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PubMed1977

Slow infections of the central nervous system.

This review describes the recent advances in slow infections of the nervous system emphasizing the pathogenetic aspects of these diseases. A theoretical model for the pathogenesis of subacute sclerosing panencephalitis (SSPE) is proposed, illustrating the factors that may affect host response to the measles virus and allow it to persist and produce the panencephalitis. The isolation of an oncogenic virus from progressive multifocal leukoencephalopathy (PML) has implications in the consideration of a viral etiology for some brain tumors. The agent responsible for the transmissibility of kuru and Creutzfeldt-Jakob disease (CJD) remains uncharacterized despite recent interest in viroids and abnormalities in replication of cell membranes. The epidemiological data on multiple sclerosis suggests an exposure to an infectious agent at an early age of life modified by the host response. No specific agent has been consistently associated with multiple sclerosis. Amyotrophic lateral sclerosis (ALS), Parkinson's disease, Mollaret's meningitis and Behcet's disease are other examples where a virus is suspect but unproven. The ability of viruses to persist in the host for months to years has linked many chronic neurologic diseases to an infectious agent, enlarging the spectrum of disease caused by viruses.

Adolescent↗

PubMed1984

The neuropathology of acquired immune deficiency syndrome.

We reviewed the neuropathologic characteristics of 52 cases of acquired immune deficiency syndrome (AIDS) at autopsy. Histologically significant neuropathologic lesions were found in 38 cases. We believed that infection was the predominant pathologic process in 26 cases; occasionally, multiple infectious agents were present. This included Toxoplasma encephalitis (n = 16), fungal abscess (n = 1), tuberculous abscess (n = 1), progressive multifocal leukoencephalopathy (n = 2), cysticercosis (n = 1), and Escherichia coli meningoencephalitis (n = 1). Microglial nodules or perivascular inflammation suggested that encephalitis was the most likely cause in five cases. In two additional cases, a primary demyelinating process that was apparently related to cytomegalovirus was present. Vascular or hypoxic diseases were present in nine cases. The findings included intracerebral hemorrhage (n = 1), subarachnoid hemorrhage (n = 2), infarction (n = 2), diffuse hypoxic changes (n = 5), cerebral edema (n = 1), and rare thromboemboli with extravasation of RBCs (n = 1). One case of primary lymphoma was observed. The CNS lesions were the proximate cause of death in 15 patients. The CNS complications of AIDS are varied and often are the major manifestation of the syndrome.

Acquired Immunodeficiency Syndrome↗

PubMed1998

JC virus infection in cells from lymphoid tissue.

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease characterized by infection of oligodendrocytes by JC virus. The exact nature of the pathogenesis of PML is not known. The nature of the primary infection, the site of viral latency, and the route by which JCV enters the brain remain to be elucidated. Different laboratories have shown the presence of JCV in peripheral lymphocytes from immunosuppressed individuals, suggesting these cells as possible carriers of JCV to the brain. To examine this observation, we tested the susceptibility to JCV infection of cells from lymphoid organs, focusing our attention on CD34+ haematopoietic precursor cells and B lymphocytes. The results demonstrate that both these cell types are susceptible to JCV infection and, moreover, that JCV can infect only those cells that differentiate into lymphocytic lineage.

Antigens, CD34↗

PubMed1999

Rare AIDS-defining diseases in the Swiss HIV Cohort Study.

The objective of this study was to investigate the spectrum and frequency of rare AIDS-defining diseases in the Swiss HIV Cohort Study. AIDS-defining diseases contributing less than 1% to the absolute number of all recorded AIDS-defining diseases in at least one of five periods (1988-1990, 1991-1992, 1993-1994, 1995-1996, 1997) were defined as being rare. A total of 9110 HIV-infected subjects were included in this study. Over the entire 9-year period, the following rare diseases were diagnosed: progressive multifocal leukoencephalopathy (n = 138), disseminated cryptococcosis (n = 67), visceral herpes simplex disease (n = 66), primary cerebral lymphoma (n = 65), indeterminate cerebral lesion (n = 50), cryptococcal meningitis (n = 34), Mycobacterium kansasii disease (n = 32), recurrent Salmonella septicemia (n = 22), intestinal isosporiasis (n = 21), candidiasis of the trachea, bronchi and lungs (n = 19), toxoplasma retinitis (n = 16), disseminated toxoplasmosis (n = 8), invasive cervical carcinoma (n = 8), extrapulmonary Pneumocystis disease (n = 5), disseminated histoplasmosis (n = 1) and disseminated coccidioidomycosis (n = 1). Rare diseases accounted for 7.3% of all AIDS-defining diseases over the entire 9-year period. Physicians should be aware of the likelihood of a broad spectrum of AIDS-defining diseases in HIV-infected patients.

AIDS-Related Opportunistic Infections↗

PubMed1996

Detection of polyomaviral DNA in clinical samples from immunocompromised patients: correlation with clinical disease.

Clinical samples from immunocompromised patients were screened for polyomaviral sequences by nested polymerase chain reaction (PCR) to evaluate the association of these viral infections with progressive multifocal leukoencephalopathy (PML). JC virus (JCV) DNA was detected in 19 of 23 CSF samples and all four brain samples from patients with PML. Neither BK virus (BKV) nor simian virus 40 (SV40) DNA were detected in these samples. No evidence was found to support the hypothesis that polyomaviral DNA is present in the central nervous system of immunosuppressed patients without PML (CSF n = 67, brain n = 19). JCV DNA was not detected in any peripheral blood sample included in this study. JCV DNA was detected in urine from three of eight patients with PML, but was also amplified from three of 29 urine samples from patients without PML, JCV, and not SV40 or BKV, was associated with PML in this study.

BK Virus↗

PubMed1993

JC virus and multiple sclerosis: a refutation?

Polyomavirus JC (JCV) has been implicated in the etiology of multiple sclerosis (MS), because it causes progressive multifocal leukoencephalopathy (PML), a multifocal demyelinating disease with many microscopical similarities to MS. During childhood, the virus establishes a latent infection in the kidneys, which can be reactivated in immunocompromised patients. During reactivation, the virus is shed in the urine. The kidney is the only known site of latent infection and reactivation. Therefore, excretion of the virus in the urine of MS patients is to be expected, if reactivated JCV is involved in the etiology of MS. We studied urine samples of 53 patients with definitive MS and of 53 controls matched for age and sex. We found no evidence of active JCV infection in MS. The hypothesis of a polyomaviral etiology of MS is not supported by the results of this study.

Adult↗

PubMed1991

[Brain lesions in patients with acquired immunodeficiency syndrome].

During a period of 3 years 14 patients with AIDS and CNS focal lesions documented by CT scan were evaluated. All patients received empirical treatment against Toxoplasma. The aim of the study was to determine the prevalence of the different etiologies of the neurologic lesions as well as to evaluate the usefulness of routine cerebral biopsy before establishing empiric antitoxoplasma treatment in a population of AIDS patients with a high incidence of drug addiction. Eleven patients developed histologic and clinical criteria of cerebral toxoplasmosis, one patient presented progressive multifocal leukoencephalopathy, and in the remaining two patients the etiologic diagnosis could not be established. Only one patient presented multiple etiologic lesions and in no cases the presence of mycobacteria or fungi could be demonstrated in the cerebral tissue. The overall percentage of responses to the empiric antitoxoplasma treatment was 42%. This percentage increased to 54% if patients with coma were not included in the analysis. Cumulated mortality of the entire group was 78.5%. It is concluded: 1) the predominance of Toxoplasma gondii as a cause of cerebral lesions in our AIDS population; 2) the acceptable percentage of response to empiric antitoxoplasma treatment in non-comatose patients, and 3) the high overall mortality rate in these patients. It is therefore suggested that routine cerebral biopsies will not be justified as initial diagnostic approach in HIV positive patients with focal CNS lesions.

Acquired Immunodeficiency Syndrome↗

PubMed1983

Naturally occurring and passage-induced variation in the genome of JC virus.

We have examined both the naturally occurring and passage-induced variation in the genome of the human polyomavirus, JCV. JCV DNA was extracted directly from diseased brain tissue of ten cases of progressive multifocal leukoencephalopathy (PML) and the DNA population from any one case was homogeneous with respect to length and restriction endonuclease cleavage patterns. However, a comparison of cloned JCV DNAs revealed that the viral DNAs derived from different cases of PML were not identical. We identified a hypervariable region near the origin of DNA replication, and we demonstrated that there are two genetically distinguishable subtypes of the virus. After growth in vitro, the DNA from certain isolates of JCV became heterogeneous in size. Deletions of up to 12% of the genome occurred after as few a three low multiplicity passages in human glial cells. Most of the deletions mapped within the region presumed to code for T antigen. In addition, we examined the physical properties of JCV from brain and, as expected, they were typical of the polyomavirus genus.

Brain↗

PubMed2006

A granule cell neuron-associated JC virus variant has a unique deletion in the VP1 gene.

The human polyomavirus JC (JCV) typically infects glial cells and is the aetiological agent of progressive multifocal leukoencephalopathy (PML), which occurs in immunosuppressed individuals. The full-length sequence of a granule cell neuron-tropic JCV variant, JCV(GCN1), associated with lytic infection of granule cell neurons and cerebellar atrophy in a human immunodeficiency virus-infected patient with PML was determined and compared with the sequence of the JCV isolate from the classic PML lesions present in the hemispheric white matter of the same individual (JCV(HWM)). A unique deletion was found in the C terminus of the VP1 gene of JCV(GCN1), which encodes the major capsid protein, resulting in a frame shift and a total change of the C-terminal amino acid sequence of this protein. This deletion was not present in JCV(HWM), suggesting that this mutation may be instrumental in facilitating entry or replication of JCV into granule cell neurons.

AIDS-Related Opportunistic Infections↗

PubMed2006

Fatalities in natalizumab treatment--a 'no go' for leukocyte recirculation approaches?

Natalizumab (Tysabri), Biogen Idec/Elan) is a humanised neutralising antibody directed against alpha4 integrin expressed by leukocytes. Although it is an effective therapy for multiple sclerosis (MS), the serious adverse effect of progressive multifocal leukoencephalopathy (PML) resulted in its voluntary withdrawal from the market by Biogen Idec/Elan in February 2005. This has raised debates on whether PML was caused by blocking leukocyte trafficking-mediated immune suppression or by other effects through targeting alpha4 integrin per se. The authors propose that natalizumab-associated PML is a target-specific side effect predominantly due to the combination of: i) blocking leukocyte trafficking to peripheral organs resulting in reduced immune surveillance; ii) mobilisation of PML-causative JC virus-carrying bone marrow precursor cells and splenic marginal zone B cells; and iii) migration of these cells to sites of inflammation such as the brain. Therefore, combination of these effects is, so far, specific for the target alpha4 integrin and should not occur in general when interfering with other targets involved in leukocyte trafficking.

Antibodies, Monoclonal↗

PubMed2005

[Progressive multifocal leucoencephalopathy in AIDS patients. Hepatotoxicity of HAART in patients with hepatitis B or C].

Progressive multifocal leukoencephalopathy (PML) develops in 1-8% of patients with AIDS, for which it is a disease-defining condition. PML presents mainly in severely immunocompromised male intravenous drug users, having viral loads greater than log5 RNA copies/mL and CD4 populations lower than 150 cells/mm3. Death of AIDS patients with PML occurred after only 4 to 6 months before the introduction of highly active antiretroviral therapies (HAART), the only ones that have shown to prolong survival. Viral hepatitis is not the only liver condition affecting patients with AIDS, opportunistic infections and neoplasms, such as lymphoma and Kaposi's sarcoma, as well as biliary disease are also encountered but, fortunately, they are currently less frequent as a result of the new antiretroviral treatments. The risks of HAART hepatotoxicity in patients with hepatitis B or C have been studied by several groups.

Acquired Immunodeficiency Syndrome↗

PubMed1994

Phylogenetic comparison between archetypal and disease-associated JC virus isolates in Japan.

We examined the phylogenetical correlation between two types of JC virus (JCV) isolates, archetypes derived from the urine of nonimmunocompromised individuals and PML-types derived from the brain of patients with progressive multifocal leukoencephalopathy (PML) in Japan. A phylogenetic tree was constructed for eight JCV isolates, five PML-types obtained in this and previous studies and three representative archetypes, from DNA sequence data on the VP1 (major capsid protein) gene. The eight isolates were divided into two major groups, named subtypes MY and CY after the representative archetypal isolates. Four of five PML-type isolates belonged to subtype MY, and the other one to subtype CY. Isolates belonging to subtype MY were further divided into two groups; one group containing archetype MY and three PML-types and the other one containing archetype YI and a PML-type. These findings, together with those in our previous study that correlated various JCV isolates in the world provide evidence for the hypothesis that JCVs associated with PML may have been generated from archetypal JCVs persisting in the patients.

Base Sequence↗

PubMed1998

Management of intracerebral lesions in patients with HIV: a retrospective study with discussion of diagnostic problems.

A total of 95 patients who presented in 1994 and 1995 with focal brain lesions at a London HIV centre were studied retrospectively. Patients were allocated to "definite" or "presumed" diagnostic categories of toxoplasma encephalitis (TE), primary CNS lymphoma (PCNSL) or progressive multifocal leukoencephalopathy (PML), based on strict criteria. The number in each category was: TE, 20; PCNSL, 9; PML, 7; presumed TE, 12; presumed PCNSL, 8 and presumed PML, 17. There were 20 patients in whom a diagnosis could not be made, and there were three non-HIV diagnoses. Demographic data, features at presentation and routine CSF analysis were not discriminatory in making a diagnosis. Toxoplasma titres were a median of 1:256 in those with TE compared to 1:16 in all other groups (p < 0.001) and those with TE were less likely to be on toxoplasma prophylaxis compared to those with PCNSL (p < 0.002). Survival with TE (median of 446 days) was significantly longer than survival in all other groups. Survival with either confirmed or presumed PML was similar. The problems of diagnosis of focal brain lesions in HIV patients are discussed and a management flow chart for mass lesions is proposed.

AIDS-Related Opportunistic Infections↗

PubMed2002

The clinical profile of end-stage AIDS in the era of highly active antiretroviral therapy.

The purpose of this study was to describe the clinical profile of end-stage acquired immune deficiency syndrome (AIDS) since the advent of highly active antiretroviral therapy (HAART). A cross-sectional examination of human immunodeficiency virus (HIV)-infected patients who attended a public HIV outpatient clinic and died between 1996 and 2001 was conducted (n = 669). All clinical and demographic data were collected from the Centers for Disease Control (CDC) Adult Spectrum of Disease database. The prevalence of first-time acquisition of AIDS-defining conditions 12 months before death were evaluated. The prevalence of renal disease, hepatic disease and substance use were also evaluated. The majority of the patients were 35 years old or older, male, African American and HAART-experienced. The six AIDS-defining conditions with the highest percentages of first-time acquisition in the last 12 months of life were HIV dementia (91.8%), progressive multifocal leukoencephalopathy (PML) (91.7%), wasting (90.9%), Mycobacterium avium complex infection (MAC) (80.0%), lymphoma (78.6%), and cytomegalovirus infection (CMV) (78.1%). Forty-four percent of the patients were diagnosed with at least one of these six conditions 12 months before death. More than one third of the patients had renal or hepatic failure, injecting drug use (IDU) as the HIV risk factor, and history of substance use. AIDS-defining conditions continue to have an impact on mortality, especially the neurologic conditions and wasting. However, other conditions, such as renal and hepatic disease, are becoming important causes of mortality because the HIV-infected population now includes more drug users, and HIV-infected patients are surviving for longer periods. These results should help clinicians better time the discussion of end-stage options and improve the patient's quality of life.

AIDS Dementia Complex↗

PubMed1976

Comparison of JC and BK human papovaviruses with simian virus 40: DNA homology studies.

Studies were performed to ascertain the relationship of human papovavirus JC to BK virus and to simian virus 40 (SV40) by further restriction endonuclease analysis and by DNA-DNA competition hybridization on membrane filters. Form I DNA extracted from two new isolates from cases of progressive multifocal leukoencephalopathy of human papovaviruses that were JC-like in their antigenic properties were found to yield restriction endonuclease fragmentation patterns similar to those of prototypic JC virus DNA and different from those of BK or SV40. Form I DNA preparations of JC and BK viruses were found to be related to each other and to SV40 DNA to a similar extent, with JC and BK virus DNAs containing sequences homologous to both early and late regions of the SV40 genome. The relatedness in each comparison was less than 50%, and heterologous hybrids between either JC or BK and SV40 DNAs were found to be less stable than homologous SV40-SV40 hybrids in high concentrations of formamide, suggesting substantial mismatch within homologous regions, to the extent of 15 to 30%. The new JC-like isolates were also studied in competition hybridization reactions with SV40 DNA and yielded results similar to those obtained with JC virus.

BK Virus↗

PubMed1998

Measurement of viral sequences in cerebrospinal fluid of AIDS patients with cerebral white-matter lesions using polymerase chain reaction.

OBJECTIVES: To optimize the use of polymerase chain reaction (PCR) on cerebrospinal fluid (CSF) for the evaluation of central nervous system (CNS) white-matter lesions that along with clinical findings and magnetic resonance imaging (MRI) can allow a definite diagnosis to be made; also to evaluate treatment with zidovudine plus foscarnet. DESIGN AND METHODS: Fifteen AIDS patients with uncertain CNS white-matter lesions were identified. HIV-1 RNA, cytomegalovirus (CMV) and JC virus (JCV) DNA were measured in a total of 29 CSF samples. The results were correlated with clinical and MRI findings and treatment with zidovudine plus foscarnet was evaluated. RESULTS: Four and five out of 15 patients with CMV DNA > or = 1 : 625 and JCV DNA > or = 10(3) copies/microl detected in the CSF were diagnosed with CMV and progressive multifocal leukoencephalopathy (PML), respectively. Six patients who were CMV/JCV-negative with the highest levels of HIV RNA (median, 6.87 log10 copies/ml) in CSF were considered as having HIV-1 encephalitis. Neurological symptoms were non-supportive for diagnosis as was MRI in 11 out of 15 patients. Nine patients completed a 21-day course of zidovudine plus foscarnet. HIV RNA decreased irrespective of neurological diagnosis. All three HIV-1 encephalitis patients and two out of three patients with CMV leukoencephalopathy improved. In these two latter patients, relief of clinical symptoms coincided with decreased CMV DNA. JCV DNA remained unchanged and all three PML patients deteriorated. CONCLUSIONS: Measurement of CSF viral sequences supports the diagnosis of CNS white-matter lesions in AIDS patients. While effective therapy for PML remains elusive, treatment including zidovudine plus foscarnet may be a promising option for HIV-1 and CMV-related manifestations.

AIDS Dementia Complex↗

PubMed1987

[Neuropathologic findings in 13 deceased patients with acquired immunologic deficiency syndrome].

The neuropathological findings in 13 patients with the acquired immune deficiency syndrome (AIDS) and with AIDS related complex (ARC) are reported. Six patients presented with neurological symptoms, whereas autopsy revealed CNS involvement in nine cases. Four patients showed neither neurological nor neuropathological abnormalities. The most frequent neuropathological diagnoses were toxoplasma encephalitis (4 cases) and multiple or solitary cerebral necroses (3 cases). Long tract degeneration of the spinal cord was found in 2 cases. Cytomegalovirus infection, progressive multifocal leukoencephalopathy, primary lymphoma of the CNS, infiltration of the leptomeninges by plasmocytoma cells and a solitary metastasis of a bronchial carcinoma were diagnosed in one case each. Subacute leukoencephalitis, mentioned frequently in the literature, was not present in this material. In one case, however, status spongiosus and gliosis was found in the cortex and basal ganglia. As similar spongy changes can be seen in mice infected experimentally with retroviruses, a pathogenetic role of the human T-cell lymphotropic/leukaemia virus type III (HTLV-III) cannot be ruled out. Astrogliosis and hypertrophy of astrocytes were found in nine cases. Morphometrically, the number of astrocytes was significantly higher in AIDS patients than in control cases which were selected randomly on grounds of comparable age. Whether this finding bears some relationship with HTLV-III encephalopathy remains open to further investigation. Glial nodules were found in four cases; according to silver impregnation they were composed of microglial elements.

Acquired Immunodeficiency Syndrome↗

PubMed1992

The role of stereotactic biopsy in the management of HIV-related focal brain lesions.

The criteria for brain biopsy in patients with acquired immunodeficiency syndrome (AIDS) remain unclear and without universal acceptance. In order to shed more light on this issue, the authors reviewed the records of 25 AIDS patients with focal cerebral lesions who consecutively underwent stereotactic biopsy between November 1988 and October 1990. The most frequently occurring diagnoses were lymphoma (36%), progressive multifocal leukoencephalopathy (24%), and toxoplasmosis (8%). Patients whose central nervous system disease resulted in their initial presentation (approximately 40%) survived a median of 37 weeks, as opposed to 6 weeks for those who had previous AIDS-related infections. The proportion of biopsies of contrast-enhancing lesions that were diagnostic and thereby contributed to the patients' therapeutic management was 87.5%. On the other hand, only 67% of the biopsies of nonenhancing lesions were diagnostic, and none of these lesions were treatable. All of the lymphoma patients had had AIDS for some time and, despite a reasonable preoperative Karnofsky score and postoperative radiation therapy, their median survival was only 6 weeks; however, biopsy was critical to their therapeutic management. Early brain biopsy, rather than empiric antitoxoplasmosis therapy, appears indicated for aggressive therapy of contrast-enhancing lesions in patients who have had previous manifestations of AIDS. The role for biopsy of nonenhancing lesions is less clear, but it may provide prognostic information.

AIDS Dementia Complex↗