Neurological complications of acquired immune deficiency syndrome: analysis of 50 patients

Chemokines: integrators of pain and inflammation

Chronic (neuropathic) pain is one of the most widespread and intractable of human complaints, as well as being one of the most difficult syndromes to treat successfully with drugs or surgery. The development of new therapeutic approaches to the treatment of painful neuropathies requires a better understanding of the mechanisms that underlie the development of these chronic pain syndromes. It is clear that inflammatory responses often accompany the development of neuropathic pain, and here we discuss the idea that chemokines might be key to integrating the development of pain and inflammation and could furnish new leads in the search for effective analgesic agents for the treatment of painful neuropathies.

Activation of c-Jun N-terminal kinase mediates gp120IIIB- and nucleoside analogue-induced sensory neuron toxicity

Peripheral neuropathy is the most common neurological symptom in patients with acquired immunodeficiency syndrome (AIDS). Here, we examine possible mechanisms of gp120 and nucleoside reverse transcriptase inhibitors (NRTIs) in the pathogenesis of AIDS peripheral neuropathy. Neonatal dorsal root ganglion (DRG) neurons were found to undergo apoptosis in response to chronic treatment with gp120IIIB, an effect enhanced by the co-application of hCD4, as well as upon exposure to the nucleoside reverse transcriptase inhibitor (NRTI), 2',3'-dideoxyinosine (ddI). DRG neurons were rescued from the neurotoxic effects of these agents by CEP-1347, an inhibitor of the mixed lineage kinases (MLKs), upstream activators of the c-Jun N-terminal kinase (JNK) signaling pathway. In addition, gp120- or ddI-mediated toxicity were also inhibited by neuronal expression of dominant negative versions of the MLKs. Our results suggest that both gp120 and the NRTIs cause sensory neuron apoptosis through the activation of the JNK pathway, and that CEP-1347-like compounds may serve as a therapeutic option in patients with AIDS-associated peripheral neuropathy.

The frequency of peripheral neuropathy in a group of HIV positive patients in Brazil

Peripheral neuropathy is a common neurological complication occurring in asymptomatic and symptomatic stages of HIV infection. The most common syndromes are distal symmetric polyneuropathy, inflammatory demielinating polyneuropathy, poliradiculopathy, mononeuropathy, mononeuropathy multiplex and autonomic neuropathy. PURPOSE: To evaluate the frequency of peripheral neuropathy in a group of HIV seropositive outpatients in São Paulo, Brazil. METHOD: Over a period of 17 months, 49 HIV+ patients where evaluated clinically. Laboratory analysis and electroneuromyography were requested to all patients. RESULTS: >Thirty four (69.4%) of the 49 patients had the diagnosis of peripheral neuropathy established on clinical grounds. The most common sign was impairment (97.1%) of sensibility. Thirteen (33.3%) of the 39 that were subjected to electroneuromyography had features of peripheral neuropathy, being a sensitive-motor axonal neuropathy the most common. No abnormalities were found in the laboratory analysis performed in 42 patients, except in four who had VDRL positive. CONCLUSION: A peripheral neuropathy was frequently found upon clinical examination in our group of HIV positive individuals.

Galloping Ophthalmoplegia and Numb Chin in Burkitt Lymphoma

A 57-year-old man developed complete bilateral ophthalmoplegia over a period of 10 days, together with bilateral facial pain and numbness of the chin. He had no other clinical manifestations. Findings on brain magnetic resonance imaging and spinal fluid formula from the first lumbar puncture were normal, but cerebrospinal fluid flow cytometry disclosed a kappa restriction monoclonal B-cell population, indicating malignant lymphoma. Computed tomography of the chest, abdomen, and pelvis then revealed multiple enlarged lymph nodes. Biopsy of an inguinal node showed findings consistent with Burkitt lymphoma. Within six weeks, intravenous and intrathecal chemotherapy resolved all neurologic findings except a partial right-side sixth nerve palsy and mild chin numbness. Eighteen months after disease onset, the patient remained in remission. Meningeal spread of Burkitt lymphoma is not commonly a presenting feature in immunocompetent adults. Chin numbness, a characteristic feature caused by infiltration of the mental nerve, should facilitate earlier recognition, which may be life saving.

HIV Dementia

Dementia and milder forms of cognitive impairment are important manifestations, with important socioeconomic consequences, of HIV infection. Early detection and aggressive treatment are essential to achieve stabilization and prevent progression. In some affected individuals, reversal of symptoms may follow initiation of effective therapy. Antiretroviral treatment needs to be individualized, taking into consideration the relative central nervous system penetration of the drugs, presence of drug resistant viral strains, possible drug interactions, and drug side effect profiles. Combination antiretroviral therapy is preferred. Zidovudine, stavudine, abacavir, navirapine and indinavir have relatively good penetration into the central nervous system. The aim of therapy should be for control of viral load in the periphery and the cerebrospinal fluid. Furthermore, although not established therapy, the use of neuroprotective agents and anti-inflammatory regimens may be considered. A comprehensive multidisciplinary approach to management with regular follow-up is essential for treatment.

Risk modifiers for peripheral sensory neuropathy in HIV infection/AIDS

The objective of this study is to examine the risk factors associated with the development of sensory neuropathy in human immunodeficiency virus (HIV)-infected patients in 292 HIV+ patients recruited through a community-based sentinel survey. We determined the clinical and treatment factors associated with the presence of peripheral sensory neuropathy in HIV+ subjects at baseline examination, and at 1-year follow-up. Baseline examination was assessed with a logistic regression analysis controlling for age, education level, history of drug/alcohol use, and anti-retroviral treatment. The risk of developing new peripheral neuropathy at follow-up was determined using a Cox proportional hazard model analysis. At study entry, neuropathy (n=64) was associated with acquired immunodeficiency syndrome (AIDS), nucleoside analogue reverse transcriptase inhibitors (NRTI) (i.e. ddC), and history of alcohol abuse. After 1-year follow-up, the development of neuropathy was predicted by AIDS, age (older subjects), and NRTI use. These findings indicated that AIDS, age, alcohol abuse/dependence, and anti-retroviral medication use are important predictors of motor/sensory peripheral neuropathy in the HIV infection. The peripheral neurotoxic effect of anti-retroviral medication should be taken into account in the design of long-term therapies.

Anticonvulsant and antiretroviral interactions

OBJECTIVE

To evaluate the clinical significance of interactions between anticonvulsant and antiretroviral agents and provide recommendations regarding their concurrent use.

DATA SOURCES

A PubMed search (1966 to April 2003) was conducted using individual anticonvulsant and antiretroviral drug names and the following key search terms: anticonvulsant, antiepileptic, antiretroviral, protease inhibitor, and pharmacokinetic. Abstracts from scientific meetings that pertained to drug interactions were manually reviewed.

STUDY SELECTION AND DATA EXTRACTION

All articles identified by the PubMed search were examined. Articles and abstracts from scientific meetings with relevant information were included.

DATA SYNTHESIS

Six case reports were identified that describe interactions between anticonvulsant agents and protease inhibitors. In several reports, carbamazepine serum concentrations increased by approximately two- to threefold with concurrent ritonavir, resulting in carbamazepine-related toxicity. Carbamazepine was also associated with loss of viral suppression when combined with indinavir. Phenytoin serum concentrations were decreased with nelfinavir in a patient who developed recurrent seizures. The effect of ritonavir on phenytoin was variable; a 30% reduction in phenytoin serum concentration occurred in one patient, while no apparent change was observed in another. Interactions with nonnucleoside reverse-transcriptase inhibitors are poorly characterized because existing data involve concurrent protease inhibitor therapy. The utility of newer anticonvulsant agents is explored. Experience with newer anticonvulsant agents in 2 patients at our site is also described.

CONCLUSIONS

Limited data exist regarding interactions between anticonvulsant and antiretroviral agents. Valproic acid and newer anticonvulsant agents may provide useful alternatives to first-generation agents. Clinicians need to be diligent when monitoring for anticonvulsant-antiretroviral interactions because of the potential for toxicity, loss of seizure control, and incomplete viral suppression.

Assessing negative thoughts in response to pain among people with HIV

A growing body of literature suggests that negative thoughts and interpretations in response to pain can significantly increase the suffering associated with the pain experience. As part of an outcome study on a cognitive-behavioral treatment for HIV-related peripheral neuropathic pain, 85 seropositive men and women were administered the inventory of negative thoughts in response to pain (INTRP), a self-report assessment that includes three subscales: negative self-statements, negative social cognitions and self-blame. Pearson product moment correlations coefficients were calculated between INTRP scores and pain and distress ratings. A series of regression analyses were performed to determine predictors of pain and distress. Results demonstrated highly significant associations between the negative self-statements and negative social cognitions and pain intensity. Highly significant associations were also found between negative self-statements, negative social cognitions, self-blame and measures of pain interference, affective symptoms and distress. Additionally, negative cognitions significantly predicted interference in daily functional activities, overall distress and affective symptoms. Future directions for developing and testing cognitive-behavioral treatments for restructuring dysfunctional cognitions are indicated. Finally, internal scale reliability of the INTRP was shown to be moderately high and this study offers construct validity of the INTRP as a useful tool for assessing thoughts in response to pain in people with HIV.

JC virus-induced changes in cellular gene expression in primary human astrocytes

Cell-type-specific transcription of the JC virus (JCV) promoter in glial cells initiates a series of events leading to viral replication in the brain and the development of the fatal demyelinating disease progressive multifocal leukoencephalopathy (PML) in patients with neurologic complications due to infection with human immunodeficiency virus type 1. Here we employed an in vitro infection of primary cultures of human astrocytes to compare the transcriptional profile of cellular genes after JCV infection by using an oligonucleotide-based microarray of 12600 genes. Transcription of nearly 355 genes was enhanced and expression of 130 genes was decreased to various degrees. Many transcripts that were increased upon JCV infection were found to encode proteins with properties that suggest their involvement in cell proliferation, including cyclin A and cyclin B1; signaling pathways, such as transforming growth factor beta receptor 1, platelet-derived growth factor receptor and fibroblast growth factor family receptor; and other regulatory events, such as inflammatory responses, including cyclo-oxygenase-2 (Cox-2). Microarray-based data for several cell cycle-regulatory genes were further examined by using Western blot analysis of in vitro infected astrocytes harvested early and late during the infection. Results demonstrate that protein levels of all upregulated genes were found to increase at some point during the infection time course. In parallel, immunohistochemical assessment of cell cycle proteins, including cyclins A, B1, E, and Cdk2, showed positive staining of astrocytes within PML lesions of brain tissue from patients with neuro-AIDS. Microarray analysis was found to be a useful predictor of gene expression in infected cells; however, it may not directly correlate with protein levels during infection with JCV.

Painful and non-painful neuropathy in HIV-infected patients: an analysis of somatosensory nerve function

Fifteen to 50% of AIDS-patients suffer from distal predominantly sensory neuropathy (DSP), which is commonly associated with painful symptoms. In the present study, we have focused on the function of fine calibre nerve channels, in 36 consecutive HIV-1-infected patients with painful (PPN) (n=20; 54%) and non-painful (PN) (n=16) sensory neuropathy, assessed by clinical, quantitative thermal testing (QTT) (31/36), and peripheral nerve conduction examination (32/36). Control QTT data were obtained from 49 healthy subjects with a corresponding age- and sex distribution. Demographics, antiviral treatment, immunological status, and nerve conduction examination did not differ between patients with and without painful symptoms. Hypoaesthesia to warmth, cold, and heat pain was observed in both neuropathy groups when compared to healthy controls. However, the perception threshold to warmth was more often impaired (p<0.01) and the level of impairment was more pronounced (p<0.001) in patients with painful neuropathy. Furthermore, increased pain sensitivity to cold was found only in patients with painful symptoms (p<0.05). An abnormal outcome of any QTT parameter was found in all patients with pain, but only among 62% of patients without pain, p<0.01, and the cumulative frequency of abnormalities in any of the four thermal percepts (warmth, cold, heat pain, and cold pain) was higher in patients with painful symptoms, p<0.0001. This study demonstrates a more pronounced impairment of C-fibre-mediated innocuous warm perception in patients with painful neuropathy, which in the setting of impaired or absent heat pain perception suggests a more generalised loss of function in somatosensory C-fibre channels.

Nucleoside analogues and neuropathy in the era of HAART

BACKGROUND

Sensory neuropathies occur commonly in the setting of HIV infection. Sensory neuropathy (SN) is clearly associated with HIV itself, and in this context develops in association with increased macrophage activation in the peripheral nervous system. A clinically identical SN may also occur as a consequence of exposure to some HIV treatments. In this setting, impaired mitochondrial function is thought to play a role in the development of neurological dysfunction.

OBJECTIVE

This review explores the evidence for the neurotoxicity of HIV and HIV treatments, the effect of nucleoside reverse transcriptase inhibitors on mitochondria, and the likely associations between these.

CONCLUSIONS

Dideoxynucleotide drugs are commonly associated with SN. The nucleoside reverse transcriptase inhibitors inhibit mitochondrial DNA synthesis and may thus exacerbate existing viral-induced nerve damage.

Stroke in black South African HIV-positive patients: a prospective analysis

BACKGROUND AND PURPOSE

Stroke associated with HIV infection is poorly characterized. In this study we analyze the association in a black African population.

METHODS

The clinical, laboratory, and radiological characteristics of 35 hospital-based black South African, heterosexual, HIV-infected patients who did not abuse intravenous drugs and presented with strokes were prospectively studied. The patients were antiretroviral therapy naive. Patients with other intracranial space-occupying lesions were excluded from the study.

RESULTS

The age range was 20 to 61 years (mean, 32.1 years). There were 21 female and 14 male patients, with a female to male ratio of 1.5:1. Cerebral infarction occurred in 33 patients (94%) and intracerebral hemorrhage in 2 patients (6%). Underlying causes were identified in 30 of the 35 patients (86%) and included coagulopathies, meningitis, cardioembolism, and hypertension. The most common coagulopathy was protein S deficiency. No cause was found in 5 patients (14%).

CONCLUSIONS

The results are similar to data from studies on young black African stroke patients who are HIV negative.

Neurotoxic effects of the human immunodeficiency virus type-1 transcription factor Tat require function of a polyamine sensitive-site on the N-methyl-D-aspartate receptor

Human immunodeficiency virus type-I (HIV-1) infection is often associated with neuronal loss in cortical and subcortical regions that may manifest as motor dysfunction and dementia. The function of the HIV-1 transcription protein Tat and subsequent activation of N-methyl-D-aspartate receptors (NMDAr) have been implicated in this form of neurodegeneration. However, it is unclear if Tat interacts directly with the NMDAr and the role of specific NMDAr subunit composition in mediating effects of Tat is also unclear. The present studies examined the ability of HIV-1 Tat1-72 protein (10 pM-1.0 microM) to displace [3H]MK-801 binding and to attenuate spermidine-induced potentiation of this binding in rat brain homogenate comprised of cerebellum, hippocampus, and cerebral cortex. The role of NMDAr polyamine-site function in the neurotoxic effects of Tat was determined using organotypic hippocampal slice cultures. Binding of [3H]MK-801 in adult rat brain homogenate was not reduced by Tat at concentrations below 1 microM. Tat potently inhibited the potentiation of [3H]MK-801 binding produced by co-exposure of membranes to the NMDAr co-agonist spermidine (IC(50)=3.74 nM). In hippocampal explants, Tat produced neurotoxicity in the CA3 and CA1 pyramidal cell layers, as well as in the dentate gyrus, that was significantly reduced by co-exposure to MK-801 (20 microM) and the NMDAr polyamine-site antagonist arcaine (10 microM). Exposure to the HIV-1 Tat deletion mutant (Tatdelta31-61) did not produce neurotoxicity in hippocampal explants. These data suggest that the neurotoxic effects of HIV-1 Tat are mediated, in part, by direct interactions with a polyamine-sensitive site on the NMDAr that positively modulates the function of this receptor.

Genetic and environmental risk factors for idiopathic inflammatory myopathies

Although the studies discussed are beginning to reveal a number of genetic and possible environmental risk factors for myositis, further investigations are needed to fully understand and classify these syndromes. The difficulties in this process include small numbers of subjects with varying disease phenotypes available for study, polygenic risk factors for which it remains unclear which are primary and which are secondary or linked genes, and the lack of validated environmental exposure assessment tools. New technologies and international collaborative approaches, however, may overcome some of these difficulties and allow us to identify genetic and environmental risk factors, as well as the critical gene-environment interactions in the IIM and its subgroups. Nonetheless, our understanding of these diseases is still in the early stages. Although we have learned a great deal about these disorders through detailed investigations over the last several decades, we have even further to go to understand the environmental triggers and genetic susceptibilities for the myositis syndromes.

AZT myopathy and HIV-1 polymyositis: one disease or two?

PURPOSE

This paper discusses the association between inflammatory and mitochondrial pathologies in patients with HIV-1/AIDS treated with zidovudine (AZT).

METHODS

We present the clinical and pathological details of a 52-year-old HIV-1 positive male who presented with progressive muscle weakness. We also review the current literature and address the debated pathogenesis of the inflammatory pathology.

RESULTS

Muscle biopsy revealed evidence of both HIV-1 polymyositis and AZT myopathy. Six months after initiation of corticosteroid therapy and discontinuation of AZT, the patient's symptoms had greatly improved. The biopsy was repeated to show that both pathologies had resolved.

CONCLUSIONS

The perceived overlap in the pathological spectra of HIV-1 polymyositis and AZT myopathy has produced some debate on causation and treatment. Unfortunately, there have been very few reports where a repeat biopsy following a drug washout period confirmed resolution of the pathology. Furthermore, affected patients have not been treated in a uniform fashion. Whether this represents one disease or two remains uncertain. The clinical relevance of this issue lies in the potential for harm from the unnecessary use of corticosteroids. This question may be best addressed by a randomized clinical trial.

HIV and the central nervous system

Neurological complications of HIV infection are common with clinically recognized disorders ultimately affecting between 40% and 75% of patients. The spectrum of neurological disease is broad. This article highlights the common disorders of the central nervous system associated with HIV/AIDS.

Review: small-fiber neuropathy

BACKGROUND

Most peripheral neuropathies involve large as well as small-fiber dysfunction. A small subset of neuropathies present with restricted or predominant small-fiber involvement.

REVIEW SUMMARY

In this review, we discuss the differential diagnosis, clinical presentation, evaluation, and treatment of small-fiber neuropathies. Although these neuropathies are rare, their differential diagnosis is broad, and includes many disorders, including metabolic, toxic, inflammatory, infectious, and genetic etiologies. As small fibers subserve pain and autonomic functions, these neuropathies usually present with pain and temperature loss, painful dysesthesias, autonomic dysfunction, or a combination. These neuropathies are especially challenging as nerve conductions and EMG, which help guide the evaluation of most peripheral neuropathies, may have normal findings in patients with small-fiber neuropathies. Other specialized studies, including tests of autonomic function, intraepidermal nerve fiber analysis, and quantitative sensory testing, are often required to confirm the presence of a small-fiber neuropathy. In some cases, the underlying etiology can be directly treated. In most, management is limited to symptomatic treatment of sensory and autonomic dysfunction.

CONCLUSION

Small-fiber neuropathies are a heterogeneous group of disorders. They vary in etiologies and require special attention, as many disorders are rare and the differential diagnosis is broad. Evaluation is often extensive and may need pathologic specimen. Many patients respond to symptomatic therapy, but some are difficult to treat.

HTLV-1-mediated immunopathological CNS disease

HAM/TSP is a chronic inflammatory disease of the spinal cord. It is rather rare in HTLV-1-infected individuals. Immunogenetic factors of the HLA complex have been identified that support or prevent the development of the disease. In HAM/TSP patients a characteristic constellation of high proviral loads and increased cellular and humoral immune responses have been established. Immune dysfunction in HAM/TSP patients might be partly explained by HTLV-1 tax p40 transactivation of cellular genes in infected CD4+ T lymphocytes. The oligoclonal expansion of infected T lymphocytes, the variation of tax p40 within HTLV-1 carriers, and the regulation of proviral gene expression are possible determinants for disease development and need to be clarified in future studies.

AIDS dementia

AIDS dementia complex is a relatively recently discovered source of cognitive and motor decline, clearly linked to CNS infection by HIV. While this condition is generally subacutely progressive, and leads to death in a short time-span in untreated patients, improvement in function and prognosis may be achieved by application of highly active antiretroviral therapy. Although this therapy is essential, it may also be necessary in the long term to provide additional neuroprotection, blocking secondary mechanisms of neurotoxicity. With current therapy, infection is never completely eradicated, and significant portions of toxicity seem mediated by indirect mechanisms that may continue even during antiretroviral therapy.

The importance of drug interactions in epilepsy therapy

Long-term antiepileptic drug (AED) therapy is the reality for the majority of patients diagnosed with epilepsy. One AED will usually be sufficient to control seizures effectively, but a significant proportion of patients will need to receive a multiple AED regimen. Furthermore, polytherapy may be necessary for the treatment of concomitant disease. The fact that over-the-counter drugs and nutritional supplements are increasingly being self-administered by patients also must be considered. Therefore the probability of patients with epilepsy experiencing drug interactions is high, particularly with the traditional AEDs, which are highly prone to drug interactions. Physicians prescribing AEDs to patients with epilepsy must, therefore, be aware of the potential for drug interactions and the effects (pharmacokinetic and pharmacodynamic) that can occur both during combination therapy and on drug discontinuation. Although pharmacokinetic interactions are numerous and well described, pharmacodynamic interactions are few and usually concluded by default. Perhaps the most clinically significant pharmacodynamic interaction is that of lamotrigine (LTG) and valproic acid (VPA); these drugs exhibit synergistic efficacy when coadministered in patients with refractory partial and generalised seizures. Hepatic metabolism is often the target for pharmacokinetic drug interactions, and enzyme-inducing drugs such as phenytoin (PHT), phenobarbitone (PB), and carbamazepine (CBZ) will readily enhance the metabolism of other AEDs [e.g., LTG, topiramate (TPM), and tiagabine (TGB)]. The enzyme-inducing AEDs also enhance the metabolism of many other drugs (e.g., oral contraceptives, antidepressants, and warfarin) so that therapeutic efficacy of coadministered drugs is lost unless the dosage is increased. VPA inhibits the metabolism of PB and LTG, resulting in an elevation in the plasma concentrations of the inhibited drugs and consequently an increased risk of toxicity. The inhibition of the metabolism of CBZ by VPA results in an elevation of the metabolite CBZ-epoxide, which also increases the risk of toxicity. Other examples include the inhibition of PHT and CBZ metabolism by cimetidine and CBZ metabolism by erythromycin. In recent years, a more rational approach has been taken with regard to metabolic drug interactions because of our enhanced understanding of the cytochrome P450 system that is responsible for the metabolism of many drugs, including AEDs. The review briefly discusses the mechanisms of drug interactions and then proceeds to highlight some of the more clinically relevant drug interactions between AEDs and between AEDs and non-AEDs. Understanding the fundamental principles that contribute to a drug interaction may help the physician to better anticipate a drug interaction and allow a graded and planned therapeutic response and, therefore, help to enhance the management of patients with epilepsy who may require treatment with polytherapy regimens.

Seizures in HIV-seropositive individuals: epidemiology and treatment

Seizures are a relatively common occurrence in patients with HIV infection. They may be a result of HIV infection of the CNS or a manifestation of an opportunistic infection. Because seizures are likely to recur in patients infected with HIV and because they are a poor prognostic indicator, it is generally recommended that all HIV-seropositive patients experiencing a first seizure without a recognisable and reversible cause be treated. Clinicians faced with treating seizures in HIV-seropositive patients often encounter a therapeutic dilemma since few data exist in this area. In selecting appropriate anticonvulsant therapy, clinicians must consider both therapy-compromising drug-drug and drug-disease interactions. Ideal anticonvulsants for this setting are those that do not effect viral replication, have limited protein binding and have no effects on the cytochrome P450 system, such as gabapentin, topiramate and tiagabine. Unless the benefits outweigh the risks, valproic acid (sodium valproate) should be avoided as it has been shown to stimulate HIV replication. Since few data exist, controlled trials examining pharmacokinetic and pharmacodynamic interactions between anticonvulsants and antiretrovirals are needed. Until such time, clinicians caring for these patients should examine existing data carefully and employ vigilant monitoring.

Lymphomatous meningitis of the Burkitt type presenting with multiple cranial neuropathies

PURPOSE

To describe diplopia as the initial manifestation of the Burkitt lymphoma.

DESIGN

Observational case report.

METHODS

Retrospective chart review.

RESULTS

A 53-year-old human immunodeficiency virus (HIV)-positive man presented with a severe headache associated with binocular diplopia. Flow cytometric analysis of the cerebrospinal fluid demonstrated a monoclonal B-lymphoid cell population consistent with the Burkitt lymphoma.

CONCLUSION

Ophthalmologists should be aware that diplopia may be the presenting manifestation of Burkitt lymphoma in an immunocompromised patient.

Dementia in AIDS patients in Oslo; the role of HIV encephalitis and CMV encephalitis

In a well-defined population of adult AIDS patients from Oslo, we studied the correlation between clinical dementia and autopsy results. The study included 91% of all adult AIDS patients from Oslo who died between 1983 and 1996. The autopsy rate was 73% (167/229). Twenty-three percent of patients had definite dementia and 24% possible dementia. In more than half of the patients with definite dementia multinucleated giant cells were present in the brain tissue, suggesting that the dementia was due to HIV encephalitis. Diffuse damage of white matter also showed a significant association with clinical dementia. When found alone it tended to occur in symptomatic patients with a short survival time from onset of dementia until death. This indicates that diffuse damage of white matter may be an early stage of HIV encephalitis. CMV encephalitis was found in 28 cases (17%). Of these, 20 were classified as definitely or possibly demented. In 14 of these 20 cases we detected no multinucleated giant cells, suggesting that CMV caused or contributed to the dementia. Multiple logistic regression supported an association between CMV and conditions clinically classified as HIV dementia. We conclude that HIV encephalitis is the major cause of dementia in AIDS patients, but that CMV encephalitis as a cause of dementia has been underestimated.

Neurological manifestations of HIV-1 infection in the HAART era

Neurologic complications in patients with AIDS are diverse and include opportunistic infections and lymphoma, as well as HIV-related peripheral neuropathy, myelopathy, and dementia. Improved prophylaxis and antiretroviral therapies have modified the approach to neurologic disease in the setting of AIDS.

Aging and neuro-AIDS conditions and the changing spectrum of HIV-1-associated morbidity and mortality

Older individuals (>50 years of age) now comprise over 11% of patients with AIDS in the United States. This percentage is expected to continue to grow, due both to the improved longevity of patients prescribed highly active antiretroviral therapy (HAART) and to new infections among older individuals. This review focuses on the neuropsychiatric and neurological conditions that are most likely to be affected by advancing age-HIV-1-associated cognitive-motor disorder, peripheral neuropathy, progressive multifocal leukoencephalopathy, primary CNS lymphoma, and risk for cerebrovascular accident. Age associations with incidence of these disorders and with treatment foci are specified. Implications for future changes in management are discussed.

Concomitant progressive multifocal leucoencephalopathy and primary central nervous system lymphoma expressing JC virus oncogenic protein, large T antigen

This report describes the concomitant occurrence of the JC virus (JCV) induced demyelinating disease progressive multifocal leucoencephalopathy (PML) and a primary central nervous system lymphoma (PCNS-L) in a patient with AIDS. Postmortem neuropathological examination revealed characteristic features of PML including multiple lesions of demyelination, enlarged oligodendrocytes with hyperchromatic nuclei (many containing eosinophilic intranuclear inclusions), and enlarged astrocytes with bizarre hyperchromatic nuclei. Immunohistochemical analysis demonstrated the expression of the JCV capsid protein VP-1 in the nuclei of infected oligodendrocytes and astrocytes. The PCNS-L lesion located in the basal ganglia was highly cellular, distributed perivascularly, and consisted of large atypical plasmacytoid lymphocytes. Immunohistochemical examination of this neoplasm identified it to be of B cell origin. Moreover, expression of the JCV oncogenic protein, T antigen, was detected in the nuclei of the neoplastic lymphocytes. This study provides the first evidence for a possible association between JCV and PCNS-L.

[HIV-associated myelopathy: an uncommon indicator of AIDS]

INTRODUCTION

Spinal cord lesions are an uncommon mode of discovering acquired immunodeficiency syndrome because they usually appear at a later stage.

EXEGESIS

We report a 58-year-old patient who had a spastic paraparesia and sphincter dysfunction. The spinal cord magnetic resonance imaging showed spontaneous hypersignals on T2-weighted images at the cervical and thoracic levels, enhanced with gadolinium, and without swelling. No cause was found. The HIV serology was positive and allowed us to consider an HIV-associated myelopathy. The antiretroviral therapy led to functional recovery.

CONCLUSION

An HIV serology is suggested whenever an unexplained intramedullary lesion is discovered. Indeed, the diagnosis of HIV-associated myelopathy implies a specific therapeutic approach.

Detection of HIV-1 gene sequences in hippocampal neurons isolated from postmortem AIDS brains by laser capture microdissection

We employed laser capture microdissection to remove individual pyramidal neurons from the CA1, CA3, and CA4 regions of formalin-fixed, paraffin-embedded hippocampus from 8 AIDS brains and 2 HIV-1-seronegative normal brains. We amplified HIV-1 gag and nef gene sequences using separate, double round PCR reactions for each of the primer sets. In all 3 hippocampal regions, amplification efficiency was best with sequence length between 284 and 324 bp; HIV-1 nef gene sequences were more common than HIV-1 gag sequences; and rank order for percent positive amplification was CA3 > CA4 > CA1 samples. These results are the first to detect HIV-1 gene sequences in microdissected human tissue. They indicate that brain neurons in vivo contain HIV-1 DNA sequences consistent with latent infection by this virus, and suggest that neurons display a selective vulnerability for HIV infection. Neuronal HIV infection could contribute to neuronal injury and death or act as a potential viral reservoir if reactivated.

Disseminated vaccine strain varicella as the acquired immunodeficiency syndrome-defining illness in a previously undiagnosed child

The Food and Drug Administration licensed a live-virus varicella vaccine (Varivax; Merck & Co Inc, West Point, PA) in March 1995. Prelicensure adverse events were minimal; however, since licensure and increased vaccine use, rare previously undetected risks have arisen. Presented here is the clinical course of a previously undiagnosed, human immunodeficiency virus-infected boy who developed dissemination of the vaccine strain of varicella zoster after immunization. chickenpox, human immunodeficiency virus, pneumonia, encephalopathy, varicella vaccine, adverse events, dissemination.

Neuropathology of NFHgp160 transgenic mice expressing HIV-1 env protein in neurons

The physiopathology of HIV-1 dementia remains largely hypothetical. Although several sets of evidence point towards an indirect multicellular inflammatory pathway, gp120, one of the HIV-1 env products, was shown to be very cytotoxic for neurons in vitro. To explore a direct pathway in the physiopathology of dementia in AIDS, we developed transgenic mouse models carrying the HIV-1 env proteins gp 120 and gp 41 (gp 160) under the control of the human light neurofilament and murine heavy neurofilament promoters. To date, this is the first mouse model in which the HIV-1 env protein can be detected in neurons by immunohistochemistry. The expression is found in several brainstem and spinal cord gray structures and in the cerebellum in one of the mouse lines bearing the NFHgp160 transgene. The morphological findings at 3 months are subtle and are dominated by a watery, dendritic degeneration and a reactive gliosis. At 12 months, the evidence of neuronal degeneration and loss is present along with various degenerative phenomena involving synapses, dendrites and axons, including axonal swellings. Cytoskeletal abnormalities were found by immunohistochemistry. Chronic inflammation was also observed in the leptomeninges of the spinal cord and brainstem and in the cerebellar white matter. These models thus offer an exciting sequence of morphological findings initiated by the neuronal expression of the HIV-1 env proteins and offer a different tool to explore the neuronal dysfunction in AIDS.

HIV dementia: the role of the basal ganglia and dopaminergic systems

The clinical features of human immunodeficiency virus (HIV) dementia exhibit the hallmarks of a subcortical dementia. These features include psychomotor slowing, apathy, bradykinesia and altered posture and gait similar to those observed in advanced Parkinson's disease. The dementia has the hallmarks attributed to subcortical dementia. The exquisite sensitivity of many of these patients to dopamine receptor blockade suggested a profound and, perhaps, selective abnormality of striatal dopaminergic systems. Additional investigations, electrophysiological, pathological, virological, metabolic and radiological studies, indicate that the basal ganglia are a major target of HIV infection. In this review, we describe the evidence for involvement of basal ganglia and, in particular, the dopaminergic systems, in HIV dementia. We also suggest novel therapeutic strategies that may be beneficial in the treatment of this disorder.

Epidemiology and clinical features of HIV-1 associated neuropathies

Peripheral neuropathy is common in human immunodeficiency virus type-1 (HIV-1) infection. Peripheral neuropathies complicate all stages of the HIV-1 disease and cause considerable morbidity and disability in HIV-1 infected individuals and acquired immunodeficiency syndrome (AIDS) patients. Whereas symptomatic neuropathies occur in approximately 10% to 15% of HIV-1-infected patients overall, pathologic evidence of peripheral nerve involvement is present in virtually all end-stage AIDS patients. There are 6 major clinical types of HIV-associated neuropathies that are regularly seen in large HIV-1 clinics. Distal sensory polyneuropathy (DSP) is the most common among the HIV-1-associated neuropathies. DSP generally occurs in later stages of HIV-1 infection and it follows an indolent and protracted clinical course. The dominant clinical features in DSP include distal pain, paresthesia and numbness in a typical length-dependent fashion with proximal to distal gradient. Whereas toxic neuropathies--secondary to certain antiretroviral agents--are clinically similar to DSP, their temporal relation to neurotoxic medication helps distinguish them from other HIV-1-associated neuropathies. DSP and toxic neuropathy may coexist in a single patient. Acute and chronic inflammatory demyelinating polyradiculoneuropathies (AIDP and CIDP) produce global limb weakness. AIDP may occur at seroconversion and it can therefore be the initial manifestation of HIV-1 infection. CIDP generally occurs in the mid to late stages of HIV-1 infection. Progressive polyradiculopathy (PP) occurs in patients with advanced immunodeficiency and is generally caused by the opportunist cytomegalovirus (CMV) infection. Mononeuropathy multiplex (MM) in early stages of HIV-1 infection is immune mediated, whereas in advanced AIDS it is caused by the CMV infection. Finally, subclinical autonomic nervous system involvement is common in all stages of HIV-1 infection. Because HIV-1-associated neuropathies are diverse in their etiology and pathogenesis, a precise clinical diagnosis is required to formulate a rational therapeutic intervention.

HIV-1-associated central nervous system dysfunction

Despite more than 15 years of extensive investigative efforts, a complete understanding of the neurological consequences of HIV-1 CNS infection remains elusive. Although the resources of numerous investigators have been focused on studies of HIV-1-associated CNS disease, the complex nature of the disease processes that underlie the clinical, pathological, and cellular manifestations of HIV-1 CNS infection have required a larger volume of studies than was initially envisioned. Several major areas remain as the focus of current research efforts. One of the more pressing issues facing researchers and clinicians alike is the search for correlates to the development of HIV-1-associated CNS neuropathology and the onset of HIVD. Although numerous parameters have been studied, none have been shown to be absolute predictors or markers of HIV-1-related CNS dysfunction. The identification of solid correlates of HIVD is an important goal that would permit clinical identification of individuals at risk for developing potentially crippling, life-threatening CNS abnormalities and would facilitate early treatment of nascent neurological problems. A more complete comprehension of the cellular foundations of CNS dysfunction and HIVD is also a fundamental part of strategies designed to treat or prevent HIV-1-associated CNS disease. Future investigations will strive to expand the body of knowledge concerning the complex interactions between infected and uninfected neuroglial cells and the roles of numerous cytokines, chemokines, and other soluble agents that are deregulated during HIV-1 CNS infection. In particular, a thorough understanding of the mechanisms of neurotoxicity may facilitate the development of new therapies that alleviate or eliminate the clinical consequences of CNS infection. Finally, investigators will continue to study HIVD within the context of single and combination drug therapies used in the treatment of HIV-1 infection and AIDS. As newer and more effective systemic treatments for HIV-1 infection and AIDS are introduced, the effects of these treatments on the onset, incidence, and severity of HIVD will also require intensive study. The impact of drug therapies on the ability of the CNS to act as an HIV-1 reservoir will also need to be addressed. Introduction of each new drug or drug combination will necessitate studies of drug penetration into the CNS and efficacy against the development of CNS abnormalities. Furthermore, as more effective treatments prolong the lifespan of individuals infected with HIV-1, the impact of extended survival on the occurrence and severity of HIVD will also require further investigations. The quest for answers to these and other questions will be complicated by the diversity of experimental systems used to study different aspects of HIV-1 CNS infection and HIVD. Each system has its own unique strengths and weaknesses. Clinical observations provide a continuous spectrum of symptomatic findings but reveal little about the underlying mechanisms of disease. In vivo imaging techniques, such as CT and MRI, also provide a continuum of observations, but the images are limited in their resolution. Neuropathological examinations of postmortem HIV-1-infected brains offer gross, cellular, and molecular views (including phenotypic and genotypic analyses of CNS viral isolates) of the diseased brain, but only provide a snapshot of the end-stage neurologic dysfunction. Studies that rely on animal surrogates for HIV-1, including SIV, simian-HIV (SHIV), feline immunodeficiency virus (FIV), visna virus, and HIV-1 SCID-hu models, permit experimental protocols that cannot be carried out in humans, but are limited by the fidelity with which each virus and animal model emulates the conditions and events observed in the human host. Finally, in vitro techniques, which include the use of primary cells and cell lines, adult or fetal human cell cultures, and BBB barrier model systems, are also convenient means by which aspe

Gabapentin in painful HIV-related neuropathy: a report of 19 patients, preliminary observations

The objective of this study was to assess the efficacy and safety of Gabapentin as the sole analgesic in patients with HIV-related painful neuropathy. Nineteen patients with HIV-related painful neuropathy were administered Gabapentin. Efficacy was evaluated with two 100-mm Visual Analogue Scales (VAS) (0: no symptom; 100: worst symptom), rating pain and interference of pain with sleep, performed at baseline and monthly intervals. Main Pain VAS score decreased from a baseline of 55.7 +/- 19.1 mm to a final 14.7 +/- 18.6 mm (ANOVA P = 0.0001) and mean Sleep Interference VAS score decreased from a baseline of 60.4 +/- 31.9 mm to a final 15.5 +/- 27.7 mm (ANOVA P = 0.0001). Gabapentin provided significant pain relief in our patients with HIV-associated painful sensory neuropathy.

MIKADO: a multicentre, open-label pilot study to evaluate the antiretroviral activity and safety of saquinavir with stavudine and zalcitabine

BACKGROUND

Since eradication of HIV is unlikely, long-term management of the disease necessitates careful evaluation of the combinations of currently available drugs to determine the most potent and useful rational sequencing of regimens.

OBJECTIVE

To determine the antiretroviral efficacy and tolerability of saquinavir soft gelatin capsule (SQV-SGC) plus zalcitabine (ddC) and stavudine (d4T), as first-line treatment in HIV-infected patients.

DESIGN

Multicentre, open-label, non-comparative study.

PATIENTS AND METHODS

Thirty-five asymptomatic, HIV-infected adults with no prior antiretroviral treatment, a CD4 count > or =250 cells/microL and baseline > or = 5000 HIV RNA copies/mL were included in the study. Patients received SQV-SGC 1200 mg three times a day (tid), ddC 0.75 mg tid and d4T 30 or 40 mg twice a day (bid) for 24 weeks. Plasma HIV RNA, CD4 and CD8 cell counts, HIV reverse transcriptase and protease resistance genotypes, SQV plasma concentration and tolerability were evaluated.

RESULTS

At baseline, median HIV RNA (interquartile range) was 4.99 (4.81-5.48) log10 copies/mL, and median CD4 count was 370 (318-504) cells/microL (n = 35). At week 24, the median decrease in HIV RNA was 3.05 (2.19-3.68) log10 copies/mL. A viral load below the level of quantification (200 copies/mL and 20 copies/mL) was achieved in 63% and 34% of patients, respectively (intent-to-treat analysis). The only mutations detected were L90M substitutions in two patients. At week 24, the median CD4 count increased (P < 0.0001), and CD8 cell counts decreased (P < 0.0001), relative to baseline. In total, there were five cases of peripheral neuropathy (14%). Mean triglyceride and cholesterol levels remained within normal ranges.

CONCLUSIONS

Triple therapy with SQV-SGC plus ddC and d4T is a reasonably well tolerated regimen that markedly and rapidly reduces viral load with immunological improvement. This combination is an effective additional therapeutic option, with an efficacy that compares favourably to other triple regimens used in HIV treatment.

Can antiglycolipid antibodies present in HIV-infected individuals induce immune demyelination?

Of the eight clinically defined neuropathies associated with HIV infection, there is compelling evidence that acute and chronic inflammatory demyelinating polyneuropathy (IDPN) have an autoimmune pathogenesis. Many non-HIV infected individuals who suffer from sensory-motor nerve dysfunction have autoimmune indicators. The immunopathogenesis of demyelination must involve neuritogenic components in myelin. The various antigens suspected to play a role in HIV-seronegative IDPN include (i) P2 protein; (ii) sulfatide (GalS); (iii) various gangliosides (especially GM1); (iv) galactocerebroside (GalC); and (v) glycoproteins or glycolipids with the carbohydrate epitope glucuronyl-3-sulfate. These glycoproteins or glycolipids may be individually targeted, or an immune attack may be raised against a combination of any of these epitopes. The glycolipids, however, especially GalS, have recently evoked much interest as mediators of immune events underlying both non-HIV and HIV-associated demyelinating neuropathies. The present review outlines the recent research findings of antiglycolipid antibodies present in HIV-infected patients with and without peripheral nerve dysfunction, in an attempt to arrive at some consensus as to whether these antibodies may play a role in the immunopathogenesis of HIV-associated inflammatory demyelinating polyneuropathy.

Stroke: epidemiology, clinical picture, and risk factors--Part I of III

The aim of this review is to present the current knowledge regarding stroke. It will appear in three parts (in part II the pathogenesis, investigations, and prognosis will be presented, while part III will consist of the management and rehabilitation). In the current part (I) the definitions of the clinical picture are presented. These include: amaurosis fugax, vertebrobasilar transient ischemic attack, and stroke (with good recovery, in evolution and complete). The role of the following risk factors is discussed in detail: age, gender, ethnicity, heredity, hypertension, cigarette smoking, hyperlipidemia, diabetes mellitus, obesity, fibrinogen and clotting factors, oral contraceptives, erythrocytosis and hematocrit level, prior cerebrovascular and other diseases, physical inactivity, diet and alcohol consumption, illicit drug use, and genetic predisposition. In particular, regarding the carotid arteries, the following characteristics are analyzed: atheroma, carotid plaque echomorphology, carotid stenosis, presence of ulcer, local variations in surface deformability, pathological characteristics, and dissection. Finally the significance of the cerebral collateral circulation and the conditions predisposing to cardioembolism and to cerebral hemorrhage are presented.

Cognitive function in HIV-1-infected drug users

Loss of cognitive ability, the most common neuropsychological complication in HIV-1 disease, may influence compliance with treatment and has been associated with decreased functional capacity, as well as an increased risk of mortality. In HIV-1-infected drug users, cognitive impairment affecting attention, memory, planning of complex tasks, information processing, and motor processes, has been reported, similar to findings in predominantly HIV-1-infected nondrug-using cohorts. The issue of whether early signs of cognitive dysfunction can be identified in asymptomatic HIV-1-infected drug users remains controversial. Evaluation of potential confounding factors, such as drug abuse, age, education, nutritional status, which may influence cognitive function, is essential for determining the dominant cause of neuropsychological abnormalities. There is evidence for a time-limited, protective effect against the development of AIDS dementia with zidovudine therapy. The potential ability of other therapies (e.g., antioxidants, B-complex vitamins) to prevent neuronal damage and protect the brain remains to be determined.

Cerebral infarction in adult AIDS patients: observations from the Edinburgh HIV Autopsy Cohort

BACKGROUND AND PURPOSE

Autopsy series of patients with AIDS have found a 4% to 29% prevalence of cerebral infarction. Little is known of the prevalence of cerebral infarction when not associated with non-HIV central nervous system (CNS) infection, lymphoma, or cardioembolic sources. Clinical correlation has seldom been available. We describe the pathological and clinical features of patients from the Edinburgh HIV Cohort Study found to have had cerebral infarcts without evidence of non-HIV CNS infection, CNS lymphoma, or cardioembolic sources at autopsy.

METHODS

From 183 autopsy cases, 26 without evidence of opportunistic cerebral infection or lymphoma were selected. These 26 cases went through a second selection process in which the presence of cerebral infarction, in the absence of the conditions mentioned, was verified. Histology and clinical records for the remaining patients were reviewed.

RESULTS

Ten (5.5%) cases fulfilled the inclusion criteria and demonstrated similar hypoxic-ischemic lesions. Small-vessel thickening was seen in all cases, and perivascular space dilatation, rarefaction, and pigment deposition, with vessel wall mineralization and perivascular inflammatory cell infiltrates, were seen in some cases. Vasculitis was not found. One patient had had a transient ischemic attack, and no patient had had a stroke.

CONCLUSIONS

Cerebral infarcts in HIV-infected patients are not common in the absence of cerebral non-HIV infection, lymphoma, or embolic sources. We found an HIV-associated vasculopathy with similar features in all risk groups. In AIDS patients presenting with stroke or transient ischemic attack, potentially treatable causes, such as cerebral coinfection or tumor, should be sought.

HIV/AIDS-related Pain as a Chronic Pain Condition: Implications of a Biopsychosocial Model for Comprehensive Assessment and Effective Management

This paper reviews the current literature focusing on pain in HIV/AIDS, including prevalence, pathophysiology, substance abuse, treatment issues, and psychosocial contributions. In light of the high prevalence of pain among individuals with HIV/AIDS, attention is paid to the negative psychosocial impacts of pain in this population and to psychosocial barriers to optimal HIV/AIDS-related pain treatment. The paper conceptualizes HIV/AIDS pain as chronic pain. Subsequently, a biopsychosocial model of chronic pain assessment and treatment is applied. A multidimensional framework is presented for appropriate assessment and treatment of HIV/AIDS patients with pain, and specific recommendations and guidelines are offered for assessment and multimodal treatment of HIV/AIDS-related pain informed by the model.

Phagocytosis of neuronal or glial debris by microglial cells: upregulation of MHC class II expression and multinuclear giant cell formation in vitro

Most CNS pathologies are accompanied by the occurrence of activated, phagocytic microglial cells. We intended to investigate whether (1) isolated microglial cells removed from the CNS cytokine network sustain their capacity to acquire an activated phenotype when challenged with cellular or noncellular debris; and (2) different substrates lead to different patterns of microglial activation. It was observed that although removed from their usual surroundings microglial cells preserve their ability to transform to an amoeboid morphology, form multinucleated giant cells, and enhance their expression of MHC class II when exposed to membranes of neuronal or glial origin. Furthermore, cellular substrates derived from primary hippocampal neuronal cultures, neuroblastic cells (B50), or glial cells were all able to induce similar morphological changes and enhanced expression of MHC class II. In contrast, phagocytosis of Latex beads induced an amoeboid morphology but no increase in the expression of immunologically relevant molecules. Interferon-beta (IFN-beta), a substance clinically used in the treatment of the relapsing-remitting form of multiple sclerosis, was shown to inhibit the phagocytosis-induced upregulation of MHC-class II. In summary, phagocytic microglial cells are independent from the CNS cytokine network in their transition from a resting to an activated phenotype; and different cellular substrates, regardless whether they are of neuronal, glial, or even malignant origin, result in similar morphological and functional changes.

Human immunodeficiency virus glycoprotein 160 induces cytokine mRNA expression in the rat central nervous system

1. Elevated proinflammatory cytokines within the central nervous system (CNS) of individuals infected with human immunodeficiency virus (HIV) may contribute to altered CNS processes prior to the onset of AIDS. Most studies of HIV-induced alterations in cytokine expression within the CNS have focused on interleukin (IL)-1 and tumor necrosis factor (TNF). 2. We used a ribonuclease protection assay (RPA) to elucidate further the pattern of cytokine mRNA expression in the rat CNS in response to HIV envelope glycoprotein 160 (gp160). Male Sprague-Dawley rats were surgically implanted with a guide cannula directed into a lateral cerebral ventricle. HIV gp160 was injected intracerebroventricularly and rats were sacrificed immediately (time = 0) or at 1, 2, or 4 hr postinjection. Discrete brain regions were dissected, and peripheral glands removed. All tissues were frozen in liquid nitrogen until RNA extraction and assay. 3. IL-1beta IL-1alpha, TNF-alpha, and TNFbeta mRNAs were constitutively expressed in brain tissues. Central administration of gp160 dramatically increased mRNA expression for IL-1beta and TNFalpha in the hypothalamus, hippocampus, brainstem, and cerebellum. Furthermore, although mRNA expression for IL-5, IL-6, and IL-10 was never detected under basal conditions, these mRNAs were increased in brain tissue after administration of gp160. Peak expression in each brain region was detected 2 hr after administration. Multiple cytokine mRNAs were detected in peripheral tissues, but their expression was not altered by central administration of gp160. 4. Our results indicate that gp160 induces mRNA expression in brain for cytokines other than IL-1 and TNF. Screening for multiple cytokine mRNA in this manner provides extensive information concerning the particular cytokines that may be involved in HIV-induced pathologies and alterations in CNS processes.