Anti-John Cunnigham virus antibody prevalence in multiple sclerosis patients: baseline results of STRATIFY-1

Frequent detection of IFN-gamma -producing memory effector and effector T cells in patients with progressive multifocal leukoencephalopathy

Introduction

Progressive Multifocal Leukoencephalopathy (PML) is a rare and deadly demyelinating disease caused by JC virus (JCV) replication in the central nervous system. PML occurs exclusively in patients with severe underlying immune deficiencies, including AIDS and hematological malignancies. PML has also emerged as a significant threat to patients on potent new immunosuppressive biologics, including natalizumab in multiple sclerosis.

Methods

Here, we developed an IFN-γ release assay (IGRA) that mainly detects JCV-specific effector memory T cells and effectors T cells in the blood.

Results

This assay was frequently positive in patients with active PML (with a positive JCV PCR in CSF) of various underlying immunosuppression causes (84% sensitivity). Only 3% of healthy donors had a positive response (97% specificity). The frequency of positivity also increased in multiple sclerosis patients according to the time on natalizumab (up to 36% in patients treated for more than 48 months, who are considered at a higher risk of PML).

Discussion

The results show this assay's frequent or increased positivity in patients with PML or an increased risk of PML, respectively. The assay may help to stratify the risk of PML.

Generation of JC Polyoma Pseudovirus for High-Throughput Measurement of Neutralizing Antibodies

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system (CNS) caused by reactivation of dormant JC polyomavirus (JCPyV). PML was mainly observed in immunocompromised individuals, such as HIV-positive patients, autoimmune disease patients, and cancer patients. Given that the presence of anti-JCPyV antibodies in serum is a risk indicator for PML development, it is essential to monitor anti-JCPyV antibody levels. In the present study, we established reporter-based single-infection neutralization assays for JCPyV and the genetically similar BK polyoma virus (BKPyV). We then confirmed the lack of cross-reactivity between the two viruses using test sera obtained from mice immunized with plasmids encoding the JCPyV or BKPyV capsid. Next, we compared neutralization antibody titers in sera from healthy donors, patients with multiple sclerosis (MS), and HIV-positive patients using an in-house enzyme-linked immunosorbent assay (ELISA) with JCPyV-like particles (virus-like particles; VLPs). A positive correlation was demonstrated between the neutralization titer (75% infectious concentration; IC75) against JCPyV and the antibody titer obtained by VLP-based JCPyV ELISA. This assay system may be applied to detect antibodies against other PyVs by generation of pseudoviruses using the respective capsid expression plasmids, and is expected to contribute to the surveillance of PyV as well as basic research on these viruses.

Switching from natalizumab administration at the day hospital to administration at home. A 1 year prospective study of patient experience and quality of life in 30 consecutive patients with multiple sclerosis (TYSAD-35)

BACKGROUND

In the context of the COVID-19 pandemic, French health authorities allowed the home administration of natalizumab by a healthcare-at-home service. We evaluated the patients' perception of care quality following the transition from day-hospital to home natalizumab administration.

METHODS

Thirty relapsing-remitting multiple sclerosis (MS) patients treated with natalizumab were prospectively evaluated for one year after changing onto a home treatment procedure, using MusiCare, the first MS-specific questionnaire to evaluate patient experience and MusiQol. A numerical rating scale score for satisfaction and a dedicated questionnaire concerning patient experience were completed after each infusion. The primary endpoint was the mean difference in MusiCare score between baseline and 12 months.

RESULTS

From June 2020 to November 2021, 306 infusions were performed at home. Three patients withdrew from the study (one lost to follow-up and two preferred to return at the day hospital). No worsening of patient experience or quality of life was observed. The mean scores of the Musicare dimensions were higher at 12 months than at baseline, significantly for the "relationship with healthcare professionals" (p = 0.0203). The MusiQol global score remained stable but the coping and friendship dimensions were significantly better at M12 than at baseline (p = 0.0491 and p = 0.0478, respectively). The satisfaction questionnaire highlighted some pain during the infusions (21.8%) and contradictions between healthcare professionals (17.2%). The mean score for satisfaction with care was 9.1/10. No safety concerns were identified.

CONCLUSION

The positive experience of patients with home natalizumab administration provides an important opportunity to improve the quality of patient care.

Disorders of vision in multiple sclerosis

Multiple sclerosis (MS) is a neurological inflammatory disorder known to attack the heavily myelinated regions of the nervous system including the optic nerves, cerebellum, brainstem and spinal cord. This review will discuss the clinical manifestations and investigations for MS and other similar neurological inflammatory disorders affecting vision, as well as the effects of MS treatments on vision. Assessment of visual pathways is critical, considering MS can involve multiple components of the visual pathway, including optic nerves, uvea, retina and occipital cortex. Optical coherence tomography is increasingly being recognised as a highly sensitive tool in detecting subclinical optic nerve changes. Magnetic resonance imaging (MRI) is critical in MS diagnosis and in predicting long-term disability. Optic neuritis in MS involves unilateral vision loss, with characteristic pain on eye movement. The visual loss in neuromyelitis optica spectrum disorder tends to be more severe with preferential altitudinal field loss, chiasmal and tract lesions are also more common. Other differential diagnoses include chronic relapsing inflammatory optic neuropathy and giant cell arteritis. Leber's hereditary optic neuropathy affects young males and visual loss tends to be painless and subacute, typically involving both optic nerves. MS lesions in the vestibulocerebellum, brainstem, thalamus and basal ganglia may lead to abnormalities of gaze, saccades, pursuit and nystagmus which can be identified on eye examination. Medial longitudinal fasciculus lesions can cause another frequent presentation of MS, internuclear ophthalmoplegia, with failure of ipsilateral eye adduction and contralateral eye abduction nystagmus. Treatments for MS include high-dose corticosteroids for acute relapses and disease-modifying medications for relapse prevention. These therapies may also have adverse effects on vision, including central serous retinopathy with corticosteroid therapy and macular oedema with fingolimod.

PML risk is the main factor driving the choice of discontinuing natalizumab in a large multiple sclerosis population: results from an Italian multicenter retrospective study

BACKGROUND

Natalizumab (NTZ) is an effective treatment for relapsing-remitting multiple sclerosis (RRMS). However, patients and physicians may consider discontinuing NTZ therapy due to safety or efficacy issues. The aim of our study was to evaluate the NTZ discontinuation rate and reasons of discontinuation in a large Italian population of RRMS patients.

MATERIALS AND METHODS

The data were extracted from the Italian MS registry in May 2018 and were collected from 51,845 patients in 69 Italian multiple sclerosis centers. MS patients with at least one NTZ infusion in the period between June 1st 2012 to May 15th 2018 were included. Discontinuation rates at each time point were calculated. Reasons for NTZ discontinuation were classified as "lack of efficacy", "progressive multifocal leukoencephalopathy (PML) risk" or "other".

RESULTS

Out of 51,845, 5151 patients, 3019 (58.6%) females, with a mean age of 43.6 ± 10.1 years (median 40), were analyzed. Out of 2037 (39.5%) who discontinued NTZ, a significantly higher percentage suspended NTZ because of PML risk compared to lack of efficacy [1682 (32.7% of 5151) vs 221 (4.3%), p < 0.001]; other reasons were identified for 99 (1.9%) patients. Patients discontinuing treatment were older, had longer disease duration and worse EDSS at the time of NTZ initiation and at last follow-up on NTZ treatment. The JCV index and EDSS at baseline were predictors for stopping therapy (HR 2.94, 95% CI 1.22-4.75; p = 0.02; HR 1.36, 95% CI 1.18-5.41; p = 0.04).

CONCLUSIONS

Roughly 60% of MS patients stayed on NTZ treatment during the observation period. For those patients in whom NTZ discontinuation was required, it was mainly due to PML concerns.

JC Virus Seroprevalence and JCVAb Index in Polish Multiple Sclerosis Patients Treated with Immunomodulating or Immunosuppressive Therapies

The use of a highly-effective treatment for multiple sclerosis (MS) is associated with a severe risk of developing complications, such as progressive multifocal leukoencephalopathy (PML) caused by the John Cunningham virus (JCV). The aim of this study was to evaluate the correlation between anti-JCV Ab seroprevalence, anti-JCV AI, demographic and clinical factors as well as the type of therapy used in the Polish MS population. This is a multicentre, prospective and cross-sectional study involving 1405 MS patients. The seroprevalence of anti-JCV Ab and anti-JCV AI levels as well as AI categories were analysed with the use of a second-generation two-step ELISA test (STRATIFY JCV DxSelect). The overall prevalence of anti-JCV Ab was 65.8%. It was shown that seroprevalence increases with the patient's age. The seroprevalence was significantly associated with the treatment type, and the highest values (76%) were obtained from immunosuppressant-treated patients. Overall, 63.3% of seropositive patients had an antibody index (AI) level of >1.5. In the seropositive patient group, the mean AI level amounted to 2.09. Similarly to the seroprevalence, AI levels correlated with the patient's age; AI level for patients above 40 years old and from subsequent age quintiles plateaued, amounting to at least 1.55. Patients treated with immunosuppressants and immunomodulatory drugs obtained the highest (1.67) and lowest (1.35) AI levels, respectively. Of the immunosuppressants used, the highest mean AI levels were observed in mitoxantrone and cladribine groups, amounting to 1.75 and 1.69, respectively. In patients treated with immunomodulatory drugs, the lowest AI levels were observed in the dimethyl fumarate (DMF) group (1.11). The seroprevalence rate in the Polish MS population is one of the highest in Europe. The majority of seropositive patients had an anti-JCV Ab level qualifying them for a high-risk category. The highest mean AI levels are observed in patients receiving immunosuppressants, especially mitoxantrone and cladribine. Patients receiving immunomodulatory drugs have lower AI levels compared to treatment-naïve subjects, especially when treated with DMF. Further studies, especially longitudinal studies, are required to determine the impact of MS drugs on the seroprevalence of anti-JCV Ab and AI levels.

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.

JC Virus Seroprevalence and JCVAb Index in Polish Multiple Sclerosis Treatment-Naïve Patients

Multiple sclerosis (MS) treatment with new agents is associated with the risk of the development of progressive multifocal leukoencephalopathy (PML). The seropositivity and a high index of anti-John Cunningham virus (JCV) antibodies are some of the risk factors for PML development. The aim of this study was to assess the seroprevalence of anti-JCVAb and JCVAb index (AI), as well as its correlations with demographic and clinical characteristics in treatment-naïve Polish MS patients. This is a multicenter, prospective, and cross-sectional study involving 665 MS patients. The overall prevalence of anti-JCVAb was 65.3%, while 63.1% of seropositive patients had an index level of >1.5. The seroprevalence was shown to increase along with the patient's age. Except for age, the prevalence of anti-JCVAb was not associated with demographic or clinical data. No correlations between the index levels and the demographic or clinical data were observed. In Poland, the seroprevalence of anti-JCVAb in treatment-naïve MS patients is one of the highest in Europe. The majority of seropositive patients had an anti-JCV antibody level denoting a high-risk category. This means that we need further studies to be conducted on the individualization of MS treatment in order to provide patients with an appropriate therapeutic safety level.

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.

Prevalence of Anti-JC Virus Antibody Seropositivity in Patients with Multiple Sclerosis: A Systematic Review and Meta-Analysis

BACKGROUND

The John Cunningham virus (JCV) is the causative agent of progressive multifocal leukoencephalopathy. Anti-JCV antibody seropositivity is an important consideration in patients with multiple sclerosis (MS). The reported prevalence of JCV in MS patients has been conflicting.

OBJECTIVE

We aimed to conduct a systematic review and meta-analysis to estimate the pooled prevalence of anti-JCV antibody seropositivity in cases with MS.

METHODS

We searched PubMed, Scopus, EMBASE, CINAHL, Web of Science, Ovid, ProQuest, Google Scholar, and gray literature including reference of included studies, and conference abstracts which were published up to April 2019. Two independent researchers independently assessed the articles.

RESULTS

The literature search found 181 articles. After eliminating duplicates, reviews, case reports, and trials, 15 articles remained. Finally, 8 articles were included for the final analysis (from Asia, Europe, the USA, and Canada). In total, 16,041 MS cases were analyzed. The prevalence of anti-JCV antibody seropositivity varied between 40 and 80%, and the pooled estimate was calculated as 60% (95% CI: 56-64%), though with significant heterogeneity (I2 = 95%, p = 0.01).

CONCLUSION

The prevalence of anti-JCV antibody seropositivity is variable among MS patients in different countries, and the pooled estimate showed that this is 60% overall.

Treatment of Progressive Multifocal Leukoencephalopathy Using Immune Restoration

Progressive multifocal leukoencephalopathy (PML) is a viral disease of the brain associated with immunodeficiency, immune suppressing medications, and malignancy. In the absence of effective anti-viral therapy for the causative JC virus, immune restoration has emerged as the critical therapeutic alternative. The evolving treatment of PML (and other rare JC virus-associated neurologic syndromes) requires consideration of baseline immune functioning and comorbid diseases while selecting from a number of therapeutic options to restore an effective immune response. This review focuses on the current options for management of PML in typical situations where this disease presents, including several where immune restoration is a standard therapeutic approach such as in PML associated with HIV/AIDS and in multiple sclerosis associated with natalizumab. Other circumstances in which PML occurs including associated with primary immunodeficiencies, malignancies, and transplants present greater challenges to immune reconstitution, but emerging concepts may enhance therapeutic options for these situations. Particular attention is focused on recent experience with checkpoint inhibitors, guidance for MS drug discontinuation, and strategies to monitor and facilitate immune restoration.

Direct T-cell Inhibition and Agents Targeting T-cell Migration and Chemotaxis

Lymphocyte depletion and blockade of T-cell activation and trafficking serve as therapeutic strategies for an enlarging number of immune-mediated diseases and malignancies. This review summarizes the infection risks associated to monoclonal antibodies that bind to the α chain of the interleukin-2 receptor, the cell surface glycoprotein CD52, and members of α4- and β2-integrin families acting as cell-adhesion molecules. An outline of the mechanisms of action, approved indications and off-label uses, expected impact on the host immune response, and available clinical evidence is provided for each of these agents.

Dynamic expression of JC virus in urine and its relationship to serostatus

BACKGROUND

There is limited information regarding the daily shedding of JC virus (JCV) in urine and its correlation with serum JCV antibody levels.

METHODS

The dynamic expression of JCV in urine and its correlation with JCV antibody status in patients receiving disease modifying therapy for multiple sclerosis were examined in a longitudinal case-control study. JCV antibody index levels were determined using a two-step ELISA (Stratify). JCV shedding in urine samples was determined by quantitative PCR during two 30-day study periods separated by intervals of at least 6 months.

RESULTS

Of 42 study subjects (57% female; ages 22-56, average age 39.6 years), 27 (64.3%) were JCV antibody positive (index >0.40) at initial urine collection. Twelve seropositive subjects (44.4%) had detectable JCV in their urine with values ranging from 290 to 5.08 × 10⁸ copies/mL. Daily viral shedding in these patients remained fairly constant throughout the study. Urinary JCV shedding was not detected in any JCV antibody index negative or indeterminate subject. In JCV urinary shedders, the average JCV antibody index was 2.69 (range 1.67-3.57). The average anti-JCV antibody index for the remaining JCV seropositive individuals without viral urinary shedding was 1.35 (range 0.46-3.91).

CONCLUSION

MS patients displayed a consistent pattern of JCV shedding over days and months in which higher levels of viruria appeared to have driven higher levels of JCV antibody index. The findings provide additional insights into the dynamic expression of JCV and host response; however, studies in larger populations and of longer duration will be needed to determine their significance to the development of progressive multifocal leukoencephalopathy (PML).

JC virus antibodies in Portuguese multiple sclerosis patients: JUSTIFY study results

OBJECTIVE

To confirm anti-JC virus (JCV) antibody seroprevalence in Portuguese patients with relapsing-remitting multiple sclerosis (RRMS) and to determine their anti-JCV antibody index.

METHODS

JUSTIFY was a retrospective, multicentre study that included 655 RRMS patients tested at least once with the anti-JCV antibody assay STRATIFY JCV DxSelect. Demographic data, multiple sclerosis history and results of the anti-JCV antibody test were collected, along with physicians' reasons for requesting the test and the impact of the results.

RESULTS

Overall anti-JCV antibody seroprevalence was 60.8% (95% confidence interval, 56.9-64.5). Seroprevalence was associated with higher age (P = .030) and was lower in natalizumab-treated patients (P < .001). The mean anti-JCV antibody index of immunosuppressant-naive patients was 1.5 ± 1.3 (n = 378). The main reasons for performing the test were clinical characterization (35.5%) and medication change (26.2%). In patients who switched treatments (n = 109), fingolimod (47.7%) and natalizumab (26.6%) were the most commonly chosen new treatments.

CONCLUSIONS

The study confirmed the high anti-JCV antibody prevalence in Portuguese RRMS patients and its association with age. These data can be used to better understand the benefit-risk profile of natalizumab treatment in Portuguese patients and to support progressive multifocal leukoencephalopathy risk management strategies.

Post-natalizumab disease reactivation in multiple sclerosis: systematic review and meta-analysis

Background

Natalizumab (NTZ) is sometimes discontinued in patients with multiple sclerosis, mainly due to concerns about the risk of progressive multifocal leukoencephalopathy. However, NTZ interruption may result in recrudescence of disease activity.

Objective

The objective of this study was to summarize the available evidence about NTZ discontinuation and to identify which patients will experience post-NTZ disease reactivation through meta-analysis of existing literature data.

Methods

PubMed was searched for articles reporting the effects of NTZ withdrawal in adult patients (⩾18 years) with relapsing-remitting multiple sclerosis (RRMS). Definition of disease activity following NTZ discontinuation, proportion of patients who experienced post-NTZ disease reactivation, and timing to NTZ discontinuation to disease reactivation were systematically reviewed. A generic inverse variance with random effect was used to calculate the weighted effect of patients' clinical characteristics on the risk of post-NTZ disease reactivation, defined as the occurrence of at least one relapse.

Results

The original search identified 205 publications. Thirty-five articles were included in the systematic review. We found a high level of heterogeneity across studies in terms of sample size (10 to 1866 patients), baseline patient characteristics, follow up (1-24 months), outcome measures (clinical and/or radiological), and definition of post-NTZ disease reactivation or rebound. Clinical relapses were observed in 9-80% of patients and peaked at 4-7 months, whereas radiological disease activity was observed in 7-87% of patients starting at 6 weeks following NTZ discontinuation. The meta-analysis of six articles, yielding a total of 1183 patients, revealed that younger age, higher number of relapses and gadolinium-enhanced lesions before treatment start, and fewer NTZ infusions were associated with increased risk for post-NTZ disease reactivation (p ⩽ 0.05).

Conclusions

Results from the present review and meta-analysis can help to profile patients who are at greater risk of post-NTZ disease reactivation. However, potential reporting bias and variability in selected studies should be taken into account when interpreting our data.

Post-natalizumab disease reactivation in multiple sclerosis: systematic review and meta-analysis

Background:

Natalizumab (NTZ) is sometimes discontinued in patients with multiple sclerosis, mainly due to concerns about the risk of progressive multifocal leukoencephalopathy. However, NTZ interruption may result in recrudescence of disease activity.

Objective:

The objective of this study was to summarize the available evidence about NTZ discontinuation and to identify which patients will experience post-NTZ disease reactivation through meta-analysis of existing literature data.

Methods:

PubMed was searched for articles reporting the effects of NTZ withdrawal in adult patients (⩾18 years) with relapsing–remitting multiple sclerosis (RRMS). Definition of disease activity following NTZ discontinuation, proportion of patients who experienced post-NTZ disease reactivation, and timing to NTZ discontinuation to disease reactivation were systematically reviewed. A generic inverse variance with random effect was used to calculate the weighted effect of patients’ clinical characteristics on the risk of post-NTZ disease reactivation, defined as the occurrence of at least one relapse.

Results:

The original search identified 205 publications. Thirty-five articles were included in the systematic review. We found a high level of heterogeneity across studies in terms of sample size (10 to 1866 patients), baseline patient characteristics, follow up (1–24 months), outcome measures (clinical and/or radiological), and definition of post-NTZ disease reactivation or rebound. Clinical relapses were observed in 9–80% of patients and peaked at 4–7 months, whereas radiological disease activity was observed in 7–87% of patients starting at 6 weeks following NTZ discontinuation. The meta-analysis of six articles, yielding a total of 1183 patients, revealed that younger age, higher number of relapses and gadolinium-enhanced lesions before treatment start, and fewer NTZ infusions were associated with increased risk for post-NTZ disease reactivation (p ⩽ 0.05).

Conclusions:

Results from the present review and meta-analysis can help to profile patients who are at greater risk of post-NTZ disease reactivation. However, potential reporting bias and variability in selected studies should be taken into account when interpreting our data.

Impact of Disease-Modifying Treatments on the Longitudinal Evolution of Anti-JCV Antibody Index in Multiple Sclerosis

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

Objective: To investigate the impact of disease-modifying treatments (DMT) on the longitudinal evolution of anti-JCV antibody index.

Methods: Patients with multiple sclerosis who had serum sampling at intervals of 6 ± 3 months over up to 6 years and who either started DMT (interferon-β, glatiramer acetate or natalizumab) during the observation period with at least one serum sample available before and after treatment initiation or received no DMT during the observation period were included. Anti-JCV antibody serological status and index were determined by 2-step second-generation anti-JCV antibody assay.

Results: A total of 89 patients were followed for a median time of 55.2 months. Of those, 62 (69.7%) started DMT and 27 (30.3%) were without therapy during the observation period. Variation of longitudinal anti-JCV antibody index ranged from 9 to 15% and was similar in patients with and without DMT. Applying a mixed model considering the combined effects of treatment and time as well as individual heterogeneity did not show a significant change of anti-JCV antibody index by the start of treatment with interferon-β, glatiramer acetate, or natalizumab.

Conclusion: Evaluated DMTs do not impact longitudinal anti-JCV antibody index evolution.

Identification of Peptide Mimotope Ligands for Natalizumab

Mimotope peptides selected from combinatorial peptide libraries can be used as capture reagents for immunoassay detection of therapeutic monoclonal antibodies (mAbs). We report the use of phage display libraries to identify peptide ligands (Veritopes^TM) that bind natalizumab, a therapeutic mAb indicated for use in multiple sclerosis. PKNPSKF is identified as a novel natalizumab-binding motif, and peptides containing this motif demonstrated utility as capture reagents in enzyme-linked immunosorbent assays (ELISAs). A peptide containing the identified motif was shown to be competitive with the natural ligand (α4-integrin) and a neutralizing anti-idiotype antibody for natalizumab binding, indicating that Veritopes^TM act as surrogate ligands that bind the antigen binding site of natalizumab. Affinity maturation further confirmed the motif sequence and yielded peptides with greater apparent affinity by ELISA. Veritopes^TM are promising assay reagents for therapeutic drug level monitoring.

Anti-JC virus antibody sera positivity and index value among patients with multiple sclerosis may be correlated with age, sex, and area of residence

Anti-JC virus (JCV) antibody index is the predictive factor of progressive multifocal leukoencephalopathy (PML) for multiple sclerosis (MS) patients treating with natalizumab. The aim of this study is to evaluate the prevalence of anti-JCV antibody positivity and index among Iranian patients who are the candidate for natalizumab and its correlation with their demographic data and previous therapies. A cross-sectional design was assessed for receiving anti-JCV antibody test results between January 2014 and December 2016. Demographic data and disease characteristics were also obtained. Statistical analysis and logistic regression were done using SPSS. Among 803 MS patients that were observed, the prevalence of anti-JCV antibody positivity was 67.9% (mean of index = 2.23 ± 1.16) and 67.6% of positive patients had an index ≥ 1.5. Males were more antibody positive than females (81.7 and 64% respectively; significance (sig.) < 0.001, OR = 2.51, CI 1.65-3.81). The rate of positivity was lower in patients under the age of 18. Patients who lived in cold regions had significantly more prevalence of positivity (Num. = 403; sig. = 0.043 and OR = 1.86; CI 1.02-3.39) and with higher rate of index ≥ 1.5 (sig. = 0.017; OR = 3.99, CI 1.79-8.88). Disease onset age between 28 and 37 years were more positive compared to 18-27 years (N = 480; sig. = 0.02; OR = 1.85, CI 1.09-3.14). Age, male gender, onset age, and cold area of residency significantly influenced anti-JCV antibody sera positivity. Only age of onset and cold area of residency were related to the index. No significant difference was observed between type, dosage, and duration of previous immunosuppressant drugs and anti-JCV antibody positivity and index value.

Serum anti-JCV antibody indexes in Japanese patients with multiple sclerosis: elevations along with fingolimod treatment duration

BACKGROUND

The risk of developing progressive multifocal leukoencephalopathy in natalizumab-treated multiple sclerosis (MS) patients is related to serum anti-JCV antibody (JCVAb) index. However, the correlation of JCVAb index with other disease-modifying treatments (DMTs) is not well understood.

OBJECTIVE

In this study, we investigated the JCVAb seropositivity rate/JCVAb indexes and its correlation with clinical profiles in Japanese MS patients, and the relationship between JCVAb indexes and DMTs.

METHODS

JCVAb indexes were measured in 149 serum samples from 105 patients with MS. JCVAb indexes and seropositivity, and their correlation with age, sex, disease duration, Kurtzke expanded disability status scale and the duration of the DMTs were evaluated in each patient.

RESULTS

JCVAb was positive in 73 of 105 MS patients. Within 40 fingolimod-treated patients, 27 were positive for JCVAb and JCVAb indexes were positively correlated with the duration of fingolimod treatment. No significant relation was found between JCVAb indexes and the duration of treatment for the other disease-modifying drugs.

CONCLUSION

JCVAb seropositivity was comparatively high in Japanese MS patients. Fingolimod treatment is likely to increase serum JCVAb index, possibly leading to the development of PML. Therefore, it is advised that JCVAb index should be serially monitored during fingolimod treatment to decrease PML risk.

Systematic review of the published data on the worldwide prevalence of John Cunningham virus in patients with multiple sclerosis and neuromyelitis optica

OBJECTIVES

John Cunningham virus (JCV) is a polyoma virus that infects humans, mainly in childhood or adolescence, and presents no symptomatic manifestations. JCV can cause progressive multifocal leukoencephalopathy (PML) in immunosuppressed individuals, including those undergoing treatment for multiple sclerosis (MS) and neuromyelitis optica (NMO). PML is a severe and potentially fatal disease of the brain. The prevalence of JCV antibodies in human serum has been reported to be between 50.0 and 90.0%. The aim of the present study was to review worldwide data on populations of patients with MS and NMO in order to establish the rates of JCV seropositivity in these individuals.

METHODS

The present review followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines and used the following search terms: “JCV” OR “JC virus” AND “multiple sclerosis” OR “MS” OR “NMO” OR “neuromyelitis optica” AND “prevalence.” These terms were searched for both in smaller and in larger clusters of words. The databases searched included PubMed, MEDLINE, SciELO, LILACS, Google Scholar, and Embase.

RESULTS

After the initial selection, 18 papers were included in the review. These articles reported the prevalence of JCV antibodies in the serum of patients with MS or NMO living in 26 countries. The systematic review identified data on 29,319 patients with MS/NMO and found that 57.1% of them (16,730 individuals) were seropositive for the anti-JCV antibody (range, 40.0 to 69.0%).

CONCLUSIONS

The median worldwide prevalence of JCV among adults with MS or NMO was found to be 57.1%.

Safety and Effectiveness of Natalizumab: First Report of Interim Results of Post-Marketing Surveillance in Japan

INTRODUCTION

Natalizumab, a humanized anti-α4 integrin monoclonal antibody, received marketing approval in Japan in 2014 for the treatment of multiple sclerosis (MS). Because the previous large-scale clinical trials of natalizumab were mainly conducted in Europe and North American countries, and data in patients with MS from Japan were limited, we conducted an all-case post-marketing surveillance of natalizumab-treated MS patients from Japan to investigate the safety and effectiveness of natalizumab in a real-world clinical setting in Japan. Here, we report the results of an interim analysis.

METHODS

During the observation period of 2 years, all patients who were treated with natalizumab subsequent to its approval in Japan were followed. The effectiveness of natalizumab was assessed by examining the changes in expanded disability status scale (EDSS) score and annualized relapse rate (ARR) from baseline. Safety was assessed by analyzing the incidence of adverse drug reactions (ADRs).

RESULTS

The safety analysis included 106 patients (mean age 39.3 years; women 62.3%) whose data were collected until the data lock point (February 7, 2016). The effectiveness analysis included 75 patients. The majority of patients had relapsing-remitting MS (93/106 patients; 87.7%). The mean length of treatment exposure in the present study was 6.6 months. During the 2-year observation period, no significant change in the EDSS was observed, while the ARR decreased significantly from baseline (72.9% reduction, p = 0.001). ADRs and serious ADRs were observed in 11.3% and 3.8% of patients, respectively; however, no new safety concerns were detected. No patient had progressive multifocal leukoencephalopathy (PML) during the present study period.

CONCLUSION

The safety and effectiveness of natalizumab were confirmed in Japanese patients with MS in clinical practice. Nevertheless, potential risks including PML require continuous, careful observation.

FUNDING

Biogen Japan Ltd (Tokyo, Japan).

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.

Age as a risk factor for early onset of natalizumab-related progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is a rare but potentially fatal opportunistic infection that arises almost exclusively in immunocompromised patients or in those treated with monoclonal antibodies, especially natalizumab. Here, we aimed at exploring if age at treatment start affects the time to onset of natalizumab-related PML. PubMed was searched for the terms "natalizumab and progressive multifocal leukoencephalopathy" in articles published from January 2005 to March 2017. We collected information on each identified PML case, including demographic and clinical variables at natalizumab start and at PML onset. The number of natalizumab infusions until PML onset was investigated in time-to-event analyses. We identified 238 cases who developed PML after a median number of 33 natalizumab infusions (range 6 to 103). Risk factors for an earlier onset of natalizumab-related PML were prior immunosuppressant exposure (hazard ratio [HR] = 1.43, p = 0.017) and older age at treatment start (HR = 1.02, p = 0.016). In particular, patients older than 50 years had a more than doubled-increased risk for an earlier PML onset (HR = 2.11, p = 0.006). Our findings suggest that the age at natalizumab start may represent a risk factor for an earlier PML onset, thus claiming further investigations about the interplay between immunosenescence and MS treatments.

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.

Neurotherapeutic Strategies for Multiple Sclerosis

Multiple sclerosis (MS) is the most common disabling neurologic disease of young adults. There are now 16 US Food and Drug Administration (FDA)-approved disease-modifying therapies for MS as well as a cohort of other agents commonly used in practice when conventional therapies prove inadequate. This article discusses approved FDA therapies as well as commonly used practice-based therapies for MS, as well as those therapies that can be used in patients attempting to become pregnant, or in patients with an established pregnancy, who require concomitant treatment secondary to recalcitrant disease activity.

Novel Insights into the Mechanisms of Gut Homing and Antiadhesion Therapies in Inflammatory Bowel Diseases

Therapeutic compounds interfering with T cell trafficking are a new column of inflammatory bowel disease (IBD) treatment. Currently, the anti-α4β7 integrin antibody vedolizumab is successfully used in the clinic and further drugs are likely to follow. Despite these clinical advances, the precise mechanistic background of their action is only gradually elucidated and still a matter of intensive research. Only recently, advances made with the help of new in vivo models and human studies have contributed to shape our concept of T cell trafficking in IBD by deciphering some important and so far unanswered questions. At the same time, basic and clinical data have generated new issues to be addressed on the way toward a clear perception of trafficking mechanisms and toward elucidation of the action of compounds interfering with this process. In this review, we will give a comprehensive outline of all components of T cell trafficking in regard to IBD before discussing the current knowledge concerning targeted interference with integrins in this complex network. Moreover, we will summarize remaining ambiguity and give an outlook on potential future targets.

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.

The use of natalizumab for multiple sclerosis

Natalizumab is a monoclonal antibody that acts as an α4 integrin antagonist to prevent leukocyte trafficking into the central nervous system. It is US Food and Drug Administration (FDA) approved for the treatment of relapsing-remitting multiple sclerosis (RRMS). Natalizumab demonstrated high efficacy in Phase III trials by reducing the annualized relapse rate, preventing multiple sclerosis (MS) lesion accumulation on magnetic resonance imaging, and decreasing the probability of sustained progression of disability. The leading safety concern with natalizumab is its association with progressive multifocal leukoencephalopathy (PML), a rare brain infection typically seen only in severely immunocompromised patients caused by reactivation of the John Cunningham virus (JCV). Careful analysis of risk factors for PML in natalizumab-treated MS patients, specifi-cally the presence of anti-JCV antibodies, has led to risk mitigation strategies to improve safety. Additional biomarkers are under investigation to further aid risk stratification. Natalizumab's high efficacy and favorable tolerability profile have led to a broad use by MS physicians, as both first-and second-line treatments. This review discusses the natalizumab efficacy, safety, and tolerability and finishes with pragmatic considerations regarding its use in clinical practice.

Efficacy, safety, and pharmacokinetics of natalizumab in Japanese multiple sclerosis patients: A double-blind, randomized controlled trial and open-label pharmacokinetic study

BACKGROUND

Natalizumab, an anti-α4 integrin monoclonal antibody, has demonstrated efficacy in phase 2 and 3 studies of predominantly Caucasian patients with relapsing-remitting multiple sclerosis (RRMS).

OBJECTIVE

To evaluate the efficacy, safety, pharmacokinetics (PK), and pharmacodynamics (PD) of natalizumab in Japanese RRMS patients.

METHODS

This multicenter, phase 2 study included an open-label PK/PD study in 12 patients (part A) and a double-blind, placebo-controlled, randomized (computer-generated sequence) study in 94 patients (part B). For part B, patients received intravenous natalizumab 300mg (n=47) or placebo (n=47) every 4 weeks. The primary efficacy endpoint was the rate of development of new active lesions (gadolinium-enhancing or new/enlarging T2 lesions) over 24 weeks. Clinical relapses and safety were also assessed.

RESULTS

New active lesions developed at a significantly lower mean rate in natalizumab-treated patients (0.06 lesions/24 weeks) than in placebo-treated patients (0.35 lesions/24 weeks) (p<0.001). The annualized relapse rate was 0.53 for natalizumab and 1.73 for placebo (p<0.001). Twice as many natalizumab-treated patients (79%) as placebo-treated patients (38%) were relapse-free (p<0.001). The safety, PK, and PD profiles of natalizumab in this study were consistent with data in Caucasian RRMS patients.

CONCLUSIONS

In Japanese RRMS patients, natalizumab treatment every 4 weeks for 24 weeks was well tolerated and reduced the development of new brain lesions and relapses (Funded by Biogen; ClinicalTrials.gov identifier: NCT01440101).

Polyomavirus detection in multiple sclerosis patients under natalizumab therapy: Profile and frequency of urinary shedding

Patients undergoing Natalizumab (NTZ) therapy are at risk of progressive multifocal leukoencephalopathy (PML). Besides John Cunningham virus (JCV), BK polyomavirus might represent an additional concern for such patients since it can also infect CNS cells. Currently, data regarding the presence of anti-JCV antibodies added to previous immunosuppressive therapy and prolonged NTZ therapy has been used to classify patients at risk of developing PML. Here, we investigated the profile shedding of JCV and BKV in multiple sclerosis (MS) patients during treatment with NTZ. Serial blood and urine samples from 97 MS patients receiving either NTZ or β-interferon were investigated for polyomavirus shedding. While all blood samples tested negative, 36% of the patients shed polyomavirus in the urine in at least one time point. From these, 21.7%, 9.3%, and 5.1% shed JCV, BKV, and both polyomavirus, respectively. No difference was observed between the rates of urinary shedding of patients treated with NTZ (38.9%) and patients treated with other drugs (34.5%), also no PML event was diagnosed during the follow-up. Therefore, urinary shedding might not be interfered by therapy condition. In our study, we also observed 14/27 (52%) of anti-JCV antibodies prevalence, and nearly half of them (42%) did not present any event of urinary shedding during the follow-up. J. Med. Virol. 89:528-534, 2017. © 2016 Wiley Periodicals, Inc.

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

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

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.

Monoclonal antibody therapies for the treatment of relapsing-remitting multiple sclerosis: differentiating mechanisms and clinical outcomes

Monoclonal antibody (mAb) therapies for relapsing-remitting multiple sclerosis (MS) target immune cells or other molecules involved in pathogenic pathways with extraordinary specificity. Natalizumab and alemtuzumab are the only two currently approved mAbs for the treatment of MS, having demonstrated significant reduction in clinical and magnetic resonance imaging disease activity and disability in clinical studies. Ocrelizumab and daclizumab are in the late stages of phase III trials, and several other mAbs are in the early stages of clinical evaluation. mAbs have distinct structural characteristics (e.g. chimeric, humanized, fully human) and unique targets (e.g. blocking interactions, induction of signal transduction by receptor binding, complement-dependent cytotoxicity, antibody-dependent cell-mediated cytotoxicity) conferring different mechanisms of action in MS. Because of these differences, mAbs for MS do not constitute a single treatment class; each must be considered individually when selecting appropriate therapy. Furthermore, in reviewing the data from clinical studies of mAbs, attention should be drawn to use of different comparators (e.g. placebo or interferon β-1a) and study designs. Each mAb treatment has a unique administration schedule. In the decision to select the appropriate treatment for each individual MS patient, careful review of the benefits relative to risks of mAbs is balanced against the risk of development of MS-associated disability.

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.

JC polyomavirus mutants escape antibody-mediated neutralization

JC polyomavirus (JCV) persistently infects the urinary tract of most adults. Under conditions of immune impairment, JCV causes an opportunistic brain disease, progressive multifocal leukoencephalopathy (PML). JCV strains found in the cerebrospinal fluid of PML patients contain distinctive mutations in surface loops of the major capsid protein, VP1. We hypothesized that VP1 mutations might allow the virus to evade antibody-mediated neutralization. Consistent with this hypothesis, neutralization serology revealed that plasma samples from PML patients neutralized wild-type JCV strains but failed to neutralize patient-cognate PML-mutant JCV strains. This contrasted with serological results for healthy individuals, most of whom robustly cross-neutralized all tested JCV variants. Mice administered a JCV virus-like particle (VLP) vaccine initially showed neutralizing "blind spots" (akin to those observed in PML patients) that closed after booster immunization. A PML patient administered an experimental JCV VLP vaccine likewise showed markedly increased neutralizing titer against her cognate PML-mutant JCV. The results indicate that deficient humoral immunity is a common aspect of PML pathogenesis and that vaccination may overcome this humoral deficiency. Thus, vaccination with JCV VLPs might prevent the development of PML.

Broadly neutralizing human monoclonal JC polyomavirus VP1-specific antibodies as candidate therapeutics for progressive multifocal leukoencephalopathy

In immunocompromised individuals, JC polyomavirus (JCPyV) may mutate and gain access to the central nervous system resulting in progressive multifocal leukoencephalopathy (PML), an often fatal opportunistic infection for which no treatments are currently available. Despite recent progress, the contribution of JCPyV-specific humoral immunity to controlling asymptomatic infection throughout life and to eliminating JCPyV from the brain is poorly understood. We examined antibody responses against JCPyV major capsid protein VP1 (viral protein 1) variants in the serum and cerebrospinal fluid (CSF) of healthy donors (HDs), JCPyV-positive multiple sclerosis patients treated with the anti-VLA-4 monoclonal antibody natalizumab (NAT), and patients with NAT-associated PML. Before and during PML, CSF antibody responses against JCPyV VP1 variants show "recognition holes"; however, upon immune reconstitution, CSF antibody titers rise, then recognize PML-associated JCPyV VP1 variants, and may be involved in elimination of the virus. We therefore reasoned that the memory B cell repertoire of individuals who recovered from PML could be a source for the molecular cloning of broadly neutralizing antibodies for passive immunization. We generated a series of memory B cell-derived JCPyV VP1-specific human monoclonal antibodies from HDs and a patient with NAT-associated PML-immune reconstitution inflammatory syndrome (IRIS). These antibodies exhibited diverse binding affinity, cross-reactivity with the closely related BK polyomavirus, recognition of PML-causing VP1 variants, and JCPyV neutralization. Almost all antibodies with exquisite specificity for JCPyV, neutralizing activity, recognition of all tested JCPyV PML variants, and high affinity were derived from one patient who had recovered from PML. These antibodies are promising drug candidates for the development of a treatment of PML.