Detection of immunoglobulin G glycosylation changes in patients with rheumatoid arthritis by means of isoelectric focusing and lectin-affinoblotting.

Patients with rheumatoid arthritis have a reduced prevalence of immunoglobulin G (IgG) oligosaccharide chains terminating in galactose, thus exposing N-acetylglucosamine. We analyzed IgG glycosylation in patients with rheumatoid arthritis, patients with early synovitis, and in controls by means of isoelectric focusing and lectin-affinoblotting. The ratio of N-terminal N-acetylglucosamine and galactose was determined using specific biotin-labeled lectins. The IgG glycosylation state may well be of clinical value in the differential diagnosis of patients presenting with early synovitis.