Lay Summary

Proposal No.  IBD-0202
Principal Investigator: Xavier Bossuyt, M.D., Ph.D.
Applicant Organization: Katholieke Universiteit Leuven (Belgium)
Project Title: Identification of target antigens of antibodies in inflammatory bowel disease
Award Period: May 1, 2007 - December 31, 2009

Sera of IBD patients often contain antibodies. These antibodies can be directed against food proteins, microbial proteins or self proteins. Atypical perinuclear anti-neutrophil cytoplasmic antibodies (pANCA) and anti-exocrine pancreas autoantibodies (PAB) are examples of antibodies against self proteins. pANCA are present in the sera of 50 to 80% of patients suffering from ulcerative colitis (UC) and in sera of 5 to 25% of Crohn’s disease (CD) patients. PAB are present in 32% of CD and 23% of UC patients and absent in healthy subjects. Current laboratory tests to detect these antibodies are labor intensive and not reproducible. A simple laboratory test for the presence of these antibodies in sera could facilitate the diagnosis of IBD. However, for the development of such laboratory tests the proteins to which the antibodies are directed have to be identified. The aim of the current project is to identify the antigen to which the antibodies are directed.

For that purpose, a technique called protein microarray will be used. A protein microarray is a slide coated with a large number (8000) of human proteins. Sera containing pANCA or PAB antibodies will be incubated with the slide. In that way, antibodies present in the sera can bind to the protein they recognize. Afterwards, the proteins to which antibodies are bound can be identified.

With this knowledge, simple laboratory tests for the detection of the IBD-specific antibodies can be developed. The test result will help the physician in making the diagnosis of IBD and possibly in differentiating between UC and CD.