In vivo down regulation of HIV replication after hepatitis C superinfection

There are increasing molecular and clinical evidences that the effects of h uman immunodeficiency virus (HIV) infection can be modified by coinfection with other viruses. The objective was to investigate the viral interaction between HIV and hepatitis C virus (HCV) after HCV superinfection. A 16 year -old pregnant woman was evaluated because of icteric acute hepatitis. Admis sion laboratory tests showed the following results: ALT 877 IU/L; AST 1822 IU/L; bilirubin 6.79 mg/dl. Diagnosis of acute HCV was based on detection o f serum HCV RNA by PCR and anti-HCV seroconversion. ELISA for anti HIV test ing was positive and confirmed by western blot. Serum markers for other vir uses were negative. The patient was followed during 19 months; serum sample s were taken monthly during this period for detection of plasma HIV and HCV RNA. Levels of plasma HIV-RNA were positive in all samples tested before a nd after the onset of acute hepatitis C. Six months later and a for two mon th period, and 13 months later for a period of one month HIV viremia was un detectable; then HIV-RNA in plasma was detectable again. In conclusion, HCV superinfection may have temporarily interfered with HIV replication in our patient. The following observations support our hypothesis: it has been de monstrated that HIV-1 replication is suppressed by HCV core protein which h as transcriptional regulation properties of several viral and cellular prom oters. Clinical implications of this event are not generally known and the interaction between these two viruses in dual infections is worth consideri ng.