Seroreactivities against Saccharomyces cerevisiae and Mycobacterium avium subsp. paratuberculosis p35 and p36 antigens in Crohn's disease patients.

Crohn's disease (CD) is an idiopathic chronic inflammatory bowel disease (IBD). Accurate diagnosis of the disease is of great clinical importance to assess its prognosis and success of therapy. Recent studies have validated and confirmed the potential utility of anti-Saccharomyces cerevisiae (baker's yeast; ASCA) IgG/IgA antibodies and anti-M. avium ss. paratuberculosis p35/p36 antibodies, separately, as serological markers to identify patients with CD. The efficacy of these markers was evaluated in the same patients with Crohn's disease. The anti-ASCA IgA/IgG and the anti-M. avium ss. paratuberculosis p35/p36 antibodies were positive in 60% (36/60) and 86.7% (52/60) of CD patients, respectively. When all the serologic markers were considered, the sensitivity in detecting CD was increased to 95.0% (57/60); 21 of 24 ASCA-negative patients were p35/p36-positive and five of eight of p35/p36-negative patients were ASCA-positive. This investigation further establishes the utility of p35 and p36 recombinant clones for the diagnosis of CD, and reveals the complimentary role of ASCA and p35 and p36 for effective detection of CD. Larger studies are needed to investigate the combined use of these serologic markers for the diagnosis of CD.