CD4 and AIDS: Previous in vitro evidence indicated that statins were not efficient in inhibiting the infection of CD4+ T cells by X4 strains of HIV-1, in contrast to their capacity to hamper the infection by R5 strains [25]; these observations generated the hypothesis that the long-term administration of statins to HIV-1-infected patients could lead to the selection of X4 strains, contributing to accelerate the evolution of HIV infection to AIDS.