Lay Summary

Proposal No. IBD-0074R
Principal Investigator: Marcel A. Behr, M.D.
Applicant Organization: McGill University Health Centre Research Institute (Montreal, Canada)
Project Title: Molecular and immunologic detection of Mycobacterium avium paratuberculosis in Crohn’s disease
Period of Award: December 1, 2003 - March 31, 2006

There are many competing and conflicting theories on the etiology of Crohn’s disease.  One of these theories is that some patients with Crohn’s have a chronic infection due to an organism known as Mycobacterium avium paratuberculosis (MAP).  However, such an association has never been convincingly demonstrated, in large part because there are no accurate tests to substantiate MAP infection in persons with Crohn’s.

This study represents the first phase of implementing tests that have been developed in the laboratory of Dr. Marcel Behr, a Mycobacterial researcher.  First, an improved way to look for bacterial DNA has been developed and validated in sheep that are infected with very low numbers of MAP bacteria.  Second, a test looking for an immune response to MAP has been developed using knowledge about the kind of immune response seen in another Mycobacterial disease, namely tuberculosis.

The goal of this study is to see whether there is evidence of MAP infection and Crohn’s disease.  If so, more extensive studies will be undertaken to determine if MAP underlies certain sub-types of Crohn’s and whether antibiotic treatment of MAP results in clinical improvement in Crohn’s patients.