Lectin binding in colorectal mucosa.

Lectin binding of goblet cell mucin in human colonic mucosa was studied in patients with irritable bowel syndrome, colorectal malignancy and ulcerative colitis using plant lectins, Dolichos biflorus agglutinin (DBA) and peanut agglutinin (PNA). Normal colonic mucosa demonstrated a strong binding with DBA (100%) but did not bind to PNA at all. Colonic carcinomas showed strong PNA binding (7 of 15 biopsies) while DBA binding was absent in 14 of 15 biopsies. The transitional mucosa showed reduced or absent DBA binding in 6 and positive PNA binding in 2 of 15 biopsies. During the active phase of ulcerative colitis, there was a loss of DBA binding in 10 of 15 biopsies, which was restored during remission in all. One biopsy with severe dysplasia showed PNA binding. It is concluded that normal colorectal mucosa binds DBA strongly but not PNA. Malignant tissue and transitional mucosa reveal PNA binding often, with decreased DBA binding. In ulcerative colitis DBA binding decreases during phases of activity.