Neuropsychological Impairment in Acute HIV and the Effect of Immediate Antiretroviral Therapy

Central Nervous System Effects of Early HIV Infection and Consequences of Antiretroviral Therapy Initiation during Acute HIV

HIV infection is a multi-organ disease that involves the central nervous system (CNS). While devastating CNS complications such as HIV-associated dementia and CNS opportunistic infection typically manifest years after HIV acquisition, HIV RNA is readily detected in the cerebrospinal fluid in untreated neuroasymptomatic people with HIV, highlighting that HIV neuroinvasion predates overt clinical manifestations. Over the past two decades, increased awareness of HIV infection within the at-risk population, coupled with the accessibility of nucleic acid testing and modern HIV immunoassays, has made the detection of acute and early HIV infection readily achievable. This review aims to summarize research findings on CNS involvement during acute and early HIV infection, as well as the outcomes following the immediate initiation of antiretroviral therapy during this early stage of infection. The knowledge gap in long-term neuroprotection through early ART within the first year of infection will be discussed.

Cognitive Phenotypes of HIV Defined Using a Novel Data-driven Approach

The current study applied data-driven methods to identify and explain novel cognitive phenotypes of HIV. Methods: 388 people with HIV (PWH) with an average age of 46 (15.8) and median plasma CD4+ T-cell count of 555 copies/mL (79% virally suppressed) underwent cognitive testing and 3T neuroimaging. Demographics, HIV disease variables, and health comorbidities were recorded within three months of cognitive testing/neuroimaging. Hierarchical clustering was employed to identify cognitive phenotypes followed by ensemble machine learning to delineate the features that determined membership in the cognitive phenotypes. Hierarchical clustering identified five cognitive phenotypes. Cluster 1 (n=97) was comprised of individuals with normative performance on all cognitive tests. The remaining clusters were defined by impairment on action fluency (Cluster 2; n=46); verbal learning/memory (Cluster 3; n=73); action fluency and verbal learning/memory (Cluster 4; n=56); and action fluency, verbal learning/memory, and tests of executive function (Cluster 5; n=114). HIV detectability was most common in Cluster 5. Machine learning revealed that polysubstance use, race, educational attainment, and volumes of the precuneus, cingulate, nucleus accumbens, and thalamus differentiated membership in the normal vs. impaired clusters. The determinants of persistent cognitive impairment among PWH receiving suppressive treatment are multifactorial nature. Viral replication after ART plays a role in the causal pathway, but psychosocial factors (race inequities, substance use) merit increased attention as critical determinants of cognitive impairment in the context of ART. Results underscore the need for comprehensive person-centered interventions that go beyond adherence to patient care to achieve optimal cognitive health among PWH.

Adaptation and construct validity evaluation of a tablet-based, short neuropsychological test battery for use with adolescents and young adults living with HIV in Thailand

OBJECTIVE

Deficits in neurocognitive functioning are common among adolescents and young adults (AYA) with perinatally acquired HIV (PHIV). Limitations of traditional neuropsychological tests hinder assessment of neurocognition in low- and middle-income countries where most AYA with PHIV reside. Computerized testing could make assessment of neurocognition more accessible in these countries. This study examined a culturally modified NeuroScreen, a tablet-based neurocognitive testing app, for use in Thailand. Construct validity was examined among Thai AYA (13-23 years) with and without PHIV.

METHOD

NeuroScreen underwent adaptation including language, content, and usability review by Thai psychologists, AYA, and clinical staff. One hundred Thai AYA (50 PHIV; 50 HIV-uninfected, matched controls) were administered the adapted NeuroScreen and a battery of traditional paper-and-pencil neuropsychological tests. Correlations, mean differences, and proportions with impaired performance were examined across NeuroScreen and the traditional tests.

RESULTS

The Thai version of NeuroScreen was deemed understandable and culturally appropriate. A large correlation (.82) between overall performance on the NeuroScreen and traditional batteries was observed. Small-to-large correlations were found between conceptually similar NeuroScreen and traditional tests of processing speed, working memory, motor speed, and executive functioning. Mean test performance differences between AYA with PHIV and controls were similar between test batteries. Both sets of tests identified similar rates of impaired participants.

CONCLUSIONS

Results provide support for the acceptability and construct validity of the Thai NeuroScreen tests to assess neurocognition in Thai AYA with PHIV. An easy-to-use tool to assess neurocognition can help Thai providers provide better care for AYA with PHIV. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Individual Differences in CD4/CD8 T-Cell Ratio Trajectories and Associated Risk Profiles Modeled From Acute HIV Infection

OBJECTIVE

We examined individual differences in CD4/CD8 T-cell ratio trajectories and associated risk profiles from acute HIV infection (AHI) through 144 weeks of antiretroviral therapy (ART) using a data-driven approach.

METHODS

A total of 483 AHI participants began ART during Fiebig I-V and completed follow-up evaluations for 144 weeks. CD4+, CD8+, and CD4/CD8 T-cell ratio trajectories were defined followed by analyses to identify associated risk variables.

RESULTS

Participants had a median viral load (VL) of 5.88 copies/ml and CD4/CD8 T-cell ratio of 0.71 at enrollment. After 144 weeks of ART, the median CD4/CD8 T-cell ratio was 1.3. Longitudinal models revealed five CD4/CD8 T-cell ratio subgroups: group 1 (3%) exhibited a ratio >1.0 at all visits; groups 2 (18%) and 3 (29%) exhibited inversion at enrollment, with normalization 4 and 12 weeks after ART, respectively; and groups 4 (31%) and 5 (18%) experienced CD4/CD8 T-cell ratio inversion due to slow CD4+ T-cell recovery (group 4) or high CD8+ T-cell count (group 5). Persistent inversion corresponded to ART onset after Fiebig II, higher VL, soluble CD27 and TIM-3, and lower eosinophil count. Individuals with slow CD4+ T-cell recovery exhibited higher VL, lower white blood cell count, lower basophil percent, and treatment with standard ART, as well as worse mental health and cognition, compared with individuals with high CD8+ T-cell count.

CONCLUSIONS

Early HIV disease dynamics predict unfavorable CD4/CD8 T-cell ratio outcomes after ART. CD4+ and CD8+ T-cell trajectories contribute to inversion risk and correspond to specific viral, immune, and psychological profiles during AHI. Adjunctive strategies to achieve immune normalization merit consideration.

HIV Disease Dynamics and Markers of Inflammation and CNS Injury During Primary HIV Infection and Their Relationship to Cognitive Performance

INTRODUCTION

Early systemic and central nervous system viral replication and inflammation may affect brain integrity in people with HIV, leading to chronic cognitive symptoms not fully reversed by antiretroviral therapy (ART). This study examined associations between cognitive performance and markers of CNS injury associated with acute HIV infection and ART.

METHODS

HIV-infected MSM and transgender women (average age: 27 years and education: 13 years) enrolled within 100 days from the estimated date of detectable infection (EDDI). A cognitive performance (NP) protocol was administered at enrollment (before ART initiation) and every 24 weeks until week 192. An overall index of cognitive performance (NPZ) was created using local normative data. Blood (n = 87) and cerebrospinal fluid (CSF; n = 29) biomarkers of inflammation and neuronal injury were examined before ART initiation. Regression analyses assessed relationships between time since EDDI, pre-ART biomarkers, and NPZ.

RESULTS

Adjusting for multiple comparisons, shorter time since EDDI was associated with higher pre-ART VL and multiple biomarkers in plasma and CSF. NPZ scores were within the normative range at baseline (NPZ = 0.52) and at each follow-up visit, with a modest increase through week 192. Plasma or CSF biomarkers were not correlated with NP scores at baseline or after ART.

CONCLUSIONS

Biomarkers of CNS inflammation, immune activation, and neuronal injury peak early and then decline during acute HIV infection, confirming and extending results of other studies. Neither plasma nor CSF biomarkers during acute infection corresponded to NP scores before or after sustained ART in this cohort with few psychosocial risk factors for cognitive impairment.

A Meta-Analytic Review of the Effect of Antiretroviral Therapy on Neurocognitive Outcomes in Adults Living with HIV-1 in Low-and Middle-Income Countries

HIV-associated neurocognitive impairment remains a challenge even in the era of antiretroviral therapy (ART). Over 90% of people living with HIV are in low- and middle-income countries. Hence, it is not surprising that such countries bear a considerable burden of comorbidities like HIV-associated neurocognitive impairment despite an overall increase in life expectancy. The literature suggests differences in patient characteristics, clinical profile, prevalent HIV subtypes, treatment choices, pharmacogenetics, and socioeconomic factors between low- and middle-income countries compared with high-income countries. Therefore, we aimed to evaluate the effect of ART on neurocognitive outcomes in low- and middle-income countries. A comprehensive search of five databases (PubMed, CINAHL, CENTRAL, PsychInfo, Google scholar) for studies published between 1996 to 2020 was performed to identify studies that reported neurocognitive outcomes in ART-treated and ART naïve HIV positive individuals. Two independent reviewers conducted study screening, data extraction, and evaluation of the risk of bias. Pooled effect size estimates (Hedges' g) and 95% CI were computed using random-effects models. Sensitivity analysis, subgroup analysis, meta-regression, and evaluation of publication bias were also conducted. Forty studies (24 cross-sectional, 13 longitudinal studies, and two randomized controlled trials) contributed to a series of meta-analyses. We found significant small to moderate effects of antiretroviral therapy for global cognition (Hedges' g observed = 0.30; 95% CI: 0.15, 0.44; k = 25; p = 0.0003; I² = 92.1%; tau = 0.32; Q = 305.1), executive function (Hedges' g = 0.24, 95%CI: 0.02,0.46; p-0.04; k = 8; I² = 37.5%; tau = 0.23; Q = 11.2), and speed of information processing (Hedges' g = 0.25, 95% CI: 0.05, 0.45; k = 9; p = 0.02; I² = 86.4%; tau = 0.21; Q = 58.9). We found no significant ART effect on attention-working memory, learning and memory, motor function, and verbal fluency. No significant effect was seen with the duration of therapy, efavirenz use, and Central Penetrating Effectiveness (CPE) of antiretroviral therapy. Subgroup analyses identified study design (between-group and within-group; cross-sectional and longitudinal) and normative scores as significant sources of heterogeneity. Meta-regression analysis indicated that nadir CD4 modified the magnitude of ART's effect on cognitive outcomes. Age, gender, and country income-group were not significant moderators. Our findings provide systematic evidence that antiretroviral therapy improves neurocognitive outcomes in the domains of global cognition, executive function and speed of information processing, of people living with HIV in low- and middle-income countries, especially those with advanced immunosuppression. However, these findings are not definitive as they are limited by the probability of publication bias, high heterogeneity, and exclusion of significant confounders. Prospero registration number: CRD42020203791.

Central Nervous System Safety During Brief Analytic Treatment Interruption of Antiretroviral Therapy Within 4 Human Immunodeficiency Virus Remission Trials: An Observational Study in Acutely Treated People Living With Human Immunodeficiency Virus

BACKGROUND

The central nervous system (CNS) is a likely reservoir of human immunodeficiency virus (HIV), vulnerable to viral rebound, inflammation, and clinical changes upon stopping antiretroviral therapy (ART). It is critical to evaluate the CNS safety of studies using analytic treatment interruption (ATI) to assess HIV remission.

METHODS

Thirty participants who started ART during acute HIV infection underwent CNS assessments across 4 ATI remission trials. ART resumption occurred with plasma viral load >1000 copies/mL. CNS measures included paired pre- vs post-ATI measures of mood, cognitive performance, and neurologic examination, with elective cerebrospinal fluid (CSF) sampling, brain diffusion tensor imaging (DTI) and magnetic resonance spectroscopy (MRS).

RESULTS

Median participant age was 30 years old and 29/30 were male. Participants' median time on ART before ATI was 3 years, and ATI lasted a median of 35 days. Post-ATI, there were no differences in median mood scores or neurologic findings and cognitive performance improved modestly. During ATI, a low level of CSF HIV-1 RNA was detectable in 6 of 20 participants with plasma viremia, with no group changes in CSF immune activation markers or brain DTI measures. Mild worsening was identified in post-ATI basal ganglia total choline MRS, suggesting an alteration in neuronal membranes.

CONCLUSION

No adverse CNS effects were observed with brief, closely monitored ATI in participants with acutely treated HIV, except an MRS alteration in basal ganglia choline. Further studies are needed to assess CNS ATI safety in HIV remission trials, particularly for studies using higher thresholds to restart ART and longer ATI durations.

Abrupt and altered cell-type specific DNA methylation profiles in blood during acute HIV infection persists despite prompt initiation of ART

HIV-1 disrupts the host epigenetic landscape with consequences for disease pathogenesis, viral persistence, and HIV-associated comorbidities. Here, we examined how soon after infection HIV-associated epigenetic changes may occur in blood and whether early initiation of antiretroviral therapy (ART) impacts epigenetic modifications. We profiled longitudinal genome-wide DNA methylation in monocytes and CD4⁺ T lymphocytes from 22 participants in the RV254/SEARCH010 acute HIV infection (AHI) cohort that diagnoses infection within weeks after estimated exposure and immediately initiates ART. We identified monocytes harbored 22,697 differentially methylated CpGs associated with AHI compared to 294 in CD4⁺ T lymphocytes. ART minimally restored less than 1% of these changes in monocytes and had no effect upon T cells. Monocyte DNA methylation patterns associated with viral load, CD4 count, CD4/CD8 ratio, and longitudinal clinical phenotypes. Our findings suggest HIV-1 rapidly embeds an epigenetic memory not mitigated by ART and support determining epigenetic signatures in precision HIV medicine.

Trial Registration:NCT00782808 and NCT00796146.

The epigenetic marker, DNA methylation, plays a key role regulating the immune system during host-pathogen interactions. Using cell-type specific DNA methylation profiling, we explored whether epigenetic changes occurred soon after HIV infection and following early treatment with anti-HIV drugs. Acute infection was associated with early DNA methylation changes in purified monocytes and CD4⁺ T cells isolated from blood. In monocytes, rapid anti-HIV treatment minimally restored DNA methylation changes associated with infection and unexpectedly had no impact in CD4⁺ T cells. DNA methylation patterns before treatment informed long term clinical outcomes including CD4⁺ T cell counts and favorable clinical phenotypes. These findings identify candidates for consideration in epigenome editing approaches in HIV prevention, treatment, and cure strategies.

Effects of integrase inhibitor-based antiretroviral therapy on brain outcomes according to time since acquisition of HIV-1 infection

Integrase strand transfer inhibitors (INSTI) are a main component of the current antiretroviral regimens recommended for treatment of HIV infection. However, little is known about the impact of INSTI on neurocognition and neuroimaging. We developed a prospective observational trial to evaluate the effects of INSTI-based antiretroviral therapy on comprehensive brain outcomes (cognitive, functional, and imaging) according to the time since HIV-1 acquisition. We recruited men living with HIV who initiated antiretroviral therapy with INSTI < 3 months since the estimated date of HIV-1 acquisition (n = 12) and > 6 months since estimated date of HIV-1 acquisition (n = 15). We also recruited a group of matched seronegative individuals (n = 15). Assessments were performed at baseline (before initiation of therapy in HIV arms) and at weeks 4 and 48. Baseline cognitive functioning was comparable between the arms. At week 48, we did not find cognitive differences between starting therapy with INSTI earlier than 3 months or later than 6 months after acquisition of HIV-1 infection. Functional status was poorer in individuals diagnosed earlier. This effect recovered 48 weeks after initiation of therapy. Regarding brain imaging, we found that men living with HIV initiating antiretroviral therapy later experienced a greater decrease in medial orbitofrontal cortex over time, with expected negative repercussions for decision-making tasks.

Cognitive trajectories after treatment in acute HIV infection

OBJECTIVE

People with HIV continue to exhibit cognitive symptoms after suppressive antiretroviral therapy (ART). It remains unclear if initiating ART during acute HIV-1 infection (AHI) uniformly improves cognitive outcomes.

METHODS

Sixty-seven individuals (96% men, median age 28 years) initiated ART immediately after AHI diagnosis and maintained viral suppression for 6 years. They underwent a four-test neuropsychological battery that measured fine motor speed and dexterity, psychomotor speed, and executive functioning at baseline (pre-ART AHI), weeks 12, 24 and 96, and annually thereafter through week 288. Performances were standardized to calculate an overall (NPZ-4) score and frequencies of impaired cognitive performance (≤-1 SD on at least two tests, or ≤-2 SD on at least one test). Group-based trajectory analysis (GBTA) was applied to identify distinct neuropsychological trajectories modelled from baseline to week 288. Posthoc analyses examined HIV-1 and demographic factors that differed between trajectory subgroups.

RESULTS

NPZ-4 scores improved from baseline to week 96 (P < 0.001) and from weeks 96 to 288 (P < 0.001), with frequencies of impaired performance of 30, 6 and 2% at the respective time-points. The amplitude of NPZ-4 improvement throughout the period was more than 0.5 SD and beyond practice effects. GBTA identified three NPZ-4 trajectory subgroups that all showed improvement over-time. The subgroup with lowest baseline performance exhibited worse depressive symptoms at baseline (P = 0.04) and the largest improvement among the three. HIV-1 indices did not differ between the subgroups.

CONCLUSION

Cognitive performance improved in a sustained and stable manner after initiating ART during AHI. Largest improvements were seen in participants with worst baseline cognitive performance.

Minimal detection of cerebrospinal fluid escape after initiation of antiretroviral therapy in acute HIV-1 infection

OBJECTIVE

Despite suppression of HIV-1 replication in the periphery by antiretroviral therapy (ART), up to 10% of treated individuals have quantifiable HIV-1 in the CSF, termed CSF escape. CSF escape may be asymptomatic but has also been linked to progressive neurological disease, and may indicate persistence of HIV in the central nervous system (CNS). CSF escape has not yet been assessed after initiation of ART during acute HIV-1 infection (AHI).

DESIGN

Prospective cohort study.

SETTING

Major voluntary counseling and testing site in Bangkok, Thailand.

PARTICIPANTS

Participants identified and initiated on ART during AHI who received an optional study lumbar puncture at pre-ART baseline or after 24 or 96 weeks of ART.

MAIN OUTCOME MEASURES

Paired levels of CSF and plasma HIV-1 RNA, with CSF greater than plasma HIV-1 RNA defined as CSF escape.

RESULTS

Two hundred and four participants had paired blood and CSF sampling in at least one visit at baseline, week 24, or week 96. Twenty-nine participants had CSF sampling at all three visits. CSF escape was detected in 1/90 at week 24 (CSF HIV-1 RNA 2.50 log10 copies/ml, plasma HIV-1 RNA <50 copies/ml), and 0/55 at week 96.

CONCLUSION

Although levels of CSF HIV-1 RNA in untreated AHI are high, initiating treatment during AHI results in a very low rate of CSF escape in the first 2 years of treatment. Early treatment may improve control of HIV-1 within the CNS compared with treatment during chronic infection, which may have implications for long-term neurological outcomes and CNS HIV-1 persistence.

Clinical and laboratory impact of concomitant syphilis infection during acute HIV

INTRODUCTION

Cognitive impairment has been reported in people living with HIV-1 (PLWH) with prior syphilis, while PLWH who present with incident syphilis have reduced blood CD4 T-lymphocyte and elevated HIV-1 RNA levels. However, the clinical, virological and neurocognitive effects of syphilis during acute HIV-1 (AHI) remain unknown.

METHODS

Pre-antiretroviral therapy laboratory outcomes and neurocognitive performance in a four-test battery in the SEARCH10/RV254 AHI cohort were compared according to syphilis status, determined by serum Treponema pallidum haemagglutination (TPHA), Venereal Disease Research Laboratory (VDRL) and syphilis treatment history. Impaired cognitive performance was defined as having z-scores ≤ -1 in at least two tests or ≤ -2 in at least one test.

RESULTS

Out of 595 AHI participants (97% male, median age of 26 years and estimated duration of HIV-1 infection of 19 days), 119 (20%) had history of syphilis (TPHA-positive), of whom 51 (9%) had untreated syphilis (TPHA-positive/VDRL-positive/without prior treatment). Compared with those without syphilis (TPHA-negative), individuals with untreated syphilis had higher CD8 T-lymphocyte levels but not higher plasma HIV-1 RNA or lower CD4 T-lymphocyte levels. Taking into account estimated duration of HIV-1 infection (P < 0.001), and later Fiebig stages (III-V) (P < 0.001), those with untreated syphilis had higher CD8 T-lymphocyte levels (P = 0.049). Individuals with any syphilis (TPHA-positive), but not untreated syphilis, had higher odds of impaired cognitive performance than those without (P = 0.002).

CONCLUSIONS

During AHI, individuals with any history of syphilis (TPHA-positive) had poorer cognitive performance than those without syphilis. However, syphilis was not associated with worsened HIV disease measures as described in chronic infection.

The Impact of Antiretroviral Therapy on Neurocognitive Outcomes Among People Living with HIV in Low- and Middle-Income Countries (LMICs): A Systematic Review

Low and middle-income countries (LMICs) are the epicenter of the HIV epidemic. The scale-up of antiretroviral therapy (ART) has reduced mortality, but HIV-associated neurocognitive impairment (HANI) remains prevalent, which impacts functional performance, medication adherence, and quality of life. We aimed to evaluate the effect of ART on neurocognitive outcomes among people living with HIV/AIDS in LMICs and to identify determinants of these outcomes. We searched electronic databases and reference lists for studies published between 1996 and 2019. Two reviewers screened the primary studies for inclusion and performed the critical appraisal. Results were synthesized using the 'Synthesis without meta-analysis' approach through simple vote counting. We identified 31 studies conducted across four regions (Africa, Asia, South America, and Eastern Europe). Nine studies were cross-sectional, 15 were prospective, and seven were randomized controlled trials. The majority of the articles showed improved neurocognitive performance with ART use but found no association with treatment duration, regimen, central penetrating effectiveness, and conventional biomarkers. Despite the lack of appropriate norms and not accounting for practice effect in most studies, the evidence suggests ART is useful in the treatment of HIV-associated neurocognitive impairment (HANI) but limited in addressing legacy effects, and peripheral, and central viral reservoirs. Improved early ART treatment programs, viral reservoir eradication strategies, and identification of novel biomarkers will be critical in efforts to minimize HIV-associated neurocognitive impairment. PROSPERO registration: CRD42020152908.

Efficacy, pharmacokinetics and neurocognitive performance of dual, NRTI-sparing antiretroviral therapy in acute HIV-infection

OBJECTIVES

The aim of this study was to evaluate penetration of antiretrovirals into compartments and efficacy of a dual, NRTI-sparing regimen in acute HIV infection (AHI).

DESIGN

Single-arm, open-label pilot study of participants with AHI initiating ritonavir-boosted darunavir 800 mg once daily and etravirine 400 mg once daily or 200 mg twice daily within 30 days of AHI diagnosis.

METHODS

Efficacy was defined as HIV RNA less than 200 copies/ml by week 24. Optional sub-studies included pharmacokinetics analysis from genital fluids (weeks 0-4, 12, 48), cerebrospinal fluid (CSF) (weeks 2-4, 24 and 48) and endoscopic biopsies (weeks 4-12 and 36-48). Neuropsychological performance was assessed at weeks 0, 24 and 48.

RESULTS

Fifteen AHI participants were enrolled. Twelve (80%) participants achieved HIV RNA less than 200 copies/ml by week 24. Among 12 participants retained through week 48, nine (75%) remained suppressed to less than 50 copies/ml. The median time from ART initiation to suppression less than 200 and less than 50 copies/ml was 59 and 86 days, respectively. The penetration ratios for etravirine and darunavir in gut associated lymphoid tissue were 19.2 and 3.05, respectively. Most AHI participants achieving viral suppression experienced neurocognitive improvement. Of the three participants without overall improvement in neurocognitive functioning as measured by impairment ratings (more than two tests below 1 SD), two had virologic failure.

CONCLUSION

NRTI-sparing ART started during AHI resulted in rapid viral suppression similar to NRTI-based regimens. More novel and compact two-drug treatments for AHI should be considered. Early institution of ART during AHI appears to improve overall neurocognitive function and may reduce the risk of subsequent neurocognitive impairment. CLINICALTRIALS.GOV:: NCT00855413.

Predictors of incomplete viral response and virologic failure in patients with acute and early HIV infection. Results of Italian Network of ACuTe HIV InfectiON (INACTION) cohort

OBJECTIVES

The aim of this study was to evaluate the factors that can influence an incomplete viral response (IVR) after acute and early HIV infection (AEHI).

METHODS

This was a retrospective, observational study including patients with AEHI (Fiebig stages I-V) diagnosed between January 2008 and December 2014 at 20 Italian centres. IVR was defined by: (1) viral blip (51-1000 HIV-1 RNA copies/mL after achievement of < 50 HIV-1 RNA copies/mL); (2) virologic failure [> 1000 copies/mL after achievement of < 200 copies/mL, or ≥ 200 copies/mL after 24 weeks on an antiretroviral therapy (ART)]; (3) suboptimal viral response (> 50 copies/mL after 48 weeks on ART or two consecutive HIV-1 RNA levels with ascending trend during ART). Cox regression analysis was used to calculate the hazard ratios (HRs) and 95% confidence intervals (95% CIs) for IVR.

RESULTS

In all, 263 patients were studied, 227 (86%) males, with a median [interquartile range (IQR)] age of 38 (30-46) years. During a median follow-up of 13.0 (5.7-31.1) months, 38 (14.4%) had IVR. The presence of central nervous system (CNS) symptoms was linked to a higher risk of IVR (HR = 4.70, 95% CI: 1.56-14.17), while a higher CD4/CD8 cell count ratio (HR = 0.13, 95% CI: 0.03-0.51 for each point increase) and first-line ART with three-drug regimens recommended by current guidelines (HR = 0.40, 95% CI: 0.18-0.91 compared with other regimens including four or five drugs, older drugs or non-standard backbones) were protective against IVR.

CONCLUSIONS

Patients with lower CD4/CD8 ratio and CNS symptoms could be at a higher risk of IVR after AEHI. The use of recommended ART may be relevant for improving short-term viral efficacy in this group of patients.

Neurologic Complications of Acute HIV Infection

Purpose of Review

This review focuses on the pathophysiology of acute HIV infection (AHI) and related central nervous system (CNS) pathology, the clinical characteristics of neurologic complications of AHI, and the implications of the CNS reservoir and viral escape for HIV treatment and cure strategies.

Recent Findings

Recent studies in newly seroconverted populations show a high prevalence of peripheral neuropathy and cognitive dysfunction in AHI, even though these findings have been classically associated with chronic HIV infection. HIV cure strategies such as the "shock and kill" strategy are currently being studied in vitro and even in small clinical trials, though the CNS as a reservoir for latent HIV poses unique barriers to these treatment strategies.

Summary

Limited point of care diagnostic testing for AHI and delayed recognition of infection continue to lead to under-recognition and under-reporting of neurologic manifestations of AHI. AHI should be on the differential for a broad range of neurological conditions, from Bell's palsy, peripheral neuropathy, and aseptic meningitis, to more rare manifestations such as ADEM, AIDP, meningo-radiculitis, transverse myelitis, and brachial neuritis. Treatment for these conditions involves early initiation of antiretroviral therapy (ART) and then standard presentation-specific treatments. Current HIV cure strategies under investigation include bone marrow transplant, viral reservoir re-activation and eradication, and genome and epigenetic viral targeting. However, CNS penetration by HIV-1 occurs early on in the disease course with the establishment of the CNS viral reservoir and is an important limiting factor for these therapies.

Role of T Lymphocytes in HIV Neuropathogenesis

PURPOSE OF REVIEW

The purpose of this review is to summarize the current knowledge on the role of CD4⁺ T lymphocytes leading to HIV assault and persistence in the central nervous system (CNS) and the elimination of HIV-infected CNS resident cells by CD8⁺ T lymphocytes.

RECENT FINDINGS

HIV targets the CNS early in infection, and HIV-infected individuals suffer from mild forms of neurological impairments even under antiretroviral therapy (ART). CD4⁺ T cells and monocytes mediate HIV entry into the brain and constitute a source for HIV persistence and neuronal damage. HIV-specific CD8⁺ T cells are also massively recruited in the CNS in acute infection to control viral replication but cannot eliminate HIV-infected cells within the CNS. This review summarizes the involvement of CD4⁺ T cells in seeding and maintaining HIV infection in the brain and describes the involvement of CD8⁺ T cells in HIV neuropathogenesis, playing a role still to be deciphered, either beneficial in eliminating HIV-infected cells or deleterious in releasing inflammatory cytokines.

Regional brain volumetric changes despite 2 years of treatment initiated during acute HIV infection

OBJECTIVE

To assess changes in regional brain volumes after 24 months among individuals who initiated combination antiretroviral therapy (cART) within weeks of HIV exposure.

DESIGN

Prospective cohort study of Thai participants in the earliest stages of HIV-1infection.

METHODS

Thirty-four acutely HIV-infected individuals (AHI; Fiebig I-V) underwent brain magnetic resonance (MR) imaging and MR spectroscopy at 1.5 T and immediately initiated cART. Imaging was repeated at 24 months. Regional brain volumes were quantified using FreeSurfer's longitudinal pipeline. Voxel-wise analyses using tensor-based morphometry (TBM) were conducted to verify regional assessments. Baseline brain metabolite levels, blood and cerebrospinal fluid biomarkers assessed by ELISA, and peripheral blood monocyte phenotypes measured by flow cytometry were examined as predictors of significant volumetric change.

RESULTS

Participants were 31 ± 8 years old. The estimated mean duration of infection at cART initiation was 15 days. Longitudinal analyses revealed reductions in volumes of putamen (P < 0.001) and caudate (P = 0.006). TBM confirmed significant atrophy in the putamen and caudate, and also in thalamic and hippocampal regions. In exploratory post-hoc analyses, higher baseline frequency of P-selectin glycoprotein ligand-1 (PSGL-1)-expressing total monocytes correlated with greater caudate volumetric decrease (ρ = 0.67, P = 0.017), whereas the baseline density of PSGL-1-expressing inflammatory (CD14CD16) monocytes correlated with putamen atrophy (ρ = 0.65, P = 0.022).

CONCLUSION

Suppressive cART initiated during AHI may not prevent brain atrophy. Volumetric decrease appears greater than expected age-related decline, although examination of longitudinal change in demographically similar HIV-uninfected Thai individuals is needed. Mechanisms underlying progressive HIV-related atrophy may include early activation and enhanced adhesive and migratory capacity of circulating monocyte populations.

Prefrontal Recruitment Mitigates Risk-Taking Behavior in Human Immunodeficiency Virus-Infected Young Adults

Background

Human immunodeficiency virus (HIV)-infected (HIV+) young adults often engage in risk-taking behavior. However, the disruptive effects of HIV on the neurobiological underpinnings of risky decision making are not well understood.

Methods

Risky decision making, measured via the Iowa Gambling Task (IGT), was compared voxel-wise to resting cerebral blood flow (rCBF) acquired via arterial spin labeling. Separate topographical maps were obtained for HIV-uninfected (HIV-; n = 62) and HIV+ (n = 41) young adults (18-24 years old) and were compared to the full cohort of participants. For the HIV+ group, rCBF was compared to recent and nadir CD4.

Results

IGT performance was supported by rCBF in 3 distinct brain regions: regions I, II, and III. The relationship between IGT performance and rCBF in HIV+ individuals was most robust in region I, the ventromedial prefrontal and insular cortices. Region II contained strong relationships for both HIV- and HIV+. Region III, dorsolateral prefrontal and posterior cingulate cortices, contained relationships that were strongest for HIV- controls. IGT performance was intact among HIV+ participants with higher rCBF in either region I or region III. By contrast, performance was worse among HIV+ individuals with lower rCBF in both regions I and III when compared to HIV- controls (P = .01). rCBF in region III was reduced in HIV+ compared with HIV- individuals (P = .04), and positively associated with nadir CD4 cell count (P = .02).

Conclusions

Recruitment of executive systems (region III) mitigates risk-taking behavior in HIV+ and HIV- individuals. Recruitment of reward systems (region I) mitigates risk-taking behavior when region III is disrupted due to immunological compromise. Identifying individual recruitment patterns may aid anatomically directed therapeutics or psychosocial interventions.

Neurologic Complications of Human Immunodeficiency Virus Infection

PURPOSE OF REVIEW

Widespread use of antiretroviral therapy (ART) has led to near-normal life expectancy in people with human immunodeficiency virus (HIV) infection. However, neurologic complications of HIV remain common; can affect any part of the neuraxis; and are due to direct effects of the virus, immunosuppression because of untreated HIV infection, aberrant immune responses in the setting of ART initiation, and ART toxicities.

RECENT FINDINGS

HIV-associated neurocognitive disorder (HAND) remains one of the most common neurologic complications of HIV encountered today, but milder forms predominate in people on ART. No specific treatments for HAND exist, but small trials and epidemiologic evidence suggest paroxetine, intranasal insulin, and maraviroc may have utility in its treatment; further trials of these agents are ongoing. Widespread ART use has decreased the incidence of central nervous system opportunistic infections, but prognosis often remains poor in those who develop opportunistic infections. High-titer positive serum cryptococcal antigen is strongly predictive of cryptococcal meningitis and provides a tool to enhance diagnosis in areas with limited resources. HIV is an independent risk factor for stroke, and accelerated aging associated with HIV infection results in neurologic diseases of older age occurring at much younger ages in individuals infected with HIV. Ongoing HIV replication in the CSF despite peripheral virologic suppression may contribute to the development of HAND and may not improve despite adjusting the ART regimen to increase central nervous system penetrance.

SUMMARY

Neurologists are likely to encounter patients infected with HIV in clinical practice. This article reviews the presentation, diagnosis, and management of the most common neurologic conditions associated with HIV infection and ART.

Efficient Expression of HIV in Immunocompetent Mouse Brain Reveals a Novel Nonneurotoxic Viral Function in Hippocampal Synaptodendritic Injury and Memory Impairment

HIV causes neurodegeneration and dementia in AIDS patients, but its function in milder cognitive impairments in virologically suppressed patients on antiretroviral therapy is unknown. Such patients are immunocompetent, have low peripheral and brain HIV burdens, and show minimal brain neuropathology. Using the model of HIV-related memory impairment in EcoHIV-infected conventional mice, we investigated the neurobiological and cognitive consequences of efficient EcoHIV expression in the mouse brain after intracerebral infection. HIV integrated and persisted in an expressed state in brain tissue, was detectable in brain monocytic cells, and caused neuroinflammatory responses and lasting spatial, working, and associative memory impairment. Systemic antiretroviral treatment prevented direct brain infection and memory dysfunction indicating the requirement for HIV expression in the brain for disease. Similarly inoculated murine leukemia virus used as a control replicated in mouse brain but not in monocytic cells and was cognitively benign, linking the disease to HIV-specific functions. Memory impairment correlated in real time with hippocampal dysfunction shown by defective long-term potentiation in hippocampal slices ex vivo and with diffuse synaptodendritic injury in the hippocampus reflected in significant reduction in microtubule-associated protein 2 and synapsin II staining. In contrast, there was no evidence of overt neuronal loss in this region as determined by neuron-specific nuclear protein quantification, TUNEL assay, and histological observations. Our results reveal a novel capacity of HIV to induce neuronal dysfunction and memory impairment independent of neurotoxicity, distinct from the neurotoxicity of HIV infection in dementia.IMPORTANCE HIV neuropathogenesis has been attributed in large measure to neurotoxicity of viral proteins and inflammatory factors produced by infected monocytic cells in the brain. We show here that HIV expression in mouse brain causes lasting memory impairment by a mechanism involving injury to hippocampal synaptodendritic arbors and neuronal function but not overt neuronal loss in the region. Our results mirror the observation of minimal neurodegeneration in cognitively impaired HIV patients on antiretroviral therapy and demonstrate that HIV is nonneurotoxic in certain brain abnormalities that it causes. If neurons comprising the cognition-related networks survive HIV insult, at least for some time, there is a window of opportunity for disease treatment.

A culturally fair test of processing speed: Construct validity, preliminary normative data, and effects of HIV infection on performance in South African adults

OBJECTIVES

Impaired processing speed (PS) is a feature of cognitive profiles associated with neurological disorders particularly prevalent in low- or middle-income countries (LMICs). However, commonly used PS tests are not validated for use in LMICs. We assessed, using a sample of healthy South African adults, the construct validity of PS tests contained within NeuroScreen (a tablet-based application and test battery designed to be culturally fair), and established preliminary normative data for those tests (Study 1). Moreover, because South Africa has the highest population prevalence of people living with HIV and PS deficits are a core feature of HIV-associated cognitive impairment, we assessed whether NeuroScreen could detect PS impairment in a sample of HIV-infected South African adults (Study 2).

METHODS

In Study 1 (N = 112 healthy adults) and Study 2 (the Study 1 sample, plus n = 102 HIV-infected adults), we administered Neuroscreen and a standardized paper-and-pencil neuropsychological test battery.

RESULTS

In Study 1, factor analyses indicated that NeuroScreen PS scores loaded onto one factor and converged with scores on paper-and-pencil PS tests. Regression modeling indicated that age significantly predicted NeuroScreen PS performance (i.e., younger participants performed better). In Study 2, HIV-infected participants performed significantly more poorly on NeuroScreen PS tests than their HIV-uninfected counterparts. Moreover, a significantly larger proportion of HIV-infected participants displayed impaired PS when judged against the regression-based norms.

CONCLUSIONS

These results suggest that NeuroScreen has cross-cultural utility in assessing adult PS performance, and that it might be useful in tracking trajectories of PS decline within HIV infection. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Intranasal insulin therapy reverses hippocampal dendritic injury and cognitive impairment in a model of HIV-associated neurocognitive disorders in EcoHIV-infected mice

OBJECTIVE

Almost half of HIV-positive people on antiretroviral therapy have demonstrable mild neurocognitive impairment (HIV-NCI), even when virologically suppressed. Intranasal insulin therapy improves cognition in Alzheimer's disease and diabetes. Here we tested intranasal insulin therapy in a model of HIV-NCI in EcoHIV-infected conventional mice.

DESIGN AND METHODS

Insulin pharmacokinetics following intranasal administration to mice was determined by ELISA. Mice were inoculated with EcoHIV to cause NCI; 23 days or 3 months after infection they were treated daily for 9 days with intranasal insulin (2.4 IU/mouse) and examined for NCI in behavioral tests and HIV burdens by quantitative PCR. Some animals were tested for hippocampal neuronal integrity by immunostaining and expression of neuronal function-related genes by real time-quantitative PCR. The effect of insulin treatment discontinuation on cognition and neuropathology was also examined.

RESULTS

Intranasal insulin administration to mice resulted in μIU/ml levels of insulin in cerebrospinal fluid with a half-life of about 2 h, resembling pharmacokinetic parameters of patients receiving 40 IU. Intranasal insulin treatment starting 23 days or 3 months after infection completely reversed NCI in mice. Murine NCI correlated with reductions in hippocampal dendritic arbors and downregulation of neuronal function genes; intranasal insulin reversed these changes coincident with restoration of cognitive acuity, but they returned within 24 h of treatment cessation. Intranasal insulin treatment reduced brain HIV DNA when started 23 but not 90 days after infection.

CONCLUSION

Our preclinical studies support the use of intranasal insulin administration for treatment of HIV-NCI and suggest that some dendritic injury in this condition is reversible.

Where latest advances in HIV are shared: 21st Bangkok International Symposium on HIV Medicine

Bangkok International Symposium on HIV Medicine is the largest regional conference on clinical HIV medicine in Southeast Asia. Held annually during the third week of January and spanning 3 days, the symposium provides updates on HIV and co-infection treatment and prevention. It is sponsored by HIV Netherlands Australia Thailand Research Collaboration (HIV-NAT), the first and largest clinical research center in Thailand and region. HIV-NAT was founded by the late David Cooper, late Joep Lange and Emeritus Praphan Phanuphak, who dedicated their lives to making HIV care and treatment accessible to people living with HIV in Thailand and throughout the developing world. The symposium continues its tradition of bringing the latest information in the field of HIV medicine to healthcare professionals.

Global HIV neurology: a comprehensive review

: Neurological conditions associated with HIV remain major contributors to morbidity and mortality and are increasingly recognized in the aging population on long-standing combination antiretroviral therapy (cART). Importantly, growing evidence shows that the central nervous system (CNS) may serve as a reservoir for viral replication, which has major implications for HIV eradication strategies. Although there has been major progress in the last decade in our understanding of the pathogenesis, burden, and impact of neurological conditions associated with HIV infection, significant scientific gaps remain. In many resource-limited settings, antiretrovirals considered second or third line in the United States, which carry substantial neurotoxicity, remain mainstays of treatment, and patients continue to present with severe immunosuppression and CNS opportunistic infections. Despite this, increased global access to cART has coincided with an aging HIV-positive population with cognitive sequelae, cerebrovascular disease, and peripheral neuropathy. Further neurological research in low-income and middle-income countries (LMICs) is needed to address the burden of neurological complications in HIV-positive patients, particularly regarding CNS viral reservoirs and their effects on eradication.

Structural and functional brain imaging in acute HIV

Background

HIV RNA is identified in cerebrospinal fluid (CSF) within eight days of estimated viral exposure. Neurological findings and impaired neuropsychological testing performance are documented in a subset of individuals with acute HIV infection (AHI). The purpose of this study was to determine whether microstructural white matter and resting-state functional connectivity (rsFC) are disrupted in AHI.

Methods

We examined 49 AHI (100% male; mean age = 30 ± SD 9.9) and 23 HIV-uninfected Thai participants (78% male; age = 30 ± 5.5) with diffusion tensor imaging (DTI) and rsFC acquired at 3 Tesla, and four neuropsychological tests (summarized as NPZ-4). MRI for the AHI group was performed prior to combination antiretroviral treatment (ART) in 26 participants and on average two days (range:1–5) after ART in 23 participants. Fractional anisotropy (FA), mean (MD), axial (AD), and radial diffusivity (RD) were quantified for DTI. Seed-based voxelwise rsFC analyses were completed for the default mode (DMN), fronto-parietal, and salience and 6 subcortical networks. rsFC and DTI analyses were corrected for family-wise error, with voxelwise comparisons completed using t-tests. Group-specific voxelwise regressions were conducted to examine relationships between imaging indices, HIV disease variables, and treatment status.

Results

The AHI group had a mean (SD) CD4 count of 421(234) cells/mm³ plasma HIV RNA of 6.07(1.1) log₁₀ copies/mL and estimated duration of infection of 20(5.5) days. Differences between AHI and CO groups did not meet statistical significance for DTI metrics. Within the AHI group, voxelwise analyses revealed associations between brief exposure to ART and higher FA and lower RD and MD bilaterally in the corpus callosum, corona radiata, and superior longitudinal fasciculus (p < 0.05). Diffusion indices were unrelated to clinical variables or NPZ-4. The AHI group had reduced rsFC between left parahippocampal cortex (PHC) of the DMN and left middle frontal gyrus compared to CO (p < 0.002). Within AHI, ART status was unrelated to rsFC. However, higher CD4 cell count associated with increased rsFC for the right lateral parietal and PHC seeds in the DMN. Direct associations were noted between NPZ-4 correspond to higher rsFC of the bilateral caudate seed (p < 0.002).

Conclusions

Study findings reveal minimal disruption to structural and functional brain integrity in the earliest stages of HIV. Longitudinal studies are needed to determine if treatment with ART initiated in AHI is sufficient to prevent the evolution of brain dysfunction identified in chronically infected individuals.

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DTI indicates no significant differences between acute HIV and uninfected controls.

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rsfMRI reflects limited reduced rsFC in acute HIV compared to uninfected controls.

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Relatively preserved brain integrity identified in acute HIV vs uninfected controls.

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Cognitive testing and CD4 lymphocyte counts associate with rsFC activity in acute HIV.

Neurological Complications of HIV Infection

PURPOSE OF REVIEW

HIV-associated neurocognitive disorders (HAND) are common in patients with HIV disease, even during suppressive combination antiretroviral therapy (cART). This review article addresses the pathogenesis of HAND, focusing on important findings from the last 5 years.

RECENT FINDINGS

While HIV-associated dementia is now rare in settings with cART availability, mild forms of HAND are increasing in prevalence. Biomarkers of cellular injury, such as neurofilament light chain and neopterin, can detect early stages of neuroinflammation associated with HIV infection and are increased even in asymptomatic individuals with chronic HIV infection. Several recent studies form a growing body of evidence that HIV can infect and replicate in monocytes and that blocking monocyte activity can potentially improve neurological outcomes in HIV. Early cART may also prevent HAND. Understanding the multifactorial causes of CNS infection and inflammation is critical to devising treatment and preventive strategies for HAND.

Cognitive Impairment and Persistent CNS Injury in Treated HIV

The implementation of combination antiretroviral therapy (cART) has changed HIV infection into a chronic illness, conveying extensive benefits, including greater longevity and advantages for the central nervous system (CNS). However, studies increasingly confirm that the CNS gains are incomplete, with reports of persistent immune activation affecting the CNS despite suppression of plasma HIV RNA. The rate of cognitive impairment is unchanged, although severity is generally milder than in the pre-cART era. In this review, we discuss cognitive outcomes from recently published clinical HIV studies, review observations on HIV biomarkers for cognitive change, and emphasize longitudinal imaging findings. Additionally, we summarize recent studies on CNS viral invasion, CD8 encephalitis, and how CNS involvement during the earliest stages of infection may set the stage for later cognitive manifestations.

Human Endogenous Retrovirus-K and TDP-43 Expression Bridges ALS and HIV Neuropathology

Despite the repetitive association of endogenous retroviruses in human disease, the mechanisms behind their pathological contributions remain to be resolved. Here we discuss how neuronal human endogenous retrovirus-K (HERV-K) expression in human immunodeficiency virus (HIV)-infected individuals is a distinct pathological aspect of HIV-associated neurological conditions, such as HIV encephalitis and HIV-associated neurocognitive disorders. Enhanced neuronal HERV-K levels were observed in the majority of HIV-infected individuals, and to a higher degree in brain tissue marked by HIV replication. Moreover, we highlight an important neuropathological overlap between amyotrophic lateral sclerosis and HIV encephalitis, that being the formation of neurotoxic TDP-43 deposits in neurons. Herein, we argue for enhanced transdisciplinary research in the field of ERV biology, using an example of how HERV-K expression has novel mechanistic and therapeutic implications for HIV neuropathology.

Chronic low-level expression of HIV-1 Tat promotes a neurodegenerative phenotype with aging

The widespread use of combinational antiretroviral therapies (cART) in developed countries has changed the course of Human Immunodeficiency Virus (HIV) infection from an almost universally fatal disease to a chronic infection for the majority of individuals. Although cART has reduced the severity of neurological damage in HIV-infected individuals, the likelihood of cognitive impairment increases with age, and duration of infection. As cART does not suppress the expression of HIV non-structural proteins, it has been proposed that a constitutive production of HIV regulatory proteins in infected brain cells may contribute to neurological damage. However, this assumption has never been experimentally tested. Here we take advantage of the leaky tetracycline promoter system in the Tat-transgenic mouse to show that a chronic very low-level expression of Tat is associated with astrocyte activation, inflammatory cytokine expression, ceramide accumulation, reductions in brain volume, synaptic, and axonal damage that occurs over a time frame of 1 year. These data suggest that a chronic low-level production of Tat may contribute to progressive neurological damage in virally suppressed HIV-infected individuals.

Neurologic Complications in Treated HIV-1 Infection

Effective combination antiretroviral therapy has transformed HIV infection into a chronic disease, with HIV-infected individuals living longer and reaching older age. Neurological disease remains common in treated HIV, however, due in part to ongoing inflammation and immune activation that persist in chronic infection. In this review, we highlight recent developments in our understanding of several clinically relevant neurologic complications that can occur in HIV infection despite treatment, including HIV-associated neurocognitive disorders, symptomatic CSF escape, cerebrovascular disease, and peripheral neuropathy.

Modifications in acute phase and complement systems predict shifts in cognitive status of HIV-infected patients

BACKGROUND

The prevalence of HIV-associated neurocognitive disorders (HAND) has not changed considerably in the last two decades. Potent antiretroviral therapy has shifted the severity of HAND to milder phenotypes, but excess morbidity and mortality continue to be associated with HAND. Changes in numerous markers of immune function, inflammation, and cellular stress have been repeatedly associated with HAND, but the underlying systems that drive these changes have not been identified.

METHOD

In this study, we used systems informatics to interrogate the cerebrospinal fluid proteomic content of longitudinal samples obtained from HIV-infected adults with stably unimpaired, stably impaired, worsening, or improving neurocognitive performance.

RESULTS AND CONCLUSION

The patterns of change in cerebrospinal fluid protein content implicated the induction of acute phase and complement systems as important regulators of neurocognitive status. Worsening neurocognitive performance was preceded by induction of acute phase and complement systems, whereas improving neurocognitive performance was preceded by a downregulation of these systems.

Treating HIV Infection in the Central Nervous System

Combination antiretroviral treatment is associated with clear benefits in HIV-positive subjects, and is also effective in the central nervous system (CNS), meaning HIV-associated dementia is now an uncommon event. Nevertheless, a significant number of patients show symptoms of neurocognitive impairment which may negatively affect their quality of life. Although several risk factors for HIV-associated neurocognitive disorders have been identified, there is no clear recommendation for their prevention and management. In this review, the penetration of drugs into the cerebrospinal fluid/CNS is discussed as well as the viral and clinical consequences associated with higher/lower compartmental exposure. We also review the potential interventions according to the currently identified underlying mechanisms, including persistent CNS immune activation, legacy effects, low-level viral replication and escape, co-morbidities, and antiretroviral-associated direct and indirect 'neurotoxicity'. Adjunctive therapies and interventions (including neuro-rehabilitation) are then briefly discussed. The treatment of HIV infection in the CNS is a complex area of therapeutics requiring multidisciplinary interventions and further study.

Cerebrospinal fluid viral load and neopterin in HIV-positive patients with undetectable viraemia

BACKGROUND

Cerebrospinal fluid (CSF) HIV RNA is commonly used as a marker of compartmental antiviral activity in HIV-positive patients. Undetectable CSF HIV RNA levels have been associated with low CSF neopterin levels and better neurocognitive performances. The aim of this study was to analyse the prevalence and predictors of non-detectable CSF HIV RNA using a commercial assay.

METHODS

In adult HIV-positive HAART-treated patients with confirmed plasma HIV RNA <50 copies/ml, CSF HIV RNA (with Roche Amplicor Assay) and neopterin were measured.

RESULTS

112 adult patients were included. Plasma and CSF HIV RNA were non-detectable (target not detected [TND]) in 29 (25.9%) and 36 (32.1%) patients, respectively. CSF TND was observed more frequently in patients with plasma TND (P=0.005, OR=3.87). CSF neopterin levels were associated with age (rho =0.333, P=0.002) and current (rho= -0.272, P=0.015) and nadir (rho =-0.240, P=0.038) CD4⁺ T-lymphocytes; the lowest CSF neopterin concentration was observed in patients with CSF TND versus other viral load strata (0.62 mg/dl versus 0.78 mg/dl; P=0.048).

CONCLUSIONS

Efficaciously treated HIV-positive patients with detectable plasma HIV RNA might imperfectly control CSF viral replication. Prospective studies addressing the management and neurocognitive consequences of CSF low-level viraemia are warranted.

Neurologic signs and symptoms frequently manifest in acute HIV infection

OBJECTIVE

To determine the incidence, timing, and severity of neurologic findings in acute HIV infection (pre-antibody seroconversion), as well as persistence with combination antiretroviral therapy (cART).

METHODS

Participants identified with acute HIV were enrolled, underwent structured neurologic evaluations, immediately initiated cART, and were followed with neurologic evaluations at 4 and 12 weeks. Concurrent brain MRIs and both viral and inflammatory markers in plasma and CSF were obtained.

RESULTS

Median estimated HIV infection duration was 19 days (range 3-56) at study entry for the 139 participants evaluated. Seventy-three participants (53%) experienced one or more neurologic findings in the 12 weeks after diagnosis, with one developing a fulminant neurologic manifestation (Guillain-Barré syndrome). A total of 245 neurologic findings were noted, reflecting cognitive symptoms (33%), motor findings (34%), and neuropathy (11%). Nearly half of the neurologic findings (n = 121, 49%) occurred at diagnosis, prior to cART initiation, and most of these (n = 110, 90%) remitted concurrent with 1 month on treatment. Only 9% of neurologic findings (n = 22) persisted at 24 weeks on cART. Nearly all neurologic findings (n = 236, 96%) were categorized as mild in severity. No structural neuroimaging abnormalities were observed. Participants with neurologic findings had a higher mean plasma log10 HIV RNA at diagnosis compared to those without neurologic findings (5.9 vs 5.4; p = 0.006).

CONCLUSIONS

Acute HIV infection is commonly associated with mild neurologic findings that largely remit while on treatment, and may be mediated by direct viral factors. Severe neurologic manifestations are infrequent in treated acute HIV.

HIV-associated neurocognitive disorder--pathogenesis and prospects for treatment

In the past two decades, several advancements have improved the care of HIV-infected individuals. Most importantly, the development and deployment of combination antiretroviral therapy (CART) has resulted in a dramatic decline in the rate of deaths from AIDS, so that people living with HIV today have nearly normal life expectancies if treated with CART. The term HIV-associated neurocognitive disorder (HAND) has been used to describe the spectrum of neurocognitive dysfunction associated with HIV infection. HIV can enter the CNS during early stages of infection, and persistent CNS HIV infection and inflammation probably contribute to the development of HAND. The brain can subsequently serve as a sanctuary for ongoing HIV replication, even when systemic viral suppression has been achieved. HAND can remain in patients treated with CART, and its effects on survival, quality of life and everyday functioning make it an important unresolved issue. In this Review, we describe the epidemiology of HAND, the evolving concepts of its neuropathogenesis, novel insights from animal models, and new approaches to treatment. We also discuss how inflammation is sustained in chronic HIV infection. Moreover, we suggest that adjunctive therapies--treatments targeting CNS inflammation and other metabolic processes, including glutamate homeostasis, lipid and energy metabolism--are needed to reverse or improve HAND-related neurological dysfunction.