Sugar printing rheumatic diseases - A potential method for disease differentiation using immunoglobulin G oligosaccharides

Objective. To look for oligosaccharide structural variants of IgG that may be unique to specific rheumatic diseases. Methods. Using normal-phase high-performance liquid chromatography technolo gy, a comparison was made of the oligosaccharide pools released from serum IgG from patients with systemic lupus erythematosus (SLE) (n = 10), ankylos ing spondylitis (AS) (n = 10), primary Sjogren's syndrome (n = 6), juvenile chronic arthritis (JCA) (n = 13), psoriatic arthritis (n = 9), rheumatoid arthritis (RA) (n = 5), and healthy control individuals (n = 19). Results. The oligosaccharide pools were resolved into 13 peaks and the rela tive proportions of the peaks in each disease group was significantly diffe rent from that in healthy controls (P < 0.0001-0.05). A characteristic seru m IgG oligosaccharide profile, or sugar print, for each of the rheumatic di seases was found. The sugar prints exhibited a range of glycosylation patte rns whereby all RA (P < 0.0001) and JCA (P < 0.006) patients had predominan tly agalactosyl structures, while SLE (P < 0.03-0.0001) and AS (P < 0.025-0 .0001) patients had predominantly digalactosyl structures. Conclusion. The data suggest that each disease is associated with a specifi c mechanism that gives rise to alterations in the normal glycosylation patt ern of IgG. Sugar printing of IgG is therefore a potential means for the di fferentiation of rheumatic diseases and may provide insight into disease pa thogenesis.