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

Changes in Cerebrospinal Fluid, Liver and Intima-media-thickness Biomarkers in Patients with HIV-associated Neurocognitive Disorders Randomized to a Less Neurotoxic Treatment Regimen

The prevalence of neurocognitive impairment in people living with HIV is estimated between 30 and 50%. The pathogenesis of HIV-associated neurocognitive disorders is complex and multifactorial. Aim of the study was to measure the change in CSF biomarkers, Fibroscan and IMT measurements in PLWH with HAND randomized to a less neurotoxic regimen, or continuing their treatment. Adult patients with HAND were screened and enrolled if presenting no major resistance associated mutations, no HIV viral replication, not on efavirenz or darunavir, with R5-tropic HIV and without major confounding conditions. Lumbar puncture, IMT and Fibroscan measurements were performed. After 1:1 randomization to a less neurotoxic regimen consisting of darunavir/cobicistat plus emtricitabine plus maraviroc, or mantaining actual care, tests were repeated after 24 weeks: CSF biomarkes (HIV RNA, tau, p-tau, Beta-amyloid1-42, S100Beta and neopterin) were included. Non-parametric tests (Mann-Whitney and Wilcoxon's) were used. 28 participants completed the study. Male and European ancestry were prevalent; median age was 55 years (51-60). All patients were virally suppressed; median CD4 + count was 626 cell/uL (469-772). Baseline characteristics were similar between the study arms. A significant decrease in CSF p-tau and an increase in CSF neopterin and NFL were observed. We observed a significant reduction in liver stiffness at W24. Despite a small sample size we observed changes in neuromarkers and in hepatic stiffness in patients randomized to the experimental arm. We observed changes in CSF biomarkers (lower phosphorylated-tau and higher neopterin and NFL) that need to be replicated in large cohorts. Subclinical neurotoxicity may be observed in patients with HAND and warrants prospective studies.

Cerebrospinal Fluid CXCL13 as Candidate Biomarker of Intrathecal Immune Activation, IgG Synthesis and Neurocognitive Impairment in People with HIV

Plasma C-X-C-motif chemokine ligand-13 (CXCL13) has been linked to disease progression and mortality in people living with HIV (PLWH) and is a candidate target for immune-based strategies for HIV cure. Its role in central nervous system (CNS) of PLWH has not been detailed. We described CSF CXCL13 levels and its potential associations with neurological outcomes. Cross-sectional study enrolling PLWH without confounding for CXCL13 production. Subjects were divided according to CSF HIV-RNA in undetectable (< 20 cp/mL) and viremics. CSF CXCL13, and biomarkers of blood-brain barrier (BBB) impairment, intrathecal synthesis, and immune activation were measured by commercial immunoturbidimetric and ELISA assays. All subjects underwent neurocognitive assessment. Sensitivity analyses were conducted in subjects with intact BBB only. 175 participants were included. Detectable CSF CXCL13 was more common in the viremic (31.4%) compared to the undetectable group (13.5%; OR 2.9 [1.4-6.3], p = 0.006), but median levels did not change (15.8 [8.2-91.0] vs 10.0 [8.1-14.2] pg/mL). In viremics (n = 86), CXCL13 associated with higher CSF HIV-RNA, proteins, neopterin, intrathecal synthesis and BBB permeability. In undetectable participants (n = 89), CXCL13 associated with higher CD4+T-cells count, CD4/CD8 ratio, CSF proteins, neopterin, and intrathecal synthesis. The presence of CXCL13 in the CSF of undetectable participants was associated with increased odds of HIV-associated neurocognitive disorders (58.3% vs 28.6%, p = 0.041). Sensitivity analyses confirmed all these findings. CXCL13 is detectable in the CSF of PLWH that show increased intrathecal IgG synthesis and immune activation. In PLWH with CSF viral suppression, CXCL13 was also associated with neurocognitive impairment.

Sirtuin-2, NAD-Dependent Deacetylase, Is a New Potential Therapeutic Target for HIV-1 Infection and HIV-Related Neurological Dysfunction

The implementation and access to combined antiretroviral treatment (cART) have dramatically improved the quality of life of people living with HIV (PLWH). However, some comorbidities, such as neurological disorders associated with HIV infection still represent a serious clinical challenge. Soluble factors in plasma that are associated with control of HIV replication and neurological dysfunction could serve as early biomarkers and as new therapeutic targets for this comorbidity. We used a customized antibody array for determination of blood plasma factors in 40 untreated PLWH with different levels of viremia and found sirtuin-2 (SIRT2), an NAD-dependent deacetylase, to be strongly associated with elevated viral loads and HIV provirus levels, as well as with markers of neurological damage (a-synuclein [SNCA], brain-derived neurotrophic factor [BDNF], microtubule-associated protein tau [MAPT], and neurofilament light protein [NFL]). Also, longitudinal analysis in HIV-infected individuals with immediate (n = 9) or delayed initiation (n = 10) of cART revealed that after 1 year on cART, SIRT2 plasma levels differed between both groups and correlated inversely with brain orbitofrontal cortex involution. Furthermore, targeting SIRT2 with specific small-molecule inhibitors in in vitro systems using J-LAT A2 and primary glial cells led to diminished HIV replication and virus reactivation from latency. Our data thus identify SIRT2 as a novel biomarker of uncontrolled HIV infection, with potential impact on neurological dysfunction and offers a new therapeutic target for HIV treatment and cure. IMPORTANCE Neurocognitive disorders are frequently reported in people living with HIV (PLWH) even with the introduction of combined antiretroviral treatment (cART). To identify biomarkers and potential therapeutic tools to target HIV infection in peripheral blood and in the central nervous system (CNS), plasma proteomics were applied in untreated chronic HIV-infected individuals with different levels of virus control. High plasma levels of sirtuin-2 (SIRT2), an NAD+ deacetylase, were detected in uncontrolled HIV infection and were strongly associated with plasma viral load and proviral levels. In parallel, SIRT2 levels in the peripheral blood and CNS were associated with markers of neurological damage and brain involution and were more pronounced in individuals who initiated cART later in infection. In vitro infection experiments using specific SIRT2 inhibitors suggest that specific targeting of SIRT2 could offer new therapeutic treatment options for HIV infections and their associated neurological dysfunction.

CD8 Encephalitis in HIV: A Review of This Emerging Entity

INTRODUCTION

Encephalitis is a life-threatening neurological condition with multiple causes in the setting of Human Immunodeficiency Virus (HIV). CD8 Encephalitis (CD8E) is a newly recognised condition which can present in an acute manner, with pertinent features including classical radiological findings with an intense brain parenchymal infiltration of CD8+ T cells. This review attempted to clarify the symptomatology, distribution and determinants of this condition, as well as to examine its vast unknowns.

METHODS

A literature review was undertaken in July 2022, utilising the PubMed and Google Scholar databases. Papers published between 2006-2022 were reviewed. Eighteen papers, totalling 57 patients, were found and analysed. Statistical analysis was undertaken using Chi-squared and Wilcoxon rank-sum tests as appropriate, with p < 0.05 deemed significant.

RESULTS

In this review, 57 patients were identified, with a female (61%, 34/56) and Black African (70%, 40/57) preponderance. Females were more likely to present with headache (p = 0.006), and headache was more likely to be present in those who died (p = 0.02). There was no statistically significant association between baseline CD4 count (p = 0.079) and viral load (p = 0.72) with disease outcome. Overall, 77% (41/53) of patients had classical imaging findings, including bilateral gadolinium-enhancing punctate and perivascular white matter lesions. However, many patients (23/57) required a brain biopsy as part of their diagnostic workup. Corticosteroid treatment was commonly prescribed in patients (64%, 35/55) and had a mortality benefit, with an overall survival in this group of 71% (p = 0.0008). In those who died, median survival was 5.5 months. In rare instances, recurrence of the disease was noted, which responded poorly to treatment.

DISCUSSION

CD8E represents a new and complex condition with few risk factors identified for its occurrence. The presenting symptoms are broad, but headache appears to be more common in females and more significantly associated with death. Though rare, CD8E is likely under-diagnosed, possibly due to overlapping features with other illnesses and lack of physician experience in its recognition and management. Corticosteroids demonstrate a clear mortality benefit, but more studies are required to determine their optimal dosing and duration, as well as the use of steroid-sparing agents. Further reviews should help to better determine the risk factors for the condition, as well as non-invasive biomarkers, to aid in diagnosis and help to predict poor prognosis and disease recurrence.

Differentiating neurosarcoidosis from multiple sclerosis using combined analysis of basic CSF parameters and MRZ reaction

Background

Neurosarcodosis is one of the most frequent differential diagnoses of multiple sclerosis (MS) and requires central nervous system (CNS) biopsy to establish definite diagnosis according to the latest consensus diagnostic criteria. We here analyzed diagnostic values of basic cerebrospinal fluid (CSF) parameters to distinguish neurosarcoidosis from MS without CNS biopsy.

Methods

We retrospectively assessed clinical, radiological and laboratory data of 27 patients with neurosarcoidosis treated at our center and compared following CSF parameters with those of 138 patients with relapsing-remitting MS: CSF white cell count (WCC), CSF/serum albumin quotient (Q_alb), intrathecal production of immunoglobulins including oligoclonal bands (OCB), MRZ reaction, defined as a polyspecific intrathecal production of IgG reactive against ≥2 of 3 the viruses measles (M), rubella (R), and zoster (Z) virus, and CSF lactate levels. Additional inflammatory biomarkers in serum and/or CSF such as neopterin, soluble interleukin-2 receptor (sIL-2R) and C-reactive protein (CRP) were assessed.

Results

There was no significant difference in the frequency of CSF pleocytosis, but a CSF WCC > 30/μl was more frequent in patients with neurosarcoidosis. Compared to MS, patients with neurosarcoidosis showed more frequently an increased Q_alb and CSF lactate levels as well as increased serum and CSF levels of sIL-2R, but a lower frequency of intrathecal IgG synthesis and positive MRZ reaction. Positive likelihood ratio (PLR) of single CSF parameters indicating neurosarcoidosis was highest, if (a) CSF WCC was >30/μl (PLR 7.2), (b) Q_alb was >10 × 10^-3 (PLR 66.4), (c) CSF-specific OCB were absent (PLR 11.5), (d) CSF lactate was elevated (PLR 23.0) or (e) sIL-2R was elevated (PLR>8.0). The combination of (a) one of three following basic CSF parameters, i.e., (a.1.) CSF WCC >30/ul, or (a.2.) Q_Alb >10 × 10^-3, or (a.3.) absence of CSF-specific OCB, and (b) absence of positive MRZ reaction showed the best diagnostic accuracy (sensitivity and specificity each >92%; PLR 12.8 and NLR 0.08).

Conclusion

Combined evaluation of basic CSF parameters and MRZ reaction is powerful in differentiating neurosarcoidosis from MS, with moderate to severe pleocytosis and Q_Alb elevation and absence of intrathecal IgG synthesis as useful rule-in parameters and positive MRZ reaction as a rule-out parameter for neurosarcoidosis.

Correlations between cerebrospinal fluid biomarkers, neurocognitive tests, and resting-state electroencephalography (rsEEG) in patients with HIV-associated neurocognitive disorders

HIV-associated neurocognitive disorders (HAND) are highly prevalent in people living with HIV (PLWH) despite successful treatment with combination antiretroviral therapy (cART). HAND pathogenesis is complex and definitive surrogate biomarkers are not clearly defined. Brain function has been assessed through the evaluation of cortical source rhythms with delta waves associated with neurological impairment. The aim of this study was to assess the correlation between EEG cortical sources, cerebrospinal fluid (CSF) biomarkers, and neurocognitive tests in PLWH with HAND. PLWH with HAND without significant comorbidities were enrolled. Baseline rsEEG-LORETA waves, CSF biomarkers (t-tau, p-tau, β-amiloid₄₂, neopterin, S100β), and neurocognitive tests were correlated and compared through non-parametric tests (Spearman's rho and Mann-Whitney); data are presented as medians (interquartile ranges). Fifty-four patients were enrolled. Median time of suppressed HIV-RNA and CD4⁺ T-lymphocyte were 10 years (5.5-15) and 691/uL (477-929). Thirty-nine participants (72%) underwent CSF collection: abnormal biomarkers were found in a small percentage. Only neopterin showed a statistically significant correlation with delta activity [parietal (rho 0.579; p < 0.001), occipital (rho 0.493; p = 0.007), and global sources (rho 0.464 p = 0.011)]. Seven patients (12.9%) showed an abnormal neopterin level (> 1.5 ng/mL) with significantly higher delta source activity compared to the ones with in-range concentrations. We observed a statistically significant correlation between working memory test Trail Making B with both CSF neopterin levels and delta waves (p values < 0.05). In a small sample of PLWH with HAND, we observed that higher CSF neopterin levels were associated with higher EEG delta waves and worse working memory tests.

Presence of Epstein-Barr virus DNA in cerebrospinal fluid is associated with greater HIV RNA and inflammation

OBJECTIVE

The current study aimed to investigate whether cerebrospinal fluid (CSF) Epstein-Barr virus (EBV) or cytomegalovirus (CMV) DNA was associated with viral, inflammatory and neuronal damage biomarkers in people living with HIV (PLWH).

DESIGN

A cross-sectional diagnostic study on CSF fluid samples in patients undergoing lumbar punctures for clinical reasons, to better understand the role of EBV and CMV in the CNS on HIV RNA replication, blood-brain-barrier (BBB) damage and biomarkers of neuronal damage/inflammation.

METHODS

EBV, CMV DNA and HIV RNA were measured on CSF, through real time (RT)-PCR, from PLWHs undergoing lumbar punctures for clinical reasons (excluding oncho-haematological comorbidities). Immune-enzymatic assays evaluated blood-brain barrier inflammation and damage. Patients were stratified according to plasma HIV RNA levels in viremic (≥50 copies/ml) and aviremic (<50 copies/ml).

RESULTS

We included 297 participants. Among 167 viremic patients CSF EBV and CMV DNA were detectable in 42 (25.1%) and 10 (6.3%) participants; among 130 aviremic individuals CSF EBV and CMV DNA were detectable in 12 (9.2%) and 0 (0%) participants, respectively. In viremic group detectable CSF EBV DNA was associated with CSF pleocytosis (P < 0.001), higher CSF HIV RNA (P < 0.001) and neopterin levels (P = 0.002). In aviremic participants detectable EBV DNA was associated with pleocytosis (P = 0.056), higher neopterin (P = 0.027) and immune globulins (P = 0.016) in the CSF; CSF escape was more common in those with detectable EBV DNA (50 vs. 21.2%, P = 0.036).

CONCLUSION

EBV DNA was frequently detected in the CSF of viremic and fewer aviremic patients on antiretroviral treatment. In PLWH without clinical evidence of encephalitis CSF EBV DNA was associated with higher biomarkers levels of neuronal damage/inflammation. The role of EBV reactivation in HIV-associated central nervous system disorders warrants further studies.

Markers of CNS Injury in Adults Living With HIV With CSF HIV Not Detected vs Detected <20 Copies/mL

The presence of quantifiable HIV RNA in cerebrospinal fluid (CSF) during antiretroviral therapy (ART) can associate with central nervous system (CNS) pathology, but the significance of RNA detected below the limit of quantification (LOQ) on a standard assay during ART remains unknown. We compared CNS parameters between individuals with CSF RNA detected below the LOQ (20 copies/mL) with those with HIV RNA not detected. Detection of CSF HIV RNA associated with decreased blood-brain barrier integrity and with decreased executive function, but not with CNS immune activation or poorer performance in overall neuropsychological testing.

Neuronal damage and neuroinflammation markers in patients with autoimmune encephalitis and multiple sclerosis

Inflammatory diseases of the central nervous system (CNS) are a diagnostic challenge to clinicians. Autoimmune encephalitis (AE) is an important diagnostic consideration in patients with CNS inflammatory disorders; despite of a wide range of neuropsychiatric symptoms it should be diagnosed as soon as possible and the patient transferred to the neurologist. We studied a group of AE patients (n = 24) as compared to multiple sclerosis (MS, n = 61) and control (n = 19) groups. Detailed clinical pictures of patients are presented. We focused on relevant cerebrospinal fluid (CSF) tests like protein levels, cytosis and oligoclonal bands, neuroinflammation indices (interleukin-6, soluble receptor of IL-6, neopterin, anti-ribosomal proteins antibodies) and markers of neurodegeneration (phosphorylated neurofilament heavy chain, pNfh). Elevated neopterin level was found in AE group as compared to the MS and control groups, while protein and pNfh were increased in both AE and MS groups. In the MS group, the cytosis and soluble receptor of IL-6 were higher as compared to the control group. Anti-ribosomal proteins antibodies were increased in a single patient with AE. High levels of protein were predictive of mortality in AE patients, while IL-6 and pNfh were elevated in severe AE patients. AE patients with paraneoplastic etiology demonstrated oligoclonal bands positivity. Taken together, our results suggest the neopterin as an additional marker of autoimmune brain inflammation. Though higher levels of protein, IL-6 and pNfh were found in patients with severe disease progression and death, prognostic values of these markers should be validated in larger cohorts of patients.

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.

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

OBJECTIVE

HIV infection chronically affects the central nervous system (CNS). Olfactory mucosa is a unique site in the respiratory tract that is directly connected to the CNS; thus we wanted to evaluate olfactory mucosa as a surrogate of CNS sampling.

DESIGN

We conducted a preliminary study examining HIV populations and susceptible cells in the olfactory mucosa.

METHODS

Olfactory mucosa was sampled by minimally invasive brushing. Cerebrospinal fluid (CSF) analyses were performed as per routine clinical procedures. Olfactory marker protein, CD4+, CD8+, and trans-activator of transcription (TAT) expressions were assessed by immunohistochemistry. Plasma, CSF, and olfactory mucosa HIV-RNA were quantified using the Cobas AmpliPrep/Cobas TaqMan assay, whereas HIV proviral DNA was evaluated on peripheral blood mononuclear cell and olfactory mucosa. HIV-1 env deep sequencing was performed for phylogenetic analysis.

RESULTS

Among ART-naive participants, 88.2% (15/17), and among ART-treated participants, 21.4% (6/28) had detectable HIV-RNA in samples from their olfactory mucosa; CSF escape was more common in patients with olfactory mucosa escape (50 vs. 7.9%; P = 0.010). Olfactory mucosa samples contained few cells positive for CD4, CD8, or HIV-DNA, and no HIV TAT-positive cells, indicating that this approach efficiently samples virions in the olfactory mucosa, but not HIV-infected cells. Yet, using a deep sequencing approach to phylogenetically compare partial HIV env genes in five untreated participants, we identified distinct viral lineages in the OM.

CONCLUSIONS

The results of this study suggest that nasal brushing is a well tolerated and useful technique for sampling the olfactory mucosa. HIV-RNA was detected in most naïve and in some treated patients, warranting larger longitudinal studies.

Peripheral and cerebrospinal fluid immune activation and inflammation in chronically HIV-infected patients before and after virally suppressive combination antiretroviral therapy (cART)

Cerebrospinal fluid (CSF)/plasma HIV-RNA ratio has been associated with residual neurocognitive impairment on cART, leading us to hypothesize a specific peripheral and/or CSF immune feature in patients with high CSF/plasma ratio (≥ 1). In patients with diverse pre-cART CSF/plasma ratio (61/70 with CSF/plasma ratio < 1, L-CSF, 9/70 with CSF/plasma ratio ≥ 1, H-CSF), we investigated the effects of 12 months of effective cART on peripheral and CSF inflammatory markers, on T cell activation/maturation and HIV/CMV-specific intracellular cytokine pattern. We also studied the possible clinical association between peripheral/CSF pro-inflammatory milieu and neurocognitive screening tests (MMSE, FAB, IHDS). Prior to cART, the two groups were comparable for peripheral and CSF inflammation, T cell activation/proliferation and maturation, and HIV/CMV-specific response. Upon cART initiation, both H-CSF and L-CSF featured a significant reduction in plasma TNF-α and circulating CD8 activation, with a redistribution of memory/naïve T cell subsets in L-CSF alone. In the CSF compartment, cART seemed able to reduce pro-inflammatory cytokine/chemokine levels in both H-CSF and L-CSF patients. Interestingly, despite a reduction in the pro-inflammatory milieu, no changes were shown in neurocognitive screening tests in both patients' groups. We hereby show that 12-month cART is able to reduce intratechal and peripheral pro-inflammatory burden; a longer cART exposure and a more comprehensive neuropsychological evaluation might be necessary to gain a broader insight into the possible effects on neurocognitive performance.