Citations

AbstractObjectiveWe describe neurologic phenotype, clinical associations, and outcomes in autoimmune brainstem encephalitis.MethodsMedical records of neural‐IgG positive autoimmune brainstem encephalitis patients diagnosed at Mayo Clinic (January 1, 2006–December 31, 2022) were reviewed.ResultsNinety‐eight patients (57 male) were included. Median age of symptom onset was 51 years (range, 8 months‐85 years). Frequent presenting features were ≥1: diplopia (80%), ataxia (78%), dysarthria (68%), vestibulocochlear symptoms (67%), dysphagia (61%), nausea/vomiting (42%), and facial weakness (32%). Altered mental status (11%) was uncommon. Neural antibodies detected were as follows: KLHL‐11 (26 patients), GAD65 (high titer, 12), ANNA‐1 (anti‐Hu, 8), ANNA‐2 (anti‐Ri, 8), Ma2 (7), IgLON‐5 (6), AQP4 (6), MOG (4), glycine receptor (4), GQ1B (4), PCA‐1 (anti‐Yo, 4), DPPX (2), neurochondrin (2), neurofilament (2), NMDA‐R (2), AGNA‐1 (SOX‐1, 1), ANNA‐3 (DACH1, 1), amphiphysin (1), CRMP‐5 (1), ITPR‐1 (1), PCA‐Tr (DNER, 1), and PDE10A (1). Cancer was identified in 55 patients: germ cell (23 patients; 3 extra‐testicular), ductal breast adenocarcinoma (8), small cell carcinoma (6, lung 4), adenocarcinomas (6), neuroendocrine carcinoma (3), hematologic (2), squamous cell (2), and other (7). Median modified Ranking score (mRS) at last follow‐up was 3 (range, 0–6). Factors associated with poor outcome included abnormal brain MRI, bulbar symptoms, and elevated CSF IgG index. Kaplan–Meier analysis revealed faster progression to wheelchair in patients who were immunotherapy refractory and with elevated CSF IgG index. Diagnostic criteria for autoimmune brainstem encephalitis (definite and probable) are proposed.InterpretationAutoimmune brainstem encephalitis is a distinct clinical subphenotype of autoimmune encephalitis. Abnormal brain MRI, bulbar symptoms, and elevated CSF‐IgG index associate with poor outcome.

AbstractObjectiveTo describe the phenotypes, oncological associations, biomarker profiles, and outcomes across different age groups in patients with ANNA1 (anti‐Hu) autoimmunity.MethodsA retrospective review of patients with ANNA1‐IgG in serum/CSF between January 1, 2001, and December 31,2019 was performed. Patients were classified into three groups based on the age of symptom onset. Phage immunoprecipitation sequencing (PhIP‐Seq) and neurofilament light chain (NfL) measurements were done in patient sera/CSF with archived samples.ResultsOf 122 patients, 81 (66%), 20 (16%), and 21 (17%) patients belonged to older adults, young adults, and pediatric groups, respectively. Lung cancer and neuromuscular presentations were more common in older adults (p < 0.001), while limbic encephalitis and neuroblastoma were more common in pediatric patients (p < 0.005). Most young adults (75%) did not have cancer identified. Proportions of patients with a favorable response to immunotherapy were 20%, 30%, and 52% among older adults, young adults, and pediatric groups, respectively. PhIP‐Seq demonstrated significant enrichment for ELAVL4 peptides especially for amino acids 240–289, in the majority of samples evaluated (36/67, 54%). ZIC and SOX2 peptides were significantly enriched in those with central nervous system presentations. Serum NfL levels were elevated in patients with cancer and those with poor long‐term outcomes.InterpretationYoung adults with ANNA1 autoimmunity phenotypically resembled older adults but rarely had an underlying cancer. Pediatric patients frequently presented with limbic encephalitis and neuroblastoma and often responded favorably to immunotherapy. Distinct antigenic signatures may underlie differences in clinical presentations. Serum NfL levels may be a biomarker of poor long‐term outcomes in ANNA1 autoimmunity.

AbstractObjectiveThis study aimed to evaluate the diagnostic accuracy of dried blood spot (DBS) compared with conventional serum Aquaporin‐4‐IgG (AQP4‐IgG) testing.MethodsProspective multicenter diagnostic study was conducted between April 2018 and October 2023 across medical centers in the United States, Uganda, and the Republic of Guinea. Neuromyelitis optica spectrum disorder (NMOSD) patients and controls collected blood on filter paper cards along with concurrent serum samples. These samples underwent analysis using flow cytometric live‐cell‐based assays (CBA) and enzyme‐linked immunosorbent assay (ELISA) to determine AQP4 serostatus. The accuracy of AQP4‐IgG detection between DBS and serum (gold standard) was compared.ResultsAmong 150 participants (47 cases, 103 controls), there was a strong correlation between DBS and serum samples (Spearman's correlation coefficient of 0.82). The AUC was 0.97 (95% CI: 0.92–0.99). AQP4‐IgG detection through DBS showed 87.0% sensitivity (95% CI: 0.74–0.95) and 100% specificity (95% CI: 0.96–1.00) using CBA, and 65.2% sensitivity (95% CI: 0.43–0.84) and 95.2% specificity (95% CI: 0.76–0.99) using ELISA. Serum ELISA demonstrated 69.6% sensitivity (95% CI: 0.47–0.87) and 98.4% specificity (95% CI: 0.91–0.99). The stability of DBS in detecting AQP4‐IgG persisted over 24 months for most cases.InterpretationThe DBS represents a viable alternative for detecting AQP4‐IgG in resource‐limited settings to diagnose NMOSD, offering high sensitivity and specificity comparable to serum testing. Moreover, DBS has low shipping costs, is easy to administer, and is suitable for point‐of‐care testing.

Abstract Background Live cell-based assays (CBA) are considered the gold-standard methodology for detecting pathogenic antibodies targeting neural cell surface antigens. However, the adoption of these methods in clinical laboratories has been limited by their manual nature and low throughput. Here, we describe the development and validation of an automated system utilizing a live flow cytometry-based CBA to detect AQP4-IgG. Establishing AQP4-IgG serostatus is a critical component of the diagnostic criteria for Neuromyelitis optica spectrum disorders (NMOSD) as it enables the differentiation of NMOSD from Multiple Sclerosis where there may be significant clinical overlap. The accurate diagnosis of the correct disease state is vital, as the prognosis and treatment approach differ significantly for these two conditions. Two redundant systems were built that automatically receive reagents (live cells in suspension, buffers, diluents, secondary antibodies, and patients’ samples) and generate flow cytometer ready 96-well plates (each containing up to 45 serum or CSF samples tested in duplicate). Methods We assessed the analytical performance of an AQP4-IgG live flow cytometry-based CBA on these new automated systems. We measured intra- and inter-assay imprecision at three levels in 5x5 format and for end-point titer assessment, accuracy (20 positive and 20 negative sera; 5 positive and 5 negative CSF; established on the current manual assay), reference range (20 negative sera and 20 negative CSF from disease controls), analytical sensitivity (LOB and LOD) and specificity (high IgG containing serum specimens), within-plate draft (1 positive sample near the diagnostic cut-off [IgG-binding index of 2.0] that was tested across the entire plate), instrument to instrument correlation (42 positive samples/dilutions tested simultaneously on both systems), and total throughput for both CSF and Serum. Results Imprecision testing yielded the following results: Serum Intra/Inter precision level 1 (IBI = 2) CV% (current method:4.6%/20.7%), (system 1: 3.1%/18.4%), (system 2: 2.6%/22.5%), serum Intra/Inter precision level 2 (IBI=4) CV% (current method:4.9%/23.3%), (system 1: 3.2%/21.9%), (system 2: 2.6%/24.1%), and serum Intra/Inter precision level 3 (IBI =10) pos CV% (current method:6.0%/31.1%), (system 1: 3.8%/27.4%), (system 2: 4.2%/29.4%), and CSF Intra/Inter precision (IBI =2) CV% (System 1: 11.7%/16.8%), (system 2: 6.1%/10.7%). The median end-point titers for all four samples assessed matched within one end-point titer. For accuracy, 100% qualitative agreement between current and both automated systems, and titration accuracy (5 positive serums, 1 positive CSF) all matched within one titer between current and both automated systems. All reference range samples were negative. LOB/LOD in serum (Current: 0.85/1.11), (System 1: 0.82/0.95), (system 2: 0.82/0.96) and CSF (Current: 1.06/1.52), (System 1: 1.02/1.38), (system 2: 1.02/1.64) were comparable. All high IgG samples were negative. Plate drift analysis showed improved whole plate %CV: (Current:6.52%), (system 1: 4.51%), (system 2: 3.46%). Instrument to instrument comparison utilizing linear regression indicated strong agreement across the two systems (slope = 0.93 and R2= 0.95). Assessment of throughput based on real-time timings indicated a maximum output of approximately &gt;700 patient samples per 24hrs per system. Conclusions An automated system for performing live CBAs provides equivalent to superior analytical performance compared to pre-existing manual methods with improved testing capacity.

This cross-sectional study examines the frequency of increased intracranial pressure and its association with myelin oligodendrocyte glycoprotein antibody-associated disease in patients of various ages.

Abstract This post hoc analysis of the randomized, placebo‐controlled N‐MOmentum study (NCT02200770) of inebilizumab in neuromyelitis optica spectrum disorder (NMOSD) evaluated relationships between circulating B‐cell subsets and aquaporin‐4 immunoglobulin G (AQP4‐lgG) titers and attacks. Among participants receiving placebo, CD20 + and CD27 + B‐cell counts were modestly increased from the pre‐attack visit to attack; plasmablast/plasma cell gene signature was increased from baseline to the pre‐attack visit ( p = 0.016) and from baseline to attack ( p = 0.009). With inebilizumab treatment, B‐cell subset counts decreased and did not increase with attacks. No difference in change of AQP4‐IgG titers from baseline to time of attack was observed.

Background: Little is known about the relationship between neighborhood disadvantage and neuromyelitis optica spectrum disorder (NMOSD) outcomes. Objective: The objective is to determine the impact of neighborhood disadvantage on time from symptom onset to diagnosis and annualized relapse rate (ARR). Methods: Neighborhood disadvantage were captured with the Area Deprivation Index (ADI), a validated measure of neighborhood-level disadvantage. Negative binomial regression models assessed the impact of ADI on diagnostic delay (⩾3 months between symptom onset and diagnosis) and ARR. Results: A total of 158 NMOSD patients were identified, a majority of whom were White (56.3%) and female (89.9%) with a mean age of 46 years at diagnosis. The ADI did not significantly affect odds of diagnostic delay (odds ratio (OR) = 0.99, p = 0.26). In univariable models, the ADI was not significantly associated with ARR (OR = 1.004, p = 0.29), but non-White race (OR = 1.541, p = 0.02) and time on immunosuppressive therapies (ISTs; OR = 0.994, p = 0.03) were. White patients used IST for an average of 81% of the follow-up period, compared to an average of 65% for non-White patients ( p < 0.01). Conclusion: No significant relationship between neighborhood-level disadvantage and diagnostic delay or ARR in NMOSD patients was observed. Non-White patients had a higher ARR, which may be related to less IST use.

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