Study SEARCH 026Assessment of the HIV CNS Reservoir, Neurological and Neuro-cognitive Effects, and Source of Rebound HIV in CNS in Subjects Participating in Study SEARCH 019

1. Clinical 1.1 Neurological exam: SEARCH employs the AIDS Clinical Trials Group (ACTG)-derived HIV macroneurological examination, a physician rated symptoms assessment of cognitive features typical of HIV-associated neurocognitive disorder (HAND) and peripheral neuropathy.

1.2 Neuropsychological assessments: SEARCH employs the HIV neurocognitive battery originally developed by Maj et al. designed to minimize cultural bias and tested in Bangkok. All subjects will have the full SEARCH battery as previously published, avoiding evaluations following invasive procedures. All testing is completed by certified nurse-psychometrists. Data are compared to a normative set of 500 HIV-negative, healthy, community dwelling Thais and stratified by age and educational attainment to define standardized z-scores. A psychiatric inventory mirrors that used for RV254 and has broad Thai validity data, and research nurses perform a functional assessment based on the Clinical Dementia Scale.

1.3 Lumbar puncture: Lumbar punctures are completed per standard clinical procedures using a Sprotte® (pencil-point) needle to minimize complications. Standard assessments of CSF and serum, protein and cell count are completed and approximately 20cc are collected and ultra-centrifuged. Cell pellets of CSF will be cryopreserved for future potential studies, with subject consent. Supernatants are divided into 0.5cc aliquots, and frozen to -80oC on the same day. CSF VDRL/RPR will be assessed at baseline for those with positive serology in SEARCH 019 and in follow-up if a new positive serology is reported in SEARCH 019 or if subject was CSF positive at baseline. Participant hospitalization for any research-related adverse events requiring admission will be arranged, if needed.

1.4 Neuro-imaging: Imaging studies will be performed at the Chulalongkorn University Hospital which is 100 meters from the TRCARC in Bangkok. These studies will take up to one hour maximum MRI scanner time for each subject and may include brain MRI, MRS, DTI and resting state functional MRI (fMRI). MRI and MRS are non-invasive methods to detect brain pathology (MRI) and to determine the in-vivo concentration of brain metabolites (MRS). DTI is a sensitive non-invasive magnetic resonance technique to analyze the three-dimensional diffusion of water within brain tissue. The diffusion of water within the brain is highly dependent on the underlying micro-architecture of the surrounding tissue, which is affected by both normal physiological processes (such as aging) as well as local neuropathological disease processes, such as those seen with HIV infection. Resting state functional MRI (fMRI) reveals patterns of activation of brain networks and is a sensitive measure of brain function prior to structural and anatomical changes detected by other methods. Gadolinium will not be used for research purposes. 2. Laboratory (all pertaining to CSF)

2.1 Measurement of soluble markers: Commercial ELISA kits (Human Quantikine ELISA kits; R&D Systems, Inc.) and Millipore Luminex assays will be used following manufacturer's instructions at the Yale Immune Monitoring Core Laboratory. Soluble biomarkers associated with immune activation and neurocognitive impairment will be measured, including CSF neopterin, MCP-1, sCD14, IL-6, sCD163, and IP-10.