Discordant CSF/plasma HIV-1 RNA in patients with unexplained low-level viraemia

Asymptomatic Cerebrospinal Fluid HIV-1 Escape: Incidence and Consequences

BACKGROUND

The incidence and clinical relevance of asymptomatic cerebrospinal fluid escape (CSFE) during antiretroviral therapy (ART) is uncertain. We examined the impact and incidence of asymptomatic CSFE in a Swedish HIV cohort.

METHODS

Neuroasymptomatic people with HIV (PWH) who have been on ART for at least 6 months with suppressed plasma viral load were followed longitudinally. CSFE was defined as either increased CSF HIV-1 RNA with concurrent plasma suppression or CSF HIV-1 RNA exceeding that in plasma when both were quantifiable. Paired CSF and plasma were analyzed for HIV-1 RNA, neopterin, neurofilament light protein (NfL), white blood cell (WBC) count, and albumin ratio.

RESULTS

Asymptomatic CSFE (cutoff 50 copies/mL) was found in 4 of 173 PWH (2%) and 5 of 449 samples (1%). The corresponding proportions were 8% of PWH and 4% for samples using a 20 copies/mL cutoff for CSF HIV-1 RNA. CSFE samples (cutoff 20 copies/mL) had a 25% higher geometric mean of CSF neopterin (P = .01) and 8% higher albumin ratio (P = .04) compared to samples without CSFE. No differences were observed in CSF NfL levels (P = .8). The odds ratio for increased CSF WBC (≥ 3 cells/μL) in samples with CSFE was 3.9 (P = .004), compared to samples without elevated CSF viral load.

CONCLUSIONS

Asymptomatic CSFE was identified in only 4 (2%) PWH, with no cases of continuous CSFE observed. Increased CSF HIV-1 RNA was associated with biomarkers of CNS immune activation and blood-brain barrier impairment, but not with biomarkers of neuronal injury.

The incidence of symptomatic CSF viral escape in patients on antiretroviral therapy in western India: a retrospective cohort study

Antiretroviral treatment (ART) effectively suppresses viral loads in both plasma and cerebrospinal fluid (CSF). Patients with discordant plasma and CSF viral loads may experience chronic-progressive or fluctuating neurocognitive dysfunctions. This study examined the incidence of symptomatic CSF viral escape (CSFVE) in patients receiving ART. This retrospective cohort study was conducted between 2000 and 2023. The primary outcome measure was the incidence of symptomatic CSFVE. Nonparametric Mann-Whitney U and Fisher exact/χ 2 tests were applied for continuous and categorical variables, respectively. The cumulative incidence function with Gray's test was used to compare the incidence of CSFVE across the treatment regimens. During the study period, 52 of the 8415 patients were diagnosed with CSFVE. The median duration of HIV diagnosis in patients with CSF VE was 150 (12-288) months, with a median nadir CD4 + T-cell count 96.5 (13-601 cells/L)], and 75% of the patients were on a ritonavir-boosted protease inhibitor (PI/r) regimen. The cumulative incidence of symptomatic CSFVE at a follow-up of 14 years was 1% (95% CI, 0-1%). PI/r (HR 34.73; 95% CI 13.5 to 89.4; p < 0.001) and integrase strand transfer inhibitor (INSTI) (HR 3.42; 95% CI 1.94 to 6.02; p < 0.001) regimens were significantly more likely to be associated with CSFVE than the Non-nucleoside reverse transcriptase inhibitors (NNRTIs) regimens. NNRTIs had the lowest risk of CSFVE compared to the PI/r and INSTI regimens. A rapid and complete recovery is possible with symptomatic CSFVE if it is diagnosed and treated early.

Cerebrospinal fluid HIV RNA escape syndrome

A 54-year-old man with treated HIV developed a subacute deterioration of speech, mobility and cognition. Cerebrospinal fluid (CSF) analysis showed a raised protein and a discordant CSF HIV RNA paired with plasma HIV RNA, confirming the diagnosis of CSF HIV RNA escape syndrome. It is important to consider this diagnosis in people with treated HIV who develop new neurological symptoms.

Symptomatic and Asymptomatic Neurocognitive Impairment, ART Adherence and HIV Control: A 4-Year Observational Study

We assessed whether symptomatic neurocognitive impairment (NCI) and asymptomatic NCI -of which the clinical relevance is debated- affect HIV control and the role of ART adherence in this relationship. Observational study on the relationship between NCI and viral control during the 2 years before and the 2 after the neurocognitive evaluation (NCE) of 322 PLWH on ART. Viral load (VL) was defined as undetectable, very low-level (VLLV), low-level (LLV), or high-level viremia (HLV), and classified overtime as persistent (p; ≥2 consecutive values in the same worst category), viral failure (VF; ≥1 HLV requiring ART changes), or optimal control. Adherence was the proportion of days covered by ART. Frascati criteria were used. Adjusted models were performed for factors associated with viral control. Mediation analyses informed causality in the path from NCI to viral control through adherence. Sensitivity analyses were focused on the year following NCE for only participants with optimal viral control before. Among the participants (53 ± 10 years, CD4 + T-cells 630/µL), 41.6% and 10.8% presented asymptomatic and symptomatic NCI. Over 3,304 VLs, 8.4% and 22.1% of participants had VF and pLLV/pVLLV. Both symptomatic and asymptomatic NCI were independently associated with VF (aRRR = 8.5; aRRR = 4.3) and pVLLV/pLLV (aRRR = 4.3; aRRR = 2.1). Specific cognitive domains showed independent associations with VL categories (models' P < 0.001). Adherence partially mediated these relationships (models' P < 0.001). Sensitivity analysis confirmed these findings. Prevalence and severity of poor viral control increased as the severity of NCI increased, with ART adherence mediating this relationship. The current "asymptomatic" attribution used by Frascati's criteria could overlook clinical risks.

The presence of resistance‐associated mutations in reverse transcriptase gene is associated with cerebrospinal fluid HIV‐1 escape: A multicentric retrospective analysis

Higher risk of cerebrospinal fluid escape (CVE) has been associated with the use of specific antiretroviral (ARV) classes, such as protease inhibitors. We assessed whether archived resistance-associated mutations (RAMs) can mediate this relationship by identifying patients treated with incompletely active antiretroviral regimens. A retrospective multicentric study on 282 adult people with HIV on antiretroviral therapy (ART) and available historical plasma genotype resistance testing (HGRT) for reverse transcriptase (RT) and protease genes between 2001 and 2021. The odds ratio for demographic, clinic-, and ART-related variables and CVE was estimated by multivariable modeling. HGRT-adjusted central nervous system effectiveness penetration (CPE) score was computed in modeling the risk. Median age, plasma VL, and CD4 count were 49 years, <50 copies/mL, and 310 cells/μL. CVE was detected in 51 participants (17.0%). No difference in CVE prevalence was observed according to ART type, number of ARVs or ARV classes. Participants with CVE had more frequently plasma (52.9% vs. 32.1%, p = 0.005) and CSF RAMs in RT (n = 63, 57.1% vs. 28.6%, p = 0.029), but not in protease gene. The presence of plasma RAMs in RT associated with increased odds of CVE in adjusted analyses (aOR 3.9, p < 0.001) and in models restricted to plasma viral load ≤50 copies/mL (n = 202; aOR 4.3, p = 0.003). CVE risk decreased by 40% per each point increase in HGRT-adjusted CPE score in multivariable models (p < 0.001). Rather than the type of ARV classes or of ART regimens, functional mono or dual regimens caused by the presence of RAMs affecting ART components may explain the majority of cases of CVE.

A Rationale and Approach to the Development of Specific Treatments for HIV Associated Neurocognitive Impairment

Neurocognitive impairment (NCI) associated with HIV infection of the brain impacts a large proportion of people with HIV (PWH) regardless of antiretroviral therapy (ART). While the number of PWH and severe NCI has dropped considerably with the introduction of ART, the sole use of ART is not sufficient to prevent or arrest NCI in many PWH. As the HIV field continues to investigate cure strategies, adjunctive therapies are greatly needed. HIV imaging, cerebrospinal fluid, and pathological studies point to the presence of continual inflammation, and the presence of HIV RNA, DNA, and proteins in the brain despite ART. Clinical trials exploring potential adjunctive therapeutics for the treatment of HIV NCI over the last few decades have had limited success. Ideally, future research and development of novel compounds need to address both the HIV replication and neuroinflammation associated with HIV infection in the brain. Brain mononuclear phagocytes (MPs) are the primary instigators of inflammation and HIV protein expression; therefore, adjunctive treatments that act on MPs, such as immunomodulating agents, look promising. In this review, we will highlight recent developments of innovative therapies and discuss future approaches for HIV NCI treatment.

Shock and kill within the CNS: A promising HIV eradication approach?

The most studied HIV eradication approach is the "shock and kill" strategy, which aims to reactivate the latent reservoir by latency reversing agents (LRAs) and allowing elimination of these cells by immune-mediated clearance or viral cytopathic effects. The CNS is an anatomic compartment in which (persistent) HIV plays an important role in HIV-associated neurocognitive disorder. Restriction of the CNS by the blood-brain barrier is important for maintenance of homeostasis of the CNS microenvironment, which includes CNS-specific cell types, expression of transcription factors, and altered immune surveillance. Within the CNS predominantly myeloid cells such as microglia and perivascular macrophages are thought to be a reservoir of persistent HIV infection. Nevertheless, infection of T cells and astrocytes might also impact HIV infection in the CNS. Genetic adaptation to this microenvironment results in genetically distinct, compartmentalized viral populations with differences in transcription profiles. Because of these differences in transcription profiles, LRAs might have different effects within the CNS as compared with the periphery. Moreover, reactivation of HIV in the brain and elimination of cells within the CNS might be complex and could have detrimental consequences. Finally, independent of activity on latent HIV, LRAs themselves can have adverse neurologic effects. We provide an extensive overview of the current knowledge on compartmentalized (persistent) HIV infection in the CNS and on the "shock and kill" strategy. Subsequently, we reflect on the impact and promise of the "shock and kill" strategy on the elimination of persistent HIV in the CNS.

Risk Factors for CSF/Plasma HIV-1 RNA Discordance in HIV-Infected Patients

BACKGROUND

Few large investigations have evaluated the association of cerebrospinal fluid/plasma (CSF/plasma) discordance with opportunistic neurological infections. We aimed to determine risk factors for CSF/plasma discordance to further assess whether CSF/plasma discordance is associated with antiretroviral therapy (ART) and opportunistic neurological infections.

METHODS

A retrospective study was conducted based on HIV RNA viral load and associated risk factors in plasma and CSF samples from 491 HIV-infected patients. HIV RNA levels higher in CSF compared with plasma was defined as CSF/plasma discordance.

RESULTS

In this study, the rate of CSF/plasma discordance was 18.3%. We observed that headache, cryptococcal antigen, CSF cell count, Treponema pallidum particle assay positivity, and ART use were significantly associated with CSF/plasma discordance in the multivariate logistic regression model. The CSF RNA/plasma RNA ratio was significantly higher in HIV-infected patients with neurological infections than in HIV-infected cases without neurological infections (P < 0.001). CSF/plasma discordance was significantly different between HIV-infected patients without central nervous system (CNS) infection and those with CNS infection, tuberculous meningitis, cryptococcal meningitis, and neurosyphilis (P < 0.05).

CONCLUSIONS

ART and CNS inflammation may influence CSF/plasma discordance.

Neuropathogenesis of HIV-1: insights from across the spectrum of acute through long-term treated infection

This review outlines the neuropathogenesis of HIV, from initial HIV entry into the central nervous system (CNS) to chronic infection, focusing on key advancements in the last 5 years. Discoveries regarding acute HIV infection reveal timing and mechanisms of early HIV entry and replication in the CNS, early inflammatory responses, and establishment of genetically distinct viral reservoirs in the brain. Recent studies additionally explore how chronic HIV infection is maintained in the CNS, examining how the virus remains in a latent "hidden" state in diverse cells in the brain, and how this leads to sustained pathological inflammatory responses. Despite viral suppression with antiretroviral therapy, HIV can persist and even replicate in the CNS, and associate with ongoing neuropathology including CD8 + T-lymphocyte mediated encephalitis. Crucial investigation to advance our understanding of the immune mechanisms that both control viral infection and lead to pathological consequences in the brain is necessary to develop treatments to optimize long-term neurologic health in people living with HIV.

Association of High Ratio of CSF/Plasma HIV-1 RNA with Central Nervous System Co-Infection in HIV-1-Positive Treatment-Naive Patients

Cerebrospinal fluid (CSF) human immunodeficiency virus-1 (HIV-1) ribonucleic acid (RNA) at higher levels than in plasma has been observed in HIV-1-positive patients and defined as CSF/plasma discordance or CSF escape. Discordance is particularly seen in untreated patients with antiretroviral agents. Quantitative data regarding its association with blood−brain barrier (BBB) damage and intracranial co-infection with other pathogens are limited. Therefore, we used the CSF to plasma HIV-1 RNA ratio (HRR) to determine its relation to central nervous system (CNS) co-infection in HIV-1-positive treatment-naïve individuals. We retrospectively recruited the subjects with HIV-1-positive and potential neurological deficits. A lumbar puncture was performed before the antiretroviral therapy. The paired CSF/plasma HIV-1 RNA samples were analyzed. Univariate and multivariate logistic regression models and multiple spine regression analyses were performed to assess the association between the HRR and CNS co-infection. A total of 195 patients with 78% males (median age: 49 years) were included in this study, of whom 98 (50.2%) had CNS co-infection with other pathogens. The receiver-operating characteristic curve analysis showed that the optimal cutoff value for the HRR to predict the CNS co-infection was 1.00. Higher HRR (≥1) was significantly associated with tuberculous meningitis (OR 6.50, 95% CI 2.08−20.25, p = 0.001), cryptococcus meningitis (OR 7.58, 95% CI 2.10−27.32, p = 0.001), and multiple co-infection (OR 4.04, 95% CI 1.02−16.04, p = 0.047). Higher HRR (≥1) (OR 3.01, 95% CI 1.09−8.73, p = 0.032) was independently associated with the CNS co-infection after adjusting for covariates. No significant nonlinear association was found between the HRR and CNS co-infection in the multivariate spline regression (p > 0.05) and a positive relationship was found between the HRR and CNS co-infection when the HRR was ≥0.78. Higher HRR was associated with an increased risk of CNS co-infection in HIV-1-positive patients. The relationship between the HRR and CNS co-infection may be related to the BBB disturbance and warrants further investigation with a large, longitudinal cohort.

Reversal of CSF HIV-1 Escape during Treatment of HIV-Associated Cryptococcal Meningitis in Botswana

Cerebrospinal fluid (CSF) viral escape has been poorly described among people with HIV-associated cryptococcal meningitis. We determined the prevalence of CSF viral escape and HIV-1 viral load (VL) trajectories in individuals treated for HIV-associated cryptococcal meningitis. A retrospective longitudinal study was performed using paired CSF and plasma collected prior to and during the antifungal treatment of 83 participants recruited at the Botswana site of the phase-3 AMBITION-cm trial (2018−2021). HIV-1 RNA levels were quantified then CSF viral escape (CSF HIV-1 RNA ≥ 0.5 log10 higher than plasma) and HIV-1 VL trajectories were assessed. CSF viral escape occurred in 20/62 (32.3%; 95% confidence interval [CI]: 21.9−44.6%), 13/52 (25.0%; 95% CI: 15.2−38.2%) and 1/33 (3.0%; 95% CI: 0.16−15.3%) participants at days 1, 7 and 14 respectively. CSF viral escape was significantly lower on day 14 compared to days 1 and 7, p = 0.003 and p = 0.02, respectively. HIV-1 VL decreased significantly from day 1 to day 14 post antifungal therapy in the CSF but not in the plasma (β = −0.47; 95% CI: −0.69 to −0.25; p < 0.001). CSF viral escape is high among individuals presenting with HIV-associated cryptococcal meningitis; however, antifungal therapy may reverse this, highlighting the importance of rapid initiation of antifungal therapy in these patients.

Management of a human immunodeficiency virus case with discordant antiviral drug resistance profiles in cerebrospinal fluid compared with plasma: a case report

Background

Human immunodeficiency virus-1-associated neurocognitive disorder is a known complication in individuals treated with antiretroviral therapy. Cerebrospinal fluid escape, which is defined as discordant higher cerebrospinal fluid viremia than plasma, may occur in antiretroviral therapy-experienced individuals. Different cerebrospinal fluid versus plasma mutation patterns have been observed in individuals with cerebrospinal fluid escape.

Case presentation

A 46-year-old adult African male with human immunodeficiency virus-1 infection and acquired immunodeficiency syndrome based on cerebral toxoplasmosis and a chronic hepatitis B virus infection developed cerebrospinal fluid escape. A different human immunodeficiency virus-1 genotypic drug resistance profile was observed in plasma compared with cerebrospinal fluid. Brain biopsy and cerebral magnetic resonance imaging indicated the development of human immunodeficiency virus encephalopathy. A discordant protease inhibitor mutation/wild-type T74PT in plasma but not in cerebrospinal fluid indicated poor central nervous system penetration due to the selective pressure of drug therapy. An intensified antiretroviral therapy regimen including dolutegravir with good central nervous system penetration improved conditions.

Conclusions

This case shows the importance of measuring human immunodeficiency virus drug resistance in cerebrospinal fluid, which might differ from resistance detected in plasma samples and target effective antiretroviral therapy treatment accordingly.

Viral capture sequencing detects unexpected viruses in the cerebrospinal fluid of adults with meningitis

OBJECTIVES

Many patients with meningitis have no aetiology identified leading to unnecessary antimicrobials and prolonged hospitalisation. We used viral capture sequencing to identify possible pathogenic viruses in adults with community-acquired meningitis.

METHODS

Cerebrospinal fluid (CSF) from 73 patients was tested by VirCapSeq-VERT, a probe set designed to capture viral targets using high throughput sequencing. Patients were categorised as suspected viral meningitis - CSF pleocytosis, no pathogen identified (n = 38), proven viral meningitis - CSF pleocytosis with a pathogen identified (n = 15) or not meningitis - no CSF pleocytosis (n = 20).

RESULTS

VirCapSeq-VERT detected virus in the CSF of 16/38 (42%) of those with suspected viral meningitis, including twelve individual viruses. A potentially clinically relevant virus was detected in 9/16 (56%). Unexpectedly Toscana virus, rotavirus and Saffold virus were detected and assessed to be potential causative agents.

CONCLUSION

VirCapSeq-VERT increases the probability of detecting a virus. Using this agnostic approach we identified Toscana virus and, for the first time in adults, rotavirus and Saffold virus, as potential causative agents in adult meningitis. Further work is needed to determine the prevalence of atypical viral candidates as well as the clinical impact of using sequencing methods in real time. This knowledge can help to reduce antimicrobial use and hospitalisations leading to both patient and health system benefits.

Improvement of HIV-associated neurocognitive disorders after antiretroviral therapy intensification: the Neuro+3 study

OBJECTIVES

Despite the effectiveness of antiretroviral (ARV) therapy to control HIV infection, HIV-associated neurocognitive disorders (HAND) remain frequent. The Neuro+3 study assessed the cognitive improvement associated with ARV intensification based on increased CNS penetration effectiveness (CPE) scoring ≥+3 and total CPE score ≥9.

METHODS

Thirty-one patients, aged 18-65 years, with confirmed diagnosis of HAND and effective ARV therapy were included. The cognitive improvement was measured using Frascati three-stage classification and global deficit score (GDS) after 48 and 96 weeks of ARV intensification. Ultrasensitive HIV-RNA, neopterin, soluble CD14, CCL2, CXCL10, IL6, IL8 and NF-L were measured in plasma and cerebrospinal fluid at Day 0 (baseline), Week 48 (W48) and W96.

RESULTS

The intensified ARV was associated with a median (IQR) CPE score increase from 6 (4-7) at baseline to 10 (9-11). From baseline to W96, the median (IQR) GDS decreased from 1.4 (0.8-2.2) to 1.0 (0.6-2.0) (P = 0.009); HAND classification improved from 2 to 1 HIV-associated dementia, 22 to 8 mild neurocognitive disorders, 7 to 17 asymptomatic neurocognitive impairment and 0 to 5 patients without any neurocognitive alterations (P = 0.001). In multivariable linear regression analysis, GDS improvement at W96 was significantly associated with CPE score ≥9 after intensification (P = 0.014), CD4 lymphocyte increase at W48 (P < 0.001) and plasma CXCL10 decrease at W96 (P = 0.001).

CONCLUSIONS

In patients with HAND, a significant cognitive improvement was observed after the ARV intensification strategy, with a higher CPE score. Cognitive improvement was more often observed in the case of a switch of two drug classes, arguing for better control of CNS HIV immune activation.

Pharmacokinetics and antiviral activity of cabotegravir and rilpivirine in cerebrospinal fluid following long-acting injectable administration in HIV-infected adults

Background

Long-acting (LA) formulations of cabotegravir, an HIV integrase inhibitor, and rilpivirine, an NNRTI, are in development as monthly or 2 monthly intramuscular (IM) injections for maintenance of virological suppression.

Objectives

To evaluate cabotegravir and rilpivirine CSF distribution and HIV-1 RNA suppression in plasma and CSF in HIV-infected adults participating in a substudy of the Phase 2b LATTE-2 study (NCT02120352).

Methods

Eighteen participants receiving cabotegravir LA 400 mg + rilpivirine LA 600 mg IM [every 4 weeks (Q4W), n = 3] or cabotegravir LA 600 mg + rilpivirine LA 900 mg IM [every 8 weeks (Q8W), n = 15] with plasma HIV-1 RNA <50 copies/mL enrolled. Paired steady-state CSF and plasma concentrations were evaluable in 16 participants obtained 7 (±3) days after an injection visit. HIV-1 RNA in CSF and plasma were assessed contemporaneously using commercial assays.

Results

Median total CSF concentrations in Q4W and Q8W groups, respectively, were 0.011 μg/mL and 0.013 μg/mL for cabotegravir (0.30% and 0.34% of the paired plasma concentrations) and 1.84 ng/mL and 1.67 ng/mL for rilpivirine (1.07% and 1.32% of paired plasma concentrations). Cabotegravir and rilpivirine total CSF concentrations exceeded their respective in vitro EC₅₀ for WT HIV-1 (0.10 ng/mL and 0.27 ng/mL, respectively). All 16 participants had HIV-1 RNA <50 copies/mL in plasma and CSF, and 15 of 16 participants had HIV-1 RNA <2 copies/mL in CSF.

Conclusions

A dual regimen of cabotegravir LA and rilpivirine LA achieved therapeutic concentrations in the CSF resulting in effective virological control in CSF.

Central nervous system (CNS) transcriptomic correlates of human immunodeficiency virus (HIV) brain RNA load in HIV-infected individuals

To generate new mechanistic hypotheses on the pathogenesis and disease progression of neuroHIV and identify novel therapeutic targets to improve neuropsychological function in people with HIV, we investigated host genes and pathway dysregulations associated with brain HIV RNA load in gene expression profiles of the frontal cortex, basal ganglia, and white matter of HIV+ patients. Pathway analyses showed that host genes correlated with HIV expression in all three brain regions were predominantly related to inflammation, neurodegeneration, and bioenergetics. HIV RNA load directly correlated particularly with inflammation genesets representative of cytokine signaling, and this was more prominent in white matter and the basal ganglia. Increases in interferon signaling were correlated with high brain HIV RNA load in the basal ganglia and the white matter although not in the frontal cortex. Brain HIV RNA load was inversely correlated with genesets that are indicative of neuronal and synaptic genes, particularly in the cortex, indicative of synaptic injury and neurodegeneration. Brain HIV RNA load was inversely correlated with genesets that are representative of oxidative phosphorylation, electron transfer, and the tricarboxylic acid cycle in all three brain regions. Mitochondrial dysfunction has been implicated in the toxicity of some antiretrovirals, and these results indicate that mitochondrial dysfunction is also associated with productive HIV infection. Genes and pathways correlated with brain HIV RNA load suggest potential therapeutic targets to ameliorate neuropsychological functioning in people living with HIV.

Dual antiretroviral therapies are effective and safe regimens in the central nervous system of neurologically symptomatic people living with HIV

OBJECTIVE

Aim of this study was to compare cerebrospinal fluid (CSF) virological control, biomarkers and neurocognition of neurologically symptomatic patients on dual antiretroviral therapies (dual therapy) vs. 2 nucleoside reverse transcriptase inhibitors-based three-drug regimens (triple therapy).

DESIGN

Retrospective monocentric cross-sectional study.

METHODS

We analysed data from people living with HIV undergoing lumbar puncture for clinical/research reasons with plasma HIV-RNA less than 200 copies/ml and neurological/neurocognitive symptoms without significant contributing comorbidities. We measured CSF HIV-RNA, inflammation, blood-brain barrier integrity, neuronal damage and astrocytosis biomarkers (five biomarkers by ELISA and five indices by immunoturbidimetry) and recorded the neurocognitive performance (14 tests). CSF escape was defined as any case of CSF HIV-RNA 0.5 Log10 higher than viraemia or any case of detectable CSF HIV-RNA coupled with undetectable viraemia.

RESULTS

A total of 78 patients on triple therapy and 19 on dual therapy were included. Overall, 75.3% male, median age 51 years (46-58), current CD4 count 545 cells/μl (349-735), time on current regimens 18 months (8-29), but length of plasma suppression 32 months (14-94). The two groups did not differ in terms of HIV-associated neurological diagnoses, demographic and viro-immunological features. Undetectable CSF HIV-RNA (73.7% in dual therapy vs. 78.2% in triple therapy, p.67) and CSF escape (21.1% in dual therapy vs. 19.2% in triple therapy, p.86) did not differ. No difference was observed in depression, anxiety, neurocognition (in 63 participants) nor in any tested biomarker.

CONCLUSION

In people living with HIV with neurological/neurocognitive symptoms, peripherally effective dual therapy can show CSF virosuppression, inflammation, neuronal and astrocyte integrity and neurocognition comparable to triple therapy.

A rare case of HIV CNS escape in a patient previously considered a viral controller

Human immunodeficiency virus (HIV) ribonucleic acid (RNA) levels generally remain undetectable in the cerebrospinal fluid of people living with HIV with peripheral viral suppression. Secondary HIV central nervous system (CNS) escape refers to the rare independent replication of HIV RNA in the central nervous system despite peripheral viral suppression that occurs in the setting of a concomitant non-HIV infection. We describe here a young man with perinatal HIV infection considered a viral controller who developed secondary HIV CNS escape in the setting of a presumed fungal CNS infection.

Differences in human immunodeficiency virus-1C viral load and drug resistance mutation between plasma and cerebrospinal fluid in patients with human immunodeficiency virus-associated cryptococcal meningitis in Botswana

To determine effects of cryptococcal meningitis (CM) on human immunodeficiency virus (HIV)-1C cerebrospinal fluid (CSF) viral escape, CSF/plasma viral discordance, and drug resistance mutation (DRM) discordance between CSF and plasma compartments, we compared CSF and plasma viral load (VL) and DRMs in individuals with HIV-associated CM in Botswana.This cross-sectional study utilized 45 paired CSF/plasma samples from participants in a CM treatment trial (2014-2016). HIV-1 VL was determined and HIV-1 protease and reverse transcriptase genotyping performed. DRMs were determined using the Stanford HIV database. CSF viral escape was defined as HIV-1 ribonucleic acid ≥0.5 log10 higher in CSF than plasma and VL discordance as CSF VL > plasma VL.HIV-1 VL was successfully measured in 39/45 pairs, with insufficient sample volume in 6; 34/39 (87.2%) participants had detectable HIV-1 in plasma and CSF, median 5.1 (interquartile range: 4.7-5.7) and 4.6 (interquartile range:3.7-4.9) log10 copies/mL, respectively (P≤.001). CSF viral escape was present in 1/34 (2.9%) and VL discordance in 6/34 (17.6%). Discordance was not associated with CD4 count, antiretroviral status, fungal burden, CSF lymphocyte percentage nor mental status. Twenty-six of 45 (57.8%) CSF/plasma pairs were successfully sequenced. HIV-1 DRM discordance was found in 3/26 (11.5%); 1 had I84IT and another had M46MI in CSF only. The third had K101E in plasma and V106 M in CSF.Our findings suggest that HIV-1 escape and DRM discordance may occur at lower rates in participants with advanced HIV-disease and CM compared to those with HIV associated neurocognitive impairment.

Human Immunodeficiency Virus Type 1 RNA Detected in the Central Nervous System (CNS) After Years of Suppressive Antiretroviral Therapy Can Originate from a Replicating CNS Reservoir or Clonally Expanded Cells

BACKGROUND

Human immunodeficiency virus type 1 (HIV-1) populations are detected in cerebrospinal fluid (CSF) of some people on suppressive antiretroviral therapy (ART). Detailed analysis of these populations may reveal whether they are produced by central nervous system (CNS) reservoirs.

METHODS

We performed a study of 101 asymptomatic participants on stable ART. HIV-1 RNA concentrations were cross-sectionally measured in CSF and plasma. In participants with CSF HIV-1 RNA concentrations sufficient for analysis, viral populations were genetically and phenotypically characterized over multiple time points.

RESULTS

For 6% of participants (6 of 101), the concentration of HIV-1 RNA in their CSF was ≥0.5 log copies/mL above that of plasma (ie, CSF escape). We generated viral envelope sequences from CSF of 3 participants. One had a persistent CSF escape population that was macrophage-tropic, partially drug resistant, genetically diverse, and closely related to a minor macrophage-tropic lineage present in the blood prior to viral suppression and enriched for after ART. Two participants (1 suppressed and 1 not) had transient CSF escape populations that were R5 T cell-tropic with little genetic diversity.

CONCLUSIONS

Extensive analysis of viral populations in 1 participant revealed that CSF escape was from a persistently replicating population, likely in macrophages/microglia, present in the CNS over 3 years of ART. CSF escape in 2 other participants was likely produced by trafficking and transient expansion of infected T cells in the CNS. Our results show that CNS reservoirs can persist during ART and that CSF escape is not exclusively produced by replicating CNS reservoirs.

Two treatment strategies for management of Neurosymptomatic cerebrospinal fluid HIV escape in Pune, India

Symptomatic cerebrospinal fluid (CSF) viral escape (sCVE) is reported in people with HIV, who are on ritonavir-boosted protease inhibitor (PI/r) containing antiretroviral therapy (ART). Management of sCVE includes performing genotypic HIV-1 resistance testing (GRT) on CSF and plasma HIV and changing ART accordingly. Neither GRT nor newer drugs (Dolutegravir and Darunavir/ritonavir) are routinely available in India. As a result, management of sCVE includes 2 modalities: a) ART intensification by adding drugs that reach therapeutic concentrations in CSF, like Zidovudine, to existing ART or b) Changing to a regimen containing newer boosted PI/r and integrase strand transfer inhibitor (INSTI) as per GRT or expert opinion. In this retrospective study, we report the outcomes of above 2 modalities in treatment of sCVE in Pune, India.Fifty-seven episodes of sCVE in 54 people with HIV taking PI/r-containing ART were identified. Clinical, demographic, laboratory and ART data were recorded. Forty-seven cases had follow-up data available after ART change including measurement of plasma and CSF viral load (VL).Of the 47 cases, 23 received zidovudine intensification (Group A, median VL: plasma- 290, CSF- 5200 copies/mL) and 24 received PI/INSTI intensification (Group B, median VL: plasma- 265, CSF-4750 copies/mL). CSF GRT was performed in 16 participants: 8 had triple class resistance. After ART change, complete resolution of neurologic symptoms occurred in most participants (Group A: 18, Group B: 17). In Group A, follow-up plasma and CSF VL were available for 21 participants, most of whom achieved virologic suppression (VL < 20 copies/mL) in plasma (17) and CSF (15). Four participants were shifted to the PI/INSTI intensification group due to virologic failure (plasma or CSF VL > 200 copies/mL). In Group B, follow-up plasma and CSF VL were available for 23 participants, most of whom also achieved virologic suppression in plasma (21) and CSF (18). Four deaths were noted, 2 of which were in individuals who interrupted ART.This is a unique sCVE cohort that was managed with 1 of 2 approaches based on treatment history and the availability of GRT. At least 75% of participants responded to either approach with virologic suppression and improvement in symptoms.

HIV-1 Central Nervous System Compartmentalization and Cytokine Interplay in Non-Subtype B HIV-1 Infections in Nigeria and Malawi

HIV-1 compartmentalization in the central nervous system (CNS) and its contribution to neurological disease have been well documented. Previous studies were conducted among people infected with subtypes B or C where CNS compartmentalization has been observed when comparing viral sequences in the blood to virus in cerebrospinal fluid (CSF). However, little is known about CNS compartmentalization in other HIV-1 subtypes. Using a deep sequencing approach with Primer ID, we conducted a cross-sectional study among Nigerian and Malawian HIV-1 cohorts with or without fungal Cryptococcus infection diagnosed as cryptococcal meningitis (CM) to determine the extent of CSF/CNS compartmentalization with CM. Paired plasma and CSF samples from 45 participants were also analyzed for cytokine/chemokine levels. Viral populations comparing virus in the blood and the CSF ranged from compartmentalized to equilibrated, including minor or partial compartmentalization or clonal amplification of a single viral sequence. The frequency of compartmentalized viral populations in the blood and CSF was similar between the CM- and CM+ participants. We confirmed the potential to see compartmentalization with subtype C infection and have also documented CNS compartmentalization of an HIV-1 subtype G infection. Cytokine profiles indicated a proinflammatory environment, especially within the CSF/CNS. However, sCD163 was suppressed in the CSF in the presence of CM, perhaps due to elevated levels of IL-4, which were also a feature of the cytokine profile, showing a distinct cytokine profile with CM.

Cerebrospinal fluid pleocytosis as a predictive factor for CSF and plasma HIV RNA discordance and escape

The aims of this study were to investigate the frequency of HIV-1 RNA level discordance between the cerebrospinal fluid (CSF) and plasma and of CSF viral escape (CVE) in patients with HIV-1 subtype C on antiretroviral therapy, and evaluate the CSF white blood cell (WBC) performance characteristics in predicting CSF discordance in HIV+ group and the frequency of cognitive impairment in individuals with CSF HIV discordance or escape. HIV-1 RNA levels were assessed in plasma and CSF samples from 68 HIV+ participants without opportunistic infection. CSF discordance was found in 7.4% and CVE in 10%, with comparable frequencies between HIV-1B and C. Twenty samples (29%) showed increased CSF WBC counts. This group had higher CSF and plasma HIV-1 RNA levels than the group with normal WBC counts (p < 0.0001 and 0.006, respectively). The odds of CSF discordance were 18 times higher for a person with CSF WBC count of > 5 cells/mm3 than the group with normal CSF WBC count. CSF WBC counts (cut-off of 15 cells/mm3) showed high-performance characteristics as a predictive biomarker of CSF discordance (AUC the ROC curve 0.98). The frequency of cognitive impairment for CSF escape or discordance was 83% and 80%. The odds of cognitive impairment in these groups were 19 and 15 times higher than those for an HIV(-) person. Viral discordance or escape in the CNS occurs at a comparable frequency for HIV-1C and HIV-1B. The CSF WBC count was effective as a predictive biomarker of CSF and plasma discordance.

What can characterization of cerebrospinal fluid escape populations teach us about viral reservoirs in the central nervous system?

OBJECTIVE

To review the evidence that CSF (cerebrospinal fluid) escape populations are produced by viral reservoirs in the central nervous system (CNS).

DESIGN

CSF escape is a rare phenomenon in which individuals on suppressive ART have well controlled systemic infections with elevated levels of HIV-1 RNA in their CSF. However, the rarity of CSF escape coupled with relatively low CSF viral loads has impeded detailed analyses of these populations. Here, and in a previous study, we performed genetic and phenotypic assessments of CSF escape populations to determine whether CSF escape is produced by CNS reservoirs or by cells trafficking through the CNS.

METHODS

We report HIV-1 viral loads in the CSF and blood plasma of four individuals with CSF escape (one new example and three previously described examples). We performed phylogenetic analyses of the viral env gene to evaluate diversity within the CSF escape populations and performed entry analyses to determine whether Env proteins were adapted to entering macrophage/microglia.

RESULTS

Two individuals had CSF escape produced by CNS reservoirs. In contrast, the remaining two cases were likely because of transient viral production from cells migrating into the CNS and releasing virus.

CONCLUSION

Together our analyses indicate that replication-competent HIV-1 can persist in the CNS during ART, but that not all cases of CSF escape are produced by CNS reservoirs. Our results also suggest that both CD4 T cells and macrophage/microglia can serve as persistent viral reservoirs in the CNS.

Symptomatic cerebrospinal fluid escape

: Cerebrospinal fluid (CSF) viral escape is defined by detectable HIV-RNA in CSF despite undetectable or lower-than-CSF level in plasma of patients receiving combination antiretroviral therapy (cART). This condition may occasionally be associated with neurological problems, consisting of new and progressive cognitive decline and/or focal symptoms and signs, defining the 'symptomatic CSF escape'. Brain MRI usually shows diffuse white matter hyperintensities that recall the presentation of HIV encephalopathy in the precART era. However, patients develop symptomatic CSF escape with relatively high CD4 cell counts and suppressed or low systemic virus replication. In addition, the frequent CSF pleocytosis and the pathological demonstration of CD8 T-cell brain infiltrates in some cases of symptomatic escape indicate that inflammation is an important component in the pathogenesis of this condition. Low nadir CD4 cells are common, likely reflecting the establishment of a HIV reservoir in the central nervous system (CNS). CSF escape seems to result from reactivation of CNS infection when cART potency is lowered, because of low patient's adherence, drug resistance, or use of drug combinations that are poorly effective in the CNS and cART optimization is key to revert escape and neurological disease in the great majority of cases.

HIV-1 persistence in the central nervous system: viral and host determinants during antiretroviral therapy

Despite remarkable therapeutic advances in the past two decades, the elimination of human immunodeficiency virus type 1 (HIV-1) from latent reservoirs constitutes a major barrier to eradication and preventing neurological disease associated with HIV/AIDS. Invasion of the central nervous system (CNS) by HIV-1 occurs early in infection, leading to viral infection and productive persistence in brain macrophage-like cells (BMCs) including resident microglia and infiltrating macrophages. HIV-1 persistence in the brain and chronic neuroinflammation occur despite effective treatment with antiretroviral therapy (ART). This review examines the evidence from clinical studies, in vivo and in vitro models for HIV-1 CNS persistence, as well as therapeutic considerations in targeting latent CNS reservoirs.

CNS-Targeted Antiretroviral Strategies: When Are They Needed and What to Choose

PURPOSE OF REVIEW

Neurocognitive disorders are not uncommon in HIV-positive patients but their pathogenesis is multifactorial and incompletely understood. After excluding contributing comorbidities, several factors may impair neurocognition including severe immune suppression, incomplete antiviral efficacy, drugs' persistent immune activation, vascular abnormalities, and drugs' neurotoxicity. The effectiveness of targeted antiretroviral strategies on these risk factors is unknown.

RECENT FINDINGS

Recent studies support the idea that residual cerebrospinal fluid HIV RNA in the setting of plasma viral suppression is associated with compartmental immune activation but the link to neuronal damage is debated. Some authors have reported an incomplete antiviral efficacy in macrophage-derived cells but targeted antiretroviral regimen switches have not been performed. Additionally, improvements in neurocognition using drugs with better central nervous system penetration or maraviroc (associated with favorable immunological properties) have been observed in pilot studies. Trials evaluating specific interventions for cardiovascular health (including brain white matter abnormalities) and neurotoxicity of antiretrovirals are warranted. Central nervous system-targeted antiretroviral strategies are needed in patients with uncontrolled cerebrospinal HIV replication, and they may be suggested in subjects with low CD4 nadir, individuals carrying drug-resistant viruses, and those with compartmental immune activation.

Cerebrospinal fluid compartmentalization of HIV-1 and correlation with plasma viral load and blood-brain barrier damage

PURPOSE

We aimed to evaluate HIV-1 compartmentalization between the cerebrospinal fluid (CSF) and plasma and investigate as to which extent HIV-1 strains in CSF differ from those in blood and whether a correlation with either plasma viral load (pVL) or an altered blood-brain barrier (BBB) does exist.

STUDY DESIGN

We retrospectively evaluated paired CSF/blood samples collected from 86 HIV+ patients. HIV-RNA quantification, pol (PR/RT), and V3 sequencing were performed. HIV coreceptor tropism (CRT) was inferred (g2p, false-positive rate 10%, FPR). Data of standard CSF analysis were also reviewed; an altered CSF/plasma albumin ratio signified BBB damage. Neurological abnormalities (NA) were recorded.

RESULTS

Overall, 32% of patients had a CSF/plasma HIV-RNA ratio > 1 (discordance); 3% of patients had detectable CSF HIV-RNA despite suppressed pVL (escape). Discordance was more frequent in ART-treated patients (p < 0.001) and in patients with NA (p = 0.016), but was independent of BBB damage (p = 0.65) and AIDS diagnosis (p = 0.96). Finally, CSF/plasma discordance was significantly more frequent (p < 0.0001) in patients with lower pVL values (< 10.000 copies/ml). Env divergence > 10% was found in 44% of sequences and was associated with ART (p = 0.008) and NA (p = 0.037). Overall, 24% of patients had a discordant CSF/blood CRT. A 100% nucleotide identity was observed in only 7.3% of pol sequences; notably, 10% of patients had resistance-associated mutations in CSF, but not in blood.

CONCLUSIONS

Our data confirm an independent replication and evolution of HIV within the CSF. A number of factors either hinder or contribute to the compartmentalization of HIV.

HIV Cerebrospinal Fluid Escape and Neurocognitive Pathology in the Era of Combined Antiretroviral Therapy: What Lies Beneath the Tip of the Iceberg in Sub-Saharan Africa?

Neurocognitive impairment remains an important HIV-associated comorbidity despite combination antiretroviral therapy (ART). Since the advent of ART, the spectrum of HIV-associated neurocognitive disorder (HAND) has shifted from the most severe form to milder forms. Independent replication of HIV in the central nervous system despite ART, so-called cerebrospinal fluid (CSF) escape is now recognised in the context of individuals with a reconstituted immune system. This review describes the global prevalence and clinical spectrum of CSF escape, it role in the pathogenesis of HAND and current advances in the diagnosis and management. It highlights gaps in knowledge in sub-Saharan Africa where the HIV burden is greatest and discusses the implications for this region in the context of the global HIV treatment scale up.

Impact of Antiretroviral Regimens on Cerebrospinal Fluid Viral Escape in a Prospective Multicohort Study of Antiretroviral Therapy-Experienced Human Immunodeficiency Virus-1-Infected Adults in the United States

Background

Cerebrospinal fluid (CSF) viral escape occurs in 4%-20% of human immunodeficiency virus (HIV)-infected adults, yet the impact of antiretroviral therapy (ART) on CSF escape is unclear.

Methods

A prospective study of 1063 participants with baseline plasma viral load (VL) ≤400 copies/mL between 2005 and 2016. The odds ratio (OR) for ART regimens (protease inhibitor with nucleoside reverse transcriptase inhibitor [PI + NRTI] vs other ART) and CSF escape was estimated using mixed-effects models.

Results

Baseline mean age was 46 years, median plasma VL, and CD4 count were 50 copies/mL, and 424 cells/μL, respectively. During median follow-up of 4.4 years, CSF escape occurred in 77 participants (7.2%). PI + NRTI use was an independent predictor of CSF escape (OR, 3.1; 95% confidence interval, 1.8-5.0) in adjusted analyses and models restricted to plasma VL ≤50 copies/mL (P < .001). Regimens that contained atazanavir (ATV) were a stronger predictor of CSF viral escape than non-ATV PI + NRTI regimens. Plasma and CSF M184V/I combined with thymidine-analog mutations were more frequent in CSF escape vs no escape (23% vs 2.3%). Genotypic susceptibility score-adjusted central nervous system (CNS) penetration-effectiveness (CPE) values were calculated for CSF escape with M184V/I mutations (n = 34). Adjusted CPE values were low (<5) for CSF in 27 (79%), indicating suboptimal CNS drug availability.

Conclusions

PI + NRTI regimens are independent predictors of CSF escape in HIV-infected adults. Reduced CNS ART bioavailability may predispose to CSF escape in patients with M184V/I mutations.

Incidence of symptomatic CSF viral escape in HIV infected patients receiving atazanavir/ritonavir (ATV/r)-containing ART: a tertiary care cohort in western India

This single-center study attempts to quantify the incidence of symptomatic CSF viral escape (CSFVE) in patients receiving atazanavir/r (ATV/r)-containing regimen. We performed a retrospective analysis of patients receiving ATV/r-containing ART who were diagnosed with symptomatic CSFVE from August 2012 to January 2017. Primary objective was to assess the incidence of symptomatic CSFVE in patients receiving ATV/r-containing ART in clinical practice. Incidence rates were calculated by dividing the number of patients who experienced CSFVE by the number of person-months at risk and summarized as per 10,000 (ten thousand) person-months at risk. Nine hundred thirty-three patients receiving ATV/r containing ART with a total of 36,068 person-months of follow-up were included. Incidence rate of symptomatic CSFVE was 4.4 per 10,000 person-months (95% CI 2.7 to 7.2). The incidence of CSFVE was 9.5 per 10,000 person-months (95% CI 5.7 to 15.7) when the nadir CD4 count was ≤ 200 compared to 0.49 (95% CI 0.07 to 3.5) with a nadir CD4 count > 200 (IRR 19.1 (95% CI 2.93 to 802.8), p < 0.0001). Nadir CD4 count ≤ 200 was associated with substantially increased risk of symptomatic CSFVE, further strengthening efforts to diagnose and treat patients early in disease.

Factors Associated With Persistence of Plasma HIV-1 RNA During Long-term Continuously Suppressive Firstline Antiretroviral Therapy

Background

Persistence of plasma HIV-1 RNA during seemingly effective antiretroviral thereapy (ART) is incompletely understood. Using an ultrasensitive assay, this cross-sectional study investigated residual plasma HIV-1 RNA in subjects maintained on firstline ART with continuous viral load suppression <50 copies/mL for ≤15 years without recognized viral load blips or treatment interruptions and explored its relationship with the duration of suppressive ART, efavirenz concentrations in plasma, 2-LTR circular HIV-1 DNA (2-LTRc DNA) in peripheral blood mononuclear cells, and cellular (CD4 plus CD26/CD38/CD69; CD8 plus CD38/HLA-DR/DP/DQ) and soluble (sCD14, sCD27, sCD30, IL-6) markers of immune activation in peripheral blood.

Methods

Residual plasma HIV-1 RNA, total HIV-1 DNA and 2-LTRc DNA were quantified by real-time and digital droplet PCR. Cellular (CD4 plus CD26/CD38/CD69; CD8 plus CD38/HLA-DR/DP/DQ) and soluble (sCD14, sCD27, sCD30, IL-6) markers of immune activation were measured by flow cytometry and ELISA.

Results

Residual plasma HIV-1 RNA and 2-LTRc DNA were detected in 52/104 (50%) and 24/104 (23%) subjects, respectively. Among subjects with detectable HIV-1 RNA, 50/52 showed levels ≤11 copies/mL. In adjusted analyses, HIV-1 RNA levels were 0.37 log₁₀ copies/mL higher with each log₁₀ U/mL increase in sCD27 (95% confidence interval, 0.01-0.73; P = .02). No significant association was found between residual plasma HIV-1 RNA and other explored parameters.

Conclusions

These findings point to an ongoing relationship between plasma HIV-1 RNA and selected markers of immune activation during continuously suppressive ART. The novel direct association with levels of sCD27 warrants further investigation.

Discordant CSF/plasma HIV-1 RNA in individuals on virologically suppressive antiretroviral therapy in Western India

Aim of this study was to estimate the prevalence of cerebrospinal fluid (CSF)/Plasma HIV-1 RNA discordance in virologically suppressed individuals presenting with incident neurologic symptoms.In this retrospective cohort study conducted between March 1, 2009, and March 1, 2017, HIV-1 infected adults exposed to atleast 12 months of antiretroviral therapy (ART) and having plasma viral load (VL) <1000 copies/mL (virologically suppressed) were included. Among these, individuals presenting with neurologic symptoms during follow-up were assessed for CSF/Plasma HIV-1 RNA discordance by measuring HIV-1 RNA in collected plasma and CSF samples. CSF/plasma HIV-1 RNA discordance was defined as either detectable CSF HIV-1 RNA (VL > 20 copies/mL) with an undetectable plasma RNA (complete viral suppression, VL ≤20 copies/mL) or CSF HIV-1 RNA ≥ 0.5 log10 higher than plasma RNA when plasma VL was between 20 and 1000 copies/mL (low-level viremia, LLV).Out of 1584 virologically suppressed patients, 71 (4.4%) presented with incident neurologic symptoms. Twenty out of 71 (28.2%) patients were diagnosed with CSF/Plasma HIV-1 discordance. Median plasma and CSF VL in patients with discordance was 120 [interquartile range (IQR): <20 to 332.5] and 4250 (IQR: 2550.0- 9615.0) copies/mL, respectively. All 9 individuals in which CSF HIV-1 genotypic resistance testing was done showed mutations that would compromise efficacy of prescribed ART regimen. Prevalence of CSF/plasma HIV-1 RNA discordance was higher among neurologically symptomatic patients with plasma LLV as compared with those with complete viral suppression (70% vs 11.8%, P < .001). The risk of discordance was also greater in patients who received protease inhibitor (PI) containing ART (P < .001) and those on ART regimens with central nervous system (CNS) penetration effectiveness (CPE) value <6 (P = .006).CSF/plasma HIV-1 RNA discordance indicates replication of HIV-1 that has adapted to the CNS or has developed antiretroviral drug resistance. Larger studies should be performed to study incidence of discordance in India. This will help in managing patients presenting with neurologic symptoms on suppressive ART with appropriate neuroeffective therapy.

Symptomatic cerebrospinal fluid HIV-1 escape with no resistance-associated mutations following low-level plasma viremia

The majority of neurologically symptomatic cerebrospinal fluid HIV-1 escape cases are connected with resistance-associated mutations and potentially explained by low cerebrospinal fluid antiretroviral concentrations. However, there are still significant knowledge gaps regarding the physiopathology and long-term management of neurosymptomatic viral escape. We report a case of Parkinson-like syndrome following cerebrospinal fluid HIV-1 escape in a 40-year-old female patient with an history of persistent low-level plasma viremia under treatment. No resistance-associated mutations, high viral diversity (env deep sequencing), adequate pharmacokinetics, atypical CD3-CD14-CD4+CD5-CD2-/+CD7-/+ lymphocytes, low-level Epstein-Barr virus replication, and white matter autoimmune reactivity were observed in the cerebrospinal fluid. Antiretroviral regimen modification led to rapid clinical and radiological improvements. This case may increase the current uncertain knowledge on the origin of cerebrospinal fluid HIV-1 and illustrates the consequences of uncontrolled compartmental viral replication; it also highlights the relevance and persistence of immune activation and the possibility of various detrimental mechanisms underlying neurosymptomatic viral escape.

Temporal Patterns and Drug Resistance in CSF Viral Escape Among ART-Experienced HIV-1 Infected Adults

Supplemental Digital Content is Available in the Text.

Background:

Cerebrospinal fluid (CSF) viral escape is an increasingly recognized clinical event among HIV-1-infected adults. We analyzed longitudinal data and drug-resistance mutations to characterize profiles of HIV-1-infected patients on antiretroviral therapy with discordant CSF and plasma HIV-1 RNA levels.

Methods:

Forty-one cases of CSF escape defined as detectable CSF HIV-1 RNA when plasma levels were undetectable, or HIV-1 RNA >0.5-log higher in CSF than plasma were identified from Boston Hospitals and National NeuroAIDS Tissue Consortium (NNTC) from 2005 to 2016.

Results:

Estimated prevalence of CSF escape in Boston and NNTC cohorts was 6.0% and 6.8%, respectively; median age was 50, duration of HIV-1 infection 17 years, CD4 count 329 cells/mm³ and CD4 nadir 21 cells/mm³. Neurological symptoms were present in 30 cases; 4 had repeat episodes of CSF escape. Cases were classified into subtypes based plasma HIV-1 RNA levels in the preceding 24 months: high-level viremia (1000 copies/mL), low-level viremia (LLV: 51–999 copies/mL), and plasma suppression with CSF blip or escape (CSF RNA <200 or ≥200 copies/mL). High-level viremia cases reported more substance abuse, whereas LLV or plasma suppression cases were more neurosymptomatic (81% vs. 53%); 75% of repeat CSF escape cases were classified LLV. M184V/I mutations were identified in 74% of CSF samples when plasma levels were ≤50 copies per milliliter.

Conclusions:

Characteristics frequently observed in CSF escape include HIV-1 infection >15 years, previous LLV, and M184V/I mutations in CSF. Classification based on preceding plasma HIV RNA levels provides a useful conceptual framework to identify causal factors and test therapeutics.

Diffuse White Matter Signal Abnormalities on Magnetic Resonance Imaging Are Associated With Human Immunodeficiency Virus Type 1 Viral Escape in the Central Nervous System Among Patients With Neurological Symptoms

Background.

Human immunodeficiency virus type 1 (HIV-1) can replicate independently in extravascular compartments such as the central nervous system, resulting in either cerebrospinal fluid (CSF) discordance (viral load [VL] in CSF 0.5 log₁₀ copies HIV-1 RNA greater than plasma VL) or escape (detection of HIV VL >50 copies/mL in CSF in patients with suppressed plasma VL <50 copies/mL). Both discordance and escape may be associated with neurological symptoms. We explored risk factors for CSF discordance and escape in patients presenting with diverse neurological problems.

Methods.

HIV-infected adult patients undergoing diagnostic lumbar puncture (LP) at a single center between 2011 and 2015 were included in the analysis. Clinical and neuroimaging variables associated with CSF discordance/escape were identified using multivariate logistic regression.

Results.

One hundred forty-six patients with a median age of 45.3 (interquartile range [IQR], 39.6–51.5) years underwent 163 LPs. Median CD4 count was 430 (IQR, 190–620) cells/µL. Twenty-four (14.7%) LPs in 22 patients showed CSF discordance, of which 10 (6.1%) LPs in 9 patients represented CSF escape. In multivariate analysis, both CSF discordance and escape were associated with diffuse white matter signal abnormalities (DWMSAs) on cranial magnetic resonance imaging (adjusted odds ratio, 10.3 [95% confidence interval {CI}, 2.3–45.0], P = .007 and 56.9 [95% CI, 4.0–882.8], P = .01, respectively). All 7 patients with CSF escape (10 LPs) had been diagnosed with HIV >7 years prior to LP, and 6 of 6 patients with resistance data had documented evidence of drug-resistant virus in plasma.

Conclusions.

Among patients presenting with diverse neurological problems, CSF discordance or escape was observed in 15%, with treatment-experienced patients dominating the escape group. DWMSAs in HIV-infected individuals presenting with neurological problems should raise suspicion of possible CSF discordance/escape.

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.

The Role of HIV Infection in Neurologic Injury

The central nervous system (CNS) is a very challenging HIV-1 sanctuary, in which HIV-1 replication is established early on during acute infection and can persist despite potent antiretroviral treatments. HIV-1 infected macrophages play a pivotal role acting as vehicles for HIV-1 to spread into the brain, and can be the major contributor of an early compartmentalization. HIV-1 infection in CNS may lead to a broad spectrum of neurological syndromes, such as dementia, mild neurocognitive disorders, and asymptomatic impairment. These clinical manifestations are caused by the release of neurotoxins from infected cells (mainly macrophages), and also by several HIV-1 proteins, able to activate cell-signaling involved in the control of cellular survival and apoptosis. This review is aimed at highlighting the virological aspects associated with the onset of neurocognitive disorders and at addressing the novel therapeutic approaches to stop HIV-1 replication in this critical sanctuary.

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.

Highlights of the Global HIV-1 CSF Escape Consortium Meeting, 9 June 2016, Bethesda, MD, USA

CSF HIV escape is a recently recognised phenomenon that suggests that despite suppressive treatment, HIV RNA may be detected in the CNS compartment in some individuals. In rare cases this is associated with clinical neurological disease, while in most cases, neurological consequences are not apparent. Attempts at characterising the biological substrates of CSF escape and further investigating the neurological consequences need to be made to better understand the implications of this condition for the HIV cure agenda as well as for clinical outcomes. The Global CSF HIV-1 Escape Consortium meeting, convened by the US National Institute of Mental Health, was a first step to gather investigators from diverse sites to discuss opportunities for future collaborative work on this emerging issue. To better understand CSF HIV escape and allow cross-site data reconciliation, it will be useful to reach a consensus set of definitions of the distinct forms of CSF escape, without which concerted cross-site efforts are difficult.

Efavirenz and Metabolites in Cerebrospinal Fluid: Relationship with CYP2B6 c.516G→T Genotype and Perturbed Blood-Brain Barrier Due to Tuberculous Meningitis

Efavirenz (EFZ) has been associated with neuropsychiatric side effects. Recently, the 8-hydroxy-EFZ (8OH-EFZ) metabolite has been shown to be a potent neurotoxin in vitro, inducing neuronal damage at concentrations of 3.3 ng/ml. EFZ induced similar neuronal damage at concentrations of 31.6 ng/ml. We investigated the effect of genotype and blood-brain barrier integrity on EFZ metabolite concentrations in cerebrospinal fluid (CSF). We measured CSF drug concentrations in subjects from two separate study populations: 47 subjects with tuberculous meningitis (TBM) coinfection in Vietnam receiving 800 mg EFZ with standard antituberculous treatment and 25 subjects from the PARTITION study in the United Kingdom without central nervous system infection receiving 600 mg EFZ. EFZ and metabolite concentrations in CSF and plasma were measured and compared with estimates of effectiveness and neurotoxicity from available published in vitro and in vivo data. The effect of the CYP2B6 c.516G→T genotype (GG genotype, fast EFV metabolizer status; GT genotype, intermediate EFV metabolizer status; TT genotype, slow EFV metabolizer status) was examined. The mean CSF concentrations of EFZ and 8OH-EFZ in the TBM group were 60.3 and 39.3 ng/ml, respectively, and those in the no-TBM group were 15.0 and 5.9 ng/ml, respectively. Plasma EFZ and 8OH-EFZ concentrations were similar between the two groups. CSF EFZ concentrations were above the in vitro toxic concentration in 76% of samples (GG genotype, 61%; GT genotype, 90%; TT genotype, 100%) in the TBM group and 13% of samples (GG genotype, 0%; GT genotype, 18%; TT genotype, 50%) in the no-TBM group. CSF 8OH-EFZ concentrations were above the in vitro toxic concentration in 98% of the TBM group and 87% of the no-TBM group; levels were independent of genotype but correlated with the CSF/plasma albumin ratio. Potentially neurotoxic concentrations of 8OH-EFZ are frequently observed in CSF independently of the CYP2B6 genotype, particularly in those with impaired blood-brain barrier integrity.

CSF/plasma HIV-1 RNA discordance even at low levels is associated with up-regulation of host inflammatory mediators in CSF

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Discordant HIV in CSF is associated with raised inflammatory mediators in CSF.

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CSF mediators are raised with discordance both at high and low levels.

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Discordance on ultrasensitive testing can also be also associated with raised mediators.

Introduction

HIV-1 RNA can be found at higher levels in cerebrospinal fluid (CSF) than in plasma, termed CSF/plasma discordance. The clinical significance of CSF/plasma discordance is not known and the degree of discordance considered important varies. We aimed to determine whether a panel of CSF cytokines, chemokines and associated mediators were raised in patients with CSF/plasma discordance at different levels.

Methods

A nested case-control study of 40 CSF samples from the PARTITION study. We used a cytometric bead array to measure CSF mediator concentrations in 19 discordant and 21 non-discordant samples matched for plasma HIV-1 RNA. Discordant samples were subdivided into ‘high discordance’ (>1log₁₀) and ‘low discordance’ (0.5–1log₁₀, or ultrasensitive discordance). CSF mediators significant in univariate analysis went forward to two-way unsupervised hierarchical clustering based on the patterns of relative mediator concentrations.

Results

In univariate analysis 19 of 21 CSF mediators were significantly higher in discordant than non-discordant samples. There were no significant differences between samples with high versus low discordance. The samples grouped into two clusters which corresponded to CSF/plasma discordance (p < 0.0001). In cluster one all mediators had relatively high abundance; this included 18 discordant samples and three non-discordant samples. In cluster two all mediators had relatively low abundance; this included 18 non-discordant samples and one non-discordant sample with ultrasensitive discordance only.

Conclusions

CSF/plasma discordance is associated with potentially damaging neuroinflammatory process. Patients with discordance at lower levels (ie. 0.5–1log₁₀) should also be investigated as mediator profiles were similar to those with discordance >1log₁₀. Sensitive testing may have a role to determine whether ultrasensitive discordance is present in those with low level CSF escape.