[Cystatin C: a biological role and impaired secretion in viral hepatitis c and hepatic cirrhosis].

Cystatin C is a non-glycated cationic protein with a molecular weight of 13.3 kD, which belongs to the superfamily of cystatins; its basic function is to inhibit and regulate the activity of cysteine proteinase. In apparently healthy individuals, the extracellular concentration of cystatin C is shown to be substantially higher in serum than in urine and bile. The increased serum concentration of cystatin C has been found in the development of chronic viral hepatitis C, and hepatic cirrhosis in particular, which reflects the development of an inflammatory process and, evidently, the higher secretion of cystatin C by stimulated macrophages.