PML-IRIS in patients with HIV infection: clinical manifestations and treatment with steroids

Neuroimaging Insights Into Early Stages of HIV-Progressive Multifocal Leukoencephalopathy: A Case Report

This report aims to enhance the understanding of early longitudinal neuroimaging features of progressive multifocal leukoencephalopathy (PML) in human immunodeficiency virus (HIV). Neuroimaging has become crucial in the diagnosis and early recognition of PML. Recognition of magnetic resonance imaging (MRI) features in the early stages of PML is paramount to avoid misdiagnosis and facilitate the delivery of treatments aimed at reducing disease progression. A 49-year-old white man with HIV presented with 4-month progressive left-sided weakness. Neurological examination revealed mild cognitive impairment, left-sided hemiparesis, and somatosense impairment to all modalities. Brain MRI revealed a punctate pattern with innumerable T2-FLAIR (fluid attenuated inversion recovery) hyperintensities in the cortex, brainstem, cerebellum, subcortical, and periventricular areas. Susceptibility-weighted imaging (SWI) revealed hypointensities involving subcortical U-fibers and cortical architecture. A comprehensive diagnostic evaluation was inconclusive. John Cunningham virus (JCV) PCR in cerebrospinal fluid (CSF) was indeterminate. He was started on antiretroviral therapy. Repeat brain MRI performed 1.5 months later, in the setting of further neurological decline, demonstrated progression of the T2-hyperintensities into a large confluent white matter lesion in the right frontoparietal lobe. Despite an indeterminate JCV PCR, the appearance and characteristic progression of the lesions in successive imaging in the setting of severe immunosuppression, with extensive negative infectious workup, was indicative of PML. This clinical experience illustrates unique neuroimaging features of HIV-PML in early stages and its progression over time. It especially highlights the relevance of the SWI sequence in the diagnosis and features observed with disease evolution. Short-term imaging follow-up may assist with the recognition of MRI features consistent with the biology of the infection.

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

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

Treatment of Progressive Multifocal Leukoencephalopathy Using Immune Restoration

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

Progressive multifocal leukoencephalopathy presenting with acute sensorineural hearing loss in an intestinal transplant recipient

A 20-year-old male presented 3.5 years after intestinal transplantation with rapidly progressive sensorineural hearing loss. Initial brain imaging was consistent with inflammation and/or demyelination. Lumbar puncture was initially non-diagnostic and a broad infectious workup was unrevealing. Three months after presentation, a repeat LP detected JC virus for which tests had not earlier been conducted. He continued to deteriorate despite withdrawal of prior immunosuppression and addition of mirtazapine, maraviroc, and steroids. He died of progressive neurologic decompensation 5 months after his initial presentation. This case highlights progressive multifocal leukoencephalopathy (PML) as a rare complication after solid organ transplantation and acute sensorineural hearing loss as an unusual first presenting symptom of PML. JC virus should be considered in the differential diagnosis of acute sensorineural hearing loss in any immunocompromised patient.

Checkpoint inhibitors for the treatment of JC virus-related progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is a frequently fatal brain infection caused by the JC polyomavirus (JCV). PML occurs in people with impaired cellular immunity, and the only effective treatment is restoration of immune function. Infection in immunocompromised hosts is often associated with immune exhaustion, which is mediated by inhibitory cell surface receptors known as immune checkpoints, leading to loss of T cell effector function. Blockade of immune checkpoints can reinvigorate host responses to fight infection. Recently, there have been several reports of checkpoint blockade to treat PML in patients in whom immune reconstitution is otherwise not possible, with some evidence for positive response. Larger studies are needed to better understand efficacy of checkpoint blockade in PML and factors that determine response.

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.

A Kidney Transplant Recipient With Fulminant Progressive Multifocal Leukoencephalopathy-Immune Reconstitution Inflammatory Syndrome: A Rare Clinical Outcome and Review of the Literature

Progressive multifocal leukoencephalopathy is a devastating disease affecting the central nervous system that may be seen in immunocompromised patients. We present a case of a kidney transplant recipient who received tacrolimus, mycophenolic acid, and prednisone and who developed motor deficits, altered cognition, and speech abnormalities, which culminated in a coma. The diagnosis was made by detecting John Cunningham polyomavirus DNA with polymerase chain reaction and observing characteristic findings on magnetic resonance imaging. Soon after immunosuppressive therapy was withdrawn, the patient's clinical status deteriorated due to immune reconstitution inflammatory syndrome, and prednisone was administered. Unfortunately, the patient died about 9 months after onset of symptoms. This case serves to illustrate the fulminant progression of progressive multifocal leukoencephalopathy and the possible complications that may arise when treating it.

CNS Infections in Immunoincompetent Patients : Neuroradiological and Clinical Features

In patients with immunodeficiency the pathogen spectrum of central nervous system (CNS) infections is broader and different from that of immunocompetent patients. Numerous opportunistic infections are characterized by a high prevalence of viral, bacterial and parasitic pathogens, and depend on the type of impaired immune defense, for example impaired T‑cell or monocyte function, monoclonal antibody treatment, and impaired granulocyte function. Neuroradiological features as well as laboratory findings are often different and versatile in comparison to immunocompetent individuals and pathognomonic imaging findings do not exist; however, knowledge of possible pathways of pathogens in the CNS and preferred tissue affection may help in narrowing down differential diagnoses. Therefore, knowledge of the type of patient and the performed immunomodulatory therapy is essential for the neuroradiological assessment and the differential diagnostic considerations. Moreover, parenchymal reactions in the sense of an immune reconstitution inflammatory syndrome (IRIS) can occur when immunocompetence is restored. This review focus on the most common pathologies in immunocompromised patients, and an overview of imaging features but also of pathology and clinical aspects is given. The synopsis of anamnestic information, clinical findings and structured analysis of the lesion pattern, its spread and short-term follow-up may increase the correct diagnostic classification; however, the gold standard is still determination of the pathogen in the cerebrospinal fluid (CSF), blood cultures or biopsies.

TB-IRIS pathogenesis and new strategies for intervention: Insights from related inflammatory disorders

In almost one in five HIV/tuberculosis (TB) co-infected patients, initiation of antiretroviral therapy (ART) is complicated by TB immune reconstitution inflammatory syndrome (TB-IRIS). Corticosteroids have been suggested for treatment of severe cases, however no therapy is currently licensed for TB-IRIS. Hence, there is a strong need for more specific therapeutics, and therefore, a better understanding of TB-IRIS pathogenesis. Immune reconstitution following ART is a precariously balanced functional restoration of adaptive immunity. In those patients predisposed to disease, an incomplete activation of the innate immune system leads to a hyper-inflammatory response that comprises partially overlapping innate, adaptive and effector arms, eventually leading to clinical symptoms. Interestingly, many of these pathological mechanisms are shared by related inflammatory disorders. We here describe therapeutic strategies that originate from these other disciplines and discuss their potential application in TB-IRIS. These new avenues of interventions range from final-phase treatment of symptoms to early-phase prevention of disease onset. In conclusion, we propose a novel approach for the discovery and development of therapeutics, based on an updated model of TB-IRIS pathogenesis. Further experimental studies validating the causal relationships in the proposed model could greatly contribute to providing a solid immunological basis for future clinical trials on TB-IRIS therapeutics.

Cost-effectiveness of Cladribine Tablets and fingolimod in the treatment of relapsing multiple sclerosis with high disease activity in Spain

OBJECTIVE

To estimate the cost-effectiveness of Cladribine Tablets in the treatment of relapsing multiple sclerosis (RMS) with high disease activity compared with fingolimod, from the perspective of the National Health System (NHS) in Spain.

METHODS

A Markov model was developed. The annual transition probabilities, were adjusted to patients with RMS with high disease activity. The effect of the treatments compared on the Expanded Disability Status Scale (EDSS) was modeled by hazard ratios for the confirmed progression of disability. The annual relapse rate and the probability of suffering adverse reactions were obtained from a meta-analysis and the literature. The derived costs were calculated from Spanish unit costs. The utilities were obtained from the CLARITY clinical trial and the literature. Deterministic and probabilistic sensitivity analyzes were performed.

RESULTS

Cladribine tablets was the dominant treatment: lower costs (-86,536 €) and more effective (+1.11 quality-adjusted life years - QALYs) compared to fingolimod. The probability that Cladribine Tablets was cost-effective compared to fingolimod ranged between 94.6% and 96.1% for willingness to pay from € 20,000 to € 30,000 per QALY gained.

CONCLUSIONS

Cladribine Tablets is a cost-effective treatment, compared to fingolimod, for the treatment of RMS with high disease activity.

EXPERT OPINION

According to the present study, compared to fingolimod, treatment with Cladribine Tablets of relapsing multiple sclerosis with high disease activity is an option that could generate savings for the Spanish National Health System, with a considerable gain in QALYs. Cladribine Tablets is considered cost-effective and dominant (less costs and more effectiveness) than fingolimod treatment option in this population.

Management of Advanced HIV Disease

Great progress has been made in caring for persons with human immunodeficiency virus. However, a significant proportion of individuals still present to care with advanced disease and a low CD4 count. Careful considerations for selection of antiretroviral therapy as well as close monitoring for opportunistic infections and immune reconstitution inflammatory syndrome are vitally important in providing care for such individuals.

The "milky way" galaxy of HIV-related central nervous system immune reaction syndromes

The landscape of central nervous system HIV infection is rapidly changing, leading to the recognition of a new constellation of overlapping syndromes and to a better insight for the elder ones. Among these, progressive multifocal leukoencephalopathy (PML) still poses several diagnostic and therapeutic challenges; nevertheless, recent developments in understanding PML in patients with multiple sclerosis may have benefitted HIV-positive patients suffering from PML too. We describe a peculiar case of PML-immune reconstitution inflammatory syndrome (IRIS) presenting a punctate pattern with "milky way" appearance on magnetic resonance imaging. Despite the fact that brain imaging and histopathology remain the mainstays for extricating through the expanding galaxy of HIV-related central nervous system dysimmune syndromes and although punctate pattern has been already well acknowledged as a suggestive finding of PML among patients on natalizumab, this radiological presentation is still poorly recognised in AIDS-related PML cases, leading to possible life-threatening diagnostic delays. This is also the first report about intravenous immunoglobulin treatment in AIDS-related PML-IRIS; the favourable clinical and radiological outcome of our case and the preliminary administrations of intravenous immunoglobulins in natalizumab-associated PML-IRIS from literature support probable benefits also among HIV-positive patients.

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

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

Diffuse large B cell lymphoma secondary to JC virus in progressive multifocal leukoencephalopathy

We present the case of a 43-year-old-man with a past medical history of HIV with recently initiated HAART and existing PML that presented with altered mental status. The initial diagnosis was deemed to be PML-IRIS; however, neuroimaging brought into question this diagnosis. Flow cytometry performed from the cerebrospinal fluid revealed diffuse large B cell lymphoma. JC virus may act in an oncogenic role similarly to EBV and predispose to CNS lymphomas. Patients with PML caused by JC virus may develop secondary malignancies.

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

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

Treatment of natalizumab-associated PML with filgrastim

Objective

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

Methods

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

Results

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

Interpretation

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

The spectrum of progressive multifocal leukoencephalopathy: a practical approach

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

Global HIV neurology: a comprehensive review

: Neurological conditions associated with HIV remain major contributors to morbidity and mortality and are increasingly recognized in the aging population on long-standing combination antiretroviral therapy (cART). Importantly, growing evidence shows that the central nervous system (CNS) may serve as a reservoir for viral replication, which has major implications for HIV eradication strategies. Although there has been major progress in the last decade in our understanding of the pathogenesis, burden, and impact of neurological conditions associated with HIV infection, significant scientific gaps remain. In many resource-limited settings, antiretrovirals considered second or third line in the United States, which carry substantial neurotoxicity, remain mainstays of treatment, and patients continue to present with severe immunosuppression and CNS opportunistic infections. Despite this, increased global access to cART has coincided with an aging HIV-positive population with cognitive sequelae, cerebrovascular disease, and peripheral neuropathy. Further neurological research in low-income and middle-income countries (LMICs) is needed to address the burden of neurological complications in HIV-positive patients, particularly regarding CNS viral reservoirs and their effects on eradication.

HIV-associated opportunistic CNS infections: pathophysiology, diagnosis and treatment

Nearly 30 years after the advent of antiretroviral therapy (ART), CNS opportunistic infections remain a major cause of morbidity and mortality in HIV-positive individuals. Unknown HIV-positive disease status, antiretroviral drug resistance, poor drug compliance, and recreational drug abuse are factors that continue to influence the morbidity and mortality of infections. The clinical and radiographic pattern of CNS opportunistic infections is unique in the setting of HIV infection: opportunistic infections in HIV-positive patients often have characteristic clinical and radiological presentations that can differ from the presentation of opportunistic infections in immunocompetent patients and are often sufficient to establish the diagnosis. ART in the setting of these opportunistic infections can lead to a paradoxical worsening caused by an immune reconstitution inflammatory syndrome (IRIS). In this Review, we discuss several of the most common CNS opportunistic infections: cerebral toxoplasmosis, progressive multifocal leukoencephalopathy (PML), tuberculous meningitis, cryptococcal meningitis and cytomegalovirus infection, with an emphasis on clinical pearls, pathological findings, MRI findings and treatment. Moreover, we discuss the risk factors, pathophysiology and management of IRIS. We also summarize the challenges that remain in management of CNS opportunistic infections, which includes the lack of phase II and III clinical trials, absence of antimicrobials for infections such as PML, and controversy regarding the use of corticosteroids for treatment of IRIS.

Understanding mechanisms underlying the pathology of immune reconstitution inflammatory syndrome (IRIS) by using animal models

Purpose of Review

Despite the increasing number of clinical reports on immune reconstitution inflammatory syndrome (IRIS), mechanistic understanding of IRIS is still largely limited. The main focus of this review is to summarize animal studies, which were performed to better understand the cellular and molecular mechanisms underlying the pathology of IRIS.

Recent Findings

Three IRIS animal models have been reported. They are Mycobacterial IRIS (M-IRIS), cryptococcal IRIS (C-IRIS) and Pneumocystis-IRIS. M-IRIS animal model suggested that, rather than lymphopenia itself, the failure to clear the pathogen by T cells results in excessive priming of the innate immune system. If this happens before T cell reconstitution, hosts likely suffer IRIS upon T cell reconstitution. Interestingly, T cells specific to self-antigens, not only pathogen-specific, could drive IRIS as well.

Summary

The mechanism to develop IRIS is quite complicated, including multiple layers of host immune responses; the innate immune system that detects pathogens and prime host immunity, and the adaptive immune system that is reconstituted but hyper-activated particularly through CD4⁺ T cells. Animal models of IRIS, although there are still small numbers of studies available, have already provided significant insights on the mechanistic understanding of IRIS.

Neurological syndromes driven by postinfectious processes or unrecognized persistent infections

PURPOSE OF REVIEW

The immune system serves a critical role in protecting the host against various pathogens. However, under circumstances, once triggered by the infectious process, it may be detrimental to the host. This may be as a result of nonspecific immune activation or due to a targeted immune response to a specific host antigen. In this opinion piece, we discuss the underlying mechanisms that lead to such an inflammatory or autoimmune syndrome affecting the nervous system. We examine these hypotheses in the context of recent emerging infections to provide mechanistic insight into the clinical manifestations and rationale for immunomodulatory therapy.

RECENT FINDINGS

Some pathogens endure longer than previously thought. Persistent infections may continue to drive immune responses resulting in chronic inflammation or development of autoimmune processes, resulting in damage to the nervous system. Patients with genetic susceptibilities in immune regulation may be particularly vulnerable to pathogen driven autoimmune responses.

SUMMARY

The presence of prolonged pathogens may result in chronic immune stimulations that drives immune-mediated neurologic complications. Understanding the burden and mechanisms of these processes is challenging but important.

[Two patients with progressive multifocal leukoencephalopathy with immune response against JC virus showing good long-term outcome by combination therapy of mefloquine, mirtazapine, and risperidone]

Patient 1 was a 59-year-old woman receiving prednisolone for idiopathic hypereosinophilia. Brain MRI of patient 1 disclosed slight gadolinium enhancement at lesions, indicating inflammation. Patient 2 was a 32-year-old woman with systemic lupus erythematosus under immunosuppressive therapy. Brain biopsy of patient 2 showed balanced infiltration of CD8+ and CD4+ T lymphocytes at the sites of lesions. Both subjects were diagnosed as having progressive multifocal leukoencephalopathy (PML) shortly after the onset of neurological symptoms and were treated with a combination of mefloquine, mirtazapine, and risperidone. Both patients remain alive with improved neurological symptoms even after long-term follow-up (24 months in patient 1 and 45 months in patient 2). Although the prognosis of PML is very poor, our findings suggest that pharmacotherapy may be effective for patients with well-controlled immune reactions against the JC virus.

Progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is a relatively common complication of HIV disease. In this chapter changes to the epidemiology are discussed along with an update in its pathogenesis and treatment. Immune reconstitution inflammatory syndrome is increasingly frequent in PML; accordingly management strategies and prognosis are detailed.

Global developments in HIV neurology

Neurologic conditions associated with HIV remain major contributors to morbidity and mortality, and are increasingly recognized in the aging population on long-standing combination antiretroviral therapy (cART). Importantly, growing evidence suggests that the central nervous system (CNS) serves as a reservoir for viral replication with major implications for human immunodeficiency virus (HIV) eradication strategies. Though there has been major progress in the last decade in our understanding of the pathogenesis, burden, and impact of HIV-associated neurologic conditions, significant scientific gaps remain. In many low-income settings, second- and third-line cART regimens that carry substantial neurotoxicity remain treatment mainstays. Further, patients continue to present severely immunosuppressed with CNS opportunistic infections. Public health efforts should emphasize improvements in access and optimizing treatment of HIV-positive patients, specifically in resource-limited settings, to reduce the risk of neurologic sequelae.

CNS immune reconstitution inflammatory syndrome

Immune reconstitution inflammatory syndrome (IRIS) describes a syndrome of aberrant reconstituted immunity, often in association with HIV infection, beginning with a normalization of CD4+ T-cell counts resulting in a dysregulated immune response against an infecting opportunistic pathogen and the host. In this chapter, we discuss the unique nature of IRIS when present in the central nervous system (CNS IRIS) and the changes experienced with each host pathogen and its unique influence on the immune system. Consensus on the mechanism of action of the immune system in IRIS pathology is less clear and multiple theories have been proposed. Here we explore the early history of the term IRIS, proposed mechanisms and animal models, as well as common CNS pathogens associated with IRIS, and management strategies.

Isolated posterior fossa involvement of progressive multifocal leucoencephalopathy in HIV: A case series with review of the literature

Progressive multifocal leucoencephalopathy (PML) is a progressive demyelinating condition resulting from infection with the John Cunningham virus and precipitated by immunocompromised states. The HIV pandemic, especially in sub-Saharan Africa, has resulted in an increase in the number of patients presenting with PML. Imaging plays an important role in diagnosis and the distribution of the disease is predominantly supratentorial. Isolated posterior fossa involvement is a rare finding with very few cases described in the literature. We present the largest case series of patients described in the literature, with isolated posterior fossa involvement of PML, in HIV-positive patients.

Ventriculoperitoneal shunt insertion for hydrocephalus in human immunodeficiency virus-infected adults: a systematic review and meta-analysis protocol

BACKGROUND

Hydrocephalus is a recognised complication of human immunodeficiency virus (HIV)-related opportunistic infections. Symptomatic raised cerebrospinal fluid pressure can be treated with ventriculoperitoneal shunt insertion (VPS). In HIV-infected patients however, there is a concern that VPS might be associated with unacceptably high rates of mortality. We aim to systematically review and appraise published literature to determine reported outcomes and identify predictors of outcome following VPS in relevant subgroups of HIV-infected adults.

METHODS

The following electronic databases will be searched: The Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (PubMed), EMBASE, CINAHL (EBSCOhost), LILACS (BIREME), Research Registry ( www.researchregistry.com ), the metaRegister of Controlled Trials (mRCT) ( www.controlled-trials.com ), ClinicalTrials.gov ( www.clinicaltrials.gov ) and OpenSIGLE database. Any randomised studies, cohort studies, case-control studies, interrupted time series or sequential case series reporting survival following VPS in HIV-infected individuals will be included. If high-quality homogenous studies exist, meta-analysis will be conducted to determine 1-, 6- and 12-month mortality with comparison made between underlying aetiologies of hydrocephalus.

DISCUSSION AND CONCLUSION

This study will generate a comprehensive review of VPS in HIV-infected patients for publication. The primary outcome of meta-analysis is 12-month survival. If only low-quality, heterogeneous studies are available, this study will demonstrate this deficiency and will be of value in justifying and aiding the design of future studies.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42016052239.

Interventions for Neurocognitive Dysfunction

PURPOSE OF REVIEW

This study aimed to evaluate current barriers to HIV cure strategies and interventions for neurocognitive dysfunction with a particular focus on recent advancements over the last 3 years.

RECENT FINDINGS

Optimal anti-retroviral therapy (ART) poses challenges to minimise neurotoxicity, whilst ensuring blood-brain barrier penetration and minimising the risk of cerebrovascular disease. CSF biomarkers, BCL11B and neurofilament light chain may be implicated with a neuroinflammatory cascade leading to cognitive impairment. Diagnostic imaging with diffusion tensor imaging and resting-state fMRI show promise in future diagnosis and monitoring of HAND. The introduction of ART has resulted in a dramatic decline in HIV-associated dementia. Despite this reduction, milder forms of HIV-associated neurocognitive disorder (HAND) are still prevalent and are clinically significant. The central nervous system (CNS) has been recognised as a probable reservoir and sanctuary for HIV, representing a significant barrier to management interventions.

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

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

Long-term safety evaluation of natalizumab for the treatment of multiple sclerosis

Natalizumab is a humanized monoclonal antibody highly effective in relapsing-remitting multiple sclerosis (MS). Important concerns about its safety have been pointed out mainly because of the risk of progressive multifocal leukoencephalopathy (PML), caused by the opportunistic John-Cunningham virus (JCV). Areas covered: This review analyzes all the safety aspects related to the use and safety of natalizumab in MS patients. Other than PML, post-marketing, safety red-flags have been reported, as liver or haematological serious adverse events. Pregnancy evidences will be pointed out. The risk of PML depends on: concomitant or previous immunosuppression, exposure duration, anti-JCV antibody level. In natalizumab-related PML the average survival is 77%; prognostic features and information for the earliest identification of PML have been identified to maximally reduce its incidence, mortality and morbidity. Expert opinion: Natalizumab is a highly effective drug for MS patients but its safety issues represent a relevant limitation and impose strict clinical surveillance of treated patients. Some post-marketing safety red-flags have been pointed out, with higher attention to severe liver failures and limphoma cases. If PML and its consequences are considered the most relevant issues, a continuous surveillance must be maintained also regarding other possible SAEs like liver diseases and malignancies.

Immune Reconstitution Inflammatory Syndrome Unmasking or Worsening AIDS-Related Progressive Multifocal Leukoencephalopathy: A Literature Review

Incidence of progressive multifocal leukoencephalopathy (PML) in HIV-infected patients has declined in the combined antiretroviral therapy (cART) era although a growing number of acquired immunodeficiency syndrome (AIDS)-related PML-immune reconstitution inflammatory syndromes (PML-IRIS) have been published during the same period. Therapeutic management of PML-IRIS is not consensual and mainly relies on corticosteroids. Our main aim was, in addition to provide a thoughtful analysis of published PML-IRIS cases, to assess the benefit of corticosteroids in the management of PML-IRIS, focusing on confirmed cases. We performed a literature review of the 46 confirmed cases of PML-IRIS cases occurring in HIV-infected patients from 1998 to September 2016 (21 unmasking and 25 paradoxical PML-IRIS). AIDS-related PML-IRIS patients were mostly men (sex ratio 4/1) with a median age of 40.5 years (range 12-66). Median CD4 T cell count before cART and at PML-IRIS onset was 45/μl (0-301) and 101/μl (20-610), respectively. After cART initiation, PML-IRIS occurred within a median timescale of 38 days (18-120). Clinical signs were motor deficits (69%), speech disorders (36%), cognitive disorders (33%), cerebellar ataxia (28%), and visual disturbances (23%). Brain MRI revealed hyperintense areas on T2-weighted sequences and FLAIR images (76%) and suggestive contrast enhancement (87%). PCR for John Cunningham virus (JCV) in cerebrospinal fluid (CSF) was positive in only 84% of cases; however, when performed, brain biopsy confirmed diagnosis of PML in 90% of cases and demonstrated histological signs of IRIS in 95% of cases. Clinical worsening related to PML-IRIS and leading to death was observed in 28% of cases. Corticosteroids were prescribed in 63% of cases and maraviroc in one case. Statistical analysis failed to demonstrate significant benefit from steroid treatment, despite spectacular improvement in certain cases. Diagnosis of PML-IRIS should be considered in HIV-infected patients with worsening neurological symptoms after initiation or resumption of effective cART, independently of CD4 cell count prior to cART. If PCR for JCV is negative in CSF, brain biopsy should be discussed. Only large multicentric randomized trials could potentially demonstrate the possible efficacy of corticosteroids and/or CCR5 antagonists in the management of PML-IRIS.

Imaging spectrum of central nervous system complications of hematopoietic stem cell and solid organ transplantation

Neurologic complications are common after hematopoietic stem cell transplantation (HSCT) and solid organ transplantation (SOT) and affect 30-60% of transplant recipients. The aim of this article is to provide a practical imaging approach based on the timeline and etiology of CNS abnormalities, and neurologic complications related to transplantation of specific organs. The lesions will be classified based upon the interval from HSCT procedure: pre-engraftment period <30 days, early post-engraftment period 30-100 days, late post-engraftment period >100 days, and the interval from SOT procedure: postoperative phase 1-4 weeks, early posttransplant syndromes 1-6 months, late posttransplant syndromes >6 months. Further differentiation will be based on etiology: infections, drug toxicity, metabolic derangements, cerebrovascular complications, and posttransplantation malignancies. In addition, differentiation will be based on complications specific to the type of transplantation: allogeneic and autologous hematopoietic stem cells (HSC), heart, lung, kidney, pancreas, and liver. Thus, in this article we emphasize the strategic role of neuroradiology in the diagnosis and response to treatment by utilizing a methodical approach in the work up of patients with neurologic complications after transplantation.

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

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

Treatment-Related Progressive Multifocal Leukoencephalopathy in Multiple Sclerosis: A Comprehensive Review of Current Evidence and Future Needs

Progressive multifocal leukoencephalopathy (PML) is a rare opportunistic infection of the central nervous system caused by the John Cunningham virus (JCV) that has been associated with therapeutic immunosuppression in patients with multiple sclerosis (MS). So far, more than 600 cases of PML have been reported in association with natalizumab administration. There have also been confirmed cases of PML in individuals who received fingolimod and dimethyl fumarate without previous natalizumab treatment. The new licensed disease-modifying therapies for MS carry the risk of immunosuppressant and so of JCV reactivation. Various factors have been identified with increased risk of developing PML, including a positive JCV serology, natalizumab administration for >2 years, and prior use of immunosuppressive agents. Clinicians can employ such tools for patients' risk stratification, but the incidence of PML among patients receiving natalizumab therapy has not changed. In this review we outline the current state of understanding of PML pathogenesis and patients' risk stratification. The landscape of MS is dramatically changing and knowledge of the side effects of the licensed therapies is imperative to enable optimal decision making.

Progressive Multifocal Leukoencephalopathy in a Multiple Sclerosis Patient Diagnosed after Switching from Natalizumab to Fingolimod

Background. Natalizumab- (NTZ-) associated progressive multifocal leukoencephalopathy (PML) is a severe and often disabling infectious central nervous system disease that can become evident in multiple sclerosis (MS) patients after NTZ discontinuation. Recently, novel diagnostic biomarkers for the assessment of PML risk in NTZ treated MS patients such as the anti-JC virus antibody index have been reported, and the clinical relevance of milky-way lesions detectable by MRI has been discussed. Case Presentation and Conclusion. We report a MS patient in whom PML was highly suspected solely based on MRI findings after switching from NTZ to fingolimod despite repeatedly negative (ultrasensitive) polymerase chain reaction (PCR) testing for JC virus DNA in cerebrospinal fluid. The PML diagnosis was histopathologically confirmed by brain biopsy. The occurrence of an immune reconstitution inflammatory syndrome (IRIS) during fingolimod therapy, elevated measures of JCV antibody indices, and the relevance of milky-way-like lesions detectable by (7 T) MRI are discussed.

Successful pregnancy after natalizumab-associated progressive multifocal leukoencephalopathy in a patient with multiple sclerosis

We report the case of a post-progressive multifocal leukoencephalopathy (PML), multiple sclerosis (MS) patient with an uncomplicated pregnancy and delivery. A 28-year-old woman on natalizumab (total of 49 infusions) was diagnosed with PML due to typical magnetic resonance imaging (MRI) and clinical presentation. John Cunningham virus (JCV) was detected in the cerebrospinal fluid (CSF) during the immune reconstitution inflammatory syndrome (IRIS). Nine months after PML onset, JCV negativity in the CSF was observed. MS was stabilised with dimethyl fumarate (DMF), and 18 months later, a desired pregnancy was reported, resulting in the birth of a healthy boy. Our report gives new hope regarding family planning for post-PML patients.