Cerebrospinal fluid (CSF) markers of immune activation, chronic monocyte activation, cytomegalovirus/Epstein-Barr virus (CMV/EBV) infection/reactivation, and neuronal injury will be collected. In addition, HIV viral load and genotype, genetic susceptibility factors and CNS penetration-effectiveness score (CPE) and CSF levels of antiretroviral drugs will be assessed. A repository of cryopreserved biological samples will be developed and used for validation of candidate biomarkers in future studies. Collection and analysis of these data will not only enhance understanding of the CNS as a potential HIV reservoir in virally-controlled individuals but will further define the association among cortical thickness, biomarkers and neurocognitive function in an aging HIV-infected population.