Vezzani, Annamaria

Immune-mediated epilepsies represent an etiologically unique category defined by immune activation within the central nervous system that initiates a pathophysiological cascade resulting in seizures, encephalopathy, and sometimes epileptogenesis with long-term epilepsy. Once considered rare and largely confined to paraneoplastic or postinfectious syndromes, immune-mediated and inflammatory mechanisms are now recognized across a broad spectrum ranging from acute autoimmune encephalitis with reversible seizures, new-onset refractory status epilepticus, or febrile illness-related refractory status epilepticus, to chronic autoimmune-associated epilepsy and drug-refractory structural epilepsies. This review integrates historical perspectives, mechanistic insights from animal and human studies, and contemporary clinical frameworks. It synthesizes advances in neuroimmunology, clinical phenotyping, diagnostics, immunomodulatory and antiseizure therapies, neuromodulation, and patient and family centered outcomes, and outlines future directions focused on biomarker-driven precision medicine, disease-modifying strategies, and interdisciplinary care models.

AbstractNew onset refractory status epilepticus (NORSE), including its subtype with a preceding febrile illness known as febrile infection‐related epilepsy syndrome (FIRES), is one of the most severe forms of status epilepticus. The exact causes of NORSE are currently unknown, and there is so far no disease‐specific therapy. Identifying the underlying pathophysiology and discovering specific biomarkers, whether immunologic, infectious, genetic, or other, may help physicians in the management of patients with NORSE. A broad spectrum of biomarkers has been proposed for status epilepticus patients, some of which were evaluated for patients with NORSE. Nonetheless, none has been validated, due to significant variabilities in study cohorts, collected biospecimens, applied analytical methods, and defined outcome endpoints, and to small sample sizes. The NORSE Institute established an open NORSE/FIRES biorepository for health‐related data and biological samples allowing the collection of biospecimens worldwide, promoting multicenter research and sharing of data and specimens. Here, we suggest standard operating procedures for biospecimen collection and biobanking in this rare condition. We also propose criteria for the appropriate use of previously collected biospecimens. We predict that the widespread use of standardized procedures will reduce heterogeneity, facilitate the future identification of validated biomarkers for NORSE, and provide a better understanding of the pathophysiology and best clinical management for these patients.

Abstract Aims The causes of distinct patterns of reduced cortical thickness in the common human epilepsies, detectable on neuroimaging and with important clinical consequences, are unknown. We investigated the underlying mechanisms of cortical thinning using a systems‐level analysis. Methods Imaging‐based cortical structural maps from a large‐scale epilepsy neuroimaging study were overlaid with highly spatially resolved human brain gene expression data from the Allen Human Brain Atlas. Cell‐type deconvolution, differential expression analysis and cell‐type enrichment analyses were used to identify differences in cell‐type distribution. These differences were followed up in post‐mortem brain tissue from humans with epilepsy using Iba1 immunolabelling. Furthermore, to investigate a causal effect in cortical thinning, cell‐type‐specific depletion was used in a murine model of acquired epilepsy. Results We identified elevated fractions of microglia and endothelial cells in regions of reduced cortical thickness. Differentially expressed genes showed enrichment for microglial markers and, in particular, activated microglial states. Analysis of post‐mortem brain tissue from humans with epilepsy confirmed excess activated microglia. In the murine model, transient depletion of activated microglia during the early phase of the disease development prevented cortical thinning and neuronal cell loss in the temporal cortex. Although the development of chronic seizures was unaffected, the epileptic mice with early depletion of activated microglia did not develop deficits in a non‐spatial memory test seen in epileptic mice not depleted of microglia. Conclusions These convergent data strongly implicate activated microglia in cortical thinning, representing a new dimension for concern and disease modification in the epilepsies, potentially distinct from seizure control.

AbstractFebrile infection‐related epilepsy syndrome (FIRES) is a rare catastrophic epileptic encephalopathy that presents suddenly in otherwise normal children and young adults causing significant neurological disability, chronic epilepsy, and high rates of mortality. To suggest a therapy protocol to improve outcome of FIRES, workshops were held in conjunction with American Epilepsy Society annual meeting between 2017 and 2019. An international group of pediatric epileptologists, pediatric neurointensivists, rheumatologists and basic scientists with interest and expertise in FIRES convened to propose an algorithm for a standardized approach to the diagnosis and treatment of FIRES. The broad differential for refractory status epilepticus (RSE) should include FIRES, to allow empiric therapies to be started early in the clinical course. FIRES should be considered in all previously healthy patients older than two years of age who present with explosive onset of seizures rapidly progressing to RSE, following a febrile illness in the preceding two weeks. Once FIRES is suspected, early administrations of ketogenic diet and anakinra (the IL‐1 receptor antagonist that blocks biologic activity of IL‐1β) are recommended.

Febrile infection‐related epilepsy syndrome (FIRES) is a devastating epileptic encephalopathy with limited treatment options and an unclear etiology. Anakinra is a recombinant version of the human interleukin‐1 receptor antagonist used to treat autoinflammatory disorders. This is the first report of anakinra for treatment of a child with super‐refractory status epilepticus secondary to FIRES. Anakinra was well tolerated and effective. Cerebral spinal fluid analysis revealed elevated levels of proinflammatory cytokines before treatment that normalized on anakinra, suggesting a potential pathogenic role for neuroinflammation in FIRES. Further studies are required to assess anakinra efficacy and dosing, and to further delineate disease etiology. Ann Neurol 2016;80:939–945