Upon initial entry into blood, HIV-1 is faced with three major options: (a) directly infect a CD4(+) target cell; (b) remain as a circulating free virion while it searches for a target cell; or (c) temporarily bind to the surface of a CD4(−) cell, such as a circulating dendritic cell, as a depot for infection by transfer of the virus (infection in trans) to a CD4(+) cell [1]. The gene discussed is CD4; the disease is infection.