Anti-glycan antibodies as biomarkers for diagnosis and prognosis.

Glycans (sugars or carbohydrates) are predominant surface components of cells such as erythrocytes, immune cells and microorganisms. As such, they give rise to high levels of anti-glycan antibodies of all classes. Antibodies to certain defined mono, di and oligosaccharides that are common in bacterial, fungal and parasite cells exist in human sera and can be profiled using glycan arrays. The use of glycan arrays for systematic screening of blood samples from multiple sclerosis (MS) and Crohn's disease (CD) patients in versus to blood samples from control groups, have lead to the discovery of a few anti glycan antibodies biomarkers enabling diagnosis and prognosis in MS and CD patients. Anti-Glc(alpha1,4)Glc(alpha) IgM antibodies were found to be specific for MS patients, enabling differentiation between MS patients and patients with other neurological diseases, with 54% sensitivity and 85% specificity. Anti-Glc(alpha1,4)Glc(alpha) IgM were found to be predictive for the conversion of patients in first acute neurological event to clinically defined MS. Anti-laminaribioside (ALCA), anti-mannobioside (AMCA) and anti-chitobioside (ACCA) antibodies were found to be specific for CD. The combined use of these antibodies enables improved diagnosis of CD versus ulcerative colitis and other gastrointestinal diseases, as well as stratification of CD patients with a more complicated disease and high risk for surgery. Anti-glycan antibodies profiling (AGAP) is a new and promising approach for development of biomarkers for diagnosis and prognosis.