A VASCULAR HYPERSENSITIVITY MODEL OF ACUTE MULTIFOCAL GASTROINTESTINAL INFARCTION

We have investigated the hypothesis that submucosal vasculitis may acc ount for the patchy transmural inflammation observed in Crohn's diseas e. Test ferrets (N = 11) were sensitized to human albumin. Five days a fter the last sensitization injection, human albumin microspheres (15- 150 mum diameter) were injected intraarterially into the mesenteric ci rculation of a defined loop of mid-gut. Six control ferrets showed no histological abnormality at either 48 hr or two weeks after intraarter ial injection. At 48 hr, five of six presensitized ferrets demonstrate d submucosal vasculitis with fibrinoid necrosis. In two cases there wa s transmural inflammation and mucosal ulceration. A further five prese nsitized ferrets received weekly subcutaneous human albumin injections following the mesenteric intraarterial injection of albumin microsphe res: after two weeks one animal demonstrated mild perivascular inflamm atory changes and another demonstrated vasculitis. One of the two anim als with transmural inflammation and mucosal ulceration at 48 hr, and the animal with vasculitis at two weeks, had precipitating antibodies to human serum albumin. This model demonstrates that an immune-mediate d submucosal vasculitis can sometimes result in discontinuous transmur al inflammation of the intestinal wall.