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Gilligan M, McGuigan C, McKeon A. Autoimmune central nervous system disorders: Antibody testing and its clinical utility. Clin Biochem 2024; 126:110746. [PMID: 38462203 PMCID: PMC11016295 DOI: 10.1016/j.clinbiochem.2024.110746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 02/16/2024] [Accepted: 03/05/2024] [Indexed: 03/12/2024]
Abstract
A rapidly expanding repertoire of neural antibody biomarkers exists for autoimmune central nervous system (CNS) disorders. Following clinical recognition of an autoimmune CNS disorder, the detection of a neural antibody facilitates diagnosis and informs prognosis and management. This review considers the phenotypes, diagnostic assay methodologies, and clinical utility of neural antibodies in autoimmune CNS disorders. Autoimmune CNS disorders may present with a diverse range of clinical features. Clinical phenotype should inform the neural antibodies selected for testing via the use of phenotype-specific panels. Both serum and cerebrospinal fluid (CSF) are preferred in the vast majority of cases but for some analytes either CSF (e.g. N-methyl-D-aspartate receptor [NMDA-R] IgG) or serum (e.g. aquaporin-4 [AQP4] IgG) specimens may be preferred. Screening using 2 methods is recommended for most analytes, particularly paraneoplastic antibodies. We utilize murine tissue-based indirect immunofluorescence assay (TIFA) with subsequent confirmatory protein-specific testing. The cellular location of the target antigen informs choice of confirmatory diagnostic assay (e.g. blot for intracellular antigens such as Hu; cell-based assay for cell surface targets such as leucine-rich glioma inactivated 1 [LGI1]). Titers of positive results have limited diagnostic utility with the exception of glutamic acid decarboxylase (GAD) 65 IgG autoimmunity, which is associated with neurological disease at higher values. While novel antibodies are typically discovered using established techniques such as TIFA and immunoprecipitation-mass spectrometry, more recent high-throughput molecular technologies (such as protein microarray and phage-display immunoprecipitation sequencing) may expedite the process of antibody discovery. Individual neural antibodies inform the clinician regarding the clinical associations, oncological risk stratification and tumor histology, the likely prognosis, and immunotherapy choice. In the era of neural antibody biomarkers for autoimmune CNS disorders, access to appropriate laboratory assays for neural antibodies is of critical importance in the diagnosis and management of these disorders.
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Affiliation(s)
- Michael Gilligan
- Departments of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA; Department of Neurology, St Vincent's University Hospital, Dublin, Ireland
| | | | - Andrew McKeon
- Departments of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA; Department of Neurology, Mayo Clinic, Rochester, MN, USA.
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Montalvo M, Flanagan EP. Paraneoplastic/autoimmune myelopathies. HANDBOOK OF CLINICAL NEUROLOGY 2024; 200:193-201. [PMID: 38494277 DOI: 10.1016/b978-0-12-823912-4.00017-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Paraneoplastic myelopathies are a rare but important category of myelopathy. They usually present with an insidious or subacute progressive neurologic syndrome. Risk factors include tobacco use and family history of cancer. Cerebrospinal fluid analysis usually shows lymphocytic pleocytosis with elevated protein. MRI findings suggest that paraneoplastic myelopathies include longitudinally extensive T2 hyperintensities that are tract-specific and accompanied by enhancement, but spinal MRIs can also be normal. The most commonly associated neural antibodies include amphiphysin and collapsin-response-mediator-protein-5 (CRMP5/anti-CV2) antibodies with lung and breast cancers being the most frequent oncologic accompaniments. The differential diagnosis of paraneoplastic myelopathies includes nutritional deficiency myelopathy (B12, copper) as well as autoimmune/inflammatory conditions such as primary progressive multiple sclerosis or spinal cord sarcoidosis. Patients treated with immune checkpoint inhibitors for cancer may develop myelitis, that can be considered along the spectrum of paraneoplastic myelopathies. Management of paraneoplastic myelopathy includes oncologic treatment and immunotherapy. Despite these treatments, the prognosis is poor and the majority of patients eventually become wheelchair-dependent.
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Affiliation(s)
- Mayra Montalvo
- Department of Neurology, University of Florida, Gainesville, FL, United States
| | - Eoin P Flanagan
- Department of Neurology, Mayo Clinic, Rochester, MN, United States; Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States.
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Sun X, Zhao Q, Zhang L, Yuan H. Differences of spinal cord gadolinium enhancement features of neuromyelitis optica spectrum disorder and long-segment degenerative cervical myelopathy. Front Neurol 2023; 14:1191761. [PMID: 37475740 PMCID: PMC10354252 DOI: 10.3389/fneur.2023.1191761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 06/07/2023] [Indexed: 07/22/2023] Open
Abstract
Objectives Neuromyelitis optica spectrum disorder (NMOSD) and long-segment degenerative cervical myelopathy (DCM) may have a similar appearance on MRI. This study aimed to identify the differences in spinal cord gadolinium enhancement features between NMOSD and long-segment DCM. Methods Spinal cord gadolinium enhancement of 27 NMOSD patients and 30 long-segment DCM patients were retrospectively analyzed. Enhancements were evaluated for their number, length, location on the sagittal images, distribution on the axial images, and form on the sagittal images. The Wilcoxon rank sum test was performed to compare numerical variables. The Pearson chi-squared test was performed to compare categorical variables. Results The median number of enhanced lesions (p < 0.05), the median length of the enhancements (p < 0.05), and the location of enhancement on sagittal images (p < 0.05) of NMOSD patients and long-segment DCM patients showed significant differences. The axial distribution of enhancements did not show a significant difference between NMOSD and long-segment DCM patients (p = 0.115). On the sagittal images, linear and ring-formed enhancements were observed in 10 (27.0%) and 17 (63.0%) NMOSD patients, respectively. The enhancements in long-segment DCM patients had a transverse band or pancake-like appearance in 15 (50%) patients and an irregular flake-like appearance with a longitudinally oriented long axis in 15 patients (50%). Conclusion By analyzing the number, length, location, and form of the gadolinium enhancements, NMOSD and long-segment DCM could be well-differentiated.
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Cacciaguerra L, Sechi E, Rocca MA, Filippi M, Pittock SJ, Flanagan EP. Neuroimaging features in inflammatory myelopathies: A review. Front Neurol 2022; 13:993645. [PMID: 36330423 PMCID: PMC9623025 DOI: 10.3389/fneur.2022.993645] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 08/16/2022] [Indexed: 11/15/2022] Open
Abstract
Spinal cord involvement can be observed in the course of immune-mediated disorders. Although multiple sclerosis (MS) represents the leading cause of inflammatory myelopathy, an increasing number of alternative etiologies must be now considered in the diagnostic work-up of patients presenting with myelitis. These include antibody-mediated disorders and cytotoxic T cell-mediated diseases targeting central nervous system (CNS) antigens, and systemic autoimmune conditions with secondary CNS involvement. Even though clinical features are helpful to orient the diagnostic suspicion (e.g., timing and severity of myelopathy symptoms), the differential diagnosis of inflammatory myelopathies is often challenging due to overlapping features. Moreover, noninflammatory etiologies can sometimes mimic an inflammatory process. In this setting, magnetic resonance imaging (MRI) is becoming a fundamental tool for the characterization of spinal cord damage, revealing a pictorial scenario which is wider than the clinical manifestations. The characterization of spinal cord lesions in terms of longitudinal extension, location on axial plane, involvement of the white matter and/or gray matter, and specific patterns of contrast enhancement, often allows a proper differentiation of these diseases. For instance, besides classical features, such as the presence of longitudinally extensive spinal cord lesions in patients with aquaporin-4-IgG positive neuromyelitis optica spectrum disorder (AQP4+NMOSD), novel radiological signs (e.g., H sign, trident sign) have been recently proposed and successfully applied for the differential diagnosis of inflammatory myelopathies. In this review article, we will discuss the radiological features of spinal cord involvement in autoimmune disorders such as MS, AQP4+NMOSD, myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), and other recently characterized immune-mediated diseases. The identification of imaging pitfalls and mimics that can lead to misdiagnosis will also be examined. Since spinal cord damage is a major cause of irreversible clinical disability, the recognition of these radiological aspects will help clinicians achieve a correct and prompt diagnosis, treat early with disease-specific treatment and improve patient outcomes.
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Affiliation(s)
- Laura Cacciaguerra
- Department of Neurology, Mayo Clinic, Rochester, MN, United States
- Neuroimaging Research Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
- Vita-Salute San Raffaele University, Milan, Italy
| | - Elia Sechi
- Neurology Unit, Department of Medical, Surgical and Experimental Sciences, University of Sassari, Sassari, Italy
| | - Maria A. Rocca
- Neuroimaging Research Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
- Vita-Salute San Raffaele University, Milan, Italy
- Neurology Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Massimo Filippi
- Neuroimaging Research Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
- Vita-Salute San Raffaele University, Milan, Italy
- Neurology Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy
- Neurorehabilitation Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy
- Neurophysiology Service, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Sean J. Pittock
- Department of Neurology, Mayo Clinic, Rochester, MN, United States
- Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
| | - Eoin P. Flanagan
- Department of Neurology, Mayo Clinic, Rochester, MN, United States
- Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
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