Brief Report

Monocytes play a vital role in HIV-associated neurocognitive disorder (HAND), postulated to transport HIV into the brain and secrete pro-inflammatory cytokines. We analyzed cytokines released by cultured peripheral blood mononuclear cells enriched with the CD14 marker isolated from HIV-infected individuals with HAND and normal cognition (NC) in combination antiretroviral therapy naive and after 1 year on treatment. Interleukin-8 and monocyte chemoattractant protein-1 levels were higher in HAND compared with NC at baseline (P = 0.002 and P < 0.0001). These cytokines remained higher in HAND patients 1 year after combination antiretroviral therapy and were significant when NC patients who were initially HAND were excluded (P = 0.012 and P = 0.002). Both correlated with baseline CD14 peripheral blood mononuclear cell HIV DNA levels supporting the role of HIV DNA reservoir size and monocyte cytokines in HAND persistence

HIV DNA in CD14+ reservoirs is associated with regional brain atrophy in patients naive to combination antiretroviral therapy.

ObjectiveTo examine associations between regional brain volumes and HIV DNA in peripheral CD14 cells (monocytes) among HIV-infected individuals naive to combination antiretroviral therapy (cART).DesignA prospective study of HIV-infected Thai individuals who met Thai national criteria for cART initiation. Enrolment was stratified by HIV DNA in a blinded fashion.MethodsCD14 cells were isolated from peripheral mononuclear cells to high purity (median 91.4% monocytes by flow cytometry), and HIV DNA was quantified by multiplex real-time PCR. Baseline regional brain volumes obtained by T1-weighted 1.5-Tesla MRI were compared between HIV DNA groups using analysis of covariance (ANCOVA).ResultsWe studied 60 individuals with mean (SD) age of 34.7 (7.0) years, CD4 T-lymphocyte count of 232 (137) cells/μl and log10 plasma HIV RNA of 4.8 (0.73). Median (interquartile range, IQR) HIV DNA copy number per 10 CD14 cells was 54 (102). Using our previously determined optimal cut-point of 45 copies/10 cells for this cohort, a threshold value above which CD14 HIV DNA identified HIV-associated neurocognitive disorders (HANDs), we found that CD14 HIV DNA  ≥ 45 copies/10 cells was associated with reduced volumes of the nucleus accumbens (P=0.021), brainstem (P=0.033) and total gray matter (P=0.045) independently of age, CD4 cell count and intracranial volume.ConclusionHIV DNA burden in CD14 monocytes is directly linked to brain volumetric loss. Our findings implicate peripheral viral reservoirs in HIV-associated brain atrophy and support their involvement in the neuropathogenesis of HAND, underscoring the need for therapies that target these cells

Elevated cerebrospinal fluid Galectin-9 is associated with central nervous system immune activation and poor cognitive performance in older HIV-infected individuals

We previously reported that galectin-9 (Gal-9), a soluble lectin with immunomodulatory properties, is elevated in plasma during HIV infection and induces HIV transcription. The link between Gal-9 and compromised neuronal function is becoming increasingly evident; however, the association with neuroHIV remains unknown. We measured Gal-9 levels by ELISA in cerebrospinal fluid (CSF) and plasma of 70 HIV-infected (HIV+) adults stratified by age (older > 40 years and younger < 40 years) either ART suppressed or with detectable CSF HIV RNA, including a subgroup with cognitive assessments, and 18 HIV uninfected (HIV-) controls. Gal-9 tissue expression was compared in necropsy brain specimens from HIV- and HIV+ donors using gene datasets and immunohistochemistry. Among older HIV+ adults, CSF Gal-9 was elevated in the ART suppressed and CSF viremic groups compared to controls, whereas in the younger group, Gal-9 levels were elevated only in the CSF viremic group (p < 0.05). CSF Gal-9 positively correlated with age in all groups (p < 0.05). CSF Gal-9 tracked with CSF HIV RNA irrespective of age (β = 0.33; p < 0.05). Higher CSF Gal-9 in the older viremic HIV+ group correlated with worse neuropsychological test performance scores independently of age and CSF HIV RNA (p < 0.05). Furthermore, CSF Gal-9 directly correlated with myeloid activation (CSF-soluble CD163 and neopterin) in both HIV+ older groups (p < 0.05). Among HIV+ necropsy specimens, Gal-9 expression was increased in select brain regions compared to controls (p < 0.05). Gal-9 may serve as a novel neuroimmuno-modulatory protein that is involved in driving cognitive deficits in those aging with HIV and may be valuable in tracking cognitive abnormalities

HIV DNA reservoir increases risk for cognitive disorders in cART-naïve patients.

ObjectivesCognitive impairment remains frequent in HIV, despite combination antiretroviral therapy (cART). Leading theories implicate peripheral monocyte HIV DNA reservoirs as a mechanism for spread of the virus to the brain. These reservoirs remain present despite cART. The objective of this study was to determine if the level of HIV DNA in CD14(+) enriched monocytes predicted cognitive impairment and brain injury.MethodsWe enrolled 61 cART-naïve HIV-infected Thais in a prospective study and measured HIV DNA in CD14(+) enriched monocyte samples in a blinded fashion. We determined HAND diagnoses by consensus panel and all participants underwent magnetic resonance spectroscopy (MRS) to measure markers of brain injury. Immune activation was measured via cytokines in cerebrospinal fluid (CSF).ResultsThe mean (SD) age was 35 (6.9) years, CD4 T-lymphocyte count was 236 (139) and log10 plasma HIV RNA was 4.8 (0.73). Twenty-eight of 61 met HAND criteria. The log10 CD14(+) HIV DNA was associated with HAND in unadjusted and adjusted models (p = 0.001). There was a 14.5 increased odds ratio for HAND per 1 log-value of HIV DNA (10-fold increase in copy number). Plasma CD14(+) HIV DNA was associated with plasma and CSF neopterin (p = 0.023) and with MRS markers of neuronal injury (lower N-acetyl aspartate) and glial dysfunction (higher myoinositol) in multiple brain regions.InterpretationReservoir burden of HIV DNA in monocyte-enriched (CD14(+)) peripheral blood cells increases risk for HAND in treatment-naïve HIV+ subjects and is directly associated with CSF immune activation and both brain injury and glial dysfunction by MRS

HIV DNA reservoir increases risk for cognitive disorders in cART-naïve patients.

ObjectivesCognitive impairment remains frequent in HIV, despite combination antiretroviral therapy (cART). Leading theories implicate peripheral monocyte HIV DNA reservoirs as a mechanism for spread of the virus to the brain. These reservoirs remain present despite cART. The objective of this study was to determine if the level of HIV DNA in CD14(+) enriched monocytes predicted cognitive impairment and brain injury.MethodsWe enrolled 61 cART-naïve HIV-infected Thais in a prospective study and measured HIV DNA in CD14(+) enriched monocyte samples in a blinded fashion. We determined HAND diagnoses by consensus panel and all participants underwent magnetic resonance spectroscopy (MRS) to measure markers of brain injury. Immune activation was measured via cytokines in cerebrospinal fluid (CSF).ResultsThe mean (SD) age was 35 (6.9) years, CD4 T-lymphocyte count was 236 (139) and log10 plasma HIV RNA was 4.8 (0.73). Twenty-eight of 61 met HAND criteria. The log10 CD14(+) HIV DNA was associated with HAND in unadjusted and adjusted models (p = 0.001). There was a 14.5 increased odds ratio for HAND per 1 log-value of HIV DNA (10-fold increase in copy number). Plasma CD14(+) HIV DNA was associated with plasma and CSF neopterin (p = 0.023) and with MRS markers of neuronal injury (lower N-acetyl aspartate) and glial dysfunction (higher myoinositol) in multiple brain regions.InterpretationReservoir burden of HIV DNA in monocyte-enriched (CD14(+)) peripheral blood cells increases risk for HAND in treatment-naïve HIV+ subjects and is directly associated with CSF immune activation and both brain injury and glial dysfunction by MRS