A cationic glycoprotein pattern in human serum and cerebrospinal fluid with pathological implications

Patterns of highly glycosylated proteins with mainly cationic isoelectric points, pH 6.5-9.5, were observed in serum and cerebrospinal fluid of patients with various disorders. Detection was performed after isoelectric focusing, using an immunoassay specific for digoxigenylated carbohydrate moieties of glycoconjugates. To our knowledge, these glycoproteins have not hitherto been described as regular serum proteins. The patterns were found among 7% of the patients studied (n = 400). Similar bands were not detectable in a reference group of 100 persons without clinical symptoms. The glycoprotein pattern was specific for each individual. The pathophysiological meaning of these glycoproteins as well as the basic biochemistry has not yet been evaluated. The glycoproteins, however, were shown to differ from immunoglobulin G, oligoclonal immunoglobulin G, paraprotein or from regular cationic serum protein. By comparison with standard glycoproteins a carbohydrate content of 30 +/- 10% was roughly suggested. The oligosaccharides contain probably sialic acid as evidenced by lectin binding. Although the diagnoses varied, 90% of the patients with this glycoprotein pattern had inflammatory processes.