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

JCV detection in multiple sclerosis patients treated with natalizumab

Natalizumab therapy is associated with an increased risk of progressive multifocal leukoencephalopathy (PML). Because the prognosis of established PML is uniformly dismal, identification of highly susceptible patients to the disease may improve outcomes. We wanted to investigate whether serial plasma and cerebrospinal fluid (CSF) screening for polyomavirus would identify patients with laboratory evidence of viral infection prior to the development of clinical PML. Two hundred MS patients had pre-treatment CSF/plasma screening for JC virus (JCV) and BK virus (BKV) DNA, and thereafter every six treatments of natalizumab. In all positive patients treatment is stopped (due to potential risk of PML), they have follow-up clinical examinations and plasma/CSF JCV/BKV tests until all evaluations are normal. No patient developed clinical evidence of PML. Eight of the 200 patients had detectable JCV or BKV DNA. Five patients were positive for BKV DNA in the CSF and three patients were positive for JCV DNA (one in plasma, two in CSF). After cessation of natalizumab treatment, all patients converted to undetectable viral DNA. Screening for JCV in CSF in natalizumab-treated patients could help identify those at heightened risk for developing PML and discontinuing treatment in these patients may abort development of the clinical illness.

Mesothelioma mortality in Europe: impact of asbestos consumption and simian virus 40

Background

It is well established that asbestos is the most important cause of mesothelioma. The role of simian virus 40 (SV40) in mesothelioma development, on the other hand, remains controversial. This potential human oncogene has been introduced into various populations through contaminated polio vaccines. The aim of this study was to investigate whether the possible presence of SV40 in various European countries, as indicated either by molecular genetic evidence or previous exposure to SV40-contaminated vaccines, had any effect on pleural cancer rates in the respective countries.

Methods

We conducted a Medline search that covered the period from January 1969 to August 2005 for reports on the detection of SV40 DNA in human tissue samples. In addition, we collected all available information about the types of polio vaccines that had been used in these European countries and their SV40 contamination status.

Results

Our ecological analysis confirms that pleural cancer mortality in males, but not in females, correlates with the extent of asbestos exposure 25 – 30 years earlier. In contrast, neither the presence of SV40 DNA in tumor samples nor a previous vaccination exposure had any detectable influence on the cancer mortality rate in neither in males (asbestos-corrected rates) nor in females.

Conclusion

Using the currently existing data on SV40 prevalence, no association between SV40 prevalence and asbestos-corrected male pleural cancer can be demonstrated.

Immunoglobulin G, A, and M responses to BK virus in renal transplantation

Immunoglobulin G (IgG), IgA, and IgM antibodies were measured in serum samples from 71 organ donors, 81 kidney transplant recipients at transplantation, and 67 patients during the posttransplant period by using a virus-like particle-based enzyme-linked immunosorbent assay (ELISA). BK virus (BKV) and JC virus DNA were detected in urine and plasma by real-time PCR. IgG antibodies to BKV were demonstrated in the majority (80.3 to 100%) of patients irrespective of clinical category, but titers were highest in patients with active viral replication. IgA antibodies were present with greater frequency (72.7 to 81.3% versus 0 to 23.6%; P < 0.001) and higher titer (mean optical density, 0.11 to 0.15 versus 0.05 to 0.08; P < 0.001) in patients who were BKV DNA positive than those who were BKV DNA negative. IgM antibodies showed a similar pattern of reactivity but lower frequency in the setting of active viral replication (9.1 to 43.7% versus 0 to 1.4%; P < 0.001). A rise in IgG level of >0.577 optical density (OD) units or a rise in IgA or IgM level of >0.041 OD units was strongly associated with active viral replication. Urine viral load showed a positive correlation with IgM titer (r = 0.22) but a negative correlation with IgG titer (r = -0.28) and IgA titer (r = -0.1). Chronic dialysis patients typically did not have serologic or virologic evidence of active BKV infection. Anti-BKV titers did not rise in patients with JC viruria. In conclusion, measurement of anti-BKV antibody titer and class response can be used to detect the onset of viral replication. ELISAs can be quite specific despite considerable sequence homology between BK virus and JC virus.

A comparative study of BK and JC virus infections in organ transplant recipients

JC virus (JCV) rarely causes kidney disease, whereas BK virus (BKV) is a known cause of viral nephropathy. Existing studies on prevalence of JCV in healthy and transplanted subjects have reported only qualitative detection of viral DNA. We used quantitative PCR (qPCR) to assess JC viral load in transplant recipients and non-immunosuppressed controls, and compared JCV loads to BKV loads. JC viruria was seen in 8/23 (34.7%) controls, 23/103 (22.3%) renal, and 10/44 (22.7%) liver transplant patients. No patient developed JC viremia. BK viruria was seen in 2/23 (8.7%) controls, 36/103 (34.9%) renal, and 7/44 (15.9%) liver transplant patients. BK viremia was seen only in the kidney (8/103 = 7.7%) patients. The mean BKV urinary load was higher in kidney compared to liver patients and controls (4.22E + 07 vs. 2.88E + 05 vs. 4.39E + 02 copies/ml), whereas JC viral load was similar for all three patient groups (1.55E + 06 vs. 2.66E + 06 vs. 2.13E + 06 copies/ml). JCV viral loads were surprisingly high in all patient categories studied, but did not result in viremia or viral nephropathy. Although both BKV and JCV are widely latent in patients accepted for transplantation, concurrent reactivation of both viruses was infrequent. BKV viremia was seen in kidney but not liver recipients. The mechanisms underlying these notable phenomena remain to be investigated.

Hemorrhagic Cystitis in Children Undergoing Bone Marrow Transplantation: A Putative Role for Simian Virus 40

BACKGROUND

Late-onset hemorrhagic cystitis (HC) is a well-known severe complication of bone marrow transplantation (BMT), both in adults and in children. Protracted postengraftment HC is associated with graft-versus-host disease and viral infections, mainly caused by BK virus (BKV) or adenovirus (AV). This study investigated whether simian virus 40 (SV40) DNA sequences can be detected in specimens from pediatric patients affected by severe postengraftment HC.

METHODS

The clinical diagnosis of HC was made in 7 of 28 BMT children. DNA from peripheral blood mononuclear cells (PBMC) and urine sediment cells and supernatants was analyzed by polymerase chain reaction (PCR) for human cytomegalovirus (HCMV), AV, BKV, JC virus (JCV), and SV40. DNA filter hybridization and sequencing was carried out in SV40-positive samples.

RESULTS

SV40 footprints were detected in two of seven cases of HC. Specific SV40 DNA sequences were detected by PCR and by filter hybridization both in urine and in PBMC samples at the HC onset and during the follow-up. The DNA sequencing proved that the amplicons belonged to the SV40 wild-type. Urine samples of the two HC cases tested negative by cell cultures, PCR, or both for HCMV, BKV, JCV, and AV.

CONCLUSIONS

The detection of SV40 DNA sequences suggest that this simian polyomavirus could be involved, at least in some cases, in the HC occurring in children after BMT.

Progressive Multifocal Leukoencephalopathy

Progressive multifocal leukoencephalopathy is a subacute demyelinating disease that occurs in patients with defects in cell-mediated immunity, including those with AIDS and lymphoproliferative disorders. It is caused by reactivation of JC virus (JCV), which infects 70% to 90% of the population by adulthood, but remains latent in normal hosts. Once reactivated, JCV infects oligodendrocytes and astrocytes, with resultant cell lysis, leading to focal areas of demyelination and necrosis in cerebral white matter causing focal neurologic deficits and characteristic findings on MRI. Polymerase chain reaction for the detection of JCV is a sensitive and specific test, replacing brain biopsy as the initial diagnostic test in the appropriate clinical setting. Historically, the prognosis of progressive multifocal leukoencephalopathy is poor, with most patients dying within 6 months of diagnosis. Antiviral medications targeted against JCV have shown little success. However, with the use of highly active antiretroviral therapy, survival of AIDS patients with progressive multifocal leukoencephalopathy has improved.

Bk virus: a clinical review

We present a review of the clinically oriented literature about BK virus, a relative of JC virus, which is the etiologic agent of progressive multifocal leukoencephalopathy (PML). The kidney, lung, eye, liver, and brain have been proposed as sites of BK virus-associated disease, both primary and reactivated. BK virus has also been detected in tissue specimens from a variety of neoplasms. We believe that BK virus is most often permissively present in sites of disease in immunosuppressed patients, rather than being an etiologic agent that causes symptoms or pathologic findings. There is, however, strong evidence for BK virus-associated hemorrhagic cystitis and nephritis, especially in recipients of solid organ or bone marrow transplants. Now that BK virus can be identified by use of specific and sensitive techniques, careful evaluation of the clinical and pathologic presentations of patients with BK virus will allow us to form a clearer picture of viral-associated pathophysiology in many organ systems.

Does SV40 infection contribute to the development of human cancers?

A large number of recent studies have reported the detection of simian virus 40 (SV40) nucleotide sequences in a number of unrelated human cancers which include paediatric and adult brain tumours, pleural mesotheliomas, bronchopulmonary carcinomas and osteosarcomas. Most of the data have been gathered by the use of PCR assays. These observations imply that SV40 is circulating in human communities by person-to-person transmission and that the virus is capable of wide dissemination in the infected individual. These claims must be regarded with skepticism for a variety of reasons. There are several inconsistencies in the reported data; for example, there is a wide variation (0-23%) in the frequency of SV40 sequences in normal tissues. The results of PCR assays have been difficult to confirm by less error-prone and independent assays and the relationship of the virus to the tumour cell is not characterised. The SV40 sequences reported from humans are essentially identical to those of wild-type SV40; it is difficult to conceive that a highly species-specific polyomavirus like SV40 would cross the species barrier, become a human infection, and acquire pathogenic potential for the new host without significant adaptive change in its genome. The available evidence, although not extensive, does not indicate that SV40 is circulating in human communities. It is premature to discuss or speculate on the potential role of SV40 in the development of human cancer until the presence of SV40 in cancers and in human communities is established unequivocally, the risk factors for SV40 infection are elucidated, and the effect of SV40 exposure on the development of specific cancers is examined in the context of other known risk factors for those cancers.

JC and BK virus sequences are not detectable in leukaemic samples from children with common acute lymphoblastic leukaemia

Epidemiological evidence suggests that childhood leukaemia, and possibly common acute lymphoblastic leukaemia in particular, may have an infectious aetiology. Smith (1997 J Immunother 20: 89-100) recently suggested that the critical infectious event occurs during pregnancy, and identified the polyoma virus JC as a candidate agent. In the present study we investigated whether genomes from the JC virus, and closely related BK virus, could be detected in leukaemic cells. No positive results were obtained suggesting that JC virus is unlikely to play a direct role in leukaemogenesis.

Multiplex polymerase chain reaction for the simultaneous detection and typing of polyomavirus JC, BK and SV40 DNA in clinical samples

A novel multiplex nested PCR (nPCR) method was developed for detecting and differentiating simultaneously the DNA of polyomaviruses JC, BK and SV40 in a single tube. In the first amplification step the same set of primers were used to amplify a conserved DNA region of the large T antigen gene of JCV, BKV and SV40. The second round of multiplex nPCR was carried out using a set of primers designed to render products of different size for each related virus. The thermocycling parameters and concentration of each reaction component were optimised systematically to achieve optimal specificity and sensitivity for the nPCR assay. The sensitivity of the method ranged between one and 10 copies of polyomavirus genome. Cerebrospinal fluid (CSF) was examined from AIDS patients with clinical and neuroradiological evidence of progressive multifocal leukoencephalopathy (PML) and CSF from AIDS patients with other neurological alterations. Urine specimens from bone marrow transplant recipients affected by haemorrhagic cystitis were also tested. The results obtained suggest that the assay is a good tool for supporting the diagnosis of polyomavirus infection and could be used for epidemiological purposes and in other studies in order to define better the role of polyomaviruses in human disease.

Magnetic resonance imaging, thallium-201 SPET scanning, and laboratory analyses for discrimination of cerebral lymphoma and toxoplasmosis in AIDS

OBJECTIVES

To compare the results of magnetic resonance imaging (MRI) and thallium-201 (201Tl) SPET scanning with laboratory analyses including CSF DNA detection, brain biopsy, and necropsy in the discrimination of cerebral lymphoma and toxoplasmosis in patients with AIDS.

METHODS

A retrospective study of 32 patients infected with HIV who had focal CNS lesions on MRI as a result of either lymphoma or toxoplasmosis.

RESULTS

18 patients had lymphoma, 12 had toxoplasmosis, and two had both. Toxoplasma IgG antibodies were detected in only seven patients--four with toxoplasmosis, two with lymphoma, and one with both diagnoses. Epstein-Barr virus DNA was detected in CSF of all six patients with lymphoma and none of two with toxoplasmosis. MRI showed multiple lesions in 23 patients, appearances did not discriminate between lymphoma and toxoplasmosis; nine patients had single lesions, of these eight had lymphoma (p = 0.044, two tailed Fisher's exact test) 201Tl SPET showed accumulation in 17 with lymphoma and six with toxoplasmosis (p = 0.034, two tailed Fisher's exact test). Of nine patients with single lesions on MRI and 201Tl SPET with focal accumulation eight had lymphoma. 201Tl SPET uptake ratios of > or = 2.9 were only seen with lymphoma.

CONCLUSION

Knowledge of patients' toxoplasma serostatus does not aid discrimination between lymphoma and toxoplasmosis. Single lesions on MRI with focal accumulation of 201Tl strongly suggest lymphoma. Multiple lesions on MRI with 201Tl SPET uptake ratios > or = 2.9 also suggest lymphoma; uptake ratios less than 2.1 do not aid discrimination. Detection of Epstein-Barr virus DNA in CSF is highly sensitive and specific for cerebral lymphoma.

Comparison of magnetic resonance imaging with neuropathological findings in the diagnosis of HIV and CMV associated CNS disease in AIDS

OBJECTIVES

To compare the results of clinical assessment and MRI with neuropathological findings in the diagnosis of HIV and cytomegalovirus (CMV) associated CNS disease.

METHODS

A retrospective study of 35 patients infected with HIV who were examined at necropsy between four and 70 (median 20) days after neurological assessment and MRI.

RESULTS

Of the 35 patients, 19 had diffuse white matter hyperintensity on T2 weighted MRI, six of whom also had focal lesions. Nine other patients had focal white matter lesions and seven had changes in cortical atrophy only. Necropsy in the 19 with diffuse white matter hyperintensity showed HIV leukoencephalopathy (HIVLEP) with encephalitis in 10, CMV encephalitis in three, both HIVLEP/HIV encephalitis and CMV encephalitis in one, lymphoma in three, and non-specific inflammation in two. Necropsy in the 16 other patients without diffuse white matter hyperintensity showed CMV encephalitis in six, HIV encephalitis (without HIVLEP) in two, CMV encephalitis and HIVLEP/HIV encephalitis in one, non-HIV associated abnormalities in five, herpes simplex encephalitis in one, and lymphoma in one. CMV DNA was detected in CSF of five of seven patients with CMV encephalitis and in two of two with CMV associated polyradiculopathy but without CMV encephalitis. Diffuse white matter hyperintensity on MRI had a sensitivity of 100%, a specificity of 66.6%, and a positive predictive value of 58% for diagnosis of HIVLEP.

CONCLUSION

Diffuse white matter hyperintensity on MRI can be due to either HIV or CMV associated pathology or non-specific abnormalities.