Amplification of JC virus regulatory DNA sequences from cerebrospinal fluid: diagnostic value for progressive multifocal leukoencephalopathy

Progressive Multifocal Leukoencephalopathy in a Patient With Classic Hodgkin's Lymphoma Post-Bone Marrow Transplant: A Case Report

A 29-year-old male patient underwent an autologous bone marrow transplant. He was initially diagnosed with Hodgkin's lymphoma and treated with 12 cycles of chemotherapy. Three months later, he presented with intermittent fever and underwent an MRI scan and a brain biopsy. Eventually, he was diagnosed with progressive multifocal leukoencephalopathy. For effective treatment and a plan of action, such cases necessitate multidisciplinary board meetings with input from experts in surgery, pathology, cancer, and infectious diseases.

Progressive multifocal leukoencephalopathy with mild clinical conditions and detection of archetype-like JC virus in cerebrospinal fluid

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system with a poor prognosis and is primarily caused by JC virus (JCV) with a mutation called prototype. We encountered a case of PML with moderate progression and analyzed the mutational patterns of JCV in the cerebrospinal fluid (CSF). A 19-year-old Japanese woman with mild neurological symptoms was diagnosed with combined immunodeficiency following pneumocystis pneumonia. Brain magnetic resonance imaging scan showed multiple brain lesions, and real-time polymerase chain reaction testing detected JCV in the CSF, leading to the diagnosis of PML. The disease course of PML was stable after administration of mefloquine and mirtazapine with immunoglobulin replacement therapy. In the JCV genome cloned from the patient CSF, DNA sequences of the gene encoding the capsid protein (VP1) and the non-coding control region exhibited small mutations. However, they were quite similar to those of the archetype JCV, which persists asymptomatically in healthy individuals. These findings provide insight into the mutational characteristics of JCV in PML with mild symptoms and progression.

Database and Statistical Analyses of Transcription Factor Binding Sites in the Non-Coding Control Region of JC Virus

JC virus (JCV), as an archetype, establishes a lifelong latent or persistent infection in many healthy individuals. In immunocompromised patients, prototype JCV with variable mutations in the non-coding control region (NCCR) causes progressive multifocal leukoencephalopathy (PML), a severe demyelinating disease. This study was conducted to create a database of NCCR sequences annotated with transcription factor binding sites (TFBSs) and statistically analyze the mutational pattern of the JCV NCCR. JCV NCCRs were extracted from >1000 sequences registered in GenBank, and TFBSs within each NCCR were identified by computer simulation, followed by examination of their prevalence, multiplicity, and location by statistical analyses. In the NCCRs of the prototype JCV, the limited types of TFBSs, which are mainly present in regions D through F of archetype JCV, were significantly reduced. By contrast, modeling count data revealed that several TFBSs located in regions C and E tended to overlap in the prototype NCCRs. Based on data from the BioGPS database, genes encoding transcription factors that bind to these TFBSs were expressed not only in the brain but also in the peripheral sites. The database and NCCR patterns obtained in this study could be a suitable platform for analyzing JCV mutations and pathogenicity.

Human iPS cell-derived astrocytes support efficient replication of progressive multifocal leukoencephalopathy-type JC polyomavirus

JC polyomavirus (JCPyV) causes progressive multifocal leukoencephalopathy (PML), a demyelinating disease of the central nervous system, in immunocompromised patients. Although PML used to be rare, recently the incidence of PML has risen due to an increase in immunosuppressive therapy. An in vitro JCPyV infection system could be used for anti-drug screening and investigation of tropism changes, but study of JCPyV in vitro has been limited due to the difficulty of efficiently propagating the virus in cultured cells. PML-type JCPyV efficiently propagates in primary human fetal and progenitor cell-derived astrocytes, but the preparation of cells from human fetuses is associated with severe ethical problems. In this study, human iPS cell-derived astrocytes were exposed to PML-type JCPyV. Infection, replication, and VP1 and T antigens of JCPyV were detected and confirmed in this culture. The non-coding control region (NCCR) of M1-IMRb was conserved in infected cells without point mutations. In addition, PML-type JCPyV genomic DNA in infected cells was detected as a single band of approximately 5.1 kbp, with no deletions. This is the first demonstration that human iPS cell-derived astrocytes efficiently support replication of PML-type JCPyV without production of defective interfering particles. These findings indicated that a culture system using human iPS cell-derived astrocyte would be useful for studies of PML, especially for screening anti-JCPyV drugs.

A loop-mediated isothermal amplification assay for the detection and quantification of JC polyomavirus in cerebrospinal fluid: a diagnostic and clinical management tool and technique for progressive multifocal leukoencephalopathy

Background

JC polyomavirus (JCV) is the causative agent of progressive multifocal leukoencephalopathy (PML), a demyelinating disease of the central nervous system in immunosuppressed patients. PML usually has a poor prognosis. Detection and quantification of the JCV genome in cerebrospinal fluid (CSF) is an efficacious tool for the diagnosis and management of PML, for which proper therapeutic interventions are required.

Methods

A loop-mediated isothermal amplification (LAMP) assay was applied for the quantitative detection of JCV. The LAMP assay was evaluated for the efficacy in diagnosis of PML in comparison with the TaqMan-based quantitative real-time PCR (qPCR) assay using 153 CSF specimens collected from patients with suspected PML.

Results

The LAMP assay showed no cross-reactivity against other polyomavirus plasmids, viral DNA, and viral RNA, which causes encephalitis, and detected 1 copy of the standard DNA per reaction. Among 50 qPCR-positives, 42 specimens (containing JCV genome ranged from 3.2 × 10⁰ to 3.2 × 10⁶ copies/reaction) showed positive reactions and 8 specimens (containing 0.9 to 19.9 copies/reaction) showed negative in the LAMP assay. Furthermore, 3 of 103 qPCR-negative specimens showed positive reactions in the LAMP assay. The sensitivity, specificity, positive predictive value, and negative predictive values of the LAMP assay were 84% (42/50), 97% (100/103), 93% (42/45), and 93% (100/108), respectively. The kappa statistic was 0.83. The JCV loads determined by the LAMP assay showed a strong positive correlation with those determined by the qPCR assay for 33 specimens with copy numbers of ≥1 copies/reaction (r = 0.89). Additionally, the LAMP assay could monitor the JCV genome copy number in CSF for sequential samples equivalently to qPCR assay.

Conclusions

The newly developed LAMP assay is highly specific against JCV and detect the JCV genome in the sample DNA containing 20 or more copies of JCV genome per reaction with 100% sensitivity (n = 29), which corresponds to ≥3 × 10³ copies/mL of CSF. The LAMP assay is useful for the diagnosis and offers valuable information for the evaluation and management of PML in the clinical setting.

Analysis of variability of urinary excreted JC virus strains in patients infected with HIV and healthy donors

In immunocompromised individuals, especially in patients with T cell immunodeficiency, reactivation of JCPyV can cause serious life-threatening diseases. Nowadays, HIV infection is one of the most important factor for reactivation of JCPyV and the development of of the progressive multifocal leukoencephalopathy (PML). Mutations in the outer loops of the VP1 region can lead to the selection of the viral variants with changed tropism and increased pathological potential. The aims of this study were to determine sequence variation and amino acid changes within VP1 loops and the structure of non-coding control region (NCCR) of urinary excreted JCPyV isolates among HIV-infected patients and healthy donors. Single urine samples from 114 HIV-infected patients and 120 healthy donors were collected. PCR was performed for amplification of VP1 and NCCR. Amplified fragments were directly sequenced and analyzed by using bioinformatics tools. Nucleotide substitutions were detected within DE and EF loops and in the β-sheets of both studied groups. In HIV-infected patients group, 70% of mutations were detected within receptor domains. Among healthy donors, one mutation was identified within β-sheets while the remaining were located within receptor domains. The most prevalent mutation was L157V in both groups. Analysis of NCCR revealed that all isolates had archetype structure with some minor changes. Since single point mutations at specific place within outer loop of VP1 region can cause formation of variants with changed receptor specificity, identification of these mutations in HIV-infected patients can help to single out those with higher risk for development of polyomavirus-associated diseases.

Deep-Sequence Identification and Role in Virus Replication of a JC Virus Quasispecies in Patients with Progressive Multifocal Leukoencephalopathy

JC virus (JCV) is a DNA virus causing progressive multifocal leukoencephalopathy (PML) in immunodeficient patients. In the present study, 22 genetic quasispecies with more than 1.5% variant frequency were detected in JCV genomes from six clinical samples of PML by next-generation sequencing. A mutation from A to C at nucleotide (nt) 3495 in JCV Mad1 resulting in a V-to-G amino acid substitution at amino acid (aa) position 392 of the large T antigen (TAg) was identified in all six cases of PML at 3% to 19% variant frequencies. Transfection of JCV Mad1 DNA possessing the V392G substitution in TAg into IMR-32 and human embryonic kidney 293 (HEK293) cells resulted in dramatically decreased production of JCV-encoded proteins. The virus DNA copy number was also reduced in supernatants of the mutant virus-transfected cells. Transfection of the IMR-32 and HEK293 cells with a virus genome containing a revertant mutation recovered viral production and protein expression. Cotransfection with equal amounts of wild-type genome and mutated JCV genome did not reduce the expression of viral proteins or viral replication, suggesting that the mutation did not have any dominant-negative function. Finally, immunohistochemistry demonstrated that TAg was expressed in all six pathological samples in which the quasispecies were detected. In conclusion, the V392G amino acid substitution in TAg identified frequently in PML lesions has a function in suppressing JCV replication, but the frequency of the mutation was restricted and its role in PML lesions was limited.

IMPORTANCE

DNA viruses generally have lower mutation frequency than RNA viruses, and the detection of quasispecies in JCV has rarely been reported. In the present study, a next-generation sequencer identified a JCV quasispecies with an amino acid substitution in the T antigen in patients with PML. In vitro studies showed that the mutation strongly repressed the expression of JC viral proteins and reduced the viral replication. However, because the frequency of the mutation was low in each case, the total expression of virus proteins was sustained in vivo. Thus, JC virus replicates in PML lesions in the presence of a mutant virus which is able to repress virus replication.

High-resolution melting analysis for mutation scanning in the non-coding control region of JC polyomavirus from patients with progressive multifocal leukoencephalopathy

JC polyomavirus (JCV) is the causative agent of progressive multifocal leukoencephalopathy (PML), a fatal demyelinating disease. JCV isolates from PML patients have hypervariable mutations in the noncoding control region (NCCR) of the viral genome. Although nucleotide sequencing analysis of NCCR mutation is useful for the confirmation of PML diagnosis and basic studies examining JCV variants, it is often labor-intensive, time-consuming, and expensive. This study was conducted to evaluate the feasibility of a high-resolution melting (HRM) analysis technique for the rapid and low-cost scanning of NCCR mutations. The real-time PCR-HRM assay was developed with a pair of primers targeting the NCCR, and mutational patterns of NCCRs were compared using sequence-confirmed JCV DNA clones and CSF DNAs from PML patients. The NCCR patterns of DNA clones of the archetype JCV and PML-type variants could be differentiated by PCR-HRM. The mutational patterns of the rearranged NCCR clones were similar to those of JCV variants in the original CSF specimens as judged by nested PCR-HRM using pre-amplified targets. In addition, nested PCR-HRM could distinguish NCCR mutations in the JCV DNAs from each specimen at the patient level. These results indicate that the HRM-based assay affords a valuable technique for PML diagnosis and a versatile tool for the rapid scanning of NCCR mutations.

Sequential changes in the non-coding control region sequences of JC polyomaviruses from the cerebrospinal fluid of patients with progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is caused by JC polyomavirus (JCV) infection in the brain. JCV isolates from PML patients have variable mutations in the non-coding control region (NCCR) of the genome. This study was conducted to examine sequential changes in NCCR patterns of JCV isolates obtained from the cerebrospinal fluid (CSF) of PML patients. CSF specimens were collected from PML patients at different time points, the NCCR sequences were determined, and their compositions were assessed by computer-based analysis. In patients showing a marked increase in JCV load, the most frequent NCCR sequences in the follow-up specimens were different from those in the initial samples. In contrast, the dominant NCCRs in the CSF remained unaltered during the follow-up of individuals in whom the viral load decreased after therapeutic intervention. These data demonstrate that the majority of JCV variants emerge with the progression of PML and that these changes are suppressed when the viral load is decreased.

Management and outcome of CSF-JC virus PCR-negative PML in a natalizumab-treated patient with MS

OBJECTIVE

To describe the diagnosis and management of a 49-year-old woman with multiple sclerosis (MS) developing a progressive hemiparesis and expanding MRI lesion suspicious of progressive multifocal leukoencephalopathy (PML) 19 months after starting natalizumab.

RESULTS

Polyomavirus JC (JCV)-specific qPCR in CSF was repeatedly negative, but JCV-specific antibodies indicated intrathecal production. Brain biopsy tissue taken 17 weeks after natalizumab discontinuation and plasmapheresis was positive for JCV DNA with characteristic rearrangements of the noncoding control region, but histology and immunohistochemistry were not informative except for pathologic features compatible with immune reconstitution inflammatory syndrome. A total of 22 months later, the clinical status had returned close to baseline level paralleled by marked improvement of neuroradiologic abnormalities.

CONCLUSIONS

This case illustrates diagnostic challenges in the context of incomplete suppression of immune surveillance and the potential of recovery of PML associated with efficient immune function restitution.

JC virus variant associated with cerebellar atrophy in a patient with AIDS

The human polyomavirus JC virus (JCV) is the agent of progressive multifocal leukoencephalopathy (PML). It has also recently been involved in cerebellar atrophy. Factors involved in this entity are elusive. We present a case of a human immunodeficiency virus (HIV)-infected patient with PML and cerebellar atrophy. In addition to a compartmentalization of JCV strains between urine, cerebrospinal fluid, and cerebellum, specific rearrangements in the JCV regulatory region were observed in the cerebellum, resulting in alterations of transcription factor binding sites. Our data underline the importance of searching for JCV in HIV-infected patients with cerebellar disorders and suggest that mutations in the regulatory region may be involved in cerebellar degeneration.

Rearranged JC virus noncoding control regions found in progressive multifocal leukoencephalopathy patient samples increase virus early gene expression and replication rate

Polyomavirus JC (JCV) infects ∼ 60% of the general population, followed by asymptomatic urinary shedding in ∼ 20%. In patients with pronounced immunodeficiency, including HIV/AIDS, JCV can cause progressive multifocal leukoencephalopathy (PML), a devastating brain disease of high mortality. While JCV in the urine of healthy people has a linear noncoding control region called the archetype NCCR (at-NCCR), JCV in brain and cerebrospinal fluid (CSF) of PML patients bear rearranged NCCRs (rr-NCCRs). Although JCV NCCR rearrangements are deemed pathognomonic for PML, their role as a viral determinant is unclear. We sequenced JCV NCCRs found in CSF of eight HIV/AIDS patients newly diagnosed with PML and analyzed their effect on early and late gene expression using a bidirectional reporter vector recapitulating the circular polyomavirus early and late gene organization. The rr-NCCR sequences were highly diverse, but all increased viral early reporter gene expression in progenitor-derived astrocytes, glia-derived cells, and human kidney compared to the expression levels with the at-NCCR. The expression of simian virus 40 (SV40) large T antigen or HIV Tat expression in trans was associated with a strong increase of at-NCCR-controlled early gene expression, while rr-NCCRs were less responsive. The insertion of rr-NCCRs into the JCV genome backbone revealed higher viral replication rates for rr-NCCR compared to those of the at-NCCR JCV in human progenitor-derived astrocytes or glia cells, which was abrogated in SV40 large T-expressing COS-7 cells. We conclude that naturally occurring JCV rr-NCCR variants from PML patients confer increased early gene expression and higher replication rates compared to those of at-NCCR JCV and thereby increase cytopathology.

Viral proteomics: a promising approach for understanding JC virus tropism

The human polyomavirus JC virus (JCV) is responsible for the CNS demyelination observed in cases of progressive multifocal leukoencephalopathy. The JCV regulatory region (promoter) is a hypervariable, noncoding, nucleotide sequence positioned between the early and late protein-coding regions in the viral genome. Selective binding of cellular transcription factors to this promoter region participates in the control of viral tropism. Hence, further study of these proteins might provide new insights into JCV tropism and associated pathogenesis. This review gives an overview of viral proteomics - the study of all proteins expressed from the viral gene transcripts, and all the cellular proteins that play a role in JCV tropism. It also describes a new biochemical approach for studying relevant JCV promoter-binding proteins, which is an anchored-JCV transcriptional promoter (ATP) assay. An ATP assay utilizes the product of PCR-amplified JCV promoter sequences coupled with Sepharose beads in order to capture and isolate cellular nuclear proteins with specific promoter-binding affinity for analysis. Proteins that bind to JCV-ATPs can be eluted and subjected to proteomic analysis. Insights from this approach may improve the understanding of viral and cellular parameters that control JCV tropism.

Demyelinating diseases

A diagnosis of demyelination carries important therapeutic and prognostic implications. In most cases the diagnosis is made clinically, and involvement of the histopathologist is largely confined to postmortem confirmation and clinicopathological correlation. However, every now and then, accurate diagnosis of the presence or cause of demyelination before death hinges on the histopathological assessment. Recognition of demyelination depends on an awareness of this as a diagnostic possibility, and on the use of appropriate tinctorial and immunohistochemical stains to identify myelin, axons and inflammatory cells. In biopsy specimens, the critical distinction is usually from ischaemic or neoplastic disease, and the types of demyelinating disease most likely to be encountered are multiple sclerosis, acute-disseminated encephalomyelitis, progressive multifocal leucoencephalopathy and extrapontine myelinolysis. Interpretation of the pathology has to be made in the context of the clinical, radiological and biochemical findings. Freezing of a small amount of fresh tissue allows for later virological studies, and electron microscopy is occasionally helpful for demonstration of viral particles.

A case report of progressive multifocal leukoencephalopathy in a human T-cell lymphotropic virus type 1-infected hemodialytic patient

We experienced a case manifesting progressive multifocal leukoencephalopathy (PML) in a hemodialytic patient with hepatitis C virus-induced liver cirrhosis and human T-cell lymphotropic virus type-1 (HTLV-1)-associated uveitis. A 57-year-old male patient had received chronic hemodialysis therapy for 10 years, during which he received multiple blood transfusions and HTLV-1-associated uveitis developed. He complained of visual disturbance and disorientation. Brain CT scan showed diffuse and multifocal low density areas in occipital and temporal lobes, with gray matter relatively spared. MRI imaging showed high intensity lesions in the same areas. Cerebrospinal fluid culture was negative, but using nested PCR, rearranged regulatory region of JC virus DNA was detected. His consciousness level gradually deteriorated and complete paraplegia developed. Seven months after admission, he died of pneumonia. An autopsy confirmed the diagnosis of PML. Notably, mononuclear cell infiltration, gliosis and demyelinating lesions but no nuclear inclusion bodies were observed in the thoracic cord, which suggested HTLV-1-associated myelopathy. Because JC virus is activated under immunocompromised conditions, precipitating factors in this case appear multifactorial; depressed immune system induced by chronic hemodialysis as well as blood-borne hepatitis C virus/HTLV-1 infection might contribute to the activation of dormant JC virus and the development of florid clinical manifestation of PML.

Specific and quantitative detection of human polyomaviruses BKV, JCV, and SV40 by real time PCR

BACKGROUND

The polyomaviruses that infect humans, BK virus (BKV), JC virus (JCV), and simian virus 40 (SV40), typically establish subclinical persistent infections. However, reactivation of these viruses in immunocompromised hosts is associated with renal nephropathy and hemorrhagic cystitis (HC) caused by BKV and with progressive multifocal leukoencephalopathy (PML) caused by JCV. Additionally, SV40 is associated with several types of human cancers including primary brain and bone cancers, mesotheliomas, and non-Hodgkin's lymphoma. Advancements in detection of these viruses may contribute to improved diagnosis and treatment of affected patients.

OBJECTIVE

To develop sensitive and specific real time quantitative polymerase chain reaction (RQ-PCR) assays for the detection of T-antigen DNA sequences of the human polyomaviruses BKV, JCV, and SV40 using the ABI Prism 7000 Sequence Detection System.

STUDY DESIGN

Assays for absolute quantification of the viral T-ag sequences were designed and the sensitivity and specificity were evaluated. A quantitative assay to measure the single copy human RNAse P gene was also developed and evaluated in order to normalize viral gene copy numbers to cell numbers.

RESULTS

Quantification of the target genes is sensitive and specific over a 7 log dynamic range. Ten copies each of the viral and cellular genes are reproducibly and accurately detected. The sensitivity of detection of the RQ-PCR assays is increased 10- to 100-fold compared to conventional PCR and agarose gel protocols. The primers and probes used to detect the viral genes are specific for each virus and there is no cross reactivity within the dynamic range of the standard dilutions. The sensitivity of detection for these assays is not reduced in human cellular extracts; however, different DNA extraction protocols may affect quantification.

CONCLUSION

These assays provide a technique for rapid and specific quantification of polyomavirus genomes per cell in human samples.

Progressive multifocal leukoencephalopathy in an HTLV-I carrier

This report describes a previously 28-year-old healthy woman, identified as an asymptomatic human T-lymphotropic virus type I (HTLV-I) carrier, who developed both progressive multifocal leukoencephalopathy (PML) and Pneumocystis jiroveci pneumonia. For diagnostic confirmation of PML, stereotactic brain biopsy demonstrated multiple demyelinating lesions with the presence of JC viral antigen. Intramuscular alpha-interferon therapy for 2 weeks brought considerable neurologic improvement. Three years later, the patient developed lymphoma-type of adult T-cell leukemia, suggesting that HTLV-I carrier might be one of the underlying diseases of PML.

Frequent detection of Epstein-Barr Virus and cytomegalovirus but not JC virus DNA in cerebrospinal fluid samples from human immunodeficiency virus-infected patients in northern Thailand

Applying nested-PCRs, we frequently detected DNA of Epstein-Barr virus and cytomegalovirus but not JC virus in cerebrospinal fluid samples from 140 human immunodeficiency virus-infected patients with central nervous system symptoms in northern Thailand. Despite the low incidence of primary central nervous system lymphoma or cytomegalovirus encephalitis among Thai AIDS patients, Epstein-Barr virus and cytomegalovirus infections in the central nervous system are common.

Identification of a unique BK virus variant in the CNS of a patient with AIDS

Human polyomavirus BK (BKV; GenBank or EMBL or DDBJ accession no. NC001538) is often reactivated in immunosuppressed patients. Reactivation has been associated primarily with excretion of the virus in the urine, and there have been few reports of renal and/or neurological disease caused by BKV in patients with acquired immunodeficiency syndrome (AIDS). Polymerase chain reaction, Southern blotting, and sequencing were used to detect and identify the noncoding control region (NCCR) of BKV in different tissues in an AIDS patient with meningoencephalitis, retinitis, and nephritis. An undescribed reorganized NCCR variant of the virus, completely different from the variants detected in peripheral blood leukocytes (PBLs) and urine, was identified in the cerebrospinal fluid (CSF) and CNS tissues. These results suggest that rearrangements in the NCCR of the virus have resulted in a BKV variant, which is better adapted to the host cell machinery of the cells in CNS tissue. The rearranged variant (BKV CNS) might have been involved in the initiation and/or development of the pathological lesions observed in the CNS-related tissues of this patient.

JC virus load in progressive multifocal leukoencephalopathy: analysis of the correlation between the viral burden in cerebrospinal fluid, patient survival, and the volume of neurological lesions

JC virus (JCV) is the causative agent of progressive multifocal leukoencephalopathy (PML), a demyelinating central nervous system infection that mainly affects patients with acquired immunodeficiency syndrome. The diagnostic value of the detection of JCV DNA in cerebrospinal fluid (CSF) has been proved. A correlation between the JCV burden in CSF and the PML prognosis has been proposed. To our knowledge, the present study is the first to examine JCV burden in CSF in relation to the magnitude of neurological damage. An in-house quantitative polymerase chain reaction assay was used for measurement of the JCV burden in CSF samples from 12 patients with PML. A wide variation in JCV load (6.4 log) was found among the patient CSF samples, a finding that makes JCV load measurements worthwhile. Virus load values of >4.68 log were associated with shorter patient survival time. No correlation was found between the virus load values and the global volume of brain tissue damaged. Our data suggest that factors other than the volume of neurological lesions influence the shedding of JCV in the CSF.

A classification scheme for human polyomavirus JCV variants based on the nucleotide sequence of the noncoding regulatory region

The human polyomavirus JCV is responsible for the central nervous system (CNS) demyelination observed in cases of progressive multifocal leukoencephalopathy (PML). Lytic infection of oligodendrocytes, the cells that constitute the basis of myelin in the CNS, is established by JCV in conjunction with immunosuppressive conditions. Beyond this, however, many questions related to JCV pathogenesis remain unanswered. The JCV regulatory region is a hypervariable noncoding sequence positioned between the early and late protein-coding regions. The particular nucleotide sequence of a JCV regulatory region affects levels of viral transcription and replication. Modifications to this promoter/enhancer structure can alter the cellular host range and may be responsible for switching JCV between states of lytic and latent infection. The regulatory region structure has, therefore, been used to distinguish JCV variants. Nucleotide sequencing studies have uncovered numerous variations of regulatory region structure. Until now, however, no inclusive nomenclature existed that linked variants by regulatory region structure and/or activity. We have arranged all known variant JCV regulatory regions into quadrants according to the integration of particular sequence sections and repetition of sequence section groups. This arrangement of regulatory regions results in an updated nomenclature that is well-suited for describing the relationships between JCV variants. Four distinct structural forms (I-S, I-R, II-S, and II-R) are defined along with tissue tropisms. This design provides logical connections between the variant regulatory regions and may be useful for elucidating crucial steps in JCV pathogenesis.

Infection with JC virus and possible dysplastic ganglion-like transformation of the cerebral cortical neurons in a case of progressive multifocal leukoencephalopathy

Infection of the cerebral cortical neurons with JC virus (JCV) with possible dysplastic ganglion-like alteration of the infected neurons found in a case of progressive multifocal leukoencephalopathy (PML) is described. The patient was a 21-year-old man with common variable immunodeficiency who died of PML after a 9-month clinical course. At autopsy, the white matter of the cerebrum, brainstem, cerebellum, and spinal cord exhibited extensive demyelination and necrosis. Numerous inclusion-bearing oligodendrocytes and bizarre astrocytes were found. In the occipital and temporal cortex, thick band-like aggregates of dysplastic ganglion-like cells (DGLCs) were found. These DGLCs showed immunohistochemical properties of neurons, and nuclei of some DGLCs were immunoreactive for large T antigen of SV40/JCV and p53, but not for capsid protein JCV VP1. In situ hybridization for mRNA of JCV large T antigen revealed positive signals in the nuclei of some DGLCs. These results indicate that JCV infected neurons and it is suggested that binding of the large T antigen with cellular proteins could have resulted in the dysplastic, ganglion cell-like change of the infected neurons, although the possibility that the aggregates of DGLCs represent a pre-existent malformative lesion of the cortex cannot be excluded completely.

Quantification of human polyomavirus JC in brain tissue and cerebrospinal fluid of patients with progressive multifocal leukoencephalopathy by competitive PCR

Activation of human polyomavirus JC (JCV) infection is the cause of the central nervous system (CNS) disease progressive multifocal leukoencephalopathy (PML). Previous studies with uncontrolled quantification systems suggested that the virus load in the CNS correlates with the state of disease and might reflect therapeutic effects. Therefore the aim of this study was the development of a competitive system with standard PCR techniques that allowed rapid detection of JCV subtypes, simultaneous differentiation of the two human polyomaviruses JCV and BKV and absolute quantification of the virus burden in initial diagnosis and progressive disease states. Subtype- and species-specificity of the PCR was achieved with the development of a degenerative PCR primer pair that detected JCV DNA in a range regularly found in PML samples, but did not amplify BKV DNA. The accuracy of the system was evaluated by quantification of known amounts of cloned JCV DNA with a competitive JCV-specific template that exhibited a comparable amplification rate to that of the native product. The calibration study demonstrated a linear correlation over a wide range of DNA concentrations on the background of buffer or JCV-negative diagnostic samples. The reliability of the system for PML diagnosis was analysed by calibration and determination of the virus burden in tissue and cerebrospinal fluid (CSF) of 11 PML patients confirming the accuracy in both types of samples under diagnostic conditions. Comparison of the JCV DNA concentration in tissue and CSF by a tightly controlled quantification technique revealed for the first time differences in a range of about four orders of magnitude and a variable virus load in CSF samples taken at comparable states of disease. This pointed to an individual course of virus shedding and demonstrates that a controlled competitive PCR system of high accuracy is essential for reliable quantification of virus DNA either in initial diagnosis, in progressive disease or for the evaluation of therapeutic effects.

Progressive multifocal leukoencephalopathy and JC virus genotypes in West African patients with acquired immunodeficiency syndrome: a pathologic and DNA sequence analysis of 4 cases

OBJECTIVE

Progressive multifocal leukoencephalopathy is caused by polyomavirus JC in immunosuppressed patients. JC virus genotypes are identified by sequence analysis of the viral genome. Despite the prevalence of acquired immunodeficiency syndrome in sub-Saharan Africa, few cases of progressive multifocal leukoencephalopathy have been reported from this region. Here we describe 4 African cases and provide an analysis of viral genotypes.

METHODS

Immunohistochemical staining by labeled streptavidin-biotin for capsid protein antigen was performed on all cases. Polymerase chain reaction amplification of viral genomic DNA was followed by direct cycle sequencing.

RESULTS

JC virus type 3 was identified in 2 cases, and type 6 was isolated in 1 case. The viral regulatory region from 1 case showed an uncommon rearrangement pattern.

CONCLUSIONS

Progressive multifocal leukoencephalopathy in West African patients with acquired immunodeficiency syndrome is caused by African genotypes of JC virus (types 3 and 6). The prevalence of disease in this autopsy series from sub-Saharan Africa (1.5%) was less than has been reported from Europe and the United States (4% to 10%) and may be partly due to biological differences in JC virus genotypes. Further studies will be needed to confirm this observation.

Dual qualitative-quantitative nested PCR for detection of JC virus in cerebrospinal fluid: high potential for evaluation and monitoring of progressive multifocal leukoencephalopathy in AIDS patients receiving highly active antiretroviral therapy

JC polyomavirus (JCV) is the causative agent of progressive multifocal leukoencephalopathy (PML), a central nervous system infection that mainly affects AIDS patients. The extensive application of highly active antiretroviral therapy (HAART) is leading to the appearance of "long-term" survival PML patients. A reliable and feasible qualitative-quantitative test for both the detection of JCV and follow-up of its viral burden in this emerging group of patients is clearly required. With this aim, a dual qualitative-quantitative nested PCR is presented in this study for the analysis of JCV DNA in cerebrospinal fluid (CSF). Two newly designed internal controls, one competitive and the other noncompetitive, have been constructed to adapt this PCR to either measure the JCV burden or to allow a highly confident determination of JCV presence or clearance. The analytical sensitivity of the technique allows the detection of 0.01 fg (three genomes) of JCV DNA. Its qualitative application has been evaluated by analyzing single CSF samples from a group of 17 patients with PML and a control group of 20 patients with diverse neurological conditions other than PML, yielding sensitivity and specificity values of 100 and 90%, respectively. The quantitative application has been evaluated in vitro in blind tests with samples including serial dilutions of JCV, and in all cases the samples were successfully ordered considering the JCV titer. The dual quantitative-qualitative application offered by this nested PCR may provide an answer to the new requirements for evaluating and finely monitoring PML in AIDS patients receiving HAART.

Progressive multifocal leukoencephalopathy in a patient with acquired immunodeficiency syndrome (AIDS) manifesting Gerstmann's syndrome

We reported a case of acquired immunodeficiency syndrome (AIDS) via multiple blood transfusions, who manifested progressive multifocal leukoencephalopathy (PML) about 18 months after the development of AIDS. PML initiated with right hemiparesis, dysphasia, and Gerstmann's syndrome and resulted in death within 2 months after the onset. Neuroimaging examinations revealed white matter lesions mainly in the left posterior parietal lobe. The cortical gray matter also showed abnormal signal intensity. Peripheral CD4+ lymphocyte count was 81/microl. Routine cerebrospinal fluid (CSF) examinations were negative. CSF antibodies against herpes simplex virus, varicella-zoster virus, cytomegalovirus, Epstein-Barr virus as well as serum antibody against toxoplasma gondii were negative. Though autopsy or biopsy of the brain was not performed, JC virus genomes were detected in the CSF sample by a polymerase chain reaction, and their sequencing showed unique alterations of the regulatory regions, characteristic to PML-type JC virus.

Archetype JC virus efficiently replicates in COS-7 cells, simian cells constitutively expressing simian virus 40 T antigen

JC polyomavirus (JCV), the causative agent of progressive multifocal leukoencephalopathy (PML), is ubiquitous in humans, infecting children asymptomatically and then persisting in the kidney. Renal JCV is not latent but replicates to excrete progeny in the urine. The renal-urinary JCV DNAs carry the archetype regulatory region that generates various rearranged regulatory regions occurring in JCVs derived from the brains of PML patients. Tissue cultures that support the efficient growth of archetype JCV have not been reported. We studied whether archetype JCV could replicate in COS-7 cells, simian cells transformed with an origin-defective mutant of simian virus 40 (SV40). Efficient JCV replication, as detected by a hemagglutination assay, was observed in cultures transfected with five of the six archetype DNAs. The progeny JCVs could be passaged to fresh COS-7 cells. However, when the parental cells of COS-7 not expressing T antigen were transfected with archetype JCV DNAs, no viral replication was detected, indicating that SV40 T antigen is essential for the growth of JCV in COS-7 cells. The archetype regulatory region was conserved during viral growth in COS-7 cells, although a small proportion of JCV DNAs underwent rearrangements outside the regulatory region. We then attempted to recover archetype JCV from urine by viral culture in COS-7 cells. Efficient JCV production was observed in COS-7 cells infected with five of the six JCV-positive urine samples examined. Thus, COS-7 cells should be of use not only for the production of archetype JCV on a large scale but also for the isolation of archetype JCV from urine.