JC polyomavirus expression and bell-shaped regulation of its SF2/ASF suppressor during the follow-up of multiple sclerosis patients treated with natalizumab

Natalizumab is effective against multiple sclerosis (MS), but is associated with progressive multifocal leukoencephalopathy (PML), fatal disease caused by the JCV polyomavirus. The SF2/ASF (splicing factor2/alternative splicing factor) inhibits JCV in glial cells. We wondered about SF2/ASF modulation in the blood of natalizumab-treated patients and if this could influence JCV reactivation. Therefore, we performed a longitudinal study of MS patients under natalizumab, in comparison to patients under fingolimod and to healthy blood donors. Blood samples were collected at time intervals. The expression of SF2/ASF and the presence and expression of JCV in PBMC were analyzed. A bell-shaped regulation of SF2/ASF was observed in patients treated with natalizumab, increased in the first year of therapy, and reduced in the second one, while slightly changed, if any, in patients under fingolimod. Notably, SF2/ASF was up-regulated, during the first year, only in JCV DNA-positive patients, or with high anti-JCV antibody response; the expression of the JCV T-Ag protein in circulating B cells was inversely related to SF2/ASF protein expression. The SF2/ASF reduction, parallel to JCV activation, during the second year of therapy with natalizumab, but not with fingolimod, may help explain the increased risk of PML after the second year of treatment with natalizumab, but not with fingolimod. We propose that SF2/ASF has a protective role against JCV reactivation in MS patients. This study suggests new markers of disease behavior and, possibly, help in re-evaluations of therapy protocols.     

Risk stratification for progressive multifocal leukoencephalopathy in patients treated with natalizumab

Natalizumab is a highly effective immunomodulator in the treatment of multiple sclerosis (MS). Treatment with natalizumab has been associated with progressive multifocal leukoencephalopathy (PML), an infection of the central nervous system (CNS) caused by a pathogenic form of the normally benign JC virus (JCV). We searched PubMed and used current data from the natalizumab global safety database to assess risk factors and quantify the risk of PML. Natalizumab treatment duration and prior use of immunosuppressive therapies are established risk factors for development of PML in natalizumab-treated patients. With the development of a reliable and validated assay for detection of antibodies in patients with MS directed against JCV, it is now possible to identify persons who are carriers of JCV. The availability of this assay provides an additional option for risk stratification of PML in patients using or considering natalizumab therapy. Recommendations for clinical management of patients with MS and use of natalizumab are provided based on the presence of these three risk factors. The identification of risk factors that increase the likelihood of PML in natalizumab-treated patients can facilitate benefit-risk discussions between health care professionals and patients. Continued research and data collection will further develop our understanding of PML and the mechanisms by which these risk factors contribute to its development.     

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.     

Progressive multifocal leukoencephalopathy: a review of the neuroimaging features and differential diagnosis

Progressive multifocal leukoencephalopathy (PML) is an uncommon and often fatal demyelinating disease of human central nervous system, which is caused by reactivation of the polyomavirus JC (JCV). PML generally occurs in patients with profound immunosuppression such as AIDS patients. Recently, a number of PML cases have been associated with administration of natalizumab for treatment of multiple sclerosis (MS) patients. Diagnosis and management of PML became a major concern after its occurrence in multiple sclerosis patients treated with natalizumab. Diagnosis of PML usually rests on neuroimaging in the appropriate clinical context and is further confirmed by cerebrospinal fluid polymerase chain reaction (PCR) for JCV DNA. Treatment with antiretroviral therapies in HIV-seropositive patients or discontinuing natalizumab in MS patients with PML may lead to the development of immune reconstitution inflammatory syndrome (IRIS) which presents with deterioration of the previous symptoms and may lead to death. In patients under treatment with monoclonal antibodies in routine practice, or new ones in ongoing clinical trials, differentiating PML from new MS lesions on brain MRI is critical for both the neurologists and neuroradiologists. In this review, we discuss the clinical features, neuroimaging manifestations of PML, IRIS and neuroimaging clues to differentiate new MS lesions from PML. In addition, various neuroimaging features of PML on the non-conventional MR techniques such as diffusion-weighted imaging (DWI), diffusion tensor imaging (DTI), and MR spectroscopy (MRS) are discussed.     

Anti-JCV antibody prevalence in a French cohort of MS patients under natalizumab therapy

To measure the prevalence of JCV-specific antibodies in a French cohort of MS patients treated with natalizumab and to identify risk factor(s) of JCV seropositivity. Progressive multifocal leukoencephalopathy (PML) risk may be stratified by anti-JCV antibody status, duration of natalizumab therapy (≥24?months) and prior exposure to immunosuppressive (IS) drugs. No data are available in France on the prevalence of anti-JCV antibodies and distribution of PML risk factors in patients treated with natalizumab. Sera of 361 patients under natalizumab therapy in two MS centers were analyzed using a previously validated ELISA test. We studied different characteristics: demographic, ethnic, radiological, clinical, prior use of immunomodulatory (IM) or IS drugs and natalizumab exposure duration. The JCV seropositivity rate was 51?% for the whole cohort. Mean natalizumab exposure duration was 27.27?months?±?15.57 (mean?±?SD), and prior use of IS drugs was observed in 15.24?% of patients. Twenty-three patients (6.4?%) presented the three PML risk factors. By multivariate analysis, presence of anti-JCV antibodies was significantly linked to age, North African origin and natalizumab exposure duration. Anti-JCV antibody prevalence was similar to previously published data. Anti-JCV antibody status was linked to age. We also suggested that anti-JCV antibody status could be linked to natalizumab exposure duration and ethnic characteristics.     

JC virus granule cell neuronopathy: A novel clinical syndrome distinct from progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) typically affects the CNS white matter of the central nervous system. We present an human immunodeficiency virus-infected patient with polyomavirus JC infection restricted to granule cell neurons of the cerebellum and with corresponding neurological symptomatology. Magnetic resonance imaging demonstrated cerebellar atrophy without white matter lesions and stereotactic biopsy showed selective infection of the cerebellar granular cell layer, with preservation of Purkinje cells and absence of classic progressive multifocal leukoencephalopathy histopathology in underlying white matter. Evolution over 8 years was marked by symptomatic improvement corresponding to highly active antiretroviral therapy (HAART), with modest increase in CD4(+) T-cell counts. We propose to call this novel syndrome JCV granule cell neuronopathy (JCV GCN).     

Natalizumab therapy is associated with changes in serum JC virus antibody indices over time

To examine changes in anti-JC Virus (JCV) index measurements over time in multiple sclerosis (MS) patients to better understand this test, which is used in assessing risk of progressive multifocal leukoencephalopathy (PML) with natalizumab. We aim to describe and compare seroconversion rates, variability of JCV antibody index values, and changes in index values over time between patients on natalizumab therapy and patients naïve to natalizumab. Anti-JCV index values are used to help decide whether to start, continue, or stop treatment. Assessing how index values vary over time is interpreted to allow a patient’s risk of PML to be better characterized. Retrospective analysis was conducted using records of patients with multiple JCV antibody index measurements exposed to therapy with natalizumab (N = 150) or not (N = 145). Rates of seroconversion, variability of indices, and changes in index values over time were calculated and compared. Patients on natalizumab who were initially JCV antibody negative seroconverted at a significantly higher rate than patients naïve to natalizumab (23.9 vs. 9.1%, p < 0.01). Variability of anti-JCV indices was also found to be significantly higher for patients on natalizumab (p < 0.05). Patients on natalizumab additionally trended towards a larger increase in index values over time. Therapy with natalizumab was associated with higher rates of seroconversion and greater anti-JCV index variability, suggesting that therapy with natalizumab may influence this test used to assess risk of treatment with it.     

Spinal cord lesions of progressive multifocal leukoencephalopathy in an acquired immunodeficiency syndrome patient

Progressive multifocal leukoencephalopathy (PML) is a deadly demyelinating disease of the central nervous system, which occurs in immunosuppressed individuals. This disease is caused by a reactivation of the polyomavirus JC (JCV). Clinical presentation can be variable from patient to patient as lesions can occur anywhere in the CNS white matter; however, they appear to spare the optic nerves and the spinal cord. The authors present a case of PML in the setting of acquired immunodeficiency syndrome (AIDS) who developed PML lesions in the spinal cord, discovered during the postmortem examination. This finding is significant because PML has recently been diagnosed in patients with multiple sclerosis (MS) treated with the novel immunomodulatory medication natalizumab. Indeed, spinal cord lesions are frequent in MS. Therefore clinicians should be aware that in addition to the brain, PML may also affect the spinal cord white matter.     

Natalizumab discontinuation after PML risk stratification: outcome from a shared and informed decision

Multifocal progressive leukoencephalopathy (PML) is associated with JC virus (JCV) seropositivity, past immunosuppression, and natalizumab treatment for two years or more. The aim of our study was to investigate the rate of treatment discontinuation after stratifying for the three risk factors in a group of 104 natalizumab-treated patients with relapsing-remitting multiple sclerosis. We investigated JCV serological status in our population. We then divided patients into groups according to their PML risk. Treatment indication was reassessed. Of the patients, 64 (61.5%) were JCV seropositive. Amongst seropositive patients on natalizumab for 2 years or more, 10 had received immunosuppression (group A), and 38 had not (group B). After an informed and shared decision-making process, 6/10 (60%) from group A compared with 9/38 (23.7%) from group B discontinued treatment (p=0.027). In groups A and B, discontinuation also depended upon doctors' views (p=0.019, group A; p=0.010, group B) and clinical outcomes (p=0.021, group A). No-one from low-intermediate risk groups discontinued. The decision to discontinue natalizumab treatment is complex, even when clear PML risk rates are described. Clinical outcomes and doctors' idiosyncrasies play a crucial part in patients' final choice.     

Natalizumab dosage suspension: Are we helping or hurting?

The risk of developing progressive multifocal leukoencephalopathy increases with the duration of treatment with natalizumab. Planned dosage interruptions have been proposed as a means of decreasing cumulative risk. The clinical consequences of dosage interruption were evaluated in a single center cohort of natalizumab‐treated patients. Medical records were reviewed for 84 patients identified with multiple sclerosis who received 12 or more infusions of natalizumab at an academic multiple sclerosis center. Eighty‐one percent (68/84) underwent a dosage interruption, and 19% (16/84) had no interruption in natalizumab treatment. Of those with a treatment interruption, 27.9% (19/68) experienced a clinical relapse within 6 months of the suspension, whereas none of the patients with ongoing treatment experienced a flare during months 12 to 18 of treatment (p = 0.017, Fisher exact test). Survival analysis showed that Kaplan‐Meier curves comparing dosage interruption to ongoing treatment diverged (p = 0.025). Median time from treatment interruption to relapse onset was 3 months. No clinical predictors associated with an increased risk of developing flares during dosage interruption were identified. Among the 19 patients who had a flare, 7 had severe flares, with a mean number of 16 Gad+ lesions on brain magnetic resonance imaging (range, 6–40). Their median Expanded Disability Status Scale at natalizumab interruption was 3.0 and increased to 6.0 during the flare (p = 0.0008). Natalizumab dosage interruption is associated with clinical flares and return of radiographic inflammatory disease activity. Some of these flares can be clinically severe, with a high number of contrast‐enhanced lesions, suggesting a possible rebound of disease activity. Ann Neurol 2010;68:395–399     

Pulse monthly steroids during an elective interruption of natalizumab: a post-marketing study

Background and purpose: Temporary discontinuation of natalizumab is sometimes considered as the observed risk of progressive multifocal leukoencephalopathy (PML) in patients with multiple sclerosis (MS). However, interruption of natalizumab may result in a re‐start of disease activity. Methods: In this prospective post‐marketing study, 23 patients with MS treated with natalizumab elected a trial of treatment interruption (90–150 days) because of safety concerns on the risk of developing PML. To reduce the risk of disease activity return, patients received monthly intravenous (i.v.) steroid pulses before natalizumab re‐start. Results: Despite the steroid coverage, seven patients (30.4%) had an active scan during the natalizumab interruption period; of these, four also had a concomitant clinical exacerbation. Conclusions: Our findings suggest that i.v. steroids are not currently recommendable as drug coverage during a scheduled treatment interruption period.     

JC virus granular neuronopathy and rhombencephalic progressive multifocal leukoencephalopathy: Case report and review of the literature

JC virus (JCV) granular neuronopathy remains an under‐appreciated phenomenon whereby JCV inhabits neurons in the granular layer of the cerebellum causing neuronal loss, gliosis and a clinical cerebellar syndrome. The following case describes a man with sarcoidosis and idiopathic leukopenia who developed a clinical cerebellar syndrome due to JCV granular neuronopathy, followed by neurological decline due to rhombencephalic progressive multifocal leukoencephalopathy. This case reminds us of the ability of JCV to produce dual neuropathology which includes JCV granular neuronopathy, and the pathogenesis and clinical implications for this phenomenon are discussed.     

Central nervous system involvement in patients with monoclonal gammopathy and polyneuropathy

Background and purpose: To evaluate clinical presentation of patients with the clinical triad of monoclonal gammopathy, polyneuropathy and signs of CNS involvement. Methods: Nineteen patients with monoclonal protein (M‐protein, 9 IgM, 10 IgG) were studied. Clinical examination, MRI, cerebrospinal fluid analysis and immune reactivity against myelin‐associated glycoprotein and gangliosides in serum were obtained. By immunohistochemistry, different binding patterns of M‐proteins to human CNS tissue were investigated. Results: Nine out of 19 patients (four IgM, five IgG) showed one or more clinical signs of CNS involvement. Clinical features associated with signs of CNS pathology were disease duration and greater concentration of IgM paraprotein. The IgM M‐protein of two patients strongly stained the cortex/cerebellar neurons in human brain sections. Conclusion: Our results complement previous reports that some patients with monoclonal gammopathy and polyneuropathy can develop solitary or disseminated signs of CNS involvement. It indicates that pathological effects of M‐proteins are not necessarily restricted to the peripheral nervous system. The specificity and affinity of circulating M‐protein to antigens in the CNS might be critical for the development of different clinical phenotypes.     

Productive infection of cerebellar granule cell neurons by JC virus in an HIV+ individual

BACKGROUND: In the setting of severe immunosuppression, the polyomavirus JC (JCV) can cause a lytic infection of oligodendrocytes. This demyelinating disease of the CNS white matter (WM) is called progressive multifocal leukoencephalopathy (PML). JCV has a very narrow host-cell range and productive infection of neurons has never been demonstrated. Patient, methods, and results: An HIV-1-infected patient presented with signs of pyramidal tract and cerebellar dysfunction. Brain MRI revealed T2 hyperintensities in the WM of both frontal lobes and cerebellar atrophy. His disease progressed despite therapy and he died 6 months later. In addition to classic PML findings in the frontal lobe WM, autopsy revealed scattered foci of tissue destruction in the internal granule cell layer (IGCL) of the cerebellum. In these foci, enlarged granule cell neurons identified by the neuronal markers MAP-2 and NeuN reacted with antibodies specific for the polyomavirus VP1 capsid protein. Electron microscopy showed 40 nm viral particles, consistent with polyomaviruses, in these granule cell neurons. In addition, JCV DNA was detected by PCR after laser capture microdissection of cells from the areas of focal cell loss. Finally, in situ hybridization studies demonstrated that many granule cell neurons were infected with JCV but did not contain viral proteins. Sequence analysis of the JCV regulatory region from cerebellar virions showed a tandem repeat pattern also found in PML lesions of the frontal lobe WM. CONCLUSION: JCV can productively infect granule cell neurons of the IGCL of the cerebellum. This suggests a role for JCV infection of neurons in cerebellar atrophy occurring in HIV-infected individuals.     

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

Following the development of progressive multifocal leukoencephalopathy (PML) in two multiple sclerosis (MS) patients treated with natalizumab and interferon-beta (IFNbeta), a possible correlation between JC virus (JCV), the etiological agent of PML, and MS has received heightened interest. In particular, attention has focused on assessing whether IFNbeta treatment could affect the replication of JCV and thus its frequency in the peripheral blood of MS patients and whether the presence of JCV DNA in peripheral blood could be a predictive marker of the risk of developing PML. In order to answer to these questions, peripheral blood samples were collected from 59 INFbeta-treated, 39 untreated relapsing-remitting MS patients, and 98 healthy controls (HCs) and JCV DNA levels were determined and quantified by means of a real-time polymerase chain reaction (Q-PCR) assay. Overall, no differences were found in the presence or viral load of JCV DNA of MS patients and the HCs, but JCV DNA was significantly less frequent in the peripheral blood of IFNbeta-treated patients (13.6%) compared to the untreated MS patients (46.1%) and the healthy controls (28.6%). These results suggest that the presence of JCV in the blood of MS patients cannot be considered as a marker or a risk factor for PML development. In addition, they indicate that treatment with INFbeta can lead to the reduction of presence of the JCV genome in the peripheral blood of MS patients and, thus, that this drug probably does not increase the risk of PML in MS patients treated with IFNbeta.     

Natalizumab vs interferon beta 1a in relapsing-remitting multiple sclerosis: a head-to-head retrospective study

Background – No head‐to‐head study has been performed yet to assess whether natalizumab is more effective than classical immunomodulators in multiple sclerosis (MS). Aim – To retrospectively compare the efficacy of natalizumab vs IFN beta 1a SC (44 μg; Rebif^®) on clinical and radiological findings in two matched cohorts of patients with MS. Patients and methods – We retrospectively enrolled two cohorts of 42 patients (F/M: 35/7) with relapsing‐remitting multiple sclerosis treated with natalizumab or IFN beta 1a for at least 12 consecutive months. Outcome measures were annualized relapse rate (ARR), changes in expanded disability status scale (EDSS) score, and number of contrast‐enhancing lesions (CELs) at magnetic resonance imaging (MRI). Results – In both groups, the ARR in the 12 months of treatment was lower than in the 12 months before therapy (0.24 vs 1.50 in natalizumab‐treated group, P < 0.0000; 0.55 vs 1.10 in IFN beta 1a‐treated group, P = 0.0006), being the effect of natalizumab significantly stronger (P = 0.0125). EDSS reduction was significantly different between the two groups in favor of natalizumab (P = 0.0018). The frequency and number of CELs per patient were decreased in both groups. In the second year, the treatment affected ARR and EDSS progression in the two groups of patients similarly to the first year, whereas number of CELs decreased more significantly in natalizumab group (P = 0.008). Conclusions – After 12 and 24 months of therapy, natalizumab was more effective than IFN beta 1a SC on both disease activity and disability progression. Prospective head‐to‐head studies would be helpful to further evaluate the differences observed in the MRI outcomes.     

The effects of natalizumab on the innate and adaptive immune system in the central nervous system

Multiple sclerosis (MS) is an inflammatory demyelinating disorder of the central nervous system (CNS). Natalizumab ((R)Tysabri) is a humanized recombinant monoclonal antibody that binds to the alpha (alpha)(4) chain of the alpha(4) beta (beta)(1) integrin (very late activation antigen 4; VLA-4), and alpha(4)beta(7) integrin. Recently, two patients with MS and one patient with Crohn's disease who were treated with natalizumab in the setting of clinical trials developed progressive multifocal leukoencephalopathy (PML), an opportunistic infection of the brain with the polyoma virus JC. We recently showed that natalizumab decreases the numbers of CD4(+) and CD8(+) T lymphocytes, CD19(+) B cells, and CD138(+) plasma cells in the cerebrospinal fluid (CSF) of patients with MS on natalizumab therapy. In addition, we demonstrated that the cell numbers in CSF remained unchanged even 6 months after cessation of natalizumab treatment.     

Natalizumab drug holiday in multiple sclerosis: Poorly Tolerated

It has been suggested that natalizumab‐associated progressive multifocal leukoencephalopathy may be prevented by structured interruptions of treatment. Evidence supporting such a drug holiday is not yet available. Here we present initial observations in 10 multiple sclerosis patients who were stringently monitored up to 6 months after discontinuation of the infusions. Cumulatively, a combination of clinical relapse and new and/or enhanced lesions on magnetic resonance imaging had occurred in 7 of 10 patients. Although numbers are small, our data suggest that in patients who were switched to natalizumab because of disease activity despite first‐line treatment, a natalizumab drug holiday without reinstatement of alternate disease‐modifying therapy is poorly tolerated. Ann Neurol 2010     

Pulsed corticosteroid treatment in MS patients stabilizes disease activity following natalizumab withdrawal prior to switching to fingolimod

Purpose: Interruption of natalizumab (NTM) treatment in multiple sclerosis (MS) patients may be followed by disease reactivation. On the other hand, patients with positive John Cunningham virus (JCV) antibodies treated with NTM over 24 months demonstrate a higher risk for developing progressive multifocal encephalopathy (PML). No established therapeutic approach is available for treating these patients to prevent disease reactivation. Materials and methods: Of the MS patients treated with NTM at the authors’ institution, 30 were found positive for JCV abs. NTM was interrupted followed by a washout period of 6 months. During this period, 20/30 patients received monthly intravenous (i.v.) methylprednisolone (MPD) 1000 mg infusion and regular clinical assessment. On months 3 and 6, brain MRI was performed and 1000 mg MPD was administered for 5 days. Results: All patients were clinically and radiologically stable at the time of NTM break. No clinical relapse was observed during the six-month washout period for the MS patients under monthly MPD treatment, while one patient had a relapse and active lesions in the MRI on month 6. Of the other patients not receiving i.v. MPD regularly after NTM withdrawal, one showed several active lesions in brain MRI and the other had a severe relapse. Conclusions: Despite the limited size of this patients’ cohort, the results of this study support that monthly MPD treatment for 6 months may result in a clinically stable disease status, thus ensuring safe transition to another second-line therapy such as fingolimod, following NTM withdrawal.