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

Cerebrospinal Fluid Viral Load Across the Spectrum of Untreated Human Immunodeficiency Virus Type 1 (HIV-1) Infection: A Cross-Sectional Multicenter Study

BACKGROUND

The aim of this large multicenter study was to determine variations in cerebrospinal fluid (CSF) HIV-RNA in different phases of untreated human immunodeficiency virus type 1 (HIV-1) infection and its associations with plasma HIV-RNA and other biomarkers.

METHODS

Treatment naive adults with available CSF HIV-RNA quantification were included and divided into groups representing significant disease phases. Plasma HIV-RNA, CSF white blood cell count (WBC), neopterin, and albumin ratio were included when available.

RESULTS

In total, 1018 patients were included. CSF HIV-RNA was in median (interquartile range [IQR]) 1.03 log10 (0.37-1.86) copies/mL lower than in plasma, and correlated with plasma HIV-RNA (r = 0.44, P < .01), neopterin concentration in CSF (r = 0.49, P < .01) and in serum (r = 0.29, P < .01), CSF WBC (r = 0.34, P < .01) and albumin ratio (r = 0.25, P < .01). CSF HIV-RNA paralleled plasma HIV-RNA in all groups except neuroasymptomatic patients with advanced immunodeficiency (CD4 < 200) and patients with HIV-associated dementia (HAD) or opportunistic central nervous system (CNS) infections. Patients with HAD had the highest CSF HIV-RNA (in median [IQR] 4.73 (3.84-5.35) log10 copies/mL). CSF > plasma discordance was found in 126 of 972 individuals (13%) and varied between groups, from 1% in primary HIV, 11% in neuroasymptomatic groups, up to 30% of patients with HAD.

CONCLUSIONS

Our study confirms previous smaller observations of variations in CSF HIV-RNA in different stages of HIV disease. Overall, CSF HIV-RNA was approximately 1 log10 copies/mL lower in CSF than in plasma, but CSF discordance was found in a substantial minority of subjects, most commonly in patients with HAD, indicating increasing CNS compartmentalization paralleling disease progression.

Dynamic Shifts in the HIV Proviral Landscape During Long Term Combination Antiretroviral Therapy: Implications for Persistence and Control of HIV Infections

Combination antiretroviral therapy (cART) controls but does not eradicate HIV infection; HIV persistence is the principal obstacle to curing infections. The proportion of defective proviruses increases during cART, but the dynamics of this process are not well understood, and a quantitative analysis of how the proviral landscape is reshaped after cART is initiated is critical to understanding how HIV persists. Here, we studied longitudinal samples from HIV infected individuals undergoing long term cART using multiplexed Droplet Digital PCR (ddPCR) approaches to quantify the proportion of deleted proviruses in lymphocytes. In most individuals undergoing cART, HIV proviruses that contain gag are lost more quickly than those that lack gag. Increases in the fraction of gag-deleted proviruses occurred only after 1–2 years of therapy, suggesting that the immune system, and/or toxicity of viral re-activation helps to gradually shape the proviral landscape. After 10–15 years on therapy, there were as many as 3.5–5 times more proviruses in which gag was deleted or highly defective than those containing intact gag. We developed a provirus-specific ddPCR approach to quantify individual clones. Investigation of a clone of cells containing a deleted HIV provirus integrated in the HORMAD2 gene revealed that the cells underwent a massive expansion shortly after cART was initiated until the clone, which was primarily in effector memory cells, dominated the population of proviruses for over 6 years. The expansion of this HIV-infected clone had substantial effects on the overall proviral population.

The cerebrospinal fluid HIV risk score for assessing central nervous system activity in persons with HIV

Detectable human immunodeficiency virus (HIV) RNA in the cerebrospinal fluid (CSF) is associated with central nervous system (CNS) complications. We developed the CSF HIV risk score through prediction modeling to estimate the risk of detectable CSF HIV RNA (threshold >50 copies/mL) to help identify persons who might benefit most from CSF monitoring. We used baseline data from 1,053 participants receiving combination antiretroviral therapy who were enrolled in the 6-center, US-based CNS HIV Antiretroviral Therapy Effects Research (CHARTER) prospective cohort in 2004-2007. Plasma HIV RNA, CNS penetration effectiveness, duration of combination antiretroviral therapy, medication adherence, race, and depression status were retained correlates of CSF HIV RNA, displaying good discrimination (C statistic = 0.90, 95% confidence interval (CI): 0.87, 0.93) and calibration (Hosmer-Lemeshow P = 0.85). The CSF HIV risk score ranges from 0 to 42 points, with a mean of 15.4 (standard deviation, 7.3) points. At risk scores greater than 25, the probability of detecting CSF HIV RNA was at least 42.9% (95% CI: 36.6, 49.6). For each 1-point increase, the odds of detecting CSF HIV RNA increased by 26% (odds ratio = 1.26, 95% CI: 1.21, 1.31; P < 0.01). The risk score correlates with detection of CSF HIV RNA. It represents an advance in HIV management and monitoring of CNS effects, providing a potentially useful tool for clinicians.

CSF penetration by antiretroviral drugs

Severe HIV-associated neurocognitive disorders (HAND), such as HIV-associated dementia, and opportunistic CNS infections are now rare complications of HIV infection due to comprehensive highly active antiretroviral therapy (HAART). By contrast, mild to moderate neurocognitive disorders remain prevalent, despite good viral control in peripheral compartments. HIV infection seems to provoke chronic CNS injury that may evade systemic HAART. Penetration of antiretroviral drugs across the blood-brain barrier might be crucial for the treatment of HAND. This review identifies and evaluates the available clinical evidence on CSF penetration properties of antiretroviral drugs, addressing methodological issues and discussing the clinical relevance of drug concentration assessment. Although a substantial number of studies examined CSF concentrations of antiretroviral drugs, there is a need for adequate, well designed trials to provide more valid drug distribution profiles. Neuropsychological benefits and neurotoxicity of potentially CNS-active drugs require further investigation before penetration characteristics will regularly influence therapeutic strategies and outcome.

Virological Response in Cerebrospinal Fluid to Antiretroviral Therapy in a Large Italian Cohort of HIV-Infected Patients with Neurological Disorders

The aim of the present study was to analyse the effect of antiretroviral (ARV) therapy and single antiretroviral drugs on cerebrospinal fluid (CSF) HIV-RNA burden in HIV-infected patients affected by neurological disorders enrolled in a multicentric Italian cohort. ARVs were considered “neuroactive” from literature reports. Three hundred sixty-three HIV-positive patients with available data from paired plasma and CSF samples, were selected. One hundred twenty patients (33.1%) were taking ARVs at diagnosis of neurological disorder. Mean CSF HIV-RNA was significantly higher in naïve than in experienced patients, and in patients not taking ARV than in those on ARV. A linear correlation between CSF HIV-RNA levels and number of neuroactive drugs included in the regimen was also found (r = −0.44, P < 0.001). Low -plasma HIV-RNA and the lack of neurocognitive impairment resulted in independently associated to undetectable HIV-RNA. Taking nevirapine or efavirenz, or regimen including NNRTI, NNRTI plus PI or boosted PI, was independently associated to an increased probability to have undetectable HIV-RNA in CSF. The inclusion of two or three neuroactive drugs in the ARV regimen was independently associated to undetectable viral load in CSF. Our data could be helpful in identifying ARV regimens able to better control HIV replication in the CNS sanctuary, and could be a historical reference for further analyses.

Changes in cognition during antiretroviral therapy: comparison of 2 different ranking systems to measure antiretroviral drug efficacy on HIV-associated neurocognitive disorders

OBJECTIVE

Although HIV-associated neurocognitive disorders should be treated with highly active antiretroviral treatment (HAART) regimens with good central nervous system (CNS) penetration, the definition of neuroactive HAART remains controversial. We compared 2 ranking systems to measure HAART neuroeffectiveness.

METHODS

Patients with (n = 93) or at risk for (n = 92) HIV-associated neurocognitive disorders underwent neuropsychological (NP) test batteries before HAART initiation and at follow-up. Changes in normatively adjusted summary NP test z scores were calculated for each subject. Two neuropenetration scores were calculated: the central nervous system penetration reference score (number of drugs in the combination among zidovudine, abacavir, stavudine, lamivudine, efavirenz, nevirapine, indinavir, and lopinavir-ritonavir) and the CNS penetration-effectiveness (CPE) score: a summary score of 1 (high: penetration: [corrected] zidovudine, abacavir, delavirdine, [corrected] nevirapine, amprenavir-ritonavir, fosamprenavir-ritonavir, [corrected] indinavir-ritonavir, and lopinavir-ritonavir), 0.5 (intermediate penetration: [corrected] stavudine, lamivudine, emtricitabine, efavirenz, amprenavir, fosamprenavir, [corrected] atazanavir-ritonavir, atazanavir, [corrected] and indinavir), and 0 (low penetration: remaining ARVs) [corrected] for each drug in the combination. Main outcome measures were changes in global NPZ scores and in summary z scores on 5 domains.

RESULTS

At regression analyses, higher CPE scores correlated with greater improvements in NPZ-4 (P = 0.0283), NPZ-8 (P = 0.0071), concentration and speed of mental processing (P = 0.0046), and mental flexibility (P = 0.0262) summary z scores. The correlation was stronger among NP-impaired patients. By contrast, higher estimates of neuroeffectiveness with the alternative system showed no correlation. No association was seen between CD4 and plasma viral load changes with both scores.

CONCLUSIONS

The CPE score represents a step forward toward the identification of a clinically useful approach to estimating HAART ability to improve cognition.

Darunavir concentrations in cerebrospinal fluid and blood in HIV-1-infected individuals

Darunavir is the most recently licensed protease inhibitor currently used in treatment-experienced HIV-infected individuals. Our objective was to determine darunavir concentrations in cerebrospinal fluid (CSF) and plasma in subjects receiving antiretroviral treatment regimens containing ritonavir-boosted darunavir. Darunavir concentrations were determined by liquid chromatography tandem mass spectrometry in 14 paired CSF and plasma samples from eight HIV-1-infected individuals. The lower limit of quantification was 5.0 ng/ml. All of the 14 CSF samples had detectable darunavir concentrations with a median darunavir concentration of 34.2 ng/ml (range 15.9-212.0 ng/ml). The median (range) plasma darunavir concentration was 3930 (1800-12900) ng/ml. All CSF samples had detectable darunavir concentrations. Most of them exceeded or were in the same range as levels needed to inhibit replication of wild type virus, making it probable that darunavir, at least to some extent, contributes to the suppression of HIV replication in the central nervous system.

Pharmaceutical approaches to eradication of persistent HIV infection

Highly active antiretroviral therapy (HAART) has markedly decreased morbidity and mortality in human immunodeficiency virus type 1 (HIV-1)-infected individuals in the developed world. Successful therapy often results in stable plasma levels of HIV-1 RNA below the limits of detection of commercial assays. Nonetheless, HIV-1 has not been cured by HAART. The causes of persistence of HIV infection in the face of current therapy appear to be multifactorial: latent but replication-competent provirus in resting CD4+ T cells, cryptic viral expression below the limits of detection of clinical assays, and viral sanctuary sites might all contribute to persistence. Clearance of HIV infection will almost certainly require a multimodality approach that includes potent suppression of HIV replication, therapies that reach all compartments of residual HIV replication and depletion of any reservoirs of persistent, quiescent proviral infection. This review highlights the basic mechanisms for the establishment and maintenance of viral reservoirs and pharmaceutical approaches towards their elimination.

Antiretroviral therapy and central nervous system HIV type 1 infection

Central nervous system (CNS) human immunodeficiency virus type 1 (HIV-1) infection begins during primary viremia and continues throughout the course of untreated systemic infection. Although frequently accompanied by local inflammatory reactions detectable in cerebrospinal fluid (CSF), CNS HIV-1 infection usually is not clinically apparent. In a minority of patients, CNS HIV-1 infection evolves into encephalitis during the late stages of systemic infection, which compromises brain function and presents clinically as acquired immunodeficiency syndrome dementia complex (ADC). Combination antiretroviral therapy (ART) has had a major impact on all aspects of CNS HIV-1 infection and disease. In those with asymptomatic infection, ART usually effectively suppresses HIV-1 in CSF and markedly reduces the incidence of symptomatic ADC. In those presenting with ADC, ART characteristically prevents neurological progression and leads to variable, and at times substantial, recovery. Similarly, treatment has reduced CNS opportunistic infections. With better control of these severe disorders, attention has turned to the possible consequences of chronic silent infection and the issue of whether indolent, low-grade brain injury might require earlier treatment intervention.

Antiretroviral treatment effect on immune activation reduces cerebrospinal fluid HIV-1 infection

OBJECTIVE

To define the effect of antiretroviral therapy (ART) on activation of T cells in cerebrospinal fluid (CSF) and blood, and interactions of this activation with CSF HIV-1 RNA concentrations.

DESIGN

Cross-sectional analysis of 14 HIV-negative subjects and 123 neuroasymptomatic HIV-1-infected subjects divided into 3 groups: not on ART (termed "offs"), on ART with plasma HIV-1 RNA >500 copies/mL ("failures"), and on ART with plasma HIV-1 RNA <or=500 copies/mL ("successes"). T-cell activation was measured by coexpression of CD38 and human leukocyte antigen DR (HLA-DR). Other measurements included CSF neopterin and white blood cell (WBC) counts.

RESULTS

CD8 T-cell activation in CSF and blood was highly correlated across all subjects and was highest in the offs, lower in the failures, and lower still in the successes. While CD8 activation was reduced in failures compared to offs across the range of plasma HIV-1, it maintained a coincident relation to CSF HIV-1 in both viremic groups. In addition to correlation with CSF HIV-1 concentrations, CD8 activation in blood and CSF correlated with CSF WBCs and CSF neopterin. Multivariate analysis confirmed the association of blood CD8 T-cell activation, along with plasma HIV-1 RNA and CSF neopterin, with CSF HIV-1 RNA levels.

CONCLUSIONS

The similarity of CD8 T-cell activation in blood and CSF suggests these cells move from blood to CSF with only minor changes in CD38/HLA-DR expression. Differences in the relation of CD8 activation to HIV-1 concentrations in the blood and CSF in the 2 viremic groups suggest that changes in immune activation not only modulate CSF HIV-1 replication but also contribute to CSF treatment effects. The magnitude of systemic HIV-1 infection and intrathecal macrophage activation are also important determinants of CSF HIV-1 RNA levels.

HIV-1 RNA concentration and cognitive performance in a cohort of HIV-positive people

OBJECTIVE

To determine whether higher viral concentrations in the cerebrospinal fluid (CSF) and/or peripheral blood were associated with greater severity of cognitive impairment in HIV-1-seropositive subjects with cognitive-motor impairment.

METHODS

Cognitive performance measurements and viral load were obtained from HIV-1-seropositive individuals with cognitive-motor impairment entering a clinical trial before the introduction of highly active antiretroviral therapy (HAART). CSF viral load (UltraSensitive Roche HIV-1 Monitor test with detection limit of 50 copies/ml) was available from 179 patients, and peripheral (plasma or serum) viral load from 111 patients. Of these patients, 62% met the 1993 Centers for Disease Control (CDC) criteria for AIDS, and 19% had clinically significant cognitive impairment (i.e., global deficit score > or = 0.5). Possible associations between viral load and cognitive scores were examined with general linear regression models with and without adjustment for age, education, study site, antiretroviral use, CD4 cell count, and CDC stage.

RESULTS

The mean CSF viral load was 2.83 log(10)/ml +/- 0.94 (SD) (undetectable in 19.5%). Mean peripheral viral load was 4.11 log(10)/ml +/- 0.90 (SD). No statistically significant associations emerged between either CSF or peripheral viral load and the global deficit score, or any of the seven cognitive domain deficit scores.

CONCLUSIONS

Among these HIV-1-sero-positive individuals with mainly minor HIV-1-associated cognitive deficits and not receiving HAART, no association between CSF or blood concentration of HIV-1 RNA and cognitive performance could be found. These results suggest that the severity of HIV-1-associated cognitive impairment is not directly related to concurrent viral concentration in the CSF or the peripheral blood.

Inhibition of P-glycoprotein activity at the primate blood-brain barrier increases the distribution of nelfinavir into the brain but not into the cerebrospinal fluid

P-glycoprotein (P-gp) expression at the rodent blood-brain barrier (BBB) limits the central nervous system (CNS) distribution of anti-human immunodeficiency virus (HIV) protease inhibitors (PIs). However, it is not clear whether P-gp activity at the human BBB is as effective as that in rodents in preventing the distribution of PIs into the CNS. If it is, inhibition of P-gp at the human BBB could increase the distribution of the PIs into the CNS and, therefore, their efficacy against HIV-associated dementia. Because the distribution of the PIs into the human brain cannot be directly measured, we conducted studies in a more representative animal, the nonhuman primate. Specifically we investigated the distribution of nelfinavir (a PI and a P-gp substrate; 6 mg/kg i.v.) into the brain and cerebrospinal fluid (CSF) of nonhuman primates (cynomolgus monkeys, Macaca fascicularis) in the presence and absence of the potent and selective P-gp inhibitor, zosuquidar, and whether changes in brain nelfinavir concentration, after inhibition of P-gp, paralleled those in the CSF. Our data indicate that nelfinavir has poor penetration into the macaque's brain and CSF, and P-gp inhibition at the BBB by zosuquidar enhanced the distribution of nelfinavir into the brain by 146-fold. However, the concentration of nelfinavir in the CSF was unaffected by coadministration of zosuquidar (p > 0.05). In conclusion, P-gp inhibition at the nonhuman primate BBB significantly enhanced the distribution of nelfinavir into the brain, and this effect was not observed in the CSF. Therefore, as is common in human studies investigating P-gp inhibition at the BBB, CSF concentration of a drug should not be used as a surrogate marker for brain drug concentration.

HIV-1 RNA levels in cerebrospinal fluid and plasma and their correlation with opportunistic neurological diseases in a Brazilian AIDS reference hospital

BACKGROUND: Plasma HIV RNA levels reflect systemic viral replication but in CNS it may occur relatively independent of systemic infection, yet clinical application of CSF HIV-1 RNA levels is less clear. OBJECTIVE: to compare CSF and plasma HIV-1 RNA levels of patients with different opportunistic neurological diseases to those without neurological disease, as well as to correlate these levels with the outcome of the disease and use of HAART. METHOD: 97 patients who had lumbar puncture for routine work up of suspected neurological diseases, were divided in 2 groups: without neurological disease (23) and with neurological disease (74). NASBA was used for plasma and CSF HIV RNA. RESULTS: Median CSF viral load was higher in toxoplasmic encephalitis, cryptococcal meningitis, HIV dementia and neurological diseases without a defined etiology when compared to patients without neurological disease. There was no difference between plasma viral load in patients with and without neurological diseases. Median viral load was higher in plasma and CSF among patients who died when compared to those successfully treated. CSF and plasma viral load were lower in patients with opportunistic diseases on HAART than without HAART. CONCLUSION: CSF viral load was higher in patients with any neurological disease, but this difference was not present in plasma viral load, suggesting that neurological disease influences more the CSF than plasma compartments. Notwithstanding different neurological diseases were not possible to be diferentiated by the levels of CSF HIV-1.

Efficacy of cerebrospinal fluid (CSF)-penetrating antiretroviral drugs against HIV in the neurological compartment: different patterns of phenotypic resistance in CSF and plasma

BACKGROUND

Cerebrospinal fluid (CSF) concentrations of multiple drugs in a large human immunodeficiency virus (HIV)-infected patient population, the virtual phenotype profiles for HIV in the plasma and CSF compartments, and the correlation of these profiles with exposure to antiretroviral therapy need to be further investigated.

METHODS

Drug concentrations in CSF and plasma were concomitantly determined for a large group of HIV-infected individuals receiving highly active antiretroviral therapy (HAART). Samples were analyzed using a validated method consisting of liquid chromatography with mass spectrometry. For patients with detectable levels of virus, genotypic analysis was performed, followed by a virtual phenotype study.

RESULTS

Sixty-three HIV-infected patients were included in the study, 78% of whom were affected by neurological disease. Drug concentrations in CSF specimens were undetectable for didanosine, efavirenz, nelfinavir, and concomitantly administered ritonavir and saquinavir. CSF concentrations were higher for nevirapine, with a median CSF-to-plasma concentration ratio of 0.63, followed by lamivudine (0.23), stavudine (0.20), and indinavir (0.11). In 18 of the 40 patients with virtual phenotype data available for virus recovered from CSF samples and from plasma samples, differences in fold-change of resistance between the CSF virus and the plasma virus were noted for at least 1 drug. Factors associated with having differences in fold-change of resistance were number of drugs to which the patient had been exposed (P=.02) and presence of neurological disease (P=.05). A significant association was found between duration of therapy and fold-change of resistance in CSF and plasma isolates.

CONCLUSIONS

Antiretrovirals have different levels of penetration in the CSF, with several drugs achieving only low CSF concentrations. CSF isolates have different resistance profiles than do plasma isolates. Effective treatment decisions for CSF manifestations of disease may require better knowledge of drug penetration and the drug susceptibility of HIV in the CSF.

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.

Cerebrospinal Fluid HIV-1 Infection Usually Responds Well to Antiretroviral Treatment

The primary objective of this retrospective study was to determine how many patients in routine practice who were treated with combination antiretroviral treatment reached HIV-1 RNA levels below 50–400 copies/ml in cerebrospinal fluid (CSF). Seventy-four antiretroviral-naive HIV-1-infected patients from five different centres in Germany, Italy, Sweden and the USA were included. Thirty-nine percent of the patients had a HIV-1-associated neurological disease and 53% of the patients had AIDS. HIV-1 RNA in CSF and plasma were quantified before and after approximately 3 months of treatment. At baseline, the median value of HIV-1 RNA in CSF was 4.12 log copies/ml (interquartile range (IQR): 3.28–4.85) and it decreased to <1.70 log copies/ml (IQR: <1.70–2.48; P<0.001) after in median 3 months of treatment. Seventy-six percent of the patients had HIV-1 RNA levels below the limits of detection in CSF at follow-up, and 85% reached below 400 copies/ml. In plasma, 45% of the patients had levels of HIV-1 RNA below the limits of detection at follow-up and 80% reached below 400 copies/ml. The group of patients with a neurological disease had a significantly higher CSF viral load both at baseline and at follow-up compared with the neurologically asymptomatic patients. We conclude that the central nervous system (CNS) is usually not a ‘sanctuary site’, difficult to reach with combination anti-retroviral treatment.