Risk Of Progressive Multifocal Leukoencephalopathy Research Articles

MRI activity and extended interval of Natalizumab dosing regimen: a multicentre Italian study

BackgroundTo minimize the risk of Progressive Multifocal Leukoencephalopathy and rebound in JCV-positive multiple sclerosis (MS) patients after 24 natalizumab doses, it has been proposed to extend the administrations interval. The objective is to evaluate the EID efficacy on MRI activity compared with the standard interval dosing (SID). MethodsObservational, multicentre, retrospective cohort study, starting from the 24th natalizumab infusion to the loss of follow-up or 2 years after baseline. Three hundred and sixteen patients were enrolled. The median dose interval (MDI) following the 24th infusion was 5 weeks, with a bimodal distribution (modes at 4 and 6 weeks). Patients were grouped into 2 categories according to the mean number of weeks between doses: <5 weeks, SID; ≥5 weeks, EID. ResultsOne hundred and eighty-seven patients were in the SID group (MDI = 4.5 weeks) and 129 in the EID group (MDI 6.1 weeks). The risk to develop active lesions on MRI is similar in SID and EID groups during the 6 and 12 months after the 24th natalizumab infusion, respectively 4.27% (95% CI:0.84–7.70) vs 4.71% (95% CI:0.16–9.25%) [p = 0.89] and 8.50% (95% CI:4.05–12.95) vs 6.55% (95% CI:2.11–11.00%) [p = 0.56]. The EID regimen does not appear to increase the occurrence of MRI activity during follow-up. ConclusionThere is no evidence of the reduced efficacy of natalizumab in an EID setting regarding the MRI activity. This observation supports the need for a bigger randomized study to assess the need to change the standard of the natalizumab dosing schedule, to better manage JCV-positive patients.

JC Virus Propagation is Potentiated by Glial Replication and Accelerated by Demyelination-Associated Glial Proliferation

Progressive multifocal leukoencephalopathy (PML) is a demyelinating infection of the immunosuppressed brain, mediated by the gliotropic polyomavirus JCV. JCV replicates in human glial progenitor cells and astrocytes, which undergo viral T antigen-triggered mitosis, enabling viral replication. We asked if JCV spread might therefore be accelerated by glial proliferation. We found that dividing human astrocytes supported JCV propagation more than mitotically quiescent cells. Both bulk and single cell RNA-seq revealed that these JCV-infected glia exhibited cell cycle-linked perturbation of DNA damage response and transcriptional regulatory pathways. In vivo, JCV infection of humanized glial chimeras was greatly accentuated by cuprizone-induced demyelination and its associated mobilization of GPCs. Infection triggered the death of uninfected as well as infected glia in vivo, reflecting significant bystander death. These data suggest that demyelination-associated glial proliferation accelerates the spread of JCV, and argue for the aggressive prevention of new demyelinating events in patients at risk for PML.

Reduction of the risk of PML in natalizumab treated MS patients in Sweden: An effect of improved PML risk surveillance

BackgroundNatalizumab (NTZ) treatment of multiple sclerosis (MS) has been associated with increased risk of progressive multifocal leukoencephalopathy (PML). The aim of the present study was to evaluate the impact of PML risk assessment on PML incidence in NTZ treated MS patients. MethodsBy using information from the population-based Swedish MS registry a retrospective cohort was established of patients treated with NTZ between 2006-2018. The effect on PML incidence before and after utilizing a risk management plan, including JC virus (JCV) serology, was analyzed. ResultsIn December 2018, 804 PML cases associated with NTZ therapy of MS had been reported globally, including 9 cases from Sweden. The estimated PML incidence 2018 in Sweden and globally was 0.7 (0.3-1.4) and 4.15 (3.9-4.4) per 1,000 person years, respectively. In Sweden, JCV serology was introduced 2012 for PML risk assessment and the cumulative risk of PML was significantly lower 2012-2018 compared to the period 2006-2011 (p=0.042). The mean NTZ exposure time was 60.1 months (SD 37.2) in the first period (2006-2011) and 32.6 months (SD 22.0) in the second period (2012-2018). The number of patients treated with NTZ decreased, and the number of patients at increased risk of PML was 1.9 % at the end of the study period. ConclusionSince 2006 the incidence of PML associated with NTZ treatment of MS has decreased in Sweden. Our findings suggest that this reduction is due to an effective adoptation and adherence to the established risk management plan that implies switching patients at increased PML risk from NTZ to other highly efficacious therapies. A less pronounced decline in PML incidence has recently been observed in France, but not globally.

Improving risk‐stratification of natalizumab‐associated PML

Based on publicly available data, we reevaluated current algorithms for stratifying the risk of progressive multifocal leukoencephalopathy (PML) in natalizumab‐treated patients with multiple sclerosis, and found that there are a number of issues. First and foremost, our analysis highlights the necessity of separate PML incidence assessments for the U.S. versus Europe, and indicates that the risk in John Cunningham virus (JCV) antibody‐negative patients may be higher than previously communicated. Additionally, we advocate introducing a low‐risk JCV index threshold of 0.45 for individuals with prior exposure to an immunosuppressant, and setting the low‐risk threshold at 0.6 instead of 0.9 for those without such pretherapies. On the other hand, the risk of PML on natalizumab, in general, appears to not only plateau but to actually decrease after about 5 years of continuous dosing.

Natalizumab-associated progressive multifocal leukoencephalopathy (PML) in multiple sclerosis (MS): \u201ca case report from Ireland with review of literature, clinical pitfalls and future direction\u201d

BackgroundProgressive multifocal leukoencephalopathy (PML) is one of the most serious treatment-related complications that is encountered in patients with multiple sclerosis (MS). PML is a serious complication of MS treatment which is most commonly related to natalizumab.Case presentationWe report clinical course of progressive multifocal leukoencephalopathy (PML) in a 40-year-old man who was on treatment for highly active relapsing-remitting multiple sclerosis with natalizumab (Nz). He was treated with steroids, cidofovir, and mirtazapine and went on to develop long-term disability. The case describes the evolution of PML from diagnosis up till 5 months with changes on sequential brain scans and clinical symptoms in our patient.ConclusionPatients who are on natalizumab should be aware and consented for the risk of PML. They should be periodically re-assessed for their relative PML risk. There is a growing body of evidence that suggests switching patients from natalizumab who have a higher risk of PML to other safer treatment options.

No evidence for loss of natalizumab effectiveness with every-6-week dosing: a propensity score–matched comparison with every-4-week dosing in patients enrolled in the Tysabri Observational Program (TOP)

Background:Extended interval dosing of natalizumab is associated with significantly lower progressive multifocal leukoencephalopathy risk compared with every-4-week (Q4W) dosing in patients with relapsing-remitting multiple sclerosis. Previous studies have suggested that natalizumab effectiveness is maintained in patients who switch from Q4W to extended interval dosing but have been limited by a lack of well-matched patient cohorts.Methods:Tysabri Observational Program (TOP) data as of November 2019 were used to identify patients with relapsing-remitting multiple sclerosis treated with natalizumab Q4W and those with a single physician-indicated dosing change from Q4W to every-6-week (Q6W) dosing after ⩾1 year of Q4W treatment. Patients were propensity score matched at the time of the switch from Q4W to Q6W dosing. Clinical outcomes (annualized relapse rate and probability of remaining relapse free or free of 24-week confirmed disability worsening) and safety outcomes were assessed for the two cohorts.Results:This study included 219 pairs of propensity score–matched Q6W and Q4W patients. Annualized relapse rates were similar for Q6W (0.150) and Q4W (0.157) patients. The probability of remaining relapse free [hazard ratio = 1.243 (95% confidence interval = 0.819–1.888); p = 0.307] and of remaining free of 24-week confirmed disability worsening [hazard ratio = 0.786 (95% confidence interval = 0.284–2.176); p = 0.644] did not differ significantly between Q6W and Q4W patients. Summarized safety results for the matched Q6W and Q4W patients are also presented.Conclusion:These real-world findings in well-matched patient cohorts from TOP demonstrate that natalizumab effectiveness is maintained in patients who switch to Q6W dosing after ⩾1 year of Q4W dosing.ClinicalTrials.gov identifier:NCT00493298

Progressive multifocal leukoencephalopathy and the spectrum of JC virus-related disease.

Progressive multifocal leukoencephalopathy (PML) is a devastating CNS infection caused by JC virus (JCV), a polyomavirus that commonly establishes persistent, asymptomatic infection in the general population. Emerging evidence that PML can be ameliorated with novel immunotherapeutic approaches calls for reassessment of PML pathophysiology and clinical course. PML results from JCV reactivation in the setting of impaired cellular immunity, and no antiviral therapies are available, so survival depends on reversal of the underlying immunosuppression. Antiretroviral therapies greatly reduce the risk of HIV-related PML, but many modern treatments for cancers, organ transplantation and chronic inflammatory disease cause immunosuppression that can be difficult to reverse. These treatments — most notably natalizumab for multiple sclerosis — have led to a surge of iatrogenic PML. The spectrum of presentations of JCV-related disease has evolved over time and may challenge current diagnostic criteria. Immunotherapeutic interventions, such as use of checkpoint inhibitors and adoptive T cell transfer, have shown promise but caution is needed in the management of immune reconstitution inflammatory syndrome, an exuberant immune response that can contribute to morbidity and death. Many people who survive PML are left with neurological sequelae and some with persistent, low-level viral replication in the CNS. As the number of people who survive PML increases, this lack of viral clearance could create challenges in the subsequent management of some underlying diseases.

High anti-JCPyV serum titers coincide with high CSF cell counts in RRMS patients

Background: Progressive multifocal leukoencephalopathy (PML) can in rare cases occur in natalizumab-treated patients with high serum anti-JCPyV antibodies, hypothetically due to excessive blockade of immune cell migration. Objective: Immune cell recruitment to the central nervous system (CNS) was assessed in relapsing-remitting multiple sclerosis (RRMS) patients stratified by low versus high anti-JCPyV antibody titers as indicator for PML risk. Methods: Cerebrospinal fluid (CSF) cell counts of 145 RRMS patients were quantified by flow cytometry. Generalized linear models were employed to assess influence of age, sex, disease duration, Expanded Disability Status Scale (EDSS), clinical/radiological activity, current steroid or natalizumab treatment, as well as anti-JCPyV serology on CSF cell subset counts. Results: While clinical/radiological activity was associated with increased CD4, natural killer (NK), B and plasma cell counts, natalizumab therapy reduced all subpopulations except monocytes. With and without natalizumab therapy, patients with high anti-JCPyV serum titers presented with increased CSF T-cell counts compared to patients with low anti-JCPyV serum titers. In contrast, PML patients assessed before (n = 2) or at diagnosis (n = 5) presented with comparably low CD8 and B-cell counts, which increased after plasma exchange (n = 4). Conclusion: High anti-JCPyV indices, which could be indicative of increased viral activity, are associated with elevated immune cell recruitment to the CNS. Its excessive impairment in conjunction with viral activity could predispose for PML development.

John Cunningham Virus Status, Seroconversion Rate, and the Risk of Progressive Multifocal Leukoencephalopathy in Polish John Cunningham Virus-Seronegative Patients with Relapsing-Remitting Multiple Sclerosis

Introduction: Presence of anti-JC-virus antibodies (JCVAbs) is associated with the increased risk of natalizumab (NAT)-related progressive multifocal leukoencephalopathy (PML). Little is known about seroconversion rate and time to seroconversion in relapsing-remitting multiple sclerosis (RRMS) patients treated with NAT in Poland. The aim of the study was to assess the true risk of PML, seroconversion rate, and time to seroconversion in all JCVAb-negative RRMS patients treated with NAT in Poland. Methods: Demographic and clinical data of all Polish RRMS patients treated with NAT reimbursed by National Health Fund (NFZ) were prospectively collected in electronic files using the Therapeutic Programme Monitoring System provided by NFZ. The assessment of JCVAb presence (without collection of JCVAb index value) in serum (Unilabs, STRATIFY JCV: anti-JCV antibody ELISA) was done at the beginning of therapy and then repeated every 6 months. The maximum follow-up time was 4 years. In Poland, since 2013, according to the NFZ drug program guidance, only patients with negative JCVAb test have started treatment with NAT. Results: In all Polish multiple sclerosis centers, 210 negative JCVAb RRMS patients with at least 9 (±3) months of observation (146 females, 64 males, and the median age at baseline: 33 years) were included in the study. During the follow-up period, JCVAb status changed from negative to positive in 34 patients (16.2%). For half of the patients, the seroconversion was diagnosed 1 year after starting NAT treatment. In 4 patients (1.9%) during follow-up, JCVAb status changed again from positive to negative. In Poland, before establishment of NFZ drug program, 4 cases of PML in patients treated with NAT in clinical trials were diagnosed. In the NFZ drug program, since 2013, no patient treated with NAT has been diagnosed with PML. Conclusions: NAT therapy in JCV-seronegative RRMS patients is safe and results in the absence of PML cases. In Poland, JCV seroconversion rate is similar to that observed in other European countries.

Author response: Prospective validation of the PML risk biomarker l -selectin and influence of natalizumab extended intervals

On behalf of all authors, we would like to thank Mr. Tugemann for his interest in our article.1 It is correct that acute progressive multifocal leukoencephalopathy (PML) can, in some circumstances, lead to high(er) CD62L values. However, as the study was conducted prospectively and, more importantly, alongside treatment, we reported all results of samples shipped to us back to the treating physicians. At the time of measurement and reporting, we were not aware of the patients' disease state. Because this is the situation to be expected in postmarketing settings, we chose to report all measured values, even if the samples turned out to be less than 6 months before PML diagnosis. Although the exclusion of these samples would indeed have led to a perfect sensitivity with the threshold of 36.05, we believed that it would not accurately reflect the real-world situation. Similarly, we chose not to focus on other PML risk stratification factors such as previous immune suppression or anti-JC virus antibody serostatus because we could not rely on having this information for all samples shipped to us. We, therefore, decided to report on the feasibility of measuring one biomarker rather than presenting a holistic approach for risk stratification using all available markers, which was addressed before.2 As supported by this study, CD62L was proven to be a useful biomarker for PML risk stratification also in the real-world setting but could also help with monitoring immunologic changes because of natalizumab-extended interval dosing. Owing to its initial detection in a retrospective cohort, the validated methodology3 still requires a mandatory freeze/thaw cycle, thereby limiting its widespread use. However, we would be more than happy if methodological improvements could be achieved here.

Reader response: Prospective validation of the PML risk biomarker l-selectin and influence of natalizumab extended intervals.

With great interest I read the article by Schwab et al.1 on the risk of natalizumab-associated progressive multifocal leukoencephalopathy (PML) as a function of CD62L-expression. However, for the statistical analyses, unlike in earlier studies,2,3 the authors also took blood samples drawn at diagnosis into account. Given that CD62L often increases during the acute stage of PML,2 this may have adversely affected the marker's estimated sensitivity. Another bias was presumably introduced through the inclusion of patients who were JC virus (JCV)-seronegative, disregarding that the latter have a substantially lower risk,4 which is relevant because expression of CD62L in fact negatively correlates with JCV antibody titers.3 Therefore, it would have been more clinically meaningful to restrict the assessments to users of natalizumab who were JCV-seropositive, and, for those developing PML, to samples obtained at least 6 months before the outbreak—cf. Biogen's risk stratification by JCV-index.4,5 In addition, it might be informative to have a chart showing the temporal evolution of CD62L for all patients with PML in the cohort (how long before diagnosis each available value was measured—cf. again work by the drugmaker5). The 2 outliers—with minimum expression in the range of 50%–60% and thus well above the median1—seem to impair the predictive power of the test. Finally, Schwab et al. remarked that the methodology “currently” limited widespread usage of their assay,1 suggesting that this may change in the future. It would be helpful to have further detail on this.

HIV-1 acquisition in a man with ulcerative colitis on anti-α4β7 mAb vedolizumab treatment.

HIV-1 acquisition in a man with ulcerative colitis on anti-α4β7 mAb vedolizumab treatment.

Archetype JC polyomavirus DNA associated with extracellular vesicles circulates in human plasma samples.

JC polyomavirus (JCPyV) establishes a stable and successful interaction with the host, causing progressive multifocal leukoencephalopathy (PML) in immunocompromised subjects. Recently, it has been reported that JCPyV, like other viruses, may exploit extracellular vesicles (EV) in cell cultures. To investigate the presence of JCPyV-DNA in EV circulating in human plasma obtained from patients at risk for PML. JCPyV-DNA status was studied in EV obtained from 170 plasma samples collected from 120 HIV positive patients and 50 healthy donors. EV were extracted from plasma and characterized by Nanoparticle tracking analysis, by western blot for presence of tetraspanin CD63, CD81, annexin II, cythocrome C protein and, finally, by immunoelectron microscopy (IEM). Presence and quantitation of JCPyV-DNA were assessed with Multiplex real-time TaqMan PCR assay. The JCPyV-DNA plasma prevalence in 120 HIV positive patients and 50 healthy donors was 28% and 4%, respectively. The investigation performed on well-characterized plasma EV reported JCPyV-DNA detection in 15 out of 36 (42%) of the viremic samples (14 were from HIV patients and 1 from healthy people) at a mean level of 23.5 copies/mL. The examination of EV selected samples reported the percentage of JCPyV-DNA in EV of 5.4% of the total viral load. Moreover, IEM reported the presence of JCPyV Vp1 antigen in plasma-derived EV. The potential role of EV-associated JCPyV-DNA open new avenues and mechanistic insights into the molecular strategies adopted by this polyomavirus to persist in the host and spread to the central nervous system.

Natalizumab extended interval dosing (EID) is associated with a reduced risk of progressive multifocal leukoencephalopathy (PML) than every-4-week (Q4W) dosing: Updated analysis of the TOUCH® Prescribing Program database (1988)

Natalizumab extended interval dosing (EID) is associated with a reduced risk of progressive multifocal leukoencephalopathy (PML) than every-4-week (Q4W) dosing: Updated analysis of the TOUCH® Prescribing Program database (1988)

Changes in Anti-JCV Antibody Status in a Large Population of Multiple Sclerosis Patients Treated with Natalizumab.

Natalizumab (NTZ) can be associated with an opportunistic infection, progressive multifocal leukoencephalopathy (PML), caused by John Cunningham virus (JCV). High titer of anti-JCV antibody (JCV index) in patients treated with NTZ for over 2 years limit it use, leading to treatment discontinuation. Aim of the study was to investigate the JCV index changes pre, during and post NTZ treatment and describe the trend after a long period of NTZ discontinuation. Patients with relapsing-remitting multiple sclerosis (RR-MS) treated with NTZ between 2010 and 2018 were enrolled in this retrospective-prospective observational study. Inclusion criteria were: (1) diagnosis of RR-MS according to the McDonald criteria 2010, (2) at least six NTZ administrations, (3) at least two determinations of JCV Index during the follow-up period, (4) NTZ discontinuation period for more than 6 months. JCV index was determined by STRATIFY II. There were three different timepoints: NTZ initiation (T0), NTZ discontinuation (T1) and time after NTZ suspension (T2). Seroconversion was defined as changing status of serum JCV antibody. Main outcomes were the JCV index changes and the rate of seroconversion. At baseline we enrolled 285 patients (208 JCV negative, 67 JCV positive, and 10 not available). There was a statistically significant increase of JCV index during NTZ treatment period (T0 vs T1, p =0.0009) and during NTZ discontinuation period (T1 vs T2, p =0.04). Patients seroconverted to a positive status more frequently during NTZ treatment than after discontinuation (p =0.008). Moreover, patients who shifted to fingolimod (FTY) as exit strategy after NTZ discontinuation, showed a statistically significant increase of JCV index. Our data confirmed that a high percentage of patients shift to or remain in a positive JCV status during NTZ treatment and after discontinuation. NTZ suspension seems not to be able to interfere on JCV status modification over an extended period. The choice of alternative treatment as exit strategy after NTZ discontinuation should be carefully considered because it could negatively influence the PML risk stratification of patients.

A Study of the John Cunningham Virus (JCV) Seroprevalence among Zambian Adults presenting with “Meningoencephalitis” to the University Teaching Hospital, Lusaka, Zambia

Background:&#x0D; The John Cunningham virus (JCV) is an opportunistic virus which leads to the development of progressive multifocalleukoencephalopathy (PML), which is a lytic infection of oligodendrocytes of the central nervous system in immunosuppressed patients. Infection with the JCV occurs in childhood and the virus remains quiescent in the body, activating during immunosuppression. Exposure to the virus can be detected by testing for JC virus specific antibodies inan ELISA test. Our aim was to determine the JCV seroprevalence and factors associated with its positivity among Zambian adults presenting to the University Teaching Hospital (UTH) with suspected meningoencephalitis and to assess the JCV ELISA test as a possible tool for PML risk stratification.&#x0D; Methodology:&#x0D; This was a cross sectional nested study in the TB meningitis in Zambia (TMZ) study which looked at improving ways of TB diagnosis in patients with meningoencephalitis. It included adults 18 years and older who presented with suspected meningoencephalitis and had undergone a lumbar puncture as part of their evaluation. 50 HIV positive and 50 HIV negative patients were selected from the parent study and underwent testing for JCV serology. PML cases were also recruited from the parent study based on clinical features, confirmed by JCV DNA PCR of CSF.&#x0D; Results:&#x0D; Final analysis for JCV seroprevalence was done in 96 patients and noted to be 46% (95% CI, 35.62 – 56.31). The JCV seroprevalence in the HIV positive group was 40.82% and in the HIV negative group was 51.06 % but there was no statistical difference (p-value 0.31). None of the other factors studied had any impact on the JCV seroprevalencesuch as age, gender, clinical presentation, CD4 count and co-morbid TB meningitis (TBM) diagnosis. There was a bimodal distribution of age associated with JCV seropositivity; with one peak occurring in the 18 to 20 years age group and thesecond peak occurring in the 55 to 60 years age group. 14 (3.2%) confirmed PML cases, based on clinical features and JCV DNA CSF positive, were all JCV seropositive and HIV positive with advanced immunosuppression (CD4&lt;200/mm3).Memory impairment was associated with a 6 fold increased likelihood of having PML in advanced HIV disease with JCV seropositive patients which further, increased to over 20 fold after adjusting for age , gender and TBM diagnosis. After adjusting for other variables TBM was associated with an 87% less likelihood of having PML (p-value 0.03).Female gender was associated with increased risk of having PML (p-value 0.02) and a younger age was protective for PML (p-value 0.03).&#x0D; Conclusion:&#x0D; The prevalence of anti-JCV antibodies in patients with suspected CNS infection (meningoencephalitis) was 46%. Anti- JCVantibody prevalence did not differ significantly by age, gender, HIV status or CD4 count. Memory impairment in JCV seropositive, advanced HIV disease patients with meningoencephalitis was the most important variable associated with having PML.

Germline Genetic Risk Variants for Progressive Multifocal Leukoencephalopathy.

Progressive multifocal leukoencephalopathy (PML) is a rare demyelinating disorder of the brain caused by reactivation of the JC virus (JCV), a polyomavirus that infects at least 60% of the population but is asymptomatic or results in benign symptoms in most people. PML occurs as a secondary disease in a variety of disorders or as a serious adverse event from immunosuppressant agents, but is mainly found in three groups: HIV-infected patients, patients with hematological malignancies, or multiple sclerosis (MS) patients on the immunosuppressant therapy natalizumab. It is severely debilitating and is deadly in ~50% HIV cases, ~90% of hematological malignancy cases, and ~24% of MS-natalizumab cases. A PML risk prediction test would have clinical utility in all at risk patient groups but would be particularly beneficial in patients considering therapy with immunosuppressant agents known to cause PML, such as natalizumab, rituximab, and others. While a JC antibody test is currently used in the clinical decision process for natalizumab, it is suboptimal because of its low specificity and requirement to periodically retest patients for seroconversion or to assess if a patient's JCV index has increased. Whereas a high specificity genetic risk prediction test comprising host genetic risk variants (i.e., germline variants occurring at higher frequency in PML patients compared to the general population) could be administered one time to provide clinicians with additional risk prediction information that is independent of JCV serostatus. Prior PML case reports support the hypothesis that PML risk is greater in patients with a genetically caused immunodeficiency disorder. To identify germline PML risk variants, we performed exome sequencing on 185 PML cases (70 in a discovery cohort and 115 in a replication cohort) and used the gnomAD variant database for interpretation. Our study yielded 19 rare variants (maximum allele frequency of 0.02 in gnomAD ethnically matched populations) that impact 17 immune function genes (10 are known to cause inborn errors of immunity). Modeling of these variants in a PML genetic risk test for MS patients considering natalizumab treatment indicates that at least a quarter of PML cases may be preventable.

Which is the best PML risk stratification strategy in natalizumab-treated patients affected by multiple sclerosis?

BackgroundThe risk of progressive multifocal leukoencephalopathy (PML), a brain infection caused by John Cunningham virus (JCPyV), is the main limitation to the use of natalizumab, highly effective in the treatment of relapsing remitting multiple sclerosis (RRMS) patients. Establishing the PML risk against expected benefits represents an obligatory requirement of MS treatment algorithm. In order to achieve this goal, the aims of this study were to establish if JCPyV-DNA detection and non-coding control region (NCCR) arrangements could play a role of biomarkers, supporting anti-JCPyV antibodies measurement, actually the only parameter for PML risk stratification. MethodsThirty RRMS patients in treatment with natalizumab were enrolled. Urine and blood samples were collected according to this calendar: baseline (T0), 4 (T1), 8 (T2), 12 (T3), 16 (T4), 20 months (T5) after beginning of natalizumab therapy. After JCPyV DNA extraction, a specific quantitative-PCR (Q-PCR) and arrangements’ analysis of NCCR and Viral Capsid Protein 1 (VP1) were carried out. ResultsQ-PCR detected JCPyV DNA in urine and blood from baseline (T0) to 20 natalizumab infusions (T5), although JC viral load in urine was significantly higher compared to viremia, at all selected time points. A contextual analysis of the anti-JCPyV-antibodies versus JCPyV-DNA detection revealed that viral DNA preceded the antibodies’ presence in the serum. During the first year of natalizumab treatment, sequences isolated from blood displayed an archetype JCPyV NCCR structure with the occurrence of point mutations, whereas after one year NCCR re-organizations were observed in plasma and PBMC with duplication of NF-1 binding site in box F, duplication of box C and partial or total deletion of box D. VP1 analysis showed the amino acid change mutation S269F in plasma and S267L in PBMC, involving the receptor-binding region of VP1. Phylogenetic analysis suggested a stability and a similarity across different isolates of the JCPyV VP1. ConclusionsWe highly recommend considering JCPyV-DNA detection and NCCR re-organizations as viral biomarkers in order to accurately identify JCPyV-infected patients with a specific humoral response not yet detectable and to identify NCCR arrangements correlated with the onset of neurovirulent variants.

JCPyV NCCR analysis in PML patients with different risk factors: exploring common rearrangements as essential changes for neuropathogenesis

BackgroundDuring severe immunosuppression or treatment with specific biological drugs, human polyomavirus JC (JCPyV) may establish a lytic infection in oligodendrocytes, leading to progressive multifocal leukoencephalopathy (PML). Beyond AIDS, which represents the most common predisposing condition, several biological drugs have been associated to the development of PML, such as natalizumab, fingolimod and dimethyl fumarate, which have been showed to increase the risk of PML in the multiple sclerosis (MS) population. JCPyV non-coding control region (NCCR) can be found in two different forms: a virulent neurotropic pathogenic form and a latent non-pathogenic form. The neurotropic forms contain a rearranged NCCR and are typically found in the cerebrospinal fluid, brain or blood of PML patients.Case presentationWe sequenced and critically examined JCPyV NCCR from isolates detected in the cerebrospinal fluid of four newly diagnosed progressive multifocal leukoencephalopathy patients: two HIV-positive and two HIV-negative multiple sclerosis patients. More complex NCCR rearrangements were observed in the two HIV-positive patients compared to the HIV-negative multiple sclerosis patients with PML.ConclusionsThe comparison of HIV-positive and HIV-negative MS patients with PML, allowed us to evidence the presence of a common pattern of JCPyV NCCR rearrangement, characterized by the deletion of the D-block, which could be one of the initial rearrangements of JCPyV NCCR needed for the development of PML.

Natalizumab-associated progressive multifocal leukoencephalopathy in patients with multiple sclerosis: risk reduction, management and possibilities for subsequent immunoregulation

The risk of progressive multifocal leukoencephalopathy (PML) is one of the factors limiting the widespread use of natalizumab (NTZ). As a strategy for potentially reducing the frequency of the NTZ-associated PML, while maintaining the high therapy efficacy, in addition to the widely-used risk stratification strategy based on anti-JC virus antibody index and therapy duration, we propose the administration of NTZ with an extended dosing interval. Opinions vary on the effectiveness of plasmapharesis in confirmed cases of PML. The most challenging problem is how to manage patients, who develop PML, and what MS disease-modifying therapy should be considered for the subsequent use.