Cellular hypersensitivity to components of intestinal mucosa in ulcerative colitis and Crohn's disease.

The migration of peripheral leucocytes in vitro is examined in 36 patients with ulcerative colitis, in 34 patients with Crohn's disease, in 12 patients with ulcerative colitis or Crohn's disease, and in 31 patients with other gastrointestinal disorders. In a majority of the patients with ulcerative colitis extracts of foetal, colonic, and jejunoileal mucosa inhibit migration of leucocytes. A similar reactivity is seldom seen in Crohn's disease. Extracts of liver, kidney, and adrenal gland do not inhibit the migration. The reactivity of the ulcerative colitis group was found to be significantly different from that in controls and in the Crohn group, whereas the Crohn group did not differ significantly from the controls. The examination thus reveals a biological difference between ulcerative colitis and Crohn's disease, which are otherwise separable mainly on nosological criteria. The finding of a similar inhibition of leucocyte migration in five out of 31 patients with miscellaneous gastrointestinal disorders unrelated to ulcerative colitis and Crohn's disease was inconclusive. An antigen-induced inhibition of leucocyte migration has been shown in vitro to be a correlate of cellular hypersensitivity. The immunological mechanisms behind the present system are discussed, and it is concluded that the reactivity observed probably indicates the existence in ulcerative colitis of a state of cellular hypersensitivity to components of normal foetal, colonic, and jejunoileal mucosa.