996 resultados para JC virus


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Introduction: Several presentations of neurologic complications caused by JC virus (JCV) in human immunodeficiency virus (HIV)-infected patients have been described and need to be distinguished from the "classic" form of progressive multifocal leukoencephalopathy (PML). The objectives of this study were: 1) to describe the spectrum and frequency of presentations of JCV-associated central nervous system (CNS) diseases; 2) identify factors associated with in-hospital mortality of patients with JCV-associated CNS disease; and 3) to estimate the overall mortality of this population. Material and methods: This was a retrospective study of HIV-infected patients admitted consecutively for JCV-associated CNS diseases in a referral teaching center in Sao Paulo, Brazil, from 2002 to 2007. All patients with laboratory confirmed JCV-associated CNS diseases were included using the following criteria: compatible clinical and radiological features associated with the presence of JCV DNA in the cerebrospinal fluid. JCV-associated CNS diseases were classified as follows: 1) classic PML; 2) inflammatory PML; and 3) JC virus granule cell neuronopathy (GCN). Results: We included 47 cases. JCV-associated CNS diseases were classified as follows: 1) classic PML: 42 (89%); 2) inflammatory PML: three (6%); and 3) JC virus GCN: four (9%). Nosocomial pneumonia (p = 0.003), previous diagnosis of HIV infection (p = 0.03), and imaging showing cerebellar and/or brainstem involvement (p = 0.02) were associated with in-hospital mortality. Overall mortality during hospitalization was 34%. Conclusions: Novel presentations of JCV-associated CNS diseases were observed in our setting; nosocomial pneumonia, previous diagnosis of HIV infection, and cerebellar and/or brainstem involvement were associated with in-hospital mortality; and overall mortality was high. (C) 2012 Elsevier Editora Ltda. All rights reserved.

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Progressive multifocal leukoencephalopathy (PML) is a frequently fatal disease caused by uncontrolled polyomavirus JC (JCV) in severely immunodeficient patients. We investigated the JCV-specific cellular and humoral immunity in the Swiss HIV Cohort Study. We identified PML cases (n = 29), as well as three matched controls per case (n = 87), with prospectively cryopreserved peripheral blood mononuclear cells and plasma at diagnosis. Nested controls were matched according to age, gender, CD4(+) T-cell count, and decline. Survivors (n = 18) were defined as being alive for >1 year after diagnosis. Using gamma interferon enzyme-linked immunospot assays, we found that JCV-specific T-cell responses were lower in nonsurvivors than in their matched controls (P = 0.08), which was highly significant for laboratory- and histologically confirmed PML cases (P = 0.004). No difference was found between PML survivors and controls or for cytomegalovirus-specific T-cell responses. PML survivors showed significant increases in JCV-specific T cells (P = 0.04) and immunoglobulin G (IgG) responses (P = 0.005). IgG responses in survivors were positively correlated with CD4(+) T-cell counts (P = 0.049) and negatively with human immunodeficiency virus RNA loads (P = 0.03). We conclude that PML nonsurvivors had selectively impaired JCV-specific T-cell responses compared to CD4(+) T-cell-matched controls and failed to mount JCV-specific antibody responses. JCV-specific T-cell and IgG responses may serve as prognostic markers for patients at risk.

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Although polyomavirus JC (JCV) is the proven pathogen of progressive multifocal leukoencephalopathy, the fatal demyelinating disease, this virus is ubiquitous as a usually harmless symbiote among human beings. JCV propagates in the adult kidney and excretes its progeny in urine, from which JCV DNA can readily be recovered. The main mode of transmission of JCV is from parents to children through long cohabitation. In this study, we collected a substantial number of urine samples from native inhabitants of 34 countries in Europe, Africa, and Asia. A 610-bp segment of JCV DNA was amplified from each urine sample, and its DNA sequence was determined. A worldwide phylogenetic tree subsequently constructed revealed the presence of nine subtypes including minor ones. Five subtypes (EU, Af2, B1, SC, and CY) occupied rather large territories that overlapped with each other at their boundaries. The entire Europe, northern Africa, and western Asia were the domain of EU, whereas the domain of Af2 included nearly all of Africa and southwestern Asia all the way to the northeastern edge of India. Partially overlapping domains in Asia were occupied by subtypes B1, SC, and CY. Of particular interest was the recovery of JCV subtypes in a pocket or pockets that were separated by great geographic distances from the main domains of those subtypes. Certain of these pockets can readily be explained by recent migrations of human populations carrying these subtypes. Overall, it appears that JCV genotyping promises to reveal previously unknown human migration routes: ancient as well as recent.

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The human polyomavirus JC (JCV) causes the central nervous system demyelinating disease progressive multifocal leukoencephalopathy. Previously, we showed that 40% of Caucasians in the United States excrete JCV in the urine as detected by PCR. We have now studied 68 Navaho from New Mexico, 25 Flathead from Montana, and 29 Chamorro from Guam. By using PCR amplification of a fragment of the VP1 gene, JCV DNA was detected in the urine of 45 (66%) Navaho, 14 (56%) Flathead, and 20 (69%) Chamorro. Genotyping of viral DNAs in these cohorts by cycle sequencing showed predominantly type 2 (Asian), rather than type 1 (European). Type 1 is the major type in the United States and Hungary. Type 2 can be further subdivided into 2A, 2B, and 2C. Type 2A is found in China and Japan. Type 2B is a subtype related to the East Asian type, and is now found in Europe and the United States. The large majority (56–89%) of strains excreted by Native Americans and Pacific Islanders were the type 2A subtype, consistent with the origin of these strains in Asia. These findings indicate that JCV infection of Native Americans predates contact with Europeans, and likely predates migration of Amerind ancestors across the Bering land bridge around 12,000–30,000 years ago. If JCV had already differentiated into stable modern genotypes and subtypes prior to first settlement, the origin of JCV in humans may date from 50,000 to 100,000 years ago or more. We conclude that JCV may have coevolved with the human species, and that it provides a convenient marker for human migrations in both prehistoric and modern times.

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JC virus is activated to replicate in glial cells of many AIDS patients with neurological disorders. In human glial cells, the human immunodeficiency virus 1 (HIV-1) Tat protein activates the major late promoter of JC virus through a Tat-responsive DNA element, termed upTAR, which is a recognition site for cellular Purα, a sequence-specific single-stranded DNA binding protein implicated in cell cycle control of DNA replication and transcription. Tat interacts with two leucine-rich repeats in Purα to form a complex that can be immunoprecipitated from cell extracts. Tat enhances the ability of purified glutathione S-transferase-Purα (GST-Purα) to bind the upTAR element. Tat acts synergistically with Purα, in a cell-cycle-dependent manner, to activate transcription at an upTAR element placed upstream of a heterologous promoter. Since Purα is ubiquitously expressed in human cells and since PUR elements are located near many promoters and origins of replication, the Tat-Purα interaction may be implicated in effects of HIV-1 throughout the full range of HIV-1-infected cells.

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We describe molecular and clinical findings in an immunocompetent patient with an oligoastrocytoma and the concomitant presence of the human papovavirus, JC virus (JCV), which is the etiologic agent of the subacute, debilitating demyelinating disease, progressive multifocal leukoencephalopathy. Histologic review revealed a glial neoplasm consisting primarily of a moderately cellular oligodendroglioma with distinct areas of a fibrillary astrocytoma. Immunohistochemical analysis revealed nuclear staining of tumor cells with antibodies against the viral oncoprotein [tumor antigen (T antigen)], the proliferation marker (Ki67), and the cellular proliferation regulator (p53). Using primers specific to the JCV control region, PCR yielded amplified DNA that was identical to the control region of the Mad-4 strain of the virus. PCR analysis demonstrated the presence of the genome for the viral oncoprotein, T antigen, and results from primer extension studies revealed synthesis of the viral early RNA for T antigen in the tumor tissues. The presence of viral T antigen in the tumor tissue was further demonstrated by immunoblot assay. To our knowledge, this is the first report of the presence of JCV DNA, RNA, and T antigen in tissue in which viral T antigen is localized to tumor cell nuclei and suggests the possible association of JCV with some glial neoplasms.

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Background: JC virus (JCV), the causative agent of progressive multifocal leukoencephalopathy (PML), is classified in 8 different genotypes. Previous reports have suggested a positive association between specific genotypes and PML. Objective: To compare genotypes and adaptive mutations of JCV strains from Brazilian AIDS patients with and without PML. Study design: The VP1 region of JCV was amplified by polymerase chain reaction from cerebrospinal fluid samples from 51 patients with PML and from urine samples of 47 patients with AIDS without central nervous system disease. Genotyping was done by phylogenetic analysis. Amino acid replacement and selection pressures were also investigated. Results: JCV genotype frequency distributions showed that genotypes 2 (32.7%), 1 (26.5%) and 3 (23.5%) were the most prevalent. Genotype 1 had a positive association (p < 0.0001) and genotype 3 showed an inverse association (p < 0.001) with PML. A previously undescribed point mutation at residue 91 (L/I or L/V) and (L/P), non-genotype-associated, was found in 5/49 (10.2%) and 2/47 (4.3%) JCV sequences from PML and non-PML patients, respectively. This mutation was under positive selection only in PML patients. A previously described substitution of T-A in position 128 showed a significant difference between PML and non-PML cases (70% versus 16%, respectively, p < 0.0005). Conclusion: In Brazilian patients with AIDS, JCV genotype 1 showed a strong association with PML (p < 0.0001) and JCV genotype 3 showed an inverse association with PML. The possible association of aminoacids substitution in residues 91 and 128 with PML in patients with AIDS must be further investigated. (C) 2010 Elsevier B.V. All rights reserved.

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O presente trabalho investigou a ocorrência de infecção pelos poliomavírus JCV e BKV na população de pacientes com doença renal crônica, no Estado do Acre e em um grupo controle de indivíduos sem doença renal. Foram examinadas 100 amostras de urina do grupo de Pacientes e 99 amostras de urina do grupo Controle. Após a extração do DNA, a PCR foi usada para a amplificação de 173pb do gene que codifica o antígeno-T de ambos os vírus. A diferenciação entre as infecções por JCV e por BKV foi realizada por meio da digestão enzimática do produto amplificado, usando-se endonuclease de restrição. Esse estudo não identificou a presença do BKV nas amostras de urina do grupo de Pacientes e do grupo Controle. O JCV foi identificado em 11,1% (11/99) dos indivíduos do grupo Controle e em 4% (4/100) dos indivíduos do grupo de Pacientes. Foi encontrada diferença estatisticamente significante entre os grupos de Pacientes e Controle quanto à média de Uréia (p < 0,001), onde a média no grupo de Pacientes foi significantemente maior do que a média no grupo Controle. Estes resultados sugerem que os elevados níveis de uréia excretada na urina, a baixa celularidade urinária, a diminuição do “washout” (limpeza) da bexiga e o tempo para a análise das amostras, justifiquem a baixa prevalência de infecção encontrada no grupo de pacientes renais crônicos; pois esses fatores podem diminuir a quantidade de vírus na urina ou podem atuar como inibidores da PCR. Esse estudo sugere a necessidade de aumentar a sensibilidade dos testes para a identificação desses vírus.

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This study evaluated the relative occurrences of BK virus (BKV) and JC virus (JCV) infections in patients with chronic kidney disease (CKD). Urine samples were analysed from CKD patients and from 99 patients without CKD as a control. A total of 100 urine samples were analysed from the experimental (CKD patients) group and 99 from the control group. Following DNA extraction, polymerase chain reaction (PCR) was used to amplify a 173 bp region of the gene encoding the T antigen of the BKV and JCV. JCV and BKV infections were differentiated based on the enzymatic digestion of the amplified products using BamHI endonuclease. The results indicated that none of the patients in either group was infected with the BKV, whereas 11.1% (11/99) of the control group subjects and 4% (4/100) of the kidney patients were infected with the JCV. High levels of urea in the excreted urine, low urinary cellularity, reduced bladder washout and a delay in analysing the samples may have contributed to the low prevalence of infection. The results indicate that there is a need to increase the sensitivity of assays used to detect viruses in patients with CDK, especially given that polyomavirus infections, especially BKV, can lead to a loss of kidney function following transplantation.

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The human poliomavirus is the etiologic agente of Progressive multifocal leukoencephalopathy (PML), a disease characterized by focal lesions not expansives of the central nervous system that develops in imunocompromissed patients, specially people with aids. The main aim of the study was to evalute the prevalence of the JCV excretion in urine samples of patients with aids, without PML, to compare two JCV DNA detection techniques through of two diferents genomic regions and to evaluate the genotypic characterization of the positive samples. A total of 75 samples were colected in the Instituto de Infectologia Emílio Ribas, in Sao Paulo, Brazil, between may and november, 2009. To detect the JC virus it was made the DNA extraction and then the polimerase chain reaction (PCR). Firstly a fragment of 215 bp was amplified, which corresponds to the codifying gene of the strutural protein of de JC vírus capsid VP1. All the samples were later submitted to another PCR that uses a pair of primers complementaries to the early region of the JCV (T antigen) amplifying a fragment of 173 bp. Followed by the digestion of the amplified product with the restriction enzime BamH1, resulting in two smaller fragments (120 bp and 53 bp). The JC vírus was detected in 53 samples, for both techniques (70,7% for VP1 PCR, and the restriction enzime BamH1), 34/46 were men (73,9%) and 19/29 were women (65,5%). The JCV excretion was higher in individuals that were over 46 years old. Regarding the seven genotypes described in the literature, the ones that were more prevalent among the JC positive patients were 3B and 3A with 10 samples each (21,0%), the 2B with 9 samples (19,0%) and genotype 6, with six samples (13,0%). As in the brown patients as the white ones, the most prevalent genotype was 3B. In the present study it was observed a high prevalence of JCV DNA (70,7%) and the genotype 3 (43,0%)... (Complete abstract click electronic access below)

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OBJECTIVE: To evaluate the prevalence of the urinary excretion of BKV and JCV in HIV-infected patients without neurological symptoms. METHODS: Urine samples from HIV-infected patients without neurological symptoms were tested for JC virus and BK virus by PCR. Samples were screened for the presence of polyomavirus with sets of primers complementary to the early region of JCV and BKV genome (AgT). The presence of JC virus or BK virus were confirmed by two other PCR assays using sets of primers complementary to the VP1 gene of each virus. Analysis of the data was performed by the Kruskal-Wallis test for numerical data and Pearson or Yates for categorical variables. RESULTS: A total of 75 patients were included in the study. The overall prevalence of polyomavirus DNA urinary shedding was 67/75 (89.3%). Only BKV DNA was detected in 14/75 (18.7%) urine samples, and only JCV DNA was detected in 11/75 (14.7%) samples. Both BKV and JCV DNA were present in 42/75 (56.0%) samples. CONCLUSION: In this study we found high rates of excretion of JCV, BKV, and simultaneous excretion in HIV+ patients. Also these results differ from the others available on the literature.

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Though difficult, the study of gene-environment interactions in multifactorial diseases is crucial for interpreting the relevance of non-heritable factors and prevents from overlooking genetic associations with small but measurable effects. We propose a "candidate interactome" (i.e. a group of genes whose products are known to physically interact with environmental factors that may be relevant for disease pathogenesis) analysis of genome-wide association data in multiple sclerosis. We looked for statistical enrichment of associations among interactomes that, at the current state of knowledge, may be representative of gene-environment interactions of potential, uncertain or unlikely relevance for multiple sclerosis pathogenesis: Epstein-Barr virus, human immunodeficiency virus, hepatitis B virus, hepatitis C virus, cytomegalovirus, HHV8-Kaposi sarcoma, H1N1-influenza, JC virus, human innate immunity interactome for type I interferon, autoimmune regulator, vitamin D receptor, aryl hydrocarbon receptor and a panel of proteins targeted by 70 innate immune-modulating viral open reading frames from 30 viral species. Interactomes were either obtained from the literature or were manually curated. The P values of all single nucleotide polymorphism mapping to a given interactome were obtained from the last genome-wide association study of the International Multiple Sclerosis Genetics Consortium & the Wellcome Trust Case Control Consortium, 2. The interaction between genotype and Epstein Barr virus emerges as relevant for multiple sclerosis etiology. However, in line with recent data on the coexistence of common and unique strategies used by viruses to perturb the human molecular system, also other viruses have a similar potential, though probably less relevant in epidemiological terms. © 2013 Mechelli et al.

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Viral infections can be a major thread for the central nervous system (CNS), therefore, the immune system must be able to mount a highly proportionate immune response, not too weak, which would allow the virus to proliferate, but not too strong either, to avoid collateral damages. Here, we aim at reviewing the immunological mechanisms involved in the host defense in viral CNS infections. First, we review the specificities of the innate as well as the adaptive immune responses in the CNS, using several examples of various viral encephalitis. Then, we focus on three different modes of interactions between viruses and immune responses, namely human Herpes virus-1 encephalitis with the defect in innate immune response which favors this disease; JC virus-caused progressive multifocal leukoencephalopathy and the crucial role of adaptive immune response in this example; and finally, HIV infection with the accompanying low grade chronic inflammation in the CNS in some patients, which may be an explanation for the presence of cognitive disorders, even in some well-treated HIV-infected patients. We also emphasize that, although the immune response is generally associated with viral replication control and limited cellular death, an exaggerated inflammatory reaction can lead to tissue damage and can be detrimental for the host, a feature of the immune reconstitution inflammatory syndrome (IRIS). We will briefly address the indication of steroids in this situation.

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Las infecciones del sistema nervioso son importantes fuentes de morbilidad y mortalidad en el mundo, debido a diferentes factores como son el amplio uso de antibióticos que aunque contribuyen con éxito al manejo de infecciones, pero el mal uso por automedicación o tratamientos incompletos favorecen la emergencia de organismos resistentes y la existencia de “mimos infecciosos” que incluyen el síndrome de reconstitución inflamatoria (IRIS). Adicionalmente el crecimiento de las poblaciones inmunocomprometidas por el síndrome de inmunodeficiencia adquirida (SIDA) y por tratamientos agresivos para trasplante sólido o hematopoyético han mejorado la sobrevida de diferentes tipos de malignidades y alteraciones reumatológicas pero son poblaciones que tienen más susceptibilidad a contraer infecciones y encefalitis mediadas inmunológicamente, como son la encefalomielitis diseminada aguda (ADEM) o la encefalitis contra el receptor de N-metil-D aspartato (NMDA).

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An 80-year-old man with no history of an immune-compromising disorder was diagnosed with progressive multifocal leukoencephalopathy (PML). He presented with dysphagia and left-sided weakness; magnetic resonance imaging demonstrated marked signal abnormality in the subcortical white matter of the left frontal lobe and in the posterior limb of the right internal capsule. Polymerase chain reaction (PCR) analysis of the cerebrospinal fluid (CSF) was negative for John Cunningham (JC) virus. On brain biopsy, foamy macrophages infiltrating the white matter were identified, staining positive for anti-simian virus 40 antibodies. Postoperatively, PCR for JC viral DNA in the CSF was positive, establishing the diagnosis of PML. Extensive investigation for an occult immunocompromising disorder was negative. The patient's neurologic deficits rapidly increased throughout his hospital stay, and he died 3.5 months after his diagnosis.