CRYPT HYPERPLASIA RELATED TO INCREASED LYMPHOCYTE-ACTIVATION IN THE RECTAL MUCOSA OF CHILDREN WITH ULCERATIVE-COLITIS

The presence of cells positive for interleukin-2 receptors (CD25) and the proportion of Ki-67 positive dividing cells in the crypts were stu died with monoclonal antibodies using sensitive immuno-histochemical t echniques in the rectal biopsy specimens taken from 13 children with i nflammatory bowel disease (4 Crohn's disease and 9 ulcerative colitis) and 10 controls. In all specimens, but one, from patients CD25 + cell s were found in the surface and crypt epithelium, while in none of con trols were seen such cells. The mean percentage of dividing crypt cell s was significantly higher in ulcerative colitis (36,0%) and in Crohn' s disease (34,6%) than in controls (18,4) (p < 0.001 in both compariso ns). In ulcerative colitis, a correlation between CD25/CD3 ratios in t he surface and crypt epithelium and the percentage of dividing crypt c ells was found. We conclude that activated lymphocytes have a role in the crypt hyperplasia of ulcerative colitis.