Altered lectin binding by colonic epithelial glycoconjugates in ulcerative colitis and Crohn's disease.

Evidence is accumulating that colonic mucin glycoconjugates are altered in ulcerative colitis. In order to investigate this further, the lectin-binding properties of rectal glycoconjugates have been studied in ulcerative colitis, Crohn's disease, and controls using lectin-peroxidase histochemistry. Ten lectins were used including peanut agglutinin (PNA) which is known to bind to malignant and adenomatous but not normal colonic mucins. Eight of 21 ulcerative colitis rectal biopsies and 10 of 17 Crohn's disease rectal biopsies showed PNA positivity, particularly in the supranuclear region of surface epithelial cells. There was no correlation between PNA positivity and duration of disease or inflammation, and none of the biopsies showed evidence of dysplasia. This abnormality in epithelial cell glycoconjugates seems to be commonly present in nondysplastic mucosa and occurs in both ulcerative colitis and Crohn's disease. It may reflect a fundamental abnormality in mucus glycoprotein synthesis in inflammatory bowel disease.