Anti-JC virus (JCV) antibody prevalence in the JCV Epidemiology in MS (JEMS) trial

Chemokine-mediated cell migration into the central nervous system in progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) has been associated with different forms of immune compromise. This study analyzes the chemokine signals and attracted immune cells in cerebrospinal fluid (CSF) during PML to define immune cell subpopulations relevant for the PML immune response. In addition to chemokines that indicate a general state of inflammation, like CCL5 and CXCL10, the CSF of PML patients specifically contains CCL2 and CCL4. Single-cell transcriptomics of CSF cells suggests an enrichment of distinct CD4+ and CD8+ T cells expressing chemokine receptors CCR2, CCR5, and CXCR3, in addition to ITGA4 and the genetic PML risk genes STXBP2 and LY9. This suggests that specific immune cell subpopulations migrate into the central nervous system to mitigate PML, and their absence might coincide with PML development. Monitoring them might hold clues for PML risk, and boosting their recruitment or function before therapeutic immune reconstitution might improve its risk-benefit ratio.

John Cunningham Virus and Progressive Multifocal Leukoencephalopathy: A Falsely Played Diagnosis

Progressive Multifocal Leukoencephalopathy (PML) is a possibly fatal demyelinating disease and John Cunningham Polyomavirus (JCPyV) is believed to cause this condition. The so-called JCPyV was initially reported in lymphoma and Human Immunodeficiency Virus (HIV) cases, whereas nowadays, its incidence is increasing in Multiple Sclerosis (MS) cases treated with natalizumab (Tysabri). However, there are conflicting literature data on its pathology and diagnosis, whereas some misdiagnosed reports exist, giving rise to further questions towards the topic. In reality, the so-called PML and the supposed JCPyV are not what they seem to be. In addition, novel and more frequent PML-like conditions may be reported, especially after the Coronavirus Disease 2019 (COVID-19) pandemic.

Drug-Induced Progressive Multifocal Leukoencephalopathy (PML): A Systematic Review and Meta-Analysis

INTRODUCTION

Progressive multifocal leukoencephalopathy (PML) was first described among patients affected by hematological or solid tumors. Following the human immunodeficiency virus (HIV) epidemic, people living with HIV have represented most cases for more than a decade. With the diffusion of highly active antiretroviral therapy, this group progressively decreased in favor of patients undergoing treatment with targeted therapy/immunomodulators. In this systematic review and meta-analysis, the objective was to assess which drugs are most frequently related to PML development, and report the incidence of drug-induced PML through a meta-analytic approach.

METHODS

The electronic databases MEDLINE, EMBASE, ClinicalTrials.gov, Web of Science and the Canadian Agency for Drugs and Technologies in Health Database (CADTH) were searched up to May 10, 2022. Articles that reported the risk of PML development after treatment with immunomodulatory drugs, including patients of both sexes under the age of 80 years, affected by any pathology except HIV, primary immunodeficiencies or malignancies, were included in the review. The incidence of drug-induced PML was calculated based on PML cases and total number of patients observed per 100 persons and the observation time. Random-effect metanalyses were conducted for each drug reporting pooled incidence with 95% confidence intervals (CI) and median (interquartile range [IQR]) of the observation time. Heterogeneity was measured by I2 statistics. Publication bias was examined through funnel plots and Egger's test.

RESULTS

A total of 103 studies were included in the systematic review. In our analysis, we found no includible study reporting cases of PML during the course of treatment with ocrelizumab, vedolizumab, abrilumab, ontamalimab, teriflunomide, daclizumab, inebilizumab, basiliximab, tacrolimus, belimumab, infliximab, firategrast, disulone, azathioprine or danazole. Dalfampridine, glatiramer acetate, dimethyl fumarate and fingolimod show a relatively safe profile, although some cases of PML have been reported. The meta-analysis showed an incidence of PML cases among patients undergoing rituximab treatment for multiple sclerosis (MS) of 0.01 cases/100 persons (95% CI - 0.08 to 0.09; I2 = 20.4%; p = 0.25) for a median observation period of 23.5 months (IQR 22.1-42.1). Treatment of MS with natalizumab carried a PML risk of 0.33 cases/100 persons (95% CI 0.29-0.37; I2 = 50%; p = 0.003) for a median observation period of 44.1 months (IQR 28.4-60) and a mean number of doses of 36.3 (standard deviation [SD] ± 20.7). When comparing data about patients treated with standard interval dosing (SID) and extended interval dosing (EID), the latter appears to carry a smaller risk of PML, that is, 0.08 cases/100 persons (95% CI 0.0-0.15) for EID versus 0.3 cases/100 persons (95% CI 0.25-0.34) for SID.

CONCLUSIONS

A higher risk of drug-related PML in patients whose immune system is not additionally depressed by means of neoplasms, HIV or concomitant medications is found in the neurological field. This risk is higher in MS treatment, and specifically during long-term natalizumab therapy. While this drug is still routinely prescribed in this field, considering the efficacy in reducing MS relapses, in other areas it could play a smaller role, and be gradually replaced by other safer and more recently approved agents.

Prevalence of JC Polyomavirus in Patients with Neuroinvasive Disease of Unknown Etiology in Croatia

Background and Objectives: John Cunningham polyomavirus (JCPyV) is a highly prevalent virus in the human population. The prevalence of JCPyV in patients with central nervous system disorders has not been examined extensively. The aim of this study was to analyze the prevalence of JCPyV DNA/antibodies in patients with neuroinvasive diseases (NID) of unknown etiology. Materials and Methods: The study included 132 patients with NID (febrile headache, meningitis, encephalitis) tested from January 2021 to December 2022. The control group consisted of 47 asymptomatic individuals. In patients with NID, serum and cerebrospinal fluid (CSF) samples were collected in the acute phase of the disease. CSF samples were tested for JCPyV DNA (PCR), while serum samples were tested for JCPyV IgG antibodies (ELISA). In controls, serum samples were tested for JCPyV IgG antibodies (ELISA). Results: JCPyV DNA was not detected in any of the CSF samples from patients with NID. JCPyV IgG antibodies were detected in 88.6% of patients and 74.5% of controls (p < 0.001). In the patients' group, a significant difference in the IgG prevalence was observed between males (94.6%) and females (81.0%). In addition, significant differences in the seropositivity between age groups were found. The lowest seroprevalence (28.6%) was in patients less than 20 years, followed by a sharp increase in the 20-29-year group (69.2%), after which the seroprevalence remained stable (90.0-94.1%) in patients up to 69 years. All patients older than 70 years were JCPyV IgG-seropositive. No significant difference in the seroprevalence was found in patients presenting with febrile headache (81.6%), meningitis (93.3%), or meningoencephalitis (91.3%). No difference in the seropositivity between genders was found in controls. Although the seropositivity steadily increased in older participants, these differences were not significant. Analyzing the JCPyV antibody levels in patients with NID, the median antibody titers differed significantly between groups, ranging from 248 AU/mL (younger age groups) to 400 AU/mL (older age groups). Conclusions: Higher seroprevalence in the patients' group highlights the need to further investigate the possible association of JCPyV and NID.

Progressive Multifocal Leukoencephalopathy: Pathogenesis, Diagnostic Tools, and Potential Biomarkers of Response to Therapy

JC polyomavirus (JCV) establishes an asymptomatic latent and/or persistent infection in most of the adult population. However, in immunocompromised individuals, JCV can cause a symptomatic infection of the brain, foremost progressive multifocal leukoencephalopathy (PML). In the past 2 decades, there has been increasing concern among patients and the medical community because PML was observed as an adverse event in individuals treated with modern (selective) immune suppressive treatments for various immune-mediated diseases, especially multiple sclerosis. It became evident that this devastating complication also needs to be considered beyond the patient populations historically at risk, including those with hematologic malignancies or HIV-infected individuals. We review the clinical presentation of PML, its variants, pathogenesis, and current diagnostic approaches. We further discuss the need to validate JCV-directed interventions and highlight current management strategies based on early diagnosis and restoring JCV-specific cellular immunity, which is crucial for viral clearance and survival. Finally, we discuss the importance of biomarkers for diagnosis and response to therapy, instrumental in defining sensitive study end points for successful clinical trials of curative or preventive therapeutics. Advances in understanding PML pathophysiology, host and viral genetics, and diagnostics in conjunction with novel immunotherapeutic approaches indicate that the time is right to design and perform definitive trials to develop preventive options and curative therapy for JCV-associated diseases.

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.

JCV seroconversion rate during the SARS COVID-19 pandemic

The transmission route of the John Cunningham virus (JCV) is not clearly understood. The high prevalence of JCV in urine and sewage and the stability of the viral particles observed suggest that contaminated water, food, and fomites could be the vehicles of JCV transmission through the oral route. Multiple Sclerosis (MS) patients treated with Natalizumab are at risk of developing progressive multifocal leukoencephalopathy (PML), and hence, JCV serology is monitored for risk stratification. Social restrictions introduced in 2020 which intended to limit the transmission of SARS-CoV-2 are associated with decreased rates of other communicable diseases, as has been shown in recent observational studies. We evaluated the prevalence of seroconversion prior to and during the coronavirus disease (COVID -19) pandemic based on clinical records of JCV serology status in a single-center cohort of Natalizumab-treated Multiple Sclerosis patients. We hypothesized that seroconversion rates would decrease due to behavioral changes. However, seroconversion rates were stable during the COVID-19 pandemic compared to the pre-pandemic. These findings support the notion that JCV is transmitted via the GI tract rather than the respiratory system.

Identification of host-pathogen-disease relationships using a scalable multiplex serology platform in UK Biobank

Certain infectious agents are recognised causes of cancer and other chronic diseases. To understand the pathological mechanisms underlying such relationships, here we design a Multiplex Serology platform to measure quantitative antibody responses against 45 antigens from 20 infectious agents including human herpes, hepatitis, polyoma, papilloma, and retroviruses, as well as Chlamydia trachomatis, Helicobacter pylori and Toxoplasma gondii, then assayed a random subset of 9695 UK Biobank participants. We find seroprevalence estimates consistent with those expected from prior literature and confirm multiple associations of antibody responses with sociodemographic characteristics (e.g., lifetime sexual partners with C. trachomatis), HLA genetic variants (rs6927022 with Epstein-Barr virus (EBV) EBNA1 antibodies) and disease outcomes (human papillomavirus-16 seropositivity with cervical intraepithelial neoplasia, and EBV responses with multiple sclerosis). Our accessible dataset is one of the largest incorporating diverse infectious agents in a prospective UK cohort offering opportunities to improve our understanding of host-pathogen-disease relationships with significant clinical and public health implications.

Molecular biomarkers in multiple sclerosis

Multiple sclerosis (MS) is a highly heterogenous disease regarding radiological, pathological, and clinical characteristics and therapeutic response, including both the efficacy and safety profile of treatments. Accordingly, there is a high demand for biomarkers that sensitively and specifically apprehend the distinctive aspects of the MS heterogeneity, and that can aid in better understanding of the disease diagnosis, prognosis, prediction of the treatment response, and, finally, in the development of new treatments. Currently, clinical characteristics (e.g., relapse rate and disease progression) and magnetic resonance imaging play the most important role in the clinical classification of MS and assessment of its course. Molecular biomarkers (e.g., immunoglobulin G (IgG) oligoclonal bands, IgG index, anti-aquaporin-4 antibodies, neutralizing antibodies against interferon-beta and natalizumab, anti-varicella zoster virus and anti-John Cunningham (JC) virus antibodies) complement these markers excellently. This review provides an overview of exploratory, validated and clinically useful molecular biomarkers in MS which are used for prediction, diagnosis, disease activity and treatment response.

[Pharmacoeconomic aspects of using cladribine (in tablets) for treatment of adult patients with remitting multiple sclerosis]

OBJECTIVE

To conduct a pharmacoeconomic analysis of using cladribine (in tablets) as a second-line treatment option for adult patients with highly active remitting multiple sclerosis in Russia.

MATERIAL AND METHODS

Current treatment practice of highly active multiple sclerosis (natalizumab, fingolimod, alemtuzumab, ocrelizumab) was considered as a comparator for cladribine (in tablets). Clinical and economic study was conducted using the «cost minimization» method. For budget impact analysis cost of using cladribine (in tablets) was compared to the cost of using current treatment practice.

RESULTS

Cladribine in tablets is a cost-saving alternative for treatment of patients with highly active multiple sclerosis compared to the current treatment practice. Within a 4-year period direct medical costs reduction is 2 million RUB (50.1%) per person.

CONCLUSION

In case of switching the patients, who are currently provided with other disease modifying drugs, to cladribine, in 4 years health budget will save up to 6284 million RUB (50.1%).

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.

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.

Assessing and mitigating risk of infection in patients with multiple sclerosis on disease modifying treatment

Introduction: The important development that the multiple sclerosis (MS) treatment field has experienced in the last years comes along with the need of dealing with new adverse events such as the increase risk of infections. In the shared therapeutic decision-making process, the MS expert neurologist should also balance the risks of specific infections under each particular treatment and be familiar with new mitigation strategies.Areas covered: In this review, the authors provide an up-to-date review of the infection risk associated with MS treatments with a specific focus on risk mitigating strategies. The search was conducted using Pubmed® database (2000 - present) to identify publications that reported infection rates and infection complications for each treatment (interferon beta, glatiramer acetate, teriflunomide, dimethyl fumarate, fingolimod, cladribine, natalizumab, alemtuzumab, rituximab, and ocrelizumab).Expert opinion: Since the emergence of the first natalizumab-related PML case, the arrival of new MS therapies has come hand in hand with new infectious complications. MS-specialist neurologist has to face new challenges regarding the management of immunosuppression-related infectious complications. The implementation of patient-centered management focus on preventive and mitigating strategies with a multidisciplinary approach should be seen in the future as a marker of excellence of MS management.

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.

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.

Infectious Complications of Biological and Small Molecule Targeted Immunomodulatory Therapies

The past 2 decades have seen a revolution in our approach to therapeutic immunosuppression. We have moved from relying on broadly active traditional medications, such as prednisolone or methotrexate, toward more specific agents that often target a single receptor, cytokine, or cell type, using monoclonal antibodies, fusion proteins, or targeted small molecules. This change has transformed the treatment of many conditions, including rheumatoid arthritis, cancers, asthma, and inflammatory bowel disease, but along with the benefits have come risks. Contrary to the hope that these more specific agents would have minimal and predictable infectious sequelae, infectious complications have emerged as a major stumbling block for many of these agents. Furthermore, the growing number and complexity of available biologic agents makes it difficult for clinicians to maintain current knowledge, and most review articles focus on a particular target disease or class of agent. In this article, we review the current state of knowledge about infectious complications of biologic and small molecule immunomodulatory agents, aiming to create a single resource relevant to a broad range of clinicians and researchers. For each of 19 classes of agent, we discuss the mechanism of action, the risk and types of infectious complications, and recommendations for prevention of infection.

Germline Genetic Risk Variants for Progressive Multifocal Leukoencephalopathy

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

Rapid cognitive decline in a patient with chronic lymphocytic leukaemia: a case report

Background

The use of monoclonal antibodies in various settings has been linked to the development of progressive multifocal leukoencephalopathy (PML). Whilst this association is well-described with agents such as rituximab and natalizumab, the literature describing the occurrence of PML with ofatumumab therapy (especially in a haematology setting) is sparse. This case aims to draw attention to the above association with a particular focus on the mechanisms by which B-cell-depleting therapy can precipitate PML during the treatment of haematological malignancy.

Case presentation

A 68-year-old Caucasian man presented with acute-on-subacute confusion and reduced mobility. He had a history of chronic lymphocytic leukaemia for which he had completed six cycles of ofatumumab and chlorambucil 2 months prior to presentation. Biochemistry, physical examination and imaging were unremarkable on admission. Subsequent neurological examination demonstrated diminished reflexes and an extensor right plantar, while magnetic resonance imaging (MRI) assessment revealed white matter hyperintensities in the frontal lobes with restricted diffusion surrounding these areas. Cerebrospinal fluid (CSF) analysis demonstrated normal cell counts and chemistry but detected John Cunningham virus (JCV) via polymerase chain reaction (PCR), with a quantitative value of 41,850 gEg/ml. CSF immunophenotyping excluded malignant processes. A diagnosis of PML was confirmed, and with the support of palliative care, the patient was discharged to a hospice for ongoing care with the family’s agreement.

Conclusion

PML remains a rare complication of ofatumumab treatment. Nevertheless, clinicians should maintain a certain level of suspicion for this risk, especially in the context of patients presenting with clinical syndromes of encephalopathy and focal neurologic deficits. Furthermore, research to better our understanding of the manifold links between B-cell function and JCV regulation could provide valuable information for use in the future prevention and treatment of PML.

Could JC virus be linked to chronic idiopathic intestinal pseudo-obstruction?

JC virus is a member of the Polyomavirus family, infects humans worldwide, and 90% of the population carry antibodies to the virus by adult life. The initial infection is asymptomatic, but it may become persistent. JC virus DNA is frequently present in the upper and lower gastrointestinal tracts of healthy adults. Chronic idiopathic intestinal pseudo-obstruction, one of the most severe gastrointestinal motility disorders, is a condition characterized by a clinical picture mimicking small bowel occlusion with related symptoms and signs in the absence of demonstrable mechanical obstruction. Because of the known neuropathic capability of this virus, and its frequent presence in the gut, it has been proposed that JCV might be detectable in tissues of patients with chronic idiopathic intestinal pseudo-obstruction, and possibly be involved in the pathogenesis of this disease, because the virus may actively infect the enteroglial cells of the myenteric plexuses of the patients with chronic idiopathic intestinal pseudo-obstruction. We report two cases of upper idiopathic intestinal pseudo-obstruction associated with JCV infection.

Risk of Progressive Multifocal Leukoencephalopathy in the Combination Antiretroviral Therapy Era in the French Hospital Database on Human Immunodeficiency Virus (ANRS-C4)

Background

Risk factors for progressive multifocal leukoencephalopathy (PML) in individuals with human immunodeficiency virus (HIV) infection are poorly documented in the era of combination antiretroviral therapy (cART).

Methods

We studied HIV-1-infected individuals aged ≥15 years who had no history of PML and were prospectively followed up between 1997 and 2011 in the French Hospital Database on HIV (FHDH-ANRS CO4) cohort. Cox models were used to calculate adjusted hazard ratios (HRs), focusing on sub-Saharan origin, suggested to be protective, and recent cART initiation, potentially associated with an increased risk of PML.

Results

PML developed in 555 individuals, in 57 during the first 6 months of cART. From 1997-2000 to 2009-2011, the incidence fell from 1.15 (95% confidence interval [CI], .98-1.31) to 0.49 (.37-.61) per 1000 person-years. Sub-Saharan African origin had no clear influence (HR, 0.80; 95% CI, .58-1.11). Compared with men who have sex with men, injection drug users (IDUs) were at higher risk (HR, 1.80 [95% CI, 1.32-2.45] for male and 1.68 [1.13-2.48] for female IDUs). When IDUs were excluded, hepatitis C virus seropositivity was associated with an increased risk (HR, 1.40; 95% CI, 1.02-1.93). Compared with no cART initiation, initiation <6 months previously was associated with PML onset (HR, 4.91; 95% CI, 2.42-9.95).

Conclusions

Recent cART initiation is associated with an increased risk of PML, as are injection drug use and hepatitis C virus seropositivity. Sub-Saharan African origin had no protective effect.

Prevalence of Anti-JC Virus (JCV) Antibodies in the Multiple Sclerosis (MS) Population in Cyprus: A Retrospective Study

Background and Purpose

Progressive multifocal leukoencephalopathy (PML) is a debilitating disease of the central nervous system caused by the ubiquitous polyomavirus JC (JCV) in immunocompromised hosts. In recent years, a new subpopulation of patients at risk for PML has emerged, due to the growing use of immunomodulatory or immunosuppressive therapies in autoimmune diseases such as multiple sclerosis (MS). The anti-JCV antibody index is used as a stratification tool in assessing the risk of developing PML. The objective of this study was to retrospectively describe the prevalence of anti-JCV antibodies in the MS population in Cyprus.

Methods

We retrospectively collected the demographics of 214 MS patients in Cyprus who were screened for anti-JCV antibodies using the STRATIFY JCV™ assay between September 2011 and June 2018. Logistic regression analysis was used to examine the effect of demographic variables on seropositivity, and bivariate tests were used to assess the association between demographic characteristics and JCV AI index.

Results

A total of 214 MS patients in Cyprus were tested. Overall anti-JCV antibody prevalence was 45.8% (95% confidence interval 37.2%–55.8%). We could not establish a significant association between seropositivity and increasing age or sex. In the subgroup analysis of natalizumab-treated patients, the annual seroconversion rate was 4.5%.

Conclusions

Overall seroprevalence of anti-JCV antibodies in MS patients in Cyprus using the STRATIFY JCV assay was lower than the worldwide reported mean. Although previously reported, in our study, the anti-JCV antibody seropositivity was not associated with increasing age or sex.

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.

Conversion and reversion of anti-John Cunningham virus antibody serostatus: A prospective study

INTRODUCTION

Determination of antibodies against the John Cunningham virus (JCV) is an important tool for risk stratification in Natalizumab-treated multiple sclerosis (MS) patients. Six-monthly testing has been suggested for anti-JCV antibody negative patients and patients with low antibody index in order to detect changes of serostatus. We conducted a prospective study with predefined testing intervals in order to investigate the predictability of anti-JCV antibody status and the intervals for repetitive testing.

METHODS

Our study included 109 patients at the MS Clinic of the Departments of Neurology, Medical Universities of Innsbruck and Salzburg. Blood withdrawals were performed at five time points: baseline, month 1, 3, 6, and 12. Patients' sera were sent to Unilabs, Copenhagen, Denmark, where anti-JCV antibodies were tested by a two-step enzyme-linked immunosorbent assay. Qualitative (negative/positive) and quantitative results (anti-JCV antibody index) were used for statistical analyses.

RESULTS

In our cohort, 52.3% of the patients were positive for anti-JCV antibodies at baseline, with a significant correlation with age, but no association with sex or prior disease-modifying therapy. Seven patients converted and reverted from negative to positive status and vice versa around the cut-off index of 0.4, but no patient showed a permanent seroconversion from negative to highly positive anti-JCV antibody status.

CONCLUSION

Long-term anti-JCV antibody status, including seroconverters/-reverters around the cut-off index, is highly predictable by testing three times within short intervals, however, we cannot suggest clearly defined intervals for repetitive testing. The rate of real seroconverters, i.e., new infections with JCV, per year seems lower than previously described.

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.

Effect of dosage reduction on peripheral blood lymphocyte count in patients with multiple sclerosis receiving long-term fingolimod therapy

Of the 19 cases of fingolimod-associated progressive multifocal leukoencephalopathy (PML) reported worldwide by the end of 2017, 4 cases were from Japan. This may indicate that fingolimod sensitivity is higher in the Japanese population than in the western population because the fingolimod dosage used for the prevention of multiple sclerosis (MS) is the same in both populations. Therefore, the laboratory data of nine patients with MS receiving fingolimod treatment for more than 2 years were retrospectively collected. Moreover, the effect of drug holiday was compared between five patients who underwent at least 3 months of dosage reduction via drug holiday after receiving fingolimod for more than 2 years and three patients who underwent drug holiday after receiving fingolimod for less than 2 years. The total, CD3(+), CD4(+), C19(+) lymphocyte counts, the CD4(+)/CD8(+) cell ratio, and the serum IgG concentrations were similar between Japanese patients with MS receiving fingolimod for more than 2 years and Western patients from the previous reports. Recovery of lymphocyte counts in the peripheral blood after fingolimod dosage reduction was worse in some MS patients who received long-term fingolimod treatment than in MS patients who received short-term fingolimod treatment. My findings indicate that the currently used fingolimod dosage may be too high for some Japanese MS patients receiving long-term fingolimod treatment.

Progressive Multifocal Leukoencephalopathy in Primary Immunodeficiencies

PURPOSE

Progressive multifocal leukoencephalopathy (PML) is a rare but severe demyelinating disease caused by the polyomavirus JC (JCV) in immunocompromised patients. We report a series of patients with primary immune deficiencies (PIDs) who developed PML.

METHODS

Retrospective observational study including PID patients with PML. Clinical, immunological, imaging features, and outcome are provided for each patient.

RESULTS

Eleven unrelated patients with PIDs developed PML. PIDs were characterized by a wide range of syndromic or genetically defined defects, mostly with combined B and T cell impairment. Genetic diagnosis was made in 7 patients. Before the development of PML, 10 patients had recurrent infections, 7 had autoimmune and/or inflammatory manifestations, and 3 had a history of malignancies. Immunologic investigations showed CD4⁺ lymphopenia (median 265, range 50-344) in all cases. Six patients received immunosuppressive therapy in the year before PML onset, including prolonged steroid therapy in 3 cases, rituximab in 5 cases, anti-TNF-α therapy, and azathioprine in 1 case each. Despite various treatments, all but 1 patient died after a median of 8 months following PML diagnosis.

CONCLUSION

PML is a rare but fatal complication of PIDs. Many cases are secondary to immunosuppressive therapy warranting careful evaluation before initiation subsequent immunosuppression during PIDs.

Drug-associated progressive multifocal leukoencephalopathy in multiple sclerosis patients

Objective:

To investigate characteristics of multifocal leukoencephalopathy (PML) in multiple sclerosis (MS) patients associated with drugs other than natalizumab since our experience in other disease-modifying drugs (DMD) is still limited.

Methods:

This is a descriptive observational study within the FAERS database, registered between July 2015 and June 2017.

Results:

The primary cohort for the analysis consisted of 100,921 MS patients (mean (standard deviation (sd)) age, 48.9 (12.8) years, 20.9% male). Among them 786 (0.78%) developed PML. The adjusted odds ratio of PML for each drug was as follows; natalizumab 115.72 (95% CI; 83.83, 159.74), fingolimod 4.98 (3.64, 6.81) followed by dimethyl fumarate 1.77 (1.2, 2.62) and rituximab 3.22 (1.07, 9.72). The median time from the start of suspected drugs to the onset of PML for natalizumab and other agents were 1463 and 178 days, respectively. The proportion of PML appeared higher in Japan (2.4%) compared to that in the United States (0.24%).

Conclusion:

The reporting proportion of PML was relatively higher in natalizumab followed by fingolimod, dimethyl fumarate and rituximab. Other characteristics of PML associated with DMDs, including the time to onset and differences in reporting among countries, are described.

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.

Aging and lymphocyte changes by immunomodulatory therapies impact PML risk in multiple sclerosis patients

New potent immunomodulatory therapies for multiple sclerosis (MS) are associated with increased risk for progressive multifocal leukoencephalopathy (PML). It is unclear why a subset of treated patients develops PML, but patient age has emerged as an important risk factor. PML is caused by the JC virus and aging is associated with immune senescence, which increases susceptibility to infection. With the goal of improving PML risk stratification, we here describe the lymphocyte changes that occur with disease-modifying therapies (DMTs) associated with high or moderate risk toward PML in MS patients, how these changes compare to immune aging, and which measures best correlate with risk. We reviewed studies examining how these therapies alter patient immune profiles, which revealed the induction of changes to lymphocyte number and/or function that resemble immunosenescence. Therefore, the immunosuppressive activity of these MS DMTs may be enhanced in the context of an immune system that is already exhibiting features of senescence.

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.

Progressive multifocal leukoencephalopathy during ixazomib-based chemotherapy

Progressive multifocal leukoencephalopathy (pml) is a rare demyelinating disease of the central nervous system that most often affects immunocompromised individuals. It is caused by the reactivation of the John Cunningham virus (jcv), which is found in latent form in the majority of adults. We describe a 59-year-old man with multiple myeloma who developed severe neurological deficits during treatment with ixazomib-based chemotherapy. A diagnosis of pml was established with gadolinium-enhanced magnetic resonance imaging (mri) and by detection of jcv in the cerebrospinal fluid. Despite cessation of chemotherapy and treatment with mirtazapine, he had an inexorable neurological decline and died two months after presenting to hospital. Multiple myeloma and its treatments can predispose patients to opportunistic infections including pml. Although there have been case reports of pml in patients with multiple myeloma treated with bortezomib (a different proteosome inhibitor), this is, to our knowledge, the first documented case of pml in a patient treated with a regimen that includes ixazomib.

Humoral response to John Cunningham virus during pregnancy in multiple sclerosis

BACKGROUND

Pregnancy induces an immunosuppressive state in the mother to ensure immunological acceptance of the foetus. Impairment of cell-mediated immune responses may render the mother susceptible to intracellular pathogens. It is not presently known whether pregnancy alters the immunosurveillance for John Cunningham virus (JCV), an opportunistic pathogen associated with natalizumab treatment for multiple sclerosis (MS).

OBJECTIVE

To evaluate whether the humoral immune response to JCV is altered during pregnancy among MS patients and healthy controls to get insight to potential pregnancy-induced alterations related to immune response to JCV during pregnancy.

METHODS

Serum anti-JCV-antibody-indices (JCV-Ab-index) were determined by a two-step second-generation enzyme-linked immunosorbent assay in 49 MS patients during and after pregnancy and in 49 healthy controls during pregnancy. For comparison, total IgG levels and antibodies against Epstein-Barr, cytomegalo and measles viruses were similarly measured.

RESULTS

The JCV-Ab-indices of MS patients were not altered during the pregnancy (1st vs. 3rd trimester, 0.62 vs. 0.77, p = 0.99). Contrary to this, in the healthy controls JCV-Ab-indices (p = 0.005), antibody levels to the other viruses, and total IgG levels (p < 0.0001) decreased significantly during pregnancy.

CONCLUSIONS

JCV-Ab levels remain unaltered during MS pregnancy, while the total IgG concentration is reduced/diluted due to increasing plasma volumes during the course of pregnancy. This may imply a biologically significant alteration in the immune response to JCV during MS pregnancy.

Smoking is not associated with higher prevalence of JC virus in MS patients

John Cunningham virus (JCV) causes rare, but potentially life-threatening progressive multifocal leukoencephalopathy (PML) in natalizumab-treated multiple sclerosis (MS) patients. Beside JCV index, there is currently no other factor for further risk stratification. Because smoking was reported as potential risk factor for several viral and bacterial infections, we aimed to investigate whether smoking could increase the risk for JCV infection in MS patients. We screened our database of the MS Clinic of the Department of Neurology, Medical University of Innsbruck, Austria, for patients with known smoking status and test result for anti-JCV antibody index as determined by two-step ELISA at Unilabs, Copenhagen, Denmark. In a representative cohort of 200 MS patients with a rate of 36% current smokers plus 6% former smokers, we were not able to detect any association between smoking and JCV status. Furthermore, there was no association between smoking status and anti-JCV antibody index. Smoking does not seem to be a risk factor for JCV infection in MS patients and, therefore, does not represent a suitable marker for PML-risk stratification under treatment with natalizumab.

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%.

Progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is a relatively common complication of HIV disease. In this chapter changes to the epidemiology are discussed along with an update in its pathogenesis and treatment. Immune reconstitution inflammatory syndrome is increasingly frequent in PML; accordingly management strategies and prognosis are detailed.

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.

Natalizumab in the treatment of Crohn's disease patients

INTRODUCTION

Amongst the available therapies for moderate to severe Crohn's disease (CD) patients who are refractory to conventional therapy, anti-TNF blockers are the most effective biological treatment option. However, many patients experience a primary or secondary non-response to anti-TNF therapy, creating the need for alternative biological drugs that target different mechanisms of action and inflammatory pathways. Natalizumab, the first non-anti-TNF biological drug to be approved for treatment of CD patients, is a recombinant humanized antibody that targets the α₄-subunit of both α₄β₁ and α₄β₇ integrins, thus preventing activated leukocyte homing to the intestinal mucosa. Areas covered: This article summarizes the pathophysiological background and the efficacy and safety data of natalizumab, as well as the regulatory issues surrounding it. Expert opinion: Natalizumab represents an effective therapy for refractory CD patients. However, the rare but serious event of progressive multifocal leukoencephalopathy occurrence has compromised its widespread use. The subsequent advent of more specific anti-integrin drugs (i.e. vedolizumab) that carry a more favorable safety profile further reduces the clinical indications for natalizumab. The regulatory process for natalizumab distribution and monitoring in the US may provide a forum for discussion on how to optimally manage use of drugs that offer clinical benefits to patients, while minimizing associated risks.

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.

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.

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.

Progressive Multifocal Leukoencephalopathy in HIV-Uninfected Individuals

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system (CNS) caused by the human neurotropic polyomavirus JC (JCV). The disease occurs virtually exclusively in immunocompromised individuals, and, prior to the introduction of antiretroviral therapy, was seen most commonly in the setting of HIV/AIDS. More recently, however, the incidence of PML in HIV-uninfected persons has increased with broader use of immunosuppressive and immunomodulatory medications utilized in a variety of systemic and neurologic autoimmune disorders. In this review, we discuss the epidemiology and clinical characteristics of PML in HIV-uninfected individuals, as well as diagnostic modalities and the limited treatment options. Moreover, we describe recent findings regarding the neuropathogenesis of PML, with specific focus on the unique association between PML and natalizumab, a monoclonal antibody that prevents trafficking of activated leukocytes into the CNS that is used for the treatment of multiple sclerosis.

Correlation between anti-JC-virus and anti-cytomegalovirus, -Epstein-Barr virus and -measles/-rubella/-varicella-zoster-virus antibodies

Anti-JCV antibody status is used for PML-risk-stratification in MS patients before and during Natalizumab therapy. JCV antibodies can be detected in around 60% of MS patients, however, only a small proportion actually develop PML. As anti-viral antibodies tend to occur unspecifically, the aim of this study was to correlate JCV antibody status and index with other common anti-viral antibodies. A total of 123 samples of MS-patients were tested for anti-JCV antibodies by JCV-Stratify-ELISA at Unilabs, Denmark. The same samples were analyzed for measles, rubella, varicella zoster, EBV, and CMV IgG and IgM antibodies by ELISA, or chemiluminescence-microparticle immunoassay. For all antibody-titers correlations were calculated and group comparisons of JCV-positive and -negative patients were performed. Fifty-three patients (43.1%) were JCV negative and 70 (56.9%) positive. CMV-IgM antibodies were detected in six patients. Otherwise no IgM antibodies were detected. IgG antibodies against measles, rubella, varicella zoster, and EBV were detected in ≥97% of patients and 47 samples (38.2%) tested positive for CMV-IgG. There was no significant correlation between any of the antibody titers including JCV index, however, a significantly higher prevalence (P = 0.003) of CMV-IgG in JCV positive compared to JCV negative patients, whereas no difference was detected for measles, rubella, varicella zoster, and EBV IgG. In conclusion, the JCV antibody response in MS patients seems to be largely independent of any other anti-viral immunity. The only coincidence was found with CMV IgG antibodies which might point towards some immunological cross-reactivity in anti-viral immune response or other mechanisms leading to combined viral infections such as shared transmission. J. Med. Virol. 89:3-9, 2017. © 2016 Wiley Periodicals, Inc.