There are several lines of evidence demonstrating that the liver efficiently clears many foreign pathogens, including RNA viruses. It is shown that liver is a major organ for clearing Simian Immunodeficiency Virus in rhesus monkeys [25] . There is also evidence for the detection of HIV RNA in the liver of HIV infected individuals [26] . These findings support the identification of HIV-specific T-cells in the liver. In HCV/HIV co-infection, it is possible that intra-hepatic HCV-specific CD4 + T-cells become infected with HIV and recruit HIV-specific immune responses to this site. Evidence for these potential mechanisms will need further analysis on liver biopsies of co-infected individuals.