JC-virus seroconversion in multiple sclerosis patients receiving natalizumab

Positive Association Between the Immunogenetic Human Leukocyte Antigen (HLA) Profiles of Multiple Sclerosis and Brain Cancer

Previous research has documented elevated risk of brain cancer in patients with multiple sclerosis (MS). Separately, human leukocyte antigen (HLA) has been implicated in protection or susceptibility for both conditions. The aim of the current study was to assess a possible role of shared immunogenetic influence on risk of MS and brain cancer. We first identified an immunogenetic profile for each condition based on the covariance between the population frequency of 127 high-resolution HLA alleles and the population prevalence of each condition in 14 Continental Western European countries and then evaluated the correspondence between MS and brain cancer immunogenetic profiles. Also, since each individual carries 12 HLA alleles (2 × 6 genes), we estimated HLA protection and susceptibility for MS and brain cancer at the individual level. We found that the immunogenetic profiles of MS and brain cancer were highly correlated overall (P < .001) and across all 6 HLA genes with the strongest association observed for DRB1, followed by DQB1 and HLA-A. These findings of immunogenetic overlap between MS and brain cancer are discussed in light of the role of HLA in the immune system response to viruses and other foreign antigens.

Co-occurrence of glioma and multiple sclerosis: Prevailing theories and emerging therapies

Though the concurrence of primary brain tumors and multiple sclerosis (MS) is exceedingly rare, instances have been noted in the literature as early as 1949. Given these observations, researchers have proposed various ideas as to how these malignancies may be linked to MS. Due to insufficient data, none have gained traction or been widely accepted amongst neurologists or neuro-oncologists. What is abundantly clear, however, is the mounting uncertainty faced by clinicians when caring for these individuals. Concerns persist about the potential for disease modifying therapies (DMTs) to initiate or promote tumor growth and progression, and to date, there are no approved treatments capable of mitigating both MS disease activity and tumor growth, let alone established guidelines that clinicians may refer to. Collectively, these gaps in the literature impose limitations to optimizing the care and management of this population. As such, our hope is to stimulate further discussion of this topic and prompt future investigations to explore novel treatment options and advance our understanding of these concurrent disease processes. To this end, the chief objective of this article is to evaluate proposed ideas of how the diseases may be linked, outline emerging therapies for both MS and brain tumors, and describe evidence-based approaches to diagnosing and treating this patient population.

Negative association between multiple sclerosis immunogenetic profile and in silico immunogenicities of 12 viruses

Human Leukocyte Antigen (HLA) is involved in both multiple sclerosis (MS) and immune response to viruses. Here we investigated the virus-HLA immunogenicity (V-HLA) of 12 viruses implicated in MS with respect to 17 HLA Class I alleles positively associated to MS prevalence in 14 European countries. Overall, higher V-HLA immunogenicity was associated with smaller MS-HLA effect, with human herpes virus 3 (HHV3), JC human polyoma virus (JCV), HHV1, HHV4, HHV7, HHV5 showing the strongest association, followed by HHV8, HHV6A, and HHV6B (moderate association), and human endogenous retrovirus (HERV-W), HHV2, and human papilloma virus (HPV) (weakest association). These findings suggest that viruses with proteins of high HLA immunogenicity are eliminated more effectively and, consequently, less likely to be involved in MS.

Multiple sclerosis-disease modifying therapies affect humoral and T-cell response to mRNA COVID-19 vaccine

Background

The mRNA vaccines help protect from COVID-19 severity, however multiple sclerosis (MS) disease modifying therapies (DMTs) might affect the development of humoral and T-cell specific response to vaccination.

Methods

The aim of the study was to evaluate humoral and specific T-cell response, as well as B-cell activation and survival factors, in people with MS (pwMS) under DMTs before (T0) and after two months (T1) from the third dose of vaccine, comparing the obtained findings to healthy donors (HD). All possible combinations of intracellular IFNγ, IL2 and TNFα T-cell production were evaluated, and T-cells were labelled "responding T-cells", those cells that produced at least one of the three cytokines of interest, and "triple positive T-cells", those cells that produced simultaneously all the three cytokines.

Results

The cross-sectional evaluation showed no significant differences in anti-S antibody titers between pwMS and HD at both time-points. In pwMS, lower percentages of responding T-cells at T0 (CD4: p=0.0165; CD8: p=0.0022) and triple positive T-cells at both time-points compared to HD were observed (at T0, CD4: p=0.0007 and CD8: p=0.0703; at T1, CD4: p=0.0422 and CD8: p=0.0535). At T0, pwMS showed higher plasma levels of APRIL, BAFF and CD40L compared to HD (p<0.0001, p<0.0001 and p<0.0001, respectively) and at T1, plasma levels of BAFF were still higher in pwMS compared to HD (p=0.0022).According to DMTs, at both T0 and T1, lower anti-S antibody titers in the depleting/sequestering-out compared to the enriching-in pwMS subgroup were found (p=0.0410 and p=0.0047, respectively) as well as lower percentages of responding CD4+ T-cells (CD4: p=0.0394 and p=0.0004, respectively). Moreover, the depleting/sequestering-out subgroup showed higher percentages of IFNγ-IL2-TNFα+ T-cells at both time-points, compared to the enriching-in subgroup in which a more heterogeneous cytokine profile was observed (at T0 CD4: p=0.0187; at T0 and T1 CD8: p =0.0007 and p =0.0077, respectively).

Conclusion

In pwMS, humoral and T-cell response to vaccination seems to be influenced by the different DMTs. pwMS under depleting/sequestering-out treatment can mount cellular responses even in the presence of a low positive humoral response, although the cellular response seems qualitatively inferior compared to HD. An understanding of T-cell quality dynamic is needed to determine the best vaccination strategy and in general the capability of immune response in pwMS under different DMT.

Longitudinal stability of JCV antibody index in Natalizumab treated people with multiple sclerosis

OBJECTIVE

The aim of this study was to evaluate the evolution of JCV index over time in Natalizumab treated people with multiple sclerosis.

MATERIALS AND METHODS

We retrospectively reviewed antibody index values from pwMS who were treated with Natalizumab for greater than six months and had at least two antibody results available between 2011 and 2019. Survival analysis was performed on those who were JCV index value negative at baseline to evaluate time to seroconversion. In pwMS who had index values available at 48 and/or 96 months post Natalizumab initiation, t-tests were performed to evaluate change in index over time.

RESULTS

1144 JCV antibody index results were available for 132 pwMS. Median time to seroconversion based on survival analysis was 103 months. Annualised seroconversion rate was 5.8%. Initial antibody index and rate of seroconversion did not differ with regards to age or gender. Antibody index increased significantly over time on treatment for the cohort as a whole, initial antibody index (0.27) to final antibody testing (0.86), t(131)=6.45, p<.0005. There was a significant increase in those with initial positive index value, between first (0.95) and final index (2.14), t(33) = 4.85, p<.0005 over a median of 77 months.

CONCLUSIONS

In those who were seronegative at baseline there is a long median duration of treatment with Natalizumab prior to seroconversion. In individuals with positive JCV antibody index at treatment initiation, antibody index increases over time.

Laboratory biomarkers of Multiple Sclerosis (MS)

Multiple Sclerosis (MS) is a neurological disease that affects the central nervous system (CNS). The diagnosis of the disease is quite challenging due to its variation among patients. As a result, the need to enhance diagnostic procedures, evaluate objective prognostic markers and promote effective monitoring of patients' responses to treatment has prompted the identification of many biomarkers. To present up-to-date knowledge on potential biomarkers for MS used to assess disease activity, progression, and therapeutic responses. The search for articles was conducted in various databases, namely, PubMed, Cochrane Library, and CINAHL, using an identical search strategy and terms that included "Multiple Sclerosis," "MS," "biomarkers," "potential," "magnetic resonance spectroscopy," "progress," "marker," "predict," "disability," "indicator," and "mass spectrometry." Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines were followed when scrutinizing the articles for inclusion in the study. The search process identified 75 articles that were used in this systematic review. MS biomarkers consisted of laboratory biomarkers, imaging biomarkers, and genetic and immunogenetic biomarkers. The efficacy, which leads to their potential classification, relies on numerous factors, such as sensitivity, specificity, clinical rationale, predictability, practicality, biological rationale, reproducibility, and correlations with prognosis and disability. Oligoclonal bands (OCBs) and magnetic resonance imaging (MRI) features are the most established biomarkers so far, although kappa free light chains (kFLCs), the measles-rubella-zoster (MRZ) reaction, and neurofilament light chains (NfLs) might show potential in the near future after more studies are conducted.

Patient and treatment characteristics and safety outcomes of patients with relapsing-remitting multiple sclerosis treated with natalizumab in Greece: Results from the multicenter, 5-year prospective observational study 'TOPICS greece'

Background

Natalizumab is a highly efficacious treatment for relapsing-remitting multiple sclerosis (RRMS).

Objective

To assess the real-world long-term safety of natalizumab in RRMS.

Methods

This multicenter, 5-year prospective observational study, included adults with RRMS newly initiated on natalizumab as per the approved product label in the routine care in Greece. Safety was evaluated by collecting serious adverse events (SAEs) following study enrollment.

Results

Between 19-Apr-2012 and 18-Dec-2014, 304 eligible patients (median age at natalizumab initiation: 38.0 years; median disease duration: 6.2 years) were enrolled by 20 hospital-based neurologists. Over a median treatment duration period of 58.7 months, 50.7% of the patients discontinued natalizumab, mainly due to anti-JCV antibody detection (59.1%). The adverse event treatment discontinuation rate was 5.2%. The SAE incidence rate during the safety data collection period (median: 48.7 months) was 4.6%. The most common SAEs were infections (1.0%), including 2 cases (0.7%) of progressive multifocal leukoencephalopathy (PML), and no other opportunistic infections. PML diagnoses occurred 6.2-6.7 years after natalizumab initiation, and approximately 2 years after first detection of anti-JCV antibody for both patients. The incidence rate of malignancies was 0.7%.

Conclusion

In real-world settings in Greece, natalizumab displayed an acceptable safety profile, with no new safety signals emerging.

High rates of JCV seroconversion in a large international cohort of natalizumab-treated patients

Aims:

To retrospectively assess factors associated with John Cunningham virus (JCV) seroconversion in natalizumab-treated patients.

Background:

Natalizumab is highly effective for the treatment of relapsing–remitting multiple sclerosis (RRMS), but its use is complicated by opportunistic JCV infection. This virus can result in progressive multifocal leukoencephalopathy (PML). Serial assessment of JCV serostatus is mandated during natalizumab treatment.

Methods:

Patients treated with natalizumab for RRMS at six tertiary hospitals in Melbourne, Australia (n = 865) and 11 MS treatment centres in Brazil (n = 136) were assessed for change in JCV serostatus, duration of exposure to natalizumab and prior immunosuppression. Sensitivity analyses examined whether sex, age, tertiary centre, prior immunosuppression or number of JCV tests affected time to seroconversion.

Results:

From a cohort of 1001 natalizumab-treated patients, durable positive seroconversion was observed in 83 of 345 initially JCV negative patients (24.1%; 7.3% per year). Conversely, 16 of 165 initially JCV positive patients experienced durable negative seroconversion (9.7%; 3.8% per year). Forty patients (3.9%) had fluctuating serostatus. Time-to-event analysis did not identify a relationship between JCV seroconversion and duration of natalizumab exposure. Prior exposure to immunosuppression was not associated with an increased hazard of positive JCV seroconversion. Male sex was associated with increased JCV seroconversion risk [adjusted hazard ratio 2.09 (95% confidence interval 1.17–3.71) p = 0.012].

Conclusion:

In this large international cohort of natalizumab-treated patients we observed an annual durable positive seroconversion rate of 7.3%. This rate exceeds that noted in registration and post-marketing studies for natalizumab. This rate also greatly exceeds that predicted by epidemiological studies of JCV seroconversion in healthy populations. Taken together, our findings support emerging evidence that natalizumab causes off-target immune changes that may be trophic for JCV seroconversion. In addition, male sex may be associated with increased positive JCV seroconversion.

The impact of lymphocytosis and CD4/CD8 ratio on the anti-JCV antibody index and clinical data in patients treated with natalizumab

BACKGROUND

Natalizumab is an effective therapy in the treatment of relapsing-remitting multiple sclerosis; it induces lymphocytosis (NIL, natalizumab-induced lymphocytosis) and changes the peripheral lymphocyte pattern.

METHODS

This study aims to evaluate NIL, peripheral blood lymphocyte subsets, CD4/CD8 ratio, and their impacts on JCV index and clinical data-No Evidence of Disease Activity (NEDA-3) and annualized relapse rate (ARR) in patients treated with natalizumab.

RESULTS

Forty-one patients (33 women) were included in the study. The mean duration of follow-up on natalizumab treatment was 6.7 ± 3.2 years. Significant increases in relative lymphocytosis after 1 month, with a median of 40.4% (- 34.1 to + 145.5%) (p < 0.001), and after 1 year (49.0% (- 9.3 to + 127.6%)) (p < 0.001) were found. Significant differences were found after 1 month when comparing NIL between patients JCV-seroconverting (20.6% (- 17.7 to 72.7%)) and stable JCV-seronegative ones (43.5% (- 6.3 to +96.3%)) (p = 0.04). No significant difference NIL level was found between the patients exhibiting NEDA-3 status and those without it. ARR on natalizumab treatment correlated with CD4/CD8 ratio (r = 0.356; p = 0.021); patients who maintained NEDA-3 status over the whole treatment period exhibited a lower CD4/CD8 ratio (1.89 ± 1.08 vs. 2.5 ± 0.73; p < 0.04).

CONCLUSION

This contribution reports the CD4/CD8 ratio as a possible biomarker for better clinical efficacy of natalizumab in patients exhibiting a lower CD4/CD8 ratio. NIL did not correlate with long-term therapeutic efficacy in patients treated with natalizumab, but was demonstrated as lower in patients JCV-seroconverting in the course of follow-up.

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.

Long-term effect of natalizumab in patients with RRMS: TYSTEN cohort

BACKGROUND

Data are needed on long-term effect of natalizumab (NTZ) in relapsing-remitting multiple sclerosis (RRMS).

OBJECTIVES

To evaluate the time of onset of secondary progressive phase in patients with an RRMS treated with NTZ and to investigate predictive factors.

METHODS

TYSTEN is an observational study. Patients starting NTZ between 2007 and 2012 were included and followed up until October 2018. Relapses, Expanded Disability Status Scale (EDSS) scores, and results of brain magnetic resonance imaging (MRI) were collected each year. Data were used to estimate the cumulative probability of several poor outcomes such as secondary progressive multiple sclerosis (SPMS) conversion, EDSS worsening, EDSS 4.0, and EDSS 6.0.

RESULTS

770 patients were included. The mean follow-up duration was 97 months and the mean time exposure to NTZ was 66 months. At 10 years, the cumulative probability of SPMS was 27.7%. Predictive factors for poor outcomes were a ⩾1-point increase in EDSS score from baseline, new T2 lesion or T1 gadolinium-enhancing lesion, the occurrence of relapse at 1 or 2 years and No Evidence of Disease Activity (NEDA-3; no relapse, no new T2 or T1 gadolinium-enhancing lesions, no progression) was a protective factor.

CONCLUSION

In our cohort of patients treated with NTZ, poor outcomes were infrequent and are driven by disease activity.

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

INTRODUCTION

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.

OBJECTIVE

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

MicroRNAs as disease progression biomarkers and therapeutic targets in experimental autoimmune encephalomyelitis model of multiple sclerosis

Multiple sclerosis is an autoimmune neurodegenerative disease of the central nervous system characterized by pronounced inflammatory infiltrates entering the brain, spinal cord and optic nerve leading to demyelination. Focal demyelination is associated with relapsing-remitting multiple sclerosis, while progressive forms of the disease show axonal degeneration and neuronal loss. The tests currently used in the clinical diagnosis and management of multiple sclerosis have limitations due to specificity and sensitivity. MicroRNAs (miRNAs) are dysregulated in many diseases and disorders including demyelinating and neuroinflammatory diseases. A review of recent studies with the experimental autoimmune encephalomyelitis animal model (mostly female mice 6–12 weeks of age) has confirmed miRNAs as biomarkers of experimental autoimmune encephalomyelitis disease and importantly at the pre-onset (asymptomatic) stage when assessed in blood plasma and urine exosomes, and spinal cord tissue. The expression of certain miRNAs was also dysregulated at the onset and peak of disease in blood plasma and urine exosomes, brain and spinal cord tissue, and at the post-peak (chronic) stage of experimental autoimmune encephalomyelitis disease in spinal cord tissue. Therapies using miRNA mimics or inhibitors were found to delay the induction and alleviate the severity of experimental autoimmune encephalomyelitis disease. Interestingly, experimental autoimmune encephalomyelitis disease severity was reduced by overexpression of miR-146a, miR-23b, miR-497, miR-26a, and miR-20b, or by suppression of miR-182, miR-181c, miR-223, miR-155, and miR-873. Further studies are warranted on determining more fully miRNA profiles in blood plasma and urine exosomes of experimental autoimmune encephalomyelitis animals since they could serve as biomarkers of asymptomatic multiple sclerosis and disease course. Additionally, studies should be performed with male mice of a similar age, and with aged male and female mice.

Progressive Multifocal Leukoencephalopathy: Current Insights

Cases of PML should be evaluated according to predisposing factors, as these subgroups differ by incidence rate, clinical course, and prognosis. The three most significant groups at risk of PML are patients with hematological malignancies mostly previously treated with immunotherapies but also untreated, patients with HIV infection, and patients using monoclonal antibody (mAb) treatments. Epidemiological data is scarce and partly conflicting, but the distribution of the subgroups appears to have changed. While there is no specific anti-JCPyV treatment, restoration of the immune function is the most effective approach to PML treatment. Research is warranted to determine whether immune checkpoint inhibitors could benefit certain PML subgroups. There are no systematic national or international records of PML diagnoses or a risk stratification algorithm, except for MS patients receiving natalizumab (NTZ). These are needed to improve PML risk assessment and to tailor better prevention strategies.

Incidence of seroconversion and sero-reversion in patients with multiple sclerosis (MS) who had been treated with natalizumab: A systematic review and meta-analysis

BACKGROUND

Natalizumab is a medication of choice for some patients with relapsing remitting (RR) form of multiple sclerosis (MS). John Cunningham virus (JCV) antibody status is important in cases who are treating with natalizumab. Different studies reported various rates of seroconversion and sero-reversion in patients who had been treated with natalizumab. As there is no systematic review reporting incidence of seroconversion and seroreversion in MS cases who were treated with natalizumab, we aimed to conduct this systematic review and meta-analysis to find pooled incidence of seroconversion and seroreversion in MS cases who were treated with natalizumab.

METHODS

PubMed, Scopus, EMBASE, CINAHL, Web of Science, Ovid, and google scholar were systematically searched. We also searched the gray literature including references from included studies, and conference abstracts which were published up to April 2019.

RESULTS

The incidence of seroconversion was reported between 6% and 41% and the incidence of seroreversion was reported between 1% and 11%. The pooled estimate of seroconversion incidence was 19% (95% CI: 13%-25%) (I² = 96.8%, P < 0.001) and the pooled estimate of seroreversion incidence was 5% (95% CI: 3%-8%) (I² = 72.2%, P < 0.001). Subgroup analysis by considering the country of the origin showed that the pooled incidence of seroconversion incidence during the studies was 6% in Asian countries and 21% in European/American countries. The incidence difference between subgroups was significant (p < 0.001).

CONCLUSION

Incidence of seroconversion in MS patients who had been treated with natalizumab is higher in European/American countries than Asian countries.

Serological profile of John Cunningham virus (JCV) in patients with multiple sclerosis

Treatment options for multiple sclerosis (MS) have changed over the last few years, bringing about a new category of drugs with more efficient profiles. However, these drugs have come with a whole new profile of potential adverse events that neurologists have to learn well and quickly. One of the most feared complications of these MS treatments is progressive multifocal leukoencephalopathy caused by the reactivation of the John Cunningham virus (JCV).

OBJECTIVE

To identify the serologic profile of JCV in patients with MS.

METHODS

Data on serum antibodies for JCV were obtained using the enzyme-linked immunosorbent assay provided by the STRATIFY-JCV program.

RESULTS

A total of 1,501 blood tests were obtained from 1,102 patients with MS. There were 633 patients (57.1%) who were positive for antibodies for JCV and 469 patients who were negative (42.9%). Twenty-three patients became positive after initially having negative JCV antibody status. The rate of seroconversion was 18.5% over 22 months.

CONCLUSION

The JCV serologic profile and seroconversion in Brazilian patients were similar to those described in other countries.

Biomarkers in Multiple Sclerosis

Multiple sclerosis (MS) is a chronic neurodegenerative autoimmune disease with a complex clinical course characterized by inflammation, demyelination, and axonal degeneration. Diagnosis of MS most commonly includes finding lesions in at least two separate areas of the central nervous system (CNS), including the brain, spinal cord, and optic nerves. In recent years, there has been a remarkable increase in the number of available treatments for MS. An optimal treatment is usually based on a personalized approach determined by an individual patient's prognosis and treatment risks. Biomarkers that can predict disability progression, monitor ongoing disease activity, and assess treatment response are integral in making important decisions regarding MS treatment. This review describes MS biomarkers that are currently being used in clinical practice; it also reviews and consolidates published findings from clinically relevant potential MS biomarkers in recent years. The work also discusses the challenges of validating and application of biomarkers in MS clinical practice.

The miRNA Expression Profile of Experimental Autoimmune Encephalomyelitis Reveals Novel Potential Disease Biomarkers

Multiple sclerosis (MS) is a debilitating autoimmune disease affecting over 2.3 million people worldwide, and it is characterized by inflammation and demyelination of nerve cells. The currently available biomarkers for the diagnosis and management of MS have inherent limitations, therefore, additional new biomarkers are needed. We studied the microRNA (miRNA) profile of splenocytes of mice having experimental autoimmune encephalomyelitis (EAE), a model of human MS. A miRNA-microarray analysis revealed increased expression of nine miRNAs (let-7e, miR-23b, miR-31, miR-99b, miR-125a, miR-146b, miR-155, miR-193b, and miR-221) following EAE development. Interestingly, serum levels of miR-99b, miR-125a, and miR-146b were significantly higher in EAE mice compared to normal mice. Bioinformatics analysis revealed the experimentally validated as well as predicted gene targets of specific miRNAs that are important for disease progression in MS. Specifically, we observed inverse correlation in the levels of miR-99b versus LIF, and between miR-125a versus BDNF and LIF. Our results suggest that above-mentioned miRNAs may play a crucial role in the pathogenesis of MS, and that miR-99b, miR-125a, and miR-146b in particular may serve as useful biomarkers for disease activity.

Progressive multifocal leukoencephalopathy after fingolimod treatment

OBJECTIVE

We describe the characteristics of the 15 patients with fingolimod-associated progressive multifocal leukoencephalopathy (PML) identified from the Novartis data safety base and provide risk estimates for the disorder.

METHODS

The Novartis safety database was searched for PML cases with a data lock point of August 31, 2017. PML classification was based on previously published criteria. The risk and incidence were estimated using the 15 patients with confirmed PML and the overall population of patients treated with fingolimod.

RESULTS

As of August 31, 2017, 15 fingolimod-treated patients had developed PML in the absence of natalizumab treatment in the preceding 6 months. Eleven (73%) were women and the mean age was 53 years (median: 53 years). Fourteen of the 15 patients were treated with fingolimod for >2 years. Two patients had confounding medical conditions. Two patients had natalizumab treatment. This included one patient whose last dose of natalizumab was 3 years and 9 months before the diagnosis of PML. The second patient was receiving fingolimod for 4 years and 6 months, which was discontinued to start natalizumab and was diagnosed with PML 3 months after starting natalizumab. Absolute lymphocyte counts were available for 14 of the 15 patients and none exhibited a sustained grade 4 lymphopenia (≤200 cells/μL).

CONCLUSIONS

The risk of PML with fingolimod in the absence of prior natalizumab treatment is low. The estimated risk was 0.069 per 1,000 patients (95% confidence interval: 0.039-0.114), and the estimated incidence rate was 3.12 per 100,000 patient-years (95% confidence interval: 1.75-5.15). Neither clinical manifestations nor radiographic features suggested any unique features of fingolimod-associated PML.

JC Virus-DNA Detection Is Associated with CD8 Effector Accumulation in Peripheral Blood of Patients with Multiple Sclerosis under Natalizumab Treatment, Independently from JC Virus Serostatus

Although natalizumab (anti-α4 integrin) represents an effective therapy for relapsing remitting multiple sclerosis (RRMS), it is associated with an increased risk of developing progressive multifocal leukoencephalopathy (PML), caused by the polyomavirus JC (JCV). The aim of this study was to explore natalizumab-induced phenotypic changes in peripheral blood T-lymphocytes and their relationship with JCV reactivation. Forty-four patients affected by RRMS were enrolled. Blood and urine samples were classified according to natalizumab infusion number: 0 (N0), 1–12 (N12), 13–24 (N24), 25–36 (N36), and over 36 (N > 36) infusions. JCV-DNA was detected in plasma and urine. T-lymphocyte phenotype was evaluated with flow cytometry. JCV serostatus was assessed. Ten healthy donors (HD), whose ages and sexes matched with the RRMS patients of the N0 group, were enrolled. CD8 effector (CD8 E) percentages were increased in natalizumab treated patients with detectable JCV-DNA in plasma or urine compared to JCV-DNA negative patients (JCV−) (p < 0.01 and p < 0.001, resp.). Patients with CD8 E percentages above 10.4% tended to show detectable JCV-DNA in plasma and/or urine (ROC curve p = 0.001). The CD8 E was increased when JCV-DNA was detectable in plasma or urine, independently from JCV serology, for N12 and N24 groups (p < 0.01). As long as PML can affect RRMS patients under natalizumab treatment with a negative JCV serology, the assessment of CD8 E could help in the evaluation of JCV reactivation.

Multiple sclerosis: genetics, biomarkers, treatments

PURPOSE OF REVIEW

We discuss new paradigms for understanding the immunopathology of multiple sclerosis through the recent development of high throughput genetic analysis, emergence of numerous candidate biomarkers, and the broadening of the treatment arsenal.

RECENT FINDINGS

The recent use of genome wide association studies provide new tools for a better understanding of multiple sclerosis etiology. Genome-wide association studies have identified many genes implicated in immune regulation and the next step will be to elucidate how those genetic variations influence immune cell function to drive disease development and progression. Furthermore, patient care has seen the emergence of new biomarkers for monitoring disease progression and response to treatment. Finally, the introduction of numerous immunomodulatory treatments will likely improve clinical outcome of multiple sclerosis patients in the future.

SUMMARY

Breakthroughs in the field of multiple sclerosis have led to a better understanding of the physiopathology of the disease, follow up, and treatment of the patients that develop relapsing remitting multiple sclerosis. The next challenge for multiple sclerosis will be to press forward to model and decipher multiple sclerosis progression, which will help both to develop therapeutics and generate knowledge about mechanisms of neurodegeneration.

Anti-JCV serology during natalizumab treatment: Review and meta-analysis of 17 independent patient cohorts analyzing anti-John Cunningham polyoma virus sero-conversion rates under natalizumab treatment and differences between technical and biological sero-converters

BACKGROUND

Anti-John Cunningham virus (JCV) serology has been studied with varying results concerning longitudinal changes.

OBJECTIVES AND METHODS

Results from 17 published natalizumab-treated multiple sclerosis (MS) patient cohorts were analyzed with common parameters and subsequently verified in two large independent cohorts with 722 and 499 patients from Germany and the United States.

RESULTS

Published studies and the verification showed (1) a mean of 10.80% sero-negative patients presented with sero-status change to positivity per year; (2) patients, who sero-convert to index values <0.9, convert from near the threshold and have a high probability of reverting with time; (3) patients, who convert to index values >0.9, start with low index values; (4) while JCV sero-positive patients with low index values sometimes revert to sero-negativity, patients with high index values almost never revert; and (5) the conversion rate of natalizumab-treated patients is three to four times higher than the biological conversion by age.

CONCLUSION

JCV sero-conversion was comparable using standardized parameters and indicates influence of natalizumab on JCV immune control. Converters to low index values are probably consistently infected with JCV with varying low levels of activity, in line with their low risk to develop progressive multifocal leukoencephalopathy (PML). Patients with high index values rarely revert back to sero-negativity.

Anti-JCV antibody serostatus and longitudinal evaluation in a Portuguese Multiple Sclerosis population

Multiple Sclerosis (MS) treatment with natalizumab is associated with Progressive Multifocal Leukoencephalopathy (PML). The risk of PML being related to the anti-JCV antibody index is well established, but there is less known about seroconversion rates in natalizumab-treated patients and longitudinal variation in the anti-JCV antibody index. Our objective was to assess anti-JCV antibody prevalence in an MS population and to evaluate the evolution of the anti-JCV antibody index in natalizumab-treated patients. To assess anti-JCV antibody prevalence, we included all patients who had the anti-JCV antibody test in our consultation, regardless of the treatment. To evaluate the evolution of the anti-JCV antibody index and seroconversion, only natalizumab-treated patients with at least two samples were selected. Demographic characteristics were evaluated. From a total of 371 patients included, 68.19% (n=253) were seropositive for anti-JCV antibodies (JCV+). There was a significant difference in anti-JCV antibody seropositivity concerning gender (male 76.27% vs. female 64.43%, p=0.023), but not age. To evaluate seroconversion, 85 patients who were initially seronegative (JCV-) were selected. The annual rate of seroconversion in the first two years was stable, but after that there was a significant increase with treatment duration (ρ=0.90, p=0.037): in the first year it was 5.88% (n=5/85); in the second, 5.71% (n=4/70); in the third, 6.82% (n=3/44); in the fourth, 10.34% (n=3/29); and in the fifth, 15.0% (n=3/20). The mean index variability was higher in patients who experienced seroconversion (1.16±0.97), followed by JCV+ patients (0.44±0.48), compared to JCV- patients (0.08±0.05). In conclusion, anti-JCV antibody prevalence in our population is comparable to other reported cohorts. The seroconversion rate increased with treatment duration. We found a high fluctuation in the antibody index in JCV+ patients.

John Cunningham virus conversion in relation to natalizumab concentration in multiple sclerosis patients

BACKGROUND AND PURPOSE

Infection with the John Cunningham virus (JCV) is required for the development of progressive multifocal leukoencephalopathy, the feared complication of natalizumab treatment in multiple sclerosis patients. The JCV seroconversion rate seems higher in natalizumab treated patients than in the normal population, with an unknown cause.

METHODS

Natalizumab concentration was correlated to JCV antibody status and seroconversion in a large cohort of multiple sclerosis patients.

RESULTS

One hundred and thirty-five patients were included. No correlation was found between natalizumab concentration and JCV status, JCV seroconversion or JCV index.

CONCLUSIONS

Higher natalizumab concentrations do not explain the increased JCV seroconversion rate in natalizumab treated patients.

JCV serology in time: 3 years of follow-up

OBJECTIVES

Although many neurologists are reluctant to use natalizumab in MS (multiple sclerosis) given the increased risk for PML (progressive multifocal leukoencephalopathy), trust was regained with the introduction of JCV antibody titres as a potent disease-modifying therapy. Literature shows that in patients with a negative JCV serology, the risk of PML is virtually non-existent. Unfortunately, seroconversion causes concern amongst many neurologists. Furthermore, when patients seroconvert, it is still unclear what the risk is of passing the important threshold of 1.5.

MATERIALS & METHODS

JCV serology data of 161 patients were analysed, upon treatment with natalizumab at the University Hospital in Lille, France, between May 2012 and November 2014.

RESULTS

Of the 81 patients who tested negative for JCV antibody at baseline, 23 (28.3%) seroconverted but only seven (8.6%) passed the threshold of 1.5. Of the 80 patients testing positive for JCV antibody at baseline, eight had an initial JCV antibody titre of 0.9 or lower of which only one of eight (12.5%) patients passed the threshold of 1.5 in the following 3 years. Eight of 15 (53.3%) patients passed this threshold if the initial serology was higher than 0.9.

CONCLUSIONS

JCV-negative patients and JCV-positive patients with antibody levels below or equal to 0.9 both have a low risk of surpassing the 1.5 threshold.

Is the risk of progressive multifocal leukoencephalopathy the real reason for natalizumab discontinuation in patients with multiple sclerosis?

Background

Progressive multifocal leukoencephalopathy (PML) is one of the major risks of natalizumab therapy. Despite introduction of the currently employed PML risk stratification algorithm, the incidence of natalizumab-associated PML cases is not decreasing.

Objectives

We addressed the following questions: How do natalizumab-treated multiple sclerosis patients and their treating physicians assess and deal with PML risk? Is PML risk the real reason for natalizumab discontinuation?

Methods

699 natalizumab-treated multiple sclerosis patients and 99 physicians were included in this prospective observational study. Questionnaires were completed at 5 different time points. Patients were stratified into 5 subgroups according to the presence of PML risk factors (prior immunosuppression, anti-JCV antibody status, treatment duration). Patients with prior immunosuppression (n = 30, treated by n = 7 physicians) were excluded from analyses, because patient numbers were too small. Patients’ anti-JCV antibody index was not considered because data recruitment ended in 2014. Using Bayesian network and regression analysis, we examined the relationship between different patient- and physician-related factors and patients’ discontinuation of natalizumab.

Results

Patients of all subgroups and physicians assessed the PML risk as low. Overall patient adherence to natalizumab was high (87%). Only 13% of patients discontinued therapy. Natalizumab treatment cessation was associated with different patient- and physician-related factors (physicians’ assessment of general PML risk, number of treated patients per year, natalizumab treatment duration, relapses during the course of study) upon which only physicians’ judgment on treatment continuation, patients’ perception of personal PML risk, and JCV seroconversion showed significant relationships.

Conclusion

According to the currently employed risk stratification algorithm, the objective PML risk probably doesn’t play a dominant role in a patients’ decision to continue or stop natalizumab treatment. The decision-making process is rather guided by subjective views and experiences of patients and treating neurologists. Treating physicians should consider this discrepancy in their advice to improve the risk-benefit-ratio for the individual patient.

Stability and predictive value of anti-JCV antibody index in multiple sclerosis: A 6-year longitudinal study

BACKGROUND

Risk of natalizumab-related progressive multifocal leukoencephalopathy is associated with the presence of anti-JC-virus (JCV) antibodies.

OBJECTIVE

To investigate the longitudinal evolution of anti-JCV antibody index and to determine the predictive value of baseline anti-JCV antibody index for long-term stability of anti-JCV antibody status.

METHODS

MS patients from the MS centre of Medical University of Innsbruck, who had serum sampling for a time period of 4-6 years at intervals of 6±3 months, were included in this retrospective, longitudinal study. Anti-JCV antibody serological status and index were determined by 2-step second-generation anti-JCV antibody assay.

RESULTS

154 patients were included in this study. Median follow-up time was 63.7 months, with median 11 samples available per patient. At baseline, 111 (72.1%) patients were anti-JCV antibody positive. Baseline anti-JCV antibody index significantly correlated with age (R = 0.22, p = 0.005); there was no difference with respect to sex, disease duration or previously used disease-modifying treatment. During follow-up anti-JCV antibody status changed from negative to positive or vice versa in 17% of patients. In seronegative patients at baseline, baseline anti-JCV antibody index was significantly lower in those remaining seronegative at follow-up compared to those converting to seropositivity (median 0.16 vs. 0.24, p = 0.002). In seropositive patients at baseline, index was higher in those remaining seropositive compared to those reverting to seronegativity (2.6 vs. 0.45, p<10-7). Baseline anti-JCV antibody index >0.90 predicted stable positive serostatus (sensitivity 88.7%, specificity 96.5%) and <0.20 stable negative serostatus (sensitivity 61.3%, specificity 97.6%).

CONCLUSIONS

Anti-JCV antibody index remained relatively stable over 6-year follow-up with annual serostatus change of ~3%. Baseline anti-JCV antibody index predicted stable negative and stable positive JCV serostatus.

Natalizumab-associated PML

Progressive multifocal leukoencephalopathy (PML) associated with natalizumab treatment continues to be a severe problem of clinically successful therapy. This is an update of risk stratification developments and discusses the current approach to depict and calculate PML incidence and PML risk. (1) PML incidence and resulting risk used in today's clinical practice are potentially outdated and the risk for patients with prior immunosuppression might have been underestimated. (2) Risk stratification according to treatment duration epochs likely suggests lower risk due to patients stopping treatment within a given epoch. PML incidence within the complete treatment epoch is statistically lowered due to the fact that patients at the beginning of an epoch presumably have a lower PML risk than the patients at the end. Periodic risk is not accurate in assessing risk for long treatment durations. (3) The JC virus (JCV) serostatus risk factor has low specificity concerning PML prediction and anti-JCV seroconversion during treatment with natalizumab further lowers its specificity over time. Specificity of the risk factor treatment duration varies depending on the average treatment duration and the number of short-term patients. These short-term patients reduce overall average treatment duration and thus enhance the specificity of the risk factor and reduce overall PML incidence. It is also suggested that short-term natalizumab patients are exclusively non-PML, even though they might still develop PML. Clinicians have to consider the cumulative risk of patients to stratify efficiently.

Study of the anti-JCV antibody levels in a Spanish multiple sclerosis cohort

BACKGROUND

One of the risk factor to develop progressive multifocal leukoencephalopathy (PML) among natalizumab-treated patients is the presence and high levels of anti-JCV antibodies. Our purpose was to test the association of different clinical and demographic variables with the presence and levels of anti-JCV antibodies in a Spanish cohort of patients with multiple sclerosis (MS) during natalizumab treatment.

MATERIALS AND METHODS

All patients with MS from two hospitals with at least one measure of the anti-JCV antibodies levels (2011-2014) were recruited, among them were two PML cases. Anti-JCV antibody levels were assessed using two-step ELISA.

RESULTS

A total of 1061 patients (16·3% natalizumab-treated) participated in this study. The seropositivity rate of anti-JCV antibodies was 58·2%. It increased with age (P_corrected = 0·00005) and was lower among HLA-DRB1*15:01 carriers (P_corrected = 0·049). The two patients with PML were HLA-DRB1*15:01 carriers. We had at least three quarterly anti-JCV antibody measurements (index value) from 137 patients, whose levels did not increase during natalizumab treatment. However, 5·8% of these patients had an increase of the index value higher of one point in a maximum of 6 months, something that was more frequently observed (P = 0·054) among patients treated with immunosuppressant prior to natalizumab onset.

CONCLUSIONS

Old age and HLA-DRB1*15:01 were the factors that influence positively and negatively, respectively, our anti-JCV antibody prevalence, although our both PML cases were HLA-DRB1*15:01carriers. Most of our patients showed a stable anti-JCV antibody index values during natalizumab treatment.

Anti-JC virus seroprevalence in a Finnish MS cohort

BACKGROUND

The risk of progressive multifocal leukoencephalopathy (PML) caused by the JC virus (JCV) is increased in patients with multiple sclerosis receiving biological therapies.

OBJECTIVES

To determine the seroprevalence of anti-JCV antibodies in Finnish patients with multiple sclerosis (MS) and clinically isolated syndrome and to assess the clinical risk factors for JCV seropositivity.

METHODS

The JCV seroprevalence was analyzed in 503 patients using a second-generation two-step ELISA. Sixty-seven patients underwent longitudinal serological evaluation over 4.5 years.

RESULTS

The overall seroprevalence of JCV was 57.4%. The seropositivity was higher in men than in women, tended to increase with age, and was not affected by different immunomodulatory therapies. However, in patients with ongoing natalizumab treatment (n = 72), the anti-JCV antibody screening index was lower than in patients without such therapy [median 0.3 (range 0.1-3.1) vs 0.6 (0.1-3.1), respectively, P = 0.01]. Over 4.5 years, 4/19 (21%) initially seronegative patients converted to seropositivity, whereas 4/48 (8.3%) initially seropositive patients reverted to seronegativity. Fluctuations in serostatus were observed in 3/67 patients.

CONCLUSION

The study confirmed a high anti-JCV antibody prevalence in patients with MS and its association with age and male gender but not with disease-modifying therapies. Our data suggest that therapy with natalizumab may cause a decrease in anti-JCV antibody levels, suggesting an immunosuppressive effect of natalizumab without an impact on JCV seroprevalence. The results of studies performed until now confirm the predictive value of anti-JCV antibody measurement in the assessment of PML risk; however, changes in serostatus need to be considered.

Anti-JC virus seroprevalence in a Spanish multiple sclerosis cohort: JC virus seroprevalence in Spain

OBJECTIVE

To estimate the seroprevalence of anti-JCV antibodies, seroconverting rates and evolution of antibody levels in a multiple sclerosis (MS) Spanish cohort.

METHODS

Multicenter, retrospective cross-sectional and longitudinal study. The JCV seroprevalence was analyzed in 711 MS patients by using 1st (STRATIFY-1) and 2nd generation (STRATIFY-2) two-step ELISA over 2.65 (±0.97) years. Seroconversion rate was obtained over 2 samples from 314 patients, and index stability from 301 patients with 3 or more samples available. The effect of each ELISA generation, demographics, clinical characteristics and therapy on seroprevalence was assessed by logistic regression.

RESULTS

The overall anti-JCV seroprevalence was 55.3% (51.6-58.9), similar across regions (p=0.073). It increased with age (p<0.000) and when STRATIFY-2 was used (60.5%, p=0.001). Neither sex nor immunosuppressive therapy had any influence. Yearly seroconversion rate was 7% (considering only STRATIFY-2). Serological changes were observed in 24/301 patients, 5.7% initially seropositive reverted to seronegative and 7% initially seronegative changed to seropositive and again to seronegative, all these cases had initial index values around the assay's cut-off.

CONCLUSIONS

JCV seroprevalence in Spanish MS patients was similar to that reported in other European populations. Changes in serostatus are not infrequent and should be considered in clinical decisions.

Re-evaluating the incidence of natalizumab-associated progressive multifocal leukoencephalopathy

OBJECTIVE

To estimate the prospective risk of developing PML during therapy with natalizumab in JCV-seropositive patients.

METHODS

We analyzed postmarketing data about the incidence of PML on natalizumab, and quantified the risk by either applying the Kaplan-Meier estimator or, where this was not possible due to the unavailability of the respective raw data, using formulae yielding very similar figures.

RESULTS

In JCV-seropositive patients with prior immunosuppressant (IS) use, the incidence of PML during months 25-48 of natalizumab therapy is about 19.5 per thousand. Without prior IS use, the incidence during months 25-48 is approximately 7.4 per thousand, and during months 49-72, it is approximately 10.8 per thousand. If one additionally assumes that the JCV index is in the range 0.9-1.5, then the incidence during months 49-72 is around 6.2 per thousand in comparison to 17.0 per thousand when the JCV index exceeds 1.5.

CONCLUSIONS

Biogen's statistics concerning the risk of PML on natalizumab, while in principle helpful, underestimate the true incidence systematically and significantly; realistic estimates of the longterm risk of PML are nearly double those previously published, with some patient groups carrying a risk that is almost nine times higher. Fortunately, a refined risk-stratification algorithm with the incorporation of such markers as L-selectin and CSF lipid-specific IgM bands has the potential to make natalizumab a considerably safer drug.

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.

Stratification and monitoring of natalizumab-associated progressive multifocal leukoencephalopathy risk: recommendations from an expert group

The use of natalizumab for highly active relapsing-remitting multiple sclerosis (MS) is influenced by the occurrence of progressive multifocal leukoencephalopathy (PML). Through measurement of the anti-JCV antibody index, and in combination with the presence or absence of other known risk factors, it may be possible to stratify patients with MS according to their risk of developing PML during treatment with natalizumab and detect early suspected PML using MRI including a diffusion-weighted imaging sequence. This paper describes a practical consensus guideline for treating neurologists, based on current evidence, for the introduction into routine clinical practice of anti-JCV antibody index testing of immunosuppressant-naïve patients with MS, either currently being treated with, or initiating, natalizumab, based on their anti-JCV antibody status. Recommendations for the frequency and type of MRI screening in patients with varying index-associated PML risks are also discussed. This consensus paper presents a simple and pragmatic algorithm to support the introduction of anti-JCV antibody index testing and MRI monitoring into standard PML safety protocols, in order to allow some JCV positive patients who wish to begin or continue natalizumab treatment to be managed with a more individualised analysis of their PML risk.

Anti-JC virus antibody titres increase over time with natalizumab treatment

Background:

Anti-JC virus antibody status is a risk factor for progressive multifocal leukoencephalopathy after natalizumab treatment in multiple sclerosis. Previous studies have used a cross-sectional approach to conclude that the presence and duration of natalizumab treatment does not influence anti-JCV Ab seropositivity.

Objectives:

Using a longitudinal approach, we measured change in anti-JCV Ab results after natalizumab treatment.

Methods:

Anti-JCV Ab results ( n = 1154) from the second-generation STRATIFY JCV™ DxSelect™ test were analysed from an observational cohort of MS patients on natalizumab ( n = 485; n = 340 with repeat testing; n = 657 repeat tests on natalizumab).

Results:

Across sequential paired tests, seroconversion rate was greater than seroreversion rate (40/364 (11.0%) versus 18/293 (6.1%); p < 0.05). Moreover, anti-JCV Ab index increased across longitudinal paired tests ( mA–B 0.102; paired t(656) = 5.0; p < 0.0001). This magnitude of Ab level increase far exceeds that expected due to increasing age alone.

Conclusion:

Our data suggest that natalizumab therapy is associated with a significant and substantial increase in anti-JCV Ab index over time. Further work should focus on the underlying mechanisms of this phenomenon, and the clinical relevance to risk stratification.

Longitudinal JCV serology in multiple sclerosis patients preceding natalizumab-associated progressive multifocal leukoencephalopathy

The presence of anti-John Cunningham Virus (JCV) antibodies is a risk factor for the development of progressive multifocal leukoencephalopathy (PML) in MS patients treated with natalizumab. It has been suggested that an increase in serum anti-JCV antibody index precedes the development of PML. We here describe extensive longitudinal serum anti-JCV antibody indexes of four MS patients who developed PML. Anti-JCV antibodies were measured using the STRATIFY JCV™DxSelect™ test. All four patients had rather stable high anti-JCV antibody indexes in all samples obtained before developing PML. Possibly caused by reaching the saturation level of the assay, no increase in anti-JCV antibody indexes was seen just before the diagnosis of PML. This study confirms that high serum anti-JCV antibody indexes precede natalizumab-associated PML.

Anti-JC virus antibodies in rituximab-treated patients with neuromyelitis optica spectrum disorder

Rituximab, a chimeric monoclonal anti-CD20 antibody, has been proposed to be effective for neuromyelitis optica spectrum disorder (NMOSD). A concern for developing progressive multifocal leukoencephalopathy (PML), which is caused by John Cunningham virus (JCV), has been suggested particularly in patients treated long term with rituximab. In this study, using a modified enzyme-linked immunosorbent assay with glutathione S-transferase-tagged VP1 as the antigen, we investigated the seroprevalence of anti-JCV antibodies among 78 Korean patients with NMOSD and the change in anti-JCV antibody serostatus following long-term rituximab treatment. The overall seroprevalence of anti-JCV antibodies was 69 % prior to rituximab administration. Over a mean of 4 years of repeated treatment with rituximab, no patient developed PML. Of 24 initially seronegative patients, none converted into seropositive, whereas six (11 %) of 54 initially seropositive patients converted into seronegative. Our results might support the safety of long-term rituximab treatment in patients with NMOSD with regard to the risk of developing PML.