EXAMINING HIV-1 PROVIRAL DNA IN THE LIVER TISSUE OF UNTREATED PEOPLE WITH HIV-ASSOCIATED DEMENTIA

Human immunodeficiency virus type 1 (HIV-1) typically uses CCR5 as a coreceptor and requires a high surface density of its CD4 receptor to target replication in CD4+ T cells. HIV-1 can evolve to enter cells with low surface density CD4. This phenotype is frequently observed in the central nervous system (CNS) of people with HIV-associated dementia (HAD). The putative CNS target cells are macrophage and microglia, both with low CD4. The liver also contains abundant macrophages. I hypothesized that macrophage-tropic variants can travel from the CNS and replicate in liver macrophage. To test this, I generated viral env genes from blood, cerebrospinal fluid (CSF), and liver from four people with HAD and assessed the entry phenotype to determine if any used low CD4. I found little evidence of macrophage-tropic HIV-1 in the liver but the presence of viral recombinants suggests the virus can travel to the liver and transiently replicate.Master of Scienc

Compartmentalization, Viral Evolution, and Viral Latency of HIV in the CNS

Human immunodeficiency virus type 1 (HIV-1) infection occurs throughout the body, and can have dramatic physical effects, such as neurocognitive impairment in the central nervous system (CNS). Furthermore, examining the virus that resides in the CNS is challenging due to its location and can only be done using samples collected either at autopsy, indirectly form the cerebral spinal fluid (CSF), or through the use of animal models. The unique milieu of the CNS fosters viral compartmentalization as well as evolution of viral sequences, allowing for new cell types, such as macrophages and microglia, to be infected. Treatment must also cross the blood brain barrier adding additional obstacles in eliminating viral populations in the CNS. These long-lived infected cell types and treatment barriers may affect functional cure strategies in people on highly active antiretroviral therapy (HAART)

HIV-1 Populations in Semen Arise through Multiple Mechanisms

HIV-1 is present in anatomical compartments and bodily fluids. Most transmissions occur through sexual acts, making virus in semen the proximal source in male donors. We find three distinct relationships in comparing viral RNA populations between blood and semen in men with chronic HIV-1 infection, and we propose that the viral populations in semen arise by multiple mechanisms including: direct import of virus, oligoclonal amplification within the seminal tract, or compartmentalization. In addition, we find significant enrichment of six out of nineteen cytokines and chemokines in semen of both HIV-infected and uninfected men, and another seven further enriched in infected individuals. The enrichment of cytokines involved in innate immunity in the seminal tract, complemented with chemokines in infected men, creates an environment conducive to T cell activation and viral replication. These studies define different relationships between virus in blood and semen that can significantly alter the composition of the viral population at the source that is most proximal to the transmitted virus

HIV-1 Populations in Semen Arise through Multiple Mechanisms

HIV-1 is present in anatomical compartments and bodily fluids. Most transmissions occur through sexual acts, making virus in semen the proximal source in male donors. We find three distinct relationships in comparing viral RNA populations between blood and semen in men with chronic HIV-1 infection, and we propose that the viral populations in semen arise by multiple mechanisms including: direct import of virus, oligoclonal amplification within the seminal tract, or compartmentalization. In addition, we find significant enrichment of six out of nineteen cytokines and chemokines in semen of both HIV-infected and uninfected men, and another seven further enriched in infected individuals. The enrichment of cytokines involved in innate immunity in the seminal tract, complemented with chemokines in infected men, creates an environment conducive to T cell activation and viral replication. These studies define different relationships between virus in blood and semen that can significantly alter the composition of the viral population at the source that is most proximal to the transmitted virus

HIV-1 detection in the olfactory mucosa of HIV-1 infected participants

OBJECTIVE: Human Immunodeficiency virus (HIV) infection chronically affects the central nervous system (CNS). Olfactory mucosa (OM) is a unique site in the respiratory tract that is directly connected to the CNS, thus we wanted to evaluate OM as a surrogate of CNS sampling. DESIGN: We conducted a preliminary study examining HIV populations and susceptible cells in the OM. METHODS: OM was sampled by minimally invasive brushing. CSF analyses were performed as per routine clinical procedures. OMP, CD4, CD8 and TAT expressions were assessed by immunohistochemistry. Plasma, CSF and OM HIV-RNA were quantified using the CAP/CTM assay, while HIV proviral DNA was evaluated on PBMC and OM. HIV-1 env deep sequencing was performed for phylogenetic analysis. RESULTS: 88.2% of ART naive participants (15/17) and 21.4% of ART treated participants (6/28) had detectable HIV-RNA in samples from their OM; CSF escape was more common in patients with OM escape (50% vs. 7.9%, p\u200a=\u200a0.010). OM samples contained few cells positive for CD4, CD8 or HIV-DNA and no HIV TAT-positive cells, indicating that this approach efficiently samples virions in the OM, but not HIV-infected cells. Yet, using a deep sequencing approach to phylogenetically compare partial HIV env genes in five untreated participants, we identified distinct viral lineages in the OM. CONCLUSIONS: The results of this study suggest that nasal brushing is a safe and useful technique for sampling the olfactory mucosa. HIV RNA was detected in most na\uefve and in some treated patients warranting larger longitudinal studies

Rebound HIV-1 in cerebrospinal fluid after antiviral therapy interruption is mainly clonally amplified R5 T cell-tropic virus

HIV-1 persists as a latent reservoir in people receiving suppressive antiretroviral therapy (ART). When ART is interrupted (treatment interruption/TI), rebound virus re-initiates systemic infection in the lymphoid system. During TI, HIV-1 is also detected in cerebrospinal fluid (CSF), although the source of this rebound virus is unknown. To investigate whether there is a distinct HIV-1 reservoir in the central nervous system (CNS), we compared rebound virus after TI in the blood and CSF of 11 participants. Peak rebound CSF viral loads vary and we show that high viral loads and the appearance of clonally amplified viral lineages in the CSF are correlated with the transient influx of white blood cells. We found no evidence of rebound macrophage-tropic virus in the CSF, even in one individual who had macrophage-tropic HIV-1 in the CSF pre-therapy. We propose a model in which R5 T cell-tropic virus is released from infected T cells that enter the CNS from the blood (or are resident in the CNS during therapy), with clonal amplification of infected T cells and virus replication occurring in the CNS during TI

Rebound HIV-1 in cerebrospinal fluid after antiviral therapy interruption is mainly clonally amplified R5 T cell-tropic virus

HIV-1 persists as a latent reservoir in people receiving suppressive antiretroviral therapy (ART). When ART is interrupted (treatment interruption/TI), rebound virus re-initiates systemic infection in the lymphoid system. During TI, HIV-1 is also detected in cerebrospinal fluid (CSF), although the source of this rebound virus is unknown. To investigate whether there is a distinct HIV-1 reservoir in the central nervous system (CNS), we compared rebound virus after TI in the blood and CSF of 11 participants. Peak rebound CSF viral loads vary and we show that high viral loads and the appearance of clonally amplified viral lineages in the CSF are correlated with the transient influx of white blood cells. We found no evidence of rebound macrophage-tropic virus in the CSF, even in one individual who had macrophage-tropic HIV-1 in the CSF pre-therapy. We propose a model in which R5 T cell-tropic virus is released from infected T cells that enter the CNS from the blood (or are resident in the CNS during therapy), with clonal amplification of infected T cells and virus replication occurring in the CNS during TI

Predicting Efavirenz Concentrations in the Brain Tissue of HIV‐Infected Individuals and Exploring their Relationship to Neurocognitive Impairment

Sparse data exist on the penetration of antiretrovirals into brain tissue. In this work, we present a framework to use efavirenz (EFV) pharmacokinetic (PK) data in plasma, cerebrospinal fluid (CSF), and brain tissue of eight rhesus macaques to predict brain tissue concentrations in HIV‐infected individuals. We then perform exposure‐response analysis with the model‐predicted EFV area under the concentration‐time curve (AUC) and neurocognitive scores collected from a group of 24 HIV‐infected participants. Adult rhesus macaques were dosed daily with 200 mg EFV (as part of a four‐drug regimen) for 10 days. Plasma was collected at 8 time points over 10 days and at necropsy, whereas CSF and brain tissue were collected at necropsy. In the clinical study, data were obtained from one paired plasma and CSF sample of participants prescribed EFV, and neuropsychological test evaluations were administered across 15 domains. PK modeling was performed using ADAPT version 5.0 Biomedical Simulation Resource, Los Angeles, CA) with the iterative two‐stage estimation method. An eight‐compartment model best described EFV distribution across the plasma, CSF, and brain tissue of rhesus macaques and humans. Model‐predicted median brain tissue concentrations in humans were 31 and 8,000 ng/mL, respectively. Model‐predicted brain tissue AUC was highly correlated with plasma AUC (γ = 0.99, P  0.05). This analysis provides an approach to estimate PK the brain tissue in order to perform PK/pharmacodynamic analyses at the target site