Prevalence of circulating immunecomplexes and variations of complement fractions in HBV, HDV and HCV infections: statistical analysis and clinical correlations.

Increased levels of circulating immunecomplexes (CIC) have been demonstrated in the serum of patients with HBV infection and HDV superinfection. This finding appears to be correlated to the disease's activity. In this report serum levels of two fractions of CIC (CIC-Clq and CIC-C3d) were evaluated by ELISA method in a sample of 110 subjects with hepatitis infection (HBV, HCV, HDV). Reference values were obtained in a group of 45 healthy subjects (blood donors). Both the CIC fractions were increased in the patients with HCV infection. The most significant increase for both CIC-C1q and CIC-C3d was found in the cirrhotic patients. The complement fractions C3c and C4 were determined in the serum of these patients to investigate a potential pathogenic role of such immunecomplexes. C3c and C4 fractions showed a significant decrease only in the cirrhotic patients, without correlation with the viral agent. Serum levels of C1q complement fraction were not significantly decreased, thus excluding an impaired synthesis of complement fractions. No significant correlation was found between CIC and C3c and C4 fractions in patients with increased levels of CIC, except a slightly significant correlation between reduction of C3c and increase of CIC-C1q. These data suggest a pathogenic action of immunecomplexes in the course of HCV, particularly in the cirrhotic stage.