Breast Cancer Specificities of Patients With Anti-Ri Paraneoplastic Neurologic Syndromes.

Background And Objectives: Breast cancers (BCs) of patients with paraneoplastic neurologic syndromes and anti-Yo antibodies (Yo-PNS) overexpress human epidermal growth factor receptor 2 (HER2) and display genetic alterations and overexpression of the Yo-onconeural antigens. They are infiltrated by an unusual proportion of B cells. We investigated whether these features were also observed in patients with PNS and anti-Ri antibodies (Ri-PNS).

Long-Term Clinical and Biological Prognostic Factors of Anti-NMDA Receptor Encephalitis in Children.

Background And Objectives: Anti-NMDAR encephalitis (NMDARE) is a severe neurologic condition, and recently, the NMDAR Encephalitis One-Year Functional Status (NEOS) score has emerged as a 1-year prognostic tool. This study aimed to evaluate NEOS score and biomarker (neurofilament light chains [NfL], total-Tau protein, glial fibrillary acidic protein, and serum cytokines) correlation with modified Rankin Scale (mRS), cognitive impairment, and clinical recovery in pediatric NMDARE over 2 years.

Methods: In this French multicenter observational study, 104 pediatric patients with NMDARE were followed for a minimum of 2 years.

Novel risk loci in LGI1-antibody encephalitis: genome-wide association study discovery and validation cohorts.

Encephalitis with antibodies to leucine-rich glioma-inactivated 1 (LGI1-Ab-E) is a common form of autoimmune encephalitis, presenting with seizures and neuropsychiatric changes, predominantly in older males. More than 90% of patients carry the human leucocyte antigen (HLA) class II allele, HLA-DRB1*07:01. However, this is also present in 25% of healthy controls.

Anti-RGS8 paraneoplastic cerebellar ataxia is preferentially associated with a particular subtype of Hodgkin's lymphoma.

Ataxia with anti-regulator of G-protein signaling 8 autoantibodies (RGS8-Abs) is an autoimmune disease recently described in four patients. The present study aimed to identify other patients with RGS8-Abs, describe their clinical features, including the link between RGS8-related autoimmune cerebellar ataxia (ACA) and cancer. Patients with RGS8-Abs were identified retrospectively in the biological collections of the French Reference Center for Paraneoplastic Neurological Syndrome and the University of California San Francisco Center for Encephalitis and Meningitis.

Specific clinical and radiological characteristics of anti-NMDA receptor autoimmune encephalitis following herpes encephalitis.

Background: Herpes simplex virus encephalitis (HSE) frequently triggers secondary anti-N-methyl-D-aspartate receptor encephalitis (NMDARE), but markers predicting the occurrence of this entity (HSE-NMDARE) are lacking.

Methods: We conducted a retrospective description of patients with HSE-NMDARE diagnosed between July 2014 and August 2022 and compared them to both patients with regular forms of HSE and NMDARE.

Results: Among the 375 patients with NMDARE, 13 HSE-NMDARE were included.

HLA and KIR genetic association and NK cells in anti-NMDAR encephalitis.

Introduction: Genetic predisposition to autoimmune encephalitis with antibodies against N-methyl-D-aspartate receptor (NMDAR) is poorly understood. Given the diversity of associated environmental factors (tumors, infections), we hypothesized that human leukocyte antigen () and killer-cell immunoglobulin-like receptors (), two extremely polymorphic gene complexes key to the immune system, might be relevant for the genetic predisposition to anti-NMDAR encephalitis. Notably, KIR are chiefly expressed by Natural Killer (NK) cells, recognize distinct HLA class I allotypes and play a major role in anti-tumor and anti-infection responses.

Ketamine alleviates NMDA receptor hypofunction through synaptic trapping.

Activity-dependent modulations of N-methyl-D-aspartate glutamate receptor (NMDAR) trapping at synapses regulate excitatory neurotransmission and shape cognitive functions. Although NMDAR synaptic destabilization has been associated with severe neurological and psychiatric conditions, tuning NMDAR synaptic trapping to assess its clinical relevance for the treatment of brain conditions remains a challenge. Here, we report that ketamine (KET) and other clinically relevant NMDAR open channel blockers (OCBs) promote interactions between NMDAR and PDZ-domain-containing scaffolding proteins and enhance NMDAR trapping at synapses.

HLA-DR3 ~ DQ2 associates with sensory neuropathy in paraneoplastic neurological syndromes with Hu antibodies.

Objectives: To investigate the association between human leukocyte antigen (HLA) and paraneoplastic neurological syndromes (PNS) with Hu antibodies, and potential specificities according to clinical presentation and cancer status.

Methods: HLA genotypes at four-digit resolution were imputed from available genome-wide association data. Allele carrier frequencies were compared between patients (whole cohort, n = 100, and according to clinical presentation and cancer status) and matched healthy controls (n = 508) using logistic regression controlled by the three main principal components.

Mechanism, and treatment of anti-CV2/CRMP5 autoimmune pain.

Paraneoplastic neurological syndromes arise from autoimmune reactions against nervous system antigens due to a maladaptive immune response to a peripheral cancer. Patients with small cell lung carcinoma or malignant thymoma can develop an autoimmune response against the CV2/collapsin response mediator protein 5 (CRMP5) antigen. For reasons that are not understood, approximately 80% of patients experience painful neuropathies.

Comparative Study of Paraneoplastic and Nonparaneoplastic Autoimmune Encephalitis With GABAR Antibodies.

Background And Objectives: While patients with paraneoplastic autoimmune encephalitis (AE) with gamma-aminobutyric-acid B receptor antibodies (GABAR-AE) have poor functional outcomes and high mortality, the prognosis of nonparaneoplastic cases has not been well studied.

Methods: Patients with GABAR-AE from the French and the Dutch Paraneoplastic Neurologic Syndromes Reference Centers databases were retrospectively included and their data collected; the neurologic outcomes of paraneoplastic and nonparaneoplastic cases were compared. Immunoglobulin G (IgG) isotyping and human leukocyte antigen (HLA) genotyping were performed in patients with available samples.

Predictors and Clinical Characteristics of Relapses in LGI1-Antibody Encephalitis.

Background And Objectives: Relapses occur in 15%-25% of patients with leucine-rich glioma-inactivated 1 antibody (LGI1-Ab) autoimmune encephalitis and may cause additional disability. In this study, we clinically characterized the relapses and identified factors predicting their occurrence.

Methods: This is a retrospective chart review of patients with LGI1-Ab encephalitis diagnosed at our center between 2005 and 2022.

Dysautonomia in anti-Hu paraneoplastic neurological syndromes.

Background And Objectives: Dysautonomia has been associated with paraneoplastic neurological syndrome (PNS)-related mortality in anti-Hu PNS, but its frequency and spectrum remain ill-defined. We describe anti-Hu patients with dysautonomia, estimate its frequency, and compare them to patients without dysautonomia.

Methods: Patients with anti-Hu antibodies diagnosed in the study centre (1990-2022) were retrospectively reviewed; those with autonomic signs and symptoms were identified.

Neurological autoimmunity in melanoma patients: a comparison between those exposed and non-exposed to immune checkpoint inhibitors.

Background: The clinical spectrum of melanoma-associated neurological autoimmunity, whether melanoma-associated paraneoplastic neurological syndromes (PNS) or induced by immune checkpoint inhibitors (ICI), is not well characterized. We aim to describe the clinical spectrum of melanoma-associated neurological autoimmunity.

Methods: A systematic review of the literature combined with patients from French databases of paraneoplastic neurological syndromes was conducted.

Revisiting anti-Hu paraneoplastic autoimmunity: phenotypic characterization and cancer diagnosis.

Anti-Hu are the most frequent antibodies in paraneoplastic neurological syndromes, mainly associated with an often limited stage small cell lung cancer. The clinical presentation is pleomorphic, frequently multifocal. Although the predominant phenotypes are well characterized, how different neurological syndromes associate is unclear.

Different Genetic Signatures of Small-Cell Lung Cancer Characterize Anti-GABA R and Anti-Hu Paraneoplastic Neurological Syndromes.

Objective: Small-cell lung cancer (SCLC) is the malignancy most frequently associated with paraneoplastic neurological syndromes (PNS) and can trigger different antibody responses against intracellular (Hu) or neuronal surface (GABA R) antigens. Our aim was to clarify whether the genomic and transcriptomic features of SCLC are different in patients with anti-GABA R or anti-Hu PNS compared with SCLC without PNS.

Methods: A total of 76 SCLC tumor samples were collected: 34 anti-Hu, 14 anti-GABA R, and 28 SCLC without PNS.

Trigeminal Nerve Involvement in Bulbar-Onset Anti-IgLON5 Disease.

Objectives: Anti-IgLON5 disease (IgLON5-D) may present with a bulbar-onset motor neuron disease-like phenotype, mimicking bulbar-onset amyotrophic lateral sclerosis. Recognition of their distinctive clinical and paraclinical features may help for differential diagnosis. We report 2 cases of atypical trigeminal neuropathy in bulbar-onset IgLON5-D.

Peripheral nervous system involvement accompanies central nervous system involvement in anti-glial fibrillary acidic protein (GFAP) antibody-related disease.

Background: Glial fibrillary acidic protein (GFAP) is expressed by astrocytes in the central nervous system (CNS), but also by immature and regenerative Schwann cells in the peripheral nervous system (PNS). GFAP antibodies (GFAP-Abs) in cerebrospinal fluid (CSF) have been mainly described in patients with meningoencephalomyelitis. We aimed to study PNS symptoms in patients with CSF GFAP-Abs.

Spatial and Ecological Factors Modulate the Incidence of Anti-NMDAR Encephalitis-A Systematic Review.

Anti-NMDAR encephalitis has been associated with multiple antigenic triggers (i.e., ovarian teratomas, prodromal viral infections) but whether geographic, climatic, and environmental factors might influence disease risk has not been explored yet.

Anti-LGI1 Encephalitis With Co-occurring IgLON5 Antibodies: Clinical Features and Human Leukocyte Antigen Haplotypes.

Objectives: Autoimmune encephalitis (AE) with antibodies against LGI1 and IgLON5 are clinically distinctive but share some particularities such as a strong association with specific human leukocyte antigen (HLA) class II alleles.

Methods: We clinically describe a patient with double positivity for LGI1 and IgLON5 antibodies. In addition, we conducted specific immunodepletion with the patient's serum and HLA typing and investigated the presence of serum IgLON5 antibodies in a cohort of 23 anti-LGI1 patients carrying the HLA predisposing for anti-IgLON5 encephalitis.

Prognostic Value of Persistent CSF Antibodies at 12 Months in Anti-NMDAR Encephalitis.

Background And Objectives: Anti-NMDA receptor (NMDAR) encephalitis is defined by the presence of antibodies (Abs) targeting the NMDAR in the CSF. This study aimed to determine the prognostic value of persistent CSF NMDAR-Abs during follow-up.

Methods: This retrospective observational study included patients diagnosed with anti-NMDAR encephalitis in the French Reference Center for Paraneoplastic Neurological Syndromes and Autoimmune Encephalitis and for whom CSF samples were obtained at diagnosis and >4 months of follow-up to evaluate CSF NMDAR-Ab persistence.

Anti-AGO1 Antibodies Identify a Subset of Autoimmune Sensory Neuronopathy.

Background And Objectives: Autoantibodies (Abs) improve diagnosis and treatment decisions of idiopathic neurologic disorders. Recently, we identified Abs against Argonaute (AGO) proteins as potential autoimmunity biomarkers in neurologic disorders. In this study, we aim to reveal (1) the frequency of AGO1 Abs in sensory neuronopathy (SNN), (2) titers and IgG subclasses, and (3) their clinical pattern including response to treatment.