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Objective: The contemporary diagnosis of paraneoplastic neurologic syndromes (PNSs) requires an increasing understanding of their clinical, immunologic, and oncologic heterogeneity. The 2004 PNS criteria are partially outdated due to advances in PNS research in the last 16 years leading to the identification of new phenotypes and antibodies that have transformed the diagnostic approach to PNS. Here, we propose updated diagnostic criteria for PNS., Methods: A panel of experts developed by consensus a modified set of diagnostic PNS criteria for clinical decision making and research purposes. The panel reappraised the 2004 criteria alongside new knowledge on PNS obtained from published and unpublished data generated by the different laboratories involved in the project., Results: The panel proposed to substitute "classical syndromes" with the term "high-risk phenotypes" for cancer and introduce the concept of "intermediate-risk phenotypes." The term "onconeural antibody" was replaced by "high risk" (>70% associated with cancer) and "intermediate risk" (30%-70% associated with cancer) antibodies. The panel classified 3 levels of evidence for PNS: definite, probable, and possible. Each level can be reached by using the PNS-Care Score, which combines clinical phenotype, antibody type, the presence or absence of cancer, and time of follow-up. With the exception of opsoclonus-myoclonus, the diagnosis of definite PNS requires the presence of high- or intermediate-risk antibodies. Specific recommendations for similar syndromes triggered by immune checkpoint inhibitors are also provided., Conclusions: The proposed criteria and recommendations should be used to enhance the clinical care of patients with PNS and to encourage standardization of research initiatives addressing PNS., (Copyright © 2021 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.)

Objective: To describe the clinical characteristics and outcomes of coronavirus disease 2019 (COVID-19) among patients with myasthenia gravis (MG) and identify factors associated with COVID-19 severity in patients with MG., Methods: The CO-MY-COVID registry was a multicenter, retrospective, observational cohort study conducted in neuromuscular referral centers and general hospitals of the FILNEMUS (Filière Neuromusculaire) network (between March 1, 2020, and June 8, 2020), including patients with MG with a confirmed or highly suspected diagnosis of COVID-19. COVID-19 was diagnosed based on a PCR test from a nasopharyngeal swab or severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serology, thoracic CT scan, or typical symptoms. The main outcome was COVID-19 severity based on location of treatment/management (home, hospitalized in a medical unit, or in an intensive care unit). We collected information on demographic variables, general history, and risk factors for severe COVID-19. Multivariate ordinal regression models were used to identify factors associated with severe COVID-19 outcomes., Results: Among 3,558 patients with MG registered in the French database for rare disorders, 34 (0.96%) had COVID-19. The mean age at COVID-19 onset was 55.0 ± 19.9 years (mean MG duration: 8.5 ± 8.5 years). By the end of the study period, 28 patients recovered from COVID-19, 1 remained affected, and 5 died. Only high Myasthenia Gravis Foundation of America (MGFA) class (≥IV) before COVID-19 was associated with severe COVID-19 ( p = 0.004); factors that were not associated included sex, MG duration, and medium MGFA classes (≤IIIb). The type of MG treatment had no independent effect on COVID-19 severity., Conclusions: This registry-based cohort study shows that COVID-19 had a limited effect on most patients, and immunosuppressive medications and corticosteroids used for MG management are not risk factors for poorer outcomes. However, the risk of severe COVID-19 is elevated in patients with high MGFA classes (odds ratio, 102.6 [4.4-2,371.9]). These results are important for establishing evidence-based guidelines for the management of patients with MG during the COVID-19 pandemic., (© 2021 American Academy of Neurology.)

Objective: To discover systemic characteristics in the repertoires of targeted autoantigens in chronic inflammatory demyelinating polyneuropathy (CIDP), we detected the entire autoantigen repertoire of patients and controls and analyzed them systematically., Methods: We screened 43 human serum samples, of which 22 were from patients with CIDP, 12 from patients with other neuropathies, and 9 from healthy controls via HuProt Human Proteome microarrays testing about 16,000 distinct human bait proteins. Autoantigen repertoires were analyzed via bioinformatical autoantigenomic approaches: principal component analysis, analysis of the repertoire sizes in disease groups and clinical subgroups, and overrepresentation analyses using Gene Ontology and PantherDB., Results: The autoantigen repertoires enabled the identification of a subgroup of 10/22 patients with CIDP with a younger age at onset and a higher frequency of mixed motor and sensory CIDP. IV immunoglobulin therapy responders targeted 3 times more autoantigens than nonresponders. No CIDP-specific autoantibody is present in all patients; however, anchoring junction components were significantly targeted by 86.4% of patients with CIDP. There are potential novel CIDP-specific autoantigens such as the myelination- or axo-glial structure-related proteins actin-related protein 2/3 complex subunit 1B, band 4.1-like protein 2, cadherin-15, cytohesin-1, epidermal growth factor receptor, ezrin, and radixin., Conclusions: The repertoire of targeted autoantigens of patients with CIDP differs in a systematic degree from those of controls. Systematic autoantigenomic approaches can help to understand the disease and to discover novel bioinformatical tools and novel autoantigen panels to improve diagnosis, treatment, prognosis, or patient stratification., (Copyright © 2021 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.)

CANOMAD (chronic ataxic neuropathy, ophthalmoplegia, immunoglobulin M [IgM] paraprotein, cold agglutinins, and disialosyl antibodies) is a rare syndrome characterized by chronic neuropathy with sensory ataxia, ocular, and/or bulbar motor weakness in the presence of a monoclonal IgM reacting against gangliosides containing disialosyl epitopes. Data regarding associated hematologic malignancies and effective therapies in CANOMAD are scarce. We conducted a French multicenter retrospective study that included 45 patients with serum IgM antibodies reacting against disialosyl epitopes in the context of evocating neurologic symptoms. The main clinical features were sensitive symptoms (ataxia, paresthesia, hypoesthesia; n = 45, 100%), motor weakness (n = 18, 40%), ophthalmoplegia (n = 20, 45%), and bulbar symptoms (n = 6, 13%). Forty-five percent of the cohort had moderate to severe disability (modified Rankin score, 3-5). Cold agglutinins were identified in 15 (34%) patients. Electrophysiologic studies showed a demyelinating or axonal pattern in, respectively, 60% and 27% of cases. All patients had serum monoclonal IgM gammopathy (median, 2.6 g/L; range, 0.1-40 g/L). Overt hematologic malignancies were diagnosed in 16 patients (36%), with the most frequent being Waldenström macroglobulinemia (n = 9, 20%). Forty-one patients (91%) required treatment of CANOMAD. Intravenous immunoglobulins (IVIg) and rituximab-based regimens were the most effective therapies with, respectively, 53% and 52% of partial or better clinical responses. Corticosteroids and immunosuppressive drugs were largely ineffective. Although more studies are warranted to better define the optimal therapeutic sequence, IVIg should be proposed as the standard of care for first-line treatment and rituximab-based regimens for second-line treatment. These compiled data argue for CANOMAD to be included in neurologic monoclonal gammopathy of clinical significance., (© 2020 by The American Society of Hematology.)

Objective: To describe the main syndrome and clinical course in a large cohort of patients with anti-Ri-associated paraneoplastic neurologic syndrome (Ri-PNS)., Methods: Twenty-year retrospective nationwide study and systematic review of the literature., Results: Thirty-six patients with complete clinical information were identified (median age 66 years, range: 47-87 years). In this French cohort, the majority were women (78%). At onset, 4 main patterns were observed: cerebellar syndrome (39%), isolated tremor (24%), oculomotor disturbances (17%), and other symptoms (19%). Course was multistep for 78% of cases. At the time the disease reached the plateau phase (median 12 weeks, range: 1-64 weeks; 28% >3 months), 24 (67%) showed an overt cerebellar syndrome, which was isolated in 3 patients, and was most frequently (21/24 cases) part of a multisystem neurologic disease. Patients manifested a variety of movement disorders, including myoclonus (33%), dystonia (17%), either cervical or oromandibular, and parkinsonism (17%). Most patients had cancer (92%), mainly breast cancer (n = 22). Misdiagnoses concerned 22% of patients (n = 8) and included atypical parkinsonism (n = 2), MS (n = 2), Bickerstaff encephalitis (n = 1), hyperekplexia (n = 1), vestibular neuritis (n = 1), and functional neurologic disorder (n = 1). Survival at 12 months was 73% (95% CI [0.54-0.85]), at 24 months 62% (95% CI [0.41-0.78]), and at 36 months 47% (95% CI [0.25-0.65]). There was no major clinical difference between cases retrieved from the systematic review of the literature (n = 55) and the French cohort., Conclusions: Ri-PNS is a multisystem neurologic syndrome with prominent cerebellum/brainstem involvement. Opsoclonus-myoclonus is less common than expected, and the disorder can mimic neurodegenerative diseases., (Copyright © 2020 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.)

Objective: The aim of this study was to evaluate whether mutations in ERLIN2 , known to cause SPG18, a recessive hereditary spastic paraplegia (SP) responsible for the degeneration of the upper motor neurons leading to weakness and spasticity restricted to the lower limbs, could contribute to amyotrophic lateral sclerosis (ALS), a distinct and more severe motor neuron disease (MND), in which the lower motor neurons also profusely degenerates, leading to tetraplegia, bulbar palsy, respiratory insufficiency, and ultimately the death of the patients., Methods: Whole-exome sequencing was performed in a large cohort of 200 familial ALS and 60 sporadic ALS after a systematic screening for C9orf72 hexanucleotide repeat expansion. ERLIN2 variants identified by exome analysis were validated using Sanger analysis. Segregation of the identified variant with the disease was checked for all family members with available DNA., Results: Here, we report the identification of ERLIN2 mutations in patients with a primarily SP evolving to rapid progressive ALS, leading to the death of the patients. These mutations segregated with the disease in a dominant (V168M) or recessive (D300V) manner in these families or were found in apparently sporadic cases (N125S)., Conclusions: Inheritance of ERLIN2 mutations appears to be, within the MND spectrum, more complex that previously reported. These results expand the clinical phenotype of ERLIN2 mutations to a severe outcome of MND and should be considered before delivering a genetic counseling to ERLIN2 -linked families., (Copyright © 2019 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.)

Purpose: Identifying autoantigens of serological autoantibodies requires expensive methods, such as protein microarrays or IP+MS. Thus, sera are commonly pre-screened for interesting immunopatterns via immunocytochemistry/immunohistochemistry. However, distinguishing immunopatterns can be difficult and intracellular antigens are less accessible. Therefore, a simple and cheap immunoblot screening able to distinguish immunopatterns and to detect refractory proteins is presented., Experimental Design: Five steps of immunoblotting-based autoantigen screening are revised: (1) choice of protein source, (2) protein extraction, (3) protein separation, (4) protein transfer, (5) antigen detection. Thereafter, 52 patients' sera with chronic inflammatory demyelinating polyneuropathy (CIDP) and 45 controls were screened., Results: The protein source impacts the detected antigen set. Steps 2-4 can be adapted for refractory proteins. Furthermore, longitudinal cutting of protein lanes saves ≥75% of time and material and allows for exact comparison of band patterns. As the latter are individually specific and temporarily constant, we call them "immunological fingerprints". In a proof-of-principle, a 155 kDa immunoband was detected with two anti-neurofascin-155-positive CIDP sera and two further immunobands (120/220 kDa) specific to a subgroup of 3-6 of 52 CIDP patients., Conclusions and Clinical Relevance: Adapted immunoblotting is a cheap and simple method for accurate serum screening including refractory and intracellular antigens., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Objective: To report the clinical features and long-term outcome of 22 newly diagnosed paraneoplastic patients with GABA B receptor antibodies (GABA B R-Abs)., Methods: Retrospective clinical study of CSF-confirmed cases of GABA B R-Abs encephalitis., Results: We identified 22 patients (4 female) with GABA B R-Abs, with a median age of 64 years (range 55-85). All were paraneoplastic: 20 small-cell lung cancer, one malignant thymoma, and one uncharacterized lung mass. The most frequent first symptom was the isolated recurrent seizures without cognitive inter-ictal impairment in 17 patients (77%). In the other, three presented the first behavioral disorders and two presented de novo status epilepticus (SE). After a median delay of 10 days (range 1-30), the recurrent seizures' phase was followed by an encephalitic phase characterized by confusion in 100% of cases and SE in 81% (n = 17), with 53% (n = 9) non-convulsive SE. Dysautonomic episodes were frequent (36%, n = 8, bradycardia and central apnea) and killed three patients. CSF study was abnormal in 95% of the cases (n = 21). At the encephalitic phase, MRI showed a temporal FLAIR hypersignal in 73% (n = 16) of the cases. First-line immunotherapy was initiated after a median delay of 26 days (range 6-65) from disease onset, and a partial response was observed in 10 out of 20 patients (50%). There was no complete response. Two years after onset, a massive anterograde amnesia affected all still alive patients. Nine patients died from cancer progression (median survival: 1.2 years)., Conclusion: Paraneoplastic GABA B R-Abs encephalitis is characterized by a stereotype presentation with an epilepsy phase before an encephalitic phase with dysautonomia. The functional prognosis is poor.

Objective: The aim of this study was to describe specificities of patients with NMDA receptor antibody (NMDAR-Ab) encephalitis associated with a malignant tumor., Methods: Retrospective observational study of 252 patients with NMDAR-Ab encephalitis of the French Paraneoplastic Neurological Syndrome Reference Center. Patients were classified in three groups: (1) non-malignant ovarian teratomas, (2) malignant ovarian teratomas (immature), and (3) other malignant tumors., Results: Sixty patients (23.8%) had an associated tumor and 15 (6%) were malignant. No particular neurological symptom was observed in these patients. Ovarian teratomas were the most frequent (51 cases) with 6 of them immature (11.8% of teratomas). Nine patients (3.6%) developed other malignant tumors (3 small cell lung carcinomas, 1 uterine adenocarcinoma, 1 prostate adenocarcinoma, 1 Hodgkin lymphoma, 1 pineal dysgerminoma, 1 neuroblastoma and 1 pancreatic neuroendocrine tumor). Among patients with a cancer other than teratoma, 6/9 were elderly patients (median age 65 years, representing 30% of elderly patients with such encephalitis) compared to a median age of 26 years in adult patients included herein. The clinical course was similar in the three groups, other than a higher death rate among patients with malignant tumors (86 versus 2%; p < 0.001) mainly due to tumor progression (5/7 deaths)., Conclusion: Immature ovarian teratomas represent 11.8% of all teratomas in patients with NDMAR-Ab encephalitis. The other malignant tumors are mainly observed in elderly patients. The presence of a malignant tumor does not impact the neurological presentation but is directly associated with a higher risk of death.

Objective: To report the clinical features of 11 patients with metabotropic glutamate receptor 5 (mGluR5) antibody-associated encephalitis, immunoglobulin G (IgG) subclass, and effects of the antibodies on neuronal mGluR5 clusters., Methods: Clinical information was retrospectively obtained from referring physicians. Antibodies to mGluR5 and IgG subclasses were determined with brain immunohistochemistry and cell-based assays. The effects of the antibodies were examined on rat hippocampal neurons with reported techniques., Results: From January 2005 to May 2017, 11 patients (median age 29 years, range 6-75 years, 5 female) were identified. The main clinical features were psychiatric (10), cognitive (10), movement disorders (7), sleep dysfunction (7), and seizures (6). Median modified Rankin Scale score at the peak of the disease was 4; 4 patients required intensive care. Five patients had Hodgkin lymphoma, and 1 had small cell lung cancer. CSF showed pleocytosis (median white blood cell count 22 mm 3 ) in all patients; brain MRI was abnormal in 5, involving limbic (1) or extralimbic (4) regions. Treatments included immunotherapy and/or oncologic therapy; at the last follow-up (median 48 months), 6 patients had complete and 5 had partial recovery. Neurologic relapse occurred in 2 patients. Antibodies were IgG1 alone (4 of 9) or in combination with IgG2 (1 of 9), IgG3 (3 of 9), or both (1). Patients' IgG caused a significant and specific decrease of cell-surface synaptic and extrasynaptic mGluR5 without altering the levels of postsynaptic density protein 95., Conclusions: Anti-mGluR5 encephalitis associates with a complex neuropsychiatric syndrome, not restricted to limbic encephalitis, and can occur without tumor. Patients respond to treatment, but relapses can occur. The antibodies have pathogenic effects altering the levels of cell-surface mGluR5., (© 2018 American Academy of Neurology.)

Purpose of Review: To review recent advances in paraneoplastic neuropathies with emphasis on their definition, different forms and therapeutic development., Recent Findings: A strict definition of definite paraneoplastic neuropathies is necessary to avoid confusion. With carcinoma, seronegative sensory neuronopathies and neuronopathies and anti-Hu and anti-CV2/Contactin Response Mediator Protein 5 antibodies are the most frequent. With lymphomas, most neuropathies occur with monoclonal gammopathy including AL amyloidosis, Polyneuropathy-Organomegaly-Endocrinopathy-M component-Skin changes (POEMS) syndrome, type I cryoglobulinemia and antimyelin-associated glycoprotein (MAG) neuropathies and Waldenström's disease. Neuropathies improving with tumor treatment are occasional, occur with a variety of cancer and include motor neuron disease, chronic inflammatory demyelinating neuropathy and nerve vasculitis. If antibodies toward intracellular antigens are well characterized, it is not the case for antibodies toward cell membrane proteins. Contactin-associated protein-2 antibodies occur with neuromyotonia and thymoma with the Morvan's syndrome in addition to Netrin 1 receptor antibodies but may not be responsible for peripheral nerve hyperexcitability. The treatment of AL amyloidosis, POEMS syndrome, anti-MAG neuropathy and cryoglobulinemia is now relatively well established. It is not the case with onconeural antibodies for which the rarity of the disorders and a short therapeutic window are limiting factors for the development of clinical trials., Summary: A strict definition of paraneoplastic neuropathies helps their identification and is necessary to allow an early diagnosis of the underlying tumor.

Introduction: Morbidity and mortality of Herpes simplex virus encephalitis (HSE) remain high. Relapses of neurological signs may occur after initial clinical improvement under acyclovir treatment., Methods: We report here a case of post-HSE anti-N-methyl-d-aspartate receptor-mediated encephalitis in an adult and perform a systematic search on PubMed to identify other cases in adults., Results: We identified 11 previously published cases, to discuss diagnostic and therapeutic management. Symptoms in adults are often inappropriate behaviors, confusion and agitation. Diagnosis of anti-NMDA-R encephalitis after HSE is often delayed. Treatment consists in steroids, plasma exchange, and rituximab. Prognosis is often favorable., Conclusion: Anti-NMDA-R antibodies should be searched in cerebrospinal fluid of patients with unexpected evolution of HSE. This emerging entity reopens the hot debate about steroids in HSE.

Objective: To report paroxysmal episodes of cerebellar ataxia in a patient with anti-contactin-associated protein-like 2 (CASPR2) antibody-related autoimmune encephalitis and to search for similar paroxysmal ataxia in a cohort of patients with anti-CASPR2 antibody-associated autoimmune encephalitis., Methods: We report a patient with paroxysmal episodes of cerebellar ataxia observed during autoimmune encephalitis with anti-CASPR2 antibodies. In addition, clinical analysis was performed in a retrospective cohort of 37 patients with anti-CASPR2 antibodies to search for transient episodes of ataxia. Paroxysmal symptoms were further specified from the referral physicians, the patients, or their relatives., Results: A 61-year-old man with limbic encephalitis and anti-CASPR2 antibodies developed stereotyped paroxysmal episodes of cerebellar ataxia, including gait imbalance, dysarthria, and dysmetria, 1 month after the onset of the encephalitis. The ataxic episodes were specifically triggered by orthostatism and emotions. Both limbic symptoms and transient ataxic episodes resolved after treatment with steroids and IV cyclophosphamide. Among 37 other patients with anti-CASPR2 antibodies, we identified 5 additional cases with similar paroxysmal ataxic episodes that included gait imbalance (5 cases), slurred speech (3 cases), limb dysmetria (3 cases), and nystagmus (1 case). All had concomitant limbic encephalitis. Paroxysmal ataxia was not observed in patients with neuromyotonia or Morvan syndrome. Triggering factors (orthostatism or anger) were reported in 4 patients. Episodes resolved with immunomodulatory treatments in 4 patients and spontaneously in 1 case., Conclusions: Paroxysmal cerebellar ataxia must be added to the spectrum of the anti-CASPR2 antibody syndrome.

Objective: To report 10 patients with limbic encephalitis (LE) and adenylate kinase 5 autoantibodies (AK5-Abs)., Methods: We conducted a retrospective study in a cohort of 50 patients with LE with uncharacterized autoantibodies and identified a specific target using immunohistochemistry, Western blotting, immunoprecipitation, mass spectrometry, and cell-based assay., Results: AK5 (a known autoantigen of LE) was identified as the target of antibodies in the CSFs and sera of 10 patients with LE (median age 64 years; range 57-80), which was characterized by subacute anterograde amnesia without seizure and sometimes preceded by a prodromal phase of asthenia or mood disturbances. Anterograde amnesia can be isolated, but some patients also complained of prosopagnosia, paroxysmal anxiety, or abnormal behavior. No associated cancer was observed. All 10 patients had bilateral hippocampal hypersignal on a brain MRI. CSF analysis generally showed a mild pleiocytosis with elevated immunoglobulin G index and oligoclonal bands, as well as high levels of tau protein with normal concentration of Aβ42 and phospho-tau, suggesting a process of neuronal death. Except for one patient, clinical response to immunotherapy was unfavorable, with persistence of severe anterograde amnesia. Two patients evolved to severe cognitive decline. Hippocampal atrophy was observed on control brain MRI. Using in vitro tests on hippocampal neurons, we did not identify clues suggesting a direct pathogenic role of AK5-Abs., Conclusions: AK5-Abs should be systematically considered in aged patients with subacute anterograde amnesia. Recognition of this disorder is important to develop new treatment strategies to prevent irreversible limbic damage., (© 2017 American Academy of Neurology.)

Objective: To precisely describe the initial psychiatric presentation of patients with anti-NMDA receptor (NMDAR) antibodies encephalitis (anti-NMDAR encephalitis) to identify potential clues enhancing its early diagnosis., Methods: We retrospectively studied the French Reference Centre medical records of every adult patient with anti-NMDAR encephalitis to specify the patients' initial psychiatric symptoms leading to hospitalization in a psychiatric department and the reasons underlying the diagnosis of anti-NMDAR encephalitis., Results: The medical records of 111 adult patients were reviewed. Psychiatric features were the initial presentation in 65 patients (59%). Among them, several psychiatric manifestations were observed, including visual and auditory hallucinations (n = 26, 40%), depression (n = 15, 23%), mania (n = 5, 8%), acute schizoaffective episode (n = 15, 23%), and eating disorder or addiction (n = 4; 6%). Forty-five patients (40% of total cohort) were first hospitalized in a psychiatric institution (91% women), with a median duration of stay of 9 days (range 0.25-239 days). Among them, 24 patients (53%) had associated discreet neurologic signs at the first evaluation, while 17 additional patients (38%) developed neurologic signs within a few days. Twenty-one patients (47%) were transferred to a medical unit for a suspicion of antipsychotic intolerance characterized by high temperature, muscle rigidity, mutism or coma, and biological results suggesting rhabdomyolysis., Conclusions: Several psychiatric presentations were observed in patients with anti-NMDAR encephalitis, although none was specific; however, patients, mostly women, also had discreet neurologic signs that should be carefully assessed as well as signs of antipsychotic intolerance that should raise suspicion for anti-NMDAR encephalitis.

Background: Immunological mechanisms are suspected in sensory neuropathy (SN) occurring with systemic autoimmune diseases and in some idiopathic cases, but so far there are no antibodies (Abs) identifying these neuropathies., Methods: In the search for such specific antibodies, serum samples were collected from 106 patients with SN of these 72 fulfilled the diagnosis criteria of sensory neuronopathy (SNN) and 211 control subjects including patients with sensorimotor neuropathies, other neurological diseases (ONDs), systemic autoimmune diseases and healthy blood donors., Results: In the first step, a protein array with 8000 human proteins allowed identification of the intracellular domain of the fibroblast growth factor receptor 3 (FGFR3) as a target of Abs in 7/16 SNN and 0/30 controls. In the second step, an ELISA method was used to test the 317 patients and controls for anti-FGFR3 Abs. Abs were detected in 16/106 patients with SN and 1/211 controls (p<0.001). Among the 106 patients with SN, anti-FGFR3 Abs were found in 11/38 patients with autoimmune context, 5/46 with idiopathic neuropathy and 0/22 with neuropathy of other aetiology (p=0.006). The only control patient with anti-FGFR3 Abs had lupus and no recorded neuropathy. Sensitivity, specificity, and positive and negative predictive values of anti-FGFR3 Abs for a diagnosis of idiopathic or dysimmune SN were 19%, 99.6%, 94.1% and 77.3%, respectively. A cell-based assay confirmed serum reactivity against the intracellular domain of FGFR3. The neuropathy in patients with anti-FGF3 Abs was non-length dependent in 87% of patients and fulfilled the criteria of probable SNN in 82%. Trigeminal nerve involvement and pain were frequent features., Conclusions: A anti-FGFR3 Abs identify a subgroup of patients with SN in whom an underlying autoimmune disorder affecting sensory neurons in the dorsal root and trigeminal nerve ganglia is suspected., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/)

Objective: To evaluate the presence of immunoglobulin A (IgA) subtype of anti-NMDA receptor (NMDAR) antibodies (IgA-NMDAR-Abs) in the CSF of patients with immunoglobulin G (IgG)-NMDAR-Ab encephalitis and to describe the potential association with a specific clinical pattern., Methods: The retrospective analysis for the presence of IgA-NMDAR-Abs in 94 CSF samples from patients with anti-NMDAR encephalitis diagnosed between October 2007 and February 2014 was conducted at the French Reference Centre on Paraneoplastic Neurological Syndrome. This observational study compared 39 patients with both IgA- and IgG-NMDAR-Abs to 55 patients with only IgG-NMDAR-Abs., Results: In the retrospective cohort, 41% of the patients with NMDAR-Ab encephalitis had both CSF IgG- and IgA-NMDAR-Abs. Approximately half of the IgA-NMDAR-Ab-positive patients (18/38, 49%) definitively possessed associated tumors, primarily ovarian teratomas (17/18, 94%), compared with only 5% (3/55) of the patients in the IgA-NMDAR-Ab-negative group (p < 0.001). In the adult female population at risk for ovarian teratoma, the detection of CSF IgA-NMDAR-Ab positivity showed 85% sensitivity, 70% specificity, a 57% positive predictive value, and a 90% negative predictive value for the diagnosis of ovarian teratoma. No other specific clinical features or clinical outcome were associated with CSF IgA-NMDAR-Ab positivity., Conclusion: These results suggest that in patients with IgG-NMDAR-Ab encephalitis, CSF IgA-NMDAR-Abs could be used as a biological marker for the presence of an ovarian teratoma.

Importance: The clinical features of autoimmune encephalitis associated with antibodies against the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR-Abs) remain poorly defined., Objectives: To describe 7 patients with encephalitis and AMPAR-Abs and to provide a review of the literature on this disease entity., Design, Setting, and Participants: The setting was the Centre National de Référence pour les Syndromes Neurologiques Paranéoplasiques (Lyon, France), and participants were 7 consecutive patients diagnosed as having encephalitis and AMPAR-Abs between January 1, 2010, and December 1, 2014. Patients' clinical data were analyzed, with a median follow-up period of 12 months (range, 2-31 months). Relevant articles were identified in the MEDLINE database using the keywords autoimmune encephalitis and AMPA receptor antibodies until February 15, 2015., Main Outcomes and Measures: Modes of onset, full clinical presentations, and cancer prevalence., Results: The patients included 4 women and 3 men (median age, 56 years). Four main modes of encephalitis onset were observed, including confusion (3 patients), epileptic (1 patient), amnestic (1 patient), and a severe form of fulminant encephalitis (2 patients). In contrast with previous reports, we observed only 1 patient with seizures. Two patients had cancer (1 lung carcinoma and the other thymic carcinoma). Analysis of the literature identified 35 published cases of encephalitis and AMPAR-Abs, including 18 with clinical data. The same modes of encephalitis onset were observed, including confusion (12 patients), epileptic (1 patient), amnestic (3 patients), and fulminant encephalitis (2 patients). Eleven patients were initially seen with a neoplasm (lung, breast, thymoma, or ovary)., Conclusions and Relevance: The clinical spectrum of AMPAR encephalitis is variable. Cancer was found in 13 of 27 patients (48%) with known cancer status. Most patients are seen with symptoms suggestive of autoimmune limbic encephalitis, although they can be paucisymptomatic or may manifest severe panencephalitis that evolves to a minimally conscious state and diffuse cortical atrophy. Patients suspected of having autoimmune encephalitis should undergo screening for serum and cerebrospinal fluid AMPAR-Abs.

Objective: To assess the efficacy and safety of intraveinous immunoglobulin (IV Ig) in patients with chronic inflammatory demyelinating polyneuropathy (CIDP) at 4, 7 and 12months., Methods: A national multicenter retrospective study was conducted by LFB Biotehcnologies in patients with CIDP who had received at least one cycle of a 5% polyvalent IV Ig, Tegeline(®), from LFB biomédicaments between 1995 and 2004. The primary endpoint was the efficacy of IV Ig at 4 months, which was defined as the responder rate based on the modified Rankin scale. Several secondary endpoints were assessed: safety and efficacy (i.e., responders according to the investigators' overall assessment of the patients' status) at 4, 7 and 12 months. The analysis was performed at 7 months only (due to missing data for 12 months and few patients)., Results: A total of 26 patients were included who had received between 1 and 6 cycles of IV Ig (mean 3±2) with a median follow-up of 9.9 months. The responder rate at 4 months based on the modified Rankin scale was 52% (95% CI 0.313-0.722), whereas the responder rate with placebo reported in the literature (meta-analysis including results from van Schaik and an ICE study) is 18% (P<0.001). Responder patients at 4 months were still responders at 7 months. The overall safety of IV Ig was good, with adverse events of mild to moderate severity, which resolved without sequelae and were expected adverse events of IV Ig., Conclusion: This retrospective study confirmed both the efficacy of IV Ig at 4 months in the treatment of chronic inflammatory demyelinating polyneuropathy and the favorable safety profile of the product., (Copyright © 2015 Elsevier Masson SAS. All rights reserved.)

There are no validated criteria for the diagnosis of sensory neuronopathy (SNN) yet. In a preliminary monocenter study a set of criteria relying on clinical and electrophysiological data showed good sensitivity and specificity for a diagnosis of probable SNN. The aim of this study was to test these criteria on a French multicenter study. 210 patients with sensory neuropathies from 15 francophone reference centers for neuromuscular diseases were included in the study with an expert diagnosis of non-SNN, SNN or suspected SNN according to the investigations performed in these centers. Diagnosis was obtained independently from the set of criteria to be tested. The expert diagnosis was taken as the reference against which the proposed SNN criteria were tested. The set relied on clinical and electrophysiological data easily obtainable with routine investigations. 9/61 (16.4 %) of non-SNN patients, 23/36 (63.9 %) of suspected SNN, and 102/113 (90.3 %) of SNN patients according to the expert diagnosis were classified as SNN by the criteria. The SNN criteria tested against the expert diagnosis in the SNN and non-SNN groups had 90.3 % (102/113) sensitivity, 85.2 % (52/61) specificity, 91.9 % (102/111) positive predictive value, and 82.5 % (52/63) negative predictive value. Discordance between the expert diagnosis and the SNN criteria occurred in 20 cases. After analysis of these cases, 11 could be reallocated to a correct diagnosis in accordance with the SNN criteria. The proposed criteria may be useful for the diagnosis of probable SNN in patients with sensory neuropathy. They can be reached with simple clinical and paraclinical investigations.

Sensory neuronopathy (SNN) depends on a pathophysiological process that targets the sensory neuron in the posterior root ganglia. These rare diseases are sometimes difficult to diagnose because the site of impairment is not directly assessable by conventional neurophysiological techniques. After recalling the general data concerning SNN, we propose an easy to use clinical and electrophysiological diagnosis criteria and guidelines for clinicians in their search for an etiology in a patient with NNS., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

Paraneoplastic neurological syndromes are rare but can affect any part of the peripheral nervous system (PNS) including motor neurons, sensory ganglia, nerve roots, plexuses, cranial and peripheral nerves, and neuromuscular junctions. The type of cancer, lymphoma or solid tumour, is a determinant factor of the underlying mechanism. With solid tumour, antibodies directed to intracellular (anti-Hu or anti-CV2/CRMP5 antibodies) or surface antigens (anti-VGCC,or LGI1 and Caspr2 antibodies) have been identified while with lymphoma, the neuropathy is usually linked to a monoclonal gammopathy. This review discusses the different etiologies and mechanisms of paraneoplastic disorders of the PNS in patients emphasising their evaluation, diagnosis and treatment., (Copyright © 2013 Elsevier Masson SAS. All rights reserved.)

Objective: Intracranial hemorrhage (ICH) is an antithrombotic treatment complication. Our study's goal is to assess the proportion of ICH occurring while the patient is on antithrombotic treatment. The secondary goal is to assess the proportion of "avoidable" ICH (anticoagulant overdosage, debatables indications)., Methods: We conducted a descriptive epidemiological single-center study of ICH during 2 years. We analyzed the type of ICH, the type of antithrombotic treatment, the level of anticoagulation and the relevance of antithrombotic treatment indication., Results: Of the 400 patients admitted for an ICH, 131 (33%) were treated by antithrombotic therapy: oral anti-vitamin K anticoagulants (VKA) in 14.1% of cases and antiplatelet agents in 15.1%. Of VKA patients, overdosage rate was 30.2%. The indication of antithrombotic therapy was debatable in 18.3% of cases., Conclusion: Our study highlights the frequency of ICH occurring on antithrombotic therapy and the significant proportion of "avoidable" ICH., (© 2013 Société Française de Pharmacologie et de Thérapeutique.)

Opinion Statement: Paraneoplastic disorders of the peripheral nervous system (PNS) are the most frequent manifestation of paraneoplasia. As with the central nervous system, two categories of immune mechanisms are distinguished. On one side, antibodies toward intracellular antigens (HuD and CV2-CRMP5) occur with subacute sensory neuronopathy or sensorimotor neuropathy probably depending on a T cell mediated disorder (group 1). On the other side, the Lambert-Eaton myasthenic syndrome (LEMS) and peripheral nerve hyperexcitability (PNH) occur with antibodies to cell membrane antigens, respectively, the voltage gated calcium channel and CASPR2 proteins, which are responsible for the disease (group 2). Treatment recommendation mostly depends on class IV studies. Three lines of therapeutics can be proposed, namely tumor, immunomodulatory and symptomatic treatments. Cancer treatment is crucial since an early tumor cure is the best way to stabilize patients in group 1 and improve those in group 2. This implies the use of an efficient strategy for cancer diagnosis. With group 2 symptomatic treatment including 3,4 diaminopyridine for LEMS and carbamazepine for PNH may suffice to obtain good quality remission. Immunomodulatory treatments like IVIg and plasma exchange, which have a well-established efficacy in antibody dependent diseases, may be used as second line treatments. Rituximab, for which there is only little evidence in this context, may be kept in a third line for severe refractory patients. With group 1 patients, who frequently develop an evolving and disabling disorder, bolus of methylprednisolone and or IVIg may be recommended while searching for and treating the tumor. If the tumor is not found and the patient deteriorates, monthly pulses of cyclophosphamide may stabilize the patients. Antidepressants and antiepileptic drugs efficacious in the treatment of neuropathic pain are to be used as symptomatic treatment when necessary. The choice is then based on the cost effectiveness and tolerance of these drugs.

An increase in S100 protein-positive cells has been reported in inflammatory bowel diseases, mainly Crohn disease. These cells were interpreted as myeloid-derived dendritic cells, chiefly in follicular areas. We were prompted to assess the nature of these cells in interfollicular areas of inflamed colonic mucosa in ulcerative colitis and study their involvement in tumor necrosis factor alpha production, the main inflammatory cytokine in ulcerative colitis. The number and distribution of cells expressing S100 protein, nerve growth factor receptor, CD68, CD1a, CD83, and calretinin were studied in samples from 16 patients with active ulcerative colitis using simple and double immunohistochemistry. Then, the localization in S100 protein-positive cells of (1) tumor necrosis factor alpha, (2) its sheddase A disintegrin and metalloprotease-17, and (3) the receptors TNFR1 was assessed using double immunofluorescence followed by confocal microscopy. In active ulcerative colitis, there was an increased number in S100 protein-positive cells in interfollicular areas of colonic mucosa compared with quiescent ulcerative colitis, nonulcerative colitis, or normal mucosa. All S100 protein-positive cells ensheathed calretinin-positive axons, indicating their Schwann cell origin. No CD1a- or CD83-positive dendritic cells were detected. Double immunofluorescence studies showed that in normal colon, Schwann cells of the mucosa and submucosal plexuses weakly expressed A disintegrin and metalloprotease-17 but did not express tumor necrosis factor alpha. By contrast, in active ulcerative colitis, they expressed both A disintegrin and metalloprotease-17 and tumor necrosis factor alpha. Schwann cells as well as calretinin-positive axons strongly expressed TNFR1. This study shows (1) a Schwann cell proliferation in the inflamed colonic mucosa during active ulcerative colitis and (2) that Schwann cells produce tumor necrosis factor alpha. Tumor necrosis factor alpha is thus likely to stimulate Schwann cell proliferation through an autocrine/paracrine mechanism.

The classic paraneoplastic neurological syndromes include Lambert-Eaton myasthenic syndrome, limbic encephalitis, sensory neuronopathy, intestinal pseudo-obstruction, subacute cerebellar degeneration, encephalomyelitis, and dermatomyositis. Approximately ten onconeural antibodies that recognize cancer and the nervous system have been described in paraneoplastic neurological syndromes. These antibodies appear to be important diagnostic tools, even though they may not always be present. Deciding whether a given neurological picture is definitely or possibly paraneoplastic depends on the clinical syndrome, any association with onconeural antibodies, and the time elapsed between onset of neurological symptoms and the discovery of the cancer. Diagnosis of a classic paraneoplastic neurological syndrome or the discovery of onconeural antibodies mandates an active and persistent search for cancer, using new techniques such as fluorodeoxyglucose positron emission tomography. In patients with one of these syndromes, the best treatment of the neurological disease is often the diagnosis and early treatment of the cancer.

Involvement of the peripheral nervous system (PNS) is common in patients with cancer and any part, including motor neurons, sensory ganglia, nerve roots, plexuses, cranial and peripheral nerves, and neuromuscular junctions, can be affected. Different mechanisms can initiate damage associated with cancer-related PNS disorders. These include tumour infiltration, toxicity of treatments, metabolic and nutritional perturbations, cachexia, virus infections, and paraneoplastic neurological syndromes. The type of cancer, lymphoma, or solid tumour is a further determinant of a PNS disorder. In this Review we discuss the different causes and mechanisms of disorders of the PNS in patients with cancer and we will focus on their assessment and diagnosis.

Objective: To study the utility of electroneuromyography in analysis of upper limb pain as a function of the existence of a diagnostic hypothesis., Methods: We retrospectively compared the consecutive electroneuromyographic examinations performed between 1 January and 30 September 2004. All recordings were performed by the same examiner in the neurophysiology clinic in the department of neurology of Saint-Etienne university hospital UHC at the request of hospital specialists or surgeon and private general practitioners. In each examination, at a minimum and regardless of the specific situation, motor conduction speed, F waves, and sensory conduction speed were recorded for the median nerve and the ulnar nerve on the right and left. For the arm in question, needle electromyography explored the muscles depending on the C5-T1 roots., Results: In all, 76 patients had ENMG examinations, 38 for whom the physician had a diagnostic hypothesis and 38 patients without. In the case of a diagnosis based on clinical suspicions, examination was normal in 73.7% of cases compared with 23.7% when there was a clinically based hypothesis (p<0.01). These findings did not vary significantly according to the specialization of the referring physician., Conclusion: Electromyography and nerve conduction studies are useful to confirm a diagnosis based on patient reports and clinical data, it is not useful when no diagnosis has been suggested.

Introduction: Sjögren-Larsson syndrome (SJS) is an autosomal-recessive disorder. Patients suffer from congenital ichtyosis, mental retardation and symmetric spastic paralysis. Ichtyosis is usually pronounced and associated with erythroderma. Neurological manifestations occur usually between 4 and 13 months of age. This genetic disease is due to fatty acid aldehyde dehydrogenase (FALDH) deficiency, leading to an accumulation of long-chain alcohols. The gene has been mapped to chromosome 17., Case Reports: A 52-year-old woman was hospitalized because of a severe erythroderma with ichtyosis. She suffered from epilepsy, spastic diplegia and mental retardation (Little disease has been diagnosed). The association of spastic paraparesia and ichtyosiform erythroderma suggested the diagnosis of SJS. This was confirmed by the very low level of FALDH activity. A 27-year-old patient was hospitalized for the recent onset paraparesia. Erythematous patches were observed on arm pits and buttocks. The diagnosis of SJS was not confirmed by FALDH assay., Discussion: Diagnosis of Sjögren-Larsson syndrome is a very rare disease in France. It is useful to evoke the diagnosis when spastic paraparesia is associated with these unusual cutaneous signs.