The liver cell response to hepatitis C, a positive-strand RNA virus of the flaviviridiae, varies considerably from acute disease to chronic hepatitis, and from inapparent infection to cirrhosis. The cellular injury to the host depends on host—viral interactions (Table 1 ): in general, the more active the immune response, the greater the cellular injury. If viral infection leads to cell lysis, then the organism dies as is seen in fulminant hepatitis, a relatively rare event (<1% response seen after hepatotrophic viral infection and rare in HCV infection). If cellular dysfunction occurs, then clinical disease results. If viral replication occurs without cellular damage, then inapparent infection results. If the individual is exposed without attachment to the host, then no infection occurs Table 1? Host-Cell Response: Outcome of HCV Infection