A vascular hypersensitivity model of acute multifocal gastrointestinal infarction

We have investigated the hypothesis that submucosal vasculitis may account for the patchy transmural inflammation observed in Crohn's disease. Test ferrets (N = 11) were sensitized to human albumin. Five days after the last sensitization injection, human albumin microspheres (15-150 microns diameter) were injected intraarterially into the mesenteric circulation of a defined loop of mid-gut. Six control ferrets showed no histological abnormality at either 48 hr or two weeks after intraarterial injection. At 48 hr, five of six presensitized ferrets demonstrated submucosal vasculitis with fibrinoid necrosis. In two cases there was transmural inflammation and mucosal ulceration. A further five presensitized ferrets received weekly subcutaneous human albumin injections following the mesenteric intraarterial injection of albumin microspheres: after two weeks one animal demonstrated mild perivascular inflammatory changes and another demonstrated vasculitis. One of the two animals 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-mediated submucosal vasculitis can sometimes result in discontinuous transmural inflammation of the intestinal wall.