HIV dementia and apolipoprotein E

The effect of apolipoprotein E genotypes on the occurrence of HIV dementia and HIV encephalitis was studied in a sample of 132 AIDS patients in whom clinical data on dementia was available and full autopsy had been performed. There was no statistically significant correlation between risk of HIV dementia or HIV encephalitis in relation to apolipoprotein E genotypes, even after correction for length of survival with AIDS and antiretroviral treatment.     

Accumulation of β-amyloid precursor protein in HIV encephalitis: Relationship with neuropsychological abnormalities

The pathogenesis of neuropsychological abnormalities in patients with human immunodeficiency virus type 1 (HIV-1) encephalitis is obscure because neurons are not the target of infection and severe neuronal loss occurs only late during the disease. Moreover, there is evidence indicating that HIV dementia is not a homogeneous entity and could partially reverse after treatment with zidovudine. The finding that impaired axonal flow, evidenced by β-amyloid precursor protein immunoreactivity, could contribute to the neuropsychological deficits prompted the present study. Brains of patients with full-blown acquired immunodeficiency syndrome (AIDS) were studied and findings compared with those of normal and abnormal control subjects. The presence of HIV-1 DNA was investigated by nested polymerase chain reaction; axonal abnormalities were detected by β-amyloid precursor protein, ubiquitin immunohistochemistry, and silver staining. Accumulation of β-amyloid precursor protein was observed in all the HIV encephalitis brains studied; the appearance of the immunostaining varied from globular structures to bundles of parallel formations. In 2 AIDS brains without pathological abnormalities, only the latter pattern was detected. The brains with trauma were strongly reactive with β-amyloid precursor protein antibody and the different reactivity within them correlated with posttrauma survival, only globular structures being detected in the older cases. No correlation was found between the different pattern of β-amyloid precursor protein reactivity and dementia in AIDS patients. These results show that widespread axonal injury is a constant feature in AIDS brains and suggest that it could play a role in the pathogenesis of the neuropsychological abnormalities of these patients.     

Human immunodeficiency virus encephalitis is the pathological correlate of dementia in acquired immunodeficiency syndrome

While dementia has been observed in approximately one-fourth of terminally ill patients with acquired immunodeficiency syndrome, it has been difficult to attribute this clinical disorder to a single neuropathological substrate. We used a simple and readily reproducible scale for estimating the burden of human immunodeficiency virus (HIV) in the central nervous system (i.e., severity of HIV encephalitis) and compared this to autopsy neurological summaries of dementia. Like others, we found that multinucleated giant cells were present in only half of the dementia patients. However, all of the dementia patients had severe HIV encephalitis as assessed by measurements of intra–central nervous system viral burden. Additional patients had severe HIV encephalitis without clinical histories of dementia. We interpret these latter findings as evidence that HIV encephalitis exists for a period of time before the clinical symptomatology develops. Comparison of presence or absence of concurrent cytomegalovirus encephalitis showed no association with dementia.     

Quantitation of human immunodeficiency virus in brains of demented and nondemented patients with acquired immunodeficiency syndrome

We measured human immunodeficiency virus (HIV) DNA in brains of 15 patients who died with acquired immunodeficiency syndrome (AIDS). All had been followed prospectively prior to death; 7 were demented and 8 were not demented. HIV was detected in 13 of 15 brains by polymerase chain reaction (PCR) and in the remaining 2 by presence of viral RNA or viral antigen. Quantitative PCR showed a wide range in amounts of HIV DNA with no significant difference between brains of demented and nondemented patients. These results suggest that qualitative features of the virus, rather than increased virus load per se, may be responsible for the clinical differences between HIV-infected patients with and without dementia.     

Parkinsonism in HIV dementia

Summary. A great number of human immunodeficiency virus (HIV)-infected patients develop a central nervous system disorder, commonly called HIV dementia or AIDS dementia complex (ADC). HIV dementia is independent of opportunistic infections and is due to the virus itself. Symptoms include psychomotor slowing, apathy and motor disorders similar tothe bradykinesia and postural and gait abnormalities observed in late Parkinson's disease. Consequently, HIV has been discussed during the last few years as an additional cause for parkinsonism, and parkinsonian syndromes as manifestations of HIV dementia. Moreover, the early phase of HIV infection gains increasing interest because of studies which report subtle neurological symptoms at this stage. Accordingly, we found in SIV-infected monkeys that dopamine is reduced by 44% within as few as two months of infection, indicating that changes during early infection must be thoroughly evaluated. In this short review, we discuss alterations in the nigrostriatal dopaminergic system during early and late immunodeficiency virus infection and the common clinical and biochemical features shared by HIV dementia and Parkinson's disease. Received January 15, 2002; accepted January 24, 2002     

Spectrum of human immunodeficiency virus-associated neocortical damage.

A spectrum of neurocognitive defects, termed human immunodeficiency virus type 1 (HIV-1)-associated cognitive/motor complex, has been described in patients with acquired immunodeficiency syndrome (AIDS). AIDS dementia complex (ADC) is a severe form of this disease seen in 20 to 30% of terminally ill patients. The etiology of this complex is distinct from commonly observed opportunistic infections seen in brains of patients with AIDS and has been attributed to HIV infection within the brain. At autopsy, the brains of patients with ADC contain numerous HIV-infected macrophages/microglia with prominent subcortical damage, together termed HIV encephalitis. We retrospectively analyzed all 107 brains from a three-year period (1988-1990) of AIDS autopsies using immunocytochemistry to detect HIV. Rather than breaking into distinct groups of HIV encephalitis versus non-HIV encephalitis, the specimens revealed a spectrum of severity of HIV infection. Although only 16% of the brains showed the histological hallmarks of HIV encephalitis, more than 50% of the autopsies showed moderate to severe HIV infection. In a subset of 23 AIDS autopsies during which short postmortem times and absence of significant opportunistic infection permitted quantitative analysis of dendritic and synaptic complexities, we identified a strong correlation between neocortical dendritic and presynaptic damage and abundance of HIV envelope protein in the neocortical gray and deep white matter. This correlation suggests that the presence of HIV-1 in the neocortex may be responsible by direct or indirect mechanisms for dendritic and synaptic damage.     

Prothrombotic states in HIV disease and stroke complications

Thirty to 40% of patients with acquired immunodeficiency syndrome (AIDS) have symptoms and signs of neurologic dysfunction. Radiographic and pathologic studies reveal evidence of neurologic involvement in 75% to 90% of cases of advanced-stage human immunodeficiency virus-1 (HIV) disease. Before the introduction of highly active antiretroviral therapies, AIDS dementia complex and opportunistic infections of the central nervous system were frequent causes of global cerebral dysfunction. Focal neurological deficits were most commonly due to toxoplasmosis, primary central nervous system (CNS) lymphoma, or progressive multifocal leukoencephalopathy.Thrombotic events including cerebral infarction and venous thrombosis have been reported in patients with HIV/AIDS. Various hematologic abnormalities have been described that could lead to a hypercoagulable state, including antiphospholipid antibodies; deficiencies of antithrombin III, protein C, and protein S; and increased levels of von Willebrand factor and D-dimer.In the majority of cases of cerebral infarction, there is an associated precipitating event such as opportunistic infection or malignancy. However, vasculopathy has also been described in both adults and children. Furthermore, there are reports of HIV patients with cerebral infarction in whom an HIV-related coagulopathy is identified and other cases where no explanation is found, but only a limited hematologic evaluation has been performed.     

The Neuropathology of HIV/AIDS

The introduction of Highly Active Anti-retroviral Therapy (HAART) has resulted in significant decreases in morbidity and mortality for subjects infected with HIV. The brain is a major target organ for HIV resulting in significant neuropathological changes in most HIV infected subjects and a wide range of clinical neurological symptoms including HIV associated dementia. In the pre-HAART era HIV associated dementia was a common complication of AIDS. However, since the introduction of HAART the incidence of HIV associated dementia has fallen, but the prevelance has actually risen due to the increasing number of infected subjects and increased life expectancy. HIV associated dementia correlates most closely with neuroinflammation rather than directly with viral load or HIV encephalitis. HIV related clinical and neuropathological disorders are more prevalent in drug abusers than in other risk groups. This review focuses on the shifting pathology observed in HIV infected subjects since the introduction of HAART, discussing the clinical manifestations of these and the influence of confounding factors such as drug abuse and Hepatitis C co-infection.     

Damage and repair of DNA in HIV encephalitis

Neuronal damage and dementia are common sequelae of HIV encephalitis. The mechanism by which HIV infection of CNS macrophages results in neuronal damage is not known. We examined the brains from 15 AIDS autopsies (8 with HIV encephalitis and 7 without) and 4 non-infected control autopsies for the presence of DNA strand breaks, for associated changes in the expression of the DNA repair enzymes KU80 and Poly (ADP-ribose) polymerase (PARP), and for accumulation of amyloid precursor protein (APP). Abundant DNA damage was observed with terminal transferase-mediated dUTP nick end-labeling (TUNEL), however, there was no morphologic evidence of significant neuroglial apoptosis. The DNA repair enzyme KU80 was immunocytochemically detectable in neuronal and glial cells in autopsy brains from patients with and without HIV encephalitis; however, in cases with HIV encephalitis the staining was more prominent than in the infected or non-infected controls without encephalitis. There was no difference in KU80 immunostaining in oligodendroglia from autopsies with and without encephalitis. Immunostaining for PARP was more intense in gray and white matter of cases with HIV encephalitis. No clear spatial relationship existed between expression of DNA repair enzymes and the spatial proximity of microglial nodules or HIV-infected macrophages. The cytoplasm of cortical and subcortical neurons immunostained for APP Stronger cortical neuronal APP staining was observed in cases without HIV encephalitis. Staining of deep gray matter neurons was similar, irrespective of the presence or absence of encephalitis. While foci of intense APP staining were noted in white matter not related to HIV infection, they were associated with foci of opportunistic infections (e.g. due to CMV or PML). We conclude that damaged DNA and altered patterns of expression of DNA repair proteins and APP are common findings in the brains of AIDS patients at autopsy, but do not have a spatial relationship to HIV-infected macrophages.     

The changing pattern of HIV neuropathology in the HAART era

Highly active antiretroviral treatment (HAART), which has been available for most AIDS patients in France since 1996, has resulted in a dramatic improvement of the progression of the disease. From the survey of our series of 343 brains with acquired immunodeficiency syndrome (AIDS) from patients who died between 1985 and 2002, we found both quantitative and qualitative changes in the pattern of human immunodeficiency virus (HIV) neuropathology. Quantitatively, despite a dramatic decrease in the number of autopsies, brain involvement remained a major cause of death. There was an overall decrease in incidence of cerebral toxoplasmosis, cytomegalovirus encephalitis (CMVE), and HIV encephalitis (HIVE), for which successful treatment is available. This contrasted with the unchanged incidence of progressive multifocal leukoencephalopathy (PML) and malignant non-Hodgkin lymphomas (MNHL). However, when looking closer at the 3 last years, the incidence of diseases affecting patients with severe immunodepression (CMVE, PML, and MNHL) decreased between 2000 and 2002, whereas infections occurring in patients with milder immunodeficiency, toxoplasmosis, varicella-zoster encephalitis (VZVE), or herpes simplex virus encephalitis (HSVE) became more frequent. In addition, we found uncommon types of brain infection such as BK virus encephalitis or general paresis. Finally, we described new variants of HIVE: severe leukoencephalopathy with intense perivascular macrophage and lymphocyte infiltration, possibly due to an exaggerated response from a newly reconstituted immune system, and chronic "burnt out" forms of HIVE as VZVE, toxoplasmosis, or PML, possibly associated with prolonged survival, in which neither inflammation nor organisms could be detected. These findings are compared with those reported in other neuropathological studies from different developed countries.     

The central nervous system and HIV infection

Human immunodeficiency virus (HIV) may be the cause of both primary and secondary brain diseases. In this review general features of HIV-associated neuropathology are discussed. Up to 90% of patients with AIDS have a variety of HIV-related brain diseases. Primary brain diseases including lymphocytic meningitis and HIV encephalitis are attributed directly to the effect of the virus on the brain. Secondary diseases including toxoplasmosis, cryptococcosis, primary leukoencephalopathies and lymphomas result from these patients' immunodeficiency status.     

CSF protein and cellular profiles in various stages of HIV infection related to neurological manifestations

CSF protein and cellular profiles were studied in 28 HIV-infected patients. Twenty of them had neurological complaints, but only 6 patients had objective neurological deficits such as dementia, ocular motility disorders or polyneuropathy. The serum/CSF HIV antibody ratio was on average lowest in acquired immunodeficiency syndrome (AIDS) (4 patients) and highest or almost normal in lymphadenopathy syndrome (LAS) (11) and asymptomatic seropositivity (ASX) (7), while it varied between these extremes in AIDS-related complex (ARC) (6). However, low values of the ratio were also found in the HIV-infected patients free of neurological symptoms and even in one ASX patient. The CSF IgG index was elevated in all these 4 general stages of HIV infection without any significant differences between them. The CSF/serum albumin ratio was slightly increased in patients with neurological deficits, but this ratio showed no association with any other clinical factor analysed. CSF leucocytes were increased in the early stages of the disease, but later the cellular reaction subsided. HIV was isolated from post mortem brain tissue of two AIDS patients and from the CSF of one of them. The results suggest increased intrathecal virus-specific IgG synthesis, not only in patients with neurological deficits and at advanced stages of infection, but also in neurologically symptom-free subjects and at early infection. The lack of correlation between the increased virus-specific IgG synthesis within the CNS and the presence of neurological symptoms suggests that neurologically "silent" areas of brain white matter are often affected in HIV infection.     

Human immunodeficiency virus antibodies in cerebrospinal fluid

The relative concentrations of human immunodeficiency virus (HIV) antibodies in relation to equal IgG contents of 46 serum cerebrospinal fluid (CSF) samples from 32 patients were determined by serial dilution in an anti-HIV enzyme-linked immunosorbent assay (ELISA). The ratio of CSF and the serum HIV antibody concentration was expressed as Q_HIV = CSF dilution/serum dilution. Q_HIV is regarded as a parameter for specific intrathecal HIV antibody production. The Q_HIV ranged from 0.7 to 16. Six of seven patients with clinical signs of acquired immunodeficiency syndrome (AIDS)-related dementia (ARD), but only seven of 25 patients without clinical diagnosis of ARD showed a Q_HIV > 2.     

Psychopharmacotherapy of psychiatric syndromes in asymptomatic and symptomatic HIV infection

It is evident that human immunodeficiency virus (HIV) infection is one of the most serious public health issues in decades. HIV infection compromises cell-mediated immunity which ultimately may result in the acquired immunodeficiency syndrome (AIDS). AIDS, to date, remains an incurable and progressively fatal disorder. HIV infection is spreading beyond the originally identified high-prevalence groups of gay/bisexual males, intravenous drug abusers, and recipients of infected blood or blood products. Today, more and more heterosexual males, women, adolescents, and children have been infected with this lethal virus. This report addresses some of the psychiatric complications associated with HIV infection and discusses the diagnostic and clinical management challenges that clinicians must face as they deal with the increasing population of HIV-infected patients. Depression, anxiety, psychosis, delirium, and dementia are commonly encountered disorders associated with HIV spectrum disorders which must be accurately identified and can be effectively managed with psychopharmacological interventions.     

Characterization of human immunodeficiency virus (HIV)-infected cells in infiltrates associated with CNS opportunistic infections in patients with HIV clade C infection

Infection with human immunodeficiency virus (HIV) clade C is the most common HIV infection worldwide, yet its impact on the nervous system remains largely unknown. Autopsy studies from regions affected by this virus are scarce, and HIV dementia has only rarely been reported from these countries. Most patients who develop neurologic complications die of opportunistic infections. We thus conducted a neuropathologic study from a single institution in India to characterize the HIV-infected cells in the inflammatory infiltrates in a total of 15 cases (5 patients each who died of either CNS toxoplasmosis, tuberculosis, or cryptococcal meningitis). Nearly, all patients had HIV-infected cells in the brain, although these cells were most abundant in patients with toxoplasma encephalitis. Interestingly, none of the patients had any multinucleated giant cells. HIV-infected cells were found in the parenchyma, perivascular regions, and choroid plexus and found infiltrating the parenchyma from the meninges, suggesting multiple portals of entry into the brain. These findings suggest the possibility that patients, even if successfully treated for an opportunistic inflection, may be at high risk of developing HIV encephalitis and subsequent dementia.     

Neuropathology of the acquired immune deficiency syndrome (AIDS): report of 39 autopsies from Vancouver, British Columbia.

Neuropathological findings from 39 acquired immune deficiency syndrome (AIDS) autopsies of primarily neurologically symptomatic patients and 7 brain biopsies from AIDS patients performed at St. Paul's Hospital, Vancouver, British Columbia are reported. Autopsy findings included human immunodeficiency virus-1 (HIV)-type multinucleated giant cell (MNGC)-associated encephalitis seen in 17 patients, toxoplasmosis in 7 patients, and cytomegalovirus encephalitis and/or microglial nodule-associated nuclear inclusions in brain parenchyma in 9 patients. Central nervous system lymphoma was identified in 11 autopsy patients and in 4 of 7 brain biopsies. Infectious processes including HIV encephalitis were seen in 10 of 11 autopsied patients with lymphoproliferative lesions in the brain parenchyma, while 40% of patients without lymphoma had HIV-type MNGC or opportunistic infections. CNS lymphoma was not significantly increased in incidence in patients with a clinical history of zidovudine treatment, but increased duration of survival after the diagnosis of AIDS was associated with increased incidence of lymphoma in both untreated and zidovudine-treated patients. Patients displaying HIV MNGC within microglial nodules had a shorter mean duration of survival after diagnosis of AIDS than those patients with HIV encephalitis with dispersed MNGC, white matter vacuolation, and gliosis.     

Cytomegalovirus (CMV) encephalomyeloradiculitis and human immunodeficiency virus (HIV) encephalitis: presence of HIV and CMV co-infected multinucleated giant cells

Summary A 25-year-old homosexual male with AIDS presented with a cauda equina syndrome clinically suggestive of cytomegalovirus (CMV) myeloradiculitis. He was treated with ganciclovir with transient improvement of neurological signs and died 4 months after onset of neurological signs. Neuropathological examination revealed human immunodeficiency virus (HIV) encephalitis, CMV subependymal encephalitis and CMV myeloradiculitis. The latter was characterised by myelin loss, Schwann cell proliferation and presence of CMV early antigens in the nuclei of S-100 protein-positive cells in the spinal roots. In the subependymal regions, morphologically characteristic multinucleated giant cells, positive for CD68, contained early CMV antigens (E13) in their nuclei and HIV antigens (gp41 and p24) in their cytoplasm. The observation that HIV and CMV can co-infect the same cell in vivo raises the possibility of a direct synergistic interaction of both viruses at cell level. This suggests that CMV may play a role as a co-factor in the pathogenesis of HIV encephalopathy.Supported by a grant from Agence Nationale pour la Recherche sur le SIDA and Medical Research Council. This case was the subject of preliminary communications at the 77th meeting of the British Neuropathological Society, London, January 1989 (16, case 2) and at the French-German joint meeting for Neuropathology, Frankfurt am Main, October 1989 (17, case 2)     

Incidence and prevalence of neurological disorders associated with HIV since the introduction of highly active antiretroviral therapy (HAART)

OBJECTIVE: To determine the change of incidence and prevalence of neurological disorders caused by the human immunodeficiency virus (HIV) and opportunistic infections in HIV positive patients under treatment since the introduction of highly active antiretroviral therapy (HAART). METHODS: The data of all HIV infected patients were retrospectively analysed, who were examined in the HIV outpatients clinic of the neurological department of the University Clinic Essen between 1995 and 1998 (n=563, total number of visits=735). Data from identified patients were divided into two groups according to the time of examination from 1995 to 1996 (334 visits) and from 1997 to 1998 (401 visits). The incidence and prevalence of neurological disorders were statistically compared between both time intervals. RESULTS: Significantly more patients received HAART in 1997-8 (p<0. 001) and mean CD4+ cell count was significantly higher in 1997-8 (p<0.001). The prevalence of HIV associated dementia and HIV associated polyneuropathy were significantly lower in 1997-8 (both: p=0.02) and the incidence of toxoplasma encephalitis decreased from 5.7% in 1995-6 to 2.2% in 1997-8 (p=0.015). Based on the small number of patients significant changes in HIV associated myopathy, progressive multifocal leukoencephalopathy, cryptoccocal meningitis, and cytomegalovirus-encephalitis could not be detected. CONCLUSION: The prevalence of the most frequent HIV associated neurological disorders and incidence of toxoplasma encephalitis decreased since the introduction of HAART. This may be due to the improvement of immunostatus by HAART as demonstrated by the higher CD4+ cell count in the later time interval. Direct antiretroviral effects within the nervous system may be considered causative as well. The prevalence and incidence of HIV associated neurological disorders and opportunistic CNS infections decreased after introduction of HAART.     

Eye movement abnormalities as a predictor of the acquired immunodeficiency syndrome dementia complex

Using infrared oculography, we recorded the eye movements in a group of patients with acquired immunodeficiency syndrome (AIDS), with or without the AIDS dementia complex (ADC). Our aim was to determine whether the severity of dementia could be correlated with abnormalities of eye movement and whether eye movement abnormalities could be detected prior to the onset of clinical dementia. Abnormalities of eye movement were present in seven of seven patients with mild, moderate, or severe ADC and in six of seven AIDS or asymptomatic human immunodeficiency virus-seropositive patients without clinical dementia, but at risk for ADC. The eye movement abnormalities detected included disturbances of both saccadic and smooth-pursuit function, and their severity correlated strongly with the severity of dementia. The abnormalities were qualitatively similar to those that occur in Alzheimer's disease but quantitatively less severe. Recording of eye movements may be a valuable, noninvasive technique for the early detection of neurologic dysfunction in asymptomatic patients who are seropositive for human immunodeficiency virus or in patients with AIDS, even prior to other clinical evidence of ADC. In particular, it may be of use in selecting high-risk patients requiring antiviral therapy and in monitoring the neurologic response to such treatment.     

Neuronal damage in the cerebral cortex of AIDS brains: a morphometric study

Summary Using stereological methods, two cerebral cortical areas from AIDS brains were investigated. Neuronal density, profile area of neurons, and perikaryon volume fraction were measured and compared to age-matched control brains. In the fronto-orbital cortex (area 11) of AIDS brains, a significant loss of neurons was seen. The perikaryon volume fraction was likewise decreased. The size of neurons did not differ between control and AIDS brains. In patients with clinical signs of progressive dementia and in brains with human immunodeficiency virus (HIV)-specific neuropathology (HIV-leukoencephalopathy and/or HIV-encephalitis) as compared to patients lacking these features, a small decrease in neuronal density was noted but this difference did not reach the level of statistical significance (P=0.16). In the superior parietal lobule (are 7) of AIDS brains, no loss of nerve cells was noted. AIDS patients with progressive dementia and brains with HIV-specific neuropathology showed no difference in neuronal densities as compared to those without such features. We conclude that the fronto-orbital cortex, in contrast to the parietal cortex, is mainly damaged in AIDS brains. Neuronal loss was not significantly correlated with development of dementing symptoms and of HIV-specific neuropathology.Supported by the Bundesministerium for Forschung und Technologie (FKZ: II-040-87) of the Federal Republic of Germany, and by the Fonds zur Förderung der Wissenschaftlichen Forschung (P8672-MED) of Austria