Study of Anti-glycan Antibodies Stability in Saint-Etienne IBD Cohort

Prognostic factors in Inflammatory Bowel Diseases (IBD) are currently mainly based on clinical factors (disease extension, perianal involvement, need for surgery, use of immunomodulators…). All of immunological markers (or serological) of IBD have a diagnostic role in indeterminate colitis (ulcerative colitis vs crohn's disease) but they never have been considered as predictors of IBD course in adults. Among the most used, anti-neutrophil cytoplasm antibodies (ANCA) and Anti-Saccaromyces cerevisiae antibodies (ASCA) allow the distinction between ulcerative colitis (ANCA+/ASCA-) and Crohn's disease (ANCA-/ASCA+), and their combined use has a sensitivity and a specificity of about 85%. However, 10 other antibodies have been identified and recently evaluated individually in IBD and especially in pediatric Crohn's disease: anti-ompC, anti-I2, anti-flagellins, anti-glycan (anti-laminaribioside carbohydrate antibodies (ALCA), anti-mannobioside carbohydrate antibodies (AMCA), anti-chitobioside carbohydrate antibody (ACCA), anti-chitin and anti-laminarin), anti-goblet cells and anti-C.albicans specific mannans antibodies. These complementary tests improve the reliability of the diagnosis. In a previous cross-sectional work on a cohort of 195 IBD patients, the investigator showed a prognostic role of some of anti-glycan Abs and especially a correlation with a pejorative form of the disease both in Crohn's disease than in Ulcerative Colitis (UC) and a prediction of corticodependency in IBD.

There is few data on the stability of these antibodies, most of the studies are cross-sectional. There are conflicting results among scarce longitudinal data. One study reported a negativation of anti-glycan antibodies in some cases but not of ASCA or ANCA. On the cohort of 195 patients included in the first study, the investigator would like to assess at 3 years the immunological profiles of these patients and thus to compare them. In case of modification of the serological status for some antibodies, the search for associated factors (clinical, biological or therapeutic) will be performed. In case of sero-negativation of anti-glycan antibodies, this could be linked with a decrease or a normalization of the increased intestinal permeability in IBD. Indeed, in this subgroup of patients, we will test this hypothesis by analyzing intestinal permeability in anti-glycan positive group on the 2 samples and in the group with a sero-negativation on the second sample.