Antineuronal Antibodies Research Articles

Serum and Cerebrospinal Fluid Testing in Optic Neuropathy Patients with Malignant Tumors.

Purpose To evaluate the value of serum and cerebrospinal fluid (CSF) testing in optic neuropathy (ON) patients with malignant tumors. Methods Fourteen patients clinically diagnosed as ON with malignant tumors but without intracranial or orbital mass in MRI were included in this study. Detailed medical records including medical history, complete ophthalmic examination, colour fundus photography, visual field test, orbital MRI examination, serum and CSF testing data were collected and analyzed. The diagnosis of paraneoplastic optic neuropathy (PON) based on the 2004 recommended criteria of the paraneoplastic syndrome- Euronetwork consortium for paraneoplastic neurological disorders, and current adaption for neuropathies. All patients underwent serum tests for pathogens and autoantibodies including antinuclear antibodies, anticardiolipin antibodies, antineutrophil cytoplasmic antibodies, AQP4-Ab and MOG-Ab, as well as CSF tests for malignant cells under microscope. Serum paraneoplastic antibodies were detected in PON patients. Monkey cerebellar tissue-based assay was used to detect unknown serum anti-neuron antibodies in PON patients with negative paraneoplastic antibody testing results. Results Fourteen ON patients were classified as four groups based on their clinical and MRI characteristics, as well as serum and CSF testing results: [1] definite PON, 6 cases (11 eyes); [2] possible PON, 3 case (5 eyes); [3] meningeal carcinomatosis-associated optic neuropathy (MCON), 4 cases (6 eyes); [4] infiltrative optic neuropathy (ION), 2 cases (2 eyes). Malignant cells were found under microscope in CSF samples from MCON and ION patients, contrast to no malignant cells in CSF samples from PON cases. All 14 ON patients with malignant tumors showed negative results in serum tests for pathogens and autoantibodies. Serum paraneoplastic antibodies were tested in PON patients, anti- CV2, anti-Yo, and anti- amphiphysin were detected positive in 2, 1, and 1 case, respectively, in definite PON group, whereas no serum paraneoplastic antibody detected in possible PON group. Two unknown serum antineuronal antibodies (an anti- Purkinje cell antibody and an anti-granular cell antibody) were detected using monkey cerebellar tissue-based assay in 2 of 5 PON patients with negative paraneoplastic antibody test results. Conclusions Serum and CSF tests are of great importance in differentiating different subtypes of ON with malignant tumors. Current diagnosis of PON still depends on combination of clinical and MRI manifestations, as well as serum and CSF tests. Tissue-based assay may help to detect new biomarkers for ON etiology and diagnosis.

Research progress of anti-γ-aminobutyric acid B receptor encephalitis and a case report of paraneoplastic associated encephalitis and treatment analysis.

Encephalitis is one of the common diseases in neurology. Early diagnosis and appropriate treatments are essential. Autoimmune encephalitis (AE) generally refers to a type of encephalitis mediated by autoimmune mechanisms. It is gradually considered to be an important cause of reversible encephalitis caused by noninfectious factors. It can occur in children, adolescents, and adults, and is clinically characterized by multifocal or diffuse brain damage such as personality changes, seizures, and cognitive impairment, with an overall good effect of immunotherapy. According to the clinical features of the patients, blood and cerebrospinal fluid tests, neuroelectrophysiology, cranial imaging, treatment and prognosis, AEs can be broadly divided into specific antigen (antibody)-related AEs and nonspecific antigen (or antibody) -related AEs. With the development of AEs research, more and more anti-neuron antibodies have been found, which provides an important reference for the diagnosis and treatment of AEs. Understanding the knowledge about AEs is important to discover new diseases and deepen the understanding of the immunopathological mechanisms of existing central nervous system diseases. Anti-γ-aminobutyric acid B (GABA-B) receptor encephalitis is a type of AE, but this disease is rare in AE, often develop to the clinical manifestations of marginal encephalitis, accompanied by obvious seizures or status epilepticus, Some patients had tumors, mainly small-cell carcinoma, prompt diagnosis, early immunotherapy and, if necessary, tumor treatment resulted in complete or partial neurological improvement in most patients.

Fixed myelin oligodendrocyte glycoprotein (MOG) autoantibody cell-based assays (CBA): A cautionary tale

Differentiating myelin oligodendrocyte glycoprotein antibody (MOGAb) associated disease (MOGAD) from multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) has prognostic and treatment implications. Use of surface expressing CBAs to detect clinically relevant MOG-IgG improves the analytical and clinical specificity when compared to ELISA or immunoblot. In addition, this test is useful for ruling out MS at the first demyelinating event in children.1 Commercial multiplex, fixed CBAs provide a convenient means of simultaneously testing for multiple anti-neuronal antibodies.

Paraneoplastic and Other Autoimmune Encephalitides: Antineuronal Antibodies, T Lymphocytes, and Questions of Pathogenesis.

Autoimmune and paraneoplastic encephalitides represent an increasingly recognized cause of devastating human illness as well as an emerging area of neurological injury associated with immune checkpoint inhibitors. Two groups of antibodies have been detected in affected patients. Antibodies in the first group are directed against neuronal cell surface membrane proteins and are exemplified by antibodies directed against the N-methyl-D-aspartate receptor (anti-NMDAR), found in patients with autoimmune encephalitis, and antibodies directed against the leucine-rich glioma-inactivated 1 protein (anti-LGI1), associated with faciobrachial dystonic seizures and limbic encephalitis. Antibodies in this group produce non-lethal neuronal dysfunction, and their associated conditions often respond to treatment. Antibodies in the second group, as exemplified by anti-Yo antibody, found in patients with rapidly progressive cerebellar syndrome, and anti-Hu antibody, associated with encephalomyelitis, react with intracellular neuronal antigens. These antibodies are characteristically found in patients with underlying malignancy, and neurological impairment is the result of neuronal death. Within the last few years, major advances have been made in understanding the pathogenesis of neurological disorders associated with antibodies against neuronal cell surface antigens. In contrast, the events that lead to neuronal death in conditions associated with antibodies directed against intracellular antigens, such as anti-Yo and anti-Hu, remain poorly understood, and the respective roles of antibodies and T lymphocytes in causing neuronal injury have not been defined in an animal model. In this review, we discuss current knowledge of these two groups of antibodies in terms of their discovery, how they arise, the interaction of both types of antibodies with their molecular targets, and the attempts that have been made to reproduce human neuronal injury in tissue culture models and experimental animals. We then discuss the emerging area of autoimmune neuronal injury associated with immune checkpoint inhibitors and the implications of current research for the treatment of affected patients.

Movement disorders associated with neuronal antibodies: a data-driven approach.

BackgroundMovement disorders can be associated with anti-neuronal antibodies.MethodsWe conducted a systematic review of cases with documented anti-neuronal antibodies in serum and/or cerebrospinal fluid published in PubMed before April 1, 2020. Only patients with at least one movement disorder were included. We used random forests for variable selection and recursive partitioning and regression trees for the creation of a data-driven decision algorithm, integrated with expert’s clinical feedback. ResultsThree hundred and seventy-seven studies met eligibility criteria, totaling 844 patients and 13 antibodies: amphiphysin, GAD, GlyR, mGluR1, ANNA-2/Ri, Yo/PCA-1, Caspr2, NMDAR, LGI-1, CRMP5/CV2, ANNA-1/Hu, IgLON5, and DPPX. Stiffness/rigidity/spasm spectrum symptoms were more frequently associated with amphiphysin, GAD, and GlyR; ataxia with mGluR1, ANNA-2/Ri, Yo/PCA-1, Caspr2, and ANNA-1/Hu; dyskinesia with NMDAR and paroxysmal movement with LGI1; chorea/choreoathetosis with CRMP5/CV2, IgLON5, and NMDAR; myoclonus with GlyR and DPPX; tremors with ANNA2/Ri and anti-DPPX; and parkinsonism with IgLON5 and NMDAR. Data-driven classification analysis determined the following diagnostic predictions (with probability selection): psychiatric symptoms and dyskinesia predicted NMDAR (71% and 87%, respectively); stiffness/rigidity/spasm and ataxia, GAD (67% and 47%, respectively); ataxia and opsoclonus, ANNA-2/Ri (68%); chorea/choreoathetosis, CRMP5/CV2 (41%). These symptoms remained the top predictors in random forests analysis. The integration with an expert opinion analysis refined the precision of the approach. Breast and lung tumors were the most common tumors. On neuroimaging, cerebellar involvement was associated with GAD and Yo/PCA-1; temporal involvement with Caspr2, LGI-1, ANNA-1/Hu. ConclusionSelected movement disorders are associated with specific anti-neuronal antibodies. The combination of data-driven and expert opinion approach to the diagnosis may assist early management efforts. Supplementary InformationThe online version contains supplementary material available at 10.1007/s00415-021-10934-7.

Contribution of the Enteric Nervous System to Autoimmune Diseases and Irritable Bowel Syndrome.

Anti-neuronal autoantibodies can lead to subacute gastrointestinal dysmotility, presenting with various symptoms typical of intestinal pseudoobstruction, achalasia, gastroparesis, or slow intestinal transit, among others. Such autoantibodies may be produced in response to a remote tumor and accelerate the diagnosis of malignancy, but in other cases they appear without an identifiable underlying cause. One example is the type I anti-neuronal nuclear antibody (ANNA-1 otherwise known as anti-Hu), which is usually linked to small cell-lung carcinoma. Anti-Hu can directly activate enteric neurons and visceral sensory nerve fibers and has a cytotoxic effect. Various other anti-neuronal antibodies have been described, targeting different ion channels or receptors on nerve cells of the central or the enteric nervous system. Autoimmune processes targeting enteric neurons may also play a role in more common disorders such as esophageal achalasia, celiac disease, or multiple sclerosis. Furthermore, anti-enteric neuronal antibodies have been found more abundant in the common functional gastrointestinal disorder, irritable bowel syndrome (IBS), than in controls. The pathogenesis of IBS is very complex, involving the release of various mediators from immune cells in the gut wall. Products of mast cells, such as histamine and tryptase, excite visceral afferents and enteric neurons, which may contribute to symptoms like abdominal pain and disturbed motility. Elevated serine- and cysteine-protease activity in stool of IBS-D and IBS-C patients, respectively, can be a factor leading to leaky gut and visceral hypersensitivity. More knowledge on these mediators in IBS may facilitate the development of novel diagnostic methods or therapies.

Permanent impairment of language in an adolescent case of autoimmune encephalitis

In pediatric and adolescent population, autoimmune encephalitis (AE) may present with a wide variety of symptoms including cognitive regression accompanied with loss of language skills. Despite its high prevalence in AE, linguistic functions have not been investigated in extensive detail. A 12-year-old girl with no significant premorbid history and normal school performance presented with fever, hypersomnia, nocturnal myoclonus and behavioral changes. Although neurological examination was normal, psychiatric evaluation revealed euphoria, mild irritability and visual hallucinations. Cranial MRI was normal, whereas cerebrospinal fluid (CSF) analysis showed elevated protein concentration and lymphocyte count, electroencephalogram (EEG) showed diffuse slow waves. A panel for anti-neuronal antibodies demonstrated glutamic acid decarboxylase (GAD) antibodies in the serum. Following immunotherapy, all neurological and behavioral symptoms vanished. However, the patient suffered from significant worsening of school performance. Psychiatric evaluation revealed severe depression. Assessment of intelligence done on the 10th and 18th month of follow-up yielded significantly low scores at mental retardation level. Linguistic assessment showed significant impairment in all domains but especially in semantics. Our case emphasizes the fact that AE may cause permanent cognitive dysfunction and language impairment even in patients with normal MRI/neurological examination findings and relatively mild treatment-responsive disease course.

Movement Disorders in Oncology: From Clinical Features to Biomarkers.

Background: the study of movement disorders associated with oncological diseases and anticancer treatments highlights the wide range of differential diagnoses that need to be considered. In this context, the role of immune-mediated conditions is increasingly recognized and relevant, as they represent treatable disorders. Methods: we reappraise the phenomenology, pathophysiology, diagnostic testing, and treatment of movement disorders observed in the context of brain tumors, paraneoplastic conditions, and cancer immunotherapy, such as immune-checkpoint inhibitors (ICIs). Results: movement disorders secondary to brain tumors are rare and may manifest with both hyper-/hypokinetic conditions. Paraneoplastic movement disorders are caused by antineuronal antibodies targeting intracellular or neuronal surface antigens, with variable prognosis and response to treatment. ICIs promote antitumor response by the inhibition of the immune checkpoints. They are effective treatments for several malignancies, but they may cause movement disorders through an unchecked immune response. Conclusions: movement disorders due to focal neoplastic brain lesions are rare but should not be missed. Paraneoplastic movement disorders are even rarer, and their clinical-laboratory findings require focused expertise. In addition to their desired effects in cancer treatment, ICIs can induce specific neurological adverse events, sometimes manifesting with movement disorders, which often require a case-by-case, multidisciplinary, approach.

Anti-neuron antibody syndrome: clinical features, cytokines/chemokines and predictors

BackgroundNeuroimmunology is a rapidly expanding field, and there have been recent discoveries of new antibodies and neurological syndromes. Most of the current clinical studies have focused on disorders involving one specific antibody. We have summarized a class of antibodies that target common neuronal epitopes, and we have proposed the term “anti-neuron antibody syndrome” (ANAS). In this study, we aimed to clarify the clinical range and analyse the clinical features, cytokines/chemokines and predictors in ANAS.MethodsThis was a retrospective cohort study investigating patients with neurological manifestations that were positive for anti-neuron antibodies.ResultsA total of 110 patients were identified, of which 43 patients were classified as having autoimmune encephalitis (AE) and the other 67 were classified as having paraneoplastic neurological syndrome (PNS). With regards to anti-neuron antibodies, 42 patients tested positive for anti-N-methyl-D-aspartate receptor (NMDAR) antibody, 19 for anti-Hu, 14 for anti-Yo and 12 for anti-PNMA2 (Ma2). There were significant differences between the ANAS and control groups in serum B cell-activating factor (BAFF) levels and in cerebrospinal fluid (CSF) C-X-C motif chemokine10 (CXCL10), CXCL13, interleukin10 (IL10), BAFF and transforming growth factor β1 (TGFβ1) levels. Predictors of poor outcomes included having tumours (P = 0.0193) and having a chronic onset (P = 0.0306), and predictors of relapses included having lower levels of CSF BAFF (P = 0.0491) and having a larger ratio of serum TGFβ1/serum CXCL13 (P = 0.0182).ConclusionsMost patients with ANAS had a relatively good prognosis. Having tumours and a chronic onset were both associated with poor outcomes. CSF BAFF and the ratio of serum TGFβ1/serum CXCL13 were associated with relapses.

Seizures in autoimmune encephalitis: specific features based on a systematic comparative study.

To highlight specific characteristics of seizure semiology and EEG features associated with different subtypes of autoimmune encephalitis (AE). We systematically reviewed the seizure semiology and all the EEG recordings from patients with AE managed in a tertiary referral centre for epilepsy and a neuro-intensive care unit. Each characteristic across the different subtypes of AE was compared by post hoc analysis. We identified 66 patients with anti-neuronal antibody-mediated AE or Rasmussen's encephalitis (RE) experiencing seizures, which were the most frequent symptom at onset. Anti-NMDAR and anti-LGI1 AE accounted for the majority of patients; 41% and 24%, respectively. We isolated specific semiological features, such as early tonic-clonic seizures (TCS) in anti-NMDAR AE, early mesial temporal lobe seizures with emotional symptoms in anti-GAD AE, somatosensory seizures in RE, and a lower frequency of TCS in anti-LGI1 AE. EEG analysis also provided additional insights into distinguishing the subtypes based on: (1) generalized rhythmic delta activity, which was more sensitive than extreme delta brush in identifying anti-NMDAR AE among all subtypes; and (2) temporal interictal epileptiform activity and temporal seizures on EEG in anti-GAD AE. We identified a new EEG pattern consisting of temporal low-voltage and periodic spikes associated with ipsilateral hippocampal abnormalities on MRI, which could be a sign of inflammatory mesial temporal involvement. Specific clinical and EEG features can be useful in guiding the diagnosis of a subtype of AE with acute symptomatic seizures, particularly before the results of anti-neuronal antibody testing are available.

Immune-mediated neurological syndrome in SARS-CoV-2 infection: a review of literature on autoimmune encephalitis in COVID-19.

IntroductionThe novel Coronavirus Disease 2019 (COVID-19) is an infection caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) which has been spreading rapidly amongst humans and causing a global pandemic. The notorious infection has shown to cause a wide spectrum of neurological syndrome, including autoimmune encephalitis.ObjectiveHere, we systematically review the literature on autoimmune encephalitis that developed in the background of SARS-CoV-2 infections and also the possible pathophysiological mechanisms of auto-immune mediated damage to the nervous system.MethodologyAn exhaustive search was made in Medline/PubMed, Embase, Scopus and other medical databases, and 28 relevant published articles were selected according to the strict inclusion criteria.ResultsAutoimmune encephalitis can occur via three possible proposed pathophysiological mechanism and can manifest during or after the acute infection period. It is more common in adult but can also occur in the paediatric patients. There were various spectra of autoantibody panels reported including antineuronal antibody, anti-gangliosides antibody and onconeural antibody. Majority of the patients responded well to the immunomodulating therapy and achieved good recovery.ConclusionIn conclusion, SARSCoV-2 infection can induce various spectrum of autoimmune encephalitis. It is a major concern since there is very limited long-term study on the topic. Hence, this review aims to elucidate on the potential long-term complication of SARS-CoV-2 infection and hopefully to improve the management and prognosis of COVID-19.

Evaluation of antineuronal antibodies and 8-OHdG in mothers of children with autism spectrum disorder: a case-control study

Objective The purpose of our study was to investigated the anti-Yo, anti-Hu, anti-Ri, anti-amphiphysin antibody levels and 8-OHdG in mothers of children with autism. Methods This study included 60 participants, 33 of whom were healthy mothers of 3–12-year-old children diagnosed with autism spectrum disorder (ASD) and the 27 others who constituted the control group, were healthy mothers with age-matched healthy children. Two groups were examined for plasma anti-Yo, anti-Hu, anti-amphiphysin and anti-Ri antibodies and, 8-OHdG levels. The participants were asked to accomplish a sociodemographic data form. The severity of ASD symptoms was evaluated according to the Childhood Autism Rating Scale (CARS). Results Anti-amphiphysin antibody levels and anti-Ri antibody positivity were significantly higher in the case group (p = 0.001; p = 0.027, respectively). The two groups did not significantly differ in terms of anti-Yo and anti-Hu antibody levels and in terms of 8-OHdG levels (p = 0.065; p = 0.099; p = 0.490, respectively). The two groups did not significantly differ in terms of sociodemographic data (p > 0.05). Conclusions According to the our study, maternal antineuronal antibodies, such as anti-amphiphysin and anti-Ri, may contribute to the risk of childhood autism. Studies with larger samples are needed. KEY POINTS Maternal factors associated with autism should be investigated in order to create early diagnosis and treatment opportunities for autism. Based on the importance of immunological and cerebellar pathologies in autism aetiology, we aimed to investigate antineuronal antibodies in mothers of children with autism. Maternal antineuronal antibodies, such as anti-amphiphysin and anti-Ri, may contribute to the risk of childhood autism. High anti-amphiphysin antibody levels in mothers of children with autism may also occur against the amphiphysin in the structure of the SrGAP3 gene, which is associated with autism.

Abdominal Segmental Myoclonus Mimicking Belly Dancer Dyskinesias in CASPR2 Antibody Encephalomyelitis.

An 86-year-old man presented with continuous movements of the abdominal wall (abdominal segmental myoclonus mimicking a belly dancer), gait unsteadiness, progressive cognitive deficit, episodic symptomatic hypotension, and diaphoresis for 2 months. Clinical examination confirmed cognitive dysfunction, and showed bilateral proximal muscle weakness of the upper and lower limbs and absent deep tendon reflexes. The Video shows the presence of spontaneous rhythmic, continuous, sinuous movements involving the abdominal muscles (Video 1). MRI of the spinal cord and the brain were normal. Electroencephalography showed generalized background slowing in the absence of epileptiform discharges. Polymyographic studies revealed rhythmic (about 2 Hz) electromyography bursts with variable duration of 500 to 1000 ms present with synchronous onset in the rectus abdominis and paravertebral muscles (Fig. 1). Detailed blood analysis was normal except for the presence of contactin-associated protein-like 2 (CASPR2) antibodies (IgG ≥1:40960). Cerebrospinal fluid analyses showed the presence of oligoclonal bands and CASPR2 antibody (IgG ≥1:160). Other anti-neuronal antibodies were absent, both on blood and cerebrospinal fluid analyses. Thoraco-abdominal-pelvic CT and whole-body FDG-PET did not show thymoma or other neoplasia. A diagnosis of CASPR2 antibody-related encephalomyelitis was made. Treatment with intravenous immunoglobulin and oral corticosteroids was started. Because of the absence of clinical improvement, plasma exchange and rituximab treatment were started leading to dramatic improvement of abdominal myoclonus but moderate effect on gait unsteadiness and cognitive deficit. CASPR2 is a membrane protein expressed in the central and peripheral nervous system, with its cytoplasmic domain essential for the function of potassium channel Kv1.1 clustering at the juxtaparanodes of myelinated axons. It is involved in neuronal excitability (i.e., stabilize conduction at nodes of Ranvier, and maintain resting potential) and synaptic transmission.1 CASPR2 antibodies induce a functional blocking of the potassium channel. CASPR2 antibody–associated disorders include acquired neuromyotonia, Morvan syndrome, limbic encephalitis, seizures and cerebellar ataxia. Diagnosis of CASPR2-related nervous system disorders is based on the clinical presentation and the presence of specific autoantibodies. Based on the earlier reported cases of CASPR2-associated encephalomyelitis, cerebral and spinal MRI is unremarkable in the majority of cases.2 T2/FLAIR hyperintensities can be observed in the medial temporal lobes especially in patients with cognitive deficit and seizures, and brainstem hyperintensities or cerebellar atrophy in patients presenting with ataxia. Focal (especially in the temporal regions) or diffuse slowing and sharp waves may be observed on electroencephalography. CASPR2 antibody-related encephalomyelitis are frequently associated with other autoimmune affections (including thyroiditis or myasthenia gravis), and paraneoplastic in a minority of cases (mainly related to thymoma).2 The most striking clinical feature in our case was the presence of rhythmic abdominal myoclonus resembling belly dance. Belly dancer myoclonus is a segmental myoclonus considered to be of spinal origin involving sometimes also diaphragm muscles. Lower limb myoclonus while standing or walking has been earlier reported as a movement disorder phenotype in CASPR2 antibody-related encephalomyelitis.3, 4 One patient with spinal myoclonus has been reported with clinical lower limb myoclonus associated with abdominal myoclonus only observed by electromyography.5 To the best of our knowledge, this is the first case of clinical abdominal myoclonus associated with CASPR2 antibodies. We would like to thank Drs Anne-Laurie Pinto and Sergio Muniz-Castrillo for the analysis of CSF samples. We would like to thank Dr Sarah Coudray for the attainment and interpretation of the electrophysiological data. (1) Research Project: A. Conception, B. Organization, C. Execution; (2) Statistical Analysis: A. Design, B. Execution, C. Review and Critique; (3) Manuscript: A. Writing of the first draft, B. Review and Critique. L.K.: 1A, 2C, 3A D.R.: 2C, 3B J.H.: 1C, 2B G.C.: 1A, 2C, 3A, 3B The present work respects ethical guidelines. The authors confirm that the approval of an institutional review board was not required for this work. Written consent was obtained for showing the patients' video. We confirm that we have read the Journal's position on issues involved in ethical publication and affirm that this work is consistent with those guidelines. The authors declare that there are no funding sources or conflicts of interest relevant to this work. The authors declare that there are no additional disclosures to report.

Serum antiganglioside antibodies in patients with autoimmune limbic encephalitis.

Ganglioside antibodies are identified not only in patients with inflammatory neuropathies but also several central nervous system disorders and paraneoplastic neuropathies. Our aim was to investigate whether ganglioside antibodies are found in autoimmune encephalitis patients and may function as a diagnostic and prognostic biomarker. Sera and cerebrospinal fluid (CSF) samples of 33 patients fulfilling the criteria for probable autoimmune encephalitis were collected within the first week of clinical manifestation. None of the patients had evident symptoms and findings of peripheral polyneuropathy. Well-characterized antineuronal and paraneoplastic antibodies were investigated in sera and CSF and antiganglioside (antiGM1, GM2, GM3, GD1a, GD1b, GT1b, and GQ1b) IgG and IgM antibodies were measured in sera using commercial immunoblots. Twenty-eight of 33 autoimmune encephalitis patients displayed antibodies against neuronal surface or onco-neural antigens with N-methyl-D-aspartate receptor (NMDAR), glutamic acid decarboxylase (GAD) and Hu antibodies being the most prevalent. While no antiganglioside IgG antibodies were found, 4 patients (2 anti-NMDAR+, 1 anti-GAD+ and 1 antibody negative) with autoimmune limbic encephalitis displayed anti-GM1, anti-GM2, anti-GM3 or anti-GQ1b IgM antibodies. There was no apparent association between antiganglioside positivity and clinical and demographic features. Serum ganglioside IgM antibodies may infrequently emerge during the clinical course of autoimmune limbic encephalitis without evident polyneuropathy. Absence of the IgG response suggests that these antibodies might have developed as a hyperacute immune response to neuro-axonal destruction. Nevertheless, potential impact of ganglioside antibodies on axonal degeneration and neuronal loss in limbic encephalitis pends to be further investigated.

What Are the Biomarkers for Immunotherapy in SCLC?

Small-cell lung cancer (SCLC) is an aggressive malignancy that exhibits a rapid doubling time, a high growth fraction, and the early development of widespread metastases. The addition of immune checkpoint inhibitors to first-line chemotherapy represents the first significant improvement of systemic therapy in several decades. However, in contrast to its effects on non-SCLC, the advantageous effects of immunotherapy addition are modest in SCLC. In particular, only a small number of SCLC patients benefit from immune checkpoint inhibitors. Additionally, biomarkers selection is lacking for SCLC, with clinical trials largely focusing on unselected populations. Here, we review the data concerning the major biomarkers for immunotherapy, namely, programmed death ligand 1 expression and tumour mutational burden. Furthermore, we explore other potential biomarkers, including the role of the immune microenvironment in SCLC, the role of genetic alterations, and the potential links between neurological paraneoplastic syndromes, serum anti-neuronal nuclear antibodies, and outcomes in SCLC patients treated with immunotherapy.

Common paraneoplastic neurological syndromes in Pakistan: Clinical and immunological aspects

To determine the frequency and clinical features associated with anti-neuronal antibodies in patients suspected of paraneoplastic neurological syndromes and autoimmune encephalitis in a tertiary care hospital in Islamabad, Pakistan.

Testing for Thyroid Peroxidase and Antineuronal Antibodies in Depression and Schizophrenia.

Dietary interventions and physical exercise may improve some symptoms in mental illnesses such as major depression and schizophrenia. Hashimoto's thyroiditis is a known risk factor for these conditions and is marked by the presence of circulating antibodies to thyroid peroxidase (TPO) and thyroglobulin (TG). This chapter presents a protocol to determine if patients with major depression or schizophrenia contain high circulating levels of these antibodies relative to healthy controls. We also describe a procedure testing for the presence of other circulating biomarkers related to brain function, including antibodies directly related to neuronal function. This analysis was performed by screening biochip mosaics of frozen tissue sections and transfected HEK293 cells expressing target antigens using patient and control sera. Finally, we describe a correlation analysis of these markers with symptom scores at baseline and after 6weeks treatment of the patients using antipsychotics or antidepressants as appropriate.

Update in Autoimmune Movement Disorders: Newly Described Antigen Targets in Autoimmune and Paraneoplastic Cerebellar Ataxia.

Movement disorders are a common feature of many antibody-associated neurological disorders. In fact, cerebellar ataxia is one of the most common manifestations of autoimmune neurological diseases. Some of the first autoantibodies identified against antigen targets include anti-neuronal nuclear antibody type 1 (ANNA-1 or anti-Hu) and Purkinje cell cytoplasmic antibody (PCA-1) also known as anti-Yo have been identified in paraneoplastic cerebellar degeneration. Historically these antibodies have been associated with an underlying malignancy; however, recently discovered antibodies can occur in the absence of cancer as well, resulting in the clinical syndrome of autoimmune cerebellar ataxia. The pace of discovery of new antibodies associated with autoimmune or paraneoplastic cerebellar ataxia has increased rapidly over the last few years, and pathogenesis and potential treatment options remains to be explored. Here we will review the literature on recently discovered antibodies associated with autoimmune and paraneoplastic cerebellar ataxia including adaptor protein-3B2 (AP3B2); inositol 1,4,5-trisphophate receptor type 1 (ITPR1); tripartite motif-containing (TRIM) proteins 9, 67, and 46; neurochondrin; neuronal intermediate filament light chain (NIF); septin 5; metabotropic glutamate receptor 2 (mGluR2); seizure-related 6 homolog like 2 (SEZ6L2) and homer-3 antibodies. We will review their clinical characteristics, imaging and CSF findings and treatment response. In addition, we will discuss two clinical case examples of autoimmune cerebellar ataxia.

Psychiatric Phenotypes of Pediatric Patients With Seropositive Autoimmune Encephalitis.

Patients with autoimmune encephalitis (AE) often present with symptoms that are broadly characterized as psychiatric or behavioral, yet little attention is given to the precise symptomatology observed. We sought to more fully define the psychiatric symptoms observed in patients with anti-N-methyl-D-aspartate receptor (NMDAR), anti-glutamic-acid-decarboxylase 65 (GAD65), and anti-voltage-gated-potassium-channel complex (VGKC) antibody-mediated AE using the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition nomenclature. We present a case series (n = 25) using a retrospective chart review of 225 patients evaluated for AE in a tertiary care academic medical center between 2014 and 2018. The included patients were ≤18 years old with anti-NMDAR AE (n = 13), anti-GAD65 AE (n = 7), or anti-VGKC AE (n = 5). The frequency of neuropsychiatric symptoms present at the onset of illness and time to diagnosis were compared across groups. Psychiatric symptoms were seen in 92% of patients in our cohort. Depressive features (72%), personality change (64%), psychosis (48%), and catatonia (32%) were the most common psychiatric symptoms exhibited. On average, patients experienced impairment in ≥4 of 7 symptom domains. No patients had isolated psychiatric symptoms. The average times to diagnosis were 1.7, 15.5, and 12.4 months for anti-NMDAR AE, anti-GAD65 AE, and anti-VGKC AE, respectively (P < .001). The psychiatric phenotype of AE in children is highly heterogenous. Involving psychiatry consultation services can be helpful in differentiating features of psychosis and catatonia, which may otherwise be misidentified. Patients presenting with psychiatric symptoms along with impairments in other domains should prompt a workup for AE, including testing for all known antineuronal antibodies.

Autoimmune Encephalitis: Report of Two Pediatric Cases

Background: Autoimmune encephalitis (AIE) with neural cell autoantibodies is a treatable category of non-viral encephalitis in children and adolescents which presents with neuropsychiatric manifestations. Anti-N-methyl- D-aspartate receptor encephalitis, the most common identified type of AIE, is more frequent than individual viral encephalitis in young patients. Early diagnosis and treatment of the disease have been associated with improvement in the majority of patients.Case Report: we report two pediatric cases with acute neuropsychiatric presentations in whom the diagnosis of AIE was proved based on the cerebrospinal fluid (CSF) antineuronal antibodies in one and on clinical and paraclinical grounds in another seronegative patient. Immunotherapy in both patients resulted in improvement. No underlying tumor was found in patients.Pediatricians should be aware of manifestations, investigations, and treatment of AIE and consider it as the differential diagnosis of encephalitis.