Epileptic seizures of suspected autoimmune origin: a multicentre retrospective study.

OBJECTIVE: To analyse autoantibody status in a well-defined European multicentre cohort of patients with epilepsy of unknown aetiology and to validate the recently proposed Antibody Prevalence in Epilepsy (APE2) and Response to ImmunoTherapy in Epilepsy (RITE2) scores. METHODS: We retrospectively collected clinical and paraclinical data of 92 patients referred to the Neurology Units of Verona and Salzburg between January 2014 and July 2019 with new-onset epilepsy, status epilepticus or chronic epilepsy of unknown aetiology. Fixed and live cell-based assays, tissue-based assays, immunoblot, and live rat hippocampal cell cultures were performed in paired serum/cerebrospinal fluid (CSF) to detect antineuronal and antiglial antibodies. The APE2 and RITE2 scores were then calculated and compared with clinical and laboratory data. RESULTS: Autoantibodies were detected in 29/92 patients (31.5%), with multiple positivity observed in 6/29 cases. The APE2 score (median 5, range 1-15) significantly correlated with antibody positivity (p=0.014), especially for the presence of neuropsychiatric symptoms (p<0.01), movement disorders (p<0.01), dysautonomia (p=0.03), faciobrachial dyskinesias (p=0.03) and cancer history (p<0.01). Status epilepticus was significantly more frequent in antibody-negative patients (p<0.01). Among the items of the RITE2 score, early initiation of immunotherapy correlated with a good treatment response (p=0.001), whereas a cancer history was significantly more common among non-responders (p<0.01). Persistence of neuropsychiatric symptoms and seizures correlated with antiepileptic maintenance after at least 1 year. CONCLUSIONS: This is the first study that independently validates the APE2 and RITE2 scores and includes the largest cohort of patients whose paired serum and CSF samples have been tested for autoantibodies possibly associated with autoimmune epilepsy.

Relevance of antibodies to myelin oligodendrocyte glycoprotein in CSF of seronegative cases.

OBJECTIVE: To determine the diagnostic relevance of myelin oligodendrocyte glycoprotein antibodies (MOG-Abs) in CSF of seronegative cases by retrospectively analyzing consecutive time-matched CSF of 80 MOG-Ab-seronegative patients with demyelinating disease. METHODS: The cohort included 44 patients with NMOSD and related disorders and 36 patients with multiple sclerosis (MS). Two independent neurologists blinded to diagnosis analyzed MOG-Abs by live cell-based immunofluorescence assay with goat anti-human immunoglobulin (Ig) G (whole molecule) antibody. Sera were tested at dilutions of 1:20 and 1:40, and a cutoff of 1:160 was considered for serum positivity. CSF specimens were tested undiluted and at 1:2 dilution with further titrations in case of positivity. Anti-IgG-Fc and anti-IgM-µ secondary antibodies were used to confirm the exclusive presence of MOG-IgG in positive cases. CSF of 13 MOG-Abs seropositive cases and 36 patients with neurodegenerative conditions was analyzed as controls. RESULTS: Three seronegative cases had CSF MOG-Abs (4% of the whole cohort or 7% of cases excluding patients with MS, in which MOG-Abs seem to lack diagnostic relevance). In particular, 2 patients with neuromyelitis optica spectrum disorder (NMOSD) and 1 with acute disseminated encephalomyelitis had MOG-Abs in CSF. Analysis with anti-IgG-Fc and anti-IgM confirmed the exclusive presence of MOG-IgG in the CSF of these patients. Among the control group, MOG-Abs were detectable in the CSF of 8 of 13 MOG-Ab-seropositive cases and in none of the patients with neurodegenerative disorders. CONCLUSION: Although serum is the optimal specimen for MOG-Ab testing, analyzing CSF could improve diagnostic sensitivity in seronegative patients. This observation has relevant diagnostic impact and might provide novel insight into the biological mechanisms of MOG-Ab synthesis.

Distinct serum and cerebrospinal fluid cytokine and chemokine profiles in autoantibody-associated demyelinating diseases.

BACKGROUND: Demyelinating diseases of the central nervous system associated with autoantibodies against aquaporin-4 and myelin-oligodendrocyte-glycoprotein are mediated by different immunopathological mechanisms compared to multiple sclerosis. OBJECTIVE: The purpose of this study was to evaluate serum and cerebrospinal fluid cytokine/chemokine profiles in patients with autoantibodies against aquaporin-4 or autoantibodies against myelin-oligodendrocyte-glycoprotein-associated demyelination compared to multiple sclerosis and autoimmune encephalitis. METHODS: Serum and cerebrospinal fluid cytokine/chemokine levels were analysed using Procartaplex Multiplex Immunoassays. First, we analysed a panel of 32 cytokines/chemokines in a discovery group (nine aquaporin-4-antibody seropositive, nine myelin oligodendrocyte glycoprotein-antibody seropositive, eight encephalitis, 10 multiple sclerosis). Significantly dysregulated cytokines/chemokines were validated in a second cohort (11 aquaporin-4-antibody seropositive, 18 myelin oligodendrocyte glycoprotein-antibody seropositive, 18 encephalitis, 33 multiple sclerosis). RESULTS: We found 11 significantly altered cytokines/chemokines in cerebrospinal fluid and serum samples in the discovery group (a proliferation-inducing ligand, fractalkine=CX3CL1, growth-regulated oncogene-α, interleukin-1 receptor antagonist, interleukin-6, interleukin-8=CXCL8, interleukin-10, interleukin-21, interferon-É£-induced protein-10=CXCL10, monokine induced by interferon-É£=CXCL9, macrophage inflammatory protein-1ß=CCL4). Most of these cytokines/chemokines were up-regulated in autoantibodies against aquaporin-4 or autoantibodies against myelin-oligodendrocyte-glycoprotein positive patients compared to multiple sclerosis. We confirmed these results for cerebrospinal fluid interleukin-6 and serum interleukin-8, growth-regulated oncogene-α, a proliferation-inducing ligand and macrophage inflammatory protein-1ß in the validation set. Receiver-operating characteristic analysis revealed increased levels of cerebrospinal fluid interleukin-6, serum interleukin-8 and growth-regulated oncogene-α in most patients with autoantibody-associated neurological diseases. CONCLUSION: This study suggests that distinctive cerebrospinal fluid and serum cytokine/chemokine profiles are associated with autoantibody-mediated demyelination, but not with multiple sclerosis.

Clinical spectrum and IgG subclass analysis of anti-myelin oligodendrocyte glycoprotein antibody-associated syndromes: a multicenter study.

Anti-myelin oligodendrocyte glycoprotein antibodies (MOG-Ab) recently emerged as a potential biomarker in patients with inflammatory demyelinating diseases of the central nervous system. We here compare the clinical and laboratory findings observed in a cohort of MOG-Ab seropositive and seronegative cases and describe IgG subclass analysis results. Consecutive serum samples referred to Verona University Neuropathology Laboratory for aquaporin-4 (AQP4)-Ab and/or MOG-Ab testing were analysed between March 2014 and May 2017. The presence of AQP4-Ab was determined using a cell-based assay. A live cell immunofluorescence assay was used for the detection of MOG-IgG and IgG subclass analysis. Among 454 analysed samples, 29 were excluded due to AQP4-Ab positivity or to the final demonstration of a disorder not compatible with MOG-Ab. We obtained clinical data in 154 out of 425 cases. Of these, 22 subjects resulted MOG-Ab positive. MOG-Ab positive patients were mainly characterised by the involvement of the optic nerve and/or spinal cord. Half of the cases presented relapses and the recovery was usually partial. Brain MRI was heterogeneous while short lesions were the prevalent observation on spinal cord MRI. MOG-Ab titre usually decreased in non-relapsing cases. In all MOG-IgG positive cases, we observed IgG1 antibodies, which were predominant in most subjects. IgG2 (5/22), IgG3 (9/22) and IgG4 (3/22) antibodies were also detectable. We confirm that MOG-Ab-related syndromes have distinct features in the spectrum of demyelinating conditions, and we describe the possible role of the different IgG subclasses in this condition.