A study of mefloquine treatment for progressive multifocal leukoencephalopathy: results and exploration of predictors of PML outcomes

Unveiling the Enigma: John Cunningham Virus-Associated Progressive Multifocal Leukoencephalopathy in an Immunocompetent Individual

Progressive multifocal leukoencephalopathy (PML) is considered an often fatal, demon-leading disease primarily associated with immunosuppression. Immunocompromised individuals predominantly exhibit this manifestation, while immunocompatible patients rarely encounter it. We present a unique case of PML in an immunocompetent individual who initially presented with stroke-like symptoms, received management, and was subsequently discharged. He returned to our hospital a few days later with similar complaints, prompting further investigations that revealed PML, a condition often overlooked, especially in individuals with an intact immune system. Although he received successful treatment with mefloquine and other anti-malarial medications and followed up on an outpatient basis, his subsequent outcome was unfavourable. As a result, this case emphasises the importance of having PML as a significant differential and therapeutic option.

Upregulation of the NKG2D Ligand ULBP2 by JC Polyomavirus Infection Promotes Immune Recognition by Natural Killer Cells

BACKGROUND

JC polyomavirus (JCPyV) causes progressive multifocal leukoencephalopathy (PML), a potentially fatal complication of severe immune suppression with no effective treatment. Natural killer (NK) cells play critical roles in defense against viral infections; however, NK-cell response to JCPyV infection remains unexplored.

METHODS

NK- and T-cell responses against the JCPyV VP1 were compared using intracellular cytokine staining upon stimulation with peptide pools. A novel flow cytometry-based assay was developed to determine NK-cell killing efficiency of JCPyV-infected astrocyte-derived SVG-A cells. Blocking antibodies were used to evaluate the contribution of NK-cell receptors in immune recognition of JCPyV-infected cells.

RESULTS

In about 40% of healthy donors, we detected robust CD107a upregulation and IFN-γ production by NK cells, extending beyond T-cell responses. Next, using the NK-cell-mediated killing assay, we showed that coculture of NK cells and JCPyV-infected SVG-A cells leads to a 60% reduction in infection, on average. JCPyV-infected cells had enhanced expression of ULBP2-a ligand for the activating NK-cell receptor NKG2D, and addition of NKG2D blocking antibodies decreased NK-cell degranulation.

CONCLUSIONS

NKG2D-mediated activation of NK cells plays a key role in controlling JCPyV replication and may be a promising immunotherapeutic target to boost NK-cell anti-JCPyV activity.

Biomarkers for progressive multifocal leukoencephalopathy: emerging data for use of JC virus DNA copy number in clinical trials

Progressive multifocal leukoencephalopathy is a rare but devastating demyelinating disease caused by the JC virus (JCV), for which no therapeutics are approved. To make progress towards addressing this unmet medical need, innovations in clinical trial design are needed. Quantitative JCV DNA in CSF has the potential to serve as a valuable biomarker of progressive multifocal leukoencephalopathy disease and treatment response in clinical trials to expedite therapeutic development, as do neuroimaging and other fluid biomarkers such as neurofilament light chain. Specifically, JCV DNA in CSF could be used in clinical trials as an entry criterion, stratification factor, or predictor of clinical outcomes. Insights from the investigation of candidate biomarkers for progressive multifocal leukoencephalopathy might inform approaches to biomarker development for other rare diseases.

Structural vaccinology, molecular simulation and immune simulation approaches to design multi-epitopes vaccine against John Cunningham virus

The JCV (John Cunningham Virus) is known to cause progressive multifocal leukoencephalopathy, a condition that results in the formation of tumors. Symptoms of this condition such as sensory defects, cognitive dysfunction, muscle weakness, homonosapobia, difficulties with coordination, and aphasia. To date, there is no specific and effective treatment to completely cure or prevent John Cunningham polyomavirus infections. Since the best way to control the disease is vaccination. In this study, the immunoinformatic tools were used to predict the high immunogenic and non-allergenic B cells, helper T cells (HTL), and cytotoxic T cells (CTL) epitopes from capsid, major capsid, and T antigen proteins of JC virus to design the highly efficient subunit vaccines. The specific immunogenic linkers were used to link together the predicted epitopes and subjected to 3D modeling by using the Robetta server. MD simulation was used to confirm that the newly constructed vaccines are stable and properly fold. Additionally, the molecular docking approach revealed that the vaccines have a strong binding affinity with human TLR-7. The codon adaptation index (CAI) and GC content values verified that the constructed vaccines would be highly expressed in E. coli pET28a (+) plasmid. The immune simulation analysis indicated that the human immune system would have a strong response to the vaccines, with a high titer of IgM and IgG antibodies being produced. In conclusion, this study will provide a pre-clinical concept to construct an effective, highly antigenic, non-allergenic, and thermostable vaccine to combat the infection of the John Cunningham virus.

Identifying CNS infections in transplantation and immunomodulatory therapy

Opportunistic central nervous system (CNS) infections are a significant cause of morbidity and mortality in immunocompromized patients, including those undergoing transplantation and receiving immunomodulatory therapy. Particularly in these individuals, the clinical presentation of these infections may have atypical patterns, emphasizing the need to consider various diagnostic possibilities, including noninfectious conditions. Quick and accurate identification, along with prompt treatment, is crucial for improving patient outcomes. Therefore, understanding which pathogens are likely to cause infection based on factors such as timing post-transplantation, specific organ transplant, and the mechanism of action of immunomodulatory medications is essential. This review will provide a detailed description of the types of infections that may arise in the context of transplantation and immunomodulatory therapy.

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

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

Long-term survival from progressive multifocal leukoencephalopathy in living-donor liver transplant recipient with preformed donor-specific antibody

Intensive immunosuppression has enabled liver transplantation even in recipients with preformed donor-specific antibodies (DSA), an independent risk factor for graft rejection. However, these recipients may also be at high risk of progressive multifocal encephalopathy (PML) due to the comorbid immunosuppressed status. A 58-year-old woman presented with self-limited focal-to-bilateral tonic-clonic seizures 9 months after liver transplantation. She was desensitized using rituximab and plasma exchange before transplantation and was subsequently treated with steroids, tacrolimus, and everolimus after transplantation for her preformed DSA. Neurological examination revealed mild acalculia and agraphia. Cranial MRI showed asymmetric, cortex-sparing white matter lesions that increased over a week in the left frontal, left parietal, and right parieto-occipital lobes. Polymerase chain reaction (PCR) of the cerebrospinal fluid for the JC supported the diagnosis of PML. Immune reconstitution by reducing the immunosuppressant dose stopped lesion expansion, and PCR of the cerebrospinal fluid for the JC virus became negative. Graft rejection occurred 2 months after immune reconstitution, requiring readjustment of immunosuppressants. Forty-eight months after PML onset, the patient lived at home without disabling deficits. Intensive immunosuppression may predispose recipients to PML after liver transplantation with preformed DSA. Early immune reconstitution and careful monitoring of graft rejection may help improve outcomes.

Long-term prognosis and overall mortality in patients with progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is a rare but fatal opportunistic infection and mainly occurs in patients with immunosuppressive conditions. Despite the increasing number of patients receiving immunosuppressive treatments, studies on PML are still lacking due to its low prevalence and incidence. We retrospectively reviewed patients diagnosed with PML in two tertiary hospitals in South Korea from 1999 to 2021. Total of 47 PML patients were included. Of 27 patients (57.4%) were diagnosed with human immunodeficiency virus (HIV). Median last follow-up modified Rankin Scale (mRS) score was higher in the non-HIV PML group than that in the HIV group (5 vs. 4, p = 0.020). Median survival duration was lower in the non-HIV group (184 vs. 1,564 days). The 1-year and overall mortality rates of PML patients were significantly higher in the non-HIV group than that in HIV group (60.0% vs. 25.9%, p = 0.019; 80.0% vs. 40.7%, p = 0.007). Initial mRS score (HR 1.685, p = 0.038) and highly active antiretroviral therapy (HAART) in HIV patients (HR 0.374, p = 0.013) had a significant effect on overall mortality. Our findings suggest that early detection of PML with low mRS score and early initiation of HAART in patients with HIV may improve prognosis.

Cerebellar Progressive Multifocal Leukoencephalopathy Mimicking Anti-Yo-Antibody-Associated Rapidly Progressive Cerebellar Syndrome

A 58-year-old woman with a history of systemic lupus erythematosus (SLE) who was taking prednisolone and mycophenolate mofetil presented with gait disturbances that progressively worsened over a period of 3 months. Her blood test and cerebrospinal fluid (CSF) examination results did not indicate active SLE. Initial brain magnetic resonance imaging (MRI) revealed a small spotty lesion in the left cerebellar peduncle. The clinical course was consistent with rapidly progressive cerebellar syndrome (RPCS), which sometimes involves neuronal antibodies. The line blot assay detected anti-Yo antibodies, but no malignancy was found. Immunohistological techniques using rat brain sections yielded a negative result for anti-Yo antibodies. The second MRI revealed a focal lesion and surrounding spotty lesion in the left cerebellar peduncle, which was consistent with the punctate pattern observed in progressive multifocal leukoencephalopathy (PML). The CSF JCV-DNA test indicated the presence of cerebellar PML. Immunosuppressants were reduced, and mefloquine and mirtazapine were initiated. After approximately 2 years and 1 month, the CSF JCV-DNA results became negative. Cerebellar PML may exhibit a clinical course that is consistent with RPCS. The punctate pattern should be recognized as an early manifestation of PML. The CSF JCV-DNA copy number may serve as a useful indicator of PML stabilization.

An Elusive Target: Inhibitors of JC Polyomavirus Infection and Their Development as Therapeutics for the Treatment of Progressive Multifocal Leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is a rare demyelinating disease caused by infection with JC Polyomavirus (JCPyV). Despite the identification of the disease and isolation of the causative pathogen over fifty years ago, no antiviral treatments or prophylactic vaccines exist. Disease onset is usually associated with immunosuppression, and current treatment guidelines are limited to restoring immune function. This review summarizes the drugs and small molecules that have been shown to inhibit JCPyV infection and spread. Paying attention to historical developments in the field, we discuss key steps of the virus lifecycle and antivirals known to inhibit each event. We review current obstacles in PML drug discovery, including the difficulties associated with compound penetrance into the central nervous system. We also summarize recent findings in our laboratory regarding the potent anti-JCPyV activity of a novel compound that antagonizes the virus-induced signaling events necessary to establish a productive infection. Understanding the current panel of antiviral compounds will help center the field for future drug discovery efforts.

Successful treatment of HIV-associated progressive multifocal leukoencephalopathy (PML) with mirtazapine, mefloquine, and IVIG combination therapy: a case report

Progressive multifocal leukoencephalopathy (PML) is a severe demyelinating disease of the central nervous system caused by reactivation of the polyomavirus JC (JCV). Human immunodeficiency virus (HIV) infection is one of the leading causes of PML which has high morbidity and mortality due to the lack of a proven standard treatment. We found clinical and radiological improvement with the combination of high-dose methylprednisolone, mirtazapine, mefloquine, and IVIG in our patient who presented with neurological symptoms and had diagnosed concurrent acquired immunodeficiency syndrome (AIDS) and PML. To our knowledge, our case is the first HIV-associated PML which responded to this combination therapy.

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.

Progressive multifocal leukoencephalopathy, advanced ductal breast carcinoma, systemic sclerosis, and checkpoint inhibitors: a therapeutic dilemma

Progressive multifocal leukoencephalopathy (PML) is a demyelinating central nervous system disease infection by JC virus (JCV) in patients with a significant decline in cellular immunity. No specific treatment has demonstrated efficacy, and the disease progresses to death in most patients. Recent findings have shown stabilization or improvement of PML lesions after treatment with checkpoint inhibitors (CPI) based on immune reconstitution. Nevertheless, immunotherapy may specifically cause autoimmune diseases or may deteriorate pre-existing ones. We report a case of a patient under treatment for advanced ductal breast carcinoma and systemic sclerosis, who developed PML. The therapeutic approach included withdrawal of drugs with possible immunosuppressive effect and treatment with pembrolizumab. In the absence of reliable markers to predict CPIs response and a concern for an autoimmune worsening, immunotherapy was administered late in the course of the disease. Finally, she did not experience an autoimmune disease flare-up; however, pembrolizumab could not prevent disease progression. We believe that potential autoimmune complications should not delay treatment initiation with CPIs in PML.

Progressive multifocal leukoencephalopathy associated with chemotherapy induced lymphocytopenia in solid tumors – case report of an underestimated complication

Background

JC virus reactivation causing progressive multifocal leukoencephalopathy (PML) occurs preferentially in human immunodeficiency virus (HIV) positive individuals or patients suffering from hematologic neoplasms due to impaired viral control. Reactivation in patients suffering from solid malignancies is rarely described in published literature.

Case Presentation

Here we describe a case of PML in a male patient suffering from esophageal cancer who underwent neoadjuvant radiochemotherapy and surgical resection in curative intent resulting in complete tumor remission. The radiochemotherapy regimen contained carboplatin and paclitaxel (CROSS protocol). Since therapy onset, the patient presented with persistent and progredient leukopenia and lymphopenia in absence of otherwise known risk factors for PML. Symptom onset, which comprised aphasia, word finding disorder, and paresis, was apparent 7 months after therapy initiation. There was no relief in symptoms despite standard of care PML directed supportive therapy. The patient died two months after therapy onset.

Conclusion

PML is a very rare event in solid tumors without obvious states of immununosuppression and thus harbors the risk of unawareness. The reported patient suffered from lymphopenia, associated with systemic therapy, but was an otherwise immunocompetent individual. In case of neurologic impairment in patients suffering from leukopenia, PML must be considered – even in the absence of hematologic neoplasia or HIV infection.

The risk of infections for multiple sclerosis and neuromyelitis optica spectrum disorder disease-modifying treatments: Eighth European Committee for Treatment and Research in Multiple Sclerosis Focused Workshop Review. April 2021

Over the recent years, the treatment of multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) has evolved very rapidly and a large number of disease-modifying treatments (DMTs) are now available. However, most DMTs are associated with adverse events, the most frequent of which being infections. Consideration of all DMT-associated risks facilitates development of risk mitigation strategies. An international focused workshop with expert-led discussions was sponsored by the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) and was held in April 2021 to review our current knowledge about the risk of infections associated with the use of DMTs for people with MS and NMOSD and corresponding risk mitigation strategies. The workshop addressed DMT-associated infections in specific populations, such as children and pregnant women with MS, or people with MS who have other comorbidities or live in regions with an exceptionally high infection burden. Finally, we reviewed the topic of DMT-associated infectious risks in the context of the current SARS-CoV-2 pandemic. Herein, we summarize available evidence and identify gaps in knowledge which justify further research.

A Case of Progressive Multifocal Leukoencephalopathy in a Fumaric Acid-Treated Psoriasis Patient With Severe Lymphopenia Among Other Risk Factors

Progressive multifocal leukoencephalopathy (PML) is a potentially fatal condition caused by a brain infection with JC polyomavirus (JCV), which occurs almost exclusively in immunocompromised patients. Modern immunosuppressive and immunomodulatory treatments for cancers and autoimmune diseases have been accompanied by increasing numbers of PML cases. We report a psoriasis patient treated with fumaric acid esters (FAEs) with concomitant hypopharyngeal carcinoma and chronic alcohol abuse who developed PML. Grade 4 lymphopenia at the time point of PML diagnosis suggested an immunocompromised state. This case underscores the importance of immune cell monitoring in patients treated with FAEs, even more so in the presence of additional risk factors for an immune dysfunction.

Innovative therapeutic concepts of progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is an opportunistic viral disease of the brain-caused by human polyomavirus 2. It affects patients whose immune system is compromised by a corresponding underlying disease or by drugs. Patients with an underlying lymphoproliferative disease have the worst prognosis with a mortality rate of up to 90%. Several therapeutic strategies have been proposed but failed to show any benefit so far. Therefore, the primary therapeutic strategy aims to reconstitute the impaired immune system to generate an effective endogenous antiviral response. Recently, anti-PD-1 antibodies and application of allogeneic virus-specific T cells demonstrated promising effects on the outcome in individual PML patients. This article aims to provide a detailed overview of the literature with a focus on these two treatment approaches.

Pembrolizumab treatment of inflammatory progressive multifocal leukoencephalopathy: a report of two cases

Progressive multifocal leukoencephalopathy (PML) is a rare but devastating neurological disease caused by reactivation of the JC virus in susceptible individuals. The illness has classically been associated with the human immunodeficiency virus (HIV) and multiple sclerosis (MS) patients who are treated with natalizumab. It is also associated with haematological malignancies, organ transplantation, autoimmune disease and immunodeficiency. Aside from natalizumab, a range of other immunomodulators including obinutuzumab and rituximab have been associated with PML. The nature of these associations is unclear due to the overall low incidence of PML associated with these drugs and the fact that most patients will have other confounding risk factors for developing the disease. There is no known effective treatment available for PML in the non-HIV, non-MS cohort. Recent case studies and series have proposed that pembrolizumab, an anti-PD-1 immune checkpoint inhibitor, may be a potentially efficacious option for these patients. We present two cases of non-HIV, non-MS patients with PML who were treated with pembrolizumab with little clinical benefit. The literature surrounding pembrolizumab use in PML is discussed, with a focus on potential indicators of successful outcomes for patients who receive this therapy.

Progressive multifocal leukoencephalopathy in an immunocompetent patient: A case report and review of literature

Progressive multifocal leukoencephalopathy (PML), a demyelinating disease of the brain, caused by the John Cunningham virus (JCV) is usually seen in patients who are immunocompromised. Here, we describe a case of an immunocompetent patient diagnosed with PML and a comprehensive literature review. A 64-year-old Caucasian male presented with acute worsening of progressive neurological decline with difficulty in vision and reading. Based on history, examination, cerebrospinal fluid markers, histopathology, and magnetic resonance imaging brain at the time of presentation diagnosed the patient with PML in a setting of no immunosuppression disorder. The patient was started on Pelfilgrastim with significant systematic improvement. In our literature review, it was seen that the average age of symptom presentation was 57.5 with predominance in males. Most of the patients presented with progressive neurological deficits with symptomology ranging from mild confusion, aphasia, anxiety to sensory disturbances with numbness, hemiparesis, and hemianopsia. Out of the 21 cases, patients responded to mirtazapine and intravenous pulse methylprednisolone (IVMP). The mortality rate was close to 50% with 11 fatal cases and 10 nonfatal cases. Our case and literature review demonstrate the possibility that PML may very rarely occur in patients that are immunocompetent. Furthermore, our review showed that patients responded well to mirtazapine and IVMP. We also want to highlight that the mortality rate was lower in this review and was only compared to mortality in PML associated with immunocompromised status.

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.

Juxtacortical susceptibility changes in progressive multifocal leukoencephalopathy at the gray-white matter junction correlates with iron-enriched macrophages

OBJECTIVE

Describe magnetic resonance imaging (MRI) susceptibility changes in progressive multifocal leukoencephalopathy (PML) and identify neuropathological correlates.

METHODS

PML cases and matched controls with primary central nervous system lymphoma (PCNSL) were retrospectively identified. MRI brain at 3 T and 7 T were reviewed. MRI-pathology correlations in fixed brain autopsy tissue were conducted in three subjects with confirmed PML.

RESULTS

With PML (n = 26 total, n = 5 multiple sclerosis natalizumab-associated), juxtacortical changes on susceptibility-weighted imaging (SWI) or gradient echo (GRE) sequences were noted in 3/3 cases on 7 T MRI and 14/22 cases (63.6%) on 1.5 T or 8/22 (36.4%) 3 T MRI. Similar findings were only noted in 3/25 (12.0%) of PCNSL patients (odds ratio (OR) 12.83, 95% confidence interval (CI), 2.9-56.7, p < 0.001) on 1.5 or 3 T MRI. On susceptibility sequences available prior to diagnosis of PML, 7 (87.5%) had changes present on average 2.7 ± 1.8 months (mean ± SD) prior to diagnosis. Postmortem 7 T MRI showed SWI changes corresponded to areas of increased iron density along the gray-white matter (GM-WM) junction predominantly in macrophages.

CONCLUSION

Susceptibility changes in PML along the GM-WM junction can precede noticeable fluid-attenuated inversion recovery (FLAIR) changes and correlates with iron accumulation in macrophages.

The neuroradiology of progressive multifocal leukoencephalopathy: a clinical trial perspective

Progressive multifocal leukoencephalopathy (PML) is an opportunistic infection of the central nervous system caused by the JC virus, which infects white and grey matter cells and leads to irreversible demyelination and neuroaxonal damage. Brain magnetic resonance imaging (MRI), in addition to the clinical presentation and demonstration of JC virus DNA either in the CSF or by histopathology, is an important tool in the detection of PML. In clinical practice, standard MRI pulse sequences are utilized for screening, diagnosis, and monitoring of PML, but validated imaging-based outcome measures for use in prospective, interventional clinical trials for PML have yet to be established. We review the existing literature regarding the use of MRI and positron emission tomography imaging in PML and discuss the implications of PML histopathology for neuroradiology. MRI not only demonstrates the localization and extent of PML lesions, but also mirrors the tissue destruction, ongoing viral spread, and resulting inflammation. Finally, we explore the potential for imaging measures to serve as an outcome in PML clinical trials and provide recommendations for current and future imaging outcome measure development in this area.

Off the Shelf Third Party Virus Specific T-Cell Therapy to Treat JC Polyomavirus Infection in Hematopoietic Stem Cell Transplant Recipients

BACKGROUND

Progressive multifocal leukoencephalopathy (PML) is a progressive and generally fatal demyelinating neurological disease that occurs in profoundly immunocompromised patients due to infection with the human polyomavirus JC virus (JCPyV). Treatment options are limited and are largely focused on restoring T-cell immunity and outcomes are historically poor. Control of JCPyV in the setting of an immunocompromised patient by adoptive transfer of third-party virus specific T-cells (VSTs) has been described in a small number of cases.

OBJECTIVE

To investigate treatment response and outcomes in recipients of hematopoietic stem cell transplant (HSCT) with PML treated with third-party VSTs directed against BK virus, a highly homologous polyoma virus that shares immunogenic epitopes with JCPyV.

STUDY DESIGN

Retrospective chart review was performed on four patients who received VSTs for the treatment of PML at Cincinnati Children's Hospital Medical Center since 2019 RESULTS: VSTs were safely administered with no cases of graft-vs-host disease and no infusion reactions. One patient, who was treated almost immediately after diagnosis, was able to clear JCPyV from blood and CSF with resultant stabilization of neurologic decline. Interferon-gamma ELISpot demonstrated virus specific T-cells in the peripheral blood following infusion. Response was maintained through repeat infusions. Three other patients, all of whom had a longer delay between diagnosis and infusion, had progressive neurologic decline despite varying degree of improvement in viral load.

CONCLUSION

PML is a rare but often fatal complication following HSCT for which few treatment options are available. BK directed, JCPyV cross-reactive VSTs are a safe and viable therapeutic option and prompt administration should be considered after a diagnosis of PML is made. Key points • Virus specific T cells targeting JCPyV virus are safe with no infusional toxicity or de-novo graft versus host disease. • Virus specific T-cells have evidence of efficacy in some cases of PML, but further studies are needed to determine factors that will optimize response.

Progressive multifocal leukoencephalopathy successfully treated with mefloquine and literature review

Progressive multifocal leukoencephalopathy (PML) is an opportunistic infection due to reactivation of John Cunningham virus (JCV). The diagnosis depends on evidence from clinical, imaging, and virologic studies. When the cerebrospinal fluid shows a negative polymerase chain reaction result, brain biopsy is required to confirm the diagnosis. PML has no standard treatment except for immune reconstitution. The anti-JCV effect of mefloquine, however, is supported by some studies, and if brain biopsy is difficult, a mefloquine trial can be considered. We describe a case of possible PML successfully treated with mefloquine.

Cerebellar progressive multifocal leukoencephalopathy associated with pulmonary sarcoidosis

Progressive multifocal leukoencephalopathy can complicate the course of a patient with sarcoidosis. Here we present a rare case of a 35-year-old patient with pulmonary sarcoidosis whose course was complicated by progressive multifocal leukoencephalopathy involving the cerebellum. Neuroimaging and cerebrospinal fluid PCR played a crucial role in the diagnosis.

Advances in Treatment of Progressive Multifocal Leukoencephalopathy

Progressive multifocal encephalopathy (PML) is a severe demyelinating disease of the central nervous system (CNS) caused by JC virus (JCV), which occurs in immunocompromised individuals. Management of PML relies on restoration of immunity within the CNS. However, when this restoration cannot be readily achieved, PML has a grim prognosis. Innovative strategies have shown promise in promoting anti‐JCV immune responses, and include T‐cell adoptive transfer or immune checkpoint inhibitor therapies. Conversely, management of immune reconstitution inflammatory syndrome, particularly in iatrogenic PML, remains a major challenge. In this paper, we review recent development in the treatment of PML. ANN NEUROL 2021;90:865–873

Progressive multifocal leukoencephalopathy in systemic lupus erythematosus managed with pembrolizumab: A case report with literature review

Progressive multifocal leukoencephalopathy (PML) is one of the rare but lethal infectious complication in patients with SLE, manifesting progressive central nervous demyelination caused by JC virus (JCV). There have been no effective antiviral agents so far; however, immune checkpoint inhibitors (ICI) have been demonstrated as potential treatments by reinvigorating antiviral T-cell activity against JC virus. To date, sixteen PML cases treated with anti-PD-1 have been reported; however, there was no report addressing the use of ICI in patients with concomitant PML and rheumatic disease, possibly due to the concern for possible autoimmune disease flare-up. In addition, treatment outcomes of these ICI-treated cases were heterogeneous. Experiences from these cases suggested that high disease burden, JC viral load in CSF, and severe immunosuppression status at baseline may predict poor response to treatment. Our case, a 62-year-old woman with long-standing SLE, turned out to have a delayed but effective response to prolonged ICI treatment despite of her high JC viral load and immunosuppressed status caused by high-dose steroid and rituximab. To our knowledge, this is the first case report with SLE complicated with PML clinically improved by pembrolizumab treatment without consequent immune related adverse events (irAE). Considering the lethal nature of PML and absence of effective medication, ICI is a reasonable consideration in patients with SLE and progressive PML.

Antivirals against human polyomaviruses: Leaving no stone unturned

Human polyomaviruses (HPyVs) encompass more than 10 species infecting 30%-90% of the human population without significant illness. Proven HPyV diseases with documented histopathology affect primarily immunocompromised hosts with manifestations in brain, skin and renourinary tract such as polyomavirus-associated nephropathy (PyVAN), polyomavirus-associated haemorrhagic cystitis (PyVHC), polyomavirus-associated urothelial cancer (PyVUC), progressive multifocal leukoencephalopathy (PML), Merkel cell carcinoma (MCC), Trichodysplasia spinulosa (TS) and pruritic hyperproliferative keratinopathy. Although virus-specific immune control is the eventual goal of therapy and lasting cure, antiviral treatments are urgently needed in order to reduce or prevent HPyV diseases and thereby bridging the time needed to establish virus-specific immunity. However, the small dsDNA genome of only 5 kb of the non-enveloped HPyVs only encodes 5-7 viral proteins. Thus, HPyV replication relies heavily on host cell factors, thereby limiting both, number and type of specific virus-encoded antiviral targets. Lack of cost-effective high-throughput screening systems and relevant small animal models complicates the preclinical development. Current clinical studies are limited by small case numbers, poorly efficacious compounds and absence of proper randomized trial design. Here, we review preclinical and clinical studies that evaluated small molecules with presumed antiviral activity against HPyVs and provide an outlook regarding potential new antiviral strategies.

From hydroxychloroquine to ivermectin: what are the anti-viral properties of anti-parasitic drugs to combat SARS-CoV-2?

BACKGROUND

Nearly a year into the COVID-19 pandemic, we still lack effective anti-SARS-CoV-2 drugs with substantial impact on mortality rates except for dexamethasone. As the search for effective antiviral agents continues, we aimed to review data on the potential of repurposing antiparasitic drugs against viruses in general, with an emphasis on coronaviruses.

METHODS

We performed a review by screening in vitro and in vivo studies that assessed the antiviral activity of several antiparasitic agents: chloroquine, hydroxychloroquine (HCQ), mefloquine, artemisinins, ivermectin, nitazoxanide (NTZ), niclosamide, atovaquone and albendazole.

RESULTS

For HCQ and chloroquine we found ample in vitro evidence of antiviral activity. Cohort studies that assessed the use of HCQ for COVID-19 reported conflicting results, but randomized controlled trials (RCTs) demonstrated no effect on mortality rates and no substantial clinical benefits of HCQ used either for prevention or treatment of COVID-19. We found two clinical studies of artemisinins and two studies of NTZ for treatment of viruses other than COVID-19, all of which showed mixed results. Ivermectin was evaluated in one RCT and few observational studies, demonstrating conflicting results. As the level of evidence of these data is low, the efficacy of ivermectin against COVID-19 remains to be proven. For chloroquine, HCQ, mefloquine, artemisinins, ivermectin, NTZ and niclosamide, we found in vitro studies showing some effects against a wide array of viruses. We found no relevant studies for atovaquone and albendazole.

CONCLUSIONS

As the search for an effective drug active against SARS-CoV-2 continues, we argue that pre-clinical research of possible antiviral effects of compounds that could have antiviral activity should be conducted. Clinical studies should be conducted when sufficient in vitro evidence exists, and drugs should be introduced into widespread clinical use only after being rigorously tested in RCTs. Such a search may prove beneficial in this pandemic or in outbreaks yet to come.

JC Polyomavirus and Transplantation: Implications for Virus Reactivation after Immunosuppression in Transplant Patients and the Occurrence of PML Disease

The JC polyomavirus (JCPyV/JCV) is a member of the Polyomaviridae family and is ubiquitious in the general population, infecting 50–80% of individuals globally. A primary infection with JCV usally results in an asymptomatic, persistent infection that establishes latency in the renourinary tract. Reactivation from latency via iatrogenic immununosuppression for allograft transplantation may result in organ pathology and a potential life-threatening neuropathological disease in the form of progressive multifocal leukoencephalopathy (PML). Currently, no treatment exists for PML, a rare complication that occurs after transplantation, with an incidence of 1.24 per 1000 persons a year among solid organ transplant patients. PML is also observed in HIV patients who are immununosuppressed and are not receiving antiretroviral therapy, as well as individuals treated with biologics to suppress chronic inflammatory responses due to multiple sclerosis, Crohn’s disease, non-Hodgkin’s lymphoma, rheumatoid arthritis, and other autoimmune-mediated hematological disorders. Here, we describe the proposed mechanisms of JCV reactivation as it relates to iatrogenic immunosuppression for graft survival and the treatment of proinflammatory disease, such as biologics, proposed trafficking of JCV from the renourinary tract, JCV central nervous system dissemination and the pathology of PML in immunosuppressed patients, and potential novel therapeutics for PML disease.

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.

Long-Term Survival after Progressive Multifocal Leukoencephalopathy in a Patient with Primary Immune Deficiency and NFKB1 Mutation

PURPOSE

To describe the development of progressive multifocal leukoencephalopathy (PML) in a patient with primary immune deficiency (PID) due to a NFKB1 (nuclear factor kB subunit 1) mutation, who was treated successfully with a combination of mirtazapine and mefloquine.

METHODS

We've based the treatment of our patient on literature research and provide a review of PML in CVID patients.

RESULTS

Only a few reports have been published on the occurrence of PML in PID. PML is mainly observed in patients with reduced cellular immunity, which was not the case in our patient. Successful treatment options in this population are limited. Though severely disabled, our patient still survives, more than 4 years after symptom onset and shows consistent improvement on MRI (magnetic resonance imaging) and CSF (cerebrospinal fluid) analysis.

CONCLUSION

We conclude that some patients with PML might be treatable and can show long-term survival although neurological deficits remain. Involvement of humoral immunity in the pathogenesis of PML as well as the possible role of NFKB1 mutations in response to specific pathogens deserves further investigation.

JC Polyomavirus, progressive multifocal leukoencephalopathy and immune reconstitution inflammatory syndrome: a review

The human neurotropic virus JC Polyomavirus, a member of the Polyomaviridae family, is the opportunistic infectious agent causing progressive multifocal leukoencephalopathy, typically in immunocompromised individuals. The spectrum of underlying reasons for the systemic immunosuppression that permits JCV infection in the central nervous system has evolved over the past 2 decades, and therapeutic immunosuppression arousing JCV infection in the brain has become increasingly prominent as a trigger for PML. Effective immune restoration subsequent to human immunodeficiency virus-related suppression is now recognized as a cause for unexpected deterioration of symptoms in patients with PML, secondary to a rebound inflammatory phenomenon called immune reconstitution inflammatory syndrome, resulting in significantly increased morbidity and mortality in a disease already infamous for its lethality. This review addresses current knowledge regarding JC Polyomavirus, progressive multifocal leukoencephalopathy, progressive multifocal leukoencephalopathy-related immune reconstitution inflammatory syndrome, and the immunocompromised states that incite JC Polyomavirus central nervous system infection, and discusses prospects for the future management of these conditions.

Treatment of Progressive Multifocal Leukoencephalopathy Using Immune Restoration

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

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.

The Use of Antimalarial Drugs against Viral Infection

In recent decades, drugs used to treat malaria infection have been shown to be beneficial for many other diseases, including viral infections. In particular, they have received special attention due to the lack of effective antiviral drugs against new emerging viruses (i.e., HIV, dengue virus, chikungunya virus, Ebola virus, etc.) or against classic infections due to drug-resistant viral strains (i.e., human cytomegalovirus). Here, we reviewed the in vitro/in vivo and clinical studies conducted to evaluate the antiviral activities of four classes of antimalarial drugs: Artemisinin derivatives, aryl-aminoalcohols, aminoquinolines, and antimicrobial drugs.

Association of Progressive Multifocal Leukoencephalopathy Lesion Volume With JC Virus Polymerase Chain Reaction Results in Cerebrospinal Fluid of Natalizumab-Treated Patients With Multiple Sclerosis

Importance

The JC virus (JCV) was named after the first patient to be described with progressive multifocal leukoencephalopathy (PML), John Cunningham. Detection of JC virus DNA in cerebrospinal fluid (CSF) by polymerase chain reaction (PCR), and of specific lesions by brain magnetic resonance imaging (MRI), are both considered essential for the diagnosis of natalizumab-associated PML (NTZ-PML) in patients with multiple sclerosis. However, strict pharmacovigilance by MRI can result in detection of patients with small lesions and undetectable JCV DNA in CSF.

Objective

To investigate the association of PML lesion characteristics on MRI with both qualitative and quantitative JCV PCR results in CSF of patients with NTZ-PML.

Design, Setting and Participants

This was a retrospective, cross-sectional study conducted from January 2007 to December 2014 in patients considered to have NTZ-PML based on a set of predefined criteria. Follow-up was at least 6 months. Data of patients from the Dutch-Belgian NTZ-PML cohort and patients treated at multiple medical centers in Belgium and the Netherlands and selected for research purposes were included as a convenience sample.

Main Outcomes and Measures

Brain MRI scans were analyzed for PML lesion volume, location, dissemination, and signs of inflammation. Associations of the qualitative and quantitative CSF JCV PCR results with PML MRI characteristics were calculated.

Results

Of the 73 patients screened, 56 were included (37 were women). At inclusion, 9 patients (16.1%) had undetectable JCV DNA in CSF. Patients with a positive PCR had larger total PML lesion volumes than those with undetectable JCV DNA (median volume, 22.9 mL; interquartile range, 9.2-60.4 mL vs median volume, 6.7 mL; interquartile range, 4.9-14.7 mL; P = .008), and logistic regression showed that a lower PML lesion volume significantly increased the probability for undetectable JCV DNA. There was a positive correlation between PML lesion volume and JCV copy numbers (Spearman ρ, 0.32; P = .03). Progressive multifocal leukoencephalopathy lesion volume was higher in patients with PML symptoms and in patients with more widespread lesion dissemination. No association was found between PCR results and PML lesion dissemination, signs of inflammation, or PML symptoms.

Conclusions and Relevance

Smaller NTZ-PML lesions are associated with a higher likelihood of undetectable JCV DNA in CSF. This may preclude a formal diagnosis of PML and can complicate patient treatment in patients with small MRI lesions highly suggestive of PML detected early through pharmacovigilance.

Not a Disease of the Past: A Case Series of Progressive Multifocal Leukoencephalopathy in the Established Antiretroviral Era

Progressive multifocal leukoencephalopathy (PML) and PML immune reconstitution inflammatory syndrome (PML-IRIS) can be devastating neurological processes associated with HIV, but limited knowledge of their characteristics in the established antiretroviral therapy (ART) era is available. We conducted a case series to evaluate the clinical course of PML and PML-IRIS at our urban safety-net hospital in Atlanta, GA. All HIV-positive individuals with a positive John Cunningham virus DNA polymerase chain reaction in the spinal fluid between May 1, 2013 to June 1, 2017 were identified from the electronic health records (EHRs) using the HIV Disease Registry. Demographics, symptom presentation, laboratory data, imaging results, treatment, and outcomes were abstracted from the EHR. PML and PML-IRIS were defined using the American Association of Neurology criteria. Of the 32 individuals identified, 6 (19%) were felt to have asymptomatic positive results. Of the remainder, 15 (58%) HIV-positive patients had PML and 11 (42%) PML-IRIS (2 with an unmasking presentation and 9 with a paradoxical presentation). The most common presenting symptoms were motor weakness (18, 69%), cognitive deficits (15, 58%), and dysarthria (11, 42%). Corticosteroids were used in 12 patients and maraviroc in 3 patients. Outcomes were dismal with 7 (47%) patients with PML and 9 (82%) with PML-IRIS dying or being referred to hospice, with median survival times of 266 days in the PML group and 109 days in the PML-IRIS group. Despite widespread access to ART, patients with PML continue to have poor outcomes, particularly among those who develop PML-IRIS. More research is needed to understand the risks for and prevention of PML-IRIS.

Slowly progressive fatal PML-IRIS following antiretroviral initiation at CD4+ nadir of 350 cells/mm3 despite CD4+ cell count rise to 900 cells/mm3

AIDS-related progressive multifocal leukoencephalopathy (PML)-immune reconstitution inflammatory syndrome (IRIS) is a central nervous system inflammatory syndrome where immune response to John Cunningham (JC) virus antigen following antiretroviral therapy (ART) causes breakdown of the blood–brain barrier. We report a unique case of PML-IRIS, which presented with dystonic choreoathetosis after initiation of ART at a CD4+ cell count of 350 cells/mm3. This report shows continuous progression of the disease over a period of two years, despite robust immune reconstitution. The worsening of neurological symptoms, persistent positivity of JC virus in CSF, and progressive inflammatory picture on MR scans in the setting of a CD4+ cell count of 900 cells/mm3 highlight a different variant of PML-IRIS, and challenge the role of CD4+ cell count in diagnosing opportunistic infections in HIV/AIDS patients.

Pembrolizumab Treatment for Progressive Multifocal Leukoencephalopathy

BACKGROUND

Progressive multifocal leukoencephalopathy (PML) is an opportunistic brain infection that is caused by the JC virus and is typically fatal unless immune function can be restored. Programmed cell death protein 1 (PD-1) is a negative regulator of the immune response that may contribute to impaired viral clearance. Whether PD-1 blockade with pembrolizumab could reinvigorate anti-JC virus immune activity in patients with PML was unknown.

METHODS

We administered pembrolizumab at a dose of 2 mg per kilogram of body weight every 4 to 6 weeks to eight adults with PML, each with a different underlying predisposing condition. Each patient received at least one dose but no more than three doses.

RESULTS

Pembrolizumab induced down-regulation of PD-1 expression on lymphocytes in peripheral blood and in cerebrospinal fluid (CSF) in all eight patients. Five patients had clinical improvement or stabilization of PML accompanied by a reduction in the JC viral load in the CSF and an increase in in vitro CD4+ and CD8+ anti-JC virus activity. In the other three patients, no meaningful change was observed in the viral load or in the magnitude of antiviral cellular immune response, and there was no clinical improvement.

CONCLUSIONS

Our findings are consistent with the hypothesis that in some patients with PML, pembrolizumab reduces JC viral load and increases CD4+ and CD8+ activity against the JC virus; clinical improvement or stabilization occurred in five of the eight patients who received pembrolizumab. Further study of immune checkpoint inhibitors in the treatment of PML is warranted. (Funded by the National Institutes of Health.).

Treatment of natalizumab-associated PML with filgrastim

Objective

There is no consensus on the treatment of progressive multifocal leukoencephalopathy (PML) occurring in multiple sclerosis (MS) patients treated with natalizumab (Nz). We report novel immune activating treatment with filgrastim of Nz‐associated PML in MS patients treated at Rush University Medical Center.

Methods

We retrospectively analyzed 17 Nz‐PML patients treated at this single tertiary referral center between 2010 and 2017. We reviewed the clinical symptoms, diagnostic methods, survival, outcome and MS modifying therapy (MSMT) after Nz‐PML.

Results

PML occurred after an average of 49 Nz infusions. To facilitate JCV elimination by accelerating immune reconstitution inflammatory syndrome (IRIS), all patients received subcutaneous filgrastim upon PML diagnosis and discontinuation of Nz; eight received plasma exchange (PLEX). Earlier than previously published, PML‐IRIS occurred in 15 of 17 (88.2%) patients within a mean of 57.4 days (SD 21.20) after the last Nz infusion. Seven patients recovered to or near baseline. There were no PML/IRIS–related fatalities but one patient committed suicide 2.5 years later. PLEX had no impact on PML outcome. Of 17 patients, 3 (18%) had MS relapses within 1 year after PML, and 5 (29%) beyond 1 year of PML onset, which is lower than expected in highly active MS patients. Eight patients started MSMTs after Nz‐PML on an average of 26 months after Nz withdrawal.

Interpretation

Our findings indicate that immunoactivation with filgrastim during PML and careful management of subsequent IRIS is likely beneficial in patients with Nz‐PML, without worsening MS. The clinical course of MS may be ameliorated by PML.

The spectrum of progressive multifocal leukoencephalopathy: a practical approach

John Cunningham virus (JCV) infection of the central nervous system causes progressive multifocal leukoencephalopathy (PML) in patients with systemic immunosuppression. With the increased application of modern immunotherapy and biologics in various immune-mediated disorders, the PML risk spectrum has changed. Thus, new tools and strategies for risk assessment and stratification in drug-associated PML such as the JCV antibody indices have been introduced. Imaging studies have highlighted atypical presentations of cerebral JCV disease such as granule cell neuronopathy. Imaging markers have been developed to differentiate PML from new multiple sclerosis lesions and to facilitate the early identification of pre-clinical manifestations of PML and its immune reconstitution inflammatory syndrome. PML can be diagnosed either by brain biopsy or by clinical, radiographic and virological criteria. Experimental treatment options including immunization and modulation of interleukin-mediated immune response are emerging. PML should be considered in any patient with compromised systemic or central nervous system immune surveillance presenting with progressive neurological symptoms.

Progressive Multifocal Leukoencephalopathy in the Absence of Typical Radiological Changes: Can We Make a Diagnosis?

Patient: Female, 32

Final Diagnosis: Progressive multifocal leukoencephalopathy

Symptoms: Progressive behavioral changes • seizures

Medication: —

Clinical Procedure: Management

Specialty: Neurology

Remarkable improvement in progressive multifocal leukoencephalopathy following acute pyelonephritis with bacteremia

Progressive multifocal leukoencephalopathy (PML) is caused by John Cunningham (JC) virus in immunocompromized patients such as those with human immunodeficiency virus (HIV) infection, hematological malignancy, autoimmune disorder, and immunodeficiency disorder as well as those undergoing chemotherapy or immunosuppressive therapy. No effective treatments have been established for PML, which commonly causes severe neurological sequelae. We describe the first case of PML in a patient without HIV infection who exhibited remarkable improvement following acute pyelonephritis with Escherichia coli bacteremia.

A controlled inflammation and a regulatory immune system are associated with more favorable prognosis of progressive multifocal leukoencephalopathy

OBJECTIVE

In the present study, we analyzed the inflammatory profiles of brain tissues obtained from patients with progressive multifocal leukoencephalopathy (PML) due to John Cunningham (JC) virus infection to identify potential prognostic factors.

METHODS

The study included seven patients (two men, five women) who had been pathologically diagnosed with PML, and all of whom were HIV negative. Fixed brain samples were analyzed via hematoxylin and eosin (HE) staining and Klüver-Barrera (KB) staining. We then performed immunohistochemistry (IHC) specific to JC virus capsid proteins (VP1 and VP2/3) and lymphocyte surface markers (CD4, CD8, CD138, and PD-1).

RESULTS

The mean age at onset was 53.4, while the mean duration until biopsy/autopsy was 4.7 months. Four patients were included in the good prognosis (GP) group, while three were included in the poor prognosis (PP) group. Pathological analysis revealed a significantly larger number of CD4-positive T-cell infiltrations (P = .029) in the GP group, along with a preserved CD4:CD8 ratio. Larger numbers of CD138-positive plasma cells were also observed in the GP group (P = .029) than in the PP group. Linear regression analyses revealed a significant association between the numbers of CD138-positive plasma cells and PD-1-positive cells (R² = 0.80).

CONCLUSIONS

Viral loads in the cerebrospinal fluid, a controlled inflammatory response mediated by CD4- and CD8-positive T cells, and plasma cells are associated with PML prognosis. Our findings further indicate that regulatory plasma cells may regulate inflammatory T-cell activity via a PD-1/PD-L1 immuno-checkpoint pathway, thereby protecting the uninfected brain from excessive immune-mediated damage during an active JC virus infection.