Direct isolation and characterization of JC virus from urine samples of renal and bone marrow transplant patients

The biology of JC polyomavirus

JC polyomavirus (JCPyV) is the causative agent of a fatal central nervous system demyelinating disease known as progressive multifocal leukoencephalopathy (PML). PML occurs in people with underlying immunodeficiency or in individuals being treated with potent immunomodulatory therapies. JCPyV is a DNA tumor virus with a double-stranded DNA genome and encodes a well-studied oncogene, large T antigen. Its host range is highly restricted to humans and only a few cell types support lytic infection in vivo or in vitro. Its oncogenic potential in humans has not been firmly established and the international committee on oncogenic viruses lists JCPyV as possibly carcinogenic. Significant progress has been made in understanding the biology of JCPyV and here we present an overview of the field and discuss some important questions that remain unanswered.

JC Polyomavirus Infection of Primary Human Renal Epithelial Cells Is Controlled by a Type I IFN-Induced Response

The JC and BK human polyomaviruses (JCPyV and BKPyV, respectively) establish lifelong persistent infections in the kidney. In immunosuppressed individuals, JCPyV causes progressive multifocal leukoencephalopathy (PML), a fatal neurodegenerative disease, and BKPyV causes polyomavirus-associated nephropathy (PVN). In this study, we compared JCPyV and BKPyV infections in primary human renal proximal tubule epithelial (HRPTE) cells. JCPyV established a persistent infection, but BKPyV killed the cells in 15 days. To identify the cellular factors responsible for controlling JCPyV infection and promoting viral persistence, we profiled the transcriptomes of JCPyV- and BKPyV-infected cells at several time points postinfection. We found that infection with both viruses induced interferon production but that interferon-stimulated genes (ISGs) were only activated in the JCPyV-infected cells. Phosphorylated STAT1 and IRF9, which are responsible for inducing ISGs, translocated to the nucleus of JCPyV-infected cells but did not in BKPyV-infected cells. In BKPyV-infected cells, two critical suppressors of cytokine signaling, SOCS3 and SOCS1, were induced. Infection with BKPyV but not JCPyV caused reorganization of PML bodies that are associated with inactivating antiviral responses. Blockade of the interferon receptor and neutralization of soluble interferon alpha (IFN-α) and IFN-β partially alleviated the block to JCPyV infection, leading to enhanced infectivity. Our results show that a type I IFN response contributes to the establishment of persistent infection by JCPyV in HRPTE cells.

The human polyomaviruses JCPyV and BKPyV both establish lifelong persistent infection in the kidneys. In immunosuppressed patients, BKPyV causes significant pathology in the kidney, but JCPyV is only rarely associated with disease in this organ. The reasons behind this striking difference in kidney pathology are unknown. In this study, we show that infection of primary human renal tubule epithelial cells with JCPyV and BKPyV results in divergent innate immune responses that control JCPyV but fail to control BKPyV. This is the first study that directly compares JCPyV and BKPyV infection in vitro in the same cell type they naturally infect, and the significant differences that have been uncovered could in part explain the distinct disease outcomes.

A prospective study of renal transplant recipients reveals an absence of primary JC polyomavirus infections

BACKGROUND

Both JC polyomavirus (JCPyV) and BK polyomavirus (BKPyV) are acquired at an early age. JCPyV causes progressive multifocal leukoencephalopathy and has been described in association with nephropathy.

OBJECTIVES

Urine and plasma samples from renal transplant recipients (RTRs) were examined for JCPyV to determine its involvement in causing infection and disease.

STUDY DESIGN

JCPyV testing was performed on 112 RTRs included in a randomised controlled study of steroid-sparing immunosuppressive regimens [1]. Urine and EDTA blood samples were collected pre- and post-transplantation and analysed for JCPyV using real-time PCR and sequencing to determine genotype and viral variation. Donor and recipient IgG antibody status to JCPyV was also determined.

RESULTS

Overall, 13.3% of RTRs were positive for JCPyV of which one patient developed viraemia without viruria. JCPyV DNA was detected early following transplantation (defined as five days post transplantation) from recipients with donors that were positive for JCPyV IgG antibodies. No dual cases of JCPyV and BKPyV were observed. One patient sample had sequence duplication in the non-coding control region.

CONCLUSIONS

Like BKPyV, JCPyV tends to occur early post transplantation but did not result in sustained viraemia. There was no deterioration of renal function in patients positive for JCPyV. As with other viruses, JCPyV donor serostatus was a risk factor for detection of JCPyV DNA. JCPyV appears to protect individuals from BKPyV infection, as recipients were twice as likely to develop BKPyV with a negative JCPyV donor.

5-HT2 receptors facilitate JC polyomavirus entry

The human JC polyomavirus (JCPyV) causes the rapidly progressing demyelinating disease progressive multifocal leukoencephalopathy (PML). The disease occurs most often in individuals with AIDS but also occurs in individuals receiving immunomodulatory therapies for immune-related diseases such as multiple sclerosis. JCPyV infection of host cells requires the pentasaccharide lactoseries tetrasaccharide c (LSTc) and the serotonin receptor 5-hydroxytryptamine (5-HT) receptor 5-HT2AR. While LSTc is involved in the initial attachment of virus to cells via interactions with VP1, the mechanism by which 5-HT2AR contributes to infection is not clear. To further define the roles of serotonin receptors in infection, HEK293A cells, which are poorly permissive to JCPyV, were transfected with 14 different isoforms of serotonin receptor. Only 5-HT2 receptors were found to support infection by JCPyV. None of the other 11 isoforms of serotonin receptor supported JCPyV infection. Expression of 5-HT2 receptors did not increase binding of JCPyV to cells, but this was not unexpected, given that the cells uniformly expressed the major attachment receptor, LSTc. Infection of these cells remained sensitive to inhibition with soluble LSTc, confirming that LSTc recognition is required for JCPyV infection. Virus internalization into HEK293A cells was significantly and specifically enhanced when 5HT2 receptors were expressed. Taken together, these data confirm that the carbohydrate LSTc is the attachment receptor for JCPyV and that the type 2 serotonin receptors contribute to JCPyV infection by facilitating entry.

Polyomavirus JC in the context of immunosuppression: a series of adaptive, DNA replication-driven recombination events in the development of progressive multifocal leukoencephalopathy

Polyomavirus JC (JCV) is the etiological agent of progressive multifocal leukoencephalopathy (PML), a demyelinating infection of oligodendrocytes in the brain. PML, a frequently fatal opportunistic infection in AIDS, has also emerged as a consequence of treatment with several new immunosuppressive therapeutic agents. Although nearly 80% of adults are seropositive, JCV attains an ability to infect glial cells in only a minority of people. Data suggest that JCV undergoes sequence alterations that accompany this ability, and these changes can be derived from an archetype strain by mutation, deletion, and duplication. While the introductory source and primary tissue reservoir of JCV remain unknown, lymphoid cells have been identified as potential intermediaries in progression of JCV to the brain. This review is focused on sequence changes in the noncoding control region (NCCR) of the virus. We propose an adaptive mechanism that involves a sequential series of DNA replication-driven NCCR recombination events involving stalled DNA replication forks at NCCR palindromic secondary structures. We shall describe how the NCCR sequence changes point to a model in which viral DNA replication drives NCCR recombination, allowing JCV adaptation to different cell types in its progression to neurovirulence.

Pathogenesis of progressive multifocal leukoencephalopathy--revisited

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system that is rare even though the proven etiological agent of PML, the polyomavirus JC (JC virus), is ubiquitous within the human population. The common feature of PML cases appears to be underlying immunosuppression, and PML has gained clinical visibility because of its association with human immunodeficiency virus and AIDS and its occurrence as a side effect of certain immunomodulatory drugs. A hypothesis has gained general acceptance that JC virus causes a primary infection in childhood and enters a latent state, after which immunosuppression allows viral reactivation leading to PML. Nonetheless, many important aspects of PML pathogenesis remain unclear, including the molecular bases of latency and reactivation, the site(s) of latency, the relationship of archetype and prototype virus and the mode of virus transmission within the body and between individuals. In this review, we will revisit these areas and examine what the available evidence suggests.

JC virus detection in bodily fluids: clues to transmission

JC virus in saliva, oropharyngeal fluid, blood, and urine samples obtained from 58 human immunodeficiency virus-infected persons and 58 matched controls was investigated by performing quantitative polymerase chain reaction. JC virus was rarely present in oropharyngeal fluid and blood samples, even in those obtained from immunosuppressed individuals, but it was commonly detected in urine samples from both groups, suggesting that urine contributes to transmission.

[New trends in progressive multifocal leukoencephalopathy]

Infection by Polyomavirus JC is a model of chronic active viral infection, closely controlled by the immune system. Progressive multifocal leucoencephalopathy (PML) is a deadly demyelinating disease of the central nervous system, consecutive to the lytic infection of oligodendrocytes by JC virus. Reactivation of JC virus occurs only in the setting of severe cellular immune deficiency. During the last 25 years, the incidence of PML has significantly increased related to the AIDS pandemic and, more recently, to the growing use of immunosuppressive drugs. There is no specific antiviral treatment for PML. Nevertheless, the availability of highly active antiretroviral therapy has changed the clinical course of PML in HIV-infected individuals. One-year mortality has decreased from 90 percent to approximately 50 percent as a result of reconstitution of the immune system. Recent advances in JC virus biology give new perspectives to the pathogenesis of PML. New trends in the understanding of the cellular immune response against the JC virus have direct implications for patient management and may lead to develop future strategy of immunotherapies for PML.

Prevalence, characteristics, and outcome of BK virus nephropathy in Japanese renal transplant patients: analysis in protocol and episode biopsies

BACKGROUND

BK virus nephropathy (BKN) is recognized as a cause of graft loss in renal transplant patients. This may be related to the introduction of new and potent immunosuppressive regimens. In Japan, our experience regarding its prevalence, clinical significance, and outcome is still limited. In this study, our primary purpose is to outline the prevalence, outcome, and clinical characteristics of BKN as observed at Osaka University Hospital.

METHODS

We retrospectively analyzed 112 biopsy specimens from 87 renal transplant patients. All transplantations were from living donors. Of the 112 biopsy specimens, 71 were from protocol biopsies and 41 were from episode biopsies. Calcineurin inhibitors and corticosteroid were used in all patients (tacrolimus 32 and cyclosporin 55). In addition, azathioprine was used in 43 patients, mizoribine was used in 24 patients, and mycophenolate mofetil was used in 20 patients. BKN was diagnosed by light microscopic examination and a positive immunohistochemical staining of anti-SV40 antibody in a biopsy specimen. In order to investigate the outcome and potential risk factors of patients with different histological staging, we divided the patients into groups A (mild histological change) and B (moderate or severe histological change).

RESULTS

Of the 87 patients, six were diagnosed with BKN. There were no significant differences between BKN patients and non-BKN patients, except for the number of patients with graft loss (p < 0.001). Of the six BKN patients, three were in group A, and three were in group B. We recognized a significant difference between group A and group B in terms of anti-rejection treatment including glucocorticoid, tacrolimus trough levels of over 8 ng/mL, episode of acute rejection within 1-month post-transplantation, and the time period between transplantation and BKN diagnosis.

CONCLUSIONS

This is the first report of BKN in Japanese renal allograft recipients. In our hospital, the prevalence, risk factors, and outcome were similar to those previously for non-Japanese recipients.

Polyoma nephropathy and progressive multifocal leukoencephalopathy in a renal transplant recipient

Progressive multifocal leukoencephalopathy is a progressive and ultimately fatal white-matter disease of the brain that is associated with polyomavirus infection. It is uncommon in the general population, and even in the immunosuppressed patient, who is inherently at greatest risk for active infection with the virus, it is rare. The causative agent in progressive multifocal leukoencephalopathy, JC virus, has become increasingly important in recent years as its role in nephropathy in the renal transplant recipient has become better understood. We present a young renal transplant patient who developed nephropathy with renal biopsy changes consistent with polyomavirus lesions and then developed mental status changes and was diagnosed with progressive multifocal leukoencephalopathy.

High incidence of JC viruria in JC-seropositive older individuals

The prevalence of the human JC virus (JCV) in the general population at various ages was investigated. Polymerase chain reaction was employed to detect viral DNA in the urine. The results showed that the incidence of JC viruria was low in the young population, but it was high in the elderly. Hemagglutination inhibition assay was performed for JCV seroprevalence study. The results showed that the seropositive rate of JCV was lower in children than that in adults. The ratio of viruria to seropositive for JCV increased with age and reached 79.7% for those older than 70 years. The results indicated that aging immunity may correlate with JCV reactivation.

A regulatory region rearranged BK virus is associated with tubulointerstitial nephritis in a rejected renal allograft

A renal allograft transplant patient with high serum creatinine presented clinical symptoms of rejection. Sections of renal biopsy tissue showed mononuclear leukocyte infiltration in the tubulointerstitium and nuclear enlargement with inclusions in the tubular epithelium. The morphological characteristics resembled polyomavirus-induced interstitial nephritis. Electron microscopy of the nuclear inclusions showed paracrystalline arrays of naked viral particles with a diameter of 45 nm. Molecular studies revealed that a new variant of BK virus (BKV) with rearrangement at the regulatory region was involved in the nephritis. The BKV regulatory region contained a tandem repeat from the P-block to the Q-block causing duplication of several important transcriptional elements or transcriptional factor binding motifs. This is the first report to show a naturally occurring BKV variant with regulatory region rearrangement associated with tubulointerstitial nephritis.

JC virus DNA sequences are frequently present in the human upper and lower gastrointestinal tract

BACKGROUND & AIMS

JC virus (JCV), a human polyomavirus, has been found in a limited number of normal human tissues and cancers. The oncogenic potential of this virus is mediated by a transforming protein, the T antigen (TAg). We have previously demonstrated the presence of JCV-TAg in colorectal cancers, in adjacent normal colonic mucosa from these patients, and in the human colon cancer cell line SW480. The mode of transmission of this virus is unclear, and we hypothesized that the gastrointestinal (GI) tract may be a reservoir for the virus.

METHODS

DNA was extracted from 129 normal GI tissue samples collected from 33 patients. Topoisomerase I-assisted polymerase chain reaction (PCR) was used to detect the virus using exact and degenerate primers. Nested PCR and Southern blot analysis confirmed the identity of the PCR products. Single-stranded conformation polymorphism (SSCP) analysis and sequencing were used to evaluate the presence of viral quasispecies.

RESULTS

JCV sequences were found in 75.8% of patients (70.6% of upper GI and 81.2% of colonic samples); no significant differences in rates of infection were found by site. The use of degenerate primers combined with topoisomerase I treatment led to viral detection in 58.9% of samples, compared with 27.9% of samples using exact primers and topoisomerase I (P < 0.01). SSCP and sequencing analysis confirmed the amplification of viral quasispecies and the authenticity of TAg sequences.

CONCLUSIONS

The results show that JCV DNA sequences are highly prevalent in the human upper and lower gastrointestinal tract of immunocompetent individuals.

Human anti-JC virus serum reacts with native but not denatured JC virus major capsid protein VP1

The immunoreactivity of human anti-JC virus (JCV) serum against the major capsid protein VP1 of JCV was analyzed by Western blot, dot blot, and hemagglutination inhibition (HAI) assays. JCV-positive human serum reacted with native but not denatured JCV major capsid protein VP1, as demonstrated by dot blot and Western blot. Rabbit antiserum raised against native JCV capsid had immunoreactivities similar to those of human anti-JCV serum. These results indicate that the antigenecity of native and denatured JCV VP1 is different. In addition, both JCV-positive human serum and rabbit antiserum raised against native JCV capsid protein inhibited the hemagglutination activity of JCV capsid particles. In contrast, rabbit antiserum raised against denatured JCV VP1 did not inhibit hemagglutination. These findings reveal that denaturation may alter the antigenic epitopes of JCV VP1. Therefore, keeping the JCV capsid protein native appears to be essential for serological or other immunological analyses of the virus.

Human ubiquitous JCV(CY) T-antigen gene induces brain tumors in experimental animals

JCV is a papovavirus which is widespread in the human population. The prototype Mad-1 variant of JCV induces a fatal demyelinating disease of the central nervous system (CNS) called Progressive Multifocal Leukoencephalopathy (PML) in immunosuppressed individuals. The unique tropism of JCV (Mad-1) to the CNS is attributed to the tissue-specific regulation of the viral early promoter which is responsible for the production of the viral regulatory protein, T-antigen. The archetype form of this virus, JCV(CY), which has been repeatedly isolated from the urine of PML and non-PML individuals, is distinct from JCV(Mad-1) in the structural organization of the regulatory sequence. To characterize the tissue specific expression of JCV(CY) and to investigate its potential in inducing disease, transgenic mice containing the early region of JCV(CY) were generated. Some of these mice between 9-13 months of age exhibited signs of illness as manifested by paralysis of rear limbs, hunched posture, and poor grooming. Neuropathological examination indicated no sign of hypomyelination of the brain, but surprisingly, revealed the presence of primitive tumors originating from the cerebellum and the surrounding brain stem. The tumor masses also infiltrated the surrounding tissue. Results from RNA and protein studies revealed a high level of T-antigen mRNA expression in hindbrains of clinically normal and affected transgenic mice. However, higher levels of T-antigen RNA and protein were detected in brains of the animals exhibiting severe illness. The close resemblance of JCV(CY) induced tumor in transgenic mice to the human medulloblastoma/primitive neuroectodermal tumor (PNETs) in location, histologic appearance, and expression of marker proteins strongly suggests the utility of this novel animal model for the study of human brain tumors.

Detection of JC virus DNA in human tonsil tissue: evidence for site of initial viral infection

Progressive multifocal leukoencephalopathy is a demyelinating disease of the human central nervous system that results from lytic infection of oligodendrocytes by the polyomavirus JC (JCV). Originally, JCV was thought to replicate exclusively in human glial cells, specifically oligodendrocytes. However, we have recently shown that JCV can replicate in cells of lymphoid origin such as hematopoietic precursor cells, B lymphocytes, and tonsillar stromal cells. To determine whether tonsils harbor JCV, we tested a total of 54 tonsils, 38 from children and 16 from adult donors. Nested PCRs with primer sets specific for the viral T protein and regulatory regions were used for the detection of JCV DNA. JCV DNA was detected in 21 of 54 tonsil tissues, or 39% (15 of 38 children and 6 of 16 adults) by using regulatory-region primers and in 19 of 54 tonsil tissues, or 35% (13 of 38 children and 6 of 16 adults) by using the T-protein primers. The DNA extracted from children's nondissected tonsil tissue, isolated tonsillar lymphocytes, and isolated stromal cells that demonstrated PCR amplification of the JCV regulatory region underwent cloning and nucleotide sequencing. Of the regulatory-region sequences obtained, nearly all contained tandem repeat arrangements. Clones originating from nondissected tonsil tissue and tonsillar lymphocytes were found to have sequences predominantly of the Mad-1 prototype strain, whereas the majority of clones from the DNA of tonsillar stromal cells had sequences characteristic of the Mad-8br strain of JCV. A few clones demonstrated structures other than tandem repeats but were isolated only from tonsillar lymphocytes. These data provide the first evidence of the JCV genome in tonsil tissue and suggest that tonsils may serve as an initial site of viral infection.

Transcription of the JC virus archetype late genome: importance of the kappa B and the 23-base-pair motifs in late promoter activity in glial cells

The transcription control region of the archetype strain of the human polyomavirus JC virus (JCV(Cy)), unlike its neurotropic counterpart (JCV(Mad-1)), contains only one copy of the 98-bp enhancer/promoter repeat with the 23-bp and the 66-bp insertion blocks. Early studies by us and others have indicated that the structural organization of JCV(Mad-1) is critical for glial cell-specific transcription of the viral genome. In addition, the kappa B regulatory motif found in the JCV(Mad-1) genome, which also exists in JCV(Cy), confers inducibility to the JCV(Mad-1) early and late promoters in response to extracellular stimuli. In this study, we have investigated the regulatory role of the 23- and the 66-bp blocks and their functional relationship to the kappa B motif in stimulating transcription of the Cy early and late promoters in glial cells. We demonstrate that mutations in the kappa B motif reduce the basal activity of the Cy early promoter and decrease the levels of its induction by phorbol myristate acetate or factors derived from activated T cells. Under similar circumstances, mutation in the kappa B motif completely abrogated the basal and the induced levels of transcription of the viral late promoter. Using deletion and hybrid promoter constructs, we have demonstrated that the 23-bp block of the Cy promoter plays a critical role in the observed inactivation of Cy late promoter transcription in glial cells. Results from DNA binding studies have indicated the formation of a common nucleoprotein complex with the 23-bp sequence, mutant kappa B (kappa B(mut)), and wild-type kappa B (kappa B(wt)). Analysis of this complex by UV cross-linking has identified a 40-kDa protein which binds to the 23-bp sequence and the kappa B motif. The importance of these findings for the activation of JCV(Cy) under various physiological conditions is discussed.

Different genotypes of human polyomaviruses found in patients with autoimmune diseases in Taiwan

We have assayed for the presence of human polyomaviruses in urine of autoimmune disease patients, such as systemic lupus erythematosus (SLE), Sjogren's syndrome (SS), rheumatoid arthritis (RA), or dermatomyositis/polymositis (DM/PM), by PCR. The results indicate that approximately 40% of patients were JCV positive and 15% of the JCV positive patients were also infected by BKV at the same time according to Southern blot and DNA sequencing of the PCR products. Interestingly, the JCV present in autoimmune diseases patients were Taiwan-1, Taiwan-2, and Taiwan-3 strains with pentanucleotide-A (GGGAA) and/or -B (AAAGC) deletions within the regulatory region. In addition, BKV found in the examined samples were Taichung-1 and Taichung-2 strains. Taichung-1 had two nucleotide alterations and Taichung-2 had six nucleotide differences within the regulatory region when compared to WW BKV archetype. Although the examined autoimmune diseases patients included RA, SLE, PM, DM, and SS patients, there appears to be no correlation between disease and virus strains. However, Taiwan-2 strain JCV with two copies of pentanucleotide-A deletion was present in the patient with the longest period of immunosuppressive medication.

Detection of BK virus DNA in nasopharyngeal aspirates from children with respiratory infections but not in saliva from immunodeficient and immunocompetent adult patients

Our understanding of important stages in the pathogenesis of the human polyomavirus BK virus (BKV) and JC virus (JCV) infections is limited. In this context, nasopharyngeal aspirates from 201 children with respiratory diseases and saliva from 60 human immunodeficiency virus type 1-infected adults and 10 healthy adult controls were collected and analyzed for the presence of BKV and JCV DNA by PCR. Neither BKV nor JCV DNA was detected in the saliva specimens. We demonstrated BKV DNA, but no infectious BKV, in 2 of 201 nasopharyngeal aspirates. Each sample contained one unique rearranged noncoding control region variant of BKV. The results indicate that (i) BKV and JCV are not regularly associated with respiratory infections in children requiring hospitalization, (ii) nasopharyngeal cells are not an important site for primary replication of human polyomavirus BKV and JCV, and (iii) the salivary glands and oropharyngeal cells seem not to be involved in BKV and JCV persistence. We propose that for the polyomaviruses BKV and JCV the alimentary tract should be considered as a portal of entrance to the human organism.

Detection by PCR of human polyomaviruses BK and JC in immunocompromised individuals and partial sequencing of control regions

Immunocompromised individuals were tested for the presence of the human polyomaviruses JC (JCV) and BK (BKV) by the polymerase chain reaction (PCR). The use of appropriate primers in a nested PCR allowed the detection of both viruses simultaneously. Viruses were differentiated by restriction fragment length analysis of amplified DNA fragments. Both BKV and JCV DNA were detected in the urine of an AIDS patient with progressive multifocal leukencephalopathy. In autopsy materials from this patient, JCV- but not BKV-DNA was found in brain and kidney tissue, whereas lung tissue was negative for both virus DNAs. To evaluate the methodology further, hybridization-positive urines from three recipients of bone marrow transplants and a positive urine of an acute myeloid leukemia patient were analyzed by this PCR method. One case was positive both for BKV and JCV, two cases were positive only for BKV, and one was negative for both. Parts of the control regions of JCV and BKV were sequenced directly from PCR-derived fragments. The JCV sequence from urine of the AIDS patient compared to sequences from a bone marrow transplant recipient and to archetypical reference strains showed two nucleotide (nt) exchanges out of 250 nt. The BKV sequences from the AML and the AIDS patients showed five nt exchanges out of 265 nt in the control region and were identified as BKV WW or WWT3 strains. In the agnogene region five exchanges were detected, two of them resulting in non-conservative amino acid exchanges. The possibility of testing clinical specimens of different origins by this PCR method is important for elucidating often unclear clinical courses in immunocompromised patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Progressive multifocal leukoencephalopathy in AIDS: a clinicopathologic study and review of the literature

We reviewed the clinical, radiographic, and pathologic features of 15 patients with the acquired immune deficiency syndrome (AIDS) and progressive multifocal leukoencephalopathy (PML). Brain tissue from 10 autopsy and 6 biopsy specimens was studied using: in situ hybridization (ISH) for JC virus (JCV), immunohistochemistry for human immunodeficiency virus (HIV) p24 antigen, and electron microscopy. Thirteen patients presented with focal neurologic deficits, while 2 presented with a rapid decline in mental status. PML was commonly the initial opportunistic infection of AIDS and produced hemiparesis, dementia, dysarthria, cerebellar abnormalities, and seizures. Magnetic resonance imaging was more sensitive than computed tomography in detecting lesions, and often showed multifocal areas of PML. CD4+ T-cell counts were uniformly low (mean 84/mm3), except in 1 patient who improved on 3'-azido-3'-deoxythymidine (AZT). PML involved the cerebral hemispheres, brain stem, cerebellum, and cervical spinal cord. The distribution of brain involvement was consistent with hematogenous dissemination of the virus. In 2 brain specimens, multiple HIV-type giant cells were present within the regions involved by PML. When co-infection by HIV and papovavirus was present, PML dominated the pathological picture. ISH for JCV showed virus in the nuclei of oligodendrocytes and astrocytes. Occasionally there was staining for JCV in the cytoplasm of glial cells and in the neuropil, the latter possibly a correlate of papovavirus spread between myelin sheaths, as seen by electron microscopy. ISH demonstrated more extensive foci of PML than did routine light microscopy.

Origin of JC polyomavirus variants associated with progressive multifocal leukoencephalopathy

JC polyomavirus (JCV) DNAs from the urine of nonimmunocompromised individuals (designated archetypal isolates) regularly contain a regulatory sequence that may have generated various regulatory sequences of JCV isolates derived from the brain of patients with progressive multifocal leukoencephalopathy (PML). In this report, we constructed a phylogenetic tree for 14 isolates (7 archetypes and 7 PML types) from DNA sequence data on the VP1 (major capsid protein) gene. According to the phylogenetic tree, the 14 isolates diverged into types A and B, each of which contained archetypal and PML-type isolates. Each type further diverged into several groups containing archetypal and PML-type isolates. We conclude that PML-type isolates are polyphyletic in their origin and do not constitute a unique lineage. This conclusion suggests that PML-type JCV isolates are generated from archetypal strains during persistence in the hosts. Furthermore, the present phylogenetic analysis indicates that an ancestral JCV carried the archetypal regulatory sequence and that this structure has been conserved in the course of JCV evolution.

JC virus DNA is present in many human brain samples from patients without progressive multifocal leukoencephalopathy

Sections of normal and diseased brain and kidney tissues were screened for the presence of JC virus (JCV) DNA by using the polymerase chain reaction. As expected, all samples obtained from patients with progressive multifocal leukoencephalopathy (PML) tested positive when multiple JCV-specific primer and probe combinations were used. Unexpectedly, more than 50% of non-PML-affected brains were also found to harbor low levels of JCV DNA. To confirm that the positive signals seen in the tissue sections were not the result of contamination, amplified DNA was cloned and sequenced and in some cases was shown to represent strains of JCV not identified previously. Two predominant regulatory region configurations of JCV have been detected in the human host: archetype JCV, which is excreted in the urine of normal and immunocompromised individuals, and "PML-type" JCV found in diseased brains. This latter group of variants appears to derive from archetype JCV by the deletion and duplication of sequences within the promoter-enhancer region. In the present study, the archetype strain of JCV was identified only in normal kidney samples; JCV DNA found in non-PML-affected brain specimens and in kidney tissue from patients with PML resembled that of strains isolated from PML-affected brain tissue. Our findings indicate that JCV reaches the brain more frequently than previously thought and may persist at this site without causing demyelinating disease. A subsequent episode of prolonged immunodeficiency or a direct interaction with an immunocompromising agent (e.g., human immunodeficiency virus type 1) might activate the latent JCV infection and lead to the development of PML.

Detection of JC virus in the brains of aged patients without progressive multifocal leukoencephalopathy by the polymerase chain reaction and Southern hybridization analysis

Ninety-one brain tissue sections taken at autopsy from 33 elderly patients (63-100 years old) without progressive multifocal leukoencephalopathy were examined for the presence of JC virus DNA by the polymerase chain reaction and Southern hybridization analysis after DNA extraction. JC virus DNA was detected in 15 sections from 10 patients. These results suggest that JC virus is frequently present in the brains of aged patients.

Detection of human immunodeficiency virus type 1 (HIV-1) in urine cell pellets from HIV-1-seropositive individuals

Fresh urine pellets from human immunodeficiency virus type 1 (HIV-1)-seropositive individuals were examined for the presence of the HIV-1 genomic sequence and gene products. By using the polymerase chain reaction technique, HIV-1 DNA proviral sequences were detected in 53 of 80 (66.25%) fresh urine pellets from HIV-1-seropositive individuals, while urine pellets from all 24 healthy heterosexual controls were negative. HIV-1 RNA in urine pellets was detected by reverse transcriptase polymerase chain reaction in 2 of 43 (4.7%) HIV-1-seropositive individuals. In addition, HIV-1 p24 core antigen was demonstrated in 3 of 80 urine pellets from HIV-1-seropositive individuals by enzyme-linked immunosorbent assay. Moreover, HIV-1 p24 core antigen and HIV-1 RNA were shown in the cellular component of urine pellets from HIV-1-seropositive individuals by immunohistochemical staining and in situ hybridization. These results indicate that HIV-1 can be present in urine pellets from HIV-1-infected individuals.

Detection of JC virus DNA in peripheral lymphocytes from patients with and without progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) results from lytic infection of oligodendrocytes by JC virus (JCV). Although JCV has been identified in mononuclear cells in bone marrow and hematogenous dissemination of the virus to the central nervous system has been suspected, JCV has never been clearly demonstrated in the peripheral circulation. Using polymerase chain reaction technology, we examined peripheral lymphocytes of 19 patients with brain biopsy-proven PML for the JCV genome. Two non-PML control groups, consisting of 26 patients seopositive for human immunodeficiency virus type 1 (HIV-1) and 30 immunocompetent patients with Parkinson's disease, were also examined for the presence of the JCV genome in lymphocytes. Cerebrospinal fluid from 10 patients with PML was examined for the presence of the JCV genome as well. The JCV genome was detected in the lymphocytes of 89% (17) of the patients with PML, 38% (10) of the HIV-1-seropositive patients without PML, and none of the patients with Parkinson's disease. Sequencing of the JCV regulatory region from the lymphocytes of three patients revealed the prototype MAD-1 strain of JCV in one patient with PML, a MAD-4 strain in a second patient with PML, and a slightly modified MAD-4 strain in an HIV-1-positive patient without PML. Only 3 of 10 patients with PML who had JCV detected in lymphocytes had the JCV genome in their cerebrospinal fluid. These results demonstrate that the JCV genome can be found in circulating lymphocytes from patients with PML and suggest that lymphocytes are an important vector for hematogenous dissemination of JCV to the central nervous system.(ABSTRACT TRUNCATED AT 250 WORDS)

Pathogenesis and molecular biology of progressive multifocal leukoencephalopathy, the JC virus-induced demyelinating disease of the human brain

Studies of the pathogenesis and molecular biology of JC virus infection over the last two decades have significantly changed our understanding of progressive multifocal leukoencephalopathy, which can be described as a subacute viral infection of neuroglial cells that probably follows reactivation of latent infection rather than being the consequence of prolonged JC virus replication in the brain. There is now sufficient evidence to suggest that JC virus latency occurs in kidney and B cells. However, JC virus isolates from brain or kidney differ in the regulatory regions of their viral genomes which are controlled by host cell factors for viral gene expression and replication. DNA sequences of noncoding regions of the viral genome display a certain heterogeneity among isolates from brain and kidney. These data suggest that an archetypal strain of JC virus exists whose sequence is altered during replication in different cell types. The JC virus regulatory region likely plays a significant role in establishing viral latency and must be acted upon for reactivation of the virus. A developing hypothesis is that reactivation takes place from latently infected B lymphocytes that are activated as a result of immune suppression. JC virus enters the brain in the activated B cell. Evidence for this mechanism is the detection of JC virus DNA in peripheral blood lymphocytes and infected B cells in the brains of patients with progressive multifocal leukoencephalopathy. Once virus enters the brain, astrocytes as well as oligodendrocytes support JC virus multiplication. Therefore, JC virus infection of neuroglial cells may impair other neuroglial functions besides the production and maintenance of myelin. Consequently our increased understanding of the pathogenesis of progressive multifocal leukoencephalopathy suggests new ways to intervene in JC virus infection with immunomodulation therapies. Perhaps along with trials of nucleoside analogs or interferon administration, this fatal disease, for which no consensus of antiviral therapy exists, may yield to innovative treatment protocols.

Typing of human polyomavirus JC virus on the basis of restriction fragment length polymorphisms

JC virus DNA clones from the urine of nonimmunosuppressed Japanese individuals regularly contain an archetypal regulatory sequence which may have generated various regulatory sequences of JC virus isolates from patients with progressive multifocal leukoencephalopathy (PML). In this study, we established 15 new clones from the urine of Dutch, German, and Taiwanese healthy volunteers and patients. Most of these clones contained regulatory sequences essentially identical to the archetypal regulatory sequence. These clones, along with two representative urine-derived clones in Japan and five clones from the brains of PML patients (four established in the United States and one established in Japan), were analyzed with a number of restriction enzymes. We found nine restriction fragment length polymorphisms by which all clones were classified into either of the two types, A and B. Type A contained only clones from the West, while type B contained some from the West and all from eastern Asia. Each type contained both urine-derived and PML-derived clones. Furthermore, there was a close relationship between some urine-derived clones and some PML-derived clones in restriction site mapping analysis. These findings support the adaptation hypothesis which has been postulated to explain the genesis of PML-type JC viruses.

Enhancer/promoter activities of regulatory regions of representative JC virus isolates

The enhancer/promoter activities of JC virus isolates MAD1, MAD8, and MAD11 in HeLa cells and in human glial cells expressing either SV40 or JCV(MAD1) tumor antigens were significantly different from one another in each cell line.

BK virus and JC virus shed during pregnancy have predominantly archetypal regulatory regions

Twenty-three BK virus and JC virus DNA samples obtained from urine of pregnant women had almost exclusively archetypal transcriptional control regions. Rearrangements characteristic of laboratory strains are apparently not required for reactivation in humans. Unexpectedly, alignment shows that many elements identified previously in the BK virus enhancer are conserved in the JC virus archetype.

Sequence rearrangement in JC virus DNAs molecularly cloned from immunosuppressed renal transplant patients

From nonimmunocompromised individuals, we have recently identified a possible archetypal JC virus DNA sequence from which various regulatory sequences of JC virus isolates derived from patients with progressive multifocal leukoencephalopathy (PML) could have evolved. In this study, we analyzed the regulatory sequences of JCV DNAs cloned from urine samples of a PML risk group (renal transplant patients on immunosuppressive therapy). A number of JC virus DNAs were molecularly cloned from virions excreted in the urine of eight patients. Furthermore, fragments containing the regulatory region were amplified by the polymerase chain reaction and subsequently molecularly cloned from cell-associated JC virus excreted in the urine of two patients. The regulatory regions in all clones were analyzed with restriction enzymes, and those in representative clones were sequenced. We found that clones with the archetypal regulatory sequence were predominant in all urine samples, but a few clones carried regulatory sequences that diverged from the archetypal sequence by deletion or duplication. The finding that sequence rearrangement in the archetypal regulatory region occurs in the course of infection in immunosuppressed hosts is consistent with the adaptation hypothesis which has been put forward to explain the divergence of the regulatory regions in PML-derived JC virus isolates.

At least two types of control regions can be found among naturally occurring BK virus strains

The various strains of BK virus (BKV) exhibit a remarkable degree of heterogeneity in the transcriptional control region, which may affect the biological characteristics of a BKV strain. We describe the detection and sequencing of BKV control regions directly from urine samples and after propagation in cell culture. A BKV strain [BKV (TU)] with a control region anatomy not described earlier, as well as a BKV (WW)-like strain [BKV (WWT)], was detected in urine samples by direct sequencing of polymerase chain reaction products. Urine inocula containing BKV (WWT) yielded BKV (TU) upon one passage in cell culture, while BKV (TU) did not change its control region during propagation in cell culture. Analysis of the nucleotide sequence of the transcriptional control regions revealed a partial deletion and duplication in BKV (TU) compared with BKV (WWT). In addition, the control region of BKV (TU) contains two point mutations relative to BKV (WWT). This indicates that both virus strains were probably present in the BKV (WWT)-dominated urine inocula, rather than that BKV (WWT) genomes were rearranged into BKV (TU) genomes during cell propagation. The heterogeneity of the control region of BKV strains is discussed in relation to both confirmed and putative transcription factor-binding sites.

Isolation of a possible archetypal JC virus DNA sequence from nonimmunocompromised individuals

We molecularly cloned JC polyomavirus DNAs from urine samples of eight nonimmunosuppressed patients and two healthy individuals. The cloned viral DNAs all contained an archetypal regulatory sequence from which various regulatory sequences of JC polyomavirus isolates derived from patients with progressive multifocal leukoencephalopathy could have evolved by deletion and amplification.