SCOPE: Observational Study of the Consequences of the Protease Inhibitor Era

Inclusion Criteria: SCOPE is currently recruiting HIV-1 infected subjects with any of the following criteria: 1. Documented HIV viral load less than 2000 copies/ml WITHOUT taking antiretroviral therapy 2. Undetectable HIV viral load with CD4 T-cells consistently less than 350 for the last 12 months while taking a stable antiretroviral regimen. 3. Antiretroviral naive and planning to start an antiretroviral regimen - any CD4 or HIV viral load acceptable. 4. Long-term Non Progressors: HIV-positive at least 10 years, no antiretroviral therapy for the past 10 years or more, any viral load acceptable, CD4-T cell count always above 500. Exclusion Criteria: 1. Active opportunistic infection or systemic treatment for opportunistic infection within the last 4 months (oral candidiasis acceptable) 2. Active treatment for cancer 3. Active treatment for hepatitis C requiring interferon based therapy 4. Immunosuppressive therapy taken within the last 4 months