Pembrolizumab Treatment for Progressive Multifocal Leukoencephalopathy

BCMA-directed CAR T-cell therapy in patients with multiple myeloma and CNS involvement

ABSTRACT

We investigated B-cell maturation antigen-directed chimeric antigen receptor T-cell (CAR-T) therapy in patients with relapsed or refractory multiple myeloma (MM) and central nervous system (CNS) involvement. Ten patients received either idecabtagene vicleucel (n = 6) or ciltacabtagene autoleucel (n = 4), where brain/cranial nerve and/or spinal cord involvement/leptomeningeal disease were evident on either magnetic resonance imaging (100%) and/or cerebrospinal fluid (40%). Eight patients had their CNS diagnosis before CAR-T therapy, and two were diagnosed within 14 days post-infusion. Seven received CNS-directed therapy during bridging before CAR-T therapy. There were no excess toxicities: no cytokine release syndrome grade ≥3; 10% immune effector cell-associated neurotoxicity syndrome (ICANS) grade 3; and no ICANS grade 4. Two patients experienced delayed but treatable neurotoxicity, with no reported parkinsonian side effects. The best overall response rate was 80% (≥70% very good partial response) and a 100% CNS response. With a median follow-up of 381 days, patients with CNS myeloma diagnosed before CAR-T therapy (n = 8) had a median overall survival and progression-free survival (PFS) of 13.3 and 6.3 months, respectively. Best outcomes were observed in 4 patients who had a response to bridging therapy, suggesting that optimizing pre-CAR-T therapy may be key for improved outcomes. Our study suggests that CAR-T therapy in patients with CNS MM is safe and feasible, and screening for CNS involvement before CAR-T therapy could be warranted in high-risk patients. The excellent initial response but relatively short PFS suggests consideration for post-CAR-T maintenance. Larger studies are needed to confirm these findings.

Multiple Sclerosis and Other Acquired Demyelinating Diseases of the Central Nervous System

Acquired demyelinating diseases of the central nervous system (CNS) comprise inflammatory conditions, including multiple sclerosis (MS) and related diseases, as well as noninflammatory conditions caused by toxic, metabolic, infectious, traumatic, and neurodegenerative insults. Here, we review the spectrum of diseases producing acquired CNS demyelination before focusing on the prototypical example of MS, exploring the pathologic mechanisms leading to myelin injury in relapsing and progressive MS and summarizing the mechanisms and modulators of remyelination. We highlight the complex interplay between the immune system, oligodendrocytes and oligodendrocyte progenitor cells (OPCs), and other CNS glia cells such as microglia and astrocytes in the pathogenesis and clinical course of MS. Finally, we review emerging therapeutic strategies that exploit our growing understanding of disease mechanisms to limit progression and promote remyelination.

Therapeutic advances in multiple sclerosis: Novel therapies (immune checkpoint inhibitors, CAR-T, Anti-CD40L)

As patients with multiple sclerosis (MS) age, the risk of cancer also increases. Immune checkpoint inhibitors (ICIs) are novel monoclonal antibodies that have revolutionized cancer treatment. However, their use is limited by immune related adverse events. In patients with MS and pre-existing autoimmune disease there is concern that use of ICIs could worsen disease outcome. In the first part of this review we discuss the current data on ICIs and MS which overall suggest that they are well tolerated from the standpoint of MS disease activity. We recommend that MS not be a strict contraindication to ICI use which should depend on an individualized risk benefit discussion. In the second part, we focus on novel therapies for MS including CAR-T cell and anti-CD40L treatments. These newer therapies have the potential to address an unmet need in MS as they can cross the blood-brain and have the potential to target compartmentalized central nervous inflammation that may underly the pathophysiology of progressive MS.

Prolonged survival in HIV-associated Progressive Multifocal Leukoencephalopathy treated with Pembrolizumab: a case series on treatment and long-term follow-up

Progressive Multifocal Leukoencephalopathy (PML) is a rare opportunistic infection of the central nervous system (CNS) caused by human polyomavirus JC virus, with high mortality rate in people living with HIV (PLWH), without an effective specific treatment beside combined antiretroviral therapy (cART). The use of Pembrolizumab, an inhibitor of the Programmed cell death protein 1 (PD-1) receptor on T cells, has been associated with decreased viral clearance. Aim of this study is to evaluate clinical course of PLWH affected by PML treated with pembrolizumab. We report four consecutive PLWH with clinical and radiological evidence of PML and JCV-DNA detection in cerebrospinal fluid (CSF). Pembrolizumab was administered to all four PLWH alongside cART. Radiological and laboratory follow-up were performed at the end of the medical protocol. Clinically, 3 out of 4 PLWH showed an improvement in neurological deficits, partially reacquiring the lost functions, and they are alive at 3.5 years, 14 months, and 9 months, respectively; the fourth patient died shortly after treatment due to worsening respiratory conditions. In all the PLWH completing treatment, a decrease of about 80-90% of the specific PD-1 activity was observed. Prolonged survival and stabilization of radiological findings have been observed, along with clinical improvement and partial recovery of acquired deficits in 3 out of 4 PLWH. In addition, a decrease in anti-PD-1 expression has also been observed, suggesting a link between the therapy and the success achieved. Given the small sample and conflicting evidence in the existing literature, further investigation is needed to assess its effectiveness.

Phase Ib/II study of Pembrolizumab with Lanreotide depot for advanced, progressive Gastroenteropancreatic neuroendocrine tumors (PLANET)

While performing a study of immune checkpoint blockade with the anti-PD-1 antibody pembrolizumab combined with the somatostatin analogue (SSA) lanreotide in patients with low- and intermediate-grade gastroenteropancreatic neuroendocrine tumors (GEP-NETs), we studied whether there were any immune correlates of response to the anti-PD-1 therapy that could guide future attempts to integrate immunotherapy into the treatment of NETs. Patients with grade 1 and 2 GEP-NETs who had progressed on a prior SSA received lanreotide 90 mg subcutaneously and pembrolizumab 200 mg intravenously every 3 weeks until progression or intolerable toxicity. Objective response rate (ORR) at any time in the study, clinical benefit rate (CBR, defined as stable disease or better), progression-free survival (PFS), and overall survival (OS) were measured. Changes in T cell subsets in peripheral blood before and during therapy were analyzed by multiparameter mass cytometry (CyTOF). Archived tissue samples were analyzed for PD-L1 expression and TIL infiltration. Twenty-two (22) patients (GI/pancreatic 14/8, median Ki67 7% [IQR 4, 10%], median 1.5 prior systemic therapies [range 1-4]) were enrolled. Among the GI-NETs, there was one partial response, the CBR was 50%, the median PFS was 8.5 months, and the median OS was 32.7 months. No responses were seen in pancreatic NETs, which had 0% CBR, a PFS of 2.7 months, and an OS of 23.9 months. Of the 16 analyzable tumors, 6 had detectable PD-L1 expression and 15 had detectable TILs. Neither TILs nor PD-L1 expression correlated with ORR or CBR. However, clinical benefit (SD or better) was associated with peripheral blood on-treatment effector memory T cell activation and progressive disease was associated with baseline peripheral blood regulatory T cell (Treg) activation. We conclude that immune checkpoint blockade had low activity in unselected patients with grade 1 and 2 GEP-NETs. Further study of strategies to reduce Treg activation or enhance effector memory activation during immunotherapy is warranted.

ATM Expression and Activation in Ataxia Telangiectasia Patients with and without Class Switch Recombination Defects

BACKGROUND

Ataxia telangiectasia mutated (ATM) kinase plays a critical role in DNA double-strand break (DSB) repair. Ataxia telangiectasia (A-T) patients exhibit abnormalities in immunoglobulin isotype expression and class switch recombination (CSR). This study investigates the role of residual ATM kinase expression and activity in the severity of A-T disease.

METHODS

A-T patients with defined genetic diagnoses were classified based on CSR and based on the severity of their medical complications. Isolated peripheral blood mononuclear cells from any patient were evaluated before and after exposure to 0.5 Gy ionizing radiation for one minute. Western blotting was performed to identify the expression of ATM and phosphorylated ATM (p-ATM) proteins compared to age-sex-matched healthy controls.

RESULTS

In severe A-T patients (n = 6), the majority (66.7%) had frameshift mutations, while 33.3% had nonsense mutations in the ATM gene. The mild group (n = 3) had two cases of splice errors and one missense mutation. All patients with CSR defect had elevated IgM serum levels, whereas all switched immunoglobulins were reduced in them. Expression of ATM and p-ATM proteins was significantly lower (p = 0.01) in all patients compared to healthy controls, both pre-and post- and post-radiation. Additionally, low ATM and p-ATM protein expression levels were linked with the clinical severity of patients but were not correlated with CSR defects.

CONCLUSION

Expression and activation of ATM protein were defective in A-T patients compared to healthy controls. Altered expression of ATM and p-ATM proteins may have potential clinical implications for prognostic evaluation and symptom severity assessment in individuals with A-T.

Reemerging Infectious Diseases and Neuroimmunologic Complications

During the past decade (and beyond), neurologists have become aware of the emergence, persistence, and consequences of some familiar and new infections affecting the nervous system. Even among the familiar CNS infections, such as herpes virus, polyoma virus/JC, influenza, arbovirus, and hepatitis, challenges remain in developing effective antiviral treatments and treatments of postinfection sequelae. With the changing environment and increased global travel, arthropod vectors that mediate zoonotic disease transmission have spread unfamiliar viruses such as West Nile virus, dengue, chikungunya, equine encephalitis, and Zika, among others. Although the global health impact of these diseases has not risen to that of COVID-19 and HIV, it is likely to dramatically increase with continued spread of transmission vectors and the emergence of new zoonotic animal-to-human diseases mediated by those transmission vectors. Furthermore, specific virus-targeting treatments or effective vaccines for arboviral infections are not yet available, and this represents a major challenge in limiting the morbidity of these infections. By contrast, HIV-1, a disease that originated by direct transmission from nonhuman primates to humans (as early as the 1930s), after many years of intense study, is now targeted by highly specific and effective antiviral drugs that can limit the spread of infection and extend human life and health in all populations. Even with these dramatic therapeutic effects of suppressing HIV replication, neurologic dysfunction (primarily cognitive impairment) affects significant numbers of persons living with HIV. This emphasizes not only the importance of treating the underlying infection but also developing treatments for legacy effects of the initial infection even after antiviral therapy. Notably, the rapid emergence of SARS-CoV-2 infection was met with rapid implementation of highly effective and specific antiviral therapies. This resulted in early and dramatic lowering of the morbidity and mortality of SARS-CoV-2 infection. Nonetheless, the postinfectious complications of SARS-CoV-2 infection (long COVID) are now among the more costly consequences of emerging zoonotic infections worldwide. Developing new antiviral therapies that can penetrate the CNS, vaccines, and therapies that target host immune responses and metabolic dysfunction will be necessary for management of infectious and postinfectious complications of established and emerging infections.

Brain biopsy and pathological diagnosis for drug-associated progressive multifocal leukoencephalopathy (PML) with inflammatory reactions

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system caused by JC virus (JCV) infection. Although recognized as an AIDS complication in the 1980s, PML has emerged as a serious adverse event of immunosuppressive therapies since 2005, particularly disease-modifying drugs (DMDs) for multiple sclerosis (MS). PML can also occur in patients with collagenous diseases receiving steroid therapy or with age-related immunosuppression. In some cases, the etiology of immunosuppression remains unclear. These cases often present with early manifestations of PML, which, while common, are less well recognized, as PML was identified at more advanced stages in AIDS-related cases. Early diagnosis poses difficulty due to unfamiliar magnetic resonance (MR) images and low viral loads in cerebrospinal fluid (CSF), and brain biopsy may be conducted. This review summarizes the PML pathology identified through biopsy. Early cytopathological changes of JCV-infected cells, with the importance of dot-shaped inclusions associated with promyelocytic leukemia nuclear bodies (PML-NBs), are described. The variability of host immune responses, including PML immune reconstitution inflammatory syndrome (PML-IRIS), is addressed. The potential role of immune checkpoint inhibitors (ICIs), such as pembrolizumab, is also explored. Understanding the pathology of early PML helps to optimize diagnostic strategies and therapeutic interventions, ultimately improving prognosis.

PD-1 deficiency impairs eosinophil recruitment to tissue during Trichinella spiralis infection

Blockade of programmed cell death 1 (PD-1) is considered a promising strategy for controlling pathogen infection by enhancing host immune cell function. Eosinophils, which play a crucial role in type 2 immune responses, are essential components of the host defense against helminth infection. Here, we investigate the role of PD-1 in eosinophilia during Trichinella spiralis infection in mice. PD-1-deficient (PD-1-/-) mice exhibit delayed expulsion of adult worms and increased muscle larva burdens compared to wild-type mice following infection. Additionally, PD-1-/- mice display impaired recruitment of eosinophils to parasite-invaded tissues, attributed to decreased upregulation of adhesion molecules on both eosinophils and vascular endothelium after infection. The compromised Th2 cytokine response further contributes to impaired adhesion interactions, affecting eosinophil migration and cytotoxicity against larvae in vitro within T. spiralis-infected PD-1-/- mice. Our findings demonstrate a positive role for PD-1 in the recruitment of eosinophils, suggesting its involvement in host defense against helminth infection.

Antigen-Specific T Cell Receptor Discovery for Treating Progressive Multifocal Leukoencephalopathy

Background

Progressive multifocal leukoencephalopathy (PML) is a frequently fatal disease of the central nervous system caused by JC virus (JCV). Survival is dependent on early diagnosis and ability to re-establish anti-viral T cell immunity. Adoptive transfer of polyomavirus-specific T cells has shown promise; however, there are no readily available HLA-matched anti-viral T cells to facilitate rapid treatment.

Objective

Identify epitopes of the JCV major capsid protein VP1 that elicit an immune response in the context of human leukocyte antigen allele A*02:01 (HLA-A2) and isolate cognate T cell receptors (TCRs) from healthy donors. Evaluate individual VP1-specific TCRs for their capacity to be expressed in T cells and clear JCV in vitro .

Methods

PBMCs from HLA-A2+ healthy donors were stimulated with peptide libraries tiled across the JCV VP1 protein. Multiple rounds of stimulation were performed to identify the antigens that induced the largest expansion and CD8 + T cell response (measured as INF γ , TNF α , CD137, and CD69 expression). High-affinity, antigen-specific CD8 + T cells were isolated based on intensity of tetramer binding for downstream single-cell TCR sequencing. Candidate TCRs were selected based on tetramer binding affinity and activation assays. Promising TCRs were introduced into the T cell genome via viral transduction for in vitro validation including peptide-pulsed K562 cells and astrocyte cells, and JCV-infected astrocytes.

Results

Four conserved JCV VP1 epitopes (amino acids 100-108, 251-259, 253-262, and 274-283) presented by HLA-A2 were identified. VP1(100-108) consistently elicited the highest level of IFN- γ production from multiple donors and this peptide is in a highly conserved region of VP1. We next identified fourteen high avidity TCRs specific for VP1(100-108). When virally transduced into primary human T cells, seven of these TCRs demonstrated specific binding to VP1(100-108):HLA-A2 tetramers, and four showed increased IFN- γ response when incubated with peptide. Primary CD8 + T cells expressing two of these TCRs cleared both HLA-A2 positive K562 cells and HLA-A2 positive SVG astrocyte cell line presenting exogenously added VP1 peptide at a range of E:T ratios. In addition, both TCR-transduced T cell populations effectively lysed JCV-infected astrocytes.

Conclusions

We identified JCV VP1 epitopes that are immunogenic in the context of HLA-A2 MHC-I, including epitopes that have not been previously described. The VP1(100-108) epitope was used to isolate HLA-A2-restricted TCRs. When cloned into primary human CD8 + T cells, these TCRs recognized VP1 (100-108)-presenting targets, and the transduced T cells conferred cytotoxic activity and eliminated K562 and astrocyte cells displaying the VP1(100-108) peptide and not sham peptide, as well as JCV-infected astrocytes. Taken together, these data suggest that JCV VP1-specific TCRs could be appealing therapeutics for HLA-A2+ individuals with PML in whom intrinsic T cell immunity cannot be rescued.

Effect of the Antibody-mediated Immune Responses on COPD, Asthma, and Lung Function: A Mendelian Randomization Study

INTRODUCTION

The precise cause of antibody-mediated immune responses on chronic obstructive pulmonary disease (COPD), asthma, and lung function remains unclear. We characterized the relationship between antibody-mediated immune responses to COPD, asthma, and lung function, ultimately achieve the prevention or treatment.

METHODS

We obtained summary data from published genome-wide association studies, including antibody-mediated immune responses, COPD, asthma, forced expiratory volume in the first second (FEV1), forced expiratory volume (FVC), and FEV1/FVC. Bidirectional two-sample mendelian randomization (MR) analysis was used to assess causal relationships of antibody-mediated immune responses, COPD, asthma, FEV1, FVC, and FEV1/FVC.

RESULTS

A total of 20 antibody-mediated immune responses were identified have a significant causal effect on COPD, asthma, FEV1, and FVC, with six exhibiting reverse causality. Importantly, the results of the five MR analyses were almost identical with respect to the causal effect of anti-polyomavirus 2 IgG seropositivity and varicella zoster virus glycoprotein E and I antibody levels on the risk of COPD, asthma, FEV1, and FVC.

CONCLUSIONS

This study contributes to existing knowledge by investigating the causal relationship between antibody-mediated immune responses and respiratory conditions, including COPD, asthma, and lung function, using a two-sample MR design. The key findings can aid in identifying individuals at risk of these conditions and facilitate early prevention and diagnosis.

Exploring JC Polyomavirus Sequences and Human Gene Expression in Brain Tissue of Patients With Progressive Multifocal Leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is a rare neurological condition associated with reactivation of dormant JC polyomavirus (JCPyV). In this study, we characterized gene expression and JCPyV rearrangements in PML brain tissue. Infection of white matter astrocytes and oligodendrocytes as well as occasional brain cortex neurons was shown. PML brain harbored exclusively rearranged JCPyV variants. Viral transcripts covered the whole genome on both strands. Strong differential expression of human genes associated with neuroinflammation, blood-brain barrier permeability, and neurodegenerative diseases was shown. Pathway analysis revealed wide immune activation in PML brain. The study provides novel insights into the pathogenesis of PML.

Progressive multifocal leukoencephalopathy in systemic lupus erythematosus treated with pembrolizumab

This case report discusses a patient with systemic lupus erythematosus (SLE) treated with low-dose azathioprine who developed progressive multifocal leukoencephalopathy (PML). PML is a rare, severe, demyelinating disease linked to John Cunningham polyomavirus (JCV) reactivation.Treated with pembrolizumab, an immune checkpoint inhibitor, the patient initially improved. However, after the fourth dose, her condition rapidly worsened resulting in treatment discontinuation and death. Similar cases highlight the complex interplay of factors in PML development in SLE patients, including immunosuppression and genetic factors. The use of pembrolizumab in PML and SLE necessitates careful consideration of potential complications.

Progressive multifocal leukoencephalopathy in sarcoidosis successfully treated with pembrolizumab

Progressive multifocal leukoencephalopathy (PML) is a severe, demyelinating disease of the central nervous system caused by JC virus infection. The disease can be seen in sarcoidosis patients without additional risk factors. Here, we present an individual with PML secondary to sarcoidosis treated with 8 doses of pembrolizumab, a Programmed Cell-Death-1 (PD-1) Immune Checkpoint Inhibitor who showed significant improvement. This report illustrates the objective clinical and radiological improvement in a patient with PML due to sarcoidosis, and suggests further study of immune checkpoint inhibitors as a potential treatment for sarcoidosis patients with PML.

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

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

Highly restrictive and directional penetration of the blood cerebral spinal fluid barrier by JCPyV

The human polyomavirus JCPyV is an opportunistic pathogen that infects greater than 60% of the world's population. The virus establishes a persistent and asymptomatic infection in the urogenital system but can cause a fatal demyelinating disease in immunosuppressed or immunomodulated patients following invasion of the CNS. The mechanisms responsible for JCPyV invasion into CNS tissues are not known but direct invasion from the blood to the cerebral spinal fluid via the choroid plexus has been hypothesized. To study the potential of the choroid plexus as a site of neuroinvasion, we used an adult human choroid plexus epithelial cell line to model the blood-cerebrospinal fluid (B-CSF) barrier in a transwell system. We found that these cells formed a highly restrictive barrier to virus penetration either as free virus or as virus associated with extracellular vesicles (EVJC+). The restriction was not absolute and small amounts of virus or EVJC+ penetrated and were able to establish foci of infection in primary astrocytes. Disruption of the barrier with capsaicin did not increase virus or EVJC+ penetration leading us to hypothesize that virus and EVJC+ were highly cell-associated and crossed the barrier by an active process. An inhibitor of macropinocytosis increased virus penetration from the basolateral (blood side) to the apical side (CSF side). In contrast, inhibitors of clathrin and raft dependent transcytosis reduced virus transport from the basolateral to the apical side of the barrier. None of the drugs inhibited apical to basolateral transport suggesting directionality. Pretreatment with cyclosporin A, an inhibitor of P-gp, MRP2 and BCRP multidrug resistance transporters, restored viral penetration in cells treated with raft and clathrin dependent transcytosis inhibitors. Because choroid plexus epithelial cells are known to be susceptible to JCPyV infection both in vitro and in vivo we also examined the release of infectious virus from the barrier. We found that virus was preferentially released from the cells into the apical (CSF) chamber. These data show clearly that there are two mechanisms of penetration, direct transcytosis which is capable of seeding the CSF with small amounts of virus, and infection followed by directional release of infectious virions into the CSF compartment.

Solid organ transplant-related central nervous system infections

PURPOSE OF REVIEW

Central nervous system (CNS) infections in solid organ transplant (SOT) recipients may present atypical or nonspecific symptoms. Due to a wider range of infectious agents compared with immunocompetent hosts, diagnosis is challenging. This review categorizes CNS infections in SOT recipients by cause.

RECENT FINDINGS

New studies have reported new data on the epidemiology and the risk factors associated with each specific pathogen described in this review. Additionally, we included the treatment recommendations.

SUMMARY

The latest findings give us an insight into the different pathogens causing infectious neurologic complications in SOT recipients.

Sepsis in elderly patients: the role of neutrophils in pathophysiology and therapy

Sepsis is among the most important causes of mortality, particularly within the elderly population. Sepsis prevalence is on the rise due to different factors, including increasing average population age and the concomitant rise in the prevalence of frailty and chronic morbidities. Recent investigations have unveiled a "trimodal" trajectory for sepsis-related mortality, with the ultimate zenith occurring from 60 to 90 days until several years after the original insult. This prolonged temporal course ostensibly emanates from the sustained perturbation of immune responses, persevering beyond the phase of clinical convalescence. This phenomenon is particularly associated with the aging immune system, characterized by a broad dysregulation commonly known as "inflammaging." Inflammaging associates with a chronic low-grade activation of the innate immune system preventing an appropriate response to infective agents. Notably, during the initial phases of sepsis, neutrophils-essential in combating pathogens-may exhibit compromised activity. Paradoxically, an overly zealous neutrophilic reaction has been observed to underlie multi-organ dysfunction during the later stages of sepsis. Given this scenario, discovering treatments that can enhance neutrophil activity during the early phases of sepsis while curbing their overactivity in the later phases could prove beneficial in fighting pathogens and reducing the detrimental effects caused by an overactive immune system. This narrative review delves into the potential key role of neutrophils in the pathological process of sepsis, focusing on how the aging process impacts their functions, and highlighting possible targets for developing immune-modulatory therapies. Additionally, the review includes tables that outline the principal potential targets for immunomodulating agents.

Combined treatment with allogeneic Epstein-Barr- and human polyomavirus 1 specific T-cells in progressive multifocal leukoencephalopathy and EBV infection: a case report

Opportunistic viral infections in individuals with severe immunodeficiency can lead to fatal conditions such as progressive multifocal leukoencephalopathy (PML), for which treatment options are limited. These infections pose significant risks, especially when co-infections with other viruses occur. We describe a combined therapy approach using directly isolated allogeneic Human Polyomavirus 1 (also known as BKV) and Epstein-Barr virus (EBV) specific cytotoxic T-cells for the treatment of PML in conjunction with identified EBV in the cerebrospinal fluid (CSF) of a male patient infected with human immunodeficiency virus (HIV). A 53-year-old HIV-positive male, recently diagnosed with PML, presented with rapidly worsening symptoms, including ataxia, tetraparesis, dysarthria, and dysphagia, leading to respiratory failure. The patient developed PML even after commencing highly active antiretroviral therapy (HAART) 3 months prior. Brain magnetic resonance imaging (MRI) revealed multifocal demyelination lesions involving the posterior fossa and right thalamus suggestive of PML. In addition to the detection of human polyomavirus 2 (also known as JCV), analysis of CSF showed positive results for EBV deoxyribonucleic acid (DNA). His neurological condition markedly deteriorated over the following 2 months. Based on MRI, there was no evidence of Immune Reconstitution Inflammatory Syndrome contributing to this decline. The patient did not have endogenous virus-specific T-cells. We initiated an allogeneic, partially human leukocyte antigen-matched transfer of EBV and utilizing the cross-reactivity between BKV and JCV-BKV specific T-cells. This intervention led to notable neurological improvement and partial resolution of the MRI lesions within 6 weeks. Our case of a patient with acquired immune deficiency syndrome demonstrates that PML and concurrent EBV co-infection can still occur despite undergoing HAART treatment. This innovative experimental therapy, involving a combination of virus-specific T-cells, was demonstrated to be an effective treatment option in this patient.

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.

Hemorrhagic cystitis induced by JC polyomavirus infection following COVID-19: a case report

JC polyomavirus (JCPyV) is a human polyomavirus that can establish lifelong persistent infection in the majority of adults. It is typically asymptomatic in immunocompetent individuals. However, there is a risk of developing progressive multifocal leukoencephalopathy (PML) in immunocompromised or immunosuppressed patients. Though JCPyV commonly resides in the kidney-urinary tract, its involvement in urinary system diseases is extremely rare. Here, we reported a case of a 60-year-old male patient with coronavirus disease 2019 (COVID-19) infection who developed hemorrhagic cystitis after receiving treatment with nirmatrelvir 300 mg/ritonavir 100 mg quaque die (QD). Subsequent metagenomic next-generation sequencing (mNGS) confirmed the infection to be caused by JCPyV type 2. Then, human immunoglobulin (PH4) for intravenous injection at a dose of 25 g QD was administered to the patient. Three days later, the hematuria resolved. This case illustrates that in the setting of compromised host immune function, JCPyV is not limited to causing central nervous system diseases but can also exhibit pathogenicity in the urinary system. Moreover, mNGS technology facilitates rapid diagnosis of infectious etiology by clinical practitioners, contributing to precise treatment for patients.

Pathology for severe inflammatory PML with PD1/PD-L1 expression of favorable prognosis: What's a prognostic factor for PML-IRIS?

A 72-year-old woman with dermatomyositis (DM) developed neurological manifestation, and magnetic resonance imaging (MRI) revealed multiple T2/fluid-attenuated inversion recovery (FLAIR)-hyperintense lesions predominantly in the deep white matter of the cerebral hemisphere. Punctate or linear contrast enhancement was observed surrounding the T1-hypointense area. Multiple T2/FLAIR-hyperintense lesions were aligned along with the corona radiata. Malignant lymphoma was first suspected, and a brain biopsy was performed. Pathological investigation suggested the provisional diagnosis of "suspicious of malignant lymphoma." Owing to emergent clinical conditions, high-dose methotrexate (MTX) therapy was conducted, and then T2/FLAIR-hyperintense lesions were dramatically reduced. However, the diagnosis of malignant lymphoma was concerning since multiplex PCR demonstrated clonal restriction of the Ig H gene for B cells and TCR beta genes for T cells. Histopathology revealed the infiltration of both CD4+ and CD8+ T cells, and the CD4+ /CD8+ ratio was 4.0. Moreover, prominent plasma cells were observed, in addition to CD20+ B cells. Atypical cells with enlarged nuclei were present, and they were not hematopoietic but found as glial cells. JC virus (JCV) infection was verified with both immunohistochemistry and in situ hybridization; the final diagnosis was progressive multifocal leukoencephalopathy (PML). The patient was treated with mefloquine and discharged. This case is informative in understanding the host anti-viral response. Variable inflammatory cells were observed, including CD4+ and CD8+ T cells, plasma cells, and a small amount of perivascular CD20+ B cells. PD-1 and PD-L1 expression was observed in lymphoid cells and macrophages, respectively. PML with inflammatory reactions was thought fatal, and autopsy cases of PML with immune reconstitution inflammatory syndrome (IRIS) demonstrated excessive infiltration of only CD8+ T cells. However, this case revealed infiltration of variable inflammatory cells, and a favorable prognosis would be expected under PD-1/PD-L1 immune-checkpoint regulation.

Cerebellar progressive multifocal leucoencephalopathy identified by the shrimp sign

Progressive multifocal leucoencephalopathy (PML) is a demyelinating disease caused by the John Cunningham (JC) virus, which may get reactivated under certain immunosuppressive states such as AIDS, immunomodulatory therapy and haematological malignancies. PML has been reported rarely even in immunocompetent individuals where no immunodeficiency was present. PML characteristically involves periventricular and juxtacortical white matter. Isolated cerebellar or brainstem PML may be seen rarely. We present a case of a man in his 70s who presented with rapidly progressive cerebellar ataxia, ptosis and bipyramidal signs. Investigations excluded a direct viral cerebellar infection, acute disseminated encephalomyelitis, paraneoplastic cerebellar degeneration or any structural cerebellar lesion. MRI PET study revealed the classical shrimp sign which raised the possibility of cerebellar PML, and the same was confirmed by a positive JC virus PCR in the cerebrospinal fluid. Our patient had no known immune-compromising state, but further workup revealed a low CD4 count suggestive of idiopathic CD4 lymphopenia. The case illustrates the importance of the shrimp sign on MRI, the possibility of cerebellar involvement of PML as well as the need to consider a differential diagnosis of PML even in individuals with no obvious immunocompromised state.

[Progressive multifocal leukoencephalopathy in HIV-positive individuals]

The article discusses the historical aspect and modern ideas about the etiology and pathogenesis of progressive multifocal leukoencephalopathy in patients with HIV infection. An analysis and synthesis of literature data on the clinical presentation of this pathology was carried out. The possibilities and limitations of laboratory and instrumental diagnostic methods, including neuroimaging methods, are discussed in detail. The pathomorphological signs of the disease in HIV-positive individuals are covered.

Infectious leukoencephalopathies

Leukoencephalopathy from infectious agents may have a rapid course, such as human simplex virus encephalitis; however, in many diseases, it may take months or years before diagnosis, such as in subacute sclerosing panencephalitis or Whipple disease. There are wide geographic distributions and susceptible populations, including both immunocompetent and immunodeficient patients. Many infections have high mortality rates, such as John Cunningham virus and subacute sclerosing panencephalitis, although others have effective treatments if suspected and treated early, such as herpes simplex encephalitis. This chapter will describe viral, bacterial, and protozoal infections, which predominantly cause leukoencephalopathy. We focus on the clinical presentation of these infectious agents briefly covering epidemiology and subtypes of infections. Next, we detail current pathophysiologic mechanisms causing white matter injury. Diagnostic and confirmatory tests are discussed. We cover predominantly MRI imaging features of leukoencephalopathies, and in addition, summarize the common imaging features. Additionally, we detail how imaging features may be used to narrow the differential of a leukoencephalopathy clinical presentation. Lastly, we present an outline of common treatment approaches where available.

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.

Multiple faces of multiple sclerosis in the era of highly efficient treatment modalities: Lymphopenia and switching treatment options challenges daily practice

The expanded treatment landscape in relapsing-remitting multiple sclerosis (MS) has resulted in highly effective treatment options and complexity in managing disease- or drug-related events during disease progression. Proper decision-making requires thorough knowledge of the immunobiology of MS itself and an understanding of the main principles behind the mechanisms that lead to secondary autoimmunity affecting organs other than the central nervous system as well as opportunistic infections. The immune system is highly adapted to both environmental and disease-modifying agents. Immune reconstitution following cell depletion or cell entrapment therapies eliminates pathogenic aspects of the disease but can also lead to distorted immune responses with harmful effects. Atypical relapses occur with second-line treatments or after their discontinuation and require appropriate clinical decisions. Lymphopenia is a result of the mechanism of action of many drugs used to treat MS. However, persistent lymphopenia and cell-specific lymphopenia could result in disease exacerbation, secondary autoimmunity, or the emergence of opportunistic infections. Clinicians treating patients with MS should be aware of the multiple faces of MS under novel, efficient treatment modalities and understand the intricate brain-immune cell interactions in the context of an altered immune system. MS relapses and disease progression still occur despite the current treatment modalities and are mediated either by failure to control effector mechanisms inherent to MS pathophysiology or by new drug-related mechanisms. The multiple faces of MS due to the highly adapted immune system of patients impose the need for appropriate switching therapies that safeguard disease remission and further clinical improvement.

Pembrolizumab for the treatment of progressive multifocal leukoencephalopathy in China

The aim of this study is to analyze the clinical characteristics and outcomes of Chinese patients with progressive multifocal leukoencephalopathy (PML) who were treated with programmed cell death protein 1 (PD1) blockade therapies. We retrospectively analyzed patients who were admitted to our hospital between October 1, 2020, and October 1, 2022, diagnosed with PML and treated with PD1 blockade therapies. Four patients with PML who were treated with PD1 blockade therapies were identified. All patients were male, and their ages ranged from 19 to 54 years old. One patient (Case 2) exhibited mild pleocytosis, while three patients (Cases 2-4) had markedly reduced T lymphocyte cell counts prior to treatment. The time interval between symptom onset and treatment initiation ranged from six to 54 weeks. All patients received pembrolizumab treatment, with a total of two to four doses administered. Three patients who responded to pembrolizumab treatment showed clinical improvement starting around 8 weeks after the initiation of therapy. Although one patient did not show clinical improvement, they ultimately survived until the last follow-up. None of the patients in this study exhibited immune-related adverse events or immune reconstitution inflammatory syndrome. PD1 blockade appears to be a promising novel therapeutic option for PML; additional prospective studies are necessary to confirm its efficacy.

Survival and prognostic factors of progressive multifocal leukoencephalopathy in people living with HIV in modern ART era

Background

The incidence of progressive multifocal leukoencephalopathy (PML) in people living with HIV (PLWH) is 2%-4%. Currently, there is no effective therapeutic strategy for the treatment of PML in PLWH, resulting in a mortality of up to 50%. This study aimed to identify risk factors of death and prognostic markers in people living with HIV with PML.

Methods

A retrospective cohort study of AIDS-related PML individuals was conducted from January 1, 2015, to October 1, 2022, in Shanghai, China. PLWH who were diagnosed with PML for the first time were included. Kaplan-Meier curve and Cox regression were used to analyze the survival and its predictors. Levels of inflammatory markers and immune checkpoint inhibitors in blood and cerebrospinal fluid (CSF) were measured in the prestored samples using bead-based multiplex assay Indolamine 2,3-dioxygenase was determined using ELISA.

Results

Twenty of 71 subjects had initiated antiretroviral therapy (ART) before PML onset and no patients discontinued ART during this period. In total, 34 patients (47.9%) had opportunistic infections (OIs), the median CD4+ T cell count was 73.0 (33.0-149.0) cells/μL. The estimated probability of survival at six months was 78% (95% confidential intervals [CIs]:0.63-0.85). OIs, low CD4+ T cell count were associated with lower estimated six-month survival (hazard ratio 8.01, 95% CIs: 1.80-35.00, P=0.006 and 5.01, 95% CIs:1.57-16.03, p=0.007). Indolamine 2,3-dioxygenase activity in CSF of non-survivors group were higher than survivors group (p<0.05).

Conclusions

The survival rate of AIDS-related PML in the modern ART era was higher than the survival rate a decade ago. Low CD4+T cell count, OIs, were all associated with death of individuals with AIDS-related PML. The role of IDO in AIDS-related PML warrant further investigation.

Progressive Multifocal Leukoencephalopathy in Systemic Lupus Erythematosus: A Consequence of Patient-Intrinsic or -Extrinsic Factors?

Progressive multifocal leukoencephalopathy (PML) is a severe demyelinating disease of the central nervous system (CNS) caused by reactivation of the polyomavirus JC (JCV) typically in immunocompromised individuals. The risk of PML among rheumatic diseases may be higher for systemic lupus erythematosus (SLE), without, however, a clear association with the type and intensity of background therapy. We present the development and outcome of PML in a 32-year-old female lupus patient under mild immunosuppressive treatment, yet with marked B-cell lymphopenia in the peripheral blood and bone marrow (<1% of total lymphocytes). Despite treatment with the immune checkpoint inhibitor pembrolizumab, the patient showed progressive neurological and brain imaging deterioration and eventually died 15 months after PML diagnosis. To unveil possible underlying genetic liabilities, whole exome sequencing was performed which identified deleterious variants in GATA2 and CDH7 genes, which both have been linked to defective T- and/or B-lymphocyte production. These findings reiterate the possible role of disease-/patient-intrinsic factors, rather than that of drug-induced immunosuppression, in driving immune dysregulation and susceptibility to PML in certain patients with SLE.

Polyomavirus Wakes Up and Chooses Neurovirulence

JC polyomavirus (JCPyV) is a human-specific polyomavirus that establishes a silent lifelong infection in multiple peripheral organs, predominantly those of the urinary tract, of immunocompetent individuals. In immunocompromised settings, however, JCPyV can infiltrate the central nervous system (CNS), where it causes several encephalopathies of high morbidity and mortality. JCPyV-induced progressive multifocal leukoencephalopathy (PML), a devastating demyelinating brain disease, was an AIDS-defining illness before antiretroviral therapy that has "reemerged" as a complication of immunomodulating and chemotherapeutic agents. No effective anti-polyomavirus therapeutics are currently available. How depressed immune status sets the stage for JCPyV resurgence in the urinary tract, how the virus evades pre-existing antiviral antibodies to become viremic, and where/how it enters the CNS are incompletely understood. Addressing these questions requires a tractable animal model of JCPyV CNS infection. Although no animal model can replicate all aspects of any human disease, mouse polyomavirus (MuPyV) in mice and JCPyV in humans share key features of peripheral and CNS infection and antiviral immunity. In this review, we discuss the evidence suggesting how JCPyV migrates from the periphery to the CNS, innate and adaptive immune responses to polyomavirus infection, and how the MuPyV-mouse model provides insights into the pathogenesis of JCPyV CNS disease.

The prospect of universal coronavirus immunity: characterization of reciprocal and non-reciprocal T cell responses against SARS-CoV2 and common human coronaviruses

T cell immunity plays a central role in clinical outcomes of Coronavirus Infectious Disease 2019 (COVID-19) and T cell-focused vaccination or cellular immunotherapy might provide enhanced protection for some immunocompromised patients. Pre-existing T cell memory recognizing SARS-CoV-2 antigens antedating COVID-19 infection or vaccination, may have developed as an imprint of prior infections with endemic non-SARS human coronaviruses (hCoVs) OC43, HKU1, 229E, NL63, pathogens of "common cold". In turn, SARS-CoV-2-primed T cells may recognize emerging variants or other hCoV viruses and modulate the course of subsequent hCoV infections. Cross-immunity between hCoVs and SARS-CoV-2 has not been well characterized. Here, we systematically investigated T cell responses against the immunodominant SARS-CoV-2 spike, nucleocapsid and membrane proteins and corresponding antigens from α- and β-hCoVs among vaccinated, convalescent, and unexposed subjects. Broad T cell immunity against all tested SARS-CoV-2 antigens emerged in COVID-19 survivors. In convalescent and in vaccinated individuals, SARS-CoV-2 spike-specific T cells reliably recognized most SARS-CoV-2 variants, however cross-reactivity against the omicron variant was reduced by approximately 47%. Responses against spike, nucleocapsid and membrane antigens from endemic hCoVs were significantly more extensive in COVID-19 survivors than in unexposed subjects and displayed cross-reactivity between α- and β-hCoVs. In some, non-SARS hCoV-specific T cells demonstrated a prominent non-reciprocal cross-reactivity with SARS-CoV-2 antigens, whereas a distinct anti-SARS-CoV-2 immunological repertoire emerged post-COVID-19, with relatively limited cross-recognition of non-SARS hCoVs. Based on this cross-reactivity pattern, we established a strategy for in-vitro expansion of universal anti-hCoV T cells for adoptive immunotherapy. Overall, these results have implications for the future design of universal vaccines and cell-based immune therapies against SARS- and non-SARS-CoVs.

Tumor microenvironment-induced tumor cell plasticity: relationship with hypoxic stress and impact on tumor resistance

The role of tumor interaction with stromal components during carcinogenesis is crucial for the design of efficient cancer treatment approaches. It is widely admitted that tumor hypoxic stress is associated with tumor aggressiveness and thus impacts susceptibility and resistance to different types of treatments. Notable biological processes that hypoxia functions in include its regulation of tumor heterogeneity and plasticity. While hypoxia has been reported as a major player in tumor survival and dissemination regulation, the significance of hypoxia inducible factors in cancer stem cell development remains poorly understood. Several reports indicate that the emergence of cancer stem cells in addition to their phenotype and function within a hypoxic tumor microenvironment impacts cancer progression. In this respect, evidence showed that cancer stem cells are key elements of intratumoral heterogeneity and more importantly are responsible for tumor relapse and escape to treatments. This paper briefly reviews our current knowledge of the interaction between tumor hypoxic stress and its role in stemness acquisition and maintenance. Our review extensively covers the influence of hypoxia on the formation and maintenance of cancer stem cells and discusses the potential of targeting hypoxia-induced alterations in the expression and function of the so far known stem cell markers in cancer therapy approaches. We believe that a better and integrated understanding of the effect of hypoxia on stemness during carcinogenesis might lead to new strategies for exploiting hypoxia-associated pathways and their targeting in the clinical setting in order to overcome resistance mechanisms. More importantly, at the present time, efforts are oriented towards the design of innovative therapeutical approaches that specifically target cancer stem cells.

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

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

Revisiting JC virus and progressive multifocal leukoencephalopathy

Since its definition 65 years ago, progressive multifocal leukoencephalopathy (PML) has continued to devastate a growing population of immunosuppressed patients despite major advances in our understanding of the causative JC virus (JCV). Unless contained by the immune system, JCV lyses host oligodendrocytes collateral to its life cycle, leading to demyelination, neurodegeneration, and death. Novel treatments have stagnated in the absence of an animal model while current antiviral agents fail to address the now ubiquitous polyomavirus. In this review, we highlight the established pathogenesis by which JCV infection progresses to PML, highlighting major challenges that must be overcome to eliminate the underlying virus and, therefore, the debilitating disease.

An atypical case of progressive multifocal leukoencephalopathy in a patient with high grade B-cell lymphoma causing diagnostic delay

Progressive multifocal leukoencephalopathy (PML) is a rare disease of the central nervous system caused by opportunistic infection with JC virus. It presents in patients who are immunocompromised, and diagnosis is made by correlating clinical findings and radiological changes with the detection of JC virus in cerebrospinal fluid. Rarely, a brain biopsy is needed. A 72 year old with high grade B-cell lymphoma developed right arm weakness and limb ataxia shortly after his diagnosis. CNS involvement was excluded with a normal CT head, MRI brain/spine, and CSF examination. A paraneoplastic cause was suspected, and he received 5 cycles of Rituximab-containing chemotherapy to a complete metabolic remission. His neurology evolved during treatment despite serial MRI and CSF examination remaining normal. CSF and serum were both negative for JC virus by PCR. Following completion of chemotherapy, he deteriorated acutely with seizures and personality changes. It was only at this point that a repeat MRI showed new multiple scattered ring enhancing lesions within both cerebral hemispheres. The patient underwent a brain biopsy confirming JC virus positive-PML by immunohistochemistry and passed away one month later. This case illustrates the diagnostic challenges associated with PML and had several atypical features which led to diagnostic delay, specifically the onset of symptoms before starting immunochemotherapy, and the lack of radiological change despite evolving neurology. The eventual MRI abnormalities were not altogether classical for PML which, coupled with the JC-negativity in CSF and serum, meant a brain biopsy was required to reach the diagnosis.

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.

Secondary Central Nervous System Demyelinating Disorders in the Elderly: A Narrative Review

Secondary demyelinating diseases comprise a wide spectrum group of pathological conditions and may either be attributed to a disorder primarily affecting the neurons or axons, followed by demyelination, or to an underlying condition leading to secondary damage of the myelin sheath. In the elderly, primary demyelinating diseases of the central nervous system (CNS), such as multiple sclerosis, are relatively uncommon. However, secondary causes of CNS demyelination may often occur and in this case, extensive diagnostic workup is usually needed. Infectious, postinfectious, or postvaccinal demyelination may be observed, attributed to age-related alterations of the immune system in this population. Osmotic disturbances and nutritional deficiencies, more commonly observed in the elderly, may lead to conditions such as pontine/extrapontine myelinolysis, Wernicke encephalopathy, and demyelination of the posterior columns of the spinal cord. The prevalence of malignancies is higher in the elderly, sometimes leading to radiation-induced, immunotherapy-related, or paraneoplastic CNS demyelination. This review intends to aid clinical neurologists in broadening their diagnostic approach to secondary CNS demyelinating diseases in the elderly. Common clinical conditions leading to secondary demyelination and their clinical manifestations are summarized here, while the current knowledge of the underlying pathophysiological mechanisms is additionally presented.

Virus-Specific T-Cell Therapy for Viral Infections of the Central Nervous System: A Review

Opportunistic viral infections of the central nervous system represent a significant cause of morbidity and mortality among an increasing number of immunocompromised patients. Since antiviral treatments are usually poorly effective, the prognosis generally relies on the ability to achieve timely immune reconstitution. Hence, strategies aimed at reinvigorating antiviral immune activity have recently emerged. Among these, virus-specific T-cells are increasingly perceived as a principled and valuable tool to treat opportunistic viral infections. Here we briefly discuss how to develop and select virus-specific T-cells, then review their main indications in central nervous system infections, including progressive multifocal leukoencephalopathy, CMV infection, and adenovirus infection. We also discuss their potential interest in the treatment of progressive multiple sclerosis, or EBV-associated central nervous system inflammatory disease. We finish with the key future milestones of this promising treatment strategy.

Newly diagnosed AIDS patient with cerebellar JC virus

We present a case of a 57-year-old man with newly diagnosed acquired immunodeficiency syndrome (AIDS) infection who initially sought care for progressive dysarthria and gait instability. Neuroimaging and CSF studies revealed a diagnosis of progressive multifocal leukoencephalopathy (PML). Although the patient's human immunodeficiency virus (HIV) decreased considerably in response to anti-retroviral therapy, he continued to deteriorate clinically. Ultimately, the central nervous system (CNS) lesions, which were once centered in the cerebellum, became expansile throughout his posterior fossa. There are few reported cases of cerebellar PML in patients with AIDS.

Clinical Reasoning: Progressive Hemiparesis and White Matter Abnormalities in an HIV-Negative Patient

A 61-year-old man from India was admitted to hospital after being found unresponsive by the roadside. He was treated with dual-antiplatelet therapy for an acute coronary syndrome. Ten days into admission, he had mild left-sided face, arm, and leg weakness, which progressed significantly over the next 2 months in association with progressive white matter abnormalities on brain MRI. In this case study, we outline our clinical reasoning, which led to the detection of a rare underlying cause of a devastating neurologic disease. We also present our approach to treatment, which achieved a sustained clinical and radiologic response.

Characteristics of Progressive Multifocal Leukoencephalopathy Associated With Sarcoidosis Without Therapeutic Immune Suppression

Importance

Progressive multifocal leukoencephalopathy can occur in the context of systemic sarcoidosis (S-PML) in the absence of therapeutic immune suppression and can initially be mistaken for neurosarcoidosis or other complications of sarcoidosis. Earlier recognition of S-PML could lead to more effective treatment of the disease.

Objective

To describe characteristics of patients with S-PML.

Design, Setting, and Participants

For this case series, records from 8 academic medical centers in the United States were reviewed from 2004 to 2022. A systematic review of literature from 1955 to 2022 yielded data for additional patients. Included were patients with S-PML who were not receiving therapeutic immune suppression. The median follow-up time for patients who survived the acute range of illness was 19 months (range, 2-99). Data were analyzed in February 2023.

Exposures

Sarcoidosis without active therapeutic immune suppression.

Main Outcomes and Measures

Clinical, laboratory, and radiographic features of patients with S-PML.

Results

Twenty-one patients with S-PML not receiving therapeutic immune suppression were included in this study, and data for 37 patients were collected from literature review. The median age of the 21 study patients was 56 years (range, 33-72), 4 patients (19%) were female, and 17 (81%) were male. The median age of the literature review patients was 49 years (range, 21-74); 12 of 34 patients (33%) with reported sex were female, and 22 (67%) were male. Nine of 21 study patients (43%) and 18 of 31 literature review patients (58%) had simultaneous presentation of systemic sarcoidosis and PML. Six of 14 study patients (43%) and 11 of 19 literature review patients (58%) had a CD4+ T-cell count greater than 200/μL. In 2 study patients, a systemic flare of sarcoidosis closely preceded S-PML development. Ten of 17 study patients (59%) and 21 of 35 literature review patients (60%) died during the acute phase of illness. No meaningful predictive differences were found between patients who survived S-PML and those who did not.

Conclusions and Relevance

In this case series, patients with sarcoidosis developed PML in the absence of therapeutic immune suppression, and peripheral blood proxies of immune function were often only mildly abnormal. Systemic sarcoidosis flares may rarely herald the onset of S-PML. Clinicians should consider PML in any patient with sarcoidosis and new white matter lesions on brain magnetic resonance imaging.

Progressive multifocal leukoencephalopathy in multiple myeloma

Progressive multifocal leukoencephalopathy (PML) is a rare and often fatal demyelinating disease of the central nervous system caused by reactivation of the JC virus in the context of immune suppression such as HIV, malignancy, and certain immunomodulatory medications. PML has been reported only rarely in multiple myeloma patients, and its presenting features and natural history in this population are not well known. We describe six cases of PML among multiple myeloma patients treated at our institution between 2013 and 2022, including two that developed on or shortly after treatment with recently developed BCMA-directed immunotherapies.