Assessment of JC virus DNA in blood and urine from natalizumab-treated patients

JC polyomavirus: a short review of its biology, its association with progressive multifocal leukoencephalopathy, and the diagnostic value of different methods to manifest its activity or presence

INTRODUCTION

JC polyomavirus is the causative agent of progressive multifocal leukoencephalopathy (PML), a demyelinating disease resulting from the lytic infection of oligodendrocytes that may develop in immunosuppressed individuals: HIV1 infected or individuals under immunosuppressive therapies. Understanding the biology of JCPyV is necessary for a proper patient management, the development of diagnostic tests, and risk stratification.

AREAS COVERED

The review covers different areas of expertise including the genomic characterization of JCPyV strains detected in different body compartments (urine, plasma, and cerebrospinal fluid) of PML patients, viral mutations, molecular diagnostics, viral miRNAs, and disease.

EXPERT OPINION

The implementation of molecular biology techniques improved our understanding of JCPyV biology. Deep sequencing analysis of viral genomes revealed the presence of viral quasispecies in the cerebrospinal fluid of PML patients characterized by noncoding control region rearrangements and VP1 mutations. These neurotropic JCPyV variants present enhanced replication and an altered cell tropism that contribute to PML development. Monitoring these variants may be relevant for the identification of patients at risk of PML. Multiplex realtime PCR targeting both the LTAg and the archetype NCCR could be used to identify them. Failure to amplify NCCR should indicate the presence of a JCPyV prototype speeding up the diagnostic process.

Comparison of qPCR with ddPCR for the Quantification of JC Polyomavirus in CSF from Patients with Progressive Multifocal Leukoencephalopathy

Background: Lytic infection of oligodendrocytes by the human JC polyomavirus (JCPyV) results in the demyelinating disease called progressive multifocal leukoencephalopathy (PML). The detection of viral DNA in the cerebrospinal fluid (CSF) by PCR is an important diagnostic tool and, in conjunction with defined radiological and clinical features, can provide diagnosis of definite PML, avoiding the need for brain biopsy. The main aim of this study is to compare the droplet digital PCR (ddPCR) assay with the gold standard quantitative PCR (qPCR) for the quantification of JC viral loads in clinical samples. Methods: A total of 62 CSF samples from 31 patients with PML were analyzed to compare the qPCR gold standard technique with ddPCR to detect conserved viral DNA sequences in the JCPyV genome. As part of the validation process, ddPCR results were compared to qPCR data obtained in 42 different laboratories around the world. In addition, the characterization of a novel triplex ddPCR to detect viral DNA sequence from both prototype and archetype variants and a cellular housekeeping reference gene is described. Triplex ddPCR was used to analyze the serum from six PML patients and from three additional cohorts, including 20 healthy controls (HC), 20 patients with multiple sclerosis (MS) who had never been treated with natalizumab (no-NTZ-treated), and 14 patients with MS who were being treated with natalizumab (NTZ-treated); three from this last group seroconverted during the course of treatment with natalizumab. Results: JCPyV DNA was detected only by ddPCR for 5 of the 62 CSF samples (8%), while remaining undetected by qPCR. For nine CSF samples (15%), JCPyV DNA was at the lower limit of quantification for qPCR, set at <250 copies/mL, and therefore no relative quantitation could be determined. By contrast, exact copies of JCPyV for each of these samples were quantified by ddPCR. No differences were observed between qPCR and ddPCR when five standardized plasma samples were analyzed for JCPyV in 42 laboratories in the United States and Europe. JCPyV-DNA was undetected in all the sera from HC and MS cohorts tested by triplex ddPCR, while serum samples from six patients with PML tested positive for JCPyV. Conclusion: This study shows strong correlation between ddPCR and qPCR with increased sensitivity of the ddPCR assay. Further work will be needed to determine whether multiplex ddPCR can be useful to determine PML risk in natalizumab-treated MS patients.

Natalizumab in Multiple Sclerosis Treatment: From Biological Effects to Immune Monitoring

Multiple sclerosis is a chronic demyelinating disease of the central nervous system (CNS) with an autoimmune component. Among the recent disease-modifying treatments available, Natalizumab, a monoclonal antibody directed against the alpha chain of the VLA-4 integrin (CD49d), is a potent inhibitor of cell migration toward the tissues including CNS. It potently reduces relapses and active brain lesions in the relapsing remitting form of the disease. However, it has also been associated with a severe infectious complication, the progressive multifocal leukoencephalitis (PML). Using the standard protocol with an injection every 4 weeks it has been shown by a close monitoring of the drug that trough levels soon reach a plateau with an almost saturation of the target cell receptor as well as a down modulation of this receptor. In this review, mechanisms of action involved in therapeutic efficacy as well as in PML risk will be discussed. Furthermore the interest of a biological monitoring that may be helpful to rapidly adapt treatment is presented. Indeed, development of anti-NAT antibodies, although sometimes unapparent, can be detected indirectly by normalization of CD49d expression on circulating mononuclear cells and might require to switch to another drug. On the other hand a stable modulation of CD49d expression might be useful to follow the circulating NAT levels and apply an extended interval dose scheme that could contribute to limiting the risk of PML.

High effector-memory CD8+ T-cell levels correlate with high PML risk in natalizumab-treated patients

BACKGROUND

Progressive multifocal leukoencephalopathy (PML) is a severe complication of natalizumab (NTZ) treatment in multiple sclerosis (MS) patients. Based on the analysis of cryopreserved cells, several reports have showed that CD62L+ CD4+ T-cells percentage drops before PML onset.

OBJECTIVE

To analyze CD62L and CD45RA expression on fresh-blood CD4+ and CD8+ T-cells from NTZ-treated patients, according to their estimated PML risk.

METHODS

We prospectively enrolled 74 MS patients, including 62 NTZ-treated, and stratified them into low, intermediate and high PML risk groups. Circulating naïve and memory T-cell subsets were analyzed by flow cytometry.

RESULTS

We found no correlation between the percentage of CD62L+ CD4+ T-cells and PML risk. In contrast, the repartition of CD8+ T-cells subpopulations was altered in the high risk group: both the percentage and absolute count of CD8+ CD62L- CD45RA- effector memory T- cells (T_EM) was significantly higher compared to patients at lower risk despite similar CD3+ and CD8+ T-cell counts. One high-risk patient with elevated CD8+ T_EM and CD62L+ CD4+ T-cell levels developed PML six months after sampling.

CONCLUSION

Our results suggest that CD8+ T_EM cells should be evaluated in larger studies as a potential surrogate marker of PML risk in NTZ-treated patients.

Fifty Years of JC Polyomavirus: A Brief Overview and Remaining Questions

In the fifty years since the discovery of JC polyomavirus (JCPyV), the body of research representing our collective knowledge on this virus has grown substantially. As the causative agent of progressive multifocal leukoencephalopathy (PML), an often fatal central nervous system disease, JCPyV remains enigmatic in its ability to live a dual lifestyle. In most individuals, JCPyV reproduces benignly in renal tissues, but in a subset of immunocompromised individuals, JCPyV undergoes rearrangement and begins lytic infection of the central nervous system, subsequently becoming highly debilitating-and in many cases, deadly. Understanding the mechanisms allowing this process to occur is vital to the development of new and more effective diagnosis and treatment options for those at risk of developing PML. Here, we discuss the current state of affairs with regards to JCPyV and PML; first summarizing the history of PML as a disease and then discussing current treatment options and the viral biology of JCPyV as we understand it. We highlight the foundational research published in recent years on PML and JCPyV and attempt to outline which next steps are most necessary to reduce the disease burden of PML in populations at risk.

Two susceptible HLA-DRB1 alleles for multiple sclerosis differentially regulate anti-JC virus antibody serostatus along with fingolimod

Background

Progressive multifocal leukoencephalopathy (PML) caused by JC virus (JCV) is a rare but serious complication of some disease-modifying drugs used to treat multiple sclerosis (MS). Japanese MS patients treated with fingolimod were reported to be 10 times more likely to develop PML than equivalent patients in other countries. The strongest susceptibility human leukocyte antigen (HLA) class II alleles for MS are distinct between races (DRB1*15:01 for Caucasians and DRB1*04:05 and DRB1*15:01 for Japanese); therefore, we investigated whether HLA class II alleles modulate anti-JCV antibody serostatus in Japanese MS patients with and without fingolimod.

Methods

We enrolled 128 Japanese patients with MS, in whom 64 (50%) were under fingolimod treatment at sampling, and examined the relationship between HLA class II alleles and anti-JCV antibody serostatus. Serum anti-JCV antibody positivity and index were measured using a second-generation two-step assay and HLA-DRB1 and -DPB1 alleles were genotyped.

Results

HLA-DRB1*15 carriers had a lower frequency of anti-JCV antibody positivity (57% vs 78%, p = 0.015), and lower antibody index (median 0.42 vs 1.97, p = 0.037) than non-carriers. Among patients without HLA-DRB1*15, DRB1*04 carriers had a higher seropositivity rate than non-carriers (84% vs 54%, p = 0.030), and DPB1*04:02 carriers had a higher anti-JCV antibody index than non-carriers (3.20 vs 1.34, p = 0.008) although anti-JCV antibody-positivity rates did not differ. Patients treated with fingolimod had a higher antibody index than other patients (1.46 vs 0.64, p = 0.039) and treatment period had a positive correlation with antibody index (p = 0.018). Multivariate logistic regression analysis revealed that age was positively associated, and HLA-DRB1*15 was negatively associated with anti-JCV antibody positivity (odds ratio [OR] = 1.06, p = 0.006, and OR = 0.37, p = 0.028, respectively). Excluding HLA-DRB1*15-carriers, DRB1*04 was an independent risk factor for the presence of anti-JCV antibody (OR = 5.50, p = 0.023).

Conclusions

HLA-DRB1*15 is associated with low anti-JCV antibody positive rate and low JCV antibody index, and in the absence of DRB1*15, DRB1*04 carriers are associated with a high antibody positive rate in Japanese, suggesting the effects of two susceptible HLA-DRB1 alleles on anti-JCV antibody serostatus differ.

Established and Emerging Immunological Complications of Biological Therapeutics in Multiple Sclerosis

Biologic immunotherapies have transformed the treatment landscape of multiple sclerosis. Such therapies include recombinant proteins (interferon beta), as well as monoclonal antibodies (natalizumab, alemtuzumab, daclizumab, rituximab and ocrelizumab). Monoclonal antibodies show particular efficacy in the treatment of the inflammatory phase of multiple sclerosis. However, the immunological perturbations caused by biologic therapies are associated with significant immunological adverse reactions. These include development of neutralising immunogenicity, secondary immunodeficiency and secondary autoimmunity. These complications can affect the balance of risks and benefits of biologic agents, and 2018 saw the withdrawal from the market of daclizumab, an anti-CD25 monoclonal antibody, due to concerns about the development of severe, unpredictable autoimmunity. Here we review established and emerging risks associated with multiple sclerosis biologic agents, with an emphasis on their immunological adverse effects. We also discuss the specific challenges that multiple sclerosis biologics pose to drug safety systems, and the potential for improvements in safety frameworks.

Diagnostic and Prognostic Value of JC Virus DNA in Plasma in Progressive Multifocal Leukoencephalopathy

Background

Progressive multifocal leukoencephalopathy (PML) is a severe demyelinating disease caused by the polyomavirus JC (John Cunningham; JCV) that affects patients with impaired immune systems. While JCV-DNA detection in cerebrospinal fluid (CSF) is diagnostic of PML, the clinical significance of plasma JCV-DNA is uncertain.

Methods

We retrospectively analyzed plasma samples from PML patients that were drawn close to disease onset and from controls without PML. In PML patients, we compared plasma JCV-DNA detection and levels to clinical and laboratory parameters, and patient survival.

Results

JCV-DNA was detected in plasma of 49/103 (48%) patients with PML (20/24, 83%, human immunodeficiency virus [HIV] negative; 29/79, 37%, HIV-positive) and of 4/144 (3%) controls without PML (0/95 HIV-negative; 4/49, 8%, HIV-positive), yielding a diagnostic sensitivity and specificity of 48% and 97% (83% and 100% in HIV-negative; 37% and 92% in HIV-positive), respectively. Among 16 PML patients with undetectable CSF JCV-DNA, 4 (25%) had detectable plasma JCV-DNA. Plasma JCV-DNA levels were independently associated with CSF levels (P < .0001) and previous corticosteroid treatment (P = .012). Higher plasma JCV-DNA levels were associated with disease progression in HIV-negative patients (P = .005); in HIV-positive patients, there was an increased risk of progression only in those treated with combination antiretroviral therapy (cART; P < .0001).

Conclusions

Testing JCV-DNA in plasma might complement PML diagnosis, especially when CSF is unavailable or JCV-DNA not detectable in CSF. In addition, JCV-DNA plasma levels could be useful as a marker of disease progression in both HIV-negative and cART-treated, HIV-positive PML patients.

A Programme for Risk Assessment and Minimisation of Progressive Multifocal Leukoencephalopathy Developed for Vedolizumab Clinical Trials

Introduction

Over the past decade, the potential for drug-associated progressive multifocal leukoencephalopathy (PML) has become an increasingly important consideration in certain drug development programmes, particularly those of immunomodulatory biologics. Whether the risk of PML with an investigational agent is proven (e.g. extrapolated from relevant experience, such as a class effect) or merely theoretical, the serious consequences of acquiring PML require careful risk minimisation and assessment. No single standard for such risk minimisation exists. Vedolizumab is a recently developed monoclonal antibody to α4β7 integrin. Its clinical development necessitated a dedicated PML risk minimisation assessment as part of a global preapproval regulatory requirement.

Objective

The aim of this study was to describe the multiple risk minimisation elements that were incorporated in vedolizumab clinical trials in inflammatory bowel disease patients as part of the risk assessment and minimisation of PML programme for vedolizumab.

Methods

A case evaluation algorithm was developed for sequential screening and diagnostic evaluation of subjects who met criteria that indicated a clinical suspicion of PML. An Independent Adjudication Committee provided an independent, unbiased opinion regarding the likelihood of PML.

Results

Although no cases were detected, all suspected PML events were thoroughly reviewed and successfully adjudicated, making it unlikely that cases were missed.

Conclusion

We suggest that this programme could serve as a model for pragmatic screening for PML during the clinical development of new drugs.

Electronic supplementary material

The online version of this article (10.1007/s40264-018-0669-8) contains supplementary material, which is available to authorized users.

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.

Diagnosis and Treatment of Progressive Multifocal Leukoencephalopathy Associated with Multiple Sclerosis Therapies

Progressive multifocal leukoencephalopathy (PML) is a rare, but serious, complication encountered in patients treated with a select number of disease-modifying therapies (DMTs) utilized in treating multiple sclerosis (MS). PML results from a viral infection in the brain for which the only demonstrated effective therapy is restoring the perturbed immune system-typically achieved in the patient with MS by removing the offending therapeutic agent or, in the case of HIV-associated PML, treatment with highly active antiretroviral therapies. Other therapies for PML remain either ineffective or experimental. Significant work to understand the virus and host interaction has been undertaken, but lack of an animal model for the disorder has significantly hindered progress, especially with respect to development of treatments. Strategies to limit risk of PML with natalizumab, a drug that carries a uniquely high risk for the development of the disorder, have been developed. Identifying factors such as positive JC virus antibody status that increase PML risk, at least in theory, should decrease the incidence rate of the disease. Whether other risk factors for PML can be identified and validated or unique strategies should be employed in association with other DMTs that predispose to PML and whether this has a salutary effect on outcome remains to be demonstrated. Identifying PML early, then promptly eliminating drug in the case of natalizumab-associated PML has demonstrated better outcomes, but the complication of PML continues to carry significant morbidity and mortality. While the scientific community has yet to identify targeted therapy with proven efficacy against JCV or PML there are several candidates being studied.

Safety concerns and risk management of multiple sclerosis therapies

Currently, more than ten drugs have been approved for treatment of relapsing-remitting multiple sclerosis (MS). Newer treatments may be more effective, but have less favorable safety record. Interferon-β preparations and glatiramer acetate treatment require frequent subcutaneous or intramuscular injections and are only moderately effective, but have very rarely life-threatening adverse effects, whereas teriflunomide and dimethyl fumarate are administered orally and have equal or better efficacy, but have more potentially severe adverse effects. The highly effective therapies fingolimod, natalizumab, daclizumab, and alemtuzumab have more serious adverse effects, some of which may be life-threatening. The choice between drugs should be based on a benefit-risk evaluation and tailored to the individual patient's requirements in a dialogue between the patient and treating neurologist. Patients with average disease activity can choose between dimethyl fumarate and teriflunomide or the "old injectable." Patients with very active MS may choose a more effective drug as the initial treatment. In case of side effects on one drug, switch to another drug can be tried. Suboptimal effect of the first drug indicates escalation to a highly efficacious drug. A favorable benefit-risk balance can be maintained by appropriate patient selection and appropriate risk management on therapy. New treatments will within the coming 1-2 years change our current treatment algorithm for relapsing-remitting MS.

Evolving concepts in the treatment of relapsing multiple sclerosis

In the past 20 years the treatment scenario of multiple sclerosis has radically changed. The increasing availability of effective disease-modifying therapies has shifted the aim of therapeutic interventions from a reduction in relapses and disability accrual, to the absence of any sign of clinical or MRI activity. The choice for therapy is increasingly complex and should be driven by an appropriate knowledge of the mechanisms of action of the different drugs and of their risk-benefit profile. Because the relapsing phase of the disease is characterised by inflammation, treatment should be started as early as possible and aim to re-establish the normal complex interactions in the immune system. Before starting a treatment, neurologists should carefully consider the state of the disease, its prognostic factors and comorbidities, the patient's response to previous treatments, and whether the patient is likely to accept treatment-related risks in order to maximise benefits and minimise risks. Early detection of suboptimum responders, thanks to accurate clinical monitoring, will allow clinicians to redesign treatment strategies where necessary.

From Evolutionary Advantage to Disease Agents: Forensic Reevaluation of Host-Microbe Interactions and Pathogenicity

As the "human microbiome era" continues, there is an increasing awareness of our resident microbiota and its indispensable role in our fitness as holobionts. However, the host-microbe relationship is not so clearly defined for some human symbionts. Here we discuss examples of "accidental pathogens," meaning previously nonpathogenic and/or environmental microbes thought to have inadvertently experienced an evolutionary shift toward pathogenicity. For instance, symbionts such as Helicobacter pylori and JC polyomavirus have been shown to have accompanied humans since prehistoric times and are still abundant in extant populations as part of the microbiome. And yet, the relationship between a subgroup of these microbes and their human hosts seems to have changed with time, and they have recently gained notoriety as gastrointestinal and neuropathogens, respectively. On the other hand, environmental microbes such as Legionella spp. have recently experienced a shift in host range and are now a major problem in industrialized countries as a result of artificial ecosystems. Other variables involved in this accidental phenomenon could be the apparent change or reduction in the diversity of human-associated microbiota because of modern medicine and lifestyles. All of this could result in an increased prevalence of accidental pathogens in the form of emerging pathogens.

Natalizumab Affects T-Cell Phenotype in Multiple Sclerosis: Implications for JCV Reactivation

The anti-CD49d monoclonal antibody natalizumab is currently an effective therapy against the relapsing-remitting form of multiple sclerosis (RRMS). Natalizumab therapeutic efficacy is limited by the reactivation of the John Cunningham polyomavirus (JCV) and development of progressive multifocal leukoencephalopathy (PML). To correlate natalizumab-induced phenotypic modifications of peripheral blood T-lymphocytes with JCV reactivation, JCV-specific antibodies (serum), JCV-DNA (blood and urine), CD49d expression and relative abundance of peripheral blood T-lymphocyte subsets were longitudinally assessed in 26 natalizumab-treated RRMS patients. Statistical analyses were performed using GraphPad Prism and R. Natalizumab treatment reduced CD49d expression on memory and effector subsets of peripheral blood T-lymphocytes. Moreover, accumulation of peripheral blood CD8⁺ memory and effector cells was observed after 12 and 24 months of treatment. CD4⁺ and CD8⁺ T-lymphocyte immune-activation was increased after 24 months of treatment. Higher percentages of CD8⁺ effectors were observed in subjects with detectable JCV-DNA. Natalizumab reduces CD49d expression on CD8⁺ T-lymphocyte memory and effector subsets, limiting their migration to the central nervous system and determining their accumulation in peripheral blood. Impairment of central nervous system immune surveillance and reactivation of latent JCV, can explain the increased risk of PML development in natalizumab-treated RRMS subjects.

Utility of droplet digital PCR for the quantitative detection of polyomavirus JC in clinical samples

BACKGROUND

Quantitative PCR (qPCR) is the standard molecular method for detection of polyomavirus JC (JCPyV) DNA reactivation in serum and cerebrospinal fluid (CSF) in patients at risk of progressive multifocal leukoencephalopathy (PML). Recently, digital PCR has shown potential benefits over qPCR in viral diagnostics.

OBJECTIVE

To evaluate the performance of droplet digital PCR (ddPCR) assay in assessing JCPyV-DNA status in clinical samples of patients at risk for PML.

STUDY DESIGN

JCPyV specific ddPCR was developed with primers/probes targeting Large T and the noncoding control region used in qPCR. The ddPCR accuracy of JCPyV-DNA quantification was investigated using serial dilutions of genomic JCPyV-DNA. The ddPCR JCPyV-DNA quantification and qPCR confirmation were performed on 150 CSF and 100 serum clinical samples.

RESULTS

Using genomic JCPyV-DNA, ddPCR was highly sensitive, repeatable and reproducible for both molecular targets. Using clinical samples, JCPyV-DNA was detected in 13% of CSF and in 50% of serum samples with limit of detection of 30 copies/ml. Among the 19 JCPyV-DNA-positive CSF detected using the ddPCR, 15 also tested positive with the qPCR. Among the 50 JCPyV-DNA-positive serum identified with ddPCR, 41 tested positive with qPCR. All the ddPCR-negative samples were negative when assessed using qPCR. Additionally, the mean JCPyV-DNA viral load obtained with ddPCR in all samples was not significantly different from that of qPCR.

CONCLUSION

The results demonstrate that ddPCR is a highly sensitive alternative for measuring JCPyV-DNA that should be considered in clinical diagnostic testing of JCPyV-DNA in patients at risk of PML and other associated diseases.

Natalizumab-treated patients at high risk for PML persistently excrete JC polyomavirus

Sixty-three natalizumab-treated patients with relapsing multiple sclerosis were screened for JC polyomavirus (JCV) viruria. Urinary-positive patients were longitudinally sampled for up to 24 weeks. Using methods that distinguish encapsidated virus from naked viral DNA, 17.5 % of patients were found to excrete virus, consistent with the prevalence of urinary excretion in the general population. Unexpectedly, urinary excretion was predominantly seen (>73 %) in patients with high JC antibody index (≥2.0). Active JCV infection, therefore, tends to occur in natalizumab patients that carry a high risk factor for the development of disease, directly linking JC infection to the risk factors for PML development.

High cumulative JC virus seroconversion rate during long-term use of natalizumab

BACKGROUND AND PURPOSE

John Cunningham virus (JCV) seropositivity is a risk factor for the development of natalizumab-associated progressive multifocal leukoencephalopathy (PML) in multiple sclerosis (MS) patients. When JCV seronegative patients seroconvert, their risk of developing PML increases. Limited longitudinal data exist about the seroconversion rate amongst natalizumab-treated relapsing-remitting MS (RRMS) patients. Our objective was to evaluate the seroconversion rate in a large Dutch cohort of natalizumab-treated RRMS patients. Seroconversion was defined as at least two consecutive seropositive serum samples (or cessation of therapy after a single seropositive sample because of seropositivity) after initial seronegative testing.

METHODS AND RESULTS

In our study of 179 patients for whom longitudinal blood samples were available over a long period (median 4.2 years), anti-JCV antibody indices were measured in 933 available samples. Eighty-six patients (48.0%) tested seronegative initially. Of these 86 seronegative patients, 23 patients (26.7%) seroconverted during follow-up. The annualized seroconversion rate was 7.1%. Seroconversion occurred between 9 and 90 months (median 43 months) of treatment. The rate of seroconversion was independent of follow-up duration. No significant increase was seen in the anti-JCV antibody index in the non-converting patients during the follow-up.

CONCLUSION

The annualized seroconversion rate of 7.1% in patients using natalizumab, cumulatively leading to more than 25% of seronegative patients becoming seropositive in 4 years, is of clinical relevance and should be taken into account in the risk assessment when considering the start of natalizumab therapy.

Immunotherapies for Neurological Manifestations in the Context of Systemic Autoimmunity

Neurological involvement is relatively common in the majority of systemic autoimmune diseases and may lead to severe morbidity and mortality, if not promptly treated. Treatment options vary greatly, depending on the underlying systemic pathophysiology and the associated neurological symptoms. Selecting the appropriate therapeutic scheme is further complicated by the lack of definite therapeutic guidelines, the necessity to differentiate primary neurological syndromes from those related to the underlying systemic disease, and to sort out adverse neurological manifestations caused by immunosuppressants or the biological agents used to treat the primary disease. Immunotherapy is a sine qua non for treating most, if not all, neurological conditions presenting in the context of systemic autoimmunity. Specific agents include classical immune modulators such as corticosteroids, cyclophosphamide, intravenous immunoglobulin, and plasma exchange, as well as numerous biological therapies, for example anti-tumor necrosis factor agents and monoclonal antibodies that target various immune pathways such as B cells, cytokines, and co-stimulatory molecules. However, experience regarding the use of these agents in neurological complications of systemic diseases is mainly empirical or based on small uncontrolled studies and case series. The aim of this review is to present the state-of-the-art therapies applied in various neurological manifestations encountered in the context of systemic autoimmune diseases; evaluate all treatment options on the basis of existing guidelines; and compliment these data with our personal experience derived from a large number of patients.

Diagnostic assays for polyomavirus JC and progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is a devastating and often fatal demyelinating disease of the central nervous system for which effective therapies are lacking. It is caused by the replication of polyomavirus JC (JCV) in the oligodendrocytes and astrocytes leading to their cytolytic death and loss of myelin from the subcortical white matter. While the virus is very common in human populations worldwide, the incidence of the disease is very low and confined almost exclusively to individuals with some form of immunological dysfunction. However, the number of people who constitute the at-risk population is growing larger and includes individuals with HIV-1/AIDS and patients receiving immunomodulatory therapies such as multiple sclerosis patients treated with natalizumab. Further adding to the public health significance of this disease are the difficulties encountered in the diagnosis of PML and the lack of useful biomarkers for PML progression. In this review, we examine the diagnostic assays that are available for different aspects of the JCV life cycle, their usefulness and drawbacks, and the prospects for improvements.

Human polyomavirus JC replication and non-coding control region analysis in multiple sclerosis patients under natalizumab treatment

In the last years, the treatment of multiple sclerosis (MS) patients with natalizumab has been associated with the occurrence of progressive multifocal leukoencephalopathy (PML) caused by human polyomavirus JC (JCV). Here, we have shown a significant correlation between patients with JC viruria and positive JC-specific antibody response and patients without JCV-specific antibodies after 1 year of natalizumab (p = 0.0006). Furthermore, JCV-specific quantitative PCR on urine and plasma samples, collected at the enrollment (t0) and every 4 months (t1, t2, t3) in the first year and at two time points (t4 and t5) in the second year of natalizumab treatment, indicated the prevalence of JC viremia rather than JC viruria only in the second year of treatment (p = 0.04). Moreover, the analysis of JCV non-coding control region (NCCR) sequences in peripheral blood mononuclear cells of patients with JC-specific antibodies after 12 natalizumab infusions (t3) revealed the presence of rearranged sequences, whereas the prevalence of genotypes 1A, 1B, and 4 was detected in these patients by VP1 sequence analysis. In summary, JC viruria evaluation seems to be useful to identify early those patients who do not already develop a humoral immune response against JCV. It may also be interesting to study the JCV NCCR rearrangements since they could give us new insights on the onset of neuro-invasive viral variants.

Synthetic antibodies and peptides recognizing progressive multifocal leukoencephalopathy-specific point mutations in polyomavirus JC capsid viral protein 1

Polyomavirus JC (JCV) is the causative agent of progressive multifocal leukoencephalopathy (PML), a rare and frequently fatal brain disease that afflicts a small fraction of the immune-compromised population, including those affected by AIDS and transplantation recipients on immunosuppressive drug therapy. Currently there is no specific therapy for PML. The major capsid viral protein 1 (VP1) involved in binding to sialic acid cell receptors is believed to be a key player in pathogenesis. PML-specific mutations in JCV VP1 sequences present at the binding pocket of sialic acid cell receptors, such as L55F and S269F, abolish sialic acid recognition and might favor PML onset. Early diagnosis of these PML-specific mutations may help identify patients at high risk of PML, thus reducing the risks associated with immunosuppressive therapy. As a first step in the development of such early diagnostic tools, we report identification and characterization of affinity reagents that specifically recognize PML-specific mutations in VP1 variants using phage display technology. We first identified 2 peptides targeting wild type VP1 with moderate specificity. Fine-tuning via selection of biased libraries designed based on 2 parental peptides yielded peptides with different, yet still moderate, bindinspecificities. In contrast, we had great success in identifying synthetic antibodies that recognize one of the PML-specific mutations (L55F) with high specificity from the phage-displayed libraries. These peptides and synthetic antibodies represent potential candidates for developing tailored immune-based assays for PML risk stratification in addition to complementing affinity reagents currently available for the study of PML and JCV.

Increased prevalence of JC polyomavirus viruria was associated with arthritis/arthralgia in patients with systemic lupus erythematosus

OBJECTIVE

The objective of this paper is to investigate the prevalence of reactivation of the human polyomavirus John Cunningham virus (JCV) in patients with systemic lupus erythematosus (SLE) and its associated clinical manifestations.

METHODS

Sixty-one patients with SLE and 22 controls were enrolled. Urine JCV viral load was quantified by real-time polymerase chain reaction (PCR). Length variants of the VP1 gene were analyzed using capillary electrophoresis.

RESULTS

The prevalence of JCV viruria (63.9% vs. 18.2%, p < 0.001) and urine JCV viral load (2.92 ± 2.76 vs. 0.81 ± 1.85 copies/ml by log10 scale, p < 0.001) were significantly higher in patients with SLE compared with controls. JCV viruria (+) SLE patients had a higher occurrence of arthritis/arthralgia compared with JCV viruria (-) SLE patients (64.1% vs. 22.7%, p = 0.003). In SLE patients, the urine JCV viral load was significantly associated with the occurrence of arthritis/arthralgia. SLE patients with urine JCV viral load >10,000 copies/ml exhibited a 12.75-fold (95% confidence interval 2.88-56.40) risk in clinical arthritis/arthralgia, 18.90-fold (95% confidence interval 2.10-170.39) risk in persistent arthritis, and significantly greater number of length variants in the VP1 gene of JCV compared with JCV viruria (-) SLE patients.

CONCLUSION

Reactivation of JCV in the urinary tract of SLE patients was very common. Both JCV viruria and urine JCV viral load were associated with the occurrence of arthritis/arthralgia in patients with SLE. High urine JCV viral load also was associated with the genetic variant in the VP1 gene.

JC virus antibody index in natalizumab-treated patients: correlations with John Cunningham virus DNA and C-reactive protein level

Natalizumab-treated patients have a higher risk of developing progressive multifocal leukoencephalopathy. Exposure to John Cunningham virus (JCV) is a prerequisite for PML (progressive multifocal leukoencephalopathy). To assess JCV exposure in multiple sclerosis patients, we performed a serological examination, obtained the antibody index, performed real-time polymerase chain reaction (PCR) to detect JCV DNA in plasma and urine, and investigated the role of ultrasensitive C-reactive protein (usCRP) as a possible biological marker of JCV reactivation. We retrospectively analyzed consecutive natalizumab-treated multiple sclerosis patients who underwent a JCV antibody test through a two-step enzyme-linked immunosorbent assay (STRATIFY test) to the measure of serum usCRP levels, and to perform blood and urine JCV PCR. The studied cohort included 97 relapsing–remitting patients (60 women). Fifty-two patients (53.6%) tested positive for anti-JCV antibodies. PCR showed JCV DNA in the urine of 30 out of 83 (36.1%) patients and 28 out of 44 seropositive patients (63.6%), with a 6.7% false-negative rate for the STRATIFY test. Normalized optical density values were higher in urinary JCV DNA-positive patients (P<0.0001). Interestingly, the level of usCRP was higher in urinary JCV DNA-positive patients and correlated to the number of DNA copies in urine (P=0.028). As expected, patients’ age correlated with JCV seropositivity and with JC viruria (P=0.02 and P=0.001, respectively). JC viruria was significantly correlated with a high JCV antibody index and high serum usCRP levels. We suggest that PCR and usCRP might be useful as markers of JCV reactivation, and that patients should be monitored between STRATIFY assessments.

Viral miRNAs in plasma and urine divulge JC polyomavirus infection

BACKGROUND

JC polyomavirus (JCPyV) is a widespread human polyomavirus that usually resides latently in its host, but can be reactivated under immune-compromised conditions potentially causing Progressive Multifocal Leukoencephalopathy (PML). JCPyV encodes its own microRNA, jcv-miR-J1.

METHODS

We have investigated in 50 healthy subjects whether jcv-miR-J1-5p (and its variant jcv-miR-J1a-5p) can be detected in plasma or urine.

RESULTS

We found that the overall detection rate of JCPyV miRNA was 74% (37/50) in plasma and 62% (31/50) in urine. Subjects were further categorized based on JCPyV VP1 serology status and viral shedding. In seronegative subjects, JCPyV miRNA was found in 86% (12/14) and 57% (8/14) of plasma and urine samples, respectively. In seropositive subjects, the detection rate was 69% (25/36) and 64% (23/36) for plasma and urine, respectively. Furthermore, in seropositive subjects shedding virus in urine, higher levels of urinary viral miRNAs were observed, compared to non-shedding seropositive subjects (P < 0.001). No correlation was observed between urinary and plasma miRNAs.

CONCLUSION

These data indicate that analysis of circulating viral miRNAs divulge the presence of latent JCPyV infection allowing further stratification of seropositive individuals. Also, our data indicate higher infection rates than would be expected from serology alone.

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.

JC virus reactivation during prolonged natalizumab monotherapy for multiple sclerosis

OBJECTIVE

To determine the prevalence of JC virus (JCV) reactivation and JCV-specific cellular immune response during prolonged natalizumab treatment for multiple sclerosis (MS).

METHODS

We enrolled 43 JCV-seropositive MS patients, including 32 on natalizumab monotherapy >18 months, 6 on interferon β-1a monotherapy >36 months, and 5 untreated controls. We performed quantitative real-time polymerase chain reaction in cerebrospinal fluid (CSF), blood, and urine for JCV DNA, and we determined JCV-specific T-cell responses using enzyme-linked immunosorbent spot (ELISpot) and intracellular cytokine staining (ICS) assays, ex vivo and after in vitro stimulation with JCV peptides.

RESULTS

JCV DNA was detected in the CSF of 2 of 27 (7.4%) natalizumab-treated MS patients who had no symptoms or magnetic resonance imaging-detected lesions consistent with progressive multifocal leukoencephalopathy. JCV DNA was detected in blood of 12 of 43 (27.9%) and in urine of 11 of 43 (25.6%) subjects without a difference between natalizumab-treated patients and controls. JC viral load was higher in CD34(+) cells and in monocytes compared to other subpopulations. ICS was more sensitive than ELISpot. JCV-specific T-cell responses, mediated by both CD4(+) and CD8(+) T lymphocytes, were detected more frequently after in vitro stimulation. JCV-specific CD4(+) T cells were detected ex vivo more frequently in MS patients with JCV DNA in CD34(+) (p = 0.05) and B cells (p = 0.03).

INTERPRETATION

Asymptomatic JCV reactivation may occur in CSF of natalizumab-treated MS patients. JCV DNA load is higher in circulating CD34(+) cells and monocytes compared to other mononuclear cells, and JCV in blood might trigger a JCV-specific CD4(+) T-cell response. JCV-specific cellular immune response is highly prevalent in all JCV-seropositive MS patients, regardless of treatment.

Long-term safety and efficacy of natalizumab in relapsing-remitting multiple sclerosis: impact on quality of life

Natalizumab was the first monoclonal antibody to be approved for the treatment of relapsing-remitting multiple sclerosis (RRMS) based on its short-term efficacy and overall tolerability. However, the incidence of treatment-associated progressive multifocal leukoencephalopathy (PML), an infection of the brain caused by the John Cunningham virus, jeopardized this efficacious treatment from the beginning. Eight years after licensing of natalizumab, long-term studies confirm the considerable and sustained efficacy of natalizumab, although the PML complication still threatens one of the most successful treatments available for RRMS. During these years, considerable progress has been made in identification of risk factors that allow more effective management of PML risk. In addition, long-term studies to define better when to start or stop treatment and to optimize treatment strategies after cessation of natalizumab are ongoing, and hopefully will improve management and will allow natalizumab to remain as a valuable therapeutic option for patients with highly active RRMS.

Prevalence of Anti-JC Virus Antibody in Multiple Sclerosis Patients in Kuwait

Background. Multiple sclerosis (MS) therapeutics entered a new era after the development of anti-JC virus (anti-JCV) antibody assay that assesses the risk of development of progressive multifocal leukoencephalopathy (PML) in patients treated with natalizumab. Objective. To determine the prevalence of anti-JCV antibody among MS patients in Kuwait. Methods. Using the national MS registry, demographics and disease characteristics of MS patients who were screened for anti-JC virus antibody were collected. The prevalence of anti-JCV antibody seropositivity and its association with demographic and disease characteristics were evaluated. Results. Out of 110 screened MS patients for anti-JCV antibodies, 65.5% were females. Mean age and disease duration were 29.23 ± 8.55 and 5.39 ± 5.04 years, respectively. 47.3% of patients were already on natalizumab and 52.7% of patients were screened for stratification to either natalizumab or a different Disease Modifying Therapy (DMT). The overall prevalence of anti-JC virus antibody was 40%. Gender (P = 0.69), disease duration (P = 0.11), and number of natalizumab infusions (P = 0.64) were not associated with seropositivity. Patients aged ≥30 years were more likely to be seropositive (P = 0.01). Conclusion. The prevalence of anti-JCV antibody is slightly lower than what is reported in published studies. Seropositivity was associated with an increasing age of MS patients.

Biomarkers of treatment response in multiple sclerosis

Multiple sclerosis (MS) is considered a heterogeneous disease with respect to disease progression and treatment response, which have both remained highly unpredictable. With an increasing number of available disease modifying therapies, strategies for treatment allocation in the individual patient or subgroup of patients has become more important. Therefore biomarkers, which will identify subgroups of MS patients and predict treatment response early in the course of the disease, are urgently needed. Here we review current and emerging biomarkers, as well as study concepts for identification of new biomarkers in MS.

Natalizumab for multiple sclerosis: appraising risk versus benefit, a seemingly demanding tango

INTRODUCTION

Natalizumab is a highly effective monoclonal antibody used for the treatment of multiple sclerosis (MS). It reduces relapses, delays the onset of disease progression and improves disease outcomes in relapsing-remitting MS. However, treatment with natalizumab is associated with progressive multifocal leukoencephalopathy (PML), a severe opportunistic brain infection with John Cunningham virus.

AREAS COVERED

In this review, we discuss the mechanism of action, results of pivotal studies, clinical use and adverse effects associated with natalizumab therapy with emphasis on PML. A risk stratification strategy to optimize natalizumab therapy is included. This review also summarizes the alternative and upcoming therapies available for the treatment of MS.

EXPERT OPINION

Natalizumab is a very effective therapy for MS and has shown tremendous results in reducing the disease activity and improving patients' quality of life. Serious adverse effect such as PML warrant extreme caution and heightened clinical vigilance while prescribing the drug. If used with prudence, the drug can be instrumental in treatment of patients with inadequate response to the first-line medications.

Human Polyomavirus JC monitoring and noncoding control region analysis in dynamic cohorts of individuals affected by immune-mediated diseases under treatment with biologics: an observational study

BACKGROUND

Progressive multifocal leukoencephalopathy (PML) onset, caused by Polyomavirus JC (JCPyV) in patients affected by immune-mediated diseases during biological treatment, raised concerns about the safety profile of these agents. Therefore, the aims of this study were the JCPyV reactivation monitoring and the noncoding control region (NCCR) and viral protein 1 (VP1) analysis in patients affected by different immune-mediated diseases and treated with biologics.

METHODS

We performed JCPyV-specific quantitative PCR of biological samples collected at moment of recruitment (t0) and every 4 months (t1, t2, t3, t4). Subsequently, rearrangements' analysis of NCCR and VP1 was carried out. Data were analyzed using χ2 test.

RESULTS

Results showed that at t0 patients with chronic inflammatory rheumatic diseases presented a JCPyV load in the urine significantly higher (p≤0.05) than in patients with multiple sclerosis (MS) and Crohn's disease (CD). It can also be observed a significant association between JC viruria and JCPyV antibodies after 1 year of natalizumab (p=0.04) in MS patients. Finally, NCCR analysis showed the presence of an archetype-like sequence in all urine samples, whereas a rearranged NCCR Type IR was found in colon-rectal biopsies collected from 2 CD patients after 16 months of infliximab. Furthermore, sequences isolated from peripheral blood mononuclear cells (PBMCs) of 2 MS patients with JCPyV antibody at t0 and t3, showed a NCCR Type IIR with a duplication of a 98 bp unit and a 66 bp insert, resulting in a boxB deletion and 37 T to G transversion into the Spi-B binding site. In all patients, a prevalence of genotypes 1A and 1B, the predominant JCPyV genotypes in Europe, was observed.

CONCLUSIONS

It has been important to understand whether the specific inflammatory scenario in different immune-mediated diseases could affect JCPyV reactivation from latency, in particular from kidneys. Moreover, for a more accurate PML risk stratification, testing JC viruria seems to be useful to identify patients who harbor JCPyV but with an undetectable JCPyV-specific humoral immune response. In these patients, it may also be important to study the JCPyV NCCR rearrangement: in particular, Spi-B expression in PBMCs could play a crucial role in JCPyV replication and NCCR rearrangement.

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.

Analysis of JC virus DNA in NPSLE patients treated with different immunomodulatory agents

Objective

The objective of this report is to assess the presence and viral load of JC polyomavirus (JCV) DNA in cerebrospinal fluid (CSF) and plasma from neuropsychiatric systemic lupus erythematosus (NPSLE) patients in comparison to controls and to investigate if different types of immunosuppressive treatments were correlated to detection and viral load of JCV DNA in SLE.

Background

Reactivation of a latent JCV infection with subsequent development of the fatal disease progressive multifocal leukoencephalopathy (PML) has become an increasing problem in patients with autoimmune diseases treated with newer immunosuppressants. Accumulating data point out that SLE patients are at particular risk for PML compared to patients with other rheumatic diseases.

Methods

CSF samples ( n = 69) and plasma samples ( n = 51) from 71 SLE patients and 58 controls (53 CSF samples and 50 plasma samples) with other non-inflammatory neurological disease (OND) were analyzed for JCV DNA with a quantitative PCR method.

Results

All CSF and plasma samples from NPSLE patients and controls were negative for JCV DNA.

Conclusion

JCV DNA was absent in CSF and plasma in NPSLE patients and controls and consequently we were not able to identify any correlation between the occurrence of JCV DNA and type of immunosuppressive medication.

JC virus detection and JC virus-specific immunity in natalizumab-treated multiple sclerosis patients

Background

The use of natalizumab in multiple sclerosis (MS) may favour JC virus reactivation; this phenomenon is usually asymptomatic but can, albeit rarely, evolve into frank progressive multifocal leucoencephalopathy (PML).

Methods

JCV-specific CD8+ T lymphocytes were evaluated by flow cytometry over a 24-month period in 24 natalizumab-treated MS patients in whom JCV DNA was or was not detected in blood using quantitative real-time polymerase chain reaction; all these cases were asymptomatic.

Results

Perforin- and grazymes-containing VP-1-specific CD8+ T lymphocytes were reduced whereas CD107a-expressing cells were increased in JCV positive patients, suggesting an active degranulation of these cells; naïve CD8+ T lymphocytes were also decreased whereas memory cells were increased in patients in whom JCV reactivation was observed.

Conclusion

The presence of a CD8+ T lymphocyte-mediated effector immune response offers a greater insight into reactivation of JCV and its clinical sequelae, and may help the monitoring of patients on natalizumab therapy.