Moreover, the increase in the rate of AST among HIV/HCV co-infected participants could also be linked to the increased replication of HCV-RNA activated by HIV infection; In fact, the interaction between HIV gp120 and CCR5/CXCR4 co-receptors on hepatocytes via TGF-β1 which is a key mediator in the process of liver fibrosis as it is one of the most profibrogenic cytokines [9]. The gene discussed is CXCR4; the disease is Hepatic fibrosis.