The significance of anti-hepatitis C virus antibodies measured in chronic liver disease.

The frequency of hepatitic C virus (HCV) antibodies was determined in two different laboratories in stored sera from 128 consecutive patients with chronic liver disease and from 41 healthy blood donors. Repeated measurements were performed in most patients. At the first determination the frequency of HCV antibodies was 7% in primary sclerosing cholangitis, 42% in primary biliary cirrhosis, 40% in autoimmune chronic active hepatitis, and 27% in alcoholic liver disease. The reproducibility of the determinations was rather poor, with a within-assay variation of 9.9%, whereas the between-assay variation was 34% and 47% in the two laboratories. There was a significant difference in the results obtained in the controls, depending on the handling of the sera. Freezing and thawing and, possibly, protracted storing of sera had a major impact on the assay and may have invalidated the results obtained in many studies. A significant association between IgG levels and titers of HCV antibodies was found in the total group of patients (p less than 0.005), in autoimmune chronic active hepatitis (p less than 0.005), and in primary biliary cirrhosis (p less than 0.01). It may be questioned whether the assay really is specific for anti-HCV antibodies in these patients. Whether HCV has anything to do with the etiology and pathogenesis of chronic liver disease apart from NANB-hepatitis is still undetermined.