Association of the novel serologic anti-glycan antibodies anti-laminarin and anti-chitin with complicated Crohn's disease behavior.

Background: We tested a panel of novel serological anti-glycan antibodies including the previously unpublished anti-laminarin IgA (Anti-L) and anti-chitin IgA (Anti-C) carbohydrate antibodies for the presence in Crohn's disease (CD) patients, diagnosis and differentiation of CD, association with complicated disease behavior, and marker stability over time.

Methods: The presence of Anti-L, Anti-C, anti-chitobioside IgA (ACCA), anti-laminaribioside IgG (ALCA), anti-mannobioside IgG (AMCA), and anti-Saccaromyces cervisiae IgG (gASCA) carbohydrate antibodies were tested in serum samples from 824 participants (363 CD, 130 ulcerative colitis [UC], 74 other gastrointestinal diseases, and 257 noninflammatory bowel/gastrointestinal disease controls) of the German IBD-network by enzyme-linked immunosorbent assay (ELISA; Glycominds, Lod, Israel) and for perinuclear antineutrophil cytoplasmic antibody (pANCA) by immunofluorescence.

Results: In all, 77.4% of the CD patients were positive for at least 1 of the anti-glycan antibodies. gASCA or the combination of gASCA/pANCA remained most accurate for the diagnosis of CD, but the combined use of the antibodies improved differentiation of CD from UC. Several single markers as well as an increasing antibody response were independently linked to a severe disease phenotype, as shown for the occurrence of complications, CD-related surgery, early disease onset, and ileal disease location. This was observed for both quantitative and qualitative antibody responses. The antibody status remained stable over time in most IBD patients.

Conclusions: A panel of anti-glycan antibodies including the novel Anti-L and Anti-C may aid in differentiation of CD from UC, is associated with complicated CD behavior and IBD-related surgery, and is stable over time in a large patient cohort.