Viral co-infection, autoimmunity, and CSF HIV antibody profiles in HIV central nervous system escape.

Antiretroviral therapy (ART) suppresses plasma and cerebrospinal fluid (CSF) HIV replication. Neurosymptomatic (NS) CSF escape is a rare exception in which CNS HIV replication occurs in the setting of neurologic impairment. The origins of NS escape are not fully understood. We performed a case-control study of asymptomatic (AS) escape and NS escape subjects with HIV-negative subjects as controls in which we investigated differential immunoreactivity to self-antigens in the CSF of NS escape by employing neuroanatomic CSF immunostaining and massively multiplexed self-antigen serology (PhIP-Seq). Additionally, we utilized pan-viral serology (VirScan) to deeply profile the CSF anti-viral antibody response and metagenomic next-generation sequencing (mNGS) for pathogen detection. We detected Epstein-Barr virus (EBV) DNA more frequently in the CSF of NS escape subjects than in AS escape subjects. Based on immunostaining and PhIP-Seq, there was evidence for increased immunoreactivity against self-antigens in NS escape CSF. Finally, VirScan revealed several immunodominant epitopes that map to the HIV envelope and gag proteins in the CSF of AS and NS escape subjects. Whether these additional inflammatory markers are byproducts of an HIV-driven process or whether they independently contribute to the neuropathogenesis of NS escape will require further study.

Factors associated with neurocognitive test performance at baseline: a substudy of the INSIGHT Strategic Timing of AntiRetroviral Treatment (START) trial.

OBJECTIVES: We describe neuropsychological test performance (NP) in antiretroviral treatment (ART)-naïve HIV-positive individuals with CD4 cell counts above 500 cells/µL. METHODS: In a neurology substudy of the International Network for Strategic Initiatives in Global HIV Trials (INSIGHT) Strategic Timing of AntiRetroviral Treatment (START) study, eight neurocognitive tests were administered. The primary measure of NP was the quantitative NP z-score (QNPZ-8), the average of the z-scores for the eight tests. Associations of baseline factors with QNPZ-8 scores were assessed by multiple regression. Mild neurocognitive impairment (NCI) was defined as z-scores < -1 in at least two of six cognitive domains. RESULTS: A total of 608 participants had a median age of 34 years; 11% were women and 15% were black; the median time since HIV diagnosis was 0.9 years; the median CD4 cell count was 633 cells/µL; 19.9% had mild NCI. Better NP was independently associated with younger age, being white, higher body mass index (0.10 per 10 kg/m(2) higher), and higher haematocrit percentage (0.19 per 10% higher). Worse NP was associated with longer time since HIV diagnosis (-0.17 per 10 years), diabetes (-0.29) and higher Framingham risk score (-0.15 per 10 points higher). QNPZ-8 scores differed significantly between geographical locations, with the lowest scores in Brazil and Argentina/Chile. CONCLUSIONS: This is the largest study of NP in ART-naïve HIV-positive adults with CD4 counts > 500 cells/µL. Demographic factors and diabetes were most strongly associated with NP. Unmeasured educational/sociocultural factors may explain geographical differences. Poorer NP was independently associated with longer time since HIV diagnosis, suggesting that untreated HIV infection might deleteriously affect NP, but the effect was small.

Cardiovascular risk factors associated with lower baseline cognitive performance in HIV-positive persons.

OBJECTIVE: To determine factors associated with baseline neurocognitive performance in HIV-infected participants enrolled in the Strategies for Management of Antiretroviral Therapy (SMART) neurology substudy. METHODS: Participants from Australia, North America, Brazil, and Thailand were administered a 5-test neurocognitive battery. Z scores and the neurocognitive performance outcome measure, the quantitative neurocognitive performance z score (QNPZ-5), were calculated using US norms. Neurocognitive impairment was defined as z scores <-2 in two or more cognitive domains. Associations of test scores, the QNPZ-5, and impairment with baseline factors including demographics and risk factors for HIV-associated dementia (HAD) and cardiovascular disease (CVD) were determined in multiple regression. RESULTS: The 292 participants had a median CD4 cell count of 536 cells/mm(3), 88% had an HIV viral load < or =400 copies/mL, and 92% were taking antiretrovirals. Demographics, HIV, and clinical factors differed between locations. The mean QNPZ-5 score was -0.72; 14% of participants had neurocognitive impairment. For most tests, scores and z scores differed significantly between locations, with and without adjustment for age, sex, education, and race. Prior CVD was associated with neurocognitive impairment. Prior CVD, hypercholesterolemia, and hypertension were associated with poorer neurocognitive performance but conventional HAD risk factors and the CNS penetration effectiveness rank of antiretroviral regimens were not. CONCLUSIONS: In this HIV-positive population with high CD4 cell counts, neurocognitive impairment was associated with prior CVD. Lower neurocognitive performance was associated with prior CVD, hypertension, and hypercholesterolemia, but not conventional HAD risk factors. The contribution of CVD and cardiovascular risk factors to the neurocognition of HIV-positive populations warrants further investigation.

Failure of atorvastatin to modulate CSF HIV-1 infection: results of a pilot study.

BACKGROUND: HIV-1 infection of the CSF space is nearly universal in untreated systemic infection, and correlates strongly with intrathecal and systemic immunoactivation and CSF pleocytosis. Based on the potential immunomodulatory and antiviral properties of HMG-CoA reductase inhibitors (statins), we examined the effect of atorvastatin on CSF HIV-1 infection and associated CSF abnormalities in a small pilot study. METHODS: Seven male HIV-1-infected, antiretroviral-naïve subjects with a mean blood CD4+ T cell count of 473 cells/muL were studied in an open-label, single-arm pilot study to assess the effects of 80 mg atorvastatin daily for 8 weeks. The primary endpoint was the change in CSF HIV-1 RNA levels, both absolutely and relative to plasma HIV-1 RNA, at 4 and 8 weeks of treatment. Other outcome measures included CSF white blood cell counts and neopterin concentrations as indices of intrathecal immunoactivation, and blood HIV-1 RNA levels, neopterin concentrations, and T lymphocyte counts. Effects on blood lipids were used to monitor the established biologic effects of atorvastatin and treatment adherence. RESULTS: No significant changes in CSF virologic and inflammatory indices or in systemic HIV-1 infection were observed during atorvastatin treatment despite potent reduction of blood lipids. CONCLUSION: Atorvastatin showed no appreciable effect on CSF HIV-1 infection or intrathecal immunoactivation in this small uncontrolled study and thus appears to have little promise as an immunomodulatory adjuvant therapy for CNS HIV-1 infection, at least in neuroasymptomatic subjects with preserved CD4+ T cell counts.

Biomarkers of HIV-1 CNS infection and injury.

While it is clear that HIV-1 can cause CNS dysfunction, current approaches to classification and diagnosis of this dysfunction rely on syndromic definitions or measures of abnormality on neuropsychological testing in the background context of HIV-1 infection. These definitions have been variably applied, offer only limited sensitivity or specificity, and do not easily distinguish active from static brain injury. Supplanting or augmenting these approaches with objective biologic measurements related to underlying disease processes would provide a major advance in classification, diagnosis, epidemiology, and treatment assessment. Two major avenues are now actively pursued to this end: 1) analysis of soluble molecular markers in CSF and, to a lesser degree, in blood, and 2) neuroimaging markers using anatomic, metabolic, and functional measurements. This review considers the rationale and prospects of these approaches.

Updated research nosology for HIV-associated neurocognitive disorders.

In 1991, the AIDS Task Force of the American Academy of Neurology published nomenclature and research case definitions to guide the diagnosis of neurologic manifestations of HIV-1 infection. Now, 16 years later, the National Institute of Mental Health and the National Institute of Neurological Diseases and Stroke have charged a working group to critically review the adequacy and utility of these definitional criteria and to identify aspects that require updating. This report represents a majority view, and unanimity was not reached on all points. It reviews our collective experience with HIV-associated neurocognitive disorders (HAND), particularly since the advent of highly active antiretroviral treatment, and their definitional criteria; discusses the impact of comorbidities; and suggests inclusion of the term asymptomatic neurocognitive impairment to categorize individuals with subclinical impairment. An algorithm is proposed to assist in standardized diagnostic classification of HAND.

Antiretroviral treatment reduces increased CSF neurofilament protein (NFL) in HIV-1 infection.

OBJECTIVE: Increased levels of the light-chain neurofilament protein (NFL) in CSF provide a marker of CNS injury in several neurodegenerative disorders and have been reported in the AIDS dementia complex (ADC). We examined the effects of highly active antiretroviral treatment (HAART) on CSF NFL in HIV-1-infected subjects with and without ADC who underwent repeated lumbar punctures (LPs). METHOD: NFL was measured by ELISA (normal reference value < 250 ng/L) in archived CSF samples from 53 patients who had undergone LPs before and after initiation of HAART. RESULTS: Twenty-one of the subjects had increased CSF NFL at baseline, with a median level of 780 ng/L and an intraquartile range (IQR) of 480 to 7300. After 3 months of treatment, NFL concentrations had fallen to normal in 48% (10/21), and the median decreased to 340 ng/L (IQR < 250 to 4070) (p < 0.001), whereas at 1 year, only 4 of 16 of the 21 subjects observed for this length still had elevated NFL levels. Thirty-two subjects had normal NFL at baseline, and all but one remained normal at follow-up. These effects on CSF NFL were seen in association with clinical improvement in ADC patients, decreases in plasma and CSF HIV-1 RNA and CSF neopterin, and increases in blood CD4 T cell counts. CONCLUSION: HAART seems to halt the neurodegenerative process(es) caused by HIV-1, as shown by the significant decrease in CSF NFL after treatment initiation. CSF NFL may serve as a useful marker in monitoring CNS injury in HIV-1 infection and in evaluating CNS efficacy of antiretroviral therapy.

Cerebrospinal fluid response to structured treatment interruption after virological failure.

OBJECTIVE: Structured antiretroviral treatment interruption (STI) has been advocated as a therapeutic strategy for HIV-1 infection. We report initial observations of cerebrospinal fluid (CSF) HIV-1 infection in five patients undergoing serial lumbar punctures (LPs) during STI undertaken following virological failure. DESIGN AND METHODS: In this prospective observational study we quantified HIV-1 RNA concentrations and assessed both phenotypic drug susceptibility profiles and genotypic antiviral drug resistance mutations in CSF and plasma during the period of treatment interruption. CSF white blood cells were also counted, and patients' neurological status monitored. RESULTS: In four of the patients, CSF HIV-1 concentration increased more rapidly than that of the plasma, with consequent reduction in the ratio between plasma and CSF viral loads (pVL : cVL). Three individuals developed robust, though asymptomatic CSF lymphocytic pleocytosis. In all patients the predominant HIV-1 quasispecies shifted simultaneously in CSF and plasma from a drug-resistant to a more drug-susceptible phenotype with identical and simultaneous changes in genotypes associated with drug resistance. CONCLUSIONS: STI may be accompanied by previously unrecognized changes in tissue viral exposures and lymphocyte traffic. Hence, despite 'virological failure' as evidenced by persistent plasma viremia, ongoing antiretroviral treatment prior to its interruption appeared to suppress CSF HIV-1 infection (indeed more effectively than that of plasma) and restrain lymphocyte traffic into the CSF. Simultaneous change of resistance mutations in CSF and plasma was likely due to re-emergence and overgrowth of pre-existing strains with ready exchange of virus between these two compartments, either facilitated by or provoking a local CSF lymphocytosis.

HIV-1 reverse transcriptase sequence in plasma and cerebrospinal fluid of patients with AIDS dementia complex treated with Abacavir.

OBJECTIVE: To assess HIV-1 RNA levels and the relationship between HIV-1 reverse transcriptase (RT) genotype from plasma and cerebrospinal fluid (CSF) during treatment with abacavir (Ziagen, ABC) or placebo in combination with stable background therapy (SBG) in subjects with AIDS dementia complex (ADC) (study CNA3001). DESIGN: One-hundred and five HIV-1 infected adults with ADC were randomized to receive either ABC (600 mg twice daily) or ABC-matched placebo (twice daily) in addition to SBG for 12 weeks. METHODS: Plasma and CSF were collected for population sequencing at baseline and week 12 (CSF optional). Sequences were analyzed for mutations associated with resistance to nucleoside reverse transcriptase inhibitors (NRTI). RESULTS: Sixty out of sixty-seven subjects with baseline plasma HIV-RT sequence data harbored virus with > or = 1 NRTI-associated mutations; 50 out of 67 had the M184V mutation. At week 12, more subjects in the ABC group had plasma HIV-1 RNA < or = 400 copies/ml than the SBG group (46% versus 13%, P = 0.002). Non-response to ABC was associated with multiple baseline zidovudine (ZDV)/stavudine (d4T)-associated mutations. Baseline RT mutation patterns differed in 14 out of 21 (67%) paired samples from plasma and CSF. Four subjects experienced > 1 log10 copies/ml reductions in CSF HIV-1 RNA, two in the absence of reductions in plasma HIV-1 RNA and two with undetectable plasma HIV-1 RNA at baseline. CONCLUSIONS: Substantial decreases in plasma and CSF HIV-1 RNA following addition of ABC were not precluded by baseline HIV-1 NRTI-associated mutations, including the M184V mutation, but non-responders commonly harbored multiple ZDV/d4T-associated mutations. HIV-1 RNA responses and RT genotype appear to be discordant between CSF and plasma in some subjects.

Kaposi's sarcoma and central nervous system disease: a real association or an artifact of the control group? Terry Beirn Community Programs for Clinical Research on AIDS.

OBJECTIVES: To test the hypothesis that Kaposi's sarcoma (KS) protects against four central nervous system (CNS) diseases in HIV-1-infected individuals. STUDY POPULATION AND DESIGN: The study population of 9404 subjects included participants in Terry Beirn Community Programs for Clinical Research on AIDS (CPCRA) protocols who were enrolled between September 1990 and September 1998. This was an observational study. METHODS: Proportional hazards regression was used to estimate adjusted relative risks for predictors of four central nervous system diseases. Covariates included occurrence of Kaposi's sarcoma, occurrence of other opportunistic infections or malignancies, baseline CD4+ count, and other baseline characteristics. RESULTS: Among the 5944 participants without progression to AIDS at entry, 451 developed a CNS disease. The adjusted relative risk of any CNS disease for those who developed Kaposi's sarcoma versus those who did not develop any AIDS-defining event was 1.41 [95% confidence interval (CI), 0.98-2.03; P = 0.06]. In contrast, the adjusted relative risk of any CNS disease for those with Kaposi's sarcoma versus those with some other non-Kaposi's sarcoma AIDS-defining event was 0.37 (95% CI, 0.24-0.57; P < 0.0001). Among the 3460 participants with progression to AIDS at entry, the adjusted relative risk of any CNS disease for those with Kaposi's sarcoma versus those with some other non-Kaposi's sarcoma AIDS-defining event was 0.71 (95% CI, 0.40-1.25; P = 0.23). CONCLUSIONS: Our analyses indicate that the risk of CNS disease associated with Kaposi's sarcoma depends strongly on the reference or control group chosen. When compared to individuals with other non-Kaposi's sarcoma AIDS-defining diseases, Kaposi's sarcoma is associated with a lower risk of CNS disease in HIV-1 positive individuals. However, when compared to individuals with no AIDS-defining disease or with a similarly mild AIDS-defining disease such as invasive candidiasis, Kaposi's sarcoma is associated with an equivalent risk of CNS disease.

Neurological outcomes in late HIV infection: adverse impact of neurological impairment on survival and protective effect of antiviral therapy. AIDS Clinical Trial Group and Neurological AIDS Research Consortium study team.

OBJECTIVE: In a large multi-center clinical trial of combination reverse transcriptase inhibitors (RTIs), we assessed the impact of antiretroviral therapy on neurological function, the relationship between neurological and systemic benefit, and the prognostic value of neurological performance in late HIV-1 infection. DESIGN: Neurological evaluations incorporated in a randomized, multi-center trial of combination antiretroviral therapy. SETTING: Forty-two AIDS Clinical Trials Group sites and seven National Hemophilia Foundation sites. PATIENTS: Adult HIV-infected patients (n = 1313) with CD4 counts < 50 x 10(6) cells/l. INTERVENTIONS: Four combinations of reverse transcriptase inhibitors consisting of zidovudine (ZDV), alternating monthly with didanosine (ddl), or in combination with zalcitabine (ddC), ddl or ddl and nevirapine. MAIN OUTCOME MEASURES: Mean change from baseline of a four-item quantitative neurological performance battery score, the QNPZ-4, administered to 1031 subjects. RESULTS: Triple therapy and ZDV/ddl combination preserved or improved neurological performance over time compared with the alternating ZDV/ddl and ZDV/ddC regimens (P < 0.001), paralleling their impact on survival in the same trial as previously reported. QNPZ-4 scores were predictive of survival (P < 0.001), after adjusting for CD4 counts and HIV-1 plasma RNA concentrations. CONCLUSIONS: Combination antiretroviral therapy can have a salutary effect on preserving or improving neurological function. Superior systemic treatments may likewise better preserve neurological function. The significant association of poor neurological performance with mortality, independent of CD4 counts and HIV-1 RNA levels indicates that neurological dysfunction is an important cause or a strong marker of poor prognosis in late HIV-1 infection. This study demonstrates the value of adjunctive neurological measures in large therapeutic trials of late HIV-1 infection.

Time course of cerebrospinal fluid responses to antiretroviral therapy: evidence for variable compartmentalization of infection.

OBJECTIVES: To compare the kinetics and magnitude of HIV-1 RNA responses to antiretroviral therapy (ART) in the cerebrospinal fluid (CSF) and plasma. DESIGN: Repeated lumbar punctures (LPs) were performed after the initiation or change in ART in 15 HIV-1-infected subjects, with the focus on two phases of response: an acute phase within the first 11 days, for which crude estimates of viral RNA half-lives and decay rates were derived and CSF:plasma relative decay ratios quantitatively analysed; and a longer-term phase beyond 4 weeks that was descriptively assessed. RESULTS: In 13 subjects studied during the acute phase, the crude HIV-1 RNA half-life was longer (median 2.0 compared with 1.9 days), the decay rate slower (median 0.13 compared with 0.16 log10 copies/day) and, most notably, the variability greater (intraquartile range of half-life 1.8-4.3 compared with 1.7-2.1 days) in the CSF than in the plasma. A slower decay in the CSF correlated with lower initial blood CD4 T lymphocyte counts (P = 0.001). Seven of 11 subjects studied at 4 weeks or later, including some with slower acute-phase CSF responses, showed greater or more durable viral suppression in the CSF. CONCLUSION: Divergent acute-phase viral kinetics in the CSF and plasma, and proportionally greater long-term decrements in CSF HIV-1 RNA in slow early-responders or poor overall plasma responders indicate variable compartmentalization of CSF infection, consistent with a model of two prototypes of CSF infection: short-lived, transitory infection that predominates in early HIV-1 infection and longer-lived, more autonomous CSF infection predominating in late HIV-1 infection. Additional studies will be needed to define more precisely the acute and longer-term CSF kinetics in different clinical settings and to assess this model.

Failure to detect nelfinavir in the cerebrospinal fluid of HIV-1--infected patients with and without AIDS dementia complex.

OBJECTIVE: To assess the penetration of the HIV-1 protease inhibitor, nelfinavir, into cerebrospinal fluid (CSF). DESIGN: Nelfinavir, a commonly used HIV-1 protease inhibitor (PI), is highly effective for reducing plasma viral load. It is deployed clinically in combination with other antiretroviral agents, including nucleoside and nonnucleoside reverse transcriptase inhibitors (NRTIs and NNRTIs). Despite its potency based on plasma HIV-1 RNA results, its effectiveness in reducing HIV-1 RNA levels (i.e., viral load) in the central nervous system (CNS) is less certain. We sampled the CSF as a surrogate for brain because this fluid also is separated from the blood by a barrier to free diffusion, the blood-CSF barrier (BCB), which shares properties with the blood-brain barrier (BBB). These studies of nelfinavir CSF pharmacokinetics exploited the multiple CSF samples derived from individual study subjects who were enrolled in studies the primary objective of which was to compare viral kinetics in CSF and blood in response to antiviral therapy. METHODS: Six study subjects, four with and two without AIDS dementia complex, underwent multiple lumbar punctures (LP). Intervals of CSF sampling after drug dosing were varied (from 0.48 hours to 10.3 hours after nelfinavir administration) to quantitate nelfinavir concentrations throughout the steady-state dosing interval. In four study subjects, CSF sampling was accompanied by assessment of nelfinavir levels in plasma before and after LP, whereas in the other two subjects, a single plasma sample was obtained before or after the LP. In total, 25 CSF samples were analyzed. Nelfinavir concentrations in CSF and plasma were determined using an high-performance liquid chromatography (HPLC) method with a limit of quantitation of 25 and 50 ng/ml, respectively. RESULTS: Plasma concentrations before and after LP averaged 2420+/-1365 ng/ml and 2528+/-1132 ng/ml, respectively. Nelfinavir was not detected in any of the CSF samples and levels >25 ng/ml were not present in the CSF. Thus, standard therapy with nelfinavir does not result in CSF drug concentrations at or exceeding the IC95 level for most HIV-1 isolates. However, study subjects with high CSF viral loads experienced a marked reduction in the context of the combination-drug regimen including nelfinavir with two subjects showing a comparable CSF response with that in plasma. CONCLUSIONS: Nelfinavir does not appreciably penetrate into the CSF. The clinical importance of this observation is not certain, in that in four study subjects who initiated nelfinavir in combination with other antiretroviral therapy, a comparable degree of viral suppression was obtained in both the CSF and the blood when sampled 4 weeks or later after initiating therapy.

Experience with a cross-study endpoint review committee for AIDS clinical trials. Terry Beirn Community Programs for Clinical Research on AIDS.

OBJECTIVES: To describe the methods and results of a standardized system for clinical endpoint determination for defining and reviewing endpoints in clinical trials for HIV-infected individuals. DESIGN: A system was developed utilizing standard definitions for the 24 diagnoses or clinical events that serve as trial endpoints and together define the combined endpoint 'progression of HIV disease. A common set of case report forms were used for all trials. Thus, an event of Pneumocystis carinii pneumonia (PCP), for example, for a subject co-enrolled in an antiretroviral trial and a PCP prophylaxis trial was only reported once. METHODS: A central committee was established to define clinical events and review endpoints across all studies. Events were classified according to established criteria for confirmed, probable and possible levels of certainty. RESULTS: This report describes the methods used to ascertain and review endpoints, and summarized 2299 clinical events for 8097 subjects enrolled in one or more of nine clinical trials. Data on the diagnostic certainty of events and agreement between site clinicians and the endpoint committee are presented. CONCLUSIONS: Uniform classification of endpoints across AIDS clinical trials can be accomplished by multicenter, multitrial organizations with standardized definitions and review of endpoint documentation. Our experience suggests that nurse coordinators reviewing all submitted endpoints for every trial are warranted and the need for external review by a clinical events committee may depend on the type of trial conducted.

Stable neurological function in subjects treated with 2'3'-dideoxyinosine.

AIDS Dementia Complex (ADC) is a frequent and devastating complication of HIV infection. There is evidence that zidovudine (ZDV) has an effect in alleviating the symptoms of ADC, and may have a role in its prevention. It is therefore important that new antiretroviral therapies be evaluated not only for the risk of neurologic side effects, but also for their relative efficacy to ZDV in the prevention of ADC. The present study reports the effects of 2'3'-dideoxyinosine (DDI, didanosine, Videx) therapy on neuropsychological performance in the context of several large clinical trials targeting advanced systemic HIV-1 infection. Subjects treated with DDI had stable neurologic performance in quantitative tests over a 1 year period and were similar to zidovudine treated subjects.

Neurological complications of HIV infection.

Neurological complications of HIV infection cause considerable morbidity and are often associated with high mortality. These complications include not only the more common opportunistic diseases affecting the brain (cerebral toxoplasmosis, primary central nervous system lymphoma, progressive multifocal leucoencephalopathy, and cryptococcal meningitis) but also the AIDS dementia complex, with its characteristic cognitive and motor dysfunction, which is caused by HIV itself. Additionally, the peripheral nervous system is the target of several disorders, including a common painful neuropathy. Because these and other, less common, central and peripheral nervous system complications of HIV can often be specifically treated or effectively palliated, their accurate and timely diagnosis is important.