Settlement cue selectivity by larvae of the destructive crown-of-thorns starfish.

Population irruptions of crown-of-thorns starfish (COTS) cause extensive degradation of coral reefs, threatening the structure and function of these important ecosystems. For population irruptions to initiate and spread, large numbers of planktonic larvae have to successfully transition into their benthic life-history stage (i.e. settlement), whereby larval behaviour and the presence of settlement cues may shape spatial patterns of recruitment and adult densities. Our results demonstrate that a wide range of coralline algae species induce COTS larvae to settle; however, the capacity to promote settlement success varied manyfold among algal species, ranging from greater than 90% in Melyvonnea cf. madagascariensis to less than 2% in Lithophyllum cf. kotschyanum and two Porolithon species at 24 h. Because many coralline algae species that promote high settlement success are prevalent in shallow reef habitats, our findings challenge the hypothesis that COTS larvae predominantly settle in deep water. Considering both larval behaviour and algal ecology, this study highlights the ecological significance of coralline algae communities in driving recruitment patterns of COTS. More specifically, the local abundance of highly inductive coralline algae (especially, Melyvonnea cf. madagascariensis) may explain some of the marked spatial heterogeneity of COTS populations and the incidence of population irruptions.

Multimodal Biomarkers Quantify Recovery in Autoimmune Autonomic Ganglionopathy.

OBJECTIVE: The objective of this study was to evaluate patients with ganglionic acetylcholine receptor antibody (gAChR-Ab) positive autoimmune autonomic ganglionopathy using a multimodal testing protocol to characterize their full clinical phenotype and explore biomarkers to quantify immunotherapy response. METHODS: We conducted a cohort study of 13 individuals (7 women, 21-69 years of age) with autonomic failure and gAChR-Ab >100 pM identified between 2005 and 2019. From 2018, all patients were longitudinally assessed with cardiovascular, pupillary, urinary, sudomotor, lacrimal and salivary testing, and Composite Autonomic Symptom Score (COMPASS-31) autonomic symptom questionnaires. The orthostatic intolerance ratio was calculated by dividing change in systolic blood pressure over time tolerated on head-up tilt. Eleven patients received immunotherapy. RESULTS: At first assessment, all 13 patients had cardiovascular and pupillary impairments, 7 of 8 had postganglionic sudomotor dysfunction, 9 of 11 had urinary retention and xeropthalmia, and 6 of 8 had xerostomia. After immunotherapy, there were significant improvements in orthostatic intolerance ratio (33.3 [17.8-61.3] to 5.2 [1.4-8.2], p = 0.007), heart rate response to deep breathing (1.5 [0.0-3.3] to 4.5 [3.0-6.3], p = 0.02), pupillary constriction to light (12.0 [5.5-18.0] to 19.0 [10.6-23.8]%, p = 0.02), saliva production (0.01 [0.01-0.05] to 0.08 [0.02-0.20] g/min, p = 0.03), and COMPASS-31 scores (52 to 17, p = 0.03). Orthostatic intolerance ratio correlated with autonomic symptoms at baseline (r = 0.841, p = 0.01) and following immunotherapy (r = 0.889, p = 0.02). Immunofluorescence analyses of skin samples from a patient 32 years after disease onset showed loss of nerve fibers supplying the dermal autonomic adnexa and epidermis, with clear improvements following immunotherapy. INTERPRETATION: Patients with autoimmune autonomic ganglionopathy demonstrated objective evidence of widespread sympathetic and parasympathetic autonomic failure, with significant improvements after immunotherapy. Quantitative autonomic biomarkers should be used to define initial deficits, guide therapeutic decisions, and document treatment response. ANN NEUROL 2021;89:753-768.

Clinical features which predict neuronal surface autoantibodies in new-onset focal epilepsy: implications for immunotherapies.

OBJECTIVE: To generate a score which clinically identifies surface-directed autoantibodies in adults with new-onset focal epilepsy, and evaluate the value of immunotherapy in this clinical setting. METHODS: Prospective clinical and autoantibody evaluations in a cohort of 219 consecutive patients with new-onset focal epilepsy. RESULTS: 10.5% (23/219) of people with new-onset focal epilepsy had detectable serum autoantibodies to known or novel cell surface antigenic targets. 9/23 with autoantibodies were diagnosed with encephalitis, by contrast to 0/196 without autoantibodies (p<0.0001). Multivariate analysis identified six features which predicted autoantibody positivity (area under the curve=0.83): age ≥54 years, ictal piloerection, lowered self-reported mood, reduced attention, MRI limbic system changes and the absence of conventional epilepsy risk factors. 11/14 (79%) patients with detectable autoantibodies, but without encephalitis, showed excellent long-term outcomes (modified Rankin Score=0) despite no immunotherapy. These outcomes were superior to those of immunotherapy-treated patients with confirmed autoantibody-mediated encephalitis (p<0.05). CONCLUSIONS: Seizure semiology, cognitive and mood phenotypes, alongside inflammatory investigation findings, aid the identification of surface autoantibodies among unselected people with new-onset focal epilepsy. The excellent immunotherapy-independent outcomes of autoantibody-positive patients without encephalitis suggests immunotherapy administration should be guided by clinical features of encephalitis, rather than autoantibody positivity. Our findings suggest that, in this cohort, immunotherapy-responsive seizure syndromes with autoantibodies largely fall under the umbrella of autoimmune encephalitis.

NK Cell-mediated Neuroblastoma Cell Lysis is Enhanced by IgG From Patients With Pediatric Opsoclonus-Myoclonus Syndrome.

Pediatric opsoclonus-myoclonussyndrome (OMS) is a rare autoimmune disorder of which 50% are associated with neuroblastoma (NB). We investigated whether surface-binding autoantibodies in OMS can enhance natural killer (NK) cell-mediated cytotoxicity in these patients. OMS immunoglobulin G (IgG) bound to NB cell lines and NK cell-mediated cytotoxicity to NB cells was enhanced after preincubation with OMS-IgG, but not IgG from NB without OMS or healthy controls. Activation of NK cells by surface-binding autoantibodies may be an additional mechanism of antitumor immunity in children with NB and OMS.

Behaviour and neuropathology in mice injected with human contactin-associated protein 2 antibodies.

Serum antibodies that bind to the surface of neurons or glia are associated with a wide range of rare but treatable CNS diseases. In many, if not most instances, the serum levels are higher than CSF levels yet most of the reported attempts to reproduce the human disease in mice have used infusion of antibodies into the mouse cerebral ventricle(s) or intrathecal space. We used the intraperitoneal route and injected purified plasma IgG from either a CASPR2-antibody-positive patient (n = 10 mice) or healthy individual (n = 9 mice) daily for 8 days. Lipopolysaccharide was injected intraperitoneally on Day 3 to cause a temporary breach in the blood brain barrier. A wide range of baseline behaviours, including tests of locomotion, coordination, memory, anxiety and social interactions, were established before the injections and tested from Day 5 until Day 11. At termination, brain tissue was analysed for human IgG, CASPR2 and c-fos expression, lymphocyte infiltration, and neuronal, astrocytic and microglial markers. Mice exposed to CASPR2-IgG, compared with control-IgG injected mice, displayed reduced working memory during the continuous spontaneous alternation test with trends towards reduced short-term and long-term memories. In the open field tests, activities were not different from controls, but in the reciprocal social interaction test, CASPR2-IgG injected mice showed longer latency to start interacting, associated with more freezing behaviour and reduced non-social activities of rearing and grooming. At termination, neuropathology showed more IgG deposited in the brains of CASPR2-IgG injected mice, but a trend towards increased CASPR2 expression; these results were mirrored in short-term in vitro experiments where CASPR2-IgG binding to hippocampal neurons and to CASPR2-transfected HEK cells led to some internalization of the IgG, but with a trend towards higher surface CASPR2 expression. Despite these limited results, in the CASPR2-IgG injected mouse brains there was increased c-fos expression in the piriform-entorhinal cortex and hypothalamus, and a modest loss of Purkinje cells. There was also increased microglia density, morphological changes in both microglia and astrocytes and raised complement C3 expression on astrocytes, all consistent with glial activation. Patients with CASPR2 antibodies can present with a range of clinical features reflecting central, autonomic and peripheral dysfunction. Although the behavioural changes in mice were limited to social interactions and mild working-memory defects, the neuropathological features indicate potentially widespread effects of the antibodies on different brain regions.

Incidence and phenotypes of childhood-onset genetic epilepsies: a prospective population-based national cohort.

Epilepsy is common in early childhood. In this age group it is associated with high rates of therapy-resistance, and with cognitive, motor, and behavioural comorbidity. A large number of genes, with wide ranging functions, are implicated in its aetiology, especially in those with therapy-resistant seizures. Identifying the more common single-gene epilepsies will aid in targeting resources, the prioritization of diagnostic testing and development of precision therapy. Previous studies of genetic testing in epilepsy have not been prospective and population-based. Therefore, the population-incidence of common genetic epilepsies remains unknown. The objective of this study was to describe the incidence and phenotypic spectrum of the most common single-gene epilepsies in young children, and to calculate what proportion are amenable to precision therapy. This was a prospective national epidemiological cohort study. All children presenting with epilepsy before 36 months of age were eligible. Children presenting with recurrent prolonged (>10 min) febrile seizures; febrile or afebrile status epilepticus (>30 min); or with clusters of two or more febrile or afebrile seizures within a 24-h period were also eligible. Participants were recruited from all 20 regional paediatric departments and four tertiary children's hospitals in Scotland over a 3-year period. DNA samples were tested on a custom-designed 104-gene epilepsy panel. Detailed clinical information was systematically gathered at initial presentation and during follow-up. Clinical and genetic data were reviewed by a multidisciplinary team of clinicians and genetic scientists. The pathogenic significance of the genetic variants was assessed in accordance with the guidelines of UK Association of Clinical Genetic Science (ACGS). Of the 343 patients who met inclusion criteria, 333 completed genetic testing, and 80/333 (24%) had a diagnostic genetic finding. The overall estimated annual incidence of single-gene epilepsies in this well-defined population was 1 per 2120 live births (47.2/100 000; 95% confidence interval 36.9-57.5). PRRT2 was the most common single-gene epilepsy with an incidence of 1 per 9970 live births (10.0/100 000; 95% confidence interval 5.26-14.8) followed by SCN1A: 1 per 12 200 (8.26/100 000; 95% confidence interval 3.93-12.6); KCNQ2: 1 per 17 000 (5.89/100 000; 95% confidence interval 2.24-9.56) and SLC2A1: 1 per 24 300 (4.13/100 000; 95% confidence interval 1.07-7.19). Presentation before the age of 6 months, and presentation with afebrile focal seizures were significantly associated with genetic diagnosis. Single-gene disorders accounted for a quarter of the seizure disorders in this cohort. Genetic testing is recommended to identify children who may benefit from precision treatment and should be mainstream practice in early childhood onset epilepsy.

The importance of early immunotherapy in patients with faciobrachial dystonic seizures.

Faciobrachial dystonic seizures and limbic encephalitis closely associate with antibodies to leucine-rich glioma-inactivated 1 (LGI1). Here, we describe 103 consecutive patients with faciobrachial dystonic seizures and LGI1 antibodies to understand clinical, therapeutic and serological differences between those with and without cognitive impairment, and to determine whether cessation of faciobrachial dystonic seizures can prevent cognitive impairment. The 22/103 patients without cognitive impairment typically had normal brain MRI, EEGs and serum sodium levels (P < 0.0001). Overall, cessation of faciobrachial dystonic seizures with antiepileptic drugs alone occurred in only 9/89 (10%) patients. By contrast, 51% showed cessation of faciobrachial dystonic seizures 30 days after addition of immunotherapy (P < 0.0001), with earlier cessation in cognitively normal patients (P = 0.038). Indeed, expedited immunotherapy (P = 0.031) and normal cognition (P = 0.0014) also predicted reduced disability at 24 months. Furthermore, of 80 patients with faciobrachial dystonic seizures as their initial feature, 56% developed cognitive impairment after 90 days of active faciobrachial dystonic seizures. Whereas only one patient developed cognitive impairment after cessation of faciobrachial dystonic seizures (P < 0.0001). All patients had IgG4-LGI1 antibodies, but those with cognitive impairment had higher proportions of complement-fixing IgG1 antibodies (P = 0.03). Both subclasses caused LGI1-ADAM22 complex internalization, a potential non-inflammatory epileptogenic mechanism. In summary, faciobrachial dystonic seizures show striking time-sensitive responses to immunotherapy, and their cessation can prevent the development of cognitive impairment.awx323media15681705685001.

Brain-relevant antibodies in first-episode psychosis: a matched case-control study.

BACKGROUND: There has been much recent excitement about the possibility that some cases of psychosis may be wholly due to brain-reactive antibodies, with antibodies to N-methyl-D-aspartate receptor (NMDAR) and the voltage-gated potassium channel (VGKC)-complex reported in a few patients with first-episode psychosis (FEP). METHODS: Participants were recruited from psychiatric services in South London, UK, from 2009 to 2011 as part of the Genetics and Psychosis study. We conducted a case-control study to examine NMDAR and VGKC-complex antibody levels and rates of antibody positivity in 96 patients presenting with FEP and 98 controls matched for age and sex. Leucine-rich glioma inactiviated-1 (LGI1) and contactin-associated protein (CASPR) antibodies were also measured. Notably, patients with suspicion of organic disease were excluded. RESULTS: VGKC-complex antibodies were found in both cases (n = 3) and controls (n = 2). NMDAR antibody positivity was seen in one case and one control. Either LGI1-Abs or CASPR2-Abs were found in three cases and three controls. Neuronal antibody staining, consistent with the above results or indicating potential novel antigens, was overall positive in four patients but also in six controls. Overall, antibody positivity was at low levels only and not higher in cases than in controls. CONCLUSIONS: This case-control study of the prevalence of antibodies in FEP does not provide evidence to support the hypothesis that FEP is associated with an immune-mediated process in a subgroup of patients. Nevertheless, as other bio-clinical factors may influence the effect of such antibodies in a given individual, and patients with organic neurological disease may be misdiagnosed as FEP, the field requires more research to put these findings in context.

Hippocampal necrosis and sclerosis in cats: A retrospective study of 35 cases.

Hippocampal necrosis and hippocampal sclerosis in cats is a neuropathological entity which is a major concern in feline epilepsy. The aim of our study was to identify associated pathologic brain lesions possibly serving as aetiological triggers in this condition. Therefore, the formalin-fixed and paraffin waxembedded brain tissue of 35 cats diagnosed with hippocampal necrosis or sclerosis was examined retrospectively. In 26 cats inflammatory infiltrates could be found in the hippocampus or adjacent brain regions. Fifteen out of these animals demonstrated mild to moderate infiltrations by lymphocytes and complement deposition in the hippocampus similar to human limbic encephalitis, seven showed unspecific, predominantly non-suppurative inflammation, and two demonstrated suppurative inflammation of the hippocampus or adjacent brain regions. Additionally, one cat was diagnosed with central nervous manifestation of feline infectious peritonitis virus and another one with cerebral Toxoplasma gondii infection. Intracranial neoplasia was present in five cases altogether. Three of them comprised meningioma which was present additionally to lesions resembling limbic encephalitis in two cases, and a dentate gyrus alteration in one case. The other two tumour-associated cases comprised oligodendroglioma. Structural alterations of the dentate gyrus together with hippocampal sclerosis were encountered in three cases in total. Besides the case associated with a meningioma, one case demonstrated lesions resembling limbic encephalitis. A vascular infarct in the temporal lobe was encountered in one cat. In four cases no lesions other than hippocampal necrosis or sclerosis were found. The involvement of feline immunodeficiency virus infections, which may be able to produce hippocampal lesions, was not encountered in the cats examined.

Persistent microglial activation and synaptic loss with behavioral abnormalities in mouse offspring exposed to CASPR2-antibodies in utero.

Gestational transfer of maternal antibodies against fetal neuronal proteins may be relevant to some neurodevelopmental disorders, but until recently there were no proteins identified. We recently reported a fivefold increase in CASPR2-antibodies in mid-gestation sera from mothers of children with intellectual and motor disabilities. Here, we exposed mice in utero to purified IgG from patients with CASPR2-antibodies (CASPR2-IgGs) or from healthy controls (HC-IgGs). CASPR2-IgG but not HC-IgG bound to fetal brain parenchyma, from which CASPR2-antibodies could be eluted. CASPR2-IgG exposed neonates achieved milestones similarly to HC-IgG exposed controls but, when adult, the CASPR2-IgG exposed progeny showed marked social interaction deficits, abnormally located glutamatergic neurons in layers V-VI of the somatosensory cortex, a 16% increase in activated microglia, and a 15-52% decrease in glutamatergic synapses in layers of the prefrontal and somatosensory cortices. Thus, in utero exposure to CASPR2-antibodies led to permanent behavioral, cellular, and synaptic abnormalities. These findings support a pathogenic role for maternal antibodies in human neurodevelopmental conditions, and CASPR2 as a potential target.

Intracellular and non-neuronal targets of voltage-gated potassium channel complex antibodies.

OBJECTIVES: Autoantibodies against the extracellular domains of the voltage-gated potassium channel (VGKC) complex proteins, leucine-rich glioma-inactivated 1 (LGI1) and contactin-associated protein-2 (CASPR2), are found in patients with limbic encephalitis, faciobrachial dystonic seizures, Morvan's syndrome and neuromyotonia. However, in routine testing, VGKC complex antibodies without LGI1 or CASPR2 reactivities (double-negative) are more common than LGI1 or CASPR2 specificities. Therefore, the target(s) and clinical associations of double-negative antibodies need to be determined. METHODS: Sera (n=1131) from several clinically defined cohorts were tested for IgG radioimmunoprecipitation of radioiodinated α-dendrotoxin (125I-αDTX)-labelled VGKC complexes from mammalian brain extracts. Positive samples were systematically tested for live hippocampal neuron reactivity, IgG precipitation of 125I-αDTX and 125I-αDTX-labelled Kv1 subunits, and by cell-based assays which expressed Kv1 subunits, LGI1 and CASPR2. RESULTS: VGKC complex antibodies were found in 162 of 1131 (14%) sera. 90 of these (56%) had antibodies targeting the extracellular domains of LGI1 or CASPR2. Of the remaining 72 double-negative sera, 10 (14%) immunoprecipitated 125I-αDTX itself, and 27 (38%) bound to solubilised co-expressed Kv1.1/1.2/1.6 subunits and/or Kv1.2 subunits alone, at levels proportionate to VGKC complex antibody levels (r=0.57, p=0.0017). The sera with LGI1 and CASPR2 antibodies immunoprecipitated neither preparation. None of the 27 Kv1-precipitating samples bound live hippocampal neurons or Kv1 extracellular domains, but 16 (59%) bound to permeabilised Kv1-expressing human embryonic kidney 293T cells. These intracellular Kv1 antibodies mainly associated with non-immune disease aetiologies, poor longitudinal clinical-serological correlations and a limited immunotherapy response. CONCLUSIONS: Double-negative VGKC complex antibodies are often directed against cytosolic epitopes of Kv1 subunits and occasionally against non-mammalian αDTX. These antibodies should no longer be classified as neuronal-surface antibodies. They consequently lack pathogenic potential and do not in themselves support the use of immunotherapies.

Paraneoplastic cerebellar degeneration and lambert-eaton myasthenia in a patient with merkel cell carcinoma and voltage-gated calcium channel antibodies.

INTRODUCTION: Merkel cell carcinoma is a rare cutaneous, aggressive tumor. Although it shares many neuroendocrine features with small cell lung carcinoma, it has only occasionally been reported with paraneoplastic neurological syndromes. METHODS: A healthy 67-year-old man developed acute ataxia, vertigo, and nausea. Subsequently he also developed dysarthria, diplopia, xerostomia, fatigability and progressive anorexia. He underwent a full diagnostic workup and was found to have a high titer of voltage-gated calcium channel antibodies in serum and cerebrospinal fluid, neurophysiological findings compatible with Lambert-Eaton myasthenia and neurological signs compatible with cerebellar degeneration. RESULTS: A positron emission tomography study revealed a hypermetabolic lesion in the axilla, subsequently biopsied and consistent with Merkel cell carcinoma. CONCLUSIONS: In most previous reports, neurological symptoms preceded the Merkel cell carcinoma diagnosis, and the primary localization was in lymph nodes. This tumor should be considered in patients with paraneoplastic syndrome, and particularly Lambert-Eaton myasthenia after exclusion of small cell lung carcinoma. Muscle Nerve 56: 998-1000, 2017.

Neuronal antibodies in pediatric epilepsy: Clinical features and long-term outcomes of a historical cohort not treated with immunotherapy.

OBJECTIVE: In autoimmune encephalitis the etiologic role of neuronal cell-surface antibodies is clear; patients diagnosed and treated early have better outcomes. Neuronal antibodies have also been described in patients with pediatric epilepsy without encephalitis. The aim was to assess whether antibody presence had any effect on long-term outcomes in these patients. METHODS: Patients (n = 178) were recruited between 1988 and 1992 as part of the prospective Dutch Study of Epilepsy in Childhood; none received immunotherapy. Healthy age-matched bone-marrow donors served as controls (n = 112). All sera were tested for serum N-methyl-d-aspartate receptor (NMDAR), alpha amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor, leucine rich glioma inactivated 1, contactin associated protein like 2 (CASPR2), contactin-2, glutamic acid decarboxylase, and voltage gated potassium channel (VGKC)-complex antibodies by standard techniques. No cerebrospinal fluid (CSF) samples were available. Results were correlated with clinical data collected over 15 years. RESULTS: Seventeen patients (9.5%) were positive for VGKC complex (n = 3), NMDAR (n = 7), CASPR2 (n = 4), and contactin-2 (n = 3), compared to three (3/112; 2.6%) healthy controls (VGKC complex [n = 1], NMDAR [n = 2]; p = 0.03; Fisher's exact test). Titers were relatively low (≤1:100 for cell-surface antibodies), but 8 (47%) of the 17 positive samples bound to the surface of live hippocampal neurons consistent with a potential pathogenic antibody. Preexisting cognitive impairment was more frequent in antibody-positive patients (9/17 vs. 33/161; p = 0.01). Fourteen antibody-positive patients were treated with standard antiepileptic drugs (AEDs); three (17%) became intractable but this was not different from the 16 (10%) of 161 antibody-negative patients. In 96 patients with available follow-up samples at 6 and/or 12 months, 6 of 7 positive antibodies had disappeared and, conversely, antibodies had appeared for the first time in a further 7 patients. SIGNIFICANCE: Neuronal antibodies were found at low levels in 9.5% of patients with new-onset pediatric epilepsy but did not necessarily persist over time, and the development of antibodies de novo in later samples suggests they could be due to a secondary response to neuronal damage or inflammation. Moreover, as the response to standard AEDs and the long-term outcome did not differ from those of antibody-negative pediatric patients, these findings suggest that routine neuronal antibody testing is unlikely to be helpful in pediatric epilepsy. However, the higher incidence of preexisting cognitive problems in the antibody-positive group, the CASPR2 and contactin-2 antibodies in 7 of 17 patients, and the binding of 8 of 17 of serum samples to live hippocampal neurons suggest that neuronal antibodies, even if secondary, could contribute to the comorbidities of pediatric epilepsy.

Epileptogenic effects of NMDAR antibodies in a passive transfer mouse model.

Most patients with N-methyl D-aspartate-receptor antibody encephalitis develop seizures but the epileptogenicity of the antibodies has not been investigated in vivo. Wireless electroencephalogram transmitters were implanted into 23 C57BL/6 mice before left lateral ventricle injection of antibody-positive (test) or healthy (control) immunoglobulin G. Mice were challenged 48 h later with a subthreshold dose (40 mg/kg) of the chemo-convulsant pentylenetetrazol and events recorded over 1 h. Seizures were assessed by video observation of each animal and the electroencephalogram by an automated seizure detection programme. No spontaneous seizures were seen with the antibody injections. However, after the pro-convulsant, the test mice (n = 9) had increased numbers of observed convulsive seizures (P = 0.004), a higher total seizure score (P = 0.003), and a higher number of epileptic 'spike' events (P = 0.023) than the control mice (n = 6). At post-mortem, surprisingly, the total number of N-methyl D-aspartate receptors did not differ between test and control mice, but in test mice the levels of immunoglobulin G bound to the left hippocampus were higher (P < 0.0001) and the level of bound immunoglobulin G correlated with the seizure scores (R(2) = 0.8, P = 0.04, n = 5). Our findings demonstrate the epileptogenicity of N-methyl D-aspartate receptor antibodies in vivo, and suggest that binding of immunoglobulin G either reduced synaptic localization of N-methyl D-aspartate receptors, or had a direct effect on receptor function, which could be responsible for seizure susceptibility in this acute short-term model.

Paediatric brainstem encephalitis associated with glial and neuronal autoantibodies.

AIM: Central nervous system (CNS) autoantibodies have been reported in a range of neuroimmune diseases, but there has not been a systematic evaluation of autoantibodies in paediatric patients with brainstem encephalitis. METHOD: Serum samples from 57 children (40 male, 17 female, median age 12y, range 0.6-18y) with a diagnosis of brainstem encephalitis were tested retrospectively for antibodies to GQ1b, aquaporin-4 (AQP4), myelin oligodendrocyte glycoprotein (MOG), N-methyl-D-aspartate receptor, LGI1, CASPR2, glycine receptor (GlyR), DPPX, and the voltage gated potassium channel (VGKC)-complex. RESULTS: Disease localized to the brainstem was seen in 19 patients: Bickerstaff's brainstem encephalitis (n=14) and clinically isolated syndrome (n=5). Polyfocal presentation was seen in 38 children, with predominantly white matter disease in 18 patients and grey matter in 20 patients. CNS surface antibodies were found in 22/57 patients (two patients with double positivity): GQIb (n=6), NMDAR (n=7), GlyR (n=5), MOG (n=5), and one AQP4. Three patients were positive for VGKC-complex antibodies. All patients were negative for antibodies to DPPX and the VGKC-complex antigens LGI1, CASPR2, and contactin-2. Although there were some partial differences in the presentations, the clinical features and outcomes did not relate clearly to the presence or absence of specific antibodies. INTERPRETATION: As determined retrospectively, 39% of patients had cell surface antibodies. The results did not suggest any relationship with treatment or outcomes obtained but it is possible that specific antibody detection could be a helpful guide to more intensive immunotherapies in some cases.

Glycine receptor antibodies in PERM and related syndromes: characteristics, clinical features and outcomes.

The clinical associations of glycine receptor antibodies have not yet been described fully. We identified prospectively 52 antibody-positive patients and collated their clinical features, investigations and immunotherapy responses. Serum glycine receptor antibody endpoint titres ranged from 1:20 to 1:60 000. In 11 paired samples, serum levels were higher than (n = 10) or equal to (n = 1) cerebrospinal fluid levels; there was intrathecal synthesis of glycine receptor antibodies in each of the six pairs available for detailed study. Four patients also had high glutamic acid decarboxylase antibodies (>1000 U/ml), and one had high voltage-gated potassium channel-complex antibody (2442 pM). Seven patients with very low titres (<1:50) and unknown or alternative diagnoses were excluded from further study. Three of the remaining 45 patients had newly-identified thymomas and one had a lymphoma. Thirty-three patients were classified as progressive encephalomyelitis with rigidity and myoclonus, and two as stiff person syndrome; five had a limbic encephalitis or epileptic encephalopathy, two had brainstem features mainly, two had demyelinating optic neuropathies and one had an unclear diagnosis. Four patients (9%) died during the acute disease, but most showed marked improvement with immunotherapies. At most recent follow-up, (2-7 years, median 3 years, since first antibody detection), the median modified Rankin scale scores (excluding the four deaths) decreased from 5 at maximal severity to 1 (P < 0.0001), but relapses have occurred in five patients and a proportion are on reducing steroids or other maintenance immunotherapies as well as symptomatic treatments. The glycine receptor antibodies activated complement on glycine receptor-transfected human embryonic kidney cells at room temperature, and caused internalization and lysosomal degradation of the glycine receptors at 37°C. Immunoglobulin G antibodies bound to rodent spinal cord and brainstem co-localizing with monoclonal antibodies to glycine receptor-α1. Ten glycine receptor antibody positive samples were also identified in a retrospective cohort of 56 patients with stiff person syndrome and related syndromes. Glycine receptor antibodies are strongly associated with spinal and brainstem disorders, and the majority of patients have progressive encephalomyelitis with rigidity and myoclonus. The antibodies demonstrate in vitro evidence of pathogenicity and the patients respond well to immunotherapies, contrasting with earlier studies of this syndrome, which indicated a poor prognosis. The presence of glycine receptor antibodies should help to identify a disease that responds to immunotherapies, but these treatments may need to be sustained, relapses can occur and maintenance immunosuppression may be required.

Epilepsy and autoimmunity in pediatric patients.

Our aim was to determine the presence and possible role of autoantibodies in epileptic patients with an undetermined etiology. Eighty epilepsy patients, who were referred to the Pediatric Neurology Department at Ankara University between November 2011 and April 2012, were enrolled in the study. Antinuclear antibodies (ANA), anticardiolipin IgG, antiphospholipid, antithyroid peroxidase, paraneoplastic, glutamic acid decarboxylase (GAD), and N-methyl-d-aspartate (NMDA) receptor antibodies were studied in our university laboratory. In addition, NMDA receptor (NMDAR), voltage-gated potassium channel (VGKC)-complex, leucine-rich, glioma inactivated 1 (LGI1) and contactin-associated protein 2 (CASPR2) antibodies were studied at the Oxford University Immunology Laboratory. The study included 35 girls (44%) and 45 boys (56%) with a mean symptom age of 8.6 ± 4.53 years. ANA was detected in 15 (18.8%), antiphospholipid Ab in 3 (3.75%), anticardiolipin Ab in 1 (1.25%), and antithyroid peroxidase in 3 (3.75%) epileptic patients. In addition, anti-GAD Ab was detected in 7 (8.75%), anti-Yo Ab in 3 (3.75%), and anti-Ma2 in 3 (3.75%) epileptic patients. Anti-VGKC was positive in 13 (16.25%) epileptic patients. We performed a pioneer study to investigate the association between autoimmunity and pediatric epilepsy and we conclude that autoimmunity should be considered in epileptic patients with an undetermined etiology.

Investigation of neuronal autoantibodies in two different focal epilepsy syndromes.

OBJECTIVE: Neuronal antibodies have been identified in patients with seizures as the main or sole symptom. Our aim was to investigate the prevalence of these autoantibodies in patients with focal epilepsy of unknown cause (FEoUC) and in the group having mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS). METHODS: We studied anti-neuronal antibodies of consecutive adult patients diagnosed with FEoUC and MTLE-HS in our epilepsy center. The clinical and laboratory features of antibody-positive patients were compared with those of seronegative patients. The responses to therapy have also been investigated. RESULTS: Sera from 81 patients with epilepsy were tested. We found antibodies against glycine receptor (GLY-R) in 5 (6.2%), contactin-associated protein 2 (CASPR-2) in 4 (4.9%), N-methyl-d-aspartate receptor (NMDA-R) in 2 (2.5%), and voltage-gated potassium channel (VGKC)-complex in 2 (2.5%) of our patients with epilepsy. Psychotic attacks and nonspecific magnetic resonance imaging (MRI) white matter changes (WMCs) showed significant associations in seropositive patients (p = 0.003 and p = 0.03, respectively). Poor drug-response rates and total seizure counts were also higher in the seropositive patients but without reaching statistical significance. Three seropositive patients with previous epilepsy surgery showed typical histopathologic results for MTLE-HS, but not inflammatory changes. Moreover, some patients harboring these antibodies partly benefited from immunotherapy. SIGNIFICANCE: We detected neuronal antibodies in one sixth of patients with focal epilepsy, GLY-R antibodies being the leading one. Psychosis or nonspecific MRI WMCs were frequent in the seropositive group. Our results suggested that relevant antibodies should be screened for a treatment possibility in these groups.

Faciobrachial dystonic seizures: the influence of immunotherapy on seizure control and prevention of cognitive impairment in a broadening phenotype.

Voltage-gated potassium channel complex antibodies, particularly those directed against leucine-rich glioma inactivated 1, are associated with a common form of limbic encephalitis that presents with cognitive impairment and seizures. Faciobrachial dystonic seizures have recently been reported as immunotherapy-responsive, brief, frequent events that often predate the cognitive impairment associated with this limbic encephalitis. However, these observations were made from a retrospective study without serial cognitive assessments. Here, we undertook the first prospective study of faciobrachial dystonic seizures with serial assessments of seizure frequencies, cognition and antibodies in 10 cases identified over 20 months. We hypothesized that (i) faciobrachial dystonic seizures would show a differential response to anti-epileptic drugs and immunotherapy; and that (ii) effective treatment of faciobrachial dystonic seizures would accelerate recovery and prevent the development of cognitive impairment. The 10 cases expand both the known age at onset (28 to 92 years, median 68) and clinical features, with events of longer duration, simultaneously bilateral events, prominent automatisms, sensory aura, and post-ictal fear and speech arrest. Ictal epileptiform electroencephalographic changes were present in three cases. All 10 cases were positive for voltage-gated potassium channel-complex antibodies (346-4515 pM): nine showed specificity for leucine-rich glioma inactivated 1. Seven cases had normal clinical magnetic resonance imaging, and the cerebrospinal fluid examination was unremarkable in all seven tested. Faciobrachial dystonic seizures were controlled more effectively with immunotherapy than anti-epileptic drugs (P = 0.006). Strikingly, in the nine cases who remained anti-epileptic drug refractory for a median of 30 days (range 11-200), the addition of corticosteroids was associated with cessation of faciobrachial dystonic seizures within 1 week in three and within 2 months in six cases. Voltage-gated potassium channel-complex antibodies persisted in the four cases with relapses of faciobrachial dystonic seizures during corticosteroid withdrawal. Time to recovery of baseline function was positively correlated with time to immunotherapy (r = 0.74; P = 0.03) but not time to anti-epileptic drug administration (r = 0.55; P = 0.10). Of 10 cases, the eight cases who received anti-epileptic drugs (n = 3) or no treatment (n = 5) all developed cognitive impairment. By contrast, the two who did not develop cognitive impairment received immunotherapy to treat their faciobrachial dystonic seizures (P = 0.02). In eight cases without clinical magnetic resonance imaging evidence of hippocampal signal change, cross-sectional volumetric magnetic resonance imaging post-recovery, after accounting for age and head size, revealed cases (n = 8) had smaller brain volumes than healthy controls (n = 13) (P < 0.001). In conclusion, faciobrachial dystonic seizures can be prospectively identified as a form of epilepsy with an expanding phenotype. Immunotherapy is associated with excellent control of the frequently anti-epileptic drug refractory seizures, hastens time to recovery, and may prevent the subsequent development of cognitive impairment observed in this study.