To investigate the association between glycosylation and immune complex formation in various disease groups.
Immune complexes and IgG were isolated from serum and their carbohydrate content evaluated in a dot-blot assay using specifically binding lectins.
Significantly more N-acetylglucosamine was detected in complexes from patients with rheumatoid arthritis (RA) than in those from patients with systemic lupus erythematosus, Crohn's disease, or infectious endocarditis, or from normal controls (P < 0.001). The immune complex concentration in the circulation was strongly associated with N-acetylglucosamine levels (P < 0.001 by chi-square analysis).
The composition of immune complexes from RA patients is distinct in carbohydrate content from those found in other disease groups.