ERVW-1 and coinfection: In HIV-HCV co-infection, the env gp120 of HIV was supposed to interact with HCV E2 in triggering the apoptosis mechanisms [42] to modulate the biology of human hepatic stellate cells which play a key role in the fibrosis pathogenesis [43], and to enhance the replication of HCV through the engagement of extracellular coreceptors on hepatocytes [44].