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Background: Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis has been recently reported as autoimmune/paraneoplastic encephalitis, affecting mostly young females., Objective: To describe opsoclonus-myoclonus syndrome in association with anti-NMDAR antibodies., Design: Case report., Setting: Geneva University Hospital. Patient A 23-year-old woman with opsoclonus-myoclonus syndrome., Results: Two weeks after an episode of gastroenteritis, the patient developed symptoms of depression associated with psychomotor slowing, progressive gait instability, and opsoclonus-myoclonus. Cerebrospinal fluid examination showed mild lymphocytic pleocytosis and intrathecal IgG synthesis with oligoclonal bands. The patient's condition worsened rapidly to an akinetic mutism, followed by a period of agitation, delirium, and hallucinations. These gradually subsided; however, a frontal behavior and executive dysfunction persisted 5 months after symptom presentation. No tumor was found. Anti-NMDAR antibodies were found in the cerebrospinal fluid., Conclusions: Opsoclonus-myoclonus may occur in patients with anti-NMDAR encephalitis. Prompt diagnosis of this disorder is important because after tumor removal and immunomodulatory therapies it has a relatively good prognosis.

Background: Rapidly progressive dementia has a variety of causes, including Creutzfeldt-Jakob disease (CJD) and neuronal voltage-gated potassium channel (VGKC) autoantibody-associated encephalopathy., Objective: To describe patients thought initially to have CJD but found subsequently to have immunotherapy-responsive VGKC autoimmunity., Design: Observational, prospective case series., Setting: Department of Neurology, Mayo Clinic, and the Memory and Aging Center, University of California, San Francisco. Patients A clinical serologic cohort of 15 patients referred for paraneoplastic autoantibody evaluation. Seven patients were evaluated clinically by at least one of us. Clinical information for the remaining patients was obtained by physician interview or medical record review., Main Outcome Measures: Clinical features, magnetic resonance imaging abnormalities, electroencephalographic patterns, cerebrospinal fluid analyses, and responses to immunomodulatory therapy., Results: All the patients presented subacutely with neurologic manifestations, including rapidly progressive dementia, myoclonus, extrapyramidal dysfunction, visual hallucinations, psychiatric disturbance, and seizures; most (60%) satisfied World Health Organization diagnostic criteria for CJD. Magnetic resonance imaging abnormalities included cerebral cortical diffusion-weighted imaging hyperintensities. Electroencephalographic abnormalities included diffuse slowing, frontal intermittent rhythmic delta activity, and focal epileptogenic activity but not periodic sharp wave complexes. Cerebrospinal fluid 14-3-3 protein or neuron-specific enolase levels were elevated in 5 of 8 patients. Hyponatremia was common (60%). Neoplasia was confirmed histologically in 5 patients (33%) and was suspected in another 5. Most patients' conditions (92%) improved after immunomodulatory therapy., Conclusions: Clinical, radiologic, electrophysiologic, and laboratory findings in VGKC autoantibody-associated encephalopathy may be confused with those of CJD. Serologic evaluation for markers of neurologic autoimmunity, including VGKC autoantibodies, may be warranted in suspected CJD cases.

Background: The neuromyelitis optica IgG autoantibody (NMO-IgG) is a validated biomarker for NMO and an emerging spectrum of inflammatory central nervous system-demyelinating disorders. Its antigen is the astrocytic water channel aquaporin-4; NMO-IgG has not been described in a cancer context., Objectives: To report (1) neurologic and oncologic correlates for patients incidentally identified as NMO-IgG seropositive in a blinded evaluation for paraneoplastic autoantibodies and (2) the frequency of cancer in NMO-IgG-seropositive patients., Design: Observational, retrospective case series., Setting: Neuroimmunology Laboratory and Neurology Clinical Practice, Mayo Clinic College of Medicine., Patients and Methods: From 1998 to 2007, we detected NMO-IgG in 2 patient groups: (1) 31 patients (88% female) identified incidentally among 180 000 patients evaluated for paraneoplastic autoantibodies and (2) 141 patients identified through physician-requested serological evaluation for a suspected NMO-spectrum disorder., Results: In the first group, clinical information was available for 28 patients (90%). An NMO-spectrum disorder was diagnosed in 26 patients (93%), of whom 6 had a neoplasm (5 carcinomas [2 breast, 1 lung, 1 thymic, and 1 uterine cervical] and 1 B-cell lymphoma) and 1 had monoclonal gammopathy. In 4 patients, NMO-related symptoms followed neoplasia detection (median, 14 [range 3-18] months), and in 2 patients, symptoms preceded neoplasia detection (by 5 and 3 months). Two patients had carcinoma (1 breast and 1 lung) without neurological evidence of an NMO-spectrum disorder. In the second group, neoplasms were recorded in 7 seropositive patients (5.0%) with a clinically diagnosed NMO-spectrum disorder: 3 carcinomas (all breast), 1 thyroid Hürthle cell, 1 carcinoid, 1 pituitary somatotropinoma, and 1 B-cell lymphoma. An eighth patient had monoclonal gammopathy., Conclusions: Aquaporin-4-specific IgG in some cases of NMO may reflect a paraneoplastic immune response. The clinical utility of this autoantibody as a cancer marker warrants prospective investigation.

Autoantibodies against glutamate receptors, first reported in Rasmussen encephalitis, have been observed in other focal epilepsies, central nervous system ischemic infarcts, transient ischemic attacks, sporadic olivopontocerebellar atrophy, systemic lupus erythematosus, and paraneoplastic encephalopathies. The detection of glutamate receptor autoantibodies is not useful in the evaluation of Rasmussen encephalitis but may be a biomarker for brain ischemia, and it is helpful in diagnosing certain paraneoplastic encephalopathies. Passive transfer of glutamate receptor autoantibodies from patients with systemic lupus erythematosus or paraneoplastic encephalopathy suggests that glutamate receptor autoantibodies can actively contribute to neurologic dysfunction.

Objective: To describe a movement disorder characterized by ocular flutter, trunk ataxia, and mild generalized myoclonus associated with anti-GQ1b antibodies., Design: Case report., Setting: University hospital., Patient: A 37-year-old woman presented with rapid, conjugated, and periodic oscillations of the eyes with a strict preponderance for the horizontal plane (ocular flutter); trunk ataxia; and occasional arrhythmic muscle jerks (myoclonus) most pronounced at the neck., Results: Brain magnetic resonance imaging results were normal. Cerebrospinal fluid examination revealed mild lymphocytic pleocytosis. Results of extensive serological tests on viral, bacterial, and fungal infections from blood and cerebrospinal fluid samples were unremarkable. Results of screening examinations for neoplasms and paraneoplastic antibodies, including whole-body fludeoxyglucose F18 positron emission tomography, were normal. Positive titers of IgG and IgM anti-GQ1b antibodies were found., Conclusions: This is the first description of an association between the clinical syndrome of ocular flutter, mild stimulus sensitive myoclonus, and trunk ataxia and anti-GQ1b antibodies. The association with ganglioside antibodies lends further support to the notion of an autoimmune-associated pathology of the syndrome.

Background: Autoimmune autonomic ganglionopathy is a disorder defined by antibodies to the nicotinic acetylcholine receptor of the autonomic ganglia. Patients present with symptoms of autonomic failure, including syncope, orthostatic hypotension, bowel and bladder hypomotility, pupillary dysfunction, and dry mouth and eyes. Symptomatic and immunomodulatory therapy has provided limited clinical benefit in small uncontrolled studies., Objective: To investigate the effects of combined immunosuppressive therapy and plasmapheresis in autoimmune autonomic ganglionopathy., Design: Prospective case series., Setting: Academic medical center., Patients: Three patients with autoimmune autonomic ganglionopathy who had a limited response to symptomatic therapy, such as midodrine, fludrocortisone, vasopressin, and erythropoietin. Additional treatment with plasmapheresis alone and intravenous immunoglobulin alone provided no additional clinical benefit. Patients underwent 6 months of treatment with prednisone and mycophenolate mofetil followed by 5 cycles of plasma exchange., Results: Immunosuppressive therapy (prednisone and mycophenolate mofetil) combined with plasmapheresis resulted in substantial improvements in bowel control, pupillary function, dry mouth, and dry eyes. Mean (SD) blood pressure during immunosuppressive therapy was 162/83 (16/12) mm Hg supine and 76/45 (22/11) mm Hg standing (3 minutes). After 5 cycles of plasmapheresis, mean blood pressure was 132/82 (7/4) mm Hg supine and 127/81 (5/1) mm Hg standing (3 minutes; P < .01). Mean antibody level was 7.92 nmol/L on combined immunosuppressive therapy alone and dropped to 0.5 nmol/L after plasmapheresis., Conclusions: In patients with autoimmune autonomic ganglionopathy, combining immunosuppressive medications prednisone and mycophenolate mofetil with plasmapheresis provides substantial and sustained clinical improvement that was not seen using either treatment alone. Multi-agent immunomodulatory therapies may be necessary to satisfactorily treat this immune-mediated disorder.

Background: A possible role of autoimmunity in Alzheimer disease pathogenesis has recently attracted increasing attention. Vaccination with amyloid-beta peptide was reported to cause marked reduction in amyloid deposition, but it also induced encephalitis. Not much is known regarding neurofibrillary tangle-related autoimmune effects., Objective: To use the main component of tangles-microtubule-associated tau protein-to test the feasibility of active induction of a neuroautoimmune disorder in mice., Design: Prospective, randomized controlled animal study., Setting: University medical center research laboratory. Subjects Female C57BL/6 mice., Interventions: Inoculation with recombinant human tau protein emulsified in complete Freund adjuvant and with pertussis toxin., Main Outcome Measures: Clinical, immunologic, pathologic, and behavioral evaluations were performed., Results: Vaccination with tau protein induced histopathologic features of Alzheimer disease and tauopathies, indicated by the presence of neurofibrillary tangle-like structures, axonal damage, and gliosis. Also, mononuclear infiltrates without demyelination in the central nervous system, accompanied by neurologic deficits (such as a limp tail and limb paralysis), were observed. Anti-tau antibodies were detected in the serum of tau-immunized mice., Conclusions: These results provide a link between tau autoimmunity and tauopathy-like abnormalities and indicate potential dangers of using tau for immunotherapy. This experimental autoimmune tauopathy-like model is due to a pathogenic immune response against an intraneuronal antigen and is not related to myelin antigens.

Background: The clinical characteristics of autoimmune autonomic neuropathy are only partially defined. More than 50% of patients with high levels of ganglionic acetylcholine receptor (AChR) autoantibodies have a combination of sicca complex (marked dry eyes and dry mouth), abnormal pupillary light response, upper gastrointestinal tract symptoms, and neurogenic bladder., Objective: To compare patients with idiopathic autonomic neuropathy who were seropositive (n = 19) and seronegative (n = 87) for ganglionic AChR antibodies., Design: Retrospective review of autonomic programmatic database., Setting: Autonomic Disorders Program Project at Mayo Clinic College of Medicine, Rochester, Minn., Patients: We evaluated a cohort of 87 patients with idiopathic autonomic neuropathy who had undergone full autonomic testing and neurological evaluation and who had a complete panel of paraneoplastic and ganglionic AChR antibodies. We compared patients seropositive (n = 19) and seronegative (n = 87) for ganglionic AChR antibodies., Results: The seropositive group had a significant overrepresentation of abnormal pupillary responses (12/18 [67%] vs 12/87 [14%]; P<.001), sicca complex (9/15 [60%] vs 11/47 [23%]; P =.01), and lower gastrointestinal tract dysautonomia (16/19 [84%] vs 48/85 [56%]; P =.02). A subacute mode of onset was more common in the seropositive group (12/19 [63%] vs 23/84 [27%]; P =.004). Results of quantitative autonomic function tests differed significantly in the 2 groups only in the cardiovagal domain. Because subacute onset was overrepresented in the seropositive group, we analyzed the data separately, controlling for temporal profile (ie, the relationship between antibody status and symptoms while controlling for rate of onset). The relationships between antibody status and clinical profile (eg, presence of sicca complex, pupillary abnormalities, and lower gastrointestinal tract symptoms) generally remained significant regardless of onset rate, indicating that the associations are not due to temporal profile., Conclusions: These observations support the concept that ganglionic AChR antibodies are diagnostically and pathophysiologically important. Patients with orthostatic hypotension and prominent cholinergic dysautonomia are most likely to be seropositive for ganglionic AChR antibody.