Antiglycan antibodies as serological markers in the differential diagnosis of inflammatory bowel disease

Background: The objective of the study was to evaluate the diagnostic accuracy of recently developed antiglycan serological tests in clinical practice for the diagnosis of Crohn's disease. Methods: This study was a cohort analysis of both clinical and biochemical parameters of patients with diagnosed inflammatory bowel disease compared with those in a control population. Antiglycan antibodies were determined using commercially available enzyme immunoassays. The setting was the outpatient unit of the gastroenterology department of a large, tertiary-care referral academic hospital. Participants were 214 consecutive patients, enrolled over a 5-month period, including 116 with Crohn's disease and 53 with ulcerative colitis, as well as 45 with other gastrointestinal diseases and 51 healthy controls. Results: Anti-Saccharomyces cerevisiae antibodies showed the best performance (54% sensitivity and 88%-95% specificity for Crohn's disease). Among patients with negative anti-Saccharomyces antibodies, 19 (34%) had high titers of at least another tested antiglycan antibody. Anti-Saccharomyces and anti-laminaribioside antibodies were associated with disease involving the small bowel and with penetrating or stricturing phenotype. Anti-laminaribioside was significantly higher in patients with a familial history of inflam-matory bowel disease. Conclusions: The new proposed serological markers are significantly associated with Crohn's disease, with low sensitivity but good specificity. About one third of anti-Saccharomyces-negative patients may be positive for at least 1 of those markers. Antiglycan antibodies appear to be associated with characteristic localization and phenotype of the disease.