Mycobacterial aetiology of Crohn's disease

Abstract

An aetiological relationship between Crohn's disease (CD) and Mycobacteria has been suggested. Recently Chiodini et al. isolated Mycobacterium (M.) sp. closely related to M. paratuberculosis, namely M. linda, from tissues of patients with CD and they reported greater seroactivity to M. paratuberculosis in patients with CD. In the present study, human intestinl tissue proteins of patients with CD, ulcerative colitis (UC), control and bovine paratuberculosis tissue proteins were analyzed for immune recognition, using transblot experiments, with anti-M. paratuberculosis antibody. Although bovine paratuberculosis tissue contains some 40-50 kilodalton proteins derived from M. paratuberculosis, CD, UC and control tissues did not contain any protein recognizable by anti-M. paratuberculosis antibody. M. paratuberculosis protoplasmic antigen was analyzed for immune recognition, using transblot experiments, with the sera of CD and control. However, there was no protein recognized specifically by sera from CD. Serum antibody titer to M. linda whole cell antigen was also evaluated using ELISA. There was no significant difference in CD, UC and control. Patients with tuberculosis had a significant increase in antibody titer (p<0.01) to M. linda compared with three other groups. No correlations were observed between antibody titer of patients with CD and activity of the disease process. The results showed no evidence for the hypothesis that M. paratuberculosis or its related species might be an aetiological agent in CD.