CHANGES IN GLYCOSYLATION OF IMMUNOGLOBULINS IN PRIMARY SJOGRENS-SYNDROME

Serum IgG and IgA are glycoprotein and significant glycoform abnormali ties have been established in primary Sjogren's syndrome, The proporti on of asialylated IgG is abnormally high in the patients, whereas IgA1 and IgA2 appear to be over-sialylated. This peculiarity might explain the defective binding of IgA to asialoglycoreceptors. Furthermore, th e activity of alpha 2,6 sialyl transferase is higher in the IgA-produc ing B cells from the patients than in the controls, whereas the alpha 2,3 sialyl transferase operates in the former cells but not in the lat ter, The mechanism of this enzyme dysregulation warrants elucidation.