Increased populations of endocrine cells in Crohn's ileitis.

Hyperplasia of nerves has been described previously in Crohn's disease. To determine whether similar alteration of the enteric endocrine system occurs, endocrine cells of the ileal epithelium were quantified in typical cases of the disease. In the ileum from patients with Crohn's disease, there was an increase in the endocrine cell population, as visualised by immunostaining of chromogranin. Quantification of endocrine cell numbers showed significant increases in both macroscopically uninvolved (i.e. histologically normal) (35.0 +/- 3.8, cells per unit length of muscularis mucosae mean +/- SEM, P less than 0.05) and involved (44.5 +/- 5.5, P less than 0.01) Crohn's disease samples, compared with normal controls (23.7 +/- 3.4). Although individual types of endocrine cell showed slight increases in Crohn's samples, only the enterochromaffin cells in abnormal bowel showed a significantly greater population (normal controls 10.5 +/- 2.3; involved Crohn's 21.3 +/- 4.4, P less than 0.05).