Immune surveillance and response to JC virus infection and PML

Long-term outcome of progressive multifocal leukoencephalopathy with recombinant interleukin-2 treatment and an associated increase in the number of HPyV-2-specific T-cells: a case report

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease caused by reactivation of the human polyomavirus 2 (HPyV-2). PML is associated with a high morbidity and mortality rate and there is currently no standard curative therapy. We report short-term immunologic response and long-term clinical outcomes in a patient diagnosed with follicular lymphoma (FL) who developed PML. Diagnosis of PML was established conclusively based on findings from a brain biopsy. The patient was treated with recombinant interleukin 2 (IL-2) and showed rapid clinical improvement. HPyV-2-specific T-cells were tracked longitudinally and correlation with clinical status, viral load, and radiographic imaging was documented. After the progression of the patient's FL, which required an allogeneic bone marrow transplant, the patient prophylactically received human leukocyte antigen-matched donor-derived HPyV-2 T-cells to prevent the recurrence of the PML as part of a clinical trial. Twelve years after the initial diagnosis of PML, he did not develop a relapse of his PML, supporting data that therapies that increase HPyV-2-specific T-cells, including IL-2, may be effective in the management of PML.

Transforming growth factor β (TGF-β) pathway in the immunopathogenesis of multiple sclerosis (MS); molecular approaches

INTRODUCTION

Multiple sclerosis (MS) is an acute demyelinating disease with an autoimmune nature, followed by gradual neurodegeneration and enervating scar formation. Dysregulated immune response is a crucial dilemma contributing to the pathogenesis of MS. The role of chemokines and cytokines, such as transforming growth factor-β (TGF-β), have been recently highlighted regarding their altered expressions in MS. TGF-β has three isoforms, TGF-β1, TGF-β2, and TGF-β3, that are structurally similar; however, they can show different functions.

RESULTS

All three isoforms are known to induce immune tolerance by modifying Foxp3⁺ regulatory T cells. Nevertheless, there are controversial reports concerning the role of TGF-β1 and 2 in the progression of scar formation in MS. At the same time, these proteins also improve oligodendrocyte differentiation and have shown neuroprotective behavior, two cellular processes that suppress the pathogenesis of MS. TGF-β3 shares the same properties but is less likely contributes to scar formation, and its direct role in MS remains elusive.

DISCUSSION

To develop novel neuroimmunological treatment strategies for MS, the optimal strategy could be the one that causes immune modulation, induces neurogenesis, stimulates remyelination, and prevents excessive scar formation. Therefore, regarding its immunological properties, TGF-β could be an appropriate candidate; however, contradictory results of previous studies have questioned its role and therapeutic potential in MS. In this review article, we provide an overview of the role of TGF-β in immunopathogenesis of MS, related clinical and animal studies, and the treatment potential of TGF-β in MS, emphasizing the role of different TGF-β isoforms.

Progressive multifocal leukoencephalopathy 10 years following transplant: 5HT receptor antagonism as an adjunct to immune reconstitution

We report a case of a patient presenting with subacute neurological symptoms 10 years postkidney transplant. Cognitive deficits included acalculia and left upper limb dysesthesia, progressing to hemiplegic upper motor neuron weakness. Investigations included an MRI with multiple FLAIR hyperintensities, while a lumbar puncture was sterile with negative flow cytometry. Ultimately, PCR testing for John Cunningham virus was positive on cerebrospinal fluid. The diagnosis of progressive multifocal leukoencephalopathy (PML) was confirmed on the basis of the above.Initially, the patient was managed with withdrawal of immunosuppressants and close observation. Mirtazapine was commenced based on case reports of successful use in non-transplant patients; the patient's recovery was temporally related to withdrawal of immunosuppression and increasing mirtazapine dosage. The patient is currently maintained on prednisolone and mirtazapine with stable graft function and improved mobility and cognitive function.

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.

Rubella Virus Infected Macrophages and Neutrophils Define Patterns of Granulomatous Inflammation in Inborn and Acquired Errors of Immunity

Rubella virus (RuV) has recently been found in association with granulomatous inflammation of the skin and several internal organs in patients with inborn errors of immunity (IEI). The cellular tropism and molecular mechanisms of RuV persistence and pathogenesis in select immunocompromised hosts are not clear. We provide clinical, immunological, virological, and histological data on a cohort of 28 patients with a broad spectrum of IEI and RuV-associated granulomas in skin and nine extracutaneous tissues to further delineate this relationship. Combined immunodeficiency was the most frequent diagnosis (67.8%) among patients. Patients with previously undocumented conditions, i.e., humoral immunodeficiencies, a secondary immunodeficiency, and a defect of innate immunity were identified as being susceptible to RuV-associated granulomas. Hematopoietic cell transplantation was the most successful treatment in this case series resulting in granuloma resolution; steroids, and TNF-α and IL-1R inhibitors were moderately effective. In addition to M2 macrophages, neutrophils were identified by immunohistochemical analysis as a novel cell type infected with RuV. Four patterns of RuV-associated granulomatous inflammation were classified based on the structural organization of granulomas and identity and location of cell types harboring RuV antigen. Identification of conditions that increase susceptibility to RuV-associated granulomas combined with structural characterization of the granulomas may lead to a better understanding of the pathogenesis of RuV-associated granulomas and discover new targets for therapeutic interventions.

The Small t Antigen of JC Virus Antagonizes RIG-I-Mediated Innate Immunity by Inhibiting TRIM25's RNA Binding Ability

JC polyomavirus (JCV), a DNA virus that leads to persistent infection in humans, is the causative agent of progressive multifocal leukoencephalopathy, a lethal brain disease that affects immunocompromised individuals. Almost nothing is currently known about how JCV infection is controlled by the innate immune response and, further, whether JCV has evolved mechanisms to antagonize antiviral immunity. Here, we show that the innate immune sensors retinoic acid-inducible gene I (RIG-I) and cGMP-AMP synthase (cGAS) control JCV replication in human astrocytes. We further identify that the small t antigen (tAg) of JCV functions as an interferon (IFN) antagonist by suppressing RIG-I-mediated signal transduction. JCV tAg interacts with the E3 ubiquitin ligase TRIM25, thereby preventing its ability to bind RNA and to induce the K63-linked ubiquitination of RIG-I, which is known to facilitate RIG-I-mediated cytokine responses. Antagonism of RIG-I K63-linked ubiquitination and antiviral signaling is also conserved in the tAg of the related polyomavirus BK virus (BKV). These findings highlight how JCV and BKV manipulate a key innate surveillance pathway, which may stimulate research into designing novel therapies.IMPORTANCE The innate immune response is the first line of defense against viral pathogens, and in turn, many viruses have evolved strategies to evade detection by the host's innate immune surveillance machinery. Investigation of the interplay between viruses and the innate immune response provides valuable insight into potential therapeutic targets against viral infectious diseases. JC polyomavirus (JCV) is associated with a lifelong, persistent infection that can cause a rare neurodegenerative disease, called progressive multifocal leukoencephalopathy, in individuals that are immunosuppressed. The molecular mechanisms of JCV infection and persistence are not well understood, and very little is currently known about the relevance of innate immunity for the control of JCV replication. Here, we define the intracellular innate immune sensors responsible for controlling JCV infection and also demonstrate a novel mechanism by which a JCV-encoded protein acts as an antagonist of the type I interferon-mediated innate immune response.

A case series of persistent lymphopaenia following treatment with fumaric acid esters for psoriasis

WHAT IS KNOWN AND OBJECTIVE

Fumaric acid esters (FAEs) have been used for fifty years to treat moderate-to-severe psoriasis. However, recent case reports of progressive multifocal leukoencephalopathy, associated with FAE-induced lymphopaenia, have been a cause for concern (J Dtsch Dermatol Ges. 2009;7:603).

CASE SERIES

We report six cases of persistent lymphopaenia following cessation of treatment with FAEs, with a mean duration of lymphopaenia of 33 months.

WHAT IS NEW AND CONCLUSION

Given the lack of evidence regarding expected recovery of lymphocyte counts, further research is required to guide physicians in the risk stratification of patients prior to considering treatment with FAEs.

AIDS-related progressive multifocal leukoencephalopathy

INTRODUCTION

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system caused by reactivation of JC virus (JCV).

METHODS

We described the profile of laboratory-confirmed PML cases among AIDS patients.

RESULTS

A total of 43 HIV patients with clinical conditions compatible with PML were obtained; 5 cases were confirmed by JCV testing. The main clinical finding was mental confusion. Median CD4 count was 54 cells/mm³.

CONCLUSIONS

Three of the five confirmed PML cases died; the time between diagnosis and death was 2, 5, and 6 months. It is important to consider JCV infection as a differential diagnosis.

Autophagy in white matter disorders of the CNS: mechanisms and therapeutic opportunities

Autophagy is a constitutive process that degrades, recycles and clears damaged proteins or organelles, yet, despite activation of this pathway, abnormal proteins accumulate in neurons in neurodegenerative diseases and in oligodendrocytes in white matter disorders. Here, we discuss the role of autophagy in white matter disorders, including neurotropic infections, inflammatory diseases such as multiple sclerosis, and in hereditary metabolic disorders and acquired toxic‐metabolic disorders. Once triggered due to cell stress, autophagy can enhance cell survival or cell death that may contribute to oligodendrocyte damage and myelin loss in white matter diseases. For some disorders, the mechanisms leading to myelin loss are clear, whereas the aetiological agent and pathological mechanisms are unknown for other myelin disorders, although emerging studies indicate that a common mechanism underlying these disorders is dysregulation of autophagic pathways. In this review we discuss the alterations in the autophagic process in white matter disorders and the potential use of autophagy‐modulating agents as therapeutic approaches in these pathological conditions. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

Detection of Human polyomavirus 2 (HPyV2) in oyster samples in northern Brazil

Background

Human polyomavirus 2 (HPyV2 or JCPyV) is persistent in the environment due to its excretion in urine and feces; it is detected in samples of wastewater, surface water and drinking water. A lack of basic sanitation and sewage collection results in the presence of this virus in food, especially in oysters, since they are bioaccumulators and are consumed in their natural form, thus posing a risk to human health.

Methods

This study investigated the frequency of HPyV2 in samples of oysters marketed in northeastern Pará State, Brazil, and optimized a real-time PCR (qPCR) protocol for the detection of an endogenous oyster control. A total of 217 oysters in 22 pools from five municipalities in the state of Pará were analyzed. Samples underwent dissection and total maceration of oyster tissue using a viral concentration technique, followed by DNA extraction with phenol-chloroform and amplification of the VP1 region for molecular detection via qPCR.

Results

HPyV2 was detected in 18.2% (4/22) of the pooled samples, with frequencies of 25, 20, 20 and 16% in the municipalities of Salinópolis, Augusto Corrêa, São Caetano de Odivelas and Curuçá, respectively. Notably, the sample pool from the municipality of Bragança did not have detectable HPyV2 and this was the only sampled location with a water treatment station. In this study, Crassostrea genus-specific primers (AFL52 ribosomal RNA gene) of oyster were developed for use as an endogenous control in the qPCR analysis, which will be useful for future studies.

Conclusions

The detection of HPyV2 in oyster samples commercialized in the state of Pará shows the circulation of this virus in the studied municipalities. Thus, it is necessary to implement measures for improving sewage collection and basic sanitation to avoid contamination of water and food with HPyV2.

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.

Four cases of progressive multifocal leukoencephalopathy in iatrogenic immunocompromised patients

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system (CNS) caused by John Cunningham Virus (JCV). We report four PML cases in immunocompromised patients, respectively treated with (1) Natalizumab, (2) Rituximab, (3) autologous stem-cell transplantation, and (4) Tacrolimus. All patients underwent neurological examination, magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS), JCV-DNA research on biological samples, and lymphocytes subpopulation study. All cases presented with motor, behavioural, and cognitive disorders. Visual, sensitive, and cerebellar deficits developed in three cases. MRI revealed widespread progressive demyelinating areas with active borders; three patients presented contrast enhancement. One patient developed inflammatory reconstitution syndrome (IRIS). At MRS, all cases presented decreased N-acetyl-aspartate (NAA) and three cases showed increased choline (Cho). In one patient, plasma and urine tested positive for JCV-DNA, while cerebrospinal fluid (CSF) analysis confirmed JCV in two patients. The fourth patient had a low JCV-DNA blood titer and brain biopsy showed subacute necrosis. Two patients had abnormal lymphocyte subpopulations. Three patients underwent therapy with Mirtazapine, one of whom received Mefloquine in add-on. No clinical response was registered. Clinical onset, MRI and MRS were highly suggestive of PML in all patients, despite three cases presented contrast enhancement. In three cases JCV-DNA detection in biological samples confirmed the diagnosis. The fourth patient fulfilled diagnosis of “presumptive PML”. Our data confirm the importance to complete the diagnostic workup despite the presence of findings not completely consistent with classical PML. We hypothesize that atypical characteristics could due to the clinical conditions leading to PML.

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Four cases of PML in iatrogenic immunocompromised patients.

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Clinical presentation was typical for PML.

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Diagnostic findings were not completely consistent with classical PML.

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Atypical findings do not exclude diagnosis when clinical data are highly suggestive.

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It is necessary to improve the diagnostic and therapeutic management of patients.

Atovaquone Inhibits Arbovirus Replication through the Depletion of Intracellular Nucleotides

Arthropod-borne viruses represent a significant public health threat worldwide, yet there are few antiviral therapies or prophylaxes targeting these pathogens. In particular, the development of novel antivirals for high-risk populations such as pregnant women is essential to prevent devastating disease such as that which was experienced with the recent outbreak of Zika virus (ZIKV) in the Americas. One potential avenue to identify new and pregnancy-acceptable antiviral compounds is to repurpose well-known and widely used FDA-approved drugs. In this study, we addressed the antiviral role of atovaquone, an FDA Pregnancy Category C drug and pyrimidine biosynthesis inhibitor used for the prevention and treatment of parasitic infections. We found that atovaquone was able to inhibit ZIKV and chikungunya virus virion production in human cells and that this antiviral effect occurred early during infection at the initial steps of viral RNA replication. Moreover, we were able to complement viral replication and virion production with the addition of exogenous pyrimidine nucleosides, indicating that atovaquone functions through the inhibition of the pyrimidine biosynthesis pathway to inhibit viral replication. Finally, using an ex vivo human placental tissue model, we found that atovaquone could limit ZIKV infection in a dose-dependent manner, providing evidence that atovaquone may function as an antiviral in humans. Taken together, these studies suggest that atovaquone could be a broad-spectrum antiviral drug and a potential attractive candidate for the prophylaxis or treatment of arbovirus infection in vulnerable populations, such as pregnant women and children.IMPORTANCE The ability to protect vulnerable populations such as pregnant women and children from Zika virus and other arbovirus infections is essential to preventing the devastating complications induced by these viruses. One class of antiviral therapies may lie in known pregnancy-acceptable drugs that have the potential to mitigate arbovirus infections and disease, yet this has not been explored in detail. In this study, we show that the common antiparasitic drug atovaquone inhibits arbovirus replication through intracellular nucleotide depletion and can impair ZIKV infection in an ex vivo human placental explant model. Our study provides a novel function for atovaquone and highlights that the rediscovery of pregnancy-acceptable drugs with potential antiviral effects can be the key to better addressing the immediate need for treating viral infections and preventing potential birth complications and future disease.

TRPM2 Exacerbates Central Nervous System Inflammation in Experimental Autoimmune Encephalomyelitis by Increasing Production of CXCL2 Chemokines

Multiple sclerosis (MS) is a chronic inflammatory disorder of the CNS characterized by demyelination and axonal injury. Current therapies that mainly target lymphocytes do not fully meet clinical need due to the risk of severe side effects and lack of efficacy against progressive MS. Evidence suggests that MS is associated with CNS inflammation, although the underlying molecular mechanism is poorly understood. Transient receptor potential melastatin 2 (TRPM2), a Ca²⁺-permeable nonselective cation channel, is expressed at high levels in the brain and by immune cells, including monocyte lineage cells. Here, we show that TRPM2 plays a pathological role in experimental autoimmune encephalomyelitis (EAE), an animal model of MS. Knockout (KO) or pharmacological inhibition of TRPM2 inhibited progression of EAE and TRPM2-KO mice showed lower activation of Iba1-immunopositive monocyte lineage cells and neutrophil infiltration of the CNS than WT mice. Moreover, CXCL2 production in TRPM2-KO mice was significantly reduced at day 14, although the severity of EAE was the same as that in WT mice at that time point. In addition, we used BM chimeric mice to show that TRPM2 expressed by CNS-infiltrating macrophages contributes to progression of EAE. Because CXCL2 induces migration of neutrophils, these results indicate that reduced expression of CXCL2 in the CNS suppresses neutrophil infiltration and slows progression of EAE in TRPM2-KO mice. Together, the results suggest that TRPM2 plays an important role in progression of EAE pathology and shed light on its putative role as a therapeutic target for MS.SIGNIFICANCE STATEMENT Current therapies for multiple sclerosis (MS), which mainly target lymphocytes, carry the risk of severe side effects and lack efficacy against the progressive form of the disease. Here, we found that the transient receptor potential melastatin 2 (TRPM2) channel, which is abundantly expressed in CNS-infiltrating macrophages, plays a crucial role in development of experimental autoimmune encephalomyelitis (EAE), an animal model of MS. EAE progression was suppressed by Knockout (KO) or pharmacological inhibition of TRPM2; this was attributed to a reduction in CXCL2 chemokine production by CNS-infiltrating macrophages in TRPM2-KO mice, resulting in suppression of neutrophil infiltration into the CNS. These results reveal an important role of TRPM2 in the pathogenesis of EAE and shed light on its potential as a therapeutic target.

Frequency of JC Virus Appearance in the Urine of Post-Transplantation Patients

Polyomaviruses are common viruses that induce various infections in many mammalian species, including humans. The best-known viruses of this kind are BKV and JCV. The aim of the study was to analyze the incidence of infection caused by JCV in a group of patients after kidney or bone marrow transplant, and to analyze JCV genetic diversity in post-transplantation recipients. The study group included 81 patients after kidney transplantation treated in the Independent Public Teaching Hospital No 4 in Lublin and a group of 24 patients after marrow transplantation from the Children's Clinical Hospital of Lublin. The research material included 105 DNA probes from urine samples that were tested via the PCR method for the presence of JCV genetic material. Amplification products were separated in agarose gel, positive PCR products were subjected to purification and the pure product was sent to sequencing. Pearson's chi-square test was used to investigate the relationship between the prevalence of JCV viruria and study group and gender. Statistical significance was defined as p < 0.05. A JCV positive result was discovered in 27.6% of all samples. In the group of adults, 34.6% were positive, while in children, this was 3.4%. Among all patients, only 8 women were infected with the JC virus, while 21 men were. We saw that the incidence of infection caused by the JC virus increases with age. Moreover, JCV DNA is more frequently isolated from men than from women. JCV infections are also a more common cause of infections in patients after renal transplantation than in bone marrow transplant patients

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.

Diagnosis and Treatment of Progressive Multifocal Leukoencephalopathy Associated with Multiple Sclerosis Therapies

Progressive multifocal leukoencephalopathy (PML) is a rare, but serious, complication encountered in patients treated with a select number of disease-modifying therapies (DMTs) utilized in treating multiple sclerosis (MS). PML results from a viral infection in the brain for which the only demonstrated effective therapy is restoring the perturbed immune system-typically achieved in the patient with MS by removing the offending therapeutic agent or, in the case of HIV-associated PML, treatment with highly active antiretroviral therapies. Other therapies for PML remain either ineffective or experimental. Significant work to understand the virus and host interaction has been undertaken, but lack of an animal model for the disorder has significantly hindered progress, especially with respect to development of treatments. Strategies to limit risk of PML with natalizumab, a drug that carries a uniquely high risk for the development of the disorder, have been developed. Identifying factors such as positive JC virus antibody status that increase PML risk, at least in theory, should decrease the incidence rate of the disease. Whether other risk factors for PML can be identified and validated or unique strategies should be employed in association with other DMTs that predispose to PML and whether this has a salutary effect on outcome remains to be demonstrated. Identifying PML early, then promptly eliminating drug in the case of natalizumab-associated PML has demonstrated better outcomes, but the complication of PML continues to carry significant morbidity and mortality. While the scientific community has yet to identify targeted therapy with proven efficacy against JCV or PML there are several candidates being studied.

JC Polyomavirus Attachment and Entry: Potential Sites for PML Therapeutics

PURPOSE OF REVIEW

JC polyomavirus (JCPyV) is a significant human pathogen that causes an asymptomatic infection in the kidney in the majority of the population. In immunosuppressed individuals, the virus can become reactivated and spread to the brain, causing the fatal, demyelinating disease progressive multifocal leukoencephalopathy (PML). There are currently limited treatment options for this fatal disease. Attachment to receptors and entry into host cells are the initiating events in JCPyV infection and therefore an attractive target for therapeutics to prevent or treat PML. This review provides the current understanding of JCPyV attachment and entry events and the potential therapeutics to target these areas.

RECENT FINDINGS

JCPyV attachment and entry to host cells is mediated by α2,6-linked lactoseries tetrasaccharide c (LSTc) and 5-hydroxytryptamine receptors (5-HT₂Rs), respectively, and subsequent trafficking to the endoplasmic reticulum is required for infection. Recently, vaccines, monoclonal antibodies, and small molecules have shown promise as anti-viral and PML therapies.

SUMMARY

This review summarizes our current understanding of JCPyV attachment, entry, and trafficking and the development of potential PML therapeutics that inhibit these critical steps in JCPyV infection.

Matrix metalloproteinase 9 is decreased in natalizumab-treated multiple sclerosis patients at risk for progressive multifocal leukoencephalopathy

OBJECTIVE

To identify biomarkers associated with the development of progressive multifocal leukoencephalopathy (PML) in multiple sclerosis (MS) patients treated with natalizumab (NTZ).

METHODS

Relapsing-remitting MS patients who developed PML under NTZ therapy (pre-PML) and non-PML NTZ-treated patients (NTZ-ctr) were included in the study. Cryopreserved peripheral blood mononuclear cells and serum samples collected at baseline, at 1- and 2-year treated time points, and during PML were analyzed for gene expression by RNA sequencing and for serum protein levels by Luminex and enzyme-linked immunosorbent assays, respectively.

RESULTS

Among top differentially expressed genes in the RNA sequencing between pre-PML and NTZ-ctr patients, pathway analysis revealed a high representation of genes belonging to the following categories: proangiogenic factors (MMP9, VEGFA), chemokines (CXCL1, CXCL5, IL8, CCL2), cytokines (IL1B, IFNG), and plasminogen- and coagulation-related molecules (SERPINB2, PLAU, PLAUR, TFPI, THBD). Serum protein levels for these candidates were measured in a 2-step manner in a screening cohort and a validation cohort of pre-PML and NTZ-ctr patients. Only matrix metalloproteinase 9 (MMP9) was validated; in pre-PML patients, MMP9 protein levels were significantly reduced at baseline compared with NTZ-ctr patients, and levels remained lower at later time points during NTZ treatment.

INTERPRETATION

The results from this study suggest that the proangiogenic factor MMP9 may play a role as a biomarker associated with the development of PML in MS patients treated with NTZ. Ann Neurol 2017;82:186-195.

PET Imaging of 18F-FDG, 11C-methionine, 11C-flumazenil, and 11C-4DST in Progressive Multifocal Leukoencephalopathy

The use of positron emission tomography (PET) imaging in progressive multifocal leukoencephalopathy (PML) has rarely been reported. We herein report a set of PET images in a 63-year-old patient with PML. In PML lesions, the uptake of ¹⁸F-fluorodeoxyglucose, ¹¹C-methionine, ¹¹C-flumazenil, and [methyl-¹¹C]4'-thiothymidine was decreased, increased, decreased, and unchanged, respectively. These results suggest that glucose metabolism decreased, protein synthesis increased, neuronal integrity decreased, and the DNA synthesis and cellular proliferation of host cells were not activated in PML lesions. These results may reflect very little infiltration by inflammatory cells and active infection with JC virus in this case.

Immune reconstitution inflammatory syndrome in HIV infection: taking the bad with the good

In this review, we will describe the immunopathogies of immune reconstitution inflammatory syndrome, IRIS. IRIS occurs in a small subset of HIV patient, initiating combination antiretroviral therapy (ART), where immune reconstitution becomes dysregulated, resulting in an overly robust antigen-specific inflammatory reaction. We will discuss IRIS in terms of the associated coinfections: mycobacteria, cryptococci, and viruses.

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

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

Expression of Signaling Molecules in Progressive Multifocal Leukoencephalopathy

INTRODUCTION

Progressive multifocal leukoencephalopathy (PML) is a debilitating demyelinating disease of the CNS caused by the infection and destruction of glial cells by JC virus (JCV) and is an AIDS-defining disease. Infection with JCV is common and most people acquire antibodies early in life. After initial infection, JCV remains in an asymptomatic persistent state and can be detected by PCR in many tissues including brain. A major question in PML pathogenesis is how the virus reactivates from persistence in HIV-1/AIDS. Our studies with primary cultures of glial cells have implicated transcription factors NF-κB and NFAT4, which bind to a unique site in the JCV noncoding control region and stimulate viral gene expression. Furthermore, these transcription factors are controlled by pathways downstream of proinflammatory cytokines, e.g., TNF-α activates NF-κB and stimulates JCV transcription.

OBJECTIVES

We hypothesize that HIV-1/PML initiation may involve reactivation of JCV by cytokine disturbances in the brain such as occur in HIV-1/AIDS. In this study, the objective was to evaluate HIV-1/PML clinical samples for expression of TNF-α and its receptors and subcellular localization of NF-κB p65 and NFAT4 compared to non-PML controls.

METHODS

We evaluated HIV-1/PML clinical samples and non-PML controls for expression of TNF-α and its receptors and subcellular localization of NF-κB p65 and NFAT4 using Western blot and immunohistochemistry.

RESULTS

Consistent with our hypothesis, compared to non-PML controls, HIV-1/PML tissue has high levels of TNF-α and TNFR1 expression and NF-κB and NFAT4 were preferentially localized to the nucleus.

CONCLUSION

The involvement of TNF-α/NF-κB/NFAT4 signaling in JCV regulation that we reported from experiments in cultured human glial cells may be clinically relevant in PML.

Pur-Alpha Induces JCV Gene Expression and Viral Replication by Suppressing SRSF1 in Glial Cells

Objective

PML is a rare and fatal demyelinating disease of the CNS caused by the human polyomavirus, JC virus (JCV), which occurs in AIDS patients and those on immunosuppressive monoclonal antibody therapies (mAbs). We sought to identify mechanisms that could stimulate reactivation of JCV in a cell culture model system and targeted pathways which could affect early gene transcription and JCV T-antigen production, which are key steps of the viral life cycle for blocking reactivation of JCV. Two important regulatory partners we have previously identified for T-antigen include Pur-alpha and SRSF1 (SF2/ASF). SRSF1, an alternative splicing factor, is a potential regulator of JCV whose overexpression in glial cells strongly suppresses viral gene expression and replication. Pur-alpha has been most extensively characterized as a sequence-specific DNA- and RNA-binding protein which directs both viral gene transcription and mRNA translation, and is a potent inducer of the JCV early promoter through binding to T-antigen.

Methods and Results

Pur-alpha and SRSF1 both act directly as transcriptional regulators of the JCV promoter and here we have observed that Pur-alpha is capable of ameliorating SRSF1-mediated suppression of JCV gene expression and viral replication. Interestingly, Pur-alpha exerted its effect by suppressing SRSF1 at both the protein and mRNA levels in glial cells suggesting this effect can occur independent of T-antigen. Pur-alpha and SRSF1 were both localized to oligodendrocyte inclusion bodies by immunohistochemistry in brain sections from patients with HIV-1 associated PML. Interestingly, inclusion bodies were typically positive for either Pur-alpha or SRSF1, though some cells appeared to be positive for both proteins.

Conclusions

Taken together, these results indicate the presence of an antagonistic interaction between these two proteins in regulating of JCV gene expression and viral replication and suggests that they play an important role during viral reactivation leading to development of PML.

Anti-JC virus seroprevalence in a Finnish MS cohort

BACKGROUND

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

Progressive Multifocal Leukoencephalopathy in Primary Immune Deficiencies: Stat1 Gain of Function and Review of the Literature

BACKGROUND

Progressive multifocal leukoencephalopathy (PML) is a rare, severe, otherwise fatal viral infection of the white matter of the brain caused by the polyomavirus JC virus, which typically occurs only in immunocompromised patients. One patient with dominant gain-of-function (GOF) mutation in signal transducer and activator of transcription 1 (STAT1) with chronic mucocutaneous candidiasis and PML was reported previously. We aim to identify the molecular defect in 3 patients with PML and to review the literature on PML in primary immune defects (PIDs).

METHODS

STAT1 was sequenced in 3 patients with PML. U3C cell lines were transfected with STAT1 and assays to search for STAT1 phosphorylation, transcriptional response, and target gene expression were performed.

RESULTS

We identified 3 new unrelated cases of PML in patients with GOF STAT1 mutations, including the novel STAT1 mutation, L400Q. These STAT1 mutations caused delayed STAT1 dephosphorylation and enhanced interferon-gamma-driven responses. In our review of the literature regarding PML in primary immune deficiencies we found 26 cases, only 54% of which were molecularly characterized, the remainder being syndromically diagnosed only.

CONCLUSIONS

The occurrence of PML in 4 cases of STAT1 GOF suggests that STAT1 plays a critical role in the control of JC virus in the central nervous system.

Treatment options for progressive multifocal leukoencephalopathy in HIV-infected persons: current status and future directions

Progressive multifocal encephalopathy (PML) caused by JC virus was frequently encountered in AIDS patients before combination antiretroviral therapy (cART). Incidence decreased and the outcome improved with cART. The immune reconstitution with cART is beneficial for HIV-infected patients and is an effective treatment for PML. However, when it is excessive an inflammatory response immune syndrome might occur with deterioration of PML. So far, no specific therapy has proven efficacious in small clinical trials in spite of some optimistic case reports. Combination of drugs targeted at different stages of JC virus life cycle seems to have a better effect. Passive and active immune therapies, immune competence "boosters" appear promising. New future approaches such as gene editing are not far away.

Diagnostic assays for polyomavirus JC and progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is a devastating and often fatal demyelinating disease of the central nervous system for which effective therapies are lacking. It is caused by the replication of polyomavirus JC (JCV) in the oligodendrocytes and astrocytes leading to their cytolytic death and loss of myelin from the subcortical white matter. While the virus is very common in human populations worldwide, the incidence of the disease is very low and confined almost exclusively to individuals with some form of immunological dysfunction. However, the number of people who constitute the at-risk population is growing larger and includes individuals with HIV-1/AIDS and patients receiving immunomodulatory therapies such as multiple sclerosis patients treated with natalizumab. Further adding to the public health significance of this disease are the difficulties encountered in the diagnosis of PML and the lack of useful biomarkers for PML progression. In this review, we examine the diagnostic assays that are available for different aspects of the JCV life cycle, their usefulness and drawbacks, and the prospects for improvements.

Animal Models for Progressive Multifocal Leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is a severe demyelinating disease of the CNS caused by the human polyomavirus JC (JCV). JCV replication occurs only in human cells and investigation of PML has been severely hampered by the lack of an animal model. The common feature of PML is impairment of the immune system. The key to understanding PML is working out the complex mechanisms that underlie viral entry and replication within the CNS and the immunosurveillance that suppresses the virus or allows it to reactivate. Early models involved the simple inoculation of JCV into animals such as monkeys, hamsters, and mice. More recently, mouse models transgenic for the gene encoding the JCV early protein, T-antigen, a protein thought to be involved in the disruption of myelin seen in PML, have been employed. These animal models resulted in tumorigenesis rather than demyelination. Another approach is to use animal polyomaviruses that are closely related to JCV but able to replicate in the animal such as mouse polyomavirus and SV40. More recently, novel models have been developed that involve the engraftment of human cells into the animal. Here, we review progress that has been made to establish an animal model for PML, the advances and limitations of different models and weigh future prospects.

Persistence and pathogenesis of the neurotropic polyomavirus JC

Many neurological diseases of the central nervous system (CNS) are underpinned by malfunctions of the immune system, including disorders involving opportunistic infections. Progressive multifocal leukoencephalopathy (PML) is a lethal CNS demyelinating disease caused by the human neurotropic polyomavirus JC (JCV) and is found almost exclusively in individuals with immune disruption, including patients with human immunodeficiency virus/acquired immunodeficiency syndrome, patients receiving therapeutic immunomodulatory monoclonal antibodies to treat conditions such as multiple sclerosis, and transplant recipients. Thus, the public health significance of this disease is high, because of the number of individuals constituting the at-risk population. The incidence of PML is very low, whereas seroprevalence for the virus is high, suggesting infection by the virus is very common, and so it is thought that the virus is restrained but it persists in an asymptomatic state that can only occasionally be disrupted to lead to viral reactivation and PML. When JCV actively replicates in oligodendrocytes and astrocytes of the CNS, it produces cytolysis, leading to formation of demyelinated lesions with devastating consequences. Defining the molecular nature of persistence and events leading to reactivation of the virus to cause PML has proved to be elusive. In this review, we examine the current state of knowledge of the JCV life cycle and mechanisms of pathogenesis. We will discuss the normal course of the JCV life cycle including transmission, primary infection, viremia, and establishment of asymptomatic persistence as well as pathogenic events including migration of the virus to the brain, reactivation from persistence, viral infection, and replication in the glial cells of the CNS and escape from immunosurveillance.

Immunology of progressive multifocal leukoencephalopathy

The high prevalence of asymptomatic JC polyomavirus (JCV) infection in the general population indicates coexistence with the human host and efficient immune control in healthy individuals. For unknown reasons, kidney-resident archetypic JCV strains can turn into neurotropic JCV strains which in hereditary or acquired states of immunodeficiency cause opportunistic infection and cytolytic destruction of glial cells or granule cell neurons resulting in progressive multifocal demyelination in the central nervous system (CNS) or cerebellar atrophy, respectively. Immunomodulatory or immunosuppressive therapies with specific monoclonal antibodies including natalizumab, efalizumab, and rituximab have increased the risk of progressive multifocal leukoencephalopathy (PML) among treated patients, highlighting that symptomatic JCV infection of the CNS is associated with disturbances of adaptive immunity affecting B cells, antibodies, and CD4(+) and/or CD8(+) T cells. To date, no specific therapy to overcome PML is available and the only way to eliminate the virus from the CNS is to reconstitute global immune function. However, since the identification of JCV as the causative agent of PML 40 years ago, it is still not fully understood which components of the immune system prevent the development of PML and which immune mechanisms are involved in eliminating the virus from the CNS. This review gives an update about adaptive JCV-specific immune responses.

The importance of mouse models to define immunovirologic determinants of progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is a severely debilitating and often fatal demyelinating disease of the central nervous system (CNS) in immunosuppressed individuals caused by JC polyomavirus (JCV), a ubiquitous human pathogen. Demyelination results from lytically infected oligodendrocytes, whose clearance is impaired in the setting of depressed JCV-specific T cell-mediated CNS surveillance. Although mutations in the viral capsid and genomic rearrangements in the viral non-coding region appear to set the stage for PML in the immunosuppressed population, mechanisms of demyelination and CNS antiviral immunity are poorly understood in large part due to absence of a tractable animal model that mimics PML neuropathology in humans. Early studies using mouse polyomavirus (MPyV) in T cell-deficient mice demonstrated productive viral replication in the CNS and demyelination; however, these findings were confounded by spinal cord compression by virus-induced vertebral bone tumors. Here, we review current literature regarding animal models of PML, focusing on current trends in antiviral T cell immunity in non-lymphoid organs, including the CNS. Advances in our understanding of polyomavirus lifecycles, viral and host determinants of persistent infection, and T cell-mediated immunity to viral infections in the CNS warrant revisiting polyomavirus CNS infection in the mouse as a bona fide animal model for JCV-PML.

Microenvironmental clues for glioma immunotherapy

Gliomas have been viewed for decades as inaccessible for a meaningful antitumor immune response as they grow in a sanctuary site protected from infiltrating immune cells. Moreover, the glioma microenvironment constitutes a hostile environment for an efficient antitumor immune response as glioma-derived factors such as transforming growth factor β and catabolites of the essential amino acid tryptophan paralyze T-cell function. There is growing evidence from preclinical and clinical studies that a meaningful antitumor immunity exists in glioma patients and that it can be activated by vaccination strategies. As a consequence, the concept of glioma immunotherapy appears to be experiencing a renaissance with the first phase 3 randomized immunotherapy trials entering the clinical arena. On the basis of encouraging results from other tumor entities using immunostimulatory approaches by blocking endogenous T-cell suppressive pathways mediated by cytotoxic T-lymphocyte antigen 4 or programmed cell death protein 1/programmed cell death protein 1 ligand 1 with humanized antibodies, there is now a realistic and promising option to combine active immunotherapy with agents blocking the immunosuppressive microenvironment in patients with gliomas to allow a peripheral antitumor immune response induced by vaccination to become effective. Here we review the current clinical and preclinical evidence of antimicroenvironment immunotherapeutic strategies in gliomas.