Cohort A1: ART (Antiretroviral therapy) -treated HIV-infected individuals with lipodystrophy (n=35) Cohort A2: ART-treated HIV-infected individuals without lipodystrophy (n=18) Cohort A3: HIV-1 infected individuals naïve to ART (n=20) Cohort A4: HIV-1 seronegative individuals who are at a high risk for infection (n=20)