An Assay to Determine Mechanisms of Rapid Autoantibody-Induced Neurotransmitter Receptor Endocytosis and Vesicular Trafficking in Autoimmune Encephalitis

Cerebrospinal fluid proteomics indicates immune dysregulation and neuronal dysfunction in antibody associated autoimmune encephalitis

Autoimmune Encephalitis (AE) spans a group of non-infectious inflammatory conditions of the central nervous system due to an imbalanced immune response. Aiming to elucidate the pathophysiological mechanisms of AE, we applied an unsupervised proteomic approach to analyze the cerebrospinal fluid (CSF) protein profile of AE patients with autoantibodies against N-methyl-d-aspartate receptor (NMDAR) (n = 9), leucine-rich glioma-inactivated protein 1 (LGI1) (n = 9), or glutamate decarboxylase 65 (GAD65) (n = 8) compared to 9 patients with relapsing-remitting multiple sclerosis as inflammatory controls, and 10 patients with somatic symptom disorder as non-inflammatory controls. We found a dysregulation of the complement system, a disbalance between pro-inflammatory and anti-inflammatory proteins on the one hand, and dysregulation of proteins involved in synaptic transmission, synaptogenesis, brain connectivity, and neurodegeneration on the other hand to a different extent in all AE subtypes compared to non-inflammatory controls. Furthermore, elevated levels of several proteases and reduction in protease inhibitors could be detected in all AE subtypes compared to non-inflammatory controls. Moreover, the different AE subtypes showed distinct protein profiles compared to each other and inflammatory controls which may facilitate future identification of disease-specific biomarkers. Overall, CSF proteomics provides insights into the complex pathophysiological mechanisms of AE, including immune dysregulation, neuronal dysfunction, neurodegeneration, and altered protease function.

Anti-N-methyl-D-aspartate receptor encephalitis: A review of pathogenic mechanisms, treatment, prognosis

Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is a treatable autoimmune disorder characterized by prominent neuropsychiatric symptoms that predominantly affects children and young adults. In this review, we discuss the pathogenic mechanisms and immunologic triggers of anti-NMDAR encephalitis, and provide an overview of treatment and prognosis of this disorder, with specific focus on the management of common symptoms, complications, and patients during pregnancy. Most patients respond well to first-line treatment and surgical resection of tumors. When first-line immunotherapy fails, second-line immunotherapy can often improve outcomes. In addition, treatment with immunomodulators and tumor resection are effective treatment strategies for pregnant patients. Benzodiazepines are the preferred treatment for patients with catatonia, and electroconvulsive therapy (ECT) may be considered when pharmacological treatment is ineffective. Age, antibody titer, cerebellar atrophy, levels of biomarkers such as C-X-C motif chemokine 13 (CXCL13), cell-free mitochondrial (mt)DNA in cerebral serum fluid (CSF), and timing from symptom onset to treatment are the main prognostic factors. Patients without tumors or those who receive insufficient immunotherapy during the first episode are more likely to relapse.