A search for a transmissible agent in Crohn's disease.

Controversy exists as to whether a transmissible agent is responsible for Crohn's disease. Previous reports have suggested that sarcoid-like granulomas can develop in animals following inoculation of homogenates derived from bowel affected by Crohn's disease. This study involved the injection of Crohn's tissue homogenates into experimental animals under a variety of conditions which might be expected to favour the demonstration of such an agent. Homogenates have been inoculated into the ileum of rats, mice, and rabbits and also given inoculated into ileum and footpads of rats which have previously been rendered lymphoedematous by surgical interruption of the draining lymphatics. Bowel homogenates from a total of 17 patients with Crohn's disease have been injected into 91 experimental animals. No macroscopic or microscopic changes indicative of Crohn's disease were detected. Thus study does not support the suggestion that a transmissible agent is present in Crohn's disease.