AIDS: a role for host genes.

Suspicion that human genes affect the natural history of AIDS has been confirmed by discoveries of three such genes, one of which confers near-total immunity in about 1% of Caucasians. The findings suggest a novel therapeutic target: not HIV but the host's cooperation with it. They also herald an era in which genomes are seen as having been shaped by the evolutionary pressures of infection, and may thus hold evolution-tested therapies.