A morphological assessment of immunoreactivity in colonic Crohn's disease and ulcerative colitis by a study of the lymph nodes.

The mesenteric lymph nodes in total colectomy specimens from patients with ulcerative colitis or Crohn's colitis were assessed for immunological reactivity. Despite the suggestion of previous work using different methods that immunological difference between the diseases exist and may be important in pathogenesis, no significant differences were found in this study. Changes were observed in both diseases and when ulceration was present these consisted of both cellular and humoral immune reactivity. There was no evidence of diminished cell-mediated immunity in Crohn's disease and the presence of granulomata did not constitute any special immunological group.