Protection or damage: a dual role for the virus-specific cytotoxic T lymphocyte response in hepatitis B and C infection?

During infection with hepatitis B or C viruses, cytotoxic T lymphocytes (CT Ls) have been implicated as both the mediators of protection and the princi pal effecters of liver pathology. Recent studies have allowed an investigat ion of the relationship between virus-specific CTL responses, liver damage and viral replication. In the presence of an efficient virus-specific CTL r esponse, a scenario is emerging where inhibition of viral replication can b e independent of liver pathology. We discuss the possibility that an inadeq uate CTL response - unable to control viral replication - may contribute to liver pathology not only directly but also via the recruitment of non-viru s-specific T cells.