Decreased frequencies of virus-specific T helper type 1 cells during interferon alpha plus ribavirin treatment in HIV-hepatitis C virus co-infection.

Anti-hepatitis C virus (HCV) treatment combining IFN-alpha and ribavirin (IFN+R) has still poorly defined effects on immune responses. Frequencies of T helper (Th) type 1 cells specific for HCV, cytomegalovirus (CMV) and HIV were measured in chronically HCV-infected patients with or without HIV co-infection during IFN+R treatment. Although scarce, peripheral blood HCV-specific Th1 cells did not change significantly, while frequencies of HIV and CMV-specific Th1 cells decreased in co-infected patients independently of CD4 cell count changes. This suggests that IFN+R therapy might compromise virus-specific immune defenses in immunosuppressed patients.