Immunohistologic demonstration of abnormal colonic crypt cell kinetics in ulcerative colitis

A monoclonal antibody, Ki-67, that reacts with cells in the proliferative phases (G 1, G 2, S, and M) of the cell cycle was used in an immunohistochemical labeling reaction to examine the colonic crypt epithelium in active ulcerative colitis, inactive ulcerative colitis, and normal mucosa. The proportions of labeled cells in the lower two thirds (proliferative zone) and in the upper quarter of the crypt were determined. The proportions of Ki-67-positive crypt epithelial cells in both the proliferative zone and the upper crypt were higher in biopsy specimens from patients with active ulcerative colitis than from patients with normal mucosa or with inactive ulcerative colitis. In inactive ulcerative colitis the proportion of Ki-67-positive epithelial cells in the proliferative zone of the crypt was higher than in normal mucosa. These results are similar to those obtained in studies using tritiated thymidine to determine the proportion of cells in the DNA-synthesizing phase of the cell cycle and suggest that immunohistochemical staining with Ki-67 may be a practical method for measuring the proliferative activity of epithelial cells in patients with ulcerative colitis and other disorders of the gastrointestinal tract.