Modifications of concanavalin A patterns of alpha 1-acid glycoprotein and alpha 2-HS glycoprotein in alcoholic liver disease.

In order to test whether abnormalities in hepatocytes affect the glycoprotein carbohydrate moiety, crossed immunoaffinoelectrophoresis (CIAE) with Concanavalin A (Con A) was used to study serum alpha 1-acid glycoprotein (alpha 1-AGP) and alpha 2-HS glycoprotein (alpha 2-HS) obtained from alcoholic patients with biopsy-proven liver disease. Cirrhotic patients, placed in groups C1, C2 or C3, according to Pugh's classification, were compared to healthy donors (N) and to steatosic non-cirrhotic patients (S). Con A CIAE patterns revealed in group N three subpopulations for alpha 2-HS and four for alpha 1-AGP. Two main results emerged from this study: (1) in the alcoholic groups, the proportions of Con A-unreactive subpopulations of both glycoproteins increased. Moreover, group N could be separated from group S and group S from all the cirrhotic groups. (2) There was a good correlation between the relative amounts in Con A-unreactive subpopulations of alpha 1-AGP and alpha 2-HS. The increases observed in Con A-unreactive subpopulations are probably a general phenomenon related to alterations in glycosylation processing during liver cell damage.

Evaluation of the degree of desialylation of serum C1-inactivator and haemopexin.

The calibration curves for evaluating the degree of desialylation of C1-inactivator (sialic acid content 12.5%) and haemopexin (sialic acid content 4%) have been plotted. No desialylation of either glycoprotein occurs in normal subjects. In the patients (liver damage) studied, C1-inactivator is often desialylated, whereas haemopexin is not. In a previous report, we had shown that alpha1-acid glycoprotein is more often desialylated than alpha1-antitrypsin. Thus, it appears that the degree of desialylation of the sialic acid-rich glycoproteins is a more sensitive index of the severity of hepatic injury than that of the sialic acid-poor glycoproteins. This could be due to a defect in the sialylation process during synthesis.