Changes of serum-associated fucosylated glycoproteins and changes in glycosylation of IgA in human cirrhosis

Many modifications in N-glycosylation have been demonstrated in hepatic cirrhosis. These modifications correspond to an increase of a bisecting core alpha (1,6)-fucosylated biantermary glycan, an increase in core fucosylation, and the presence of an important population of neutral oligosaccharides in human serum of cirrhotic patients. In this study, a glycoproteomic approach which consists of lectin affinity chromatography, MALDI-TOF MS for the characterization of N-glycans released from glycoproteins, one- and 2-D PAGE, electrospray ionization quadrupole ion trap (ESI-QIT) MS was used to identify serum fucosylated glycoproteins related to cirrhosis. Employing this method, we have shown that IgA is one of the major proteins that is responsible of the glycosylation modifications observed in the serum N-glycome of cirrhotic patients. To our knowledge, this is the first time that aberrant N-glycosylation of IgA in cirrhosis is described.