In vivo assessment of granulocyte migration to diseased bowel in Crohn's disease.

It has been suggested, on the basis of impaired granulocyte migration to skin windows, that there is a fundamental granulocyte defect in Crohn's disease. In vitro tests of granulocyte function have, however, failed to confirm this. We have studied granulocyte migration to inflamed bowel in Crohn's disease using a new approach which utilises dynamic gamma camera imaging after injection of 111In labelled autologous granulocytes. In 20 of 22 studies there was rapid migration to diseased bowel, compatible with no migration delay. Only two patients showed delays in migration of 12 and 15 minutes respectively, but neither had any clinical characteristics to distinguish them from the other 20 patients. This study shows that the majority of patients with Crohn's disease in relapse have rapid granulocyte migration to diseased bowel and provides evidence against a significant migration defect in this condition.