Liver Cancer with Overlapping Myasthenia Gravis, Myocarditis, Seronegative Autoimmune Autonomic Ganglionopathy, and Myositis Symptoms Induced by Atezolizumab.

An 83-year-old man with hepatocellular carcinoma developed muscle weakness, ptosis, and dyspnea 3 weeks after receiving atezolizumab. Soon after, mechanical ventilation was initiated, which was followed by marked blood pressure spikes. The levels of creatine kinase and troponin-I were significantly elevated, and acetylcholine receptor antibodies were positive. The patient was diagnosed with immune checkpoint inhibitor (ICI)-induced myositis, myasthenia gravis (MG), myocarditis, and suspected autoimmune autonomic ganglionopathy (AAG). After immunotherapy, the serum markers and blood pressure normalized, and he was weaned from the ventilator after five months. To our knowledge, this is the first reported case of AAG secondary to ICI-induced myositis, MG, and myocarditis.

Dysautonomia associated with immune checkpoint inhibitors.

OBJECTIVE: The purpose of this study is to report the clinical characteristics of dysautonomia associated with immune checkpoint inhibitors (ICIs). METHODS: We reported two patients with autoimmune autonomic ganglionopathy (AAG) occurring as immune-related adverse events (irAEs). We also performed a review of previous case reports presenting dysautonomia during ICI therapy. Moreover, we conducted pharmacovigilance analyses using the US Food and Drug Administration Adverse Events Reporting System (FAERS) to investigate dysautonomia associated with ICI. RESULTS: Two patients in our care developed both AAG and autoimmune encephalitis following ICI therapy for lung cancers. We comprehensively reviewed 13 published cases (M:F = 11:2, mean onset age of 53 years) with ICI-associated dysautonomia including AAG (n = 3) and autonomic neuropathy (n = 10). Of these, ICI monotherapy was performed in seven and combination ICI use in six. In 6 of 13 patients, dysautonomia appeared within one month after the start of ICIs. Orthostatic hypotension was observed in 7 and urinary incontinence or retention in five. All patients except three showed gastrointestinal symptoms. Anti-ganglionic acetylcholine receptor antibodies were undetectable. All but two patients received immune-modulating therapy. Immuno-modulating therapy was effective in three patients with AAG and two patients with autonomic neuropathy, but ineffective in the others. Five patients died, of either the neurological irAE (n = 3) or cancer (n = 2). The pharmacovigilance analyses using FAERS showed that ipilimumab monotherapy and the combination of nivolumab and ipilimumab constituted significant risks for developing dysautonomia, consistent with the review of literature. CONCLUSION: ICIs can cause dysautonomia including AAG, and autonomic neuropathy is a neurological irAE.

Severe treatment-refractory antibody positive autoimmune autonomic ganglionopathy after mRNA COVID19 vaccination.

BACKGROUND: COVID-19 vaccine-associated peripheral and central neuroimmunological disorders have been well described. We present the case of a 56 year old male who developed α3-ganglionic AChR antibody positive Autoimmune Autonomic Ganglionopathy (AAG) after completion of a two-dose course of mRNA (Comirnaty) vaccination for COVID19. RESULTS: A previously hypertensive 56 year old male presented with the subacute onset of severe constipation, urinary retention, erectile dysfunction, sudomotor failure, sicca symptoms, non-reactive pupils and severe orthostatic hypotension shortly after receiving the second dose of an mRNA vaccine against COVID19. Autonomic testing revealed severe cardiovagal, adrenergic and sudomotor impairment, and tonic 'half-mast' pupils with evidence of sympathetic and parasympathetic denervation. Pathological α3-ganglionic ACHR antibodies were positive in serum as detected by a new flow cytometric immunomodulation assay. Malignancy was excluded. The patient was diagnosed with severe, treatment-refractory acute AAG. CONCLUSIONS: While autonomic dysfunction has been previously reported post-COVID19 vaccination, to our knowledge this is the first reported case of antibody-positive AAG in this setting. The severity of this case is in marked contrast to the existing literature on idiopathic antibody-positive autoimmune pandysautonomia.

Evaluation of commercially available antibodies and fluorescent conotoxins for the detection of surface ganglionic acetylcholine receptor on the neuroblastoma cell line, IMR-32 by flow cytometry.

Commercially available antibodies that bind to the human muscle acetylcholine receptor (ACHR) have been validated previously for flow cytometric use (Keefe et al., 2009; Leite et al., 2008; Lozier et al., 2015). Despite a multitude of commercially available antibodies to other nicotinic ACHRs, validation in a wide variety of immunoassay formats is lacking; when studied, a large proportion of these antibodies have been deemed not fit for most research purposes (Garg and Loring, 2017). We have recently described a flow cytometric immunomodulation assay for the diagnosis of Autoimmune Autonomic Ganglionopathy (AAG) (Urriola et al., 2021) that utilises the monoclonal antibody mab35(Urriola et al., 2021) which is specific for ganglionic ACHR (gnACHR) that contain α3 subunits (Vernino et al., 1998). Other fluorescent ligands for α3-gnACHR have not been validated for flow cytometric use. We investigated 7 commercially sourced antibodies and 3 synthetic fluorescent novel conotoxins purported to specifically bind to the extracellular domains of the gnACHR, and compared the results to staining by mab35, using flow cytometry with the neuroblastoma cell line IMR-32. We also evaluated the degree of non-specific binding by depleting the cell membrane of the relevant acetylcholine receptor with a pre-incubation step involving the serum from a patient with Autoimmune Autonomic Ganglionopathy containing pathogenic antibodies to the ganglionic acetylcholine receptor. None of the assessed conotoxins, and only one antibody (mab35) was found to perform adequately in flow cytometric staining of the native ganglionic acetylcholine receptor.

A Flow Cytometric Assay to Detect Functional Ganglionic Acetylcholine Receptor Antibodies by Immunomodulation in Autoimmune Autonomic Ganglionopathy.

Autoimmune Autonomic Ganglionopathy (AAG) is an uncommon immune-mediated neurological disease that results in failure of autonomic function and is associated with autoantibodies directed against the ganglionic acetylcholine receptor (gnACHR). The antibodies are routinely detected by immunoprecipitation assays, such as radioimmunoassays (RIA), although these assays do not detect all patients with AAG and may yield false positive results. Autoantibodies against the gnACHR exert pathology by receptor modulation. Flow cytometric analysis is able to determine if this has occurred, in contrast to the assays in current use that rely on immunoprecipitation. Here, we describe the first high-throughput, non-radioactive flow cytometric assay to determine autoantibody mediated gnACHR immunomodulation. Previously identified gnACHR antibody seronegative and seropositive sera samples (RIA confirmed) were blinded and obtained from the Oxford Neuroimmunology group along with samples collected locally from patients with or without AAG. All samples were assessed for the ability to cause gnACHR immunomodulation utilizing the prototypical gnACHR expressing cell line, IMR-32. Decision limits were calculated from healthy controls, and Receiver Operating Characteristic (ROC) curves were constructed after unblinding all samples. One hundred and ninety serum samples were analyzed; all 182 expected negative samples (from healthy controls, autonomic disorders not thought to be AAG, other neurological disorders without autonomic dysfunction and patients with Systemic Lupus Erythematosus) were negative for immunomodulation (<18%), as were the RIA negative AAG and unconfirmed AAG samples. All RIA positive samples displayed significant immunomodulation. There were no false positive or negative samples. There was perfect qualitative concordance as compared to RIA, with an Area Under ROC of 1. Detection of Immunomodulation by flow cytometry for the identification of gnACHR autoantibodies offers excellent concordance with the gnACHR antibody RIA, and overcomes many of the shortcomings of immunoprecipitation assays by directly measuring the pathological effects of these autoantibodies at the cellular level. Further work is needed to determine the correlation between the degree of immunomodulation and disease severity.

Autoimmune gastrointestinal dysmotility: the interface between clinical immunology and neurogastroenterology.

Autoimmune gastrointestinal dysmotility (AGID), an idiopathic or paraneoplastic phenomenon, is a clinical form of limited autoimmune dysautonomia. The symptoms of AGID and gastrointestinal manifestations in patients with autoimmune rheumatic diseases are overlapping. Antineuronal autoantibodies are often detected in patients with AGID. Autoantibodies play a key role in GI dysmotility; however, whether they cause neuronal destruction is unknown. Hence, the connection between the presence of these autoantibodies and the specific interference in synaptic transmission in the plexus ganglia of the enteric nervous system has to be determined. The treatment options for AGID are not well-defined. However, theoretically, immunomodulatory therapies have been shown to be effective and are therefore used as the first line of treatment. Nonetheless, diverse combined immunomodulatory therapies should be considered for intractable cases of AGID. We recommend comprehensive autoimmune evaluation and cancer screening for clinical diagnosis of AGID. Univocal diagnostic criteria, treatment protocols, and outcome definitions for AGID are required for prompt diagnosis and treatment and appropriate management of immunotherapy, which will circumvent the need for surgeries and improve patient outcome. In conclusion, AGID, a disease at the interface of clinical immunology and neurogastroenterology, requires further investigations and warrants cooperation among specialists, especially clinical immunologists, gastroenterologists, and neurologists.

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.

[Autoimmune autonomic ganglionopathy].

Autoimmune autonomic ganglionopathy (AAG) is an acquired immune-mediated disorder of widespread autonomic failure. Approximately half of the patients with AAG have the autoantibodies against the neuronal nicotinic acetylcholine receptor (AChR) in autonomic ganglia. These ganglionic AChR antibodies have the potential to mediate the synaptic transmission in sympathetic, parasympathetic, and enteric ganglia. Therefore, seropositive AAG patients exhibit various autonomic symptoms. Extra-autonomic manifestations (coexistence with brain involvement, sensory disturbance, endocrine disorders, autoimmune diseases and tumors) are present in many patients with AAG. The nicotinic AChRs comprise a family of abundantly expressed ligand-gated cation channels found throughout the central and peripheral nervous systems. Moreover, limited manifestations of autoimmune dysautonomia including autoimmune gastrointestinal dysmotility are newly recognized clinical entity. Although combined immunomodulatory therapy is beneficial for almost all patients with AAG, several case reports of some AAG patients with small benefit exist. This review focuses on the recent progress in the clinical approaches of AAG and its related disorders involving the role of autoantibodies and clinical practice.

Autoimmune autonomic neuropathies and ganglionopathies: epidemiology, pathophysiology, and therapeutic advances.

Autonomic disorders can be the result of autoimmunity. The classic, well-characterized example is autoimmune autonomic ganglionopathy (AAG), in which antibodies against the ganglionic nicotinic acetylcholine receptor impair autonomic transmission, causing autonomic failure, which responds to immunotherapy. However, a number of other autoimmune disorders cause autonomic failure through a variety of mechanisms. In this article, we review autoimmune disorders causing impairment of the peripheral autonomic nervous system (ganglia and nerves), including AAG, other autoimmune autonomic neuropathies, paraneoplastic autonomic neuropathies, and neuromuscular and rheumatologic diseases with autonomic symptomatology. Awareness of primary autoimmune autonomic disorders and the autonomic manifestations of other autoimmune diseases promotes timely diagnosis and appropriate management, including supportive care for unpleasant or dangerous autonomic dysfunction, a search for underlying malignancy when indicated, and the use of immunotherapy when appropriate. A better understanding of the underlying pathophysiology aids in the judicious use and selection of immunotherapy.

[The interface between the immune system and autonomic nervous system].

  The nervous system and the immune system are two major systems in human body. Although it was revealed these two systems correlated, the control of immune cell dynamics by the nervous system has come to draw a lot of attention at the present time. Recent advances in basic and preclinical science reveal that reflex neural circuits inhibit the production of cytokines and inflammation in several animal models. One well-characterized cytokine-inhibiting mechanism, termed the "inflammatory reflex", is dependent upon vagus nerve stimulation that inhibits cytokine production and attenuates the inflammation. And the mechanism for controlling lymphocyte trafficking becomes clear, and molecular basis of immune regulation by the nervous system was reported. On the other hand, the nervous system is protected from the invasion of harmful agents by the barrier. However, there are neuroimmunological disorders, which is associated with autoimmunity, tumor immunity, and infection immunity. Autoimmune autonomic ganglionopathy (AAG) is an acquired immune-mediated disorder that leads to widespread autonomic manifestations, in which autoantibodies to ganglionic nicotinic acetylcholine receptors play a central role. Previously, we elucidated the prevalence of extra-autonomic manifestations in patients with AAG. It is necessary to establish the new systems for the detection of autoantibodies to other subunits of acetylcholine receptor.

Multiple Myeloma Presenting with Autoimmune Autonomic Ganglionopathy.

Autoimmune autonomic ganglionopathy is an autonomic disorder that occurs as a symptom of paraneoplastic neurological syndrome. To date, there have been no reports on multiple myeloma with autoimmune autonomic ganglionopathy. A 37-year-old Japanese woman suffered from orthostatic hypotension was diagnosed with multiple myeloma (IgG kappa type), and a serological examination revealed the presence of anti-ganglionic nicotinic acetylcholine receptor (anti-gAChR) antibodies. She was treated for multiple myeloma, as a result, the autonomic disturbance improved and her anti-gAChR antibody titer decreased to undetectable levels, despite the fact that she only achieved a partial remission of multiple myeloma. Treatment for multiple myeloma may improve autoimmune autonomic ganglionopathy.

A case of seropositive autoimmune autonomic ganglionopathy with diffuse esophageal spasm.

Autoimmune autonomic ganglionopathy (AAG) is an immune-mediated disorder that leads to various autonomic failures associated with anti-ganglionic acetylcholine receptor antibodies (anti-gAChR-Abs). Diffuse esophageal spasm (DES) is an uncommon esophageal motility disorder. We herein report the case of a 68-year-old woman with DES as a partial symptom of AAG. She presented with chronic esophageal transit failure, constipation, and numbness of the hands and feet, Adie's pupil, thermal hypoalgesia, and decreased deep tendon reflexes. Right sural nerve biopsy showed significantly decreased numbers of small myelinated fibers. Barium swallowing X-ray showed repetitive simultaneous contractions indicating DES in the esophagus. Gastrointestinal endoscopy and CT image showed a dilated esophageal lumen and liquid effusion. Simultaneously, serum anti-gAChR-α3-Ab indicating AAG was detected. After pulse intravenous methylprednisolone (IVMP) and intravenous immunoglobulin therapy (IVIg), the bolus progression and liquid effusion improved, suggesting that DES is an important gastrointestinal symptom of AAG.

Autoimmune autonomic ganglionopathy manifesting as acute-onset orthostatic hypotension in a patient undergoing peritoneal dialysis.

Orthostatic hypotension is an important complication in the management of patients receiving dialysis therapy. As for the orthostatic hypotension caused by decreased peripheral artery resistance, diabetic neuropathy and amyloidosis are the two main causes of hypotension in dialysis patients. However, some patients develop orthostatic hypotension that is caused by dysfunction of the autonomic nervous system, not by diabetic or amyloidosis-related neuropathy. We herein present a case of a 56-year-old man with a 17-year history of peritoneal dialysis therapy, who developed acute-onset orthostatic hypotension accompanied by hypohidrosis and erectile dysfunction. Because serum autoantibodies to ganglionic nicotinic acetylcholine receptor were detected, he was diagnosed with autoimmune autonomic ganglionopathy (AAG). He was treated with high-dose immunoglobulin therapy (0.6 g per kg of body weight per day) for 5 consecutive days, which resulted in a gradual improvement in dizziness. Two months after the onset of AAG, he could discontinue vasopressors (fludrocortisone acetate and midodrine hydrochloride) and continued maintenance dialysis therapy without the use of vasopressors. This case indicates that physicians should consider autonomic neuropathy including AAG as a differential diagnosis when they encounter dialysis patients with orthostatic hypotension.

Rituximab-based therapy and long-term control of autoimmune autonomic ganglionopathy.

We present a patient with autoimmune autonomic ganglionopathy (AAG) who had persistently positive ganglionic nicotinic acetylcholine receptor antibody levels despite immunosuppressive therapy. Rituximab-based therapy for an incidental lymphoma was associated with prolonged symptomatic and serological control of AAG.

Clinical experience of seropositive ganglionic acetylcholine receptor antibody in a tertiary neurology referral center.

INTRODUCTION: Antibody against the acetylcholine receptor of autonomic ganglia (gAChR-Ab) is implicated in the pathogenesis of autoimmune autonomic ganglionopathy (AAG) and several other disorders. METHODS: This study was a retrospective evaluation of 95 patients positive for gAChR-Ab. RESULTS: Twenty-one (22%) patients had AAG, with a greater median gAChR-Ab level (0.21 nmol/L) and higher percentage (57%) of antibody levels >0.20 nmol/L when compared with the remaining 74 patients without autonomic manifestations (non-AAG group, 0.10 nmol/L and 15%, respectively). Only 2 new cases of malignancy were diagnosed after gAChR-Ab detection. The non-AAG group was associated with high frequencies of neurological and non-neurological autoimmunity, but also included 23 (31%) patients with mostly degenerative disorders. CONCLUSION: Detection of gAChR-Ab, especially at a higher level, is helpful for the diagnosis of AAG in patients with corresponding autonomic symptoms. However, its value is limited for predicting cancer risk and for diagnosis and management of patients without autonomic symptoms.