Cerebrospinal fluid neopterin as a biomarker of neuroinflammatory diseases.

The elevation of neopterin in cerebrospinal fluid (CSF) has been reported in several neuroinflammatory disorders. However, it is not expected that neopterin alone can discriminate among different neuroinflammatory etiologies. We conducted an observational retrospective and case-control study to analyze the CSF biomarkers neopterin, total proteins, and leukocytes in a large cohort of pediatric patients with neuroinflammatory disorders. CSF samples from 277 subjects were included and classified into four groups: Viral meningoencephalitis, bacterial meningitis, acquired immune-mediated disorders, and patients with no-immune diseases (control group). CSF neopterin was analyzed with high-performance liquid chromatography. Microbiological diagnosis included bacterial CSF cultures and several specific real-time polymerase chain reactions. Molecular testing for multiple respiratory pathogens was also included. Antibodies against neuronal and glial proteins were tested. Canonical discriminant analysis of the three biomarkers was conducted to establish the best discriminant functions for the classification of the different clinical groups. Model validation was done by biomarker analyses in a new cohort of 95 pediatric patients. CSF neopterin displayed the highest values in the viral and bacterial infection groups. By applying canonical discriminant analysis, it was possible to classify the patients into the different groups. Validation analyses displayed good results for neuropediatric patients with no-immune diseases and for viral meningitis patients, followed by the other groups. This study provides initial evidence of a more efficient approach to promote the timely classification of patients with viral and bacterial infections and acquired autoimmune disorders. Through canonical equations, we have validated a new tool that aids in the early and differential diagnosis of these neuroinflammatory conditions.

Temporal/compartmental changes in viral RNA and neuronal injury in a primate model of NeuroAIDS.

Despite the advent of highly active anti-retroviral therapy HIV-associated neurocognitive disorders (HAND) continue to be a significant problem. Furthermore, the precise pathogenesis of this neurodegeneration is still unclear. The objective of this study was to examine the relationship between infection by the simian immunodeficiency virus (SIV) and neuronal injury in the rhesus macaque using in vivo and postmortem sampling techniques. The effect of SIV infection in 23 adult rhesus macaques was investigated using an accelerated NeuroAIDS model. Disease progression was modulated either with combination anti-retroviral therapy (cART, 4 animals) or minocycline (7 animals). Twelve animals remained untreated. Viral loads were monitored in the blood and cerebral spinal fluid, as were levels of activated monocytes in the blood. Neuronal injury was monitored in vivo using magnetic resonance spectroscopy. Viral RNA was quantified in brain tissue of each animal postmortem using reverse transcription polymerase chain reaction (RT-PCR), and neuronal injury was assessed by immunohistochemistry. Without treatment, viral RNA in plasma, cerebral spinal fluid, and brain tissue appears to reach a plateau. Neuronal injury was highly correlated both to plasma viral levels and a subset of infected/activated monocytes (CD14+CD16+), which are known to traffic the virus into the brain. Treatment with either cART or minocycline decreased brain viral levels and partially reversed alterations in in vivo and immunohistochemical markers for neuronal injury. These findings suggest there is significant turnover of replicating virus within the brain and the severity of neuronal injury is directly related to the brain viral load.

Blood-brain barrier and neuro-AIDS.

Neuro-AIDS is becoming a major health problem among AIDS patients who experience improved survival under combined antiretroviral therapy (cART). Neuronal injury and loss are the critical issues of neuro-AIDS that need the entry of HIV into the central nervous system (CNS) via peripheral infected monocyte/macrophage carriers or viral direct penetration of blood-brain barrier (BBB). The mechanisms of HIV enhancing BBB permeability and entering CNS and the effect of drug abuse in HIV traffic across BBB are discussed. In addition, the current anti-HIV drugs, although they are effective in reducing plasma viral level, cannot eradicate the viruses completely from CNS. The possible mechanism of BBB hindrance and anti-HIV drug efflux by transport proteins, and general methods used to deliver antiretroviral drugs into brain are also discussed.

Impact of minocycline on cerebrospinal fluid markers of oxidative stress, neuronal injury, and inflammation in HIV-seropositive individuals with cognitive impairment.

Elevated cerebrospinal fluid (CSF) levels of markers of oxidative stress, neuronal injury, and inflammation and decreased neurotransmitter levels have been reported in HIV-associated neurocognitive disorders (HAND). Minocycline may have a neuroprotective effect by inhibiting inducible nitric oxide synthase, which produces nitric oxide, a compound that induces oxygen free radical production. In A5235, "Phase II, Randomized, Placebo-Controlled, Double-Blind Study of Minocycline in the Treatment of HIV-Associated Cognitive Impairment," minocycline was not associated with cognitive improvement, but the effect on the above CSF measures was not examined previously. The objective of this study was to examine the effect of minocycline on markers of oxidative stress, neuronal injury, neurotransmitter levels, and inflammation from CSF in participants in A5235. One hundred seven HIV+ individuals received either minocycline 100 mg or placebo orally every 12 h for 24 weeks. Twenty-one HIV+ individuals received the optional lumbar punctures. Lipid and protein markers of oxidative stress (e.g., ceramides and protein carbonyls), glutamate, neurotransmitter precursors, kynurenine metabolites, neurofilament heavy chain, and inflammatory cytokines were measured in the CSF before and after treatment. The 24-week change in ceramides was larger in a beneficial direction in the minocycline group compared to the placebo group. The two groups did not differ in the 24-week changes for other markers.These results suggest that minocycline may decrease lipid markers of oxidative stress (ceramides) in individuals with HAND; however, an effect of minocycline on other CSF markers was not observed. A larger sample size is needed to further validate these results.

Higher HIV-1 genetic diversity is associated with AIDS and neuropsychological impairment.

Standard methods used to estimate HIV-1 population diversity are often resource intensive (e.g., single genome amplification, clonal amplification and pyrosequencing) and not well suited for large study cohorts. Additional approaches are needed to address the relationships between intraindividual HIV-1 genetic diversity and 2 disease. With a small cohort of individuals, we validated three methods for measuring diversity: Shannon entropy and average pairwise distance (APD) using single genome sequences, and counts of mixed bases (i.e. ambiguous nucleotides) from population based sequences. In a large cohort, we then used the mixed base approach to determine associations between measure HIV-1 diversity and HIV associated disease. Normalized counts of mixed bases correlated with Shannon Entropy at both the nucleotide (rho=0.72, p=0.002) and amino acid level (rho=0.59, p=0.015), and APD (rho=0.75, p=0.001). Among participants who underwent neuropsychological and clinical assessments (n=187), increased HIV-1 population diversity was associated with both a diagnosis of AIDS and neuropsychological impairment.

Dual R3R5 tropism characterizes cerebrospinal fluid HIV-1 isolates from individuals with high cerebrospinal fluid viral load.

OBJECTIVE: To study the use of major and alternative coreceptors by HIV-1 isolates obtained from paired plasma and cerebrospinal fluid (CSF) samples. DESIGN: Paired plasma and CSF isolates from HIV-1-infected individuals with varying clinical, virologic, and immunologic parameters were assessed for the ability to infect indicator cells expressing a panel of coreceptors with documented expression in the central nervous system (CNS). METHODS: HIV-1 isolates obtained from plasma and CSF in 28 individuals with varying viral load, CD4 T-cell counts, and with or without AIDS-defining disease were analyzed for the ability to infect NP2.CD4 cells stably expressing a panel of HIV coreceptors (CCR5, CXCR4, CCR3, CXCR6, GPR1, APJ, ChemR23, RDC-1 or BLT1). RESULTS: All isolates from both plasma and CSF utilized CCR5 and/or CXCR4. However, the ability to use both CCR3 and CCR5 (R3R5) was more pronounced in CSF isolates and correlated with high CSF viral load and low CD4 T-cell count. Notably, four out of five CSF isolates of subtype C origin exhibited CXCR6 use, which coincided with high CSF viral load despite preserved CD4 T-cell counts. The use of other alternative coreceptors was less pronounced. CONCLUSION: Dual-tropic R3R5 HIV-1 isolates in CSF coincide with high CSF viral load and low CD4 T-cell counts. Frequent CXCR6 use by CSF-derived subtype C isolates indicates that subtype-specific differences in coreceptor use may exist that will not be acknowledged when assessing plasma virus isolates. The findings may also bare relevance for HIV-1 replication within the CNS, and consequently, for the neuropathogenesis of AIDS.

White matter tract injury and cognitive impairment in human immunodeficiency virus-infected individuals.

Approximately half of those infected with the human immunodeficiency virus (HIV) exhibit cognitive impairment, which has been related to cerebral white matter damage. Despite the effectiveness of antiretroviral treatment, cognitive impairment remains common even in individuals with undetectable viral loads. One explanation for this may be subtherapeutic concentrations of some antiretrovirals in the central nervous system (CNS). We utilized diffusion tensor imaging and a comprehensive neuropsychological evaluation to investigate the relationship of white matter integrity to cognitive impairment and antiretroviral treatment variables. Participants included 39 HIV-infected individuals (49% with acquired immunodeficiency syndrome [AIDS]; mean CD4 = 529) and 25 seronegative subjects. Diffusion tensor imaging indices were mapped onto a common whole-brain white matter tract skeleton, allowing between-subject voxelwise comparisons. The total HIV-infected group exhibited abnormal white matter in the internal capsule, inferior longitudinal fasciculus, and optic radiation; whereas those with AIDS exhibited more widespread damage, including in the internal capsule and the corpus callosum. Cognitive impairment in the HIV-infected group was related to white matter injury in the internal capsule, corpus callosum, and superior longitudinal fasciculus. White matter injury was not found to be associated with HIV viral load or estimated CNS penetration of antiretrovirals. Diffusion tensor imaging was useful in identifying changes in white matter tracts associated with more advanced HIV infection. Relationships between diffusion alterations in specific white matter tracts and cognitive impairment support the potential utility of diffusion tensor imaging in examining the anatomical underpinnings of HIV-related cognitive impairment. The study also confirms that CNS injury is evident in persons infected with HIV despite effective antiretroviral treatment.

Acute paraplegia in a patient with AIDS and a normal CSF examination.

We report a case of tuberculous myeloradiculitis in a patient with AIDS. The case highlights the difficulty in reaching a diagnosis for the neurological symptoms of a patient with a normal CSF examination and the need for HIV screening of immune-compromised patients with myeloradiculitis.

Atypical forms of Cryptococcus neoformans in CSF of an AIDS patient.

The microscopic recognition of typical rounded capsulated yeasts in centrifuged cerebrospinal fluid (CSF), stained with India ink, is a common, rapid and effective method for the diagnosis of cryptococcal meningitis among AIDS patients. The presence of atypical forms of Cryptococcus neoformans var. neoformans in samples of CSF of an AIDS patient with cryptococcosis treated at the University Hospital of Infectious Disease is presented. The India ink microscopy of three consecutive CSF samples revealed capsulated yeast with India ink particles in the deteriorated capsules and capsulated pseudohyophae. Clinically, the patient showed a subacute meningoencephalitis, with a clinical picture not particularly different from those commonly observed in patients with AIDS-associated cryptococcosis treated in our hospital. In all cases, the culture of the CSF showed colonies of C. neoformans with typical macro and micromorphology, and the in vitro susceptibility tests to amphotericin B, fluocitosine, itraconazole and fluconazole showed MIC values into the limits of sensitivity. The presence of atypical forms of C. neoformans, considered as an atypical finding, could be the consequence of an adaptive phenomenon of this fungal species to an impaired immunological status present in the host.

Meeting practical challenges of a trial involving a multitude of treatment regimens: an example of a multi-center randomized controlled clinical trial in neuroAIDS.

Many clinical trials compare one specific treatment to a control or standard treatment. In HIV therapeutics, such fixed-regimen designs may be problematic as individualized treatment regimens are standard practice. Designing and implementing a trial that allows individualized treatment options poses particular challenges. In this example of a clinical trial in NeuroAIDS, it is hypothesized that some antiretroviral drugs [i.e., those that penetrate the blood-brain barrier sufficiently to inhibit HIV in the central nervous system (CNS)] will improve HIV neurocognitive impairment, whereas non-penetrating antiretrovirals will not be as effective in improving neurocognitive function. To test this hypothesis, a uniquely designed strategy trial was developed that consists of three essential components: (1) a scoring system that ranks regimens for CNS penetration based on semiquantitative criteria, (2) committee-established individualized regimen options that allow randomization to opposite ends of the CNS penetration spectrum, and (3) timely implementation across multiple centers via web-based resources. For the proposed trial, the three components are combined with an adaptive randomization scheme to minimize potential confounding by several important factors. A small pilot study demonstrated the feasibility and acceptability to providers. In conclusion, an innovative design can provide solutions to challenging practical issues in trials with multiple treatment options.

The role of cohort studies in drug development: clinical evidence of antiviral activity of serotonin reuptake inhibitors and HMG-CoA reductase inhibitors in the central nervous system.

BACKGROUND: Effective antiretroviral therapy (ART) has reduced the incidence of HIV-associated neurocognitive impairment (HNCI) but its prevalence remains high. Clinical trials have yet to identify a consistently effective treatment for HNCI, other than ART, but in vitro data support that some drugs approved by the Food and Drug Administration (FDA) for other indications might benefit individuals with HNCI. Some of these drugs, such as serotonin reuptake inhibitors (SRIs) and HMG-CoA reductase inhibitors (statins), may do so by reducing HIV replication in the CNS and are already widely used by HIV-infected individuals. METHODS: Six-hundred fifty-eight HIV-infected participants of the CHARTER cohort had a baseline assessment, which included comprehensive neuropsychological (NP) testing and HIV RNA measurements in plasma and cerebrospinal fluid (CSF). Four-hundred sixty-seven (71%) subjects used ART, 195 (30%) used SRIs, and 63 (10%) used statins. RESULTS: SRI users were less likely to have HIV RNA levels in CSF above 50 copies (c)/mL (29 vs. 37% in non-SRI users, OR 0.69, p = 0.05). This association was most evident for three of the seven SRIs (citalopram, sertraline, and trazodone, or "antiviral" SRIs, combined 25 vs. 38% in non-SRI users, OR 0.56, p = 0.01) and was strongest in those not taking concomitant ART (61 vs. 83%, OR 0.31, p = 0.01). "Antiviral" SRI users also performed better on NP tests (median global deficit score 0.37 vs. 0.47, p = 0.04). Statin users were also less likely to have HIV RNA levels in CSF above 50 c/mL (16 vs. 37%, p < 0.001) but, in contrast to SRIs, the association was strongest in those taking ART (2 vs. 18%, p < 0.001). Statin use was not associated with better NP performance. Multivariate analyses indicated that the use of "antiviral" SRIs-but not statins-was associated with undetectable HIV RNA levels in CSF and better NP performance. CONCLUSIONS: SRIs may reduce HIV replication in CSF and improve NP performance. This was particularly true for three SRIs-supporting differences in antiviral efficacy between drugs-in individuals who were not taking ART. In contrast, statins were not associated with lower HIV replication in CSF in multivariate analyses and were not associated with better NP performance. These analyses support the value of large observational cohort studies in identifying FDA-approved drugs that may be worth further investigation.

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.

Leptomeningeal lymphoma in a child with acquired immune deficiency syndrome.

Primary non-Hodgkin lymphoma of the central nervous system is rare in pediatric AIDS patients. We report a seven-year-old HIV-infected boy, in stage C3 of the disease, who developed non-Hodgkin lymphoma in the central nervous system with a leptomeningeal location. The patient started with signs and symptoms of increased intracranial pressure, impaired consciousness and then became blind. The diagnosis was based on brain biopsy, immunophenotypic studies of B cells, and Epstein-Barr virus serology of the cerebrospinal fluid. The boy was treated with intrathecal and systemic chemotherapy. Fifteen months after diagnosis he had clinically improved, but he then relapsed with a thalamic tumor. He was treated with radiotherapy and he died four months later. In the present article, we discuss diagnostic difficulties, evolution, treatment, and the association of this neoplasm with the Epstein-Barr virus.

Simian virus 40 sequences in an AIDS patient with a cerebral lesion: a case report.

Simian virus 40 (SV40) DNA sequences were found, by PCR analysis followed by filter hybridization, in the cerebrospinal fluid of a 29-y-old male affected by AIDS with an undefined cerebral lesion. This case illustrates the need to consider the SV40 polyomavirus among viral agents potentially responsible of encephalitis and neurological disorders in AIDS patients.

JC virus DNA in cerebrospinal fluid samples from Brazilian AIDS patients with focal brain lesions without mass effect.

OBJECTIVE: To evaluate the presence of JC virus DNA in CSF samples from Brazilian AIDS patients with focal lesions of CNS white matter without mass effect compatible with progressive multifocal leukoencephalopathy (PML). METHODS: CSF samples from AIDS patients with neurological symptoms and a CT scan showing focal lesions of CNS white matter without mass effect suggestive of PML, and from AIDS and non-AIDS patients with non-PML neurological diseases were tested for JC virus DNA by PCR. The primers used to amplify the T antigen region of the JC virus resulted in a 173-bp fragment. The presence of the JC virus was confirmed by digestion of the PCR product using BamH1. RESULTS: The PCR for JCV DNA was negative in 119/120 non-PML CSF samples (specificity =99.2%). Of 56 CSF samples from AIDS patients with focal lesions of CNS white matter without mass effect, JCV DNA was positive in 48.2% (27/56). In 23/29 (79.3%) JCV DNA-negative cases, other causes for the encephalitic lesions were found. No JCV DNA-positive cases showed other diagnoses. CONCLUSIONS: The prevalence of JCV DNA by PCR in CSF samples from Brazilian AIDS patients with focal brain lesions, without mass effect was 48.2%. In these patients, a negative JCV PCR is highly suggestive of other neurological conditions.

The blood brain barrier in HIV infection.

The blood brain barrier (BBB) serves as a protective mechanism for the brain. It prevents entry of pernicious substances, whether chemical or cellular, from free access to the CNS. In essence, it is a defense mechanism preserving the internal milieu of the brain. The BBB may be disrupted by a number of pathological processes. CNS infection is a well recognized cause of BBB disruption. Among the CNS infections demonstrated to affect the BBB is human immunodeficiency virus (HIV). HIV infects the brain shortly after its acquisition. Studies of cerebrospinal fluid (CSF) as well as dynamic studies of contrast enhanced magnetic resonance imaging have confirmed abnormalities of the BBB in HIV-infected persons. Pathological studies of the CNS have confirmed the in vivo studies, and in vitro studies have identified a range of pathogenic mechanisms of HIV-associated BBB compromise. This disruption of the BBB may not only contribute to accelerating brain infection by HIV, but may also alter CNS function. Additionally, BBB disruption has implications with respect to antiretroviral therapy. This review will address these issues.

Progressive multifocal leukoencephalopathy in an adult patient with ICF syndrome.

We report on a patient affected by ICF syndrome (immunodeficiency, centromeric instability of chromosomes 1, 9 and 16 and facial dysmorphism), who presented with slowing in mentation, mild right hemiparesis and focal motor seizures. MRI study of the brain suggested a diagnosis of progressive multifocal leukoencephalopathy (PML), which was confirmed by JC virus DNA detection on CSF by polymerase chain reaction (PCR). This is a unique case of adult infective neurological complication described in ICF Syndrome.

Serum and cerebrospinal fluid levels of interleukin-18 in human immunodeficiency virus type 1-associated central nervous system disease.

Interleukin-18 (IL-18) is a proinflammatory cytokine released by macrophages that strongly stimulates the production of interferon-gamma, thereby linking innate and acquired immunity. Its role in human immunodeficiency virus (HIV) pathogenesis is under debate and little is known about its role in neuro-AIDS (acquired immunodeficiency syndrome). Serum and cerebrospinal fluid (CSF) levels of IL-18 were determined by a commercially available enzyme-linked immunosorbent assay (ELISA) in 22 HIV-seropositive patients without neurological symptoms (HIV+), 21 patients with AIDS dementia complex (ADC), and 31 patients with AIDS-defining opportunistic infections (OIs) of the brain. Thirty-two HIV seronegative patients (HIV-) served as controls. Compared to HIV- controls, serum IL-18 levels were increased in HIV+ and ADC but not in OI patients. In contrast, CSF IL-18 levels were elevated in OI patients whereas HIV+ and ADC patients were not different from HIV- controls. We provide evidence for an significantly increased IL-18 level in the CSF of HIV+ patients with cerebral OIs, suggestive of a role for IL-18 in the intrathecal host response to OIs.