INFLAMMATORY LARGE-BOWEL DISEASE IN IMMUNODEFICIENT MICE NATURALLY INFECTED WITH HELICOBACTER-HEPATICUS

Large bowel disease detected clinically by rectal prolapse was studied in 64 immunodeficient mice (37 athymic NCr-nu/nu, 12 BALB/c AnNCr-nu/ nu, 9 C57BL/6NCr-nu/nu, and 6 C.B17/Icr-scid/NCr) naturally infected w ith Helicobacter hepaticus, Rectal prolapse was found in approximately 5% of immunodeficient mice maintained in a research facility over a p eriod of 3.5 years. All mice had various degrees of chronic proliferat ive typhlitis, colitis, and proctitis, usually without concomitant hep atitis, Some mice had severe proliferative proctitis with cystic hyper plasia, Histologic study of the large bowel of 48 athymic NCr-nu/nu mi ce without H. hepaticus infection and housed in another clean facility revealed only 12% of the mice with minimal-to-mild large bowel inflam mation, Helicobacter hepaticus infection is associated with large bowe l disease in immunodeficient mice but is not seen in H. hepaticus-infe cted immunocompetent mice, This new pathogenic bacterial infection sho uld be considered as another potential cause or co-factor for rectal p rolapse and large bowel disease in mice.