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.

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

OBJECTIVE: In the present study, we analyzed the inflammatory profiles of brain tissues obtained from patients with progressive multifocal leukoencephalopathy (PML) due to John Cunningham (JC) virus infection to identify potential prognostic factors. METHODS: The study included seven patients (two men, five women) who had been pathologically diagnosed with PML, and all of whom were HIV negative. Fixed brain samples were analyzed via hematoxylin and eosin (HE) staining and Klüver-Barrera (KB) staining. We then performed immunohistochemistry (IHC) specific to JC virus capsid proteins (VP1 and VP2/3) and lymphocyte surface markers (CD4, CD8, CD138, and PD-1). RESULTS: The mean age at onset was 53.4, while the mean duration until biopsy/autopsy was 4.7 months. Four patients were included in the good prognosis (GP) group, while three were included in the poor prognosis (PP) group. Pathological analysis revealed a significantly larger number of CD4-positive T-cell infiltrations (P = .029) in the GP group, along with a preserved CD4:CD8 ratio. Larger numbers of CD138-positive plasma cells were also observed in the GP group (P = .029) than in the PP group. Linear regression analyses revealed a significant association between the numbers of CD138-positive plasma cells and PD-1-positive cells (R2 = 0.80). CONCLUSIONS: Viral loads in the cerebrospinal fluid, a controlled inflammatory response mediated by CD4- and CD8-positive T cells, and plasma cells are associated with PML prognosis. Our findings further indicate that regulatory plasma cells may regulate inflammatory T-cell activity via a PD-1/PD-L1 immuno-checkpoint pathway, thereby protecting the uninfected brain from excessive immune-mediated damage during an active JC virus infection.

Progressive multifocal leukoencephalopathy in the absence of immunosuppression.

A 69-year-old woman presented with a cortical hand syndrome progressing over several weeks. MRI brain showed characteristic appearances of progressive multifocal leukoencephalopathy (PML), confirmed by detection of the JC virus in CSF, despite the absence of any evidence of immunosuppression. Treatment with mirtazapine, mefloquine and cidofovir did not affect the progression of the disease, which was fatal within 7 months of presentation. This report adds to the small case literature that suggests that PML can occur in immunocompetent people, albeit extremely rarely.

Refractory epilepsy following natalizumab associated PML.

Natalizumab treatment of multiple sclerosis (MS) is associated with a risk of developing progressive multifocal leukoencephalopathy (PML), a rare opportunistic viral demyelinating disease caused by reactivation of John Cunningham virus (JCV). Herein, we report a case of a 40-year-old woman who developed refractory temporal lobe epilepsy; one year after recovery form Natalizumab-induced PML. Localisation related epilepsy, which may be refractory in nature, as in this case report, is a potential chronic disabling complication of PML. Epilepsy in this context, likely reflects grey matter involvement, which may then act as cortical epileptogenic zone.

Posterior fossa progressive multifocal leukoencephalopathy: first presentation of an unknown autoimmune disease.

We present a case of a 57-year-old man who presented with progressive cerebellar dysarthria and cerebellar ataxia. Additional investigations confirmed the diagnosis of progressive multifocal leukoencephalopathy (PML) in the posterior fossa. This is a demyelinating disease of the central nervous system, caused by an opportunistic infection with John Cunningham virus. PML has previously been considered a lethal condition, but because of careful monitoring of patients with HIV and of patients using immunosuppressive drugs it is discovered in earlier stages and prognosis can be improved. Our patient had no known immune-compromising state, but further work-up revealed that the PML was most likely the first presentation of a previous untreated autoimmune disorder: sarcoidosis.

Progressive multifocal leukoencephalopathy - immune reconstitution inflammatory syndrome (PML-IRIS) in liver transplant recipient.

65-year-old liver transplant recipient presented with progressive neurologic dysfunction. CSF analysis revealed high JC virus load and MRI findings suggested the diagnosis of progressive multifocal leukoencephalopathy (PML). Cidofovir and mirtazapine were initiated and patient's regular immunosuppressants were reduced. Subsequently patient developed left sided hemiplegia, drowsiness and severe neglect syndrome. MRI revealed enlargement of PML lesions with contrast enhancement and worsening of oedema, consistent with immune reconstitution inflammatory syndrome (IRIS). Steroids were initiated and 3 weeks later patient showed moderate neurologic improvement. PML-IRIS after solid organ transplantation is rarely detected and to the best of our knowledge, this is the first reported case of PML-IRIS in a liver transplant recipient.

Post-cART progressive multifocal leukoencephalopathy era in a Brazilian center.

Progressive multifocal leukoencephalopathy (PML) is lytic infection of oligodendrocytes caused by JC virus (JCV). While PML incidence in developing countries has decreased after the introduction of combination antiretroviral therapy (cART), data in developing countries is scarce and limited to few cohorts. We described the epidemiological and clinical profile of a group of Brazilian HIV infected patients with PML in the cART era. A total of 27 patients were included in the study. The median age at PML onset was 42years (range: 27-67years) and 18 (66.7%) were men. The median CD4+ T cell count at the time of diagnosis was 67cells/mm3 and the median HIV viral load was 27,000copies/ml. Motor deficits were the most common early manifestations (44%). Seizures occurred in 37% of the patients and 9 (33.3%) had PML associated with immune reconstitution inflammatory syndrome (IRIS). Mortality was 33% and lower age at PML onset was associated with survival (p: 0.013). Our results are in accordance with previous published series of PML cases. Factors such as genetic background, regional JCV subtype differences, death from other diseases and underdiagnosis may explain the low prevalence of reported PML cases in developing countries.

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

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

Progressive multifocal leukoencephalopathy and rheumatoid arthritis treatments.

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system due to reactivation of the JC virus (JCV). PML is extremely uncommon despite the high prevalence of the virus in the general population. No specific treatment is available, and the prognosis is bleak. The diagnosis is based on brain imaging findings, detection of the JCV genome in cerebrospinal fluid samples and, in some cases, histological studies of the brain lesions. The pathophysiological mechanisms that drive the development of PML are incompletely understood. However, a consistent feature is the presence of a predisposing factor, most notably immunosuppression. The risk of developing PML varies with the underlying disease (e.g., HIV infection or autoimmune disease) and with the drugs used to treat them. Biologics have been ranked according to the risk of PML during their use. Natalizumab, a monoclonal antibody given to treat multiple sclerosis, is among the drugs associated with a high risk of PML. Patients given natalizumab are now closely monitored based on anti-JCV antibody titers and index values. In rheumatology, the expanding use of biologics has led to an increase in cases of PML, with rituximab being associated with the highest risk. Given the absence of specific recommendations, exhaustive registries and postmarketing observational studies are urgently needed to gauge the risk of PML according to the underlying disease and drug treatments, with the goal of defining optimal monitoring protocols.

Natalizumab-Related Progressive Multifocal Leukoencephalopathy in Multiple Sclerosis: Findings from an Italian Independent Registry.

BACKGROUND: The monoclonal antibody natalizumab (NTZ) is a highly effective treatment for patients with multiple sclerosis (MS). However, this drug is associated with increased risk of developing Progressive Multifocal Leukoencephalopathy (PML), an opportunistic infection of central nervous system (CNS) caused by the John Cunningham polyomavirus (JCV). OBJECTIVE: To describe the 12-month clinical course of 39 patients with MS (28 women, 11 men) who developed NTZ-related PML after a mean exposure of 39 infusions. METHODS: An Italian independent collaborative repository initiative collected and analyzed socio-demographic, clinical, magnetic resonance imaging (MRI) data and number of JCV-DNA copies detected on cerebrospinal fluid (CSF) samples of patients diagnosed as affected by NTZ-related PML. The evolution of disability, measured by the Expanded Disability Status Scale, was assessed at NTZ start, at PML diagnosis and after 2, 6 and 12 months from PML diagnosis. The effect of clinical and paraclinical characteristics at PML diagnosis on the final outcome was also investigated. RESULTS: Ten patients (25.6%) were diagnosed before 24 NTZ infusions. In six cases (15.4%) the PML suspect was made on the basis of highly suggestive MRI findings in absence of any detectable change of clinical conditions (asymptomatic PML). In patients with symptomatic PML, the diagnosis was quicker for those who presented with cognitive symptoms (n = 12) rather than for those with other neurological pictures (n = 21) (p = 0.003). Three patients (7.7%) died during the 12-month observation period, resulting in a survival rate of 92.3%. Asymptomatic PML, more localized brain involvement and gadolinium-enhancement detected at MRI, as well as lower viral load were associated with a better disability outcome (p-values<0.01). CONCLUSION: Our findings support that early PML diagnosis, limited CNS involvement and initial signs of immune restoration are associated with a better outcome and higher survival rate, and confirm the utility of MRI as a surveillance tool for NTZ-treated patients.

Functional course of Progressive Multifocal Leukoencephalopathy.

Progressive multifocal leukoencephalopathy is a demyelinating disease of the central nervous system, characterized by aggressive deterioration of white matter pathways throughout the subcortical brain parenchyma. This disease leads the patient to a total dependence in all activities of daily (ADLs) living in few months. The literature on rehabilitation of progressive multifocal leukoencephalopathy is scanty and, at present, it is unknown whether rehabilitation may modify the course of disability in this disease. This paper describes the functional course of a patients with progressive multifocal leukoencephalopathy who incurred in a severe functional impairment of ADLs after an unintentional fall and prolonged bed rest. The multidisciplinary in-hospital rehabilitation program and integrated homecare approach allowed the patient to improve her functional capacities and go on with living at home.

Hyperintense cortical signal on magnetic resonance imaging reflects focal leukocortical encephalitis and seizure risk in progressive multifocal leukoencephalopathy.

OBJECTIVE: To determine the frequency of hyperintense cortical signal (HCS) on T1-weighted precontrast magnetic resonance (MR) images in progressive multifocal leukoencephalopathy (PML) patients, its association with seizure risk and immune reconstitution inflammatory syndrome (IRIS), and its pathologic correlate. METHODS: We reviewed clinical data including seizure history, presence of IRIS, and MR imaging scans from PML patients evaluated at our institution between 2003 and 2012. Cases that were diagnosed either using cerebrospinal fluid JC virus (JCV) polymerase chain reaction, brain biopsy, or autopsy, and who had MR images available were included in the analysis (n=49). We characterized pathologic findings in areas of the brain that displayed HCS in 2 patients and compared them with isointense cortex in the same individuals. RESULTS: Of 49 patients, 17 (34.7%) had seizures and 30 (61.2%) had HCS adjacent to subcortical PML lesions on MR images. Of the 17 PML patients with seizures, 15 (88.2%) had HCS compared with 15 of 32 (46.9%) patients without seizures (p=0.006). HCS was associated with seizure development with a relative risk of 4.75 (95% confidence interval=1.2-18.5, p=0.006). Of the 20 patients with IRIS, 16 (80.0%) had HCS compared with 14 of 29 (49.3%) patients without IRIS (p=0.04). On histological examination, HCS areas were associated with striking JCV-associated demyelination of cortical and subcortical U fibers, significant macrophage infiltration, and a pronounced reactive gliosis in the deep cortical layers. INTERPRETATION: Seizures are a frequent complication in PML. HCS is associated with seizures and IRIS, and correlates histologically with JCV focal leukocortical encephalitis.

Hyperperfusion in progressive multifocal leukoencephalopathy is associated with disease progression and absence of immune reconstitution inflammatory syndrome.

We sought to characterize perfusion patterns of progressive multifocal leukoencephalopathy lesions by arterial spin labelling perfusion magnetic resonance imaging and to analyse their association with immune reconstitution inflammatory syndrome, and survival. A total of 22 patients with progressive multifocal leukoencephalopathy underwent a clinical evaluation and magnetic resonance imaging of the brain within 190 days of symptom onset. The presence of immune reconstitution inflammatory syndrome was determined based on clinical and laboratory criteria. Perfusion within progressive multifocal leukoencephalopathy lesions was determined by arterial spin labelling magnetic resonance imaging. We observed intense hyperperfusion within and at the edge of progressive multifocal leukoencephalopathy lesions in a subset of subjects. This hyperperfusion was quantified by measuring the fraction of lesion volume showing perfusion in excess of twice normal appearing grey matter. Hyperperfused lesion fraction was significantly greater in progressive multifocal leukoencephalopathy progressors than in survivors (12.8% versus 3.4% P = 0.02) corresponding to a relative risk of progression for individuals with a hyperperfused lesion fraction ≥ 4.0% of 9.1 (95% confidence interval of 1.4-59.5). The presence of hyperperfusion was inversely related to the occurrence of immune reconstitution inflammatory syndrome at the time of scan (P = 0.03). Indeed, within 3 months after symptom onset, hyperperfusion had a positive predictive value of 88% for absence of immune reconstitution inflammatory syndrome. Arterial spin labelling magnetic resonance imaging recognized regions of elevated perfusion within lesions of progressive multifocal leukoencephalopathy. These regions might represent virologically active areas operating in the absence of an effective adaptive immune response and correspond with a worse prognosis.

Clinically silent PML and prolonged immune reconstitution inflammatory syndrome in a patient with multiple sclerosis treated with natalizumab.

We report the case of a woman with natalizumab-treated multiple sclerosis (MS) and clinically silent progressive multifocal leukoencephalopathy (PML) with an unusually long preclinical phase, followed by acute symptoms due to development of immune reconstitution inflammatory syndrome (IRIS). Furthermore, the course of the IRIS was prolonged and continued to progress even five months after natalizumab treatment was ceased. This case shows that PML and IRIS can have a considerably variable course in natalizumab-treated MS patients and underlines the need for PML screening in JC virus antibody-positive patients in order to detect clinically silent cases.