Immunohistochemical analysis of the distribution of measles related antigen in the intestinal mucosa in inflammatory bowel disease

Background--Measles virus is implicated in the aetiology of Crohn's disease . This measles hypothesis is mainly supported by immunohistochemical findin gs that the measles related antigen is present in the intestine of patients with Crohn's disease. Recently we isolated this antigen from the intestine of a patient with Crohn's disease using a molecular cloning technique and produced the monoclonal antibody against it (designated 4F12). Aim--To discover whether the measles related antigen is uniquely present in Crohn's disease. Subjects/Methods-Colonic mucosa samples from 20 patients with Crohn's disea se, 20 with ulcerative colitis, 11 with non-inflammatory bowel disease (IBD ) colitis, and nine controls were immunohistochemically stained with the an ti-measles monoclonal antibody 4F12. The numbers of positive cells, the rat io of positive cells to nucleated cells, and the staining intensity of the positive cells were compared. Furthermore, the distribution of the measles antigen in other human organs was examined. Results--Both the number of positive cells and the ratio of positive cells to nucleated cells were significantly increased in Crohn's disease, ulcerat ive colitis, and non-IBD colitis compared with controls (p<0.05) but were s imilar among the three disease groups. The staining intensity of the positi ve cells was also similar among the three disease groups. Small numbers of positive cells were observed in the oesophagus, stomach, duodenum, jejunum, and lung. Conclusions--The presence of the measles related antigen in the colonic muc osa was not unique to Crohn's disease. These results, together with the obs ervation that such a measles related antigen was derived from host protein, do not support the hypothesis that measles virus causes Crohn's disease.