The encephalitis mediated by antibodies against Leucine-rich, glioma inactivated 1 protein (anti-LGI1 encephalitis) predominantly affects men (M:F, 6:4) and mostly older than 60 years. The disease has two distinct clinical phases: The acute phase in which the majority of patients develop severe short-term memory deficits (unable to remember events or experiences that occurred a few minutes earlier). This memory impairment can be preceded or accompanied by one or more of the following: hyponatremia (60% of patients), a highly distinctive type of seizures called facio-brachial dystonic seizures (\~40% of patients), along with confusion, irritability and other types of focal seizures or less frequently, generalized seizures. In addition, many patients at this stage have symptoms of REM sleep behavior disorder. In this stage, the CSF may show pleocytosis or mild increase of proteins, the EEG is usually abnormal, and in \~60% of the patients the MRI shows typical increased FLAIR signal in medial temporal lobes (11). There is a clinical sub-phenotype (\~13% of patients) in which the disease presents as a rapidly progressive cognitive decline without the indicated FLAIR MRI changes. About 70% of patients improve rapidly with corticosteroids and immunotherapy (eg, intravenous immunoglobulins and/or plasma exchange), but the improvement is often partial. After the acute phase, there is a chronic or residual phase which represents the interval from improvement of initial symptoms until the disease is considered no longer active and the remaining symptoms are thought to be irreversible. This chronic phase may take several months (it has been less well studied), and is characterized by the absence of CSF pleocytosis and inflammatory MRI changes (albeit this may show residual hippocampal atrophy), and very low or undetectable titers of serum antibodies. Most patients are unable to return to their job or previous activities due to residual (irreversible) memory or cognitive deficits accompanied by signs of moderate brain atrophy. In addition, we and others have shown that about 27-35% of patients have relapsing symptoms after improving from the acute phase (. Although acute symptomatic seizures (facio-brachial dystonic and others) occur in \~90% of patients during the acute phase of the disease, less than 10% of patients develop chronic epilepsy often associated with hippocampal sclerosis. Therefore, the prevailing concept on this disease suggests a syndrome and clinical course in which the acute phase shows rapid, albeit partial, response to immunotherapy, and the symptoms of the chronic phase represent a burnout or irreversible process, in which the disease is no longer active, and the potential improvement of remaining symptoms is uncertain.
Here investigators postulate that a better knowledge of this stage will improve treatment decisions and outcome.
In Aim 1, the post-acute stage will be clinically characterized.
In Aim 2, the impact of cognitive rehabilitation will be assessed.
In Aim 3, a mouse model of anti-LGI1 encephalitis will be used to determine the underlying mechanisms and treatment of the postacute stage.
Patients with Antibody-mediated LGI-1 encephalitis in the post-acute stage of the disease;
Patients has been discharged from hospital (acute phase).
Inability to obtain informed consent;
Inability to travel to the center.
Single group
Remote cognitive rehabilitation program
BehavioralBehavioral: Remote cognitive rehabilitation program Remote cognitive rehabilitation program will be performed through an online validated platform (Guttmann NeuroPersonalTrainer: https://gnpt.es/) run by the psychologists team. This is a Sanitary Product with CE certification (Sanitary Product RPS/430/2014; International Patent \[PCT/ES2008/00677\]) and here will be used within its approved indications. The rehabilitation program will increase in difficulty and decrease in frequency during the first year of follow-up (V1-V3).
Age
Age measured in years
Gender
Male or female
Handedness
Right- or Left-handed
General medical history
Description of the most important issues compiled in the general medical history of the participant
LGI-1 antibodies
Determined with brain tissue immunohistochemistry and cell - based assays
HLA genotyping
performed by standard techniques based on DNA - PCR and polymorphism identification by reverse hybridization with specific probes and fluorescence labelling of hybridized fragments (PCR - SSOP) (Immucor GTI Diagnostics Inc.Waukesha USA) in combination with genomic DNA sequencing by Sanger methodology (PCRSBT).
Immune/inflammatory signaling-target gene expression pathways
RNA/NanoString analysis of targeted gene expression related to activation/function of B cells, T cells, microglia, and other interleukin/ chemokine signaling. Whole blood/CSF will be collected using PAXgene® Blood RNA tubes (Qiagen) shipped to the centers. Total RNA will be extracted using PAXgene® Blood RNA Kit (Qiagen). RNA samples are quantified using Qubit 2.0 Fluorometer (Life Technologies) and RNA integrity is determined with Agilent 2100 Bioanalyzer (Agilent Technologies). Expression levels of 44 genes related to immunological pathways and cytokines (Annex,Table) will be measured with the nCounter® Digital Analyzer (NanoString), as reported (Armangue et al., Mol Genet Metab 2017;122:134-9). Twenty healthy participants will serve as controls (single evaluation).
NfL levels
determined in serum and CSF using the SiMoA Quanterix technique, as reported (Guasp et al., Neurology 2022;98:e1489 - 98). Age-and sex-matched healthy participants from previous studies will serve as controls.
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