Yang, Binxia

ABSTRACT Objectives To investigate the value of cytokine, chemokine, and neurofilament light chain (NfL) concentrations in predicting relapse risk, chronic epilepsy, and functional impairment in LGI1 autoimmune encephalitis (AE). Methods Cytokines/chemokines (IL‐1‐beta, IL‐2, IL‐4, IL‐5, IL‐6, IL‐8/CXCL8, IL‐10, IL‐12p70, IL‐13, IL‐17A, GM‐CSF, TNF‐alpha, IFN‐gamma, CXCL9, CXCL10, CXCL13, BAFF) and NfL concentrations were measured in CSF and paired serum from LGI1‐AE patients evaluated at Mayo Clinic (01/2015–02/2024), using a multiplex immunoassay system (ELLA, Bio‐Techne) and correlated with clinical outcomes. A laboratory‐based cohort of LGI1‐IgG‐positive patients and control cohorts, including patients with mixed non‐inflammatory disorders (MNID), Alzheimer's disease (AD), and temporal lobe epilepsy (TLE) were analyzed. Results Forty‐four patients with LGI1‐AE were included; 29 (66%) were male, with a median age of 68.5 years (range, 8–85). Median time from symptom onset to CSF sampling was eight months (IQR, 3–17); 19/42 (45%) experienced a clinical relapse and 27% developed chronic epilepsy. Serum IL‐6, serum and CSF IL‐8/CXCL8, and IL‐17A were higher in LGI1‐IgG positive patients than MNID ( p < 0.05). TLE cytokine/chemokine profiles were similar to LGI1 AE; AD patients had lower serum IL‐6 and CSF IL‐8/CXCL8 ( p = 0.04; p = 0.01), and higher serum IL‐17A and GM‐CSF ( p = 0.004; p = 0.01) than LGI1‐AE. Higher CSF IL‐6 and IL‐8/CXCL8 in LGI1‐AE associated with clinical relapse ( p < 0.05) and higher CSF NfL associated with chronic epilepsy ( p = 0.01). Conclusion Elevations in IL‐6, IL‐8/CXCL8, and IL‐17A were identified in this LGI1‐AE cohort. CSF IL‐6, IL‐8/CXCL8, and NfL levels are potential prognostic biomarkers for risk of relapse and chronic epilepsy in LGI1‐AE.

AbstractDefining the CSF cytokine/chemokine and injury biomarker signature of glial fibrillary acidic protein (GFAP) autoimmunity can inform immunopathogenesis. CSF GFAP‐IgG‐positive samples (N = 98) were tested for 17 cytokines/chemokines, neurofilament light chain (NfL), and GFAP (ELLA, Bio‐Techne). Controls included non‐inflammatory (N = 42), AQP4‐IgG‐positive (N = 83), CNS infections (N = 13), and neurosarcoidosis (N = 32). IL5, IL6, IL10, IL8/CXCL8, CXCL9, CXCL10, CXCL13, BAFF, GM‐CSF, IFN‐gamma, and TNF‐alpha concentrations were higher compared to non‐inflammatory controls (P < 0.01). GFAP concentrations were similar to those of AQP4‐IgG‐positive patients; NfL was higher (P < 0.001) and correlated with MRI changes and outcomes. CSF cytokine/chemokine findings in GFAP autoimmunity correlate with histopathology; GFAP and NfL hold promise as disease biomarkers.

ObjectiveTo evaluate the cerebrospinal fluid (CSF) cytokine/chemokine profile of central nervous system (CNS) neurosarcoidosis (NS), and its utility in differential diagnosis, treatment, and prognostication.MethodsIn this case–control study, we validated 17 cytokines/chemokines (interleukin [IL]‐1‐beta, IL‐2, IL‐4, IL‐5, IL‐6, IL‐10, IL‐12p70, IL‐13, IL‐17A, BAFF, IL‐8/CXCL8, CXCL9, CXCL10, CXCL13, GM‐CSF, interferon‐gamma, and tumor necrosis factor [TNF]‐alpha) in a multiplexed automated immunoassay system (ELLA; Bio‐Techne, Minneapolis, MN, USA), and assessed them in CSF and serum of symptomatic patients with probable or definite CNS NS (01/2011–02/2023) with gadolinium enhancement and/or CSF pleocytosis. Patients with multiple sclerosis, primary CNS lymphoma, aquaporin‐4 immunoglobulin G positivity, non‐inflammatory disorders, and healthy individuals were used as controls.ResultsA total of 32 NS patients (59% women; median age, 59 years [19–81]) were included; concurrent sera were available in 12. CSF controls consisted of 26 multiple sclerosis, 8 primary CNS lymphoma, 84 aquaporin‐4 immunoglobulin G positive, and 34 patients with non‐inflammatory disorders. Gadolinium enhancement was present in 31 of 32 NS patients, and CSF pleocytosis in 27 of 32 (84%). CSF IL‐2, IL‐6, IL‐10, IL‐13, BAFF, IL‐8/CXCL8, CXCL9, CXCL10, CXCL13, GM‐CSF, interferon‐gamma, and TNF‐alpha levels were significantly higher in NS patients compared with non‐inflammatory controls (p ≤ 0.02); elevations were more common in CSF than serum. Concurrent elevation of IL‐6, CXCL9, CXCL10, GM‐CSF, interferon‐gamma, and TNF‐alpha was present in 18 of 32 NS patients, but only in 1 control. Elevated IL‐6, IL‐10, IL‐13, CXCL9, CXL10, GM‐CSF, and TNF‐alpha associated with measures of disease activity.InterpretationNS CSF cytokine/chemokine profiles suggest T cell (mainly T helper cell type 1), macrophage, and B‐cell involvement. These signatures aid in NS diagnosis, indicate disease activity, and suggest therapeutic avenues. ANN NEUROL 2024;96:704–714

ObjectivesTo report an autoimmune paraneoplastic encephalitis characterized by immunoglobulin G (IgG) antibody targeting synaptic protein calmodulin kinase‐like vesicle‐associated (CAMKV).MethodsSerum and cerebrospinal fluid (CSF) samples harboring unclassified antibodies on murine brain‐based indirect immunofluorescence assay (IFA) were screened by human protein microarray. In 5 patients with identical cerebral IFA staining, CAMKV was identified as top‐ranking candidate antigen. Western blots, confocal microscopy, immune‐absorption, and mass spectrometry were performed to substantiate CAMKV specificity. Recombinant CAMKV‐specific assays (cell‐based [fixed and live] and Western blot) provided additional confirmation.ResultsOf 5 CAMKV‐IgG positive patients, 3 were women (median symptom‐onset age was 59 years; range, 53–74). Encephalitis‐onset was subacute (4) or acute (1) and manifested with: altered mental status (all), seizures (4), hyperkinetic movements (4), psychiatric features (3), memory loss (2), and insomnia (2). Paraclinical testing revealed CSF lymphocytic pleocytosis (all 4 tested), electrographic seizures (3 of 4 tested), and striking MRI abnormalities in all (mesial temporal lobe T2 hyperintensities [all patients], caudate head T2 hyperintensities [3], and cortical diffusion weighted hyperintensities [2]). None had post‐gadolinium enhancement. Cancers were uterine adenocarcinoma (3 patients: poorly differentiated or neuroendocrine‐differentiated in 2, both demonstrated CAMKV immunoreactivity), bladder urothelial carcinoma (1), and non‐Hodgkin lymphoma (1). Two patients developed encephalitis following immune checkpoint inhibitor cancer therapy (atezolizumab [1], pembrolizumab [1]). All treated patients (4) demonstrated an initial response to immunotherapy (corticosteroids [4], IVIG [2]), though 3 died from cancer.InterpretationCAMKV‐IgG is a biomarker of immunotherapy‐responsive paraneoplastic encephalitis with temporal and extratemporal features and uterine cancer as a prominent oncologic association. ANN NEUROL 2024;96:21–33

Autoimmune movement disorders are increasingly recognized, but isolated tremor is extremely rare. We describe a 70‐year‐old male with rapidly progressive, severe postural and intention tremor and weight loss. His cerebrospinal fluid was inflammatory and harbored a neural tissue‐restricted antibody. The autoantigen was identified by immunoprecipitation and mass spectrometry and confirmed by antigen‐specific assays to be specific for tenascin‐R. He was investigated for cancer and diagnosed with follicular lymphoma that expressed tenascin‐R suggesting a paraneoplastic origin; cancer treatment and immunotherapy led to complete recovery. With this individualized patient approach and antibody discovery, we expand the spectrum of antibodies accompanying autoimmune hyperkinetic movement disorders. ANN NEUROL 2023;94:502–507

The antigen specificity of Anti‐Neuronal Nuclear Antibody‐type 3 (ANNA3)‐IgG is unknown. We identified Dachshund‐homolog 1 (DACH1) as the ANNA3 autoantigen and confirmed it by antigen‐specific assays, immunohistochemical colocalization and immune absorption experiments. Patients' median age was 63.5 years (range, 49–88); 67% were female. Neurological manifestations (information available for 30 patients) included one or more of neuropathy, 12; cognitive difficulties, 11; ataxia, 8; dysautonomia, 7. Evidence of a neoplasm was present in 27 of 30 (90%), most of neuroendocrine lineage. DACH1‐IgG is rare and represents a novel proposed biomarker of neurological autoimmunity and cancer. ANN NEUROL 2022;91:670–675