Akihiro Mukaino

Antibodies to myelin oligodendrocyte glycoprotein in idiopathic optic neuritis

Objectives To investigate the differences of clinical features, cerebrospinal fluid (CSF), MRI findings and response to steroid therapies between patients with optic neuritis (ON) who have myelin oligodendrocyte glycoprotein (MOG) antibodies and those who have seronegative ON. Setting We recruited participants in the department of neurology and ophthalmology in our hospital in Japan. Methods We retrospectively evaluated the clinical features and response to steroid therapies of patients with ON. Sera from patients were tested for antibodies to MOG and aquaporin-4 (AQP4) with a cell-based assay. Participants Between April 2009 and March 2014, we enrolled serial 57 patients with ON (27 males, 30 females; age range 16–84 years) who ophthalmologists had diagnosed as having or suspected to have ON with acute visual impairment and declined critical flicker frequency, abnormal findings of brain MRI, optical coherence tomography and fluorescein fundus angiography at their onset or recurrence. We excluded those patients who fulfilled the diagnostic criteria of neuromyelitis optica (NMO)/NMO spectrum disorders (NMOSD), MS McDonalds criteria, and so on. Finally we defined 29 patients with idiopathic ON (14 males, 15 females, age range 16–84 years). Results 27.6% (8/29) were positive for MOG antibodies and 3.4% (1/29) were positive for AQP4. Among the eight patients with MOG antibodies, five had optic pain (p=0.001) and three had prodromal infection (p=0.179). Three of the eight MOG-positive patients showed significantly high CSF levels of myelin basic protein (p=0.021) and none were positive for oligoclonal band in CSF. On MRIs, seven MOG-positive patients showed high signal intensity on optic nerve, three had a cerebral lesion and one had a spinal cord lesion. Seven of the eight MOG-positive patients had a good response to steroid therapy. Conclusions Although not proving primary pathogenicity of anti-MOG antibodies, the present results indicate that the measurement of MOG antibodies is useful in diagnosing and treating ON.

Clinical Features of Autoimmune Autonomic Ganglionopathy and the Detection of Subunit-Specific Autoantibodies to the Ganglionic Acetylcholine Receptor in Japanese Patients

Autoimmune autonomic ganglionopathy (AAG) is a rare acquired channelopathy that is characterized by pandysautonomia, in which autoantibodies to ganglionic nicotinic acetylcholine receptors (gAChR) may play a central role. Radioimmunoprecipitation (RIP) assays have been used for the sensitive detection of autoantibodies to gAChR in the serum of patients with AAG. Here, we developed luciferase immunoprecipitation systems (LIPS) to diagnose AAG based on IgGs to both the α3 and β4 gAChR subunits in patient serum. We reviewed the serological and clinical data of 50 Japanese patients who were diagnosed with AAG. With the LIPS testing, we detected anti-α3 and -β4 gAChR antibodies in 48% (24/50) of the patients. A gradual mode of onset was more common in the seropositive group than in the seronegative group. Patients with AAG frequently have orthostatic hypotension and upper and lower gastrointestinal tract symptoms, with or without anti-gAChR. The occurrence of autonomic symptoms was not significantly different between the seropositive and seronegative group, with the exception of achalasia in three patients from the seropositive group. In addition, we found a significant overrepresentation of autoimmune diseases in the seropositive group and endocrinological abnormalities as an occasional complication of AAG. Our results demonstrated that the LIPS assay was a useful novel tool for detecting autoantibodies against gAChR in patients with AAG.

Association between Anti-Ganglionic Nicotinic Acetylcholine Receptor (gAChR) Antibodies and HLA-DRB1 Alleles in the Japanese Population

Background/Aims Anti-ganglionic nicotinic acetylcholine receptor (gAChR) antibodies are observed in autoimmune diseases, as well as in patients with autoimmune autonomic ganglionopathy. However, the genetic background of anti-gAChR antibodies is unclear. Here, we investigated HLA alleles in autoimmune hepatitis (AIH) patients with or without anti-gAChR antibodies. Methodology/Principal Findings Genomic DNA from 260 patients with type-1 autoimmune hepatitis (AIH) were genotyped for HLA-A, B, DRB1, and DQB1 loci. Anti-gAChR antibodies in the sera form AIH patients were measured using the luciferase immunoprecipitation system, and examined allelic association in patients with or without anti-gAChR antibodies. Methodology/ Methods We detected anti-α3 or -β4 gAChR antibodies in 11.5% (30/260) of patients with AIH. Among AIH patients there was no significant association between HLA-A, B DQB1 alleles and the positivity for anti-gAChR antibodies. Whereas the HLA-DRB1*0403 allele showed a significantly increased frequency in AIH patients with anti-gAChR antibodies compared with those without anti-gAChR antibodies. Conclusions/Significance The frequency of the HLA-DRB1*0403 allele differed among Japanese patients with AIH according to the presence or absence of anti-gAChR antibodies. Our findings suggest that particular HLA class II molecules might control the development of anti-gAChR antibodies in the autoimmune response to gAChR.

Ganglionic acetylcholine receptor autoantibodies in patients with autoimmune diseases including primary biliary cirrhosis

Abstract Objectives: Autonomic dysfunction is closely associated with autoimmune diseases (AID) including primary biliary cirrhosis (PBC). The objective of this study was to determine the prevalence of anti-ganglionic (nicotinic) acetylcholine receptor (gAChR) antibodies in patients with AID. Methods: We determined the presence of gAChR antibodies in serum samples from 146 patients (systemic lupus erythematosus [SLE] = 32; rheumatoid arthritis [RA] = 43; systemic sclerosis [SSc] = 38; PBC= 33) without information regarding autonomic symptoms, as well as 34 patients with other neurological diseases [OND], and 73 healthy controls [HC]. We specifically analyzed sera for anti-gAChRα3 and -β4 antibodies using the luciferase immunoprecipitation system (LIPS) assay. Results: LIPS assay detected anti-gAChRα3 and -β4 antibodies in the sera from patients with SLE (12.5%, 4/32), RA (18.6%, 8/43), SSc (13.2%, 5/38), PBC (9.1%, 3/33), OND (2.9%, 1/34), and HC (0.0%, 1/73). There were no significant correlations between the levels of anti-gAChRα3 and -β4 antibodies, and the total titers of autoantibodies in AID. Conclusions: The results demonstrated a significant prevalence of anti-gAChR antibodies in patients with AID, which is independent of the production of other autoantibodies in patients with autoimmune diseases. These anti-gAChR antibodies could mediate the autonomic dysfunction involved in the autoimmune mechanisms of AID.

Insights from the ganglionic acetylcholine receptor autoantibodies in patients with Sjögren’s syndrome

Abstract Objective: It is not known whether autonomic neuropathy is a feature of Sjögren’s syndrome (SS) or whether it is related to circulating antiganglionic acetylcholine receptor (gAChR) antibodies. The goal of the present study was to investigate the autonomic dysfunction in patients with SS and the associations between autonomic dysfunction, anti-gAChR antibodies, and clinical features of SS. Methods: (1) The first observational study tested for the presence of gAChR antibodies in the serum samples from 39 patients with SS (absent information regarding autonomic symptoms) and healthy volunteers. (2) In the second study, serological and clinical data from 10 Japanese patients diagnosed with SS were reviewed. These patients showed autonomic dysfunction, and luciferase immunoprecipitation systems (LIPS) test was conducted to detect anti-α3 and anti-β4 gAChR antibodies. (3) In the final analysis, we combined the data of seropositive SS patients with autonomic symptom from the first study with all of the patients from the second study, and analyzed the clinical features. Results: (1) The LIPS assay revealed that anti-gAChRα3 and anti-gAChRβ4 antibodies were detected in the sera from patients with SS (23.1%, 9/39). Five of nine SS patients had autonomic symptoms. (2) Anti-α3 and anti-β4 gAChR antibodies were also detected in 80.0% (8/10) of patients with SS with autonomic symptoms. Six of the ten patients were diagnosed as having SS after neurological symptoms developed. These seropositive patients had predominant and severe autonomic symptoms and were diagnosed with autonomic neuropathy. (3) Thirteen of fifteen SS patients with autonomic symptoms (86.7%) were seropositive for anti-gAChR antibodies, and we confirmed sicca complex, orthostatic hypotension, upper and lower gastrointestinal (GI) symptoms, and bladder dysfunction at high rates. Conclusion: The present results suggest the possibility of anti-gAChR antibodies aiding the diagnostics of SS with autonomic dysfunction.

Ganglionic acetylcholine receptor autoantibodies in patients with Guillain-Barré syndrome.

OBJECTIVES Although standardized autonomic tests are useful for diagnosing autonomic failure in patients with Guillain-Barré syndrome (GBS), they cannot be used as predictive markers. Thus, serological markers may correctly identify patients with GBS who are at risk for autonomic dysfunction. METHODS We validated a luciferase immunoprecipitation system that detects IgG antibodies in patient serum that specifically bind to the α3 or β4 subunits of ganglionic neuronal nicotinic acetylcholine receptors (gAChR). We then used luciferase-conjugated ligands specific to antibodies against two gAChR subunits to test 79 sera samples from patients with GBS, 34 from subjects with other neurological diseases (OND), and 73 from healthy controls (HC). 1) In the first analysis, patients were classified into two groups according to the presence or absence of autonomic symptoms (AS). We compared the frequency of the anti-gAChR antibodies between these two groups (AS+ and AS-). 2) In the second analysis, furthermore, patients were classified depending on the presence or absence of anti-glycolipid antibodies (AGA). We compared the frequency of the anti-gAChR antibodies between the four categories of GBS (AS+/AGA+, AS+/AGA-, AS-/AGA+, and AS-/AGA-), OND, and HC. RESULTS Eight subjects with GBS were positive for α3 subunits, while one was positive for β4 subunits. Anti-α3 and -β4 gAChR antibodies were also detected in 13.6% of AS+ GBS group in the first analysis. Two of 35 patients in AS-GBS group were seropositive for the anti-gAChR antibodies and AGA in the second analysis. Patients with GBS that were positive for serum antibodies to the α3 and/or β4 subunits of gAChRs showed a range of clinical features including AS and AGA. CONCLUSIONS Patients with GBS may have circulating antibodies against gAChR, which may contribute to the autonomic dysfunction associated with this disease.

Extra-autonomic manifestations in autoimmune autonomic ganglionopathy: a Japanese survey

Autoimmune autonomic ganglionopathy (AAG) is an acquired immune-mediated disorder that leads to autonomic failure. The disorder is associated with autoantibodies (Abs) to the ganglionic nicotinic acetylcholine receptor (gAChR).1 Previously, we developed a luciferase immunoprecipitation systems (LIPS) protocol to aid in the diagnosis of AAG based on serum levels of immunoglobulin G (IgG) to the α3 and β4 gAChR subunits.2 We subsequently observed that AAG is associated with an overrepresentation of autoimmune diseases and endocrine disorders.2 Furthermore, Hayashi et al 3 reviewed 29 Japanese case reports of AAG and pandysautonomia and observed that Japanese patients with AAG tended to exhibit additional coughing episodes/psychiatric symptoms when compared to patients in Western countries. Gibbons et al 4 reported some patients with AAG demonstrated reversible cognitive impairment. The present study aims to elucidate the prevalence of extra-autonomic manifestations including psychiatric symptoms in 80 Japanese patients with AAG who were seropositive for anti-gAChR Abs. ### Ethical approval All participants provided written, informed consent to participate in the study. The Ethics Committee of Nagasaki Kawatana Medical Center approved this study. ### Study population Serum samples from 946 patients with autonomic symptoms were obtained from general and teaching hospitals throughout Japan between January 2012 and April 2016 (mean age: 51±22 years; 488 men and 458 women). Clinical diagnoses were …

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‐gAChRα3 and β4 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.

Novel anti-suprabasin antibodies may contribute to the pathogenesis of neuropsychiatric systemic lupus erythematosus

Neuropsychiatric systemic lupus erythematosus (NPSLE) is often difficult to diagnose and distinguish from other diseases, because no NPSLE-specific antibodies have been identified. We developed a novel proteomic strategy for identifying and profiling antigens in immune complexes in the cerebrospinal fluid (CSF), and applied this strategy to 26 NPSLE patients. As controls, we also included 25 SLE patients without neuropsychiatric manifestations (SLE), 15 with relapsing remitting multiple sclerosis (MS) and 10 with normal pressure hydrocephalus (NPH). We identified immune complexes of suprabasin (SBSN) in the CSF of the NPSLE group. The titer of anti-SBSN antibodies was significantly higher in the CSF of the NPSLE group compared to those of the SLE, MS and NPH groups. Microarray data showed that the senescence and autophagy pathways were significantly changed in astrocytes exposed to anti-SBSN antibodies. Our findings indicate that SBSN could be a novel autoantibody for the evaluation of suspected NPSLE.

Anti-ganglionic AChR antibodies in Japanese patients with motility disorders

BackgroundThe existence of several autoantibodies suggests an autoimmune basis for gastrointestinal (GI) dysmotility. Whether GI motility disorders are features of autoimmune autonomic ganglionopathy (AAG) or are related to circulating anti-ganglionic acetylcholine receptor (gAChR) antibodies (Abs) is not known. The aim of this study was to determine the associations between autonomic dysfunction, anti-gAChR Abs, and clinical features in patients with GI motility disorders including achalasia and chronic intestinal pseudo-obstruction (CIPO).MethodsFirst study: retrospective cohort study and laboratory investigation. Samples from 123 patients with seropositive AAG were obtained between 2012 and 2017. Second study: prospective study. Samples from 28 patients with achalasia and 14 patients with CIPO were obtained between 2014 and 2016, and 2013 and 2017, respectively. In the first study, we analyzed clinical profiles of seropositive AAG patients. In the second study, we compared clinical profiles, autonomic symptoms, and results of antibody screening between seropositive, seronegative achalasia, and CIPO groups.ResultsIn the first study, we identified 10 patients (8.1%) who presented with achalasia, or gastroparesis, or paralytic ileus. In the second study, we detected anti-gAChR Abs in 21.4% of the achalasia patients, and in 50.0% of the CIPO patients. Although patients with achalasia and CIPO demonstrated widespread autonomic dysfunction, bladder dysfunction was observed in the seropositive patients with CIPO as a prominent clinical characteristic of dysautonomia.ConclusionsThese results demonstrate a significant prevalence of anti-gAChR antibodies in patients with achalasia and CIPO. Anti-gAChR Abs might mediate autonomic dysfunction, contributing to autoimmune mechanisms underlying these GI motility disorders.