A retrospective study of hepatitis C virus carriers in a local endemic town in Japan. A possible presence of asymptomatic carrier.

Chronic hepatitis, cirrhosis, and hepatocellular carcinoma are the accepted sequelae of chronic hepatitis C virus (HCV) infection. However, the real natural history of HCV infection is not still well understood. To approach this problem, we investigated 91 individuals positive for antibodies against HCV (anti-HCV), who have received annual liver function examination in a local town known to have had high carrier rates of hepatitis B virus (HBV) and HCV. Among the 91 anti-HCV-positive individuals, 63 had undertaken the annual examination more than five times in the past 14 years. We analyzed retrospectively the past liver function test results of these 63 subjects and evaluated their present virological status by determining HCV genotypes and estimating quantity of HCV RNA in the sera. Among the 63 subjects, 50 (79.4%) had HCV RNA in the serum and 40 (80%) of the 50 subjects with HCV RNA had abnormal alanine aminotransferase or aspartate aminotransferase level more than once in their records. However, the other 10 (20%) had no abnormal levels during the period examined. Six of 50 (12%) had ultrasonographic findings suggestive of cirrhosis. Thus, HCV-infected individuals in this area did not seem to have progressive liver diseases. Considering the advanced ages of the individuals examined (mean 64 years old), we may have observed a stage in the natural history of HCV infection in which viremia persists in most individuals and the tendency to progress to serious chronic liver disease is mild.