4. For HIV seropositive subjects, meeting one of the following criteria: (1) on stable highly active antiretroviral therapy (HAART) with a recent undetectable viral load (< 50 copies/mL) ("HAART suppressed"), (2) antiretroviral untreated with an undetectable viral load (< 50 copies/mL) ("elite" controllers), or (3) antiretroviral untreated with a detectable viral load (> 1000 copies/mL) ("non-controllers")