Cerebrospinal fluid HIV-1 RNA levels in asymptomatic patients with early stage chronic HIV-1 infection: support for the hypothesis of local virus replication

HIV-1 is Transported into the Central Nervous System by Trafficking Infected Cells

Background

In this work, we carried out a cross-sectional study examining HIV-1 and HCV free virus concentrations in blood and cerebrospinal fluid (CSF) to determine whether HIV-1 enters the central nervous system (CNS) passively as virus particles or in the context of migrating infected cells. If virions migrate freely across the blood-cerebrospinal fluid barrier (BCSFB) or the blood-brain barrier (BBB) then HCV and HIV-1 would be detectable in the CSF at proportions similar to that in the blood. Alternatively, virus entry as an infected cell would favor selective entry of HIV-1.

Methods

We measured HIV-1 and HCV viral loads in the CSF and blood plasma of 4 co-infected participants who were not on antiviral regimens for either infection. We also generated HIV-1 env sequences and performed phylogenetic analyses to determine whether HIV-1 populations in the CSF of these participants were being maintained by local replication.

Results

While CSF samples taken from all participants had detectable levels of HIV-1, HCV was not detectable in any of the CSF samples despite participants having HCV concentrations in their blood plasma, which exceeded that of HIV-1. Further, there was no evidence of compartmentalized HIV-1 replication in the CNS (Supplementary Figure 1). These results are consistent with a model where HIV-1 particles cross the BBB or the BCSFB within infected cells. In this scenario, we would expect HIV-1 to reach the CSF more readily because the blood contains a much greater number of HIV-infected cells than HCV-infected cells.

Conclusions

HCV entry into the CSF is restricted, indicating that virions do not freely migrate across these barriers and supporting the concept that HIV-1 is transported across the BCSFB and/or BBB by the migration of HIV-infected cells as part of an inflammatory response or normal surveillance.

Viruses and Endogenous Retroviruses as Roots for Neuroinflammation and Neurodegenerative Diseases

Many neurodegenerative diseases are associated with chronic inflammation in the brain and periphery giving rise to a continuous imbalance of immune processes. Next to inflammation markers, activation of transposable elements, including long intrespersed nuclear elements (LINE) elements and endogenous retroviruses (ERVs), has been identified during neurodegenerative disease progression and even correlated with the clinical severity of the disease. ERVs are remnants of viral infections in the human genome acquired during evolution. Upon activation, they produce transcripts and the phylogenetically youngest ones are still able to produce viral-like particles. In addition, ERVs can bind transcription factors and modulate immune response. Being between own and foreign, ERVs are reviewed in the context of viral infections of the central nervous system, in aging and neurodegenerative diseases. Moreover, this review tests the hypothesis that viral infection may be a trigger at the onset of neuroinflammation and that ERVs sustain the inflammatory imbalance by summarizing existing data of neurodegenerative diseases associated with viruses and/or ERVs.

Monocytes and macrophages in COVID-19: Friends and foes

The COVID-19 is a novel infectious disease caused by SARS-CoV-2 and is known as a pandemic emergency that has led to a high rate of mortality throughout the world. Evidence has indicated that hyperinflammatory responses triggered by SARS-CoV-2 are the main cause of pathogenicity in the severe cases of patients who have died during the current viral disease. Monocytes and macrophages as the most important cells of the innate arm of the immune system play a substantial part in the body's defense against viral infections. They mainly respond to the microbial antigens by producing inflammatory mediators to remove pathogens and repair tissue injury. Nevertheless, aberrant alterations in their function such as cytokine storm can be so harmful to the host in the acute respiratory distress syndrome cases caused by SARS-CoV-2. Moreover, inflammatory responses stimulated by SARS-CoV-2 have affected the other vital organs of the body including the heart. As cardiovascular complications in COVID-19 patients have been reported in several studies. During the infection, monocytes and macrophages may be involved in the hypersensitive and exacerbated reactions that contribute to the tissue damage, especially lung injury resulted in its dysfunction and respiratory disorder. In this review, we discuss both advantageous and disadvantageous about the pathological potential of monocytes and macrophages during the infection of SARS-CoV-2 to clarify their mutual effects on immune processing as a fist line defender in the current disease.

Ocular syphilis: case series (2000-2015) from 2 tertiary care centres in Montreal, Canada

OBJECTIVE

To describe the demographics, clinical presentation, proportion of co-infection with human immunodeficiency virus (HIV), and treatment of patients with ocular syphilis seen at the ophthalmology department of 2 tertiary centres in Montreal, Canada.

DESIGN

Retrospective case series.

PARTICIPANTS AND METHODS

A total of 169 eyes of 115 patients, seen between 2000 and 2015, with a positive syphilis treponemal serology and a likely syphilis-related ophthalmologic diagnosis. Subgroup analysis was performed between HIV-infected and HIV-uninfected patients.

RESULTS

Mean age of onset was 55 years, and 79% were male. Mean presenting logMAR visual acuity was 0.7. HIV status was available for 66%, of whom 49% were HIV-infected. The anatomical ocular diagnoses included isolated anterior uveitis (18%) and posterior segment involvement (42%). Both eyes were affected in 47%. Lumbar puncture (LP) was performed in 55%, of whom 22% had a positive cerebrospinal fluid (CSF) Venereal Disease Research Laboratory (VDRL) test. Antibiotherapy, consisting of intravenous penicillin alone or in addition to intramuscular benzathine penicillin, was administered in 65 patients (69%). Treatment allowed a visual improvement of -0.23 logMAR. HIV-infected patients were younger men (p < 0.01) and had more abnormal CSF analysis (p = 0.02), but there were no statistically significant differences in the anatomical location of ocular inflammation or visual function improvement.

CONCLUSIONS

Given its varied presentations, syphilis must always be part of the differential diagnosis of intraocular inflammation. HIV testing and an LP are required in the evaluation of ocular syphilis, which should be treated as neurosyphilis with the appropriate regimen.

Real-time polymerase chain reaction for diagnosis and management of HIV-induced uveitis

Intraocular (IO) inflammation in patients with Human immune deficiency virus (HIV) infection can be due to opportunistic infections, immune recovery uveitis, drugs used in the management or a primary manifestation of HIV itself. We studied the role of RT-PCR for HIV RNA in confirming the diagnosis of HIV induced uveitis and its useful in the management and follow-up of these patients.

Human Immunodeficiency Virus in the Brain-Culprit or Facilitator?

Introduction:

Human immunodeficiency virus (HIV) enters the brain early, where it can persist, evolve, and become compartmentalized. Central nervous system (CNS) disease can be attributed to HIV alone or to the complex interplay between the virus and other neurotropic pathogens.

Aim:

The current review aims to describe the direct impact of HIV on the brain as well as its relationship with other pathogens from a practitioner’s perspective, to provide a general clinical overview, brief workup, and, whenever possible, treatment guidance.

Methods:

A review of PubMed was conducted to identify studies on neuropathogenesis of HIV in relation to host responses. Furthermore, the interaction between the CNS pathogens and the host damage responses were revised in the setting of advanced and also well-controlled HIV infection.

Results:

Similar to other pathogens, HIV leads to CNS immune activation, inflammation, and viral persistence. Therefore, almost half of the infected individuals present with neurocognitive disorders, albeit mild. Compartmentalized HIV in the CNS can be responsible in a minority of cases for the dramatic presentation of symptomatic HIV escape. Disruption of the immune system secondary to HIV may reactivate latent infections or allow new pathogens to enter the CNS. Opportunistic infections with an inflammatory component are associated with elevated HIV loads in the cerebrospinal fluid and also with greater cognitive impairment. The inflammatory immune reconstitution syndrome associated with CNS opportunistic infections can be a life-threatening condition, which needs to be recognized and managed by efficiently controlling the pathogen burden and timely balanced combination antiretroviral therapy. Latent neurotropic pathogens can reactivate in the brain and mimic HIV-associated severe neurological diseases or contribute to neurocognitive impairment in the setting of stable HIV infection.

Conclusions:

As HIV can be responsible for considerable brain damage directly or by facilitating other pathogens, more effort is needed to recognize and manage HIV-associated CNS disorders and to eventually target HIV eradication from the brain.

Antiretroviral-treated HIV-1 patients can harbour resistant viruses in CSF despite an undetectable viral load in plasma

Background

HIV therapy reduces the CSF HIV RNA viral load (VL) and prevents disorders related to HIV encephalitis. However, these brain disorders may persist in some cases. A large population of antiretroviral-treated patients who had a VL > 1.7 log 10 copies/mL in CSF with detectable or undetectable VL in plasma associated with cognitive impairment was studied, in order to characterize discriminatory factors of these two patient populations.

Methods

Blood and CSF samples were collected at the time of neurological disorders for 227 patients in 22 centres in France and 1 centre in Switzerland. Genotypic HIV resistance tests were performed on CSF. The genotypic susceptibility score was calculated according to the last Agence Nationale de Recherche sur le Sida et les hépatites virales Action Coordonnée 11 (ANRS AC11) genotype interpretation algorithm.

Results

Among the 227 studied patients with VL > 1.7 log 10 copies/mL in CSF, 195 had VL detectable in plasma [median (IQR) HIV RNA was 3.7 (2.7-4.7) log 10 copies/mL] and 32 had discordant VL in plasma (VL < 1.7 log 10 copies/mL). The CSF VL was lower (median 2.8 versus 4.0 log 10 copies/mL; P  <   0.001) and the CD4 cell count was higher (median 476 versus 214 cells/mm 3 ; P  <   0.001) in the group of patients with VL < 1.7 log 10 copies/mL in plasma compared with patients with plasma VL > 1.7 log 10 copies/mL. Resistance to antiretrovirals was observed in CSF for the two groups of patients.

Conclusions

Fourteen percent of this population of patients with cognitive impairment and detectable VL in CSF had well controlled VL in plasma. Thus, it is important to explore CSF HIV (VL and genotype) even if the HIV VL is controlled in plasma because HIV resistance may be observed.

Prevalence and Correlates of Persistent HIV-1 RNA in Cerebrospinal Fluid During Antiretroviral Therapy

BACKGROUND

 Neurocognitive disorders remain common among human immunodeficiency virus (HIV)-positive adults, perhaps owing to persistent HIV-1 RNA in cerebrospinal fluid (CSF) during antiretroviral therapy (ART).

METHODS

 Using a single-copy assay, we measured HIV-1 RNA levels in CSF and plasma specimens from 220 HIV-positive adults who were taking suppressive ART. Fifty-five participants were tested twice.

RESULTS

 HIV-1 RNA was detected in 42.3% of CSF and 65.2% of plasma samples. Correlates of higher CSF HIV-1 RNA levels included higher nadir and current CD4⁺ T-cell counts, a plasma HIV-1 RNA level of ≥ 1 copy/mL, and a lower central nervous system penetration-effectiveness score (model P < .001). Worse neurocognitive performance was associated with discordance in HIV-1 RNA detection between plasma and CSF, lower overall CSF HIV-1 RNA level, and longer ART duration, among others (model P < .001). In the longitudinal subgroup, CSF HIV-1 RNA persisted in most participants (69%) over 7 months.

CONCLUSIONS

 Low-level HIV-1 RNA in CSF is common during suppressive ART and is associated with low-level HIV-1 RNA in blood, better immune status, and lower ART drug distribution into CSF. The association between HIV-1 RNA discordance and HIV-associated neurocognitive disorder (HAND) may reflect compartmentalization. The relationship between HAND, lower HIV-1 RNA levels in CSF, and lower CD4⁺ T-cell counts may reflect disturbances in the immune response to HIV-1 in the CNS.

Ocular and Cerebrospinal Fluid Penetration of Antiretroviral Agents

PURPOSE

The ocular penetration of systemically administered antiretroviral drugs (ARVs), which is important in the clinical setting of HIV uveitis, is unknown. This study aimed to assess the ocular penetration of different antiretroviral drugs in an animal model.

METHODS

Twenty-five male New Zealand white rabbits were assigned to one of five treatment groups. Each group received a single oral dose of an antiretroviral drug (lamivudine, tenofovir, efavirenz, lopinavir, and raltegravir). These 5 drugs represent 4 different ARV drug classes [nucleoside reverse transcriptase inhibitors (NRTI), non-NRTI, protease inhibitors, and integrase inhibitors]. Serum, cerebrospinal fluid (CSF), and aqueous and vitreous humor samples were collected at the time of theoretical maximum serum concentration of each respective drug, for example, lamivudine 1 h, tenofovir 1 h, efavirenz 5 h, lopinavir 4 h, and raltegravir 3 h. The drug concentration in each sample was determined by means of high-performance liquid chromatography and mass spectrometry.

RESULTS

After a single oral dose, measurable levels of all five ARVs administered could be detected in all 4 body compartments. The limit of detection based on a signal-to-noise ratio of 1:3 for the antiretroviral agents was as follows: 1 part per billion (ppb) for lamivudine, tenofovir, and efavirenz and 0.1 ppb for lopinavir and raltegravir. The IC50 (inhibitory concentration where 50% of viral replication is inhibited by a drug) was reached for all drugs in the serum and CSF. In the aqueous humor, lopinavir failed to reach IC50 and in the vitreous humor, only efavirenz and lopinavir attained IC50 levels.

CONCLUSION

After a single oral dose, measurable levels of all 4 classes of ARVs could be detected in all 4 body compartments sampled. In the eye, IC50 levels were lower in the vitreous humor than in aqueous humor. IC50 levels in the serum were higher than in the CSF.

Neuropathological sequelae of Human Immunodeficiency Virus and apathy: A review of neuropsychological and neuroimaging studies

Apathy remains a common neuropsychiatric disturbance in the Human Immunodeficiency Virus (HIV-1) despite advances in anti-retroviral treatment (ART). The goal of the current review is to recapitulate findings relating apathy to the deleterious biobehavioral effects of HIV-1 in the post-ART era. Available literatures demonstrate that the emergence of apathy with other neurocognitive and neuropsychiatric symptoms may be attributed to neurotoxic effects of viral proliferation, e.g., aggregative effect of Tat and gp120 on apoptosis, transport and other enzymatic reactions amongst dopaminergic neurons and neuroglia. An assortment of neuroimaging modalities converge on the severity of apathy symptoms associated with the propensity of the virus to replicate within frontal-striatal brain circuits that facilitate emotional processing. Burgeoning research into functional brain connectivity also supports the effects of microvascular and neuro-inflammatory injury linked to aging with HIV-1 on the presentation of neuropsychiatric symptoms. Summarizing these findings, we review domains of HIV-associated neurocognitive and neuropsychiatric impairment linked to apathy in HIV. Taken together, these lines of research suggest that loss of affective, cognitive and behavioral inertia is commensurate with the neuropathology of HIV-1.

Comparison of models for analyzing two-group, cross-sectional data with a Gaussian outcome subject to a detection limit

A potential difficulty in the analysis of biomarker data occurs when data are subject to a detection limit. This detection limit is often defined as the point at which the true values cannot be measured reliably. Multiple, regression-type models designed to analyze such data exist. Studies have compared the bias among such models, but few have compared their statistical power. This simulation study provides a comparison of approaches for analyzing two-group, cross-sectional data with a Gaussian-distributed outcome by exploring statistical power and effect size confidence interval coverage of four models able to be implemented in standard software. We found using a Tobit model fit by maximum likelihood provides the best power and coverage. An example using human immunodeficiency virus type 1 ribonucleic acid data is used to illustrate the inferential differences in these models.

Cellular Composition of Cerebrospinal Fluid in HIV-1 Infected and Uninfected Subjects

In order to characterize the cellular composition of cerebrospinal fluid (CSF) in a healthy state and in the setting of chronic pleocytosis associated with HIV-1 (HIV) infection, multi-parameter flow cytometry was used to identify and quantitate cellular phenotypes in CSF derived from HIV-uninfected healthy controls and HIV-infected subjects across a spectrum of disease and treatment. CD4+ T cells were the most frequent CSF population and the CD4:CD8 ratio was significantly increased in the CSF compared to blood (p = 0.0232), suggesting preferential trafficking of CD4+ over CD8+ T cells to this compartment. In contrast, in HIV-infection, CD8+ T cells were the major cellular component of the CSF and were markedly increased compared to HIV-uninfected subjects (p<0.001). As with peripheral blood, the CSF CD4:CD8 ratio was reversed in HIV-infected subjects compared to HIV-uninfected subjects. Monocytes, B cells and NK cells were rare in the CSF in both groups, although absolute counts of CSF NK cells and B cells were significantly increased in HIV-infected subjects (p<0.05). Our studies show that T cells are the major cellular component of the CSF in HIV-infected and uninfected subjects. The CSF pleocytosis characteristic of HIV infection involves all lymphocyte subsets we measured, except for CD4+ T cells, but is comprised primarily of CD8+ T cells. The reduced proportion of CD4+ T cells in the CSF may reflect both HIV-related peripheral loss and changes in trafficking patterns in response to HIV infection in the central nervous system.

Clinical manifestations of human immunodeficiency virus-induced uveitis

PURPOSE

To describe the clinical manifestations of patients with human immunodeficiency virus (HIV)-induced uveitis in Thailand.

DESIGN

Prospective cohort study of 6 patients with HIV-induced uveitis.

PARTICIPANTS

Six patients (8 eyes) with HIV-induced uveitis who had an extremely high intraocular: plasma HIV-1 RNA ratio.

METHODS

The clinical manifestations and laboratory findings are reported of 6 consecutive patients with HIV-induced uveitis who had an extremely high intraocular-to-plasma HIV-1 RNA ratio and were diagnosed between July 2009 and May 2011.

MAIN OUTCOME MEASURES

Clinical manifestations and laboratory findings.

RESULTS

Human immunodeficiency virus-induced uveitis was diagnosed in 4 men and 2 women with an average age of 41 years at presentation. None of the patients were receiving highly active anti-retroviral therapy (HAART) or had clinical or laboratory evidence, or both, of opportunistic infections. The mean plasma load was 218 688 copies/ml (median, 137 500 copies/ml; range, 24 900-540 000 copies/ml), and the mean intraocular HIV load was 20 937 755 copies/ml (median, 7 499 000 copies/ml; range, 2 460 000-89 800 000 copies/ml). The average CD4 cell count was 192 cells/μl (median, 248 cells/μl; range, 5-342 cells/μl). All the patients had decreased vision, and none had conjunctival hyperemia. The anatomic location of uveitis was anterior in all patients, and associated vitreitis was present in 4 patients; none exhibited retinal lesions or scars. Anterior segment inflammation and keratic precipitates were observed in all patients, and none responded to topical corticosteroid therapy. After the administration of HAART, the intraocular inflammation disappeared entirely within several weeks in all of the patients and the intraocular and plasma HIV loads decreased.

CONCLUSIONS

Human immunodeficiency virus-induced uveitis should be suspected in HAART-naïve, HIV-positive patients or in those in whom this treatment fails and who have anterior uveitis without any retinal lesions and exhibit no response to topical corticosteroids. The concurrent determination of HIV load in the intraocular fluids and plasma may clarify the cause of HIV-associated uveitis.

Kinetics of HIV-1 in cerebrospinal fluid and plasma in cryptococcal meningitis

In order to determine HIV-1 kinetics in cerebrospinal fluid (CSF) and plasma in patients with cryptococcal meningitis (CM), we undertook a prospective collection of paired CSF/plasma samples from antiretroviral therapy-free HIV-infected patients with CM. Samples were obtained at baseline (S1) and at the second (S2) and third (S3) weeks of antifungal therapy. HIV-1 CSF concentrations were significantly lower in both S2 and S3 with respect to S1. Plasma concentrations remained stable. HIV-1 concentrations were higher in plasma than CSF in all cases. Patients who survived the episode of CM (but not those who died) showed a decrease in CSF viral load, what suggests different viral kinetics of HIV-1 in the CSF according to the clinical course of this opportunistic disease.

Factors associated with cerebrospinal fluid HIV RNA in HIV infected subjects undergoing lumbar puncture examination in a clinical setting

BACKGROUND

Cerebrospinal fluid (CSF) HIV RNA load may be associated with central nervous system (CNS) disease in HIV infected subjects. We investigated parameters associated with CSF HIV RNA within a large clinical cohort.

METHODS

All HIV infected subjects undergoing CSF examination including assessment of CSF HIV RNA at St. Mary's Hospital, London, UK between January 2008 and October 2010 were included. Parameters associated with a detectable CSF HIV RNA load were assessed using linear regression modelling. CSF viral escape was defined as CSF RNA >0.5 log(10) copies/mL greater than plasma HIV RNA and >200 copies/mL where plasma HIV RNA <50 copies/mL.

RESULTS

Of 142 subjects, 99 were receiving antiretroviral therapy (ART). Plasma HIV RNA was <50 copies/mL in 69 subjects. CSF examination was performed for investigation of presumed HIV encephalopathy (IxHE, n = 57), other CNS diseases considered HIV related (n = 39), syphilis (n = 20) and CNS presentations not considered HIV related (n = 26). CSF viral escape was present in 30/142 (21%) subjects overall and in 9/69 (13%) of those on ART with undetectable plasma HIV RNA. Overall, plasma HIV RNA load was significantly associated with detectable CSF HIV RNA (p ≤ 0.001). In subjects with plasma HIV RNA <50 copies/mL, only CNS penetration effectiveness (CPE, 2008) score of <2 was significantly associated with detectable CSF HIV RNA (p = 0.044). In patients undergoing LP for IxHE both plasma HIV RNA and CPE scores were independently associated with detectable CSF HIV RNA (p = 0.019 & 0.003 respectively) which was not observed in subjects undergoing CSF examination for other medical reasons.

CONCLUSIONS

In a clinical setting, CSF viral escape is observed frequently in 21% of subjects and is associated with different parameters depending on the clinical scenario.

Analysis of correlation between cerebrospinal fluid and plasma HIV-1 RNA levels in patients with neurological opportunistic diseases

The question of whether HIV-1 RNA in cerebrospinal fluid (CSF) is derived from viral replication in the central nervous system or simply reflects the transit of infected lymphocytes from the blood compartment has long been a matter of debate. Some studies found no correlation between CSF and plasma viral load, whereas others did. The lack of a correlation between the two compartments suggests that the presence of HIV-1 RNA is not simply due to the passive passage of the virus from blood to CSF but rather due to intrathecal replication. To evaluate the correlation between plasma and CSF HIV-1 RNA levels and to identify situations in which there is no correlation between the two compartments, seventy patients were prospectively studied. The association between CSF and plasma viral load was evaluated in the total population and in subgroups of patients with similar characteristics. A correlation between the CSF and plasma compartments was observed for patients undergoing highly active antiretroviral therapy (HAART), those with a CD4 T lymphocyte count lower than 200 cells/mm³, and those with increased CSF protein content. On the other hand, no correlation was observed for patients without adequate virological control, who had a CD4 count higher than 200 cells/mm³ and who did not use HAART. The correlation between the two compartments observed in some patients suggests that CSF HIV-1 RNA levels may reflect plasma levels in these subjects. In contrast, the lack of a correlation between the two compartments in patients who were not on HAART and who had normal CSF proteins and a poor virological control possibly indicates compartmentalization of the virus in CSF and, consequently, plasma-independent intrathecal viral replication.

HIV coreceptor tropism in paired plasma, peripheral blood mononuclear cell, and cerebrospinal fluid isolates from antiretroviral-naïve subjects

A survey of HIV coreceptor usage in cerebrospinal fluid (CSF) samples, peripheral blood mononuclear cells (PBMCs), and plasma samples from naïve seropositive patients was conducted. One hundred patients were enrolled in this study. Of the 100 patients, 36 had a primary or recent infection (P-RI), 31 had an early chronic infection (>350 CD4 cells) (ECI), and 33 had a late chronic infection (LCI). All 3 compartments were sampled in a subset of 33 participants, while the remaining 67 patients provided plasma samples and PBMCs only. Seventy-seven patients harbored the R5 virus in plasma samples and had a significantly higher median and percentage of CD4(+) T cells than patients with X4 virus (437 and 281 cells/μl, respectively; P = 0.0086; 20.6% and 18.6%, respectively). The X4 strain was detected more frequently in patients with LCI than in patients with P-RI or ECI (39.3%, 19.4%, and 9.6%, respectively; P = 0.0063). PBMC and plasma tropism was concordant in 90 patients, and 73 had the R5 strain. Among patients with discordant results, 4 had the R5 virus in their plasma and the X4 virus in PBMCs; 6 showed the opposite profile. Plasma, PBMC, and CSF tropism determinations were concordant in 26/33 patients (21 patients had R5, and 5 had X4). The tropism was discordant in 5/33 patients, with the X4 virus in plasma and R5 in CSF; the HIV tropism in PBMCs was X4 in 3 patients. The remaining 2/33 patients had the R5 virus in plasma and PBMCs and the X4 virus in CSF; one of these patients had a P-RI. The discordant tropism in CSF and blood may have implications for chemokine (C-C motif) receptor 5 (CCR5) antagonist use in patients with limited response to antiretroviral therapy (ART) or in responding patients evaluated for simplification of treatment.

Intraocular and plasma HIV-1 RNA loads and HIV uveitis

OBJECTIVE

The objective of this study was to analyze human immunodeficiency virus (HIV) dynamics across the blood-retinal barrier and to determine whether the high levels of HIV in the eye are associated with any ocular disorders in HIV-infected patients.

DESIGN

This study included a prospective case series of 40 HIV-positive patients with uveitis.

INTERVENTION

Clinical and laboratory examinations included plasma and intraocular HIV-1 RNA loads as well as the clinical manifestations of uveitis.

RESULTS

Intraocular HIV-1 RNA was detected in 32% (13/40) of HIV-positive patients with uveitis. Intraocular HIV-1 RNA loads were associated with high HIV-1 RNA plasma loads (P < 0.001) and not being on HAART therapy (P = 0.005). In addition, detectable intraocular HIV-1 RNA levels were higher in patients with the absence of retinal lesions (P = 0.008). In three patients, the HIV load in the eye largely exceeded that of plasma. These three patients had all bilateral anterior uveitis and/or vitritis without retinal lesions and exhibited no evidence of other intraocular infectious agents causing uveitis than HIV itself.

CONCLUSION

The eye can form a sanctuary where HIV might replicate and cause an inflammatory reaction.

Neurological disease: the effects of HIV and antiretroviral therapy and the implications for early antiretroviral therapy initiation

PURPOSE OF REVIEW

The purpose of this review is to examine the literature regarding HIV-associated neurocognitive disorders, early HIV infection of the central nervous system (CNS), the role of the peripheral immune system in controlling HIV infection and disease within the brain and the potential role that early antiretroviral treatment may play in the preservation of neurocognitive health in patients with more than 500 CD4+ cells/microl.

RECENT FINDINGS

In the post highly active antiretroviral therapy (HAART) era, HIV-associated neurocognitive disorders remain prevalent and even mild-moderate immunosuppression carries a risk for the development of HIV-associated dementia. HIV infection of the CNS occurs early in the illness, and data suggest that a robust peripheral immune system is key to the long-term control of CNS HIV infection. HAART results in clinical, neuropsychological and neuroradiological improvement in patients with HIV-associated neurocognitive disorders, and the prescription of HAART regimens with good cerebrospinal fluid penetration appears to be preferable in this setting. There is little evidence that HAART causes CNS toxicity. The benefits and risks of HAART in the preservation or enhancement of neurocognitive function in well, HIV-infected patients with more than 500 CD4+ cells/microl are unknown.

SUMMARY

The prescription of HAART in well, HIV-infected patients with high CD4+ cell counts may afford enhanced control of CNS HIV infection as a result of the benefits of HAART upon peripheral immune function. In turn, this may result in superior or preserved neurocognitive performance in comparison to the current practice of commencing HAART when CD4+ cells reach 350 cells/microl or lower. This hypothesis will be tested in an upcoming randomized clinical trial.

Compartmentalized human immunodeficiency virus type 1 originates from long-lived cells in some subjects with HIV-1-associated dementia

Human immunodeficiency virus type 1 (HIV-1) invades the central nervous system (CNS) shortly after systemic infection and can result in the subsequent development of HIV-1–associated dementia (HAD) in a subset of infected individuals. Genetically compartmentalized virus in the CNS is associated with HAD, suggesting autonomous viral replication as a factor in the disease process. We examined the source of compartmentalized HIV-1 in the CNS of subjects with HIV-1–associated neurological disease and in asymptomatic subjects who were initiating antiretroviral therapy. The heteroduplex tracking assay (HTA), targeting the variable regions of env, was used to determine which HIV-1 genetic variants in the cerebrospinal fluid (CSF) were compartmentalized and which variants were shared with the blood plasma. We then measured the viral decay kinetics of individual variants after the initiation of antiretroviral therapy. Compartmentalized HIV-1 variants in the CSF of asymptomatic subjects decayed rapidly after the initiation of antiretroviral therapy, with a mean half-life of 1.57 days. Rapid viral decay was also measured for CSF-compartmentalized variants in four HAD subjects (t_1/2 mean = 2.27 days). However, slow viral decay was measured for CSF-compartmentalized variants from an additional four subjects with neurological disease (t_1/2 range = 9.85 days to no initial decay). The slow decay detected for CSF-compartmentalized variants was not associated with poor CNS drug penetration, drug resistant virus in the CSF, or the presence of X4 virus genotypes. We found that the slow decay measured for CSF-compartmentalized variants in subjects with neurological disease was correlated with low peripheral CD4 cell count and reduced CSF pleocytosis. We propose a model in which infiltrating macrophages replace CD4⁺ T cells as the primary source of productive viral replication in the CNS to maintain high viral loads in the CSF in a substantial subset of subjects with HAD.

Infection of the central nervous system (CNS) with human immunodeficiency virus type 1 (HIV-1) can lead to the development of HIV-1–associated dementia, a severe neurological disease that results in cognitive and motor impairment. Individuals that are chronically infected with HIV-1 sometimes display unique viral variants in their cerebrospinal fluid (CSF) that are not detected in the blood virus population, termed CSF-compartmentalized variants. The cell type that produces CSF-compartmentalized virus throughout the course of infection has not been determined. We used a sensitive assay to detect compartmentalized variants in the CSF of subjects with and without neurological disease, and then measured the decay kinetics of compartmentalized virus when subjects were starting antiretroviral therapy. We found that compartmentalized virus decays rapidly in asymptomatic subjects. Additionally, we detected differential decay (i.e. rapid or slow) in subjects with neurological disease, and this was associated with the number of white blood cells in the CSF. Our data supports a model of HIV-1 infection in the CNS where compartmentalized virus is produced by a long-lived cell type (slow decay), and this virus can be amplified by short-lived cells (rapid decay) that traffic into the CNS, but is increasingly produced from long-lived cells in the immunodeficient state.

Neurocognitive function profile in HIV-infected school-age children

OBJECTIVES

Evaluation of neurocognitive function of school-age children with HIV.

DESIGN

Cross-sectional observational study.

METHODS

Twenty-two children (median age 9.46 years) with perinatally acquired HIV infection were administered a global intelligence test and tests from the Amsterdam Neuropsychological Tasks (ANT) program. The relationship between various patient-, disease- and treatment factors and neurocognitive outcome variables was examined.

RESULTS

Compared with age-appropriate norms, mean IQ of the HIV-infected children was in the average range. However, the HIV-infected children performed poorer on several neuropsychological tests compared with age-appropriate norms. Executive function (attentional flexibility, visuospatial working memory) and processing speed emerged as the most sensitive cognitive measures in relation to HIV disease. The correlational analyses resulted in only two significant outcomes, showing that higher CD4% at initiation of highly active antiretroviral therapy (HAART) and longer treatment duration were associated with better working memory function and attentional control, respectively.

CONCLUSIONS

These exploratory data suggest that subtle neurocognitive impairments may exist in HIV-infected school-age children, in particular characterized by compromised executive function and slowed information processing. Further research with larger sample sizes is needed to confirm these findings.

Human immunodeficiency virus-induced uveitis: intraocular and plasma human immunodeficiency virus-1 RNA loads

OBJECTIVE

To report on a human immunodeficiency virus (HIV)-infected patient with uveitis and an intraocular HIV1 RNA load largely exceeding that of plasma and no evidence of other intraocular infectious agents causing uveitis than HIV itself.

DESIGN

Interventional case report.

PARTICIPANT

A 37-year-old male HIV-infected patient with uveitis and no retinal manifestations.

METHODS

Clinical and laboratory examinations including extensive intraocular fluid analyses for various pathogens and HIV-1 RNA loads in the aqueous and plasma.

MAIN OUTCOME MEASURES

Results of aqueous analysis and ophthalmologic features. Correlations between the results of aqueous testing and clinical characteristics.

RESULTS

A 37-year-old patient presented with progressive uveitis. He was positive for HIV-1, and his HIV-1 RNA plasma load was 44,600 copies/mL. His intraocular HIV-1 RNA load was >1,900,000 copies/mL, which largely exceeded his concurrent plasma load. No evidence of infectious agents other than HIV itself was found, and the uveitis reacted promptly to solely the antiretroviral treatment.

CONCLUSIONS

Our findings suggest that HIV can locally replicate within the eye and cause an intraocular inflammatory reaction.

Factors influencing cerebrospinal fluid and plasma HIV-1 RNA detection rate in patients with and without opportunistic neurological disease during the HAART era

Background

In the central nervous system, HIV replication can occur relatively independent of systemic infection, and intrathecal replication of HIV-1 has been observed in patients with HIV-related and opportunistic neurological diseases. The clinical usefulness of HIV-1 RNA detection in the cerebrospinal fluid (CSF) of patients with opportunistic neurological diseases, or the effect of opportunistic diseases on CSF HIV levels in patients under HAART has not been well defined. We quantified CSF and plasma viral load in HIV-infected patients with and without different active opportunistic neurological diseases, determined the characteristics that led to a higher detection rate of HIV RNA in CSF, and compared these two compartments.

Methods

A prospective study was conducted on 90 HIV-infected patients submitted to lumbar puncture as part of a work-up for suspected neurological disease. Seventy-one patients had active neurological diseases while the remaining 19 did not.

Results

HIV-1 RNA was quantified in 90 CSF and 70 plasma samples. The HIV-1 RNA detection rate in CSF was higher in patients with neurological diseases, in those with a CD4 count lower than 200 cells/mm³, and in those not receiving antiretroviral therapy, as well as in patients with detectable plasma HIV-1 RNA. Median viral load was lower in CSF than in plasma in the total population, in patients without neurological diseases, and in patients with toxoplasmic encephalitis, while no significant difference between the two compartments was observed for patients with cryptococcal meningitis and HIV-associated dementia. CSF viral load was lower in patients with cryptococcal meningitis and neurotoxoplasmosis under HAART than in those not receiving HAART.

Conclusion

Detection of HIV-1 RNA in CSF was more frequent in patients with neurological disease, a CD4 count lower than 200 cells/mm³ and detectable plasma HIV-1. Median HIV-1 RNA levels were generally lower in CSF than in plasma but some patients showed higher CSF levels, and no difference between these two compartments was observed in patients with cryptococcal meningitis and HIV-associated dementia, suggesting the presence of intrathecal viral replication in these patients. HAART played a role in the control of CSF HIV levels even in patients with cryptococcal meningitis and neurotoxoplasmosis in whom viral replication is potentially higher.

HIV and Syphilis: When to Perform a Lumbar Puncture

OBJECTIVES

The objectives of this study were to determine predictive factors for neurosyphilis in HIV-infected patients with syphilis and optimize the use of lumbar puncture.

STUDY DESIGN

The authors reviewed 112 cases of HIV-infected patients with syphilis who underwent a lumbar puncture. Diagnosis of neurosyphilis was based on a cerebrospinal fluid white blood cells count > or =20/microL, and/or a reactive cerebrospinal fluid-Venereal Disease Research Laboratory, and/or a positive intrathecal T. pallidum antibody (ITPA) index.

RESULTS

Twenty-six of 112 had neurosyphilis. Neurologic manifestations and serum rapid plasma reagin (RPR) were associated with neurosyphilis (P = 0.036, P = 0.018, respectively). In multivariate analysis, log(2)RPR was still associated with neurosyphilis (P = 0.005). In patients without neurologic manifestations, the risk of neurosyphilis increases gradually with log(2)RPR. A serum RPR of 1/32 seems to be the best cutoff point to decide the performance or not of a lumbar puncture (sensitivity 100%, specificity 40%).

CONCLUSION

In HIV-infected patients with syphilis, lumbar puncture could be restricted to those with neurologic manifestations or a serum RPR > or =1/32.

Viral load determines the B-cell response in the cerebrospinal fluid during human immunodeficiency virus infection

OBJECTIVE

Human immunodeficiency virus (HIV) infection of the central nervous system (CNS) is frequently associated with intrathecal immunoglobulin synthesis and cerebrospinal fluid (CSF) pleocytosis, but little is known about the B-cell response in the CSF of these patients. In this study, we investigated the relation between virus load and the frequency and phenotype of B cells in the CSF of HIV-infected patients.

METHODS

The distribution of T cells, B cells, short-lived plasmablasts, and long-lived plasma cells was analyzed by flow cytometry in CSF and peripheral blood of 33 patients with HIV infection compared with 12 patients with noninfectious CNS diseases. HIV RNA copy number in CSF and serum was quantified by kinetic polymerase chain reaction.

RESULTS

B-cell and plasmablast levels were increased in the CSF of HIV-infected patients compared with patients with noninfectious CNS diseases. Whereas CSF B cells were found at similar frequency during early and late stages of HIV infection, plasmablasts were more prevalent in the CSF during early infection. Plasmablasts in the CSF correlated with intrathecal IgG synthesis and even stronger with HIV RNA copy numbers in CSF, in particular, in untreated, early HIV-infected individuals. Initiation of antiviral treatment in therapy-naive patients strongly decreased HIV copy numbers and plasmablasts in CSF.

INTERPRETATION

Our findings demonstrate that HIV infection of the CNS triggers an early profound B-cell response, with plasmablasts serving as the main virus-related B-cell subset in the CSF.

HIV pharmacology: barriers to the eradication of HIV from the CNS

Total eradication of HIV-1 is not yet achievable, in part because reservoirs of latent HIV-1 can develop within lymphoid tissue, the testes, and the central nervous system (CNS). The presence of HIV-1 in the CNS is clinically significant because of its association with the development of HIV dementia, which occurs in up to one fifth of untreated patients. This review summarizes current theory regarding HIV-1 infection within the CNS, describes physiologic and pharmacologic factors limiting CNS penetration of antiretroviral drugs used to treat HIV-1 infection, and reviews current treatment of CNS HIV-1 infection and HIV encephalopathy.

HIV-producing T cells in cerebrospinal fluid

In HIV-1-infected subjects, the magnitude of HIV-1 viral load in cerebrospinal fluid (CSF) correlates with the CSF white cell count. To determine whether HIV-1-producing T cells appear in CSF and whether their percentage and number correlate with viral load in CSF, we developed a flow cytometric assay that detects HIV-1-producing T cells by identifying intracellular p24 HIV-1 antigen. We found that most CSF T cells were not HIV-1 producing, even when cell-free viral load in CSF was high. Most activated T cells in CSF were also not HIV-1 producing, but the activated CD38+ CD4 T-cell fraction in CSF was independently associated with the fraction of HIV-1-producing T cells in CSF. We conclude that HIV-1-producing T cells appear in CSF and that their percentage and number correlate with cell-free viral load in CSF, even though the CSF total white cell count remains the best predictor for CSF viral load. In HIV-1 infection, CSF white cell counts seem to contain a large number of uninfected cells. White cell counts and viral load in CSF may result from systemic inflammation and immune activation.

Cerebrospinal fluid HIV infection and pleocytosis: relation to systemic infection and antiretroviral treatment

BACKGROUND

Central nervous system (CNS) exposure to HIV is a universal facet of systemic infection. Because of its proximity to and shared barriers with the brain, cerebrospinal fluid (CSF) provides a useful window into and model of human CNS HIV infection.

METHODS

Prospective study of the relationships of CSF to plasma HIV RNA, and the effects of: 1) progression of systemic infection, 2) CSF white blood cell (WBC) count, 3) antiretroviral therapy (ART), and 4) neurological performance. One hundred HIV-infected subjects were cross-sectionally studied, and 28 were followed longitudinally after initiating or changing ART.

RESULTS

In cross-sectional analysis, HIV RNA levels were lower in CSF than plasma (median difference 1.30 log10 copies/mL). CSF HIV viral loads (VLs) correlated strongly with plasma VLs and CSF WBC counts. Higher CSF WBC counts associated with smaller differences between plasma and CSF HIV VL. CSF VL did not correlate with blood CD4 count, but CD4 counts <50 cells/microL associated with a low prevalence of CSF pleocytosis and large differences between plasma and CSF VL. CSF HIV RNA correlated neither with the severity of the AIDS dementia complex (ADC) nor abnormal quantitative neurological performance, although these measures were associated with depression of CD4 counts. In subjects starting ART, those with lower CD4 counts had slower initial viral decay in CSF than in plasma. In all subjects, including five with persistent plasma viremia and four with new-onset ADC, CSF HIV eventually approached or reached the limit of viral detection and CSF pleocytosis resolved.

CONCLUSION

CSF HIV infection is common across the spectrum of infection and is directly related to CSF pleocytosis, though whether the latter is a response to or a contributing cause of CSF infection remains uncertain. Slowing in the rate of CSF response to ART compared to plasma as CD4 counts decline indicates a changing character of CSF infection with systemic immunological progression. Longer-term responses indicate that CSF infection generally responds well to ART, even in the face of systemic virological failure due to drug resistance. We present simple models to explain the differing relationships of CSF to plasma HIV in these settings.

Compartmentalized human immunodeficiency virus type 1 present in cerebrospinal fluid is produced by short-lived cells

Human immunodeficiency virus type 1 (HIV-1) invades the central nervous system (CNS) during primary infection and persists in this compartment by unknown mechanisms over the course of infection. In this study, we examined viral population dynamics in four asymptomatic subjects commencing antiretroviral therapy to characterize cellular sources of HIV-1 in the CNS. The inability to monitor viruses directly in the brain poses a major challenge in studying HIV-1 dynamics in the CNS. Studies of HIV-1 in cerebrospinal fluid (CSF) provide a useful surrogate for the sampling of virus in the CNS, but they are complicated by the fact that infected cells in local CNS tissues and in the periphery contribute to the population pool of HIV-1 in CSF. We utilized heteroduplex tracking assays to differentiate CSF HIV-1 variants that were shared with peripheral blood plasma from those that were compartmentalized in CSF and therefore presumably derived from local CNS tissues. We then tracked the relative decline of individual viral variants during the initial days of antiretroviral therapy. We found that HIV-1 variants compartmentalized in CSF declined rapidly during therapy, with maximum half-lives of approximately 1 to 3 days. These kinetics emulate the decline in HIV-1 produced from short-lived CD4+ T cells in the periphery, suggesting that a similarly short-lived, HIV-infected cell population exists within the CNS. We propose that short-lived CD4+ T cells trafficking between the CNS and the periphery play an important role in amplifying and maintaining HIV-1 populations in the CNS during the asymptomatic phase of infection.

T-cell activation and memory phenotypes in cerebrospinal fluid during HIV infection

We characterized T cell phenotypes in 74 paired blood and cerebrospinal fluid (CSF) samples of HIV-infected and uninfected persons using four-color flow cytometry. CD4+ and CD8+ T cells subsets were further characterized by identifying activated/resting and memory/naive subsets in CSF and blood using the markers CD38/HLA-DR and CD45RA/CD62L, respectively. With and without HIV-infection, the proportion of CD4+ T cells and memory T cells among T cells in CSF was higher compared to blood. In HIV-infection, activated CD4+ and CD8+ T cells in CSF were more abundant than in uninfected controls. As expected, combination antiretroviral therapy (ART) reduced T cell activation in CSF and blood.

Proteomic fingerprinting of human immunodeficiency virus type 1-associated dementia from patient monocyte-derived macrophages: A case study

The emergence of a subset of circulating monocytes during human immunodeficiency virus type 1 (HIV-1) disease has been shown to correlate with cognitive impairment. Thus, it is hypothesized that diagnostic protein profiles may be obtained from these cells from patients with or at risk for HIV-1-associated dementia (HAD). To address this possibility, we used ProteinChip assays to define a unique monocyte-derived macrophage (MDM) protein fingerprint during HAD and whether it is affected by highly active antiretroviral therapy (HAART). The study included five Hispanic women, one with HAD, two HIV-1-infected without cognitive impairment, and two seronegative controls. All patients were matched by age and immune status. Monocytes were recovered from the peripheral blood leukocytes by Percoll gradient centrifugation and allowed to differentiate in vitro for 7 days. Cell lysates and supernatants were collected from the MDM and analyzed by surface enhanced laser desorption/ionization-time of flight ProteinChip assays. Seven unique protein peaks between 3.0 and 20.0 kDa were found in the HAD MDM sample. Each of these proteins were abrogated after HAART. Additional studies extending this one time point determination would serve to confirm the general utility of MDM protein profiling for the diagnosis and monitoring of HAD.

Prevention of AIDS dementia by HAART does not depend on cerebrospinal fluid drug penetrance

The impact of the cerebrospinal fluid (CSF) penetrance properties of different highly active antiretroviral therapy (HAART) regimes on cognitive processing in AIDS dementia is still undetermined. We therefore designed a retrospective cross-sectional and prospective longitudinal analysis of event-related potentials in HIV-infected patients with different combinations of HAART or without antiretroviral treatment. A total of 353 consecutive patients without secondary CNS manifestation of HIV infection were enrolled in the cross-sectional study and 135 consecutive patients without secondary CNS manifestations of HIV infection were enrolled in the longitudinal study. HAART in different combinations (n = 306) or no antiretroviral treatment (n = 47) was given for at least 6 months in the retrospective cross-sectional study. HAART in different combinations (n = 110) or no antiretroviral treatment (n = 25) was given for 1 year in the prospective longitudinal study. We evaluated the latency and amplitude of the P3 component of visually evoked event-related potentials and mean choice reaction time as measures of cognitive processing. Patients receiving HAART had decreased P3 latencies as compared to those patients not receiving HAART but P3 latency and P3 amplitude were not correlated with the amount of CSF penetrance of the different HAART combinations in either statistical analysis. However, mean choice reaction time was significantly correlated with the amount of CSF penetrance. In HIV-infected patients, the CSF penetrance properties of HAART do not have any significant influence on cognitive processing as measured by event-related potentials.

Clinical implications of HIV-1 drug resistance in the neurological compartment

The tropism of human immunodeficiency virus type 1 (HIV-1) for the central nervous system (CNS) develops early during the course of the infection. Potent antiretroviral therapy has been demonstrated to be effective in controlling the replication of HIV-1 in cerebrospinal fluid (CSF), even though a variable response in this compartment compared with that in plasma has been observed. Different concentrations of antiretroviral drugs are found in CSF and the use of antiretroviral drugs penetrating across the blood-brain barrier is considered to be required for controlling CNS infection in advanced patients, particularly in those with neurological disorders. The compartmentalization of HIV-1 infection in the CNS may affect the treatment response, which may cause a different evolution of viral drug resistance in the 2 compartments. Although HIV-1 resistance testing in CSF is not recommended for the routine management of patients with virological failure, treatment decisions in patients with neurological disorders may require knowledge of the resistance profile of the virus in the CSF.

HIV Type 1 replication in cerebrospinal fluid of patients with AIDS-related non-Hodgkin's lymphoma receiving chemotherapy and antiretroviral therapy

Chemotherapy for cancer could have negative effects on HIV-1 dynamic in addition to the effects on immunological status. At the moment few data are available about the effects of chemotherapy on systemic HIV-1 replication, but the effects on the central nervous system, considered an independent compartment for viral replication, has never been investigated. We studied 19 HIV-1-infected patients with non-Hodgkin lymphoma (NHL) treated concomitantly with chemotherapy and highly active antiretroviral therapy (HAART) to evaluate HIV-1 replication and assess virological response to HAART in cerebrospinal fluid during chemotherapy. No patients were diagnosed with lymphoma involvement of the central nervous system. In 18 of 19 patients an HIV-1 load below 200 copies/ml was obtained in cerebrospinal fluid (CSF) during treatment. A correlation between plasma and CSF HIV-1 RNA levels was present at baseline, and was confirmed at the fourth cycle of chemotherapy. A significant decline in the mean difference between plasma and CSF HIV-1 RNA load was observed when comparing the value at the first cycle of chemotherapy with subsequent cycles. HAART even during chemotherapy allows us to obtain an effective control of HIV-1 infection in CSF in patients affected by NHL. In HIV-infected patients with NHL, the contemporaneous administration of HAART and chemotherapy is advisable to obtain a suppression of HIV-1 replication in CNS compartment during the potentially immunosuppressing effect of cancer treatment.

[Cerebrospinal fluid parameters in various stages of HIV infection. Results of cross-sectional and longitudinal analysis]

In up to 50% of all human immunodeficiency virus (HIV) patients, the nervous system is clinically involved. Primary or secondary manifestations of the nervous system have been found in even 90% by neuropathological investigations. We present a retrospective analysis of cerebrospinal fluid (CSF) and serum data of 238 HIV patients. Data of cross-sectional analysis in 208 patients and longitudinal analysis in 30 patients are given. In addition, the viral load in CSF and serum was determined in 29 patients. The HIV patients without opportunistic infections showed increased levels of immunoglobulins and more oligoclonal bands. In later stages of the infection, beta-2 microglobulin as a marker of HIV-associated encephalopathy was increased. In the longitudinal study with an observation period of 1 year, an increase could be observed in total CSF proteins of patients who did not receive antiretroviral treatment. In patients with new opportunistic infections of the central nervous system, similar changes in CSF parameters were noted as in comparison to patients not infected by HIV but with the same opportunistic infections. Analysis of CSF is mandatory for the diagnosis and control of opportunistic infections.

Suppression of cerebrospinal fluid HIV burden in antiretroviral naive patients on a potent four-drug antiretroviral regimen

OBJECTIVE

To determine the longitudinal response of HIV in the cerebrospinal fluid (CSF) to highly active antiretroviral therapy (HAART) and to investigate the levels of indinavir penetrating into the CSF.

DESIGN

Open study of HIV-infected subjects naive to therapy with protease inhibitors.

SETTING

Tertiary care referral center.

SUBJECTS

Twenty-five participants were begun on indinavir, nevirapine, zidovudine, and lamivudine.

INTERVENTIONS

Lumbar punctures were performed prior to therapy and 2 and 6 months after beginning therapy. Plasma and CSF were assayed for routine cell counts, chemistries, HIV load and indinavir levels.

RESULTS

Twenty-two subjects had CSF HIV RNA level data available at all three time points, three others at baseline and 2 months. At month 2 of therapy, nine of 25 (36%) subjects had CSF HIV RNA levels > 50 HIV RNA copies/ml. By 6 months, all 22 subjects had CSF HIV RNA levels < 50 HIV RNA copies/ml. CSF white blood cell counts fell from a baseline mean of 5.3 x 10(6)/l to 1.9 x 10(6)/l (P = 0.013) at 6 months. Plasma indinavir levels declined rapidly while CSF levels remained stable throughout the 8-h dosing interval. The median CSF indinavir level was 71 ng/ml, approximating the upper limit of the 95% inhibitory concentration for indinavir against HIV-1.

CONCLUSIONS

CSF HIV RNA levels cannot be expected to fall below 50 HIV RNA copies/ml even after 2 months of therapy on HAART. Prolonged therapy may be required to suppress HIV levels within the central nervous system.

Clinical implications of CNS penetration of antiretroviral drugs

The CNS serves as an important sanctuary site for HIV replication. The presence of HIV in this compartment may contribute to neurological complications in individuals infected with HIV. Understanding the CNS penetration capabilities of available antiretroviral agents may help clinicians to design treatment regimens with neuroprotective effects. Although numerous clinical studies and anecdotal reports have examined CSF antiretroviral drug exposure as a marker of CNS penetration, understanding the clinical relevance of these findings is difficult. Challenges with study design and subject recruitment often limit the investigator's ability to collect comprehensive data. Upon review of available data, the antiretroviral agents zidovudine, stavudine, lamivudine, nevirapine, efavirenz and indinavir demonstrate consistent penetration into the CSF. Zidovudine-, stavudine-, lamivudine-, didanosine- and protease inhibitor-based regimens also appear to suppress CSF viraemia or improve HIV neurological disease. These agents may be appropriate candidates for neuroprotective antiretroviral treatment regimens. Despite these data, several unanswered questions about the CSF antiretroviral drug exposure-response relationship still remain. Prospective, controlled studies examining this relationship are needed before absolute clinical recommendations are founded.

Factors influencing virological response to antiretroviral drugs in cerebrospinal fluid of advanced HIV-1-infected patients

OBJECTIVE

To determine the effectiveness of antiretroviral therapy in controlling cerebrospinal fluid (CSF) HIV-1 replication and to assess factors related to virological response in advanced patients.

DESIGN

A cross-sectional and longitudinal study.

METHODS

Consecutive paired CSF and plasma samples from HIV-1-infected patients were collected before starting or changing highly active antiretroviral therapy (HAART).

RESULTS

In the cross-sectional analysis 75 patients were included, 55 (73%) with neurological disease, 28 (37%) naive for antiretroviral agents. A significant correlation between plasma and CSF levels at baseline was observed only in antiretroviral-experienced patients. The absence of neurological disease, lower plasma HIV-1 load and a previous exposure to indinavir were all associated with a baseline CSF HIV-1-RNA level less than 80 copies/ml at multivariate analysis. In 29 patients included in the longitudinal study a significant reduction in CSF HIV-1 RNA was observed. Plasma HIV-1-RNA change, CSF HIV-1-RNA level at baseline, overall months of antiretroviral treatment and the magnitude of difference between plasma and CSF HIV-1-RNA levels were all correlated to CSF HIV-1-RNA change during treatment. A significant difference in the magnitude of CSF HIV-1-RNA reduction was observed according to naive status and to the use of three or more drugs penetrating the blood-brain barrier.

CONCLUSION

HAART effectively reduces HIV-1 replication in CSF. A variable response to antiretroviral therapy was observed in CSF, reflecting a different compartmentalization of infection during treatment. Naive status and the use of CNS-penetrating drugs substantially enhance antiviral response. A negative interaction between virological response and the duration of antiretroviral treatment suggests long-term selection of drug-resistant CSF HIV-1 strains.

Impact of highly active antiretroviral therapy on cognitive processing in HIV infection: cross-sectional and longitudinal studies of event-related potentials

Patients with HIV infection often complain of cognitive disturbances, which can be related to AIDS dementia or HIV-associated encephalopathy (HIVE). We investigated the impact of highly active antiretroviral therapy (HAART) in comparison with other therapeutic regimens on the progression of these cognitive disturbances as measured by visual event-related potentials (ERP). In a cross-sectional study, 214 patients without secondary neuromanifestation of their infection were divided into four groups with respect to their treatment status for 1 year before examination: (1) without antiretroviral treatment, (2) zidovudine monotherapy, (3) zidovudine in combination with didanosine, zalcitabine, or lamivudine, and (4) HAART. In a prospective longitudinal study, we divided 54 patients into three groups: (1) without antiretroviral treatment, (2) zidovudine monotherapy, and (3) HAART. Latencies of the P2, N2, and P3 components and the amplitude of the P3 component were evaluated. A significant negative correlation between CD4(+) lymphocyte cell count and P3 latency was found in all patients (p < 0.004). In the cross-sectional study, P3 latency was significantly decreased in the HAART group as compared with patients with no antiretroviral treatment (p < 0.01). During the 1-year period of the prospective longitudinal study, the P3 latency significantly increased in patients with no antiretroviral treatment (p < 0.05) and significantly decreased in patients with HAART (p < 0.05). In summary, these results suggest that HAART has an improving therapeutic effect on cognitive processing in HIV-infected patients and is superior to zidovudine monotherapy or dual antiretroviral treatment. Because prolongation of ERP might in part reflect HIVE, we conclude that this condition represents an indication for HAART.

Differences in the detection of three HIV-1 protease inhibitors in non-blood compartments: clinical correlations

PURPOSE

To study the presence of three HIV-1 protease inhibitors (PIs) in the cerebrospinal fluid (CSF), semen, and lymph nodes and to assess the correlations with residual viral replication in these compartments.

METHOD

We performed a cross-sectional analysis of sanctuary samples from 41 HIV-infected patients on stable highly active antiretroviral therapy (HAART) regimens containing indinavir, nelfinavir, or lopinavir combined with ritonavir (lopinavir/r) and a longitudinal analysis of PI levels and HIV-1 RNA in plasma and CSF of 6 additional patients on nelfinavir or lopinavir/r monotherapy (3 cases each). Plasma, CSF, semen, and a lymph node (LN) biopsy were taken on the same day. Samples were assayed for PI concentrations, HIV-1 RNA levels, and, when detectable, sequencing of the reverse transcriptase and protease genes on seminal viral RNA.

RESULTS

In the cross-sectional analysis, the CSF/plasma ratio was 0.14 for indinavir. Nelfinavir and lopinavir/r were consistently undetectable in CSF. The semen/plasma ratio was 1.9 for indinavir, 0.07 for nelfinavir, and 0.07 for lopinavir. The LN/plasma ratio was 2.07 for indinavir, 0.58 for nelfinavir, 0.21 for lopinavir, and 0.64 for ritonavir. Plasma HIV-1 RNA was <50 copies/mL in 28 patients and was detectable in 13 patients. HIV-1 RNA was <50 copies/mL in CSF samples when plasma RNA was undetectable. Three semen samples taken from patients with viremia <50 copies/mL showed detectable HIV-1 RNA with resistance mutations. HIV-1 RNA was detectable in all LNs, with no differences in patients on indinavir compared with those on nelfinavir or lopinavir/r. In the longitudinal analysis, HIV-1 RNA decreased in the plasma of the 6 patients on nelfinavir or lopinavir/r monotherapy, although CSF HIV-1 RNA decreased only in patients on lopinavir/r.

CONCLUSION

Major differences exist between PIs in terms of detection in non-blood compartments. An undetectable PI level in CSF does not rule out drug activity in the brain for lopinavir/r, although this is not the case for nelfinavir. Poor penetration of PIs in semen in some patients can lead to double nucleoside therapy in this compartment. The persistence of HIV-1 RNA in LNs does not seem to be related to PI levels in this tissue.

Ritonavir induces P-glycoprotein expression, multidrug resistance-associated protein (MRP1) expression, and drug transporter-mediated activity in a human intestinal cell line

The present study characterized the response of P-glycoprotein (P-gp) and multidrug resistance-associated protein (MRP1) to chronic ritonavir (RIT) exposure by assessing increases in P-gp and MRP1 protein expression and activity. LS-180V intestinal carcinoma cells were exposed for 3 days to 1-100 microM RIT concurrently with controls. P-gp and MRP1 protein was quantified by Western blot analysis. Cell accumulation assays, using the P-gp substrate rhodamine 123 (RH123), the P-gp/MRP1 substrate doxorubicin (DOX), and the MRP substrate carboxyfluorescein (CBF), were performed as a measure of transporter activity. RIT strongly induced P-gp and MRP1 expression (maximum 6-fold and 3-fold increases, respectively) in a concentration-dependent fashion. Following extended exposure to RIT (> 10 microM), cells accumulated < 50% of the RH123 and DOX compared with controls, whereas accumulation of CBF was decreased by 30% at 30 microM. Differences in cell accumulation of RH123 could be eliminated with verapamil (100 microM; a P-gp inhibitor), whereas decreased DOX cell accumulation was only partially reversed by verapamil. Indomethacin (100 microM; an MRP1 inhibitor) had no significant effect on RH123 or DOX accumulation, suggesting limited MRP1-mediated activity. Thus, RIT induced protein expression of P-gp and MRP1 and increased cellular drug exclusion of RH123, DOX, and CBF. Similar in vivo phenomena may occur during anti-HIV drug therapy, explaining potential decrements in therapeutic efficacy due to decreases in bioavailability or alterations in drug distribution.

HIV in body fluids during primary HIV infection: implications for pathogenesis, treatment and public health

OBJECTIVE

To describe initial viral dissemination to peripheral tissues and infectious body fluids during human primary HIV infection.

DESIGN

Observational cohort study.

METHODS

Blood plasma, cerebrospinal fluid (CSF), seminal plasma, cervicovaginal lavage fluid and/or saliva were sampled from 17 individuals with primary HIV infection (range of time from symptoms onset to sampling, 8--70 days) and one individual with early infection (168 days). Subjects' HIV-1 RNA levels in each fluid were compared with levels from antiretroviral-naive controls with established HIV infection. For study subjects, correlations were assessed between HIV-1 RNA levels and time from symptoms onset. Responses to antiretroviral therapy with didanosine + stavudine + nevirapine +/- hydroxyurea were assessed in each compartment.

RESULTS

HIV-1 RNA levels were highest closest to symptoms onset in blood plasma (18 patients) and saliva (11 patients). CSF HIV-1 RNA levels (five patients) appeared lower closer to symptoms onset, although they were higher overall in primary versus established infection. Shedding into seminal plasma (eight patients) and cervicovaginal fluid (two patients) was established at levels observed in chronic infection within 3--5 weeks of symptoms onset. High-level seminal plasma shedding was associated with coinfection with other sexually transmitted pathogens. Virus replication was suppressed in all compartments by antiretroviral therapy.

CONCLUSIONS

Peak level HIV replication is established in blood, oropharyngeal tissues and genital tract, but potentially not in CSF, by the time patients are commonly diagnosed with primary HIV infection. Antiretroviral therapy is unlikely to limit initial virus spread to most tissue compartments, but may control genital tract shedding and central nervous system expansion in primary infection.

Concentrations of human immunodeficiency virus type 1 (HIV-1) RNA in cerebrospinal fluid after antiretroviral treatment initiated during primary HIV-1 infection

In 6 patients with primary human immunodeficiency virus type 1 (HIV-1) infection, concentrations of HIV-1 RNA and beta(2)-microglobulin were monitored in cerebrospinal fluid (CSF) and in plasma during antiretroviral therapy. Four patients had neurological symptoms. At baseline, the CSF of 5 patients had detectable levels of HIV-1 RNA (median, 3.68 log(10) copies/mL; range, <2.60-5.67 log(10) copies/mL), and the CSF of 3 patients had elevated levels of beta(2)-microglobulin. After 8 weeks of treatment, the median concentrations of HIV-1 RNA in CSF had decreased to <2.60 log(10) copies/mL (range, <1.60-3.00 log(10) copies/mL; P=.04) and in plasma to 3.07 log(10) copies/mL (range, 2.57-3.79 log(10) copies/mL; P=.03). Median concentration of beta(2)-microglobulin in CSF had decreased to 1.2 mg/L (range, 0.9-1.7 mg/L; P=.06) and, in plasma, to 1.7 mg/L (range, 1.1-2.2 mg/L; P=.03). After 48 weeks, HIV-1 RNA concentrations in 1 patient were still 1.97 log(10) copies/mL in CSF and 1.51 log(10) copies/mL in plasma, although beta(2)-microglobulin concentrations in CSF and plasma had normalized after 8 weeks.

Diagnosis and treatment of HIV-associated neurocognitive disorders

Although significant strides have been made in recent years in treating HIV disease with new antiretroviral medications, the management of neurocognitive disorders continues to remain a challenge. This chapter provides an overview of the current epidemiology, neuropathogenesis, clinical features, diagnosis, and treatment of the central nervous system complications of HIV infection.

Increasing cerebrospinal fluid chemokine concentrations despite undetectable cerebrospinal fluid HIV RNA in HIV-1-infected patients receiving antiretroviral therapy

Only limited data on cerebrospinal fluid (CSF) HIV-1 RNA responses and markers of local inflammation in CSF during antiretroviral therapy are available. HIV-RNA, soluble tumor necrosis factor (TNF)-receptor (sTNFr)-II, monocyte chemoattractant protein (MCP)-1, and interferon-gamma-inducible protein (IP)-10 were measured in the peripheral blood and CSF of 26 antiretroviral-naive HIV-1-positive patients, who were treated with ritonavir (RTV)/saquinavir (SQV) (n = 5), RTV/SQV/stavudine (d4T; n = 8) or zidovudine (AZT)/lamivudine (3TC)/abacavir/nevirapine/indinavir (n = 13). After 8 to 12 weeks of treatment, CSF HIV-RNA dropped to <400 copies/ml in 1 of 5 patients in the RTV/SQV group, 8 of 8 patients in the RTV/SQV/d4T group, and 9 of 10 patients in the five-drug group. CSF sTNFr-II and IP-10 levels increased in patients with detectable CSF HIV-RNA. However, increases in CSF chemokine and sTNFr-II concentrations were also observed in some patients with good CSF HIV-RNA responses. Moreover, CSF MCP-1 concentrations increased in the whole population after 2 months of treatment. Ongoing residual HIV replication in the central nervous system, which cannot be detected with CSF HIV-RNA measurements, may account for this phenomenon.

Enhanced penetration of indinavir in cerebrospinal fluid and semen after the addition of low-dose ritonavir

OBJECTIVE

Penetration of antiretroviral drugs into anatomical HIV-1 reservoirs such as the male genital tract and the central nervous system is important. Data on indinavir (IDV) concentrations in seminal plasma are lacking and IDV concentrations in cerebrospinal fluid are at best borderline.

DESIGN

Thirteen patients were treated with zidovudine (or stavudine), lamivudine, abacavir, nevirapine and IDV (1000 mg three times daily). When nevirapine led to low IDV concentrations, IDV was changed into the combination IDV/ritonavir (RTV) 800/100 mg twice daily to improve the pharmacokinetic profile of IDV.

METHODS

A serum pharmacokinetic profile, a semen sample and a cerebrospinal fluid sample were collected at weeks 8, 24, 48 and 72.

RESULTS

Addition of RTV increased the median IDV trough concentration in serum from 65 to 336 ng/ml (P = 0.005). Median IDV concentration in seminal plasma increased from 141 to 1634 ng/ml (P = 0.002) (n = 9) and in cerebrospinal fluid from 39 (n = 12) to 104 (n = 7) ng/ml (P < 0.001). In six patients with samples collected both before and after the addition of RTV, the IDV concentration in seminal plasma increased 8.2 times [95% confidence interval (CI) 5.2-11.6], and in cerebrospinal fluid 2.4 times (95% CI 1.8-3.9).

CONCLUSIONS

IDV penetrates well into the male genital tract. The addition of low-dose RTV not only increases IDV concentrations in serum but also in seminal plasma and cerebrospinal fluid, thereby probably improving the potency of the regimen in these anatomical HIV reservoirs. Higher serum trough levels alone can not sufficiently explain the observed increases in seminal plasma and cerebrospinal fluid concentrations. Inhibition of P-glycoprotein-mediated transport by RTV might be an additional mechanism.