Progressive multifocal leukoencephalopathy

B-cell Depletion Therapy in Pediatric Neuroinflammatory Disease

PURPOSE OF REVIEW

B-cell depletion therapy, including anti-CD20 and anti-CD19 therapies, is increasingly used for a variety of autoimmune and conditions, including those affecting the central nervous system. However, B-cell depletion therapy use can be complicated by adverse effects associated with administration and immunosuppression. This review aims to summarize the application of anti-CD20 and anti-CD19 therapies for the pediatric neurologist and neuroimmunologist.

RECENT FINDINGS

Most existing literature come from clinical trials with adult patients, although more recent studies are now capturing the effects of these therapies in children. The most common side effects include infusion related reactions and increased infection risk from immunosuppression. Several strategies can mitigate infusion related reactions. Increased infections due to persistent hypogammaglobulinemia can benefit from replacement immunoglobulin. B-cell depletion therapies can be safe and effective in pediatric patients. Anticipation and mitigation of common adverse effects through primary prevention strategies, close monitoring, and appropriate symptomatic management can improve safety and tolerability.

A rare case of progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is a rare demyelinating disease of the central nervous system (CNS) due to John Cunningham (JC) virus reactivation most often in immunocompromised patients. The brainstem and the anterior corpus callosum are uncommon locations for white matter lesions. We present a case of PML in a 40-year-old female presenting to the emergency department for a tonic seizure with transient postictal confusion. The inpatient workup revealed low cluster of differentiation cell counts (CD3 and CD4), transaminitis, positive drug screen, and abnormal electroencephalogram (EEG). The computed tomogram (CT) of the head and magnetic resonance image (MRI or MR) of the brain showed evidence of subcortical and periventricular white matter lesions in the right hemisphere extending into the brainstem and the left frontal lobe. The hospital course consisted of supportive measures, seizure treatment along with prophylaxis, and human immunodeficiency virus (HIV) management along with prophylactic antibiotics. The patient was discharged with appropriate medications and outpatient referrals. Overall, this case describes some key points. It highlights particular imaging characteristics of PML in the setting of inadequately treated HIV. For example, white matter lesions cross the anterior corpus callosum rather than the splenium, as in the "barbell" sign. In addition, the lesions extend inferiorly along the ipsilateral corticospinal tract into the midbrain and pons. This could be one of the first cases to capture both of these features given the rarity of their concomitant occurrence.

Progressive multifocal leukoencephalopathy and spectrum of predisposing conditions: a 20-year retrospective cohort study in a tertiary center in São Paulo, Brazil

BACKGROUND

Epidemiological studies on predisposing conditions and outcomes of progressive multifocal leukoencephalopathy (PML) cases have been carried out exclusively in high-income countries. We aim to report and compare the main characteristics and outcomes of patients with PML and several underlying diseases in a referral center in a middle-income country.

METHODS

We performed a retrospective cohort study of PML cases admitted to a tertiary care hospital in São Paulo, Brazil during 2000-2022. Demographic and PML-specific variables were recorded. One-year case-fatality rate and factors associated with death were identified using a multivariate Cox proportional hazards regression model.

RESULTS

Ninety-nine patients with PML were included. HIV infection (84.8%) and malignancy (14.1%) were the most prevalent underlying conditions. Other predisposing diseases were autoimmune/inflammatory diseases (5.1%) and solid organ transplantation (1.0%). One (1.0%) patient had liver cirrhosis and another (1.0%) patient was previously healthy. Focal motor deficits (64.2%) and gait instability (55.1%) were the most common signs. The one-year case-fatality rate was 52.5% (95% CI 42.2-62.7). The one-year case-fatality rate (95% CI) in patients with or without malignancy (85.7%, 95% CI 57.2-98.2% and 47.1%, 95% CI 36.1-58.2%, respectively) were statistically different (P = 0.009). Crude and adjusted Cox regression models identified malignancy as independently associated with death (adjusted HR = 3.92, 95% CI 1.76-8.73, P = 0.001).

CONCLUSIONS

HIV/AIDS was the predisposing condition in 84.8% of PML cases. The one-year case-fatality rate was 52.5% and having a malignancy was independently associated with death. This study reports emerging data on the epidemiology and outcome of PML in a middle-income country.

Progressive multifocal leukoencephalopathy secondary to idiopathic CD4 lymphocytopenia treated with pembrolizumab

BACKGROUND

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

METHODS

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

CONCLUSION

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

Progressive multifocal leukoencephalopathy triggered by COVID-19 in a previously asymptomatic person living with undiagnosed HIV infection

This report presents the case of a 47-year-old male patient who worked as a mathematics teacher and experienced the sudden onset of disorientation, aphasia, and acalculia during an online class. The current study reveals the first documented case of HIV and progressive multifocal leukoencephalopathy with the detection of SARS-CoV-2 and human polyomavirus 2 (previously known as John Cunningham virus) in the cerebrospinal fluid. Furthermore, serum analysis revealed elevated concentrations of interleukin (IL)-6, IL-17, and IL-8, which are potential factors known to reduce the expression of tight junctions and adhesion molecules in the extracellular matrix, thereby affecting the permeability of the blood-brain barrier. Finally, the study discusses whether SARS-CoV-2 triggers or exacerbates progressive multifocal leukoencephalopathy.

"Borderline" idiopathic CD4+ T-cell lymphocytopenia presenting with atypical progressive multifocal leukoencephalopathy

Idiopathic CD4+ lymphocytopenia (ICL) is a rare disorder characterized by low counts of CD4+ cells (<300/mm³) in absence of other known causes of immunosuppression. A few cases of progressive multifocal leukoencephalopathy (PML) were reported in association with ICL with variable outcome. We describe the case of a 40 year-old man diagnosed with PML, which showed a monophasic course. Causes of primary and secondary immunodeficiency were ruled out, only a "borderline" ICL was found. This case highlights that a severe immunodepression could not be an absolute prerequisite in developing PML and also points the attention on current definition of ICL.

Progressive Multifocal Leukoencephalopathy: Current Insights

Cases of PML should be evaluated according to predisposing factors, as these subgroups differ by incidence rate, clinical course, and prognosis. The three most significant groups at risk of PML are patients with hematological malignancies mostly previously treated with immunotherapies but also untreated, patients with HIV infection, and patients using monoclonal antibody (mAb) treatments. Epidemiological data is scarce and partly conflicting, but the distribution of the subgroups appears to have changed. While there is no specific anti-JCPyV treatment, restoration of the immune function is the most effective approach to PML treatment. Research is warranted to determine whether immune checkpoint inhibitors could benefit certain PML subgroups. There are no systematic national or international records of PML diagnoses or a risk stratification algorithm, except for MS patients receiving natalizumab (NTZ). These are needed to improve PML risk assessment and to tailor better prevention strategies.

Central Nervous System Infections Complicating Immunosuppression and Transplantation

PURPOSE OF REVIEW

This article reviews infections associated with cancer treatments and immunosuppressive/immunomodulatory therapies used in both neoplastic and non-neoplastic conditions, including hematopoietic cell transplantation and solid organ transplantation. It provides a clinical approach to the most commonly affected patient groups based on clinicoanatomic presentation and disease-specific risks resulting from immune deficits and drugs received.

RECENT FINDINGS

The clinical presentations, associated neuroimaging findings, and CSF abnormalities of patients with central nervous system infections who are immunocompromised may differ from those of patients with central nervous system infections who are immunocompetent and may be confused with noninfectious processes. Triggering of brain autoimmunity with emergence of neurotropic antibodies has emerged as a recognized parainfectious complication. New unbiased metagenomic assays to identify obscure pathogens help clinicians navigate the increasing range of conditions affecting the growing population of patients with altered immunity.

SUMMARY

Despite evidence-based prophylactic regimens and organism-specific antimicrobials, central nervous system infections continue to cause significant morbidity and mortality in an increasing range of patients who are immunocompromised by their conditions and therapies. Multiple new drugs put patients at risk for progressive multifocal leukoencephalopathy, which has numerous imaging and clinical manifestations; patients at risk include those with multiple sclerosis, for whom infection risk is becoming one of the most important factors in therapeutic decision making. Efficient, early diagnosis is essential to improve outcomes in these often-devastating diseases.

Progressive multifocal leukoencephalopathy: a challenging diagnosis established at autopsy

Progressive multifocal leukoencephalopathy (PML) is a feared entity that occurs most frequently in conditions of extreme immunodeficiency. The diagnosis is often made long after the onset of symptoms due to the physicians’ unfamiliarity, and the unavailability of diagnostic tests in some medical centers. Although the incidence of PML is decreasing among HIV patients with the advent of highly active antiretroviral therapy (HAART), in Brazil this entity is the fourth highest neurological complication among these patients. The authors present the case of a middle-aged man who tested positive for HIV concomitantly with the presentation of hyposensitivity in the face and the right side of the body, accompanied by mild weakness in the left upper limb. The clinical features worsened rapidly within a couple of weeks. The diagnostic work-up pointed to the working diagnosis of PML after brain magnetic resonance imaging; however, the detection of the John Cunningham virus (JCV) in the cerebral spinal fluid was negative. HAART was started but the patient died after 7 weeks of hospitalization. The autopsy revealed extensive multifocal patchy areas of demyelination in the white matter where the microscopy depicted demyelination, oligodendrocytes alterations, bizarre atypical astrocytes, and perivascular lymphocytic infiltration. The immunohistochemistry was positive for anti-SV40, and the polymerase chain reaction of the brain paraffin-embedded tissue was positive for JCV. The authors highlight the challenges for diagnosing PML, as well as the devastating outcome of PML among HIV patients.

The Incidence and Predisposing Factors of John Cunningham Virus-Induced Progressive Multifocal Leukoencephalopathy in Southern Finland: A Population-Based Study

Background

The aim of this study was to assess the prevalence, incidence rate (IR), predisposing factors, survival rate, and diagnostic delay of progressive multifocal leukoencephalopathy (PML) across medical specialties. Another objective was to survey how PML diagnosis was made in the studied cases.

Methods

This is a cross-sectional retrospective observational study of PML cases across different medical specialties during 2004–2016 in the Finnish Capital Region and Southern Finland. Data were obtained from clinical records, clinical microbiology, pathology and radiology department records, and human immunodeficiency virus (HIV) quality register medical records.

Results

A total of 31 patients were diagnosed with PML. The prevalence of PML was 1.56 per 100 000 people and the IR was 0.12 per 100 000 individuals per year during 2004–2016. Hematologic malignancies (n = 19) and HIV/acquired immune deficiency syndrome (n = 5) were the most common underlying diseases, and all patients who had malignant diseases had received cancer treatment. Before PML diagnosis, 21 (67.7%) patients were treated with chemotherapy, 14 (45.2%) patients with rituximab, and 1 patient (3.2%) with natalizumab. Two patients (6.5%) had no obvious immunocompromising disease or treatment. Neither gender, age, first symptoms, previous medication, nor underlying disease influenced the survival of PML patients significantly. The 5-year survival rate was poor, at less than 10%.

Conclusions

The majority of PML patients in our study had a predisposing disease or had immunosuppressive or monoclonal antibody therapy. In the future, broader use of immunosuppressive and immunomodulatory medications may increase incidence of PML among patients with diseases unassociated with PML. Safety screening protocols for John Cunningham virus and PML are important to prevent new PML cases.

Progressive multifocal leukoencephalopathy after fingolimod treatment

OBJECTIVE

We describe the characteristics of the 15 patients with fingolimod-associated progressive multifocal leukoencephalopathy (PML) identified from the Novartis data safety base and provide risk estimates for the disorder.

METHODS

The Novartis safety database was searched for PML cases with a data lock point of August 31, 2017. PML classification was based on previously published criteria. The risk and incidence were estimated using the 15 patients with confirmed PML and the overall population of patients treated with fingolimod.

RESULTS

As of August 31, 2017, 15 fingolimod-treated patients had developed PML in the absence of natalizumab treatment in the preceding 6 months. Eleven (73%) were women and the mean age was 53 years (median: 53 years). Fourteen of the 15 patients were treated with fingolimod for >2 years. Two patients had confounding medical conditions. Two patients had natalizumab treatment. This included one patient whose last dose of natalizumab was 3 years and 9 months before the diagnosis of PML. The second patient was receiving fingolimod for 4 years and 6 months, which was discontinued to start natalizumab and was diagnosed with PML 3 months after starting natalizumab. Absolute lymphocyte counts were available for 14 of the 15 patients and none exhibited a sustained grade 4 lymphopenia (≤200 cells/μL).

CONCLUSIONS

The risk of PML with fingolimod in the absence of prior natalizumab treatment is low. The estimated risk was 0.069 per 1,000 patients (95% confidence interval: 0.039-0.114), and the estimated incidence rate was 3.12 per 100,000 patient-years (95% confidence interval: 1.75-5.15). Neither clinical manifestations nor radiographic features suggested any unique features of fingolimod-associated PML.

Infections of the Nervous System

Microorganisms can affect the entire neuraxis, producing a variety of neurologic complications that frequently entail prolonged hospitalizations and complicated treatment regimens. The spread of pathogens to new regions and the reemergence of opportunistic organisms in immunocompromised patients pose increasing challenges to health care professionals. Because rapid diagnosis and treatment may prevent long-term neurologic sequelae, providers should approach these diseases with a structured, neuroanatomic framework, incorporating a thorough history, examination, laboratory analysis, and neuroimaging in their clinical reasoning and decision-making.

Progressive multifocal leukoencephalopathy associated with fumaric acid esters treatment in psoriasis patients

BACKGROUND

Fumaric acid esters (FAEs) are a systemic treatment for psoriasis considered to have a favourable long-term safety profile without an increased risk for immunosuppression. However, progressive multifocal leukoencephalopathy (PML), a rare, opportunistic viral infection of the central nervous system, has been linked anecdotally to FAE treatment.

OBJECTIVE

To assess clinical features and outcomes of FAE-associated PML cases.

METHODS

Systematic literature search in multiple databases up to 25th February 2016 for reports of PML in psoriasis patients treated with FAEs.

RESULTS

Eight cases (four male, four female) of FAE-associated PML were identified. Median age was 64 years (range 42-74 years); median FAE treatment duration was 3 years (range 1.5-5 years). Six patients were treated with a formulation containing dimethyl fumarate (DMF) and monoethyl fumarates, and two patients with a DMF formulation. Patients exhibited neurological symptoms, such as aphasia, hemiparesis and dysarthria. PML diagnosis was based on MRI findings and presence of JC virus in cerebrospinal fluid and/or brain tissue. All cases were linked to moderate-to-severe reductions in absolute lymphocyte counts, with nadirs ranging from 200 to 792 cells per mm³ . Median exposure to lymphocytopenia was 2 years (range 1-5 years). In all cases, FAE treatment was discontinued; PML was treated with mefloquine plus mirtazapine. Three patients improved, two had stable disease, two had residual symptoms, and one patient died to an immune reconstitution inflammatory syndrome.

CONCLUSION

Progressive multifocal leukoencephalopathy is infrequently linked to FAE treatment, but underreporting cannot be excluded. Physicians treating patients with FAEs should be vigilant for the occurrence of PML, and both clinicians and patients should be alert for onset of new neurological symptoms. Periodic monitoring of lymphocyte counts and FAE discontinuation in case of moderate-to-severe lymphocytopenia is recommended to minimize the risk for PML.

Progressive Multifocal Leukoencephalopathy in HIV-Uninfected Individuals

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

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.

Spinal Cord in Multiple Sclerosis: Magnetic Resonance Imaging Features and Differential Diagnosis

Multiple sclerosis (MS) is an idiopathic inflammatory disorder of the central nervous system that affects not only the brain but also the spinal cord. In the diagnostic and monitoring process of MS, spinal cord magnetic resonance imaging (MRI) is not performed as commonly as brain MRI, mainly because of certain technical difficulties and the increase in total acquisition time. Nonetheless, spinal cord MRI findings are important to establish a prompt accurate diagnosis of MS, impart prognostic information, and provide valuable data for monitoring the disease course in certain cases. In this article, we discuss the technical aspects of spinal cord MRI, the typical MRI features of the spinal cord in MS, the clinical indications for this examination, and the differential diagnosis with other disorders that may produce similar clinical or MRI findings.

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.

Progressive Multifocal Leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is a devastating demyelinating disease with significant morbidity and mortality and no effective, targeted therapies. It is most often observed in association with abnormalities of cell-mediated immunity, in particular human immunodeficiency virus (HIV) infection, but also occurs in association with lymphoproliferative diseases, certain immunosuppressive and immunomodulatory regimens, and other conditions. The etiologic agent of PML is a small, ubiquitous polyomavirus, the JC virus (JCV, also known as JCPyV), for which at least 50% of the adult general population is seropositive. PML results when JCV replicates within cerebral oligodendrocytes and astrocytes, leading to oligodendrocyte death and demyelination. Unfortunately, no treatments have been convincingly demonstrated to be effective, though some have been employed in desperation; treatment otherwise includes attempts to restore any immune system defect, such as the withdrawal of the causative agent if possible, and general supportive care.

Orderly Steps in Progression of JC Virus to Virulence in the Brain

Progressive multifocal leukoencephalopathy is a neurodegenerative disease caused by demyelination in the brain. The demyelination is due to infection of oligodendroglial cells by polyomavirus JC, a circular DNA virus. The virus resides as an archetype form in uroepithelial cells and bone marrow of more than 70% of adults, in whom it seldom causes overt symptoms. The JC viral form infecting the brain differs from the archetype. This viral form contains two deletions and a duplication in the non-coding control region that are thought to be derived from the archetype. These rearrangements are necessary for neurovirulence. This review considers how these rearrangements occur in the context of transit to the brain and adaptation to infect glial cells.

Viral diseases of the central nervous system

Virus-induced diseases of the central nervous system (CNS) represent a significant burden to human health worldwide. The complexity of these diseases is influenced by the sheer number of different neurotropic viruses, the diverse routes of CNS entry, viral tropism, and the immune system. Using a combination of human pathological data and experimental animal models, we have begun to uncover many of the mechanisms that viruses use to enter the CNS and cause disease. This review highlights a selection of neurotropic viruses that infect the CNS and explores the means by which they induce neurological diseases such as meningitis, encephalitis, and myelitis.

Safety issues and concerns of new immunomodulators in rheumatology

INTRODUCTION

The development of biologic therapies has been an enormous leap in the management of patients with rheumatoid and psoriatic arthritis. Since the first anti-TNF-α therapies, numerous molecules have been identified as targets of immunomodulatory therapies, such as IL-1 (anakinra, canakinumab), IL-6 (tocilizumab), CD20(+) B cells (rituximab), CTLA4 (abatacept) and two additional anti-TNF-α therapies (certolizumab pegol, golimumab).

AREAS COVERED

In the present review, we will describe the safety issues related to the immunosuppressive action of these biologic drugs that are mainly represented by infection and malignancy. The risk of infection should be identified before initiating a biologic treatment and markers checked over time, in particular for tuberculosis and hepatitis B and C viruses. Other infections (bacterial, viral, parasitic; opportunistic; surgery-related) and safety issues may require temporary interruption of the treatment until complete resolution. No significantly increased risk of malignancy, both hematological and solid, has been associated with the use of biologic agents. In all cases, it is difficult to dissect the risks related to biologics from those related to baseline treatments.

EXPERT OPINION

Detailed medical history and laboratory screening should be performed before starting biologic therapies. Clinicians should be aware of the different safety profiles associated with different molecules and they should follow up data coming out of the existing registries for biologics in regard to new or old side effects.