Inflammatory infratentorial progressive multifocal leukoencephalopathy in a patient with rheumatoid arthritis

Microglia in antiviral immunity of the brain and spinal cord

Viral infections of the central nervous system (CNS) are a significant cause of neurological impairment and mortality worldwide. As tissue resident macrophages, microglia are critical initial responders to CNS viral infection. Microglia seem to coordinate brain-wide antiviral responses of both brain resident cells and infiltrating immune cells. This review discusses how microglia may promote this antiviral response at a molecular level, from potential mechanisms of virus recognition to downstream cytokine responses and interaction with antiviral T cells. Recent advancements in genetic tools to specifically target microglia in vivo promise to further our understanding about the precise mechanistic role of microglia in CNS infection.

Progressive multifocal leukoencephalopathy in a patient with systemic sclerosis treated with methotrexate: A case report and literature review

Reactivation of viruses occurs in autoimmune disorders in the setting of certain immunosuppressive drugs. We describe a 54-year-old female with systemic sclerosis and extensive cutaneous calcinosis who had been treated with methotrexate for 18 months and presented with headache and neurological deficits. She was diagnosed with progressive multifocal leukoencephalopathy, a rare disease caused by JC virus. Methotrexate was discontinued and mirtazapine plus mefloquine were added. The patient showed a slow recovery and five years later she had complete resolution of progressive multifocal leukoencephalopathy clinical manifestations. Calcinosis had a limited response to various agents and severely affected daily activities of the patient. This case report, highlights the importance of clinical suspicion for progressive multifocal leukoencephalopathy in every patient with immune-mediated disease, even on weak immunosuppressant, who presents with central nervous system manifestations and also the unmet therapeutic need for systemic sclerosis-associated calcinosis.

Progressive Multifocal Leukoencephalopathy during Tocilizumab Treatment for Rheumatoid Arthritis

A 61-year-old woman was diagnosed with rheumatoid arthritis 12 years ago and received multiple treatment regimens before achieving symptomatic stability with methotrexate plus tocilizumab, a humanized monoclonal antibody against the IL-6 receptor, about 2 years prior to the current presentation. Sixteen months after tocilizumab initiation, she exhibited dysarthria and disorientation; five months later, she was hospitalized with movement difficulties. Her neurological symptoms deteriorated thereafter, accompanied by enlarged cerebral white matter lesions on magnetic resonance imaging. A biopsy of the right frontal lesion confirmed progressive multifocal leukoencephalopathy (PML). While several therapeutic monoclonal antibodies have been linked to PML, this is the first case associated with tocilizumab.

Drug-associated progressive multifocal leukoencephalopathy: a clinical, radiological, and cerebrospinal fluid analysis of 326 cases

The implementation of a variety of immunosuppressive therapies has made drug-associated progressive multifocal leukoencephalopathy (PML) an increasingly prevalent clinical entity. The purpose of this study was to investigate its diagnostic characteristics and to determine whether differences herein exist between the multiple sclerosis (MS), neoplasm, post-transplantation, and autoimmune disease subgroups. Reports of possible, probable, and definite PML according to the current diagnostic criteria were obtained by a systematic search of PubMed and the Dutch pharmacovigilance database. Demographic, epidemiologic, clinical, radiological, cerebrospinal fluid (CSF), and histopathological features were extracted from each report and differences were compared between the disease categories. In the 326 identified reports, PML onset occurred on average 29.5 months after drug introduction, varying from 14.2 to 37.8 months in the neoplasm and MS subgroups, respectively. The most common overall symptoms were motor weakness (48.6 %), cognitive deficits (43.2 %), dysarthria (26.3 %), and ataxia (24.1 %). The former two also constituted the most prevalent manifestations in each subgroup. Lesions were more often localized supratentorially (87.7 %) than infratentorially (27.4 %), especially in the frontal (64.1 %) and parietal lobes (46.6 %), and revealed enhancement in 27.6 % of cases, particularly in the MS (42.9 %) subgroup. Positive JC virus results in the first CSF sample were obtained in 63.5 %, while conversion after one or more negative outcomes occurred in 13.7 % of cases. 52.2 % of patients died, ranging from 12.0 to 83.3 % in the MS and neoplasm subgroups, respectively. In conclusion, despite the heterogeneous nature of the underlying diseases, motor weakness and cognitive changes were the two most common manifestations of drug-associated PML in all subgroups. The frontal and parietal lobes invariably constituted the predilection sites of drug-related PML lesions.

Neurological immune reconstitution inflammatory response: riding the tide of immune recovery

PURPOSE OF REVIEW

This manuscript reviews current reports about clinical aspects of immune reconstitution inflammatory syndrome (IRIS), with a particular emphasis on IRIS in the setting of progressive multifocal leukoencephalopathy (PML) and to a lesser extent on cryptococcal meningitis and HIV.

RECENT FINDINGS

PML prognosis has been radically improved, as it has become possible to provide immune reconstitution, although some remaining morbidity and mortality results from excess inflammation. Similar pathologic responses are seen less often, but remain clinically important in cryptococcal meningitis, and HIV. Early diagnosis and active management of PML results in optimal outcomes with survival of 75% or higher in multiple recent series. These finding apply both to natalizumab and HIV-associated PML. Cryptococcal meningitis is frequently complicated by IRIS, and early treatment with antifungal therapy preceding HIV therapy provides optimal outcomes. HIV IRIS is reduced by early therapy, which is now recommended, but even on therapy, chronic dysregulated immune responses may play important roles in ongoing HIV-associated neurocognitive disease (HAND), which is common, as well as rare but more dramatic subacute encephalopathies.

SUMMARY

The clinician must actively monitor and treat both opportunistic infection and the inflammatory response that is essential to recovery but may itself augment disease and injury.

Heterogeneous imaging characteristics of JC virus granule cell neuronopathy (GCN): a case series and review of the literature

Granule cell neuronopathy (GCN) is a rare JC virus (JCV)-related disease in immunocompromised patients, characterized by lytic infection of the cerebellar granule cell layer. To enable early diagnosis and intervention, we identify features of GCN and describe possible aspects of disease heterogeneity. We report on two new cases of GCN in HIV-infected patients of whom we retrospectively assessed clinical and radiologic data. In addition, we carried out a literature search and review of clinical, radiologic and histopathologic findings of all published GCN cases. Including the two new cases reported here, a total of 18 GCN cases were included in this study. HIV infection, present in 12 of the cases, was the most common underlying condition, followed by monoclonal antibody treatment which was present in three cases. Cerebellar atrophy was detected in all except two cases. In 12 patients a heterogeneous distribution pattern of white matter changes in the cerebellum and brainstem was observed. Imaging findings in GCN are remarkably heterogeneous; exhibiting cerebellar atrophy, as well as white matter pathology, particularly in the adjacent infratentorial white matter. This suggests an overlap of GCN with other JCV-related diseases, such as progressive multifocal leukoencephalopathy.