Serological differentiation of inflammatory bowel diseases.

OBJECTIVE: In order to shorten the diagnostic procedures simple serological tests with high diagnostic value for Crohn's disease and ulcerative colitis are required. The aim of this study was therefore to evaluate the diagnostic value of a newly developed assay for the determination of antibodies to mannan of Saccharomyces cerevisiae in combination with antibodies to antigens of exocrine pancreas, goblet cells, human neutrophils and tissue transglutaminase.

METHODS: Sera from 112 patients with Crohn's disease (82 confirmed and 30 suspected cases), 65 patients with ulcerative colitis, 13 patients with indeterminate colitis, 212 patients with other diseases and 250 healthy blood donors were tested for IgA and IgG antibodies to mannan of S. cerevisiae and IgA to tissue transglutaminase by enzyme-linked immunoassays. Endomysial IgA antibodies and antibodies to antigens of exocrine pancreas, goblet cells and human neutrophils were determined by indirect immunofluorescence. Sensitivity, specificity, positive and negative predictive values of antibodies to mannan of S. cerevisiae and different antibody combinations were determined regarding the diagnosis of Crohn's disease and ulcerative colitis.

RESULTS: Antibodies to mannan of S. cerevisiae were detected in 50% of confirmed and 27% of patients suspected of having Crohn's disease. Among patients who did not have Crohn's disease only those suffering from gluten-sensitive enteropathy and primary biliary cirrhosis exhibited antibodies to mannan of S. cerevisiae (14%, 6%). With respect to antibody positivity, antibodies to mannan of S. cerevisiae and/or antibodies to antigens of exocrine pancreas combined with tissue transglutaminase antibody negativity yields a sensitivity, specificity, positive and negative predictive value of 60%, 100%, 100% and 90%, respectively, regarding diagnosis of Crohn's disease.

CONCLUSIONS: Determination of antibodies to mannan of S. cerevisiae as a new marker for Crohn's disease is helpful for the differential diagnosis of inflammatory bowel disease. In combination with other established serological markers, antibodies to mannan of S. cerevisiae improve their diagnostic and predictive values considerably.