Anti-Kv1.4 Antibody Without Myasthenia Gravis: A Rare Cause of Autoimmune Myocarditis and Myositis.

Anti-Kv1.4 antibody is often detected in thymoma-associated myasthenia gravis patients with anti-acetylcholine receptor antibody. Herein, we describe 2 patients with concurrent myocarditis and myositis. In both cases, anti-Kv1.4 antibody was positive despite the absence of thymoma and anti-acetylcholine receptor antibody, and immunosuppressants eventually resolved their symptoms and cardiac function. (Level of Difficulty: Advanced.).

A novel murine model of autoimmune dysautonomia by α3 nicotinic acetylcholine receptor immunization.

We aimed to establish a novel murine model of autoimmune autonomic ganglionopathy (AAG), which represents autoimmune dysautonomia, associated with MHC class II to understand its pathomechanism and the pathogenicity of nicotinic acetylcholine receptor (nAChR) antibodies. The amino acid sequence of the mouse nAChRα3 protein was analyzed using an epitope prediction tool to predict the possible MHC class II binding mouse nAChRα3 peptides. We focused on two nAChRα3 peptides in the extracellular region, and experimental AAG (EAAG) was induced by immunization of C57BL/6 mice with these two different peptides. EAAG mice were examined both physiologically and histologically. Mice with EAAG generated nAChRα3 antibodies and exhibited autonomic dysfunction, including reduced heart rate, excessive fluctuations in systolic blood pressure, and intestinal transit slowing. Additionally, we observed skin lesions, such as alopecia and skin ulcers, in immunized mice. Neuronal cell density in the sympathetic cervical ganglia in immunized mice was significantly lower than that in control mice at the light microscopic level. We interpreted that active immunization of mice with nAChRα3 peptides causes autonomic dysfunction similar to human AAG induced by an antibody-mediated mechanism. We suggested a mechanism by which different HLA class II molecules might preferentially affect the nAChR-specific immune response, thus controlling diversification of the autoantibody response. Our novel murine model mimics AAG in humans and provides a useful tool to investigate its pathomechanism.

Histopathological Features of Gerhardt Syndrome in a Patient With Multiple System Atrophy: An Autopsy Case Report.

Multiple system atrophy (MSA) is a progressive neurodegenerative disease characterized by autonomic failure, parkinsonism, and cerebellar ataxia. Gerhardt syndrome, which is inspiratory dyspnea with laryngeal stridor associated with dysfunction of the vocal folds, is a frequent and fatal complication of MSA. A 59-year-old man with a six-year history of MSA presented with ataxia and dysarthria. He also had dyspnea and stridor, which had worsened in the last three months, and died from respiratory distress. Autopsy revealed neurogenic group atrophy of the posterior cricoarytenoid (PCA) muscle, which suggested that laryngeal nerve damage caused abductor vocal fold paralysis in addition to cerebellar and brainstem atrophy with glial cytoplasmic inclusions. Our histopathological findings suggest that Gerhardt syndrome may be associated with neurogenic atrophy of the laryngeal abductor muscle (PCA muscle) of the vocal folds.

[Subdural hematoma with reversible cerebral vasoconstriction syndrome: a case report].

A 71-year-old man had persistent cervical pain secondary to thunderclap headache during sleep. MRI conducted the next morning revealed subdural hematoma and convexity subdural hemorrhage on the right occipital region, and the patient was hospitalized. MRA showed vascular narrowing in the bilateral PCA. Follow-up MRA on day 8 of admission showed aggravated vascular narrowing of PCA, indicative of reversible cerebral vasoconstriction syndrome (RCVS). The patient was treated with a calcium-channel antagonist. Post-discharge MRA showed improvement of PCA narrowing, and the diagnosis of RCVS was confirmed.

Binasal hemianopia caused by bilateral optic perineuritis due to sarcoidosis.

•We describe the first case of binasal hemianopia due to bilateral optic perineuritis.•Bilateral optic perineuritis should be considered as a causative disease of binasal hemianopia.•Early diagnosis of optic perineuritis is crucial to avoid irreversible visual impairment.

gAChR antibodies in children and adolescents with acquired autoimmune dysautonomia in Japan.

OBJECTIVE: Patients with acquired autonomic dysfunction may have antibodies specific to the ganglionic nicotinic acetylcholine receptor (gAChR). However, the clinical features of children and adolescents with acquired autonomic dysfunction (AAD) remain unclear. This study aimed to determine the clinical features of pediatric patients with acquired autonomic dysfunction. METHODS: This study retrospectively examined a series of patients of AAD with serum gAChR antibodies who were referred to our laboratory for antibody testing between January 2012 and April 2019. The study included 200 patients (<20 years, 20 cases; ≥20 years, 175 cases) with clinical features of AAD. RESULTS: Upon comparing pediatric and adult patients, we found that antecedent infection and autonomic symptoms at onset with gastrointestinal symptoms occurred more frequently in children with AAD. We confirmed that four children (20.0%) met the diagnostic criteria for postural orthostatic tachycardia syndrome (POTS). A significantly higher number of children than adults had POTS (P = 0.002). In addition, upper GI dysfunction was more prevalent in children than in adults (P = 0.042). In particular, nausea and vomiting occurred in 60.0% of children with AAD and in 21.1% of adults (P < 0.001). The frequency of paralytic ileus was significantly higher in children with AAD (20.0%) relative to adults (6.3%) (P = 0.030). Regarding extra-autonomic manifestations, encephalopathy was more frequent in children (15.0%) than in adults (1.1%) (P < 0.001). INTERPRETATION: Pediatric AAD patients have their own clinical characteristics, and these features may be unique to children and adolescents.

Antibodies to the α3 subunit of the ganglionic-type nicotinic acetylcholine receptors in patients with autoimmune encephalitis.

Since autonomic dysfunction is closely associated with autoimmune encephalitis (AE), the objective of this study was to determine the autonomic symptoms and the prevalence of anti-α3 subunit of the ganglionic-type nicotinic acetylcholine receptor (gAChRα3) antibodies in the patients with AE. We reviewed the clinical features of 19 AE patients, and specifically analyzed sera for anti-gAChRα3 antibodies using the luciferase immunoprecipitation system (LIPS) assay. Cardiovascular autonomic symptoms were found to be common in patients with AE, and hypersalivation was seen only in patients with NMDAR encephalitis. LIPS detected anti-gAChRα3 antibodies in the sera from patients with AE (5/29, 26%). This study is the first to demonstrate that clinical characteristics including autonomic symptoms of AE patients with seropositivity for gAChR autoantibodies. It will be important to verify the role of gAChR antibodies in autonomic dysfunction and brain symptoms to clarify the pathogenesis of AE.

A Randomized Phase 2 Trial of Antibiotic Prophylaxis Versus No Intervention for Muscle Biopsy in A Neurology Department.

Muscle biopsy can be used to confirm the diagnosis of neuromuscular diseases. However, it is unclear whether antibiotic prophylaxis prior to muscle biopsy is needed to prevent surgical site infection (SSI). We are conducting a phase 2, single-center, open-labeled, prospective randomized trial to clarify the need for antibiotic prophylaxis in patients at low risk for SSI undergoing muscle biopsy. Patients will be randomized to an antibiotic prophylaxis group or a control group, and the incidence of SSI will be compared between the groups. Our findings will clarify the need for antibiotic prophylaxis in this patient population.

Ganglionic Acetylcholine Receptor Antibodies and Autonomic Dysfunction in Autoimmune Rheumatic Diseases.

Autonomic neuropathy has been reported in autoimmune rheumatic diseases (ARD) including Sjögren's syndrome, systemic sclerosis, rheumatoid arthritis, and systemic lupus erythematosus. However, the pathophysiological mechanism underlying autonomic dysfunction remains unknown to researchers. On the other hand, autoimmune autonomic ganglionopathy (AAG) is an acquired immune-mediated disorder, which causes dysautonomia that is mediated by autoantibodies against ganglionic acetylcholine receptors (gAChRs). The purpose of this review was to describe the characteristics of autonomic disturbance through previous case reports and the functional tests used in these studies and address the importance of anti-gAChR antibodies. We have established luciferase immunoprecipitation systems to detect antibodies against gAChR in the past and determined the prevalence of gAChR antibodies in various autoimmune diseases including AAG and rheumatic diseases. Autonomic dysfunction, which affects lower parasympathetic and higher sympathetic activity, is usually observed in ARD. The anti-gAChR antibodies may play a crucial role in autonomic dysfunction observed in ARD. Further studies are necessary to determine whether anti-gAChR antibody levels are correlated with the severity of autonomic dysfunction in ARD.

A comprehensive analysis of the clinical characteristics and laboratory features in 179 patients with autoimmune autonomic ganglionopathy.

The clinical importance of autoantibodies against the ganglionic acetylcholine receptor (gAChR) remains to be fully elucidated. We aimed to identify the clinical characteristics of autoimmune autonomic ganglionopathy (AAG) in patients with gAChR autoantibodies. For this cohort investigation, serum samples were obtained from patients with AAG between 2012 and 2018 in Japan. We measured the levels of autoantibodies against gAChRα3 and gAChRß4 and evaluated clinical features, as well as assessing the laboratory investigation results among the included patients. A total of 179 patients tested positive for antibodies, including 116 gAChRα3-positive, 13 gAChRß4-positive, and 50 double antibody-positive patients. Seropositive AAG patients exhibited widespread autonomic dysfunction. Extra-autonomic manifestations including sensory disturbance, central nervous system involvement, endocrine disorders, autoimmune diseases, and tumours were present in 118 patients (83%). We observed significant differences in the frequencies of several autonomic and extra-autonomic symptoms among the three groups. Our 123I-metaiodobenzylguanidine myocardial scintigraphy analysis of the entire cohort revealed that the heart-to-mediastinum ratio had decreased by 80%. The present study is the first to demonstrate that patients with AAG who are seropositive for anti-gAChRß4 autoantibodies exhibit unique autonomic and extra-autonomic signs. Decreased cardiac uptake occurred in most cases, indicating that 123I- metaiodobenzylguanidine myocardial scintigraphy may be useful for monitoring AAG. Therefore, our findings indicate that gAChRα3 and gAChRß4 autoantibodies cause functional changes in postganglionic fibres in the autonomic nervous system and extra-autonomic manifestations in seropositive patients with AAG.

Cytometric cell-based assays for anti-striational antibodies in myasthenia gravis with myositis and/or myocarditis.

The purposes of the present study were to identify anti-striational antibodies in myasthenia gravis (MG) patients with myositis and/or myocarditis using a combination of cell-based assays and flow cytometry (cytometric cell-based assays) and to describe the main clinical implications. Among 2,609 stored samples collected from all over Japan between 2003 and 2016, we had serum samples from 30 MG patients with myositis and/or myocarditis. Cytometric cell-based assays with titin, ryanodine receptor, and voltage-gated Kv1.4 were performed. Autoantibodies were determined by differences in phycoerythin fluorescence between the 293F cells and titin-transfected cells. MG patients with myositis and/or myocarditis as well as late-onset and thymoma-associated MG had anti-titin, anti-ryanodine receptor, and anti-Kv1.4 antibodies. In contrast, patients with early-onset MG, those with other myopathies and healthy controls did not have anti-titin or anti-Kv1.4 antibodies with some exceptions, but they possessed anti-ryanodine receptor antibodies. Thirty MG patients with myositis and/or myocarditis showed a severe generalized form, and 21 of them had thymoma. Anti-titin and anti-Kv1.4 antibodies were found in 28 (93%) and 15 (50%) patients, respectively, and all patients had at least one of these antibodies. Cytometric cell-based assays thus demonstrated that anti-striational antibodies are biomarkers of MG with myositis and/or myocarditis.

The Risks and Benefits of Immune Checkpoint Blockade in Anti-AChR Antibody-Seropositive Non-Small Cell Lung Cancer Patients.

BACKGROUND: Anti-programmed cell death 1 (PD-1) monoclonal antibodies (Abs) unleash an immune response to cancer. However, a disruption of the immune checkpoint function by blocking PD-1/PD-ligand 1(PD-L1) signaling may trigger myasthenia gravis (MG) as a life-threatening immune-related adverse event. MG is a neuromuscular disease and is closely associated with being positive for anti-acetylcholine receptor (anti-AChR) Abs, which are high specific and diagnostic Abs for MG. METHODS: A 72-year-old man was diagnosed with chemotherapy-refractory lung squamous cell carcinoma and nivolumab was selected as the third-line regimen. We describe the first report of an anti-AChR Ab-seropositive lung cancer patient achieving a durable complete response (CR) to an anti-PD-1 antibody therapy. To further explore this case, we performed multiplex immunofluorescence analysis on a pretreatment tumor. RESULTS: The patient achieved a durable CR without developing MG. However, the levels of anti-AChR Abs were elevated during two years of anti-PD-1 antibody therapy. The tumor of the subclinical MG patient had high PD-L1 expression and an infiltrated⁻inflamed tumor immune microenvironment. CONCLUSIONS: This study suggests that immune checkpoint inhibitors can be safely used and provide the benefits for advanced cancer patients with immunologically 'hot' tumor even if anti-AChR Abs are positive. Although careful monitoring clinical manifestation in consultation with neurologist is needed, immune checkpoint inhibitors should be considered as a treatment option for asymptomatic anti-AChR Ab-seropositive cancer patients.

CSF TACI and BAFF levels in patients with primary CNS lymphoma as novel diagnostic biomarkers.

We used an enzyme-linked immunosorbent assay to measure pretreatment B cell-activating factor belonging to the tumour necrosis factor family (BAFF) and transmembrane activator and CAML-interactor (TACI) levels in CSF and serum collected from patients with primary central nervous system lymphoma (PCNSL) and control groups. The decision tree analysis of CSF TACI and BAFF levels for patients with a PCNSL diagnosis showed 100% sensitivity and 100% specificity when we attempted to differentiate PCNSL from glioblastoma and CNS inflammatory diseases. The combination of CSF TACI and BAFF levels may thus be a novel and useful diagnostic biomarker of PCNSL.

Immune checkpoint inhibitors in the onset of myasthenia gravis with hyperCKemia.

Immune checkpoint inhibitors sometimes cause neuromuscular adverse events. Although a few cases of myasthenia gravis with hyperCKemia triggered by immune checkpoint inhibitors have been described, conclusive evidence remains limited. We conducted a systematic review of published cases of myasthenia gravis with hyperCKemia related to immune checkpoint inhibitors. Moreover, we tested anti-striational antibodies in the case of myasthenia gravis with myositis after nivolumab administration. We located 17 published case reports. Anti-striational antibodies were tested in six cases and five cases were positive. Our systematic analyses revealed poor prognosis in myasthenia gravis combined hyperCKemia with immune checkpoint inhibitors.

Autoimmune autonomic ganglionopathy: an update on diagnosis and treatment.

INTRODUCTION: Autoimmune autonomic ganglionopathy (AAG) is an acquired immune-mediated disorder that leads to autonomic failure. The disorder is associated with autoantibodies to the ganglionic nicotinic acetylcholine receptor (gAChR). We subsequently reported that AAG is associated with an overrepresentation of psychiatric symptoms, sensory disturbance, autoimmune diseases, and endocrine disorders. Area covered: The aim of this review was to describe AAG and highlight its pivotal pathophysiological aspects, clinical features, laboratory examinations, and therapeutic options. Expert commentary: AAG is a complex neuroimmunological disease, these days considered as an autonomic failure with extra-autonomic manifestations (and various limited forms). Further comprehension of the pathophysiology of this disease is required, especially the mechanisms of the extra-autonomic manifestations should be elucidated. There is the possibility that the co-presence of antibodies that were directed against the other subunits in both the central and peripheral nAChRs in the serum of the AAG patients. Some patients improve with immunotherapies such as IVIg and/or corticosteroid and/or plasma exchange. 123I-MIBG myocardial scintigraphy may be a useful tool to monitor the therapeutic effects of immunotherapies.

Trousseau's syndrome triggered by an immune checkpoint blockade in a non-small cell lung cancer patient.

PD-1 blockade therapy activates T cells by blocking the interaction between PD-1 and PD-L1 and promotes IFN-γ and Th1 cytokine production. In turn, IFN-γ and Th1 cytokines produced by activated T cells promote TF synthesis in monocytes/macrophages, which results in hypercoagulability leading to thrombosis.

Autoimmune postural orthostatic tachycardia syndrome.

The aim of this study was to evaluate the association between postural orthostatic tachycardia syndrome (POTS) and circulating antiganglionic acetylcholine receptor (gAChR) antibodies. We reviewed clinical assessments of Japanese patients with POTS, and determined the presence of gAChR antibodies in serum samples from those patients. Luciferase immunoprecipitation systems detected anti-gAChR α3 and ß4 antibodies in the sera from POTS (29%). Antecedent infections were frequently reported in patients in POTS patients. Moreover, autoimmune markers and comorbid autoimmune diseases were also frequent in seropositive POTS patients. Anti-gAChR antibodies were detectable in significant number of patients with POTS, and POTS entailed the element of autoimmune basis.

Involvement of Macrophages in the Pathogenesis of Familial Amyloid Polyneuropathy and Efficacy of Human iPS Cell-Derived Macrophages in Its Treatment.

We hypothesized that tissue-resident macrophages in familial amyloid polyneuropathy (FAP) patients will exhibit qualitative or quantitative abnormalities, that may accelerate transthyretin (TTR)-derived amyloid deposition. To evaluate this, we examined the number and subset of tissue-resident macrophages in heart tissue from amyloid-deposited FAP and control patients. In both FAP and control patients, tissue-resident macrophages in heart tissue were all Iba+/CD163+/CD206+ macrophages. However, the number of macrophages was significantly decreased in FAP patients compared with control patients. Furthermore, the proportion of intracellular TTR in CD14+ monocytes was reduced in peripheral blood compared with healthy donors. Based on these results, we next examined degradation and endocytosis of TTR in human induced pluripotent stem (iPS) cell-derived myeloid lineage cells (MLs), which function like macrophages. iPS-MLs express CD163 and CD206, and belong to the inhibitory macrophage category. In addition, iPS-MLs degrade both native and aggregated TTR in a cell-dependent manner in vitro. Further, iPS-MLs endocytose aggregated, and especially polymerized, TTR. These results suggest that decreased tissue-localized macrophages disrupt clearance of TTR-derived amyloid deposits, leading to progression of a pathological condition in FAP patients. To improve this situation, clinical application of pluripotent stem cell-derived MLs may be useful as an approach for FAP therapy.

Thomsen disease with ptosis and abnormal MR findings.

Myotonia congenita is a non-dystrophic skeletal muscle disorder characterized by muscle stiffness and an inability of the muscle to relax after voluntary contraction caused by a mutation in the gene encoding skeletal muscle chloride channel-1 (CLCN1). We encountered a case of Thomsen disease with ptosis. A short tau inversion recovery MR imaging demonstrated high-intensity lesions in the levator palpebrae superioris muscles. Molecular genetic testing revealed a heterozygosity for the c.1439C>A (p.P480H) mutation in the CLCN1 gene. The expression level of ClC-1 was significantly reduced on the sarcolemma of the biceps brachii muscle from the patient, compared with that from healthy volunteer. Functional analysis of the p.P480H mutation is required for further elucidating the pathogenesis of Thomsen disease.