The spectrum of progressive multifocal leukoencephalopathy: a practical approach

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.

The association between various viral infections and multiple sclerosis: An umbrella review on systematic review and meta-analysis

Multiple Sclerosis (MS) is one of the immune-mediated demyelinating disorders. Multiple components, including the environment and genetics, are possible factors in the pathogenesis of MS. Also, it can be said that infections are a key component of the host's response to MS development. Finally, we evaluated the relationship between different pathogens and MS disease in this umbrella research. We systematically collected and analysed multiple meta-analyses focused on one particular topic. We utilised the Scopus, PubMed, and Web of Science databases starting with inception until 30 May 2023. The methodological quality of the analysed meta-analysis has been determined based on Assessing the Methodological Quality of Systematic Reviews 2 and Grade, and graph construction and statistical analysis were conducted using Comprehensive Meta-Analysis. The Confidence Interval of effect size was 95% in meta-analyses, and p < 0.05 indicated a statistically meaningful relationship. The included studies evaluated the association between MS and 12 viruses containing SARS-CoV-2, Epstein-Barr virus (EBV), Hepatitis B virus, varicella-zoster virus (VZV), human herpesvirus 6 (HHV-6), HHV-7, HHV-8, HSV-1, HSV-2, Cytomegalovirus, Human Papillomavirus, and influenza. SARS-CoV-2, with a 3.74 odds ratio, has a significantly more potent negative effect on MS among viral infections. After that, EBV, HHV-6, HSV-2, and VZV, respectively, with 3.33, 2.81, 1.76, and 1.72 odds ratios, had a significantly negative relationship with MS (p < 0.05). Although the theoretical evidence mostly indicates that EBV has the greatest effect on MS, recent epidemiological studies have challenged this conclusion and put forward possibilities that SARS-CoV-2 is the culprit. Hence, it was necessary to investigate the effects of SARS-CoV-2 and EBV on MS.

Progressive multifocal leukoencephalopathy secondary to idiopathic CD4 lymphocytopenia treated with pembrolizumab

BACKGROUND

Progressive multifocal leukoencephalopathy (PML) is a rare demyelinating disease due to a lytic infection of oligodendrocytes caused by John Cunningham polyoma virus (JCV) infection. Idiopathic CD4+ T-cell lymphocytopenia (ICL) is a very rare cause of PML.

METHODS

We present an individual with PML secondary to ICL treated with 3 doses of pembrolizumab, a Programmed-Death-1 Immune Checkpoint Inhibitor following with complete resolution of symptoms and conduct a review of the literature.

CONCLUSION

This report illustrates the objective clinical and radiological improvement in a patient with PML due to ICL and suggests further study of immune checkpoint inhibitors as potential treatment for patients with PML.

Progressive multifocal leukoencephalopathy: a retrospective study of the last 12 years in a tertiary-care hospital

Our study aims to report on the demographic, incidence rate (IR), clinical, and microbiological characteristics of PML patients diagnosed in our tertiary-care hospital over the past 12 years. In this retrospective observational study, we reviewed all requests for JCPyV PCR in CSF from patients with suspected PML. We collected demographic, clinical, and microbiological data of patients diagnosed with PML. Since 2018, real-time quantitative PCR has been used, whereas prior to 2018, samples were sent to our National Reference Center for qualitative diagnosis. Thirteen patients were diagnosed with PML, with 10 of them having a definitive diagnosis and 3 classified as a possible diagnosis with negative PCR results. Eleven patients had advanced HIV, one had non-Hodgkin's lymphoma, and one had systemic lupus erythematosus. Most of the white matter lesions were located at the cerebral level, although the parenchyma and cerebellum were also affected. The most frequent symptoms were behavioral disorders and hemiparesis. The viral load of JCPyV in cerebrospinal fluid was < 1000 copies/mL in three patients. Six patients received compassionate treatment, and all six patients with definitive PML diagnosis died. Although advanced HIV patients were the most affected by PML in our study, it should also be considered in patients with other underlying diseases. While current PCR tests offer high sensitivity and specificity, false negatives can occur. The prognosis of the disease remains poor, and early multidisciplinary diagnosis-including clinical, microbiological, and neuroimaging assessments-remains crucial for improving neurological damage and prognosis.

Progressive multifocal leukoencephalopathy without overt immunosuppression

Progressive multifocal leukoencephalopathy (PML) is a central nervous system disease caused by the human polyomavirus 2 that usually occurs in a setting of immunodeficiency. PML without overt immunosuppression is considered a rare occurrence but has been described in multiple previous case reports and series. Its prevalence, overall frequency, and prognosis are largely unknown. This is a single-center retrospective review of all University of Florida cases with the ICD10 PML diagnosis code (A81.2). PML without overt immunosuppression was defined as absence of human immunodeficiency virus (HIV) infection, hematological malignancy, immunomodulatory/-suppressive medications, autoimmune conditions with a propensity for PML (sarcoidosis, systemic lupus erythematosus). Cases that did not fulfill criteria for clinically or histologically definite PML were excluded. Of 52 patients with the ICD10 code A 81.2, 17 fulfilled definite diagnostic criteria for PML. Overt immunosuppression was identified in 15/17 (88.2%) cases (10/17 (58.8%): human immunodeficiency virus; 5/17 (29.4%): immunomodulatory/-suppressive medication). Two/seventeen (11.8%) cases were consistent with PML without overt immunosuppression. Possible contributing factors were a preceding dog bite and mild hypogammaglobulinemia M (39 mg/dL) in case 1 and significant alcohol use without evidence for liver disease in case 2. Both cases were fatal within 6 (case 1) and 2 (case 2) months. The results suggest that PML without overt immunosuppression may be more common than previously described. Therefore, PML should be considered even in the absence of overt immunosuppression if clinical and radiographic findings are suggestive of the diagnosis.

Radiological abnormalities in progressive multifocal leukoencephalopathy: Identifying typical and atypical imaging patterns for early diagnosis and differential considerations

Progressive multifocal leukoencephalopathy (PML) is a rare viral central nervous system (CNS) demyelinating disease primarily associated with a compromised immune system. PML is seen mainly in individuals with human immunodeficiency virus, lymphoproliferative disease, and multiple sclerosis. Patients on immunomodulators, chemotherapy, and solid organ or bone marrow transplants are predisposed to PML. Recognition of various PML-associated typical and atypical imaging abnormalities is critical for early diagnosis and differentiating it from other conditions, especially in high-risk populations. Early PML recognition should expedite efforts at immune-system restoration, allowing for a favorable outcome. This review aims to provide a practical overview of radiological abnormalities in PML patients and address differential considerations.

VEGFR-3 signaling restrains the neuron-macrophage crosstalk during neurotropic viral infection

Upon recognizing danger signals produced by virally infected neurons, macrophages in the central nervous system (CNS) secrete multiple inflammatory cytokines to accelerate neuron apoptosis. The understanding is limited about which key effectors regulate macrophage-neuron crosstalk upon infection. We have used neurotropic-virus-infected murine models to identify that vascular endothelial growth factor receptor 3 (VEGFR-3) is upregulated in the CNS macrophages and that virally infected neurons secrete the ligand VEGF-C. When cultured with VEGF-C-containing supernatants from virally infected neurons, VEGFR-3⁺ macrophages suppress tumor necrosis factor α (TNF-α) secretion to reduce neuron apoptosis. Vegfr-3^ΔLBD/ΔLBD (deletion of ligand-binding domain in myeloid cells) mice or mice treated with the VEGFR-3 kinase inhibitor exacerbate the severity of encephalitis, TNF-α production, and neuron apoptosis post Japanese encephalitis virus (JEV) infection. Activating VEGFR-3 or blocking TNF-α can reduce encephalitis and neuronal damage upon JEV infection. Altogether, we show that the inducible VEGF-C/VEGFR-3 module generates protective crosstalk between neurons and macrophages to alleviate CNS viral infection.

Sequelae and mortality in patients with HIV/AIDS and Progressive Multifocal Leukoencephalopathy: Systematic review and case series in the Brazilian Amazon

Background

Progressive Multifocal Leukoencephalopathy (PML) is an opportunistic neurological disease that mainly affects individuals with HIV/AIDS and has high morbidity and mortality, due to its demyelinating characteristic. This co-infection has been reported since the begging of HIV/Aids epidemic with increasing unfavorable outcomes, however, factors associated to sequelae and death are greatly unknown. In this study we aimed to understand factors associated with the main outcomes of individuals diagnosed with PML and HIV/AIDS, in addition to reporting the characteristics of patients presenting to a referral center in infectious diseases in the Brazilian Amazon.

Methods

A systematic review was performed until July 2022, following the PRISMA guidelines, at Medline/Pubmed, Web of Science, Lilacs and Scielo databases using combinations of HIV, Aids, JC Virus and Progressive Multifocal Leukoencephalopathy, with no restriction to publication date. Additional cases, meeting the eligibility criteria, were added from our hospital database, which consisted of patients presenting PML/HIV between 2010 and 2022. A meta-analysis aiming to explore factors associated to sequelae and death was performed. Baseline characteristics were described using mean and standard deviation, or median and interquartile range when appropriate; multivariate analysis was performed to study factors associated to death and sequelae outcomes.

Results

Eighteen patients were diagnosed between 2010 and 2022, of these, 10 had positive PCR for JC virus. In the Systematic Review, 216 studies yielded 235 confirmed cases of co-infection. A total of 245 were included for analysis. The rates of death and sequelae were, respectively, 47.1% (114/242) and 41.2% (54/131). The use of antiretroviral therapy was more associated with a lower chance of death (OR 0.30, 95% CI: 0.11-0.83), while muscle weakness (OR 4.82, 95% CI: 2.07-11.21) and muscle spasms (OR 6.12, 95% CI: 1.05-35.76) were associated with greater chances of sequelae.

Conclusion

Those on antiretroviral therapy appear to be less likely to die, and among those who survive, those who have muscle weakness as a symptom on admission are more likely to develop sequelae. Adherence to ART, as well as a comprehensive clinical evaluation and follow-up may help to improve clinical outcomes and awareness of morbidities.

Management approach including pembrolizumab for fingolimod-associated progressive multifocal leukoencephalopathy in a patient with relapsing-remitting multiple sclerosis

A 62-year-old man with relapsing-remitting multiple sclerosis developed progressive multifocal leukencephalopathy (PML) after 6 years on fingolimod. The fingolimod was immediately discontinued and preexisting mirtazepine increased. Three weeks later, with brain magnetic resonance imaging (MRI) appearances worsening and cerebrospinal fluid (CSF) JC virus (JCV) titres increasing, maraviroc was introduced. At 6 weeks, subtle punctate contrast enhancement raised the possibility of immune reconstitution inflammatory syndrome (IRIS), followed by a single focal-to-generalised tonic clonic seizure and a further deterioration in clinical disability. Mefloquine was commenced alongside three doses of pembrolizumab administered a month apart. Serial CSF examinations and several imaging modalities including spectroscopy and fused FDG-PET-MRI (18F-fluoro-deoxy-glucose-positron emission tomography-magnetic resonance imaging) were used to help distinguish between PML, PML-IRIS and rebound MS activity and guide optimal management at each stage. A handful of small, enhancing ovoid lesions developed between the first two doses of pembrolizumab, probably representative of a mild rebound phenomenon. A sustained improvement became obvious thereafter with CSF JCV-DNA undetectable 16 weeks following fingolimod withdrawal. To our knowledge, this is the first case of combined therapy and use of pembrolizumab in a fingolimod-associated PML.

Multiple sclerosis and the risk of infection: Association of British Neurologists consensus guideline

Infection in people with multiple sclerosis (MS) is of major concern, particularly for those receiving disease-modifying therapies. This article explores the risk of infection in people with MS and provides guidance-developed by Delphi consensus by specialists involved in their management-on how to screen for, prevent and manage infection in this population.

Therapeutic Advances in Multiple Sclerosis

Multiple sclerosis (MS) is an autoimmune disease affecting the central nervous system that causes significant disability and healthcare burden. The treatment of MS has evolved over the past three decades with development of new, high efficacy disease modifying therapies targeting various mechanisms including immune modulation, immune cell suppression or depletion and enhanced immune cell sequestration. Emerging therapies include CNS-penetrant Bruton's tyrosine kinase inhibitors and autologous hematopoietic stem cell transplantation as well as therapies aimed at remyelination or neuroprotection. Therapy development for progressive MS has been more challenging with limited efficacy of current approved agents for inactive disease and older patients with MS. The aim of this review is to provide a broad overview of the current therapeutic landscape for MS.

Use of Pembrolizumab for Treatment of Progressive Multifocal Leukoencephalopathy in People Living with HIV

Progressive Multifocal Leukoencephalopathy (PML) is a demyelinating disease occurring in advanced HIV infection, caused by the reactivation of poliomavirus JC (JCV). The use of pembrolizumab for treatment is based on the inhibition of programmed cell death protein 1 (PD-1), potentially improving the anti JCV-specific response. We used pembrolizumab with combined antiretroviral treatment (cART) on a compassionate-use basis. At each administration, clinical evaluation, MRI and laboratory testing, including CD3, CD4, CD8, PD-1 markers, HIV-RNA and JCV-DNA in cerebrospinal fluid (CSF)/plasma pairs, were performed. The JCV-specific T cell response was analysed by Elispot assay. This study included five HIV patients: four male, median age 43 years (29–52), median CD4 and CD8 count 150 (15–158) and 973 (354–1250) cell/mm3, respectively; median JCV-DNA and HIV-RNA in CSF/plasma pairs 9.540/1.503 cps/mL and 2.230/619 cp/mL, respectively. Overall, patients received between two and seven doses of pembrolizumab. After treatment, we observed JCV-DNA reduction and PD-1 down-regulation both in CSF and in plasma (high in circulating CD4 and CD8 at baseline), which remained stable at low levels in all patients. Three out of five patients showed stability of clinical picture and neuroimaging, while two others died. More data are needed in order to identify predictors of response to therapy.

Progressive multifocal leukoencephalopathy in the context of newer therapies in hematology and review of new treatment strategies

Progressive multifocal leukoencephalopathy (PML) is a rare, often fatal demyelinating disease of the central nervous system (CNS) caused by the reactivation of JC polyomavirus in the CNS. We present a case of a 54-year-old man with follicular lymphoma diagnosed with PML after being treated with anti-CD20 monoclonal antibody-based regimens for several years. Due to the lack of effective treatment choices for PML, the patient was treated with nivolumab, based on recent reports, but succumbed to his disease a few months after diagnosis. In this paper, we focus on reviewing the literature of PML cases correlated with newer agents used in hematology, possible factors affecting disease prognosis, as well as the available data on upcoming therapeutic options for patients with PML. Though newer promising treatments such as anti-PD1 monoclonal antibodies arise, a definitive treatment option is yet to be found. Vigilance, early detection, and prompt intervention play a crucial role in the prognosis of PML in patients with hematological malignancies.

Treating sarcoidosis-associated progressive multifocal leukoencephalopathy with infliximab

Although most of the progressive multifocal leukoencephalopathy cases in sarcoidosis patients are explained by the treatment with immunosuppressive drugs, it is also reported in treatment-naive sarcoidosis patients, which implies a general predisposition of sarcoidosis patients for progressive multifocal leukoencephalopathy. Indeed, it was shown that active sarcoidosis patients have increased regulatory T cell frequencies which could lead to a subsequent systemic immunosuppression. However, if sarcoidosis with systemic changes of T cell subsets frequencies constitute a risk factor for the development of progressive multifocal leukoencephalopathy, which could then be counteracted by sarcoidosis treatment, is not known. In this cohort study, we included, characterized and followed-up six patients with bioptically confirmed definite progressive multifocal leukoencephalopathy and definite or probable sarcoidosis presenting between April 2013 and January 2019, four of them had no immunosuppressive therapy at the time of developing first progressive multifocal leukoencephalopathy symptoms. Analysis of immune cell subsets in these patients revealed significant imbalances of CD4⁺ T cell and regulatory T cell frequencies. Due to the progression of progressive multifocal leukoencephalopathy in four patients, we decided to treat sarcoidosis anticipating normalization of immune cell subset frequencies and thereby improving progressive multifocal leukoencephalopathy. Notably, by treatment with infliximab, an antibody directed against tumour necrosis factor-α, three patients continuously improved clinically, JC virus was no longer detectable in the cerebrospinal fluid and regulatory T cell frequencies decreased. One patient was initially misdiagnosed as neurosarcoidosis and died 9 weeks after treatment initiation due to aspiration pneumonia. Our study provides insight that sarcoidosis can lead to changes in T cell subset frequencies, which predisposes to progressive multifocal leukoencephalopathy. Although immunosuppressive drugs should be avoided in progressive multifocal leukoencephalopathy, paradoxically in patients with sarcoidosis treatment with the immunosuppressive infliximab might restore normal T cell distribution and thereby halt progressive multifocal leukoencephalopathy progression.

Cerebral lesions in hematological malignancies: a case report

Background

Progressive multifocal leukoencephalopathy is a rare central nervous system disease, resulting from reactivation of latent John Cunningham virus. Monoclonal antibodies have recently become a relevant risk factor for developing progressive multifocal leukoencephalopathy.

Case summary

We report the case of a 62-year-old Caucasian man who was admitted to our department in June 2020 because of right homonymous hemianopia. Magnetic resonance imaging findings were first interpreted as an intracranial relapsed lymphoma, so brain biopsy was performed, but no neoplastic cell was found. Histological sample only showed a large number of macrophages. The patient came back to our attention because of the worsening of neurological symptoms. A second magnetic resonance imaging showed widespread lesions suggestive of a demyelinating process. John Cunningham virus DNA was detected by polymerase chain reaction assay of the cerebrospinal fluid (over 9 million units/μL). The patient was treated supportively, but the outcome was poor.

Discussion

A multidisciplinary assessment should be performed for differential diagnosis of cerebral lesions in hematologic malignancies. Progressive multifocal leukoencephalopathy should be suspected in cases of subacute neurological symptoms and imaging findings consistent with it, especially if the patient received immunosuppressive or immunomodulatory drugs.

Beyond antivirals: virus-specific T-cell immunotherapy for BK virus haemorrhagic cystitis and JC virus progressive multifocal leukoencephalopathy

PURPOSE OF REVIEW

The clinical manifestations of the polyomaviruses BK and JC in immunocompromised patients include BK virus (BKV) induced haemorrhagic cystitis and nephropathy, and JC virus (JCV) associated progressive multifocal leukoencephalopathy (PML) and are typically a consequence of impaired adaptive immunity in the host. To date, little clinical success has been achieved with antiviral agents or other drug therapies to treat these conditions. Here we review the methods and outcomes of the most recent clinical studies utilising adoptive immunotherapy with BK and/or JC virus-specific T-cells (VST) as either prophylaxis or treatment alternatives.

RECENT FINDINGS

In the last 12-18 months, several clinical trials have been published in the post-haemopoietic stem cell transplant (HSCT) setting showing good clinical success with the use of VST for treatment of BK viremia ± haemorrhagic cystitis. Between 82 and 100% clinical response has been observed in haemorrhagic cystitis using either third-party or donor-derived VST. The therapy was well tolerated with few cases of graft versus host disease in HSCT recipients, but immune mediated renal allograft loss was observed in one renal transplant recipient. Studies using BKV/JCV VST to treat PML are hindered by few patients who are sufficiently stable to receive VST. In a condition that otherwise carries such poor prognosis, VST were associated with clearance of JC virus, clinical and radiological improvement in some patients. Immune reconstitution inflammatory syndrome was a noted adverse event.

SUMMARY

Restoration of BK and JC virus immunity using VST immunotherapy has shown good clinical outcomes in BKV associated infections. Further evaluation with the administration of VST earlier in the course of disease is warranted for the treatment of BKV associated nephropathy in renal allograft and in JCV PML. In both indications, larger cohorts and standardisation of dosing and outcome measures would be of benefit.

Risk Assessment of Progressive Multifocal Leukoencephalopathy in Multiple Sclerosis Patients during 1 Year of Ocrelizumab Treatment

Background: Progressive multifocal leukoencephalopathy (PML) caused by the JC virus is the main limitation to the use of disease modifying therapies for treatment of multiple sclerosis (MS). Methods: To assess the PML risk in course of ocrelizumab, urine and blood samples were collected from 42 MS patients at baseline (T0), at 6 (T2) and 12 months (T4) from the beginning of therapy. After JCPyV-DNA extraction, a quantitative-PCR (Q-PCR) was performed. Moreover, assessment of JCV-serostatus was obtained and arrangements’ analysis of non-coding control region (NCCR) and of viral capsid protein 1 (VP1) was carried out. Results: Q-PCR revealed JCPyV-DNA in urine at all selected time points, while JCPyV-DNA was detected in plasma at T4. From T0 to T4, JC viral load in urine was detected, increased in two logarithms and, significantly higher, compared to viremia. NCCR from urine was archetypal. Plasmatic NCCR displayed deletion, duplication, and point mutations. VP1 showed the S269F substitution involving the receptor-binding region. Anti-JCV index and IgM titer were found to statistically decrease during ocrelizumab treatment. Conclusions: Ocrelizumab in JCPyV-DNA positive patients is safe and did not determine PML cases. Combined monitoring of ocrelizumab’s effects on JCPyV pathogenicity and on host immunity might offer a complete insight towards predicting PML risk.

[Initial ophthalmic manifestation of a fatal underlying disease : Importance of perimetry in unspecific visual deterioration]

A 55-year-old male patient presented with bilateral blurred vision. Chronic lymphocytic leukemia was generally known in the medical history, which was treated by immunochemotherapy with fludarabine, cyclophosphamide and rituximab. Static perimetry revealed a homonymous hemianopia to the left. The neurological examination was otherwise unremarkable. Progressive multifocal leukoencephalopathy (PML) was diagnosed by cranial magnetic resonance imaging and detection of JC virus DNA in the cerebrospinal fluid. The PML is a rare demyelinating disease of the central nervous system caused by reactivation of the JC virus. It affects patients with HIV, malignant hematological diseases and immunomodulatory therapy. A specific, antiviral treatment does not yet exist. The prognosis of PML is therefore poor. After a progressive course of the disease the patient died 4 months after the diagnosis.

Understanding progressive multifocal leukoencephalopathy: links between milky-way appearance and mismatch T2/FLAIR

BACKGROUND

Magnetic resonance imaging is essential to diagnose progressive multifocal leukoencephalopathy. The broad radiological spectrum may partially be explained by genetic viral mutations and their differential neurotropism. Recent pharmacovigilance-magnetic resonance imaging studies have provided new insight into pathophysiology and radiological markers of early stages. However, how lesions evolve and why certain anatomical locations are more frequently affected remains unknown. We aim to describe a new sign - T2/fluid-attenutated inversion recovery mismatch - as a complementary marker of cavitated lesions and propose a link with the milky-way appearance, a key early sign. Furthermore, we hypothesise viral dissemination routes.

METHODS

We conducted a retrospective longitudinal study from January 2010 to January 2020, to analyse clinical and magnetic resonance imaging features of 13 progressive multifocal leukoencephalopathy individuals at the symptomatic stage (mean age 58.3 years (SD ± 16.8) - 61.5% were women).

RESULTS

The most prevalent pathology was HIV (61.5%) and motor deficit prevailed regarding other symptoms (76.9%). Frontal lobes (76.9%), middle cerebellar peduncle (61.5%), cerebellum (61.5%), and pons (53.8%) were most commonly affected, and the cortico-ponto-cerebellar pathway seemed involved in these patients. Five patients had a pure radiological pattern. Milky-way appearance was the most frequent radiological sign (58.3%). Five patients with milky-way appearance had concomitantly T2/fluid-attenuated inversion recovery mismatch (P = 0.02). This sign showed high sensitivity and specificity (100-71%, P = 0.02) to assess evolved lesions besides diffusion.

CONCLUSION

The possible tract-dependent spread, as well as clinical and genetic, have implications on the MRI variability of progressive multifocal leukoencephalopathy. The milky-way appearance could reflect a transitional phase towards evolved lesions, the latter demonstrated by T2/fluid-attenuated inversion recovery mismatch. Both could be key magnetic resonance imaging signs to diagnose progressive multifocal leukoencephalopathy at the symptomatic stage.

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.

Neuro-ophthalmologic manifestations of multiple sclerosis other than acute optic neuritis

Acute optic neuritis is the most common neuro-opthalmologic manifestation of multiple sclerosis (MS). Treatment with high-dose intravenous corticosteroids accelerates visual recovery, although it has no long-term visual benefit. MS has several others, less common, neuro-ophthalmological manifestations, where corticotherapy may not be the best treatment option. Neuro-ophthalmologic manifestations of MS other than optic neuritis can be divided in afferent and efferent visual pathways, acute and chronic and may be associated with drugs that are employed in MS. The authors propose is to review the neuro-ophthalmologic manifestations of multiple sclerosis other than optic neuritis. Recognition of these leads to a more targeted treatment and may prevent visual deterioration.

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.

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

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

In this Review, Cortese et al. provide an overview of the pathobiology and evolving presentations of progressive multifocal leukoencephalopathy and other diseases caused by JC virus, and discuss emerging immunotherapeutic approaches that could increase survival.

Progressive multifocal leukoencephalopathy (PML) is a rare, debilitating and often fatal disease of the CNS caused by JC virus (JCV).

JCV establishes asymptomatic, lifelong persistent or latent infection in immune competent hosts, but impairment of cellular immunity can lead to reactivation of JCV and PML.

PML most commonly occurs in patients with HIV infection or lymphoproliferative disease and in patients who are receiving natalizumab for treatment of multiple sclerosis.

The clinical phenotype of PML varies and is shaped primarily by the host immune response; changes in the treatment of underlying diseases associated with PML have changed phenotypes over time.

Other clinical manifestations of JCV infection have been described, including granule cell neuronopathy.

Survival of PML depends on reversal of the underlying immunosuppression; emerging immunotherapeutic strategies include use of checkpoint inhibitors and adoptive T cell transfer.

COS-7 cells are a cellular model to monitor polyomavirus JC miR-J1-5p expression

Polyomavirus JC (JCPyV) is a ubiquitous human neurotropic virus that can cause progressive multifocal leukoencephalopathy (PML), sometimes as a consequence of drug treatment for disabling diseases, including Multiple Sclerosis. JCPyV expresses microRNAs (miRNAs), and in particular miR-J1-5p, but at now we have limited knowledge regarding this aspect. In the present study the expression of JCPyV miR-J1-5p was measured in infected COS-7, to verify if and when this miRNA is expressed in a cell model of JCPyV-MAD-4 strain infection. Results showed that miR-J1-5p expression was relatively constant inside the cells from 11 days to 35 days after infection (mean: 4.13 × 10⁵ copies/μg), and became measurable in supernatants 18 days after infection (mean: 7.20 × 10⁴ copies/μl). miR-J1-5p expression in supernatants peaked (3.76 × 10⁵ copies/μl) 25 days after infection and started to decrease 32 days after infection (7.20 × 10⁴ copies/μl). These data show that COS-7 cells, already used as model for JCPyV replication cycle, can be also utilized to study JCPyV miRNAs expression, potentially opening new research avenues for diseases in which current therapeutic approaches could result in severe adverse effects (e.g. Natalizumab-associated JCPyV reactivation in Multiple Sclerosis patients). In these situations monitoring of miR-J1-5p may shed light on the mechanisms of virus reactivation and may help the clarification of the mechanisms responsible for such severe side effects.

Anti-JCV antibody index does not change during ocrelizumab-treatment

Objective

To prospectively assess anti-JCV antibody index (AI) and its relationship to immunoglobulin levels in ocrelizumab-treated MS patients.

Methods

Monocentric prospective observational study over 24 months assessing anti-JCV AI and immunoglobulin levels in MS patients before and after initiation of ocrelizumab.

Results

No significant change in anti-JCV AI titers was observed 458 ± 300 days after initiation of ocrelizumab (n = 45, 0.7 ± 2.21 vs. 0.6 ± 2.06, p = 0.8). Seroconversion occurred in 1/20 initially anti-JCV seronegative patients. There was no correlation between changes in anti-JCV AI and immunoglobulins.

Conclusion

Treatment with ocrelizumab is not associated with an increase in anti-JCV AI titers.

Role of Viruses in the Pathogenesis of Multiple Sclerosis

Multiple sclerosis (MS) is an immune inflammatory disease, where the underlying etiological cause remains elusive. Multiple triggering factors have been suggested, including environmental, genetic and gender components. However, underlying infectious triggers to the disease are also suspected. There is an increasing abundance of evidence supporting a viral etiology to MS, including the efficacy of interferon therapy and over-detection of viral antibodies and nucleic acids when compared with healthy patients. Several viruses have been proposed as potential triggering agents, including Epstein-Barr virus, human herpesvirus 6, varicella-zoster virus, cytomegalovirus, John Cunningham virus and human endogenous retroviruses. These viruses are all near ubiquitous and have a high prevalence in adult populations (or in the case of the retroviruses are actually part of the genome). They can establish lifelong infections with periods of reactivation, which may be linked to the relapsing nature of MS. In this review, the evidence for a role for viral infection in MS will be discussed with an emphasis on immune system activation related to MS disease pathogenesis.

Human Herpesvirus 6 Detection in Alzheimer's Disease Cases and Controls across Multiple Cohorts

The interplay between viral infection and Alzheimer's disease (AD) has long been an area of interest, but proving causality has been elusive. Several recent studies have renewed the debate concerning the role of herpesviruses, and human herpesvirus 6 (HHV-6) in particular, in AD. We screened for HHV-6 detection across three independent AD brain repositories using (1) RNA sequencing (RNA-seq) datasets and (2) DNA samples extracted from AD and non-AD control brains. The RNA-seq data were screened for pathogens against taxon references from over 25,000 microbes, including 118 human viruses, whereas DNA samples were probed for PCR reactivity to HHV-6A and HHV-6B. HHV-6 demonstrated little specificity to AD brains over controls by either method, whereas other viruses, such as Epstein-Barr virus (EBV) and cytomegalovirus (CMV), were detected at comparable levels. These direct methods of viral detection do not suggest an association between HHV-6 and AD.

Case Series: Myelin Oligodendrocyte Glycoprotein-Immunoglobulin G-Related Disease Spectrum

Introduction: Myelin oligodendrocyte glycoprotein-immunoglobulin G (MOG-IgG)-related disease was initially described as a subtype of neuromyelitis optica spectrum disorder (NMOSD) with antibodies against MOG. However, it has recently been described as a separate disease entity with clinical and radiological features that overlap those of multiple sclerosis (MS) and NMOSD; the clinical features of this disease phenotype remain undetermined. We herein report the clinical presentation of nine MOG-IgG-positive patients, not all of whom fulfill the NMOSD criteria, in order to highlight the features and challenges of this condition.

Method: We retrospectively reviewed the records of the London (Ontario) MS clinic to identify patients diagnosed with positive MOG antibodies based on the 2015 NMOSD consensus criteria.

Result: Nine patients were identified, all Caucasian. Seven (78%) were female, and the median age of onset was 41 years (range, 28–69 years); the median Expanded Disability Status Scale score at onset was 3.0 (range, 2.0–4.0). A monophasic course was noted in two (22.2%) patients, while the median number of relapse events was 3 (range 2–5) in 77.8% of the patients. Optic neuritis and transverse myelitis contributed equally as initial manifestations in three individuals (33%), while brainstem relapse was reported in two individuals (22%). The brain magnetic resonance imaging findings were compatible with McDonald's 2010 dissemination in space criteria in three cases (33%). Short myelitis and an (H)-sign were each documented in one patient.

Conclusion: The phenotypes of MOG Ab-positive cases exhibited overlapping features with MS and NMOSD. This finding highlights the importance of screening for anti-MOG in individuals with demyelinating symptoms, in consideration of the possibility of false-positive MOG Ab results.

The Cerebrospinal Fluid in Multiple Sclerosis

Investigation of cerebrospinal fluid (CSF) in the diagnostic work-up in suspected multiple sclerosis (MS) patients has regained attention in the latest version of the diagnostic criteria due to its good diagnostic accuracy and increasing issues with misdiagnosis of MS based on over interpretation of neuroimaging results. The hallmark of MS-specific changes in CSF is the detection of oligoclonal bands (OCB) which occur in the vast majority of MS patients. Lack of OCB has a very high negative predictive value indicating a red flag during the diagnostic work-up, and alternative diagnoses should be considered in such patients. Additional molecules of CSF can help to support the diagnosis of MS, improve the differential diagnosis of MS subtypes and predict the course of the disease, thus selecting the optimal therapy for each patient.