JC virus viremia in interferon-beta -treated and untreated Italian multiple sclerosis patients and healthy controls

Ring-Enhancing Progressive Multifocal Leukoencephalopathy Mimicking Glioma in a Presumed Immunocompetent Patient With a History of Multiple Sclerosis: A Case Report and Review of the Literature

The differential diagnoses of ring-enhancing lesions of the brain parenchyma is broad, but complete ring-enhancing lesions often indicate a neoplastic or infectious process. We present a case of a 70-year-old female with a history of multiple sclerosis (MS) who was not on current disease-modifying therapy (DMT) and was found to have a ring-enhancing lesion that mimicked a high-grade glioma. The patient underwent gross total resection, and histopathologic and molecular analysis revealed a diagnosis of progressive multifocal leukoencephalopathy (PML). A subsequent medical workup on the patient was unrevealing aside from mild lymphopenia. This is a unique case that highlights both an unusual clinical presentation and radiographic appearance of PML. There is a known associated increased risk of PML with the use of some DMTs for MS. However, this case raises the question of the possibility of developing PML years after interferon beta-1a therapy in a patient without overt immunosuppression.

Interferon-β acts directly on T cells to prolong allograft survival by enhancing regulatory T cell induction through Foxp3 acetylation

Type I interferons (IFNs) are pleiotropic cytokines with potent antiviral properties that also promote protective T cell and humoral immunity. Paradoxically, type I IFNs, including the widely expressed IFNβ, also have immunosuppressive properties, including promoting persistent viral infections and treating T-cell-driven, remitting-relapsing multiple sclerosis. Although associative evidence suggests that IFNβ mediates these immunosuppressive effects by impacting regulatory T (Treg) cells, mechanistic links remain elusive. Here, we found that IFNβ enhanced graft survival in a Treg-cell-dependent murine transplant model. Genetic conditional deletion models revealed that the extended allograft survival was Treg cell-mediated and required IFNβ signaling on T cells. Using an in silico computational model and analysis of human immune cells, we found that IFNβ directly promoted Treg cell induction via STAT1- and P300-dependent Foxp3 acetylation. These findings identify a mechanistic connection between the immunosuppressive effects of IFNβ and Treg cells, with therapeutic implications for transplantation, autoimmunity, and malignancy.

COVID-19 and disease-modifying therapies in patients with demyelinating diseases of the central nervous system: A systematic review

Introduction

The Coronavirus disease-19 (COVID-19) pandemic continues to expand across the world. This pandemic has had a significant impact on patients with chronic diseases. Among patients with demyelinating diseases of the central nervous system (CNS), such as Multiple Sclerosis (MS) or Neuromyelitis Optica Spectrum Disorder (NMOSD), concerns remain about the potential impact of COVID-19 on these patients given their treatment with immunosuppressive or immunomodulatory therapies. In this study, we review the existing literature investigating the impact of disease-modifying therapies(DMT) on COVID-19 risks in this group of patients.

Method

For this systematic review, we searched PubMed from January 1, 2020, to December 3, 2020. The following keywords were used: “COVID-19” AND “Multiple Sclerosis” OR “Neuromyelitis Optica.” Articles evaluating COVID-19 in patients with demyelinating diseases of CNS were included. This study evaluates the different aspects of the DMTs in these patients during the COVID-19 era.

Results and conclusion

A total of 262 articles were found. After eliminating duplicates and unrelated research papers, a total of 84 articles met the final inclusion criteria in our study. Overall, the experiences of 2493 MS patients and 37 NMOSD patients with COVID-19 were included in this review. Among them, 46(1.8%) MS patients died(the global death-to-case ratio of Covid-19 was reported about 2.1%). Among DMTs, Rituximab had the highest mortality rate (4%). Despite controversies, especially concerning anti-CD20 monoclonal antibody therapies, a relation between DMT-use and COVID-19 disease- course was not found in many studies. This observation reinforces the recommendation of not stopping current DMTs. Other variables such as age, higher expanded disability status scale (EDSS) scores, cardiac comorbidities, and obesity were independent risk factors for severe COVID-19.

Despite the risks of infection, most patients were willing to continue their DMT during the pandemic because of more significant concern about the risk of relapse or worsening MS symptoms. After the infection, an immune response's attenuation was seen in the patients on Fingolimod and anti-CD20 monoclonal antibodies. This may be a critical finding in future vaccinations.

Inadequate Immune Humoral Response against JC Virus in Progressive Multifocal Leukoencephalopathy Non-Survivors

JC virus (JCV) causes progressive multifocal leukoencephalopathy (PML) in immunosuppressed patients. There is currently no effective specific antiviral treatment and PML management relies on immune restoration. Prognosis markers are crucially needed in this disease because of its high mortality rate. In this work, we investigated the compartmentalization of JCV strains as well as the humoral neutralizing response in various matrices to further understand the pathophysiology of PML and define markers of survival. Four patients were included, of which three died in the few months following PML onset. Cerebrospinal fluid (CSF) viral loads were the highest, with plasma samples having lower viral loads and urine samples being mostly negative. Whether at PML onset or during follow-up, neutralizing antibody (NAb) titers directed against the same autologous strain (genotype or mutant) were the highest in plasma, with CSF titers being on average 430-fold lower and urine titers 500-fold lower at the same timepoint. Plasma NAb titers against autologous genotype or mutant were lower in non-survivor patients, though no neutralization “blind spot” was observed. The surviving patient was followed up until nine months after PML onset and presented, at that time, an increase in neutralizing titers, from 38-fold against the autologous genotype to around 200-fold against PML mutants. Our results suggest that patients’ humoral neutralizing response against their autologous strain may play a role in PML outcome, with survivors developing high NAb titers in both plasma and CSF.

COVID-19 and MS disease-modifying therapies

OBJECTIVE

To address concerns regarding the effect of MS disease-modifying therapies (DMTs) on the expression of coronavirus 2019 (COVID-19).

METHODS

Review of the current state of knowledge regarding the viral etiology of COVID-19, mechanisms of injury by SARS-CoV-2 infection, and the effect of individual DMTs on the risk of infection and COVID-19 disease expression.

RESULTS

Although data are limited, MS DMTs do not obviously increase the risk of acquiring symptomatic SARS-CoV-2 infection. The severe morbidity and mortality of SARS-CoV-2 appear to be largely the consequence of an overly robust immune response rather than the consequence of unchecked viral replication. The effects of specific MS DMTs on the immune response that may increase the risk of impaired viral clearance and their potential counterbalancing beneficial effects on the development of COVID-19-associated acute respiratory distress syndrome are reviewed.

CONCLUSION

Although there is currently insufficient real-world experience to definitively answer the question of the effect of a specific MS DMT on COVID-19, registries presently in nascent form should provide these answers. This review provides an approach to addressing these concerns while the data are being accumulated. Early insights suggest that the risk of infection and associated morbidity of COVID-19 in this population is little different than that of the population at large.

Merkel cell polyomavirus DNA in the blood of patients with neurological diseases and healthy controls

Aim: Merkel cell polyomavirus (MCPyV) is the etiological agent of Merkel cell carcinoma. Its genome has been detected in anatomic districts from healthy and ill subjects. Data regarding the MCPyV DNAemia in neurological patients are lacking. Materials & methods: Blood was obtained from 129 neurological patients and 181 controls (HIV positive or negative). Real-time polymerase chain reaction (Q-PCR) was conducted to quantify MCPyV loads in blood specimens. Results: MCPyV DNA was detected in 17.1% of cases and 11.0% of controls in <1% of cells. No association between MCPyV DNA presence and HIV status was observed. Conclusion: Blood cells may be a reservoir for MCPyV. The presence of MCPyV genome in blood of healthy subjects might be relevant for transfusion medicine.

Progressive multi-focal leucoencephalopathy - driven from rarity to clinical mainstream by iatrogenic immunodeficiency

Advances in immune-mediated targeted therapies have proved to be a double-edged sword for patients by highlighting the risk of iatrogenic infective complications. This has been exemplified by progressive multi-focal leucoencephalopathy (PML), a hitherto rare devastating viral infection of the brain caused by the neurotrophic JC polyoma virus. While PML achieved prominence during the first two decades of the HIV epidemic, effective anti-retroviral treatment and restitution of T cell function has led to PML being less prominent in this population. HIV infection as a predisposing factor has now been supplanted by T cell immunodeficiency induced by a range of immune-mediated therapies as a major cause of PML. This review focuses on PML in the context of therapeutic immunosuppression and encompasses therapeutic monoclonal antibodies, novel immunomodulatory agents such as Fingolimod and dimethyl fumarate, as well as emerging data on PML in primary immune deficiency.

Classifying PML risk with disease modifying therapies

OBJECTIVE

To catalogue the risk of PML with the currently available disease modifying therapies (DMTs) for multiple sclerosis (MS).

BACKGROUND

All DMTs perturb the immune system in some fashion. Natalizumab, a highly effective DMT, has been associated with a significant risk of PML. Fingolimod and dimethyl fumarate have also been unquestionably associated with a risk of PML in the MS population. Concerns about PML risk with other DMTs have arisen due to their mechanism of action and pharmacological parallel to other agents with known PML risk. A method of contextualizing PML risk for DMTs is warranted.

METHODS

Classification of PML risk was predicated on three criteria:: 1) whether the underlying condition being treated predisposes to PML in the absence of the drug; 2) the latency from initiation of the drug to the development of PML; and 3) the frequency with which PML is observed.

RESULTS

Among the DMTs, natalizumab occupies a place of its own with respect to PML risk. Significantly lesser degrees of risk exist for fingolimod and dimethyl fumarate. Whether PML will be observed with other DMTs in use for MS, such as, rituximab, teriflunomide, and alemtuzumab, remains uncertain.

DISCUSSION

A logical classification for stratifying DMT PML risk is important for both the physician and patient in contextualizing risk/benefit ratios. As additional experience accumulates regarding PML and the DMTs, this early effort will undoubtedly require revisiting.

Treatment options for progressive multifocal leukoencephalopathy in HIV-infected persons: current status and future directions

Progressive multifocal encephalopathy (PML) caused by JC virus was frequently encountered in AIDS patients before combination antiretroviral therapy (cART). Incidence decreased and the outcome improved with cART. The immune reconstitution with cART is beneficial for HIV-infected patients and is an effective treatment for PML. However, when it is excessive an inflammatory response immune syndrome might occur with deterioration of PML. So far, no specific therapy has proven efficacious in small clinical trials in spite of some optimistic case reports. Combination of drugs targeted at different stages of JC virus life cycle seems to have a better effect. Passive and active immune therapies, immune competence "boosters" appear promising. New future approaches such as gene editing are not far away.

JC virus urinary excretion and seroprevalence in natalizumab-treated multiple sclerosis patients

The risk of developing progressive multifocal leukoencephalopathy (PML), as a consequence of infection/reactivation with JC virus (JCV), is consistent in natalizumab-treated multiple sclerosis (MS) patients, with 430 cases of PML reported so far. The risk of PML is higher in JCV seropositive patients, and it is recommended that only MS patients without JCV antibodies should be enrolled in the treatment postulating that they do not have JCV infection.We have studied forty-two natalizumab-treated MS patients, and urine and blood were collected monthly for up to 60 months. JCV and BK virus (BKV) DNA presence was verified using quantitative real-time PCR assays, and serum anti-JCV antibodies were measured with the Stratify and/or Stratify DxSelect tests.JCV and BKV DNA were not found in the blood samples, whereas they were found at least once in the urine of 21 of 42 (50 %) and of 25/42 (59.5 %) patients, respectively. JCV DNA urinary shedding increased up to month 24 of natalizumab treatment (45.2 %), and the effect of time was significant for JCV (p = 0.04), but not for BKV (p = 0.39). JCV viruria and seropositivity did not completely correlate, since three patients shedding JCV DNA in the urine were seronegative according to the serological tests.The results indicated that natalizumab therapy may increase the rate of JCV urinary shedding. Additionally, we confirmed that the identification of JCV carriers cannot solely rely on serological tests, but sensitive methods for viral DNA detection should be adopted to more precisely identify the truly JCV uninfected cases.

The human JC polyomavirus (JCPyV): virological background and clinical implications

JC polyomavirus (JCPyV) was the first of now 12 PyVs detected in humans, when in 1964, PyV particles were revealed by electron microscopy in progressive multifocal leukoencephalopathy (PML) tissues. JCPyV infection is common in 35-70% of the general population, and the virus thereafter persists in the renourinary tract. One third of healthy adults asymptomatically shed JCPyV at approximately 50,000 copies/mL urine. PML is rare having an incidence of <0.3 per 100,000 person years in the general population. This increased to 2.4 per 1000 person years in HIV-AIDS patients without combination antiretroviral therapy (cART). Recently, PML emerged in multiple sclerosis patients treated with natalizumab to 2.13 cases per 1000 patients. Natalizumab blocks α4-integrin-dependent lymphocyte homing to the brain suggesting that not the overall cellular immunodeficiency but local failure of brain immune surveillance is a pivotal factor for PML. Recovering JCPyV-specific immune control, e.g., by starting cART or discontinuing natalizumab, significantly improves PML survival, but is challenged by the immune reconstitution inflammatory syndrome. Important steps of PML pathogenesis are undefined, and antiviral therapies are lacking. New clues might come from molecular and functional profiling of JCPyV and PML pathology and comparison with other replicative pathologies such as granule cell neuronopathy and (meningo-)encephalitis, and non-replicative JCPyV pathology possibly contributing to some malignancies. Given the increasing number of immunologically vulnerable patients, a critical reappraisal of JCPyV infection, replication and disease seems warranted.

Weight cycling enhances adipose tissue inflammatory responses in male mice

Background

Obesity is associated with low-grade chronic inflammation attributed to dysregulated production, release of cytokines and adipokines and to dysregulated glucose-insulin homeostasis and dyslipidemia. Nutritional interventions such as dieting are often accompanied by repeated bouts of weight loss and regain, a phenomenon known as weight cycling (WC).

Methods

In this work we studied the effects of WC on the feed efficiency, blood lipids, carbohydrate metabolism, adiposity and inflammatory markers in C57BL/6 male mice that WC two or three consecutive times by alternation of a high-fat (HF) diet with standard chow (SC).

Results

The body mass (BM) grew up in each cycle of HF feeding, and decreased after each cycle of SC feeding. The alterations observed in the animals feeding HF diet in the oral glucose tolerance test, in blood lipids, and in serum and adipose tissue expression of adipokines were not recuperated after WC. Moreover, the longer the HF feeding was (two, four and six months), more severe the adiposity was. After three consecutive WC, less marked was the BM reduction during SC feeding, while more severe was the BM increase during HF feeding.

Conclusion

In conclusion, the results of the present study showed that both the HF diet and WC are relevant to BM evolution and fat pad remodeling in mice, with repercussion in blood lipids, homeostasis of glucose-insulin and adipokine levels. The simple reduction of the BM during a WC is not able to recover the high levels of adipokines in the serum and adipose tissue as well as the pro-inflammatory cytokines enhanced during a cycle of HF diet. These findings are significant because a milieu with altered adipokines in association with WC potentially aggravates the chronic inflammation attributed to dysregulated production and release of adipokines in mice.

Disease-modifying drugs for multiple sclerosis and JC virus expression

Natalizumab-associated progressive multifocal leukoencephalopathy in multiple sclerosis (MS) occurred in two individuals also treated with interferon β1a, raising concerns about the interaction of these disease-modifying agents and leading to the recommendation to avoid their concomitant administration. However, type I interferons are antiviral. Using a real-time quantitative polymerase chain reaction for the detection and quantification of the John Cunningham virus (JCV), DNA in peripheral blood mononuclear cells (PBMCs), and urine in MS patients, we tested the hypothesis that MS disease-modifying drugs (DMD) qualitatively and quantitatively alter JCV prevalence and viral copy numbers. Two hundred thirty-nine patients were enrolled in a cross-sectional study in which blood and urine specimens were collected at a single time and 37 newly diagnosed, treatment-naïve MS patients were enrolled in a longitudinal study in which specimens were obtained at diagnosis and 6 months after treatment initiation. JCV DNA was detected in PBMCs of only two patients (0.07 %), but was commonly detected in the urine (46.8 %) in this population. There was no effect of DMDs on blood or urinary JCV prevalence or viral copy numbers with either glatiramer acetate (Copaxone®) or interferon-β therapy (Avonex®, Betaseron®, or Rebif®). The small number of patients on other therapies precluded meaningful comment about their effects. No obvious effect of the platform DMDs on JCV prevalence was observed even for the interferon-βs.

Epstein-Barr virus stimulates torque teno virus replication: a possible relationship to multiple sclerosis

Viral infections have been implicated in the pathogenesis of multiple sclerosis. Epstein-Barr virus (EBV) has frequently been investigated as a possible candidate and torque teno virus (TTV) has also been discussed in this context. Nevertheless, mechanistic aspects remain unresolved. We report viral replication, as measured by genome amplification, as well as quantitative PCR of two TTV-HD14 isolates isolated from multiple sclerosis brain in a series of EBV-positive and -negative lymphoblastoid and Burkitt's lymphoma cell lines. Our results demonstrate the replication of both transfected TTV genomes up to day 21 post transfection in all the evaluated cell lines. Quantitative amplification indicates statistically significant enhanced TTV replication in the EBV-positive cell lines, including the EBV-converted BJAB line, in comparison to the EBV-negative Burkitt's lymphoma cell line BJAB. This suggests a helper effect of EBV infections in the replication of TTV. The present study provides information on a possible interaction of EBV and TTV in the etiology and progression of multiple sclerosis.

Progressive multifocal leukoencephalopathy and newer biological agents

Progressive multifocal leukoencephalopathy (PML) is a rare demyelinating disease of the brain due to a polyoma virus, JC virus. Despite the ubiquity of this virus, PML is rare and almost always seen in association with an underlying immunosuppressive condition. In the last 30 years, AIDS has been the most common predisposing factor. The observation of PML attending the use of certain monoclonal antibody therapies and other pharmacological agents has raised concerns about the safety profile of these agents, but has also provided a window into the pathogenesis of PML. Certain agents, such as the monoclonal antibodies natalizumab, an α4β1 and α4β7 integrin inhibitor, and efalizumab, an antibody directed against CD11a, appear to uniquely predispose to PML. Prior to their introduction for multiple sclerosis and Crohn's disease with respect to natalizumab, and psoriasis with respect to efalizumab, PML had never been observed with these disorders. PML occurring with other agents that currently carry US FDA-mandated 'black-box' warnings, such as rituximab, an antibody directed to CD20, or mycophenolate mofetil, a drug that inhibits T- and B-cell proliferation, typically occur in the background of underlying disorders that have already been identified as risks for PML. This review will focus on the available data regarding the risk for PML with monoclonal antibodies and other drugs. A biologically plausible explanation for the increased risk of PML will be proposed, as well as potential strategies for mitigating disease risk.

[Progressive multifocal leukoencephalopathy. Undesirable side effect of immunotherapy]

As new cases arise of progressive multifocal leukoencephalopathy (PML) in patients with multiple sclerosis (MS) treated with the monoclonal antibody natalizumab, a critical discussion about risks and advantages of this specific kind of immunotherapy appears necessary. Practical consequences and treatment options are addressed based on current concepts of PML's pathogenesis in patients treated with natalizumab. Critical patient selection based on risk:benefit considerations, limited therapy regimens, early diagnosis of PML by clinical and paraclinical criteria, and therapeutic perspectives for treating PML are discussed. The risk of PML in patients with MS needs to be continually monitored and should be reduced with all means available to ensure optimal outcome.

Monoclonal antibody-associated progressive multifocal leucoencephalopathy in patients treated with rituximab, natalizumab, and efalizumab: a Review from the Research on Adverse Drug Events and Reports (RADAR) Project

Progressive multifocal leucoencephalopathy (PML) is a serious and usually fatal CNS infection caused by JC polyoma virus. CD4+ and CD8+ T lymphopenia, resulting from HIV infection, chemotherapy, or immunosuppressive therapy, are the primary risk factors. The immune modulatory monoclonal antibodies rituximab, natalizumab, and efalizumab have received regulatory approval in the USA and Europe for treatment of non-Hodgkin lymphoma, rheumatoid arthritis, and chronic lymphocytic leukaemia (Europe only); multiple sclerosis and Crohn's disease; and psoriasis, respectively. Efalizumab and natalizumab administration is associated with CD4+ T lymphopenia and altered trafficking of T lymphocytes into the CNS, and rituximab leads to prolonged B-lymphocyte depletion. Unexpected cases of PML developing in people who receive these drugs have been reported, with many of the affected individuals dying from this disease. Herein, we review clinical findings, pathology, epidemiology, basic science, and risk-management issues associated with PML infection developing after treatment with these monoclonal antibodies.

Progressive multifocal leukoencephalopathy after rituximab therapy in HIV-negative patients: a report of 57 cases from the Research on Adverse Drug Events and Reports project

Rituximab improves outcomes for persons with lymphoproliferative disorders and is increasingly used to treat immune-mediated illnesses. Recent reports describe 2 patients with systemic lupus erythematosus and 1 with rheumatoid arthritis who developed progressive multifocal leukoencephalopathy (PML) after rituximab treatment. We reviewed PML case descriptions among patients treated with rituximab from the Food and Drug Administration, the manufacturer, physicians, and a literature review from 1997 to 2008. Overall, 52 patients with lymphoproliferative disorders, 2 patients with systemic lupus erythematosus, 1 patient with rheumatoid arthritis, 1 patient with an idiopathic autoimmune pancytopenia, and 1 patient with immune thrombocytopenia developed PML after treatment with rituximab and other agents. Other treatments included hematopoietic stem cell transplantation (7 patients), purine analogs (26 patients), or alkylating agents (39 patients). One patient with an autoimmune hemolytic anemia developed PML after treatment with corticosteroids and rituximab, and 1 patient with an autoimmune pancytopenia developed PML after treatment with corticosteroids, azathioprine, and rituximab. Median time from last rituximab dose to PML diagnosis was 5.5 months. Median time to death after PML diagnosis was 2.0 months. The case-fatality rate was 90%. Awareness is needed of the potential for PML among rituximab-treated persons.

Natalizumab in the treatment of multiple sclerosis

Natalizumab reduced the rate of clinical relapse at one year by 68% and the risk of sustained progression of disability by 42-54% over 2 years in its pivotal phase III trial (AFFIRM) in relapsing-remitting multiple sclerosis (RRMS). Natalizumab is generally well tolerated, but due to rare and potentially fatal side-effects, it was approved with a restricted-distribution format in 2006. Expert statements and the European Medical Agency recommend the use of natalizumab after failure of first-line disease-modifying therapies in patients with relapsing forms of MS. As part of the risk management plan, worldwide extensive safety programmes aim to provide more data on natalizumab safety in clinical practice. At the end of September 2008, 48 000 patients have received natalizumab and 18000 patients are on treatment for at least 1 year. The assessment of risk and benefit is still ongoing.

Analysis of cerebrospinal fluid and cerebrospinal fluid cells from patients with multiple sclerosis for detection of JC virus DNA

OBJECTIVE

1) To determine whether JC virus (JCV) DNA was present in the cerebrospinal fluid (CSF) and blood from patients with multiple sclerosis (MS) in comparison with controls and 2) to find out if our clinical material, based on presence of JCV DNA, included any patient at risk for progressive multifocal leukoencephalopathy (PML).

METHODS

The prevalence of JCV DNA was analyzed in CSF and plasma from 217 patients with MS, 86 patients with clinically isolated syndrome (CIS), and 212 patients with other neurological diseases (OND). In addition, we analyzed CSF cells, the first report of JCV DNA in CSF cells in a single sample, and peripheral blood cells in a subgroup of MS (n = 49), CIS (n = 14) and OND (n = 53).

RESULTS

A low copy number of JCV DNA was detected in one MS cell free CSF sample and in one MS CSF cell samples. None of these had any signs of PML or developed this disease during follow-up. In addition, two OND plasma samples were JCV DNA positive, whereas all the other samples had no detectable virus.

CONCLUSION

A low copy number of JCV DNA may occasionally be observed both in MS and other diseases and may occur as part of the normal biology of JC virus in humans. This study does not support the hypothesis that patients with MS would be at increased risk to develop PML, and consequently screening of CSF as a measurable risk for PML is not useful.

Update on PML: lessons from the HIV uninfected and new insights in pathogenesis and treatment

Significant advances in our understanding of progressive multifocal leukoencephalopathy (PML) and its causative agent, JC virus, have been made since PML was first described 50 years ago. However, immune reconstitution remains the only proven, effective therapy in this devastating central nervous system disorder. Early diagnosis and adjustments of immune suppressants and modulator agents are critical in managing PML in HIV-negative patients. This review summarizes recent advances in our understanding of PML in HIV-uninfected patients in oncology, rheumatology, organ transplantation, and idiopathic immune deficiency and in association with novel therapeutics. Brain MRI data from our case series of brain biopsy-proven HIV-negative PML patients indicate the presence of an inflammatory/immune reaction in brain tissues, which was confirmed by immunocytologic analysis. Future studies to better understand PML pathogenesis in HIV-negative individuals may help uncover new potential therapeutic targets and improve PML outcomes.

Interferon beta1-a and selective anti-5HT(2a) receptor antagonists inhibit infection of human glial cells by JC virus

JC virus (JCV) is the causative agent of progressive multifocal leukoenchaphalopathy (PML). The disease develops when JCV gains access to the central nervous system, infects and destroys oligodendrocytes. The disease is rapidly progressing, typically fatal and no effective therapies exist to treat or prevent PML. The recent occurrence of PML in multiple sclerosis patients being treated with Avonex (IFNbeta1-a) and Tysabri (Natalizumab) and the recent reports linking JCV infection to the 5HT(2a) serotonin receptor led us to evaluate the effects of IFNbeta1-a and a panel of 5HT(2a) receptor antagonists for their ability to modulate virus infection. IFNbeta1-a was found to be a potent inhibitor of both virus infection and viral early and late gene expression. In addition, several 5HT(2a) receptor antagonists inhibited initial infection of cells by JCV but were less effective at reducing viral loads in an already established infection.