitis and dysplasia. Immunustaining of these cases for SI was performed and the results were reported based on locationof immunoreactivity (ie, membrane and cytoplasmic staining in superficial and crypt epithelial cells) and percentage of positivity. Of 81 sections examined, 48 were rated negative for dysplasia (23 inactive colitis, 20 active, and five probably negative) and 28 were rated positive (eight low grade and 20 high grade). Surface membrane staining of epithelial cells was noted in all 28 dysplastic slides and positive cases (sensitivity, 100%) but also in 29 of 48 negative sections ( P P