Immunoglobulin G galactosylation deficiency determined by isoelectric focusing and lectin affinoblotting in differential diagnosis of rheumatoid arthritis.

IgG galactosylation deficiency in patients with rheumatoid arthritis (RA) can be detected by isoelectric focusing (IEF)/lectin affinoblotting. We analyzed IgG glycosylation in patients with early arthritis (n = 50) and healthy controls in order to determine the clinical value of this parameter in differential diagnosis of RA. A significant correlation between the IgG galactosylation defect at disease onset and the diagnosis of RA during the follow-up was observed. Involvement of other clinical parameters (erythrocyte sedimentation rate, C-reactive protein, rheumatoid factor) did not improve the predictive value of IgG galactosylation changes.