The results of this study conducted in a large, and well-characterized natural history cohort of HIV-infected individuals indicate that in addition to the traditional markers of vulnerability (baseline CD4+ T cell count, viral load and rate of CD4+ T cell decline), the inclusion of a measure of genetic risk might offer an adjunctive, and complementary risk-stratification tool that may provide an improved method for identifying persons at high risk for future AIDS related events. The gene discussed is CD4; the disease is AIDS.