Isolated Optic Neuritis: Etiology, Characteristics, and Outcomes in a US Mountain West Cohort

BACKGROUND

The diagnosis and treatment of autoimmune optic neuritis (ON) has improved with the accessibility and reliability of aquaporin-4 (AQP4) and myelin oligodendrocyte glycoprotein (MOG) antibody testing, yet autoantibody-negative ON remains common. This study describes the demographic, clinical, and outcome data in patients with isolated ON across the pediatric and adult cohort.

METHODS

A retrospective chart review of University of Utah Health patients with the International Classification of Diseases (ICD) code of ICD-9 377.30 (ON unspecified), ICD-9 377.39 (other ON), or ICD-10 H46 (ON) and at least 2 ophthalmologic evaluations were conducted between February 2011 and July 2023. Only isolated cases of ON without other brain or spinal demyelinating lesions were evaluated. Differences in demographic and clinical characteristics between AQP4, MOG, and Other-ON were determined.

RESULTS

Of the 98 patients (15 children and 83 adults), 9 (9.2%) were positive for AQP4-IgG and 35 (35.7%) tested positive for MOG-IgG. Fifty-four were classified into Other-ON, of which 7 (13.0%) had recurrence or new demyelinating lesions during a median follow-up of 12.5 months-2 were ultimately diagnosed with recurrent isolated ON (RION), 1 with chronic relapsing inflammatory ON (CRION), 2 with multiple sclerosis, 1 with collapsin response-mediator protein (CRMP)-5-ON, and 1 with seronegative neuromyelitis optica spectrum disorder. Four patients were treated with long-term immunosuppressive therapy. No patients with RION or CRION had preceding infections; they had first recurrences of ON within 2 months. At presentation, AQP4-ON (75%) and MOG-ON (48.8%) had more severe vision loss (visual acuity <20/200) than Other-ON (23.2%, P = 0.01). At the 1-month follow-up, 93.0% of patients with MOG-ON and 89.3% of patients with Other-ON demonstrated a visual acuity ≥20/40, compared with only 50% of patients with AQP4-ON (P < 0.01). By the last follow-up, 37.5% of the AQP4-ON still exhibited visual acuity <20/40, including 25% who experienced severe vision loss (visual acuity <20/200). By contrast, over 95% of patients with MOG-ON and Other-ON maintained a visual acuity of ≥20/40. In our cohort, over a quarter of pediatric cases presented with simultaneous bilateral ON, 40% had a preceding infection, and 44.4% initially presented with a visual acuity <20/200. Two pediatric cases had recurrence, and both were MOG-ON. By their last follow-up, all pediatric cases had achieved a visual acuity of 20/40 or better. In addition, pediatric cases were more likely to exhibit disc edema compared with adult cases (100% vs 64%, P < 0.01).

CONCLUSIONS

Despite recent advances in identification and availability of testing for AQP4-IgG and MOG-IgG, over half of patients who presented with isolated ON remained with an "idiopathic" diagnostic label. As more than 1 in 10 patients with AQP4-IgG and MOG-IgG negative ON experienced recurrence or develop new demyelinating lesions, clinicians should provide anticipatory guidance and closely monitor for potential long-term outcomes. In addition, it is crucial to re-evaluate the diagnosis in cases of poor recovery, ON recurrence, and the emergence of new neurological symptoms, as ON can often be the initial presentation of other conditions.

Vasculitis in the Central Nervous System: Etiology, Characteristics, and Outcomes in a Large Single-Center Cohort

Background and Purpose

For the management of central nervous system (CNS) vasculitis, it is crucial to differentiate between primary and secondary CNS vasculitis and to understand the respective etiologies. We assessed the etiology, characteristics, and outcomes of patients with CNS vasculitis.

Methods

A single-center retrospective chart review was conducted at the University of Utah, Department of Neurology, between February 2011 and October 2022.

Results

The median age of the 44 included patients at diagnosis was 54 years; 25.0% were men. Compared to primary CNS vasculitis, secondary CNS vasculitis exhibits higher fever incidence (observed in infectious and connective tissue disorder [CTD]-associated vasculitis), low glucose levels (mostly in infectious vasculitis) and unique cerebrospinal fluid oligoclonal bands (observed in infectious and CTD-associated vasculitis). Patients with inflammatory cerebral amyloid angiopathy (CAA) were older and more commonly had microhemorrhage than primary angiitis of the CNS (PACNS). All patients with CTD-associated vasculitis had a known history of CTD at presentation. Brain biopsies were performed on 10 of 17 PACNS patients and 4 of 8 inflammatory CAA patients, confirming vasculitis in 7 and 4 patients, respectively. Intravenous methylprednisolone was the predominant induction therapy (63.6%), and cyclophosphamide was the most used adjunctive therapy. Cyclophosphamide, rituximab, azathioprine, and mycophenolate mofetil were utilized as maintenance therapy, often with concurrent prednisone. Patients with inflammatory CAA had a higher tendency for relapse rates than PACNS.

Conclusions

This study highlights the variations in patients' characteristics, symptoms, and treatment for CNS vasculitis. Understanding these differences can lead to more efficient diagnostic and management strategies.

Cardiac Involvement in Neurosarcoidosis: A Single-Center Investigation

BACKGROUND AND OBJECTIVES

Sarcoidosis is a multisystem inflammatory granulomatous disease. Among systemic sarcoidosis manifestations, cardiac or nervous system involvement can result in significant morbidity and mortality. We describe the overlapping incidence of cardiac sarcoidosis (CS) within a neurosarcoidosis (NS) cohort and determine the frequency of other nonsarcoid cardiac diseases in these patients.

METHODS

We performed a retrospective chart review of patients evaluated at the University of Utah from 2010 to 2022. Patients were included if they had (1) at least one instance of a diagnostic code for sarcoidosis in their medical record-International Classification of Diseases (ICD) 9 code 135 or ICD 10 code D86; (2) at least one outpatient visit in the Neurology Department within the University of Utah electronic health record with a diagnosis of definite, probable, or possible NS based on 2018 consensus criteria; (3) at least one outpatient visit in the Cardiology Department within the University of Utah electronic health record; and (4) ECG available in their medical record for review. Of 64 definite, probable, or possible patients with NS in the University of Utah cohort, 52 met our inclusion criteria and were included in this study.

RESULTS

Of 52 patients with NS who met our inclusion criteria, 65.38% were female, with an average age of 60.9 years (range 38-84). More than half (58%) were obese (BMI ≥ 30). CS was diagnosed in 6 patients with NS (12%). Symptoms suggestive of possible cardiac dysfunction included lower extremity edema (50%), palpitations (46%), chest pain (44%), and shortness of breath (27%). ECG abnormalities included nonspecific T-wave change (40%) and right bundle branch block (17%). Three patients experienced ventricular tachycardia: sustained in one patient and nonsustained in 2 patients. Cardiac MRI was performed in 17 patients (32.7%) and in 3 patients (17.6%), which revealed diffuse myocardial enhancement suggesting CS.

DISCUSSION

In this cohort, 12% of patients with NS also had confirmed CS. In addition, these patients had a high burden of cardiovascular disease not directly attributed to sarcoidosis. Our data suggest that patients with NS require comprehensive cardiac evaluation. Future studies are needed to clarify the extent of the direct contribution of granulomatous inflammation on the cardiovascular system from the indirect contribution of treatments such as glucocorticoids that lead to increased risk of cardiovascular disease in sarcoidosis.

PNMA2 forms immunogenic non-enveloped virus-like capsids associated with paraneoplastic neurological syndrome

The paraneoplastic Ma antigen (PNMA) proteins are associated with cancer-induced paraneoplastic syndromes that present with an autoimmune response and neurological symptoms. Why PNMA proteins are associated with this severe autoimmune disease is unclear. PNMA genes are predominantly expressed in the central nervous system and are ectopically expressed in some tumors. We show that PNMA2, which has been co-opted from a Ty3 retrotransposon, encodes a protein that is released from cells as non-enveloped virus-like capsids. Recombinant PNMA2 capsids injected into mice induce autoantibodies that preferentially bind external "spike" PNMA2 capsid epitopes, whereas a capsid-assembly-defective PNMA2 protein is not immunogenic. PNMA2 autoantibodies in cerebrospinal fluid of patients with anti-Ma2 paraneoplastic disease show similar preferential binding to spike capsid epitopes. PNMA2 capsid-injected mice develop learning and memory deficits. These observations suggest that PNMA2 capsids act as an extracellular antigen, capable of generating an autoimmune response that results in neurological deficits.

Epidemiology of paraneoplastic neurologic syndromes

Paraneoplastic neurologic syndromes (PNS), initially depicted as seemingly cryptic remote manifestations of malignancy, were first described clinically in the early 20th century, with pathophysiologic correlates becoming better elucidated in the latter half of the century. There remain many questions not only about the pathophysiology but also regarding the epidemiology of these conditions. The continuous discovery of novel autoantigens and related neurologic disease has broadened the association in classical PNS to include conditions such as paraneoplastic cerebellar degeneration. It has also brought into focus several other neurologic syndromes with a putative neoplastic association. These conditions are overall rare, making it difficult to capture large numbers of patients to study, and raising the question of whether incidence is increasing over time or improved identification is driving the increased numbers of cases. With the rise and increasing use of immunotherapy for cancer treatment, the incidence of these conditions is additionally expected to rise and may present with various clinical symptoms. As we enter an era of clinical trial intervention in these conditions, much work is needed to capture more granular data on population groups defined by socioeconomic characteristics such as age, ethnicity, economic resources, and gender to optimize care and clinical trial planning.

Pearls & Oy-sters: ATX-FGF14 Mimicking Autoimmune Pathology

ATX-FGF14 (formerly spinocerebellar ataxia 27, OMIM #193003) is an autosomal dominant condition caused by a pathogenic variant in the fibroblast growth factor 14 (FGF14, OMIM #601515) gene located on chromosome 13. The phenotypic expression can vary in patients with the same genotype, often delaying diagnosis, especially in probands without known affected relatives and/or with limited available family history. We describe 2 cases of ATX-FGF14 in 1 family with a focus on the importance of differentiating episodic manifestations of neurogenetic conditions from inflammatory/autoimmune neurologic conditions. A 68-year-old male patient (case 1) presented with episodic dysarthria, dizziness, imbalance, and encephalopathy, creating suspicion for a possible autoimmune etiology. At the first evaluation, the patient reported no significant family history. Four years later, on revisiting the family history, he noted that his 49-year-old niece (case 2) had also developed neurologic symptoms of an unclear etiology. On evaluation, she had tremor and ataxia. Both patients also had coexistent evidence of systemic autoimmunity that likely contributed to the initial suspicion of neurologic autoimmunity, and neither had cerebellar or brainstem volume loss. Ultimately, their genetic testing revealed a pathogenic structural variant in the FGF14 gene, consistent with ATX-FGF14. These 2 cases highlight the importance of a detailed interval family history at each visit, especially in undiagnosed adult patients, as well as the importance of objectively analyzing the impact of immunotherapy diagnostic treatment trials to avoid unnecessary immunomodulatory medications.

High level of agreement in a fixed vs. live cell-based assay for antibodies to myelin oligodendrocyte glycoprotein in a real-world clinical laboratory setting

Introduction

As recognition of myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease becomes more widespread, the importance of appropriately ordering and interpreting diagnostic testing for this antibody increases. Several assays are commercially available for MOG testing, and based on a few small studies with very few discrepant results, some have suggested that live cell-based assays (CBA) are superior to fixed CBA for clinical MOG antibody testing. We aimed to determine the real-world agreement between a fixed and live CBA for MOG using two of the most commonly available commercial testing platforms.

Methods

We compared paired clinical samples tested at two national clinical reference laboratories and determined the real-world agreement between the fixed CBA and live CBA.

Results

Of 322 paired samples tested on both platforms, 53 were positive and 246 were negative by both methodologies (agreement 92.9%, Cohen's kappa 0.78, [0.69-0.86]). Spearman correlation coefficient was 0.80 (p < 0.0001). Of the discrepant results, only 1 of 14 results positive by the live CBA had a titer greater than 1:100, and only 1 of 9 results positive by the fixed CBA had a titer of greater than 1:80. Lower titers on the fixed CBA correlate to higher titers on the live CBA.

Conclusion

Overall, there is excellent agreement between fixed and live CBA for MOG antibody testing in a real-world clinical laboratory setting. Clinicians should be aware of which method they use to assess any given patient, as titers are comparable, but not identical between the assays.

Neurologic involvement in seronegative primary Sjögren's syndrome with positive minor salivary gland biopsy: a single-center experience

Objective

To assess the demographics, neurologic manifestations, comorbidities, and treatment of patients with seronegative primary Sjögren's syndrome (pSS).

Patients and methods

We conducted a retrospective chart review on patients with seronegative pSS evaluated by a neurologist at the University of Utah Health between January 2010 and October 2018. The diagnosis was based on characteristic symptoms, positive minor salivary gland biopsy according to the American-European Consensus Group 2002 criteria, and seronegative antibody status.

Results

Of 45 patients who met the study criteria, 42 (93.3%) were Caucasian, and 38 (84.4%) were female. The patients' mean age at diagnosis was 47.8 ± 12.6 (range 13-71) years. Paresthesia, numbness and dizziness, and headache were noted in 40 (88.9%), 39 (86.7%), and 36 patients (80.0%), respectively. Thirty-four patients underwent brain magnetic resonance imaging. Of these, 18 (52.9%) showed scattered nonspecific periventricular and subcortical cerebral white matter T2/fluid-attenuated inversion recovery hyperintense foci. Twenty-nine patients (64.4%) presented to the neurology clinic prior to pSS diagnosis, and the median delay in diagnosis from the first neurology clinic visit was 5 (interquartile ranges 2.0-20.5) months. Migraine and depression were the most common comorbidities in 31 patients (68.9%). Thirty-six patients received at least one immunotherapy, and 39 were on at least one medication for neuropathic pain.

Conclusion

Patients often display various nonspecific neurological symptoms. Clinicians should express a high degree of skepticism regarding seronegative pSS and consider minor salivary gland biopsy to avoid delaying diagnosis, as undertreatment can affect patients' quality of life.

Neurologic Manifestations of Common Variable Immunodeficiency: Impact on Quality of Life

BACKGROUND AND OBJECTIVES

Common variable immunodeficiency is a systemic disease and not solely a disease of humoral immunity. Neurologic symptoms associated with common variable immunodeficiency are underrecognized and warrant further study. This work aimed to characterize the neurologic symptoms reported by people living with common variable immunodeficiency.

METHODS

We conducted a single academic medical center study of neurologic symptoms reported by adults previously diagnosed with common variable immunodeficiency. We used a survey of common neurologic symptoms to determine the prevalence of these symptoms in a population with common variable immunodeficiency and further assessed these patient-reported symptoms with validated questionnaires and compared symptom burden with other neurologic conditions.

RESULTS

A volunteer sample of adults (aged 18 years or older) previously diagnosed with common variable immunodeficiency at the University of Utah Clinical Immunology/Immune Deficiency Clinic who were able to read and comprehend English and willing and able to answer survey-based questions were recruited. Of 148 eligible participants identified, 80 responded and 78 completed the surveys. The mean age of respondents was 51.3 years (range 20-78 years); 73.1% female and 94.8% White. Patients with common variable immunodeficiency reported many common neurologic symptoms (mean 14.6, SD 5.9, range 1-25), with sleep issues, fatigue, and headache reported by more than 85%. Validated questionnaires addressing specific neurologic symptoms supported these results. T-scores on Neuro QoL questionnaires for sleep (mean 56.4, SD 10.4) and fatigue (mean 54.1, SD 11) were higher, indicating more dysfunction, than in the reference clinical population (p < 0.005). The Neuro QoL questionnaire for cognitive function showed a lower T-score (mean 44.8, SD 11.1) than that in the reference general population (p < 0.005), indicating worse function in this domain.

DISCUSSION

Among survey respondents, there is a marked burden of neurologic symptoms. Given the impact of neurologic symptoms on health-related quality-of-life measures, clinicians should screen patients with common variable immunodeficiency for the presence of these symptoms and offer referral to neurologists and/or symptomatic treatment when indicated. Frequently prescribed neurologic medications may also affect the immune system, and neurologists should consider screening patients for immune deficiency before prescribing them.

PNMA2 forms non-enveloped virus-like capsids that trigger paraneoplastic neurological syndrome

The paraneoplastic Ma antigen (PNMA) genes are associated with cancer-induced paraneoplastic syndromes that present with neurological symptoms and autoantibody production. How PNMA proteins trigger a severe autoimmune disease is unclear. PNMA genes are predominately expressed in the central nervous system with little known functions but are ectopically expressed in some tumors. Here, we show that PNMA2 is derived from a Ty3 retrotransposon that encodes a protein which forms virus-like capsids released from cells as non-enveloped particles. Recombinant PNMA2 capsids injected into mice induce a robust autoimmune reaction with significant generation of autoantibodies that preferentially bind external "spike" PNMA2 capsid epitopes, while capsid-assembly-defective PNMA2 protein is not immunogenic. PNMA2 autoantibodies present in cerebrospinal fluid of patients with anti-Ma2 paraneoplastic neurologic disease show similar preferential binding to PNMA2 "spike" capsid epitopes. These observations suggest that PNMA2 capsids released from tumors trigger an autoimmune response that underlies Ma2 paraneoplastic neurological syndrome.

Autoimmune Encephalitis Misdiagnosis in Adults

Importance

Autoimmune encephalitis misdiagnosis can lead to harm.

Objective

To determine the diseases misdiagnosed as autoimmune encephalitis and potential reasons for misdiagnosis.

Design, Setting, and Participants

This retrospective multicenter study took place from January 1, 2014, to December 31, 2020, at autoimmune encephalitis subspecialty outpatient clinics including Mayo Clinic (n = 44), University of Oxford (n = 18), University of Texas Southwestern (n = 18), University of California, San Francisco (n = 17), University of Washington in St Louis (n = 6), and University of Utah (n = 4). Inclusion criteria were adults (age ≥18 years) with a prior autoimmune encephalitis diagnosis at a participating center or other medical facility and a subsequent alternative diagnosis at a participating center. A total of 393 patients were referred with an autoimmune encephalitis diagnosis, and of those, 286 patients with true autoimmune encephalitis were excluded.

Main Outcomes and Measures

Data were collected on clinical features, investigations, fulfillment of autoimmune encephalitis criteria, alternative diagnoses, potential contributors to misdiagnosis, and immunotherapy adverse reactions.

Results

A total of 107 patients were misdiagnosed with autoimmune encephalitis, and 77 (72%) did not fulfill diagnostic criteria for autoimmune encephalitis. The median (IQR) age was 48 (35.5-60.5) years and 65 (61%) were female. Correct diagnoses included functional neurologic disorder (27 [25%]), neurodegenerative disease (22 [20.5%]), primary psychiatric disease (19 [18%]), cognitive deficits from comorbidities (11 [10%]), cerebral neoplasm (10 [9.5%]), and other (18 [17%]). Onset was acute/subacute in 56 (52%) or insidious (>3 months) in 51 (48%). Magnetic resonance imaging of the brain was suggestive of encephalitis in 19 of 104 patients (18%) and cerebrospinal fluid (CSF) pleocytosis occurred in 16 of 84 patients (19%). Thyroid peroxidase antibodies were elevated in 24 of 62 patients (39%). Positive neural autoantibodies were more frequent in serum than CSF (48 of 105 [46%] vs 7 of 91 [8%]) and included 1 or more of GAD65 (n = 14), voltage-gated potassium channel complex (LGI1 and CASPR2 negative) (n = 10), N-methyl-d-aspartate receptor by cell-based assay only (n = 10; 6 negative in CSF), and other (n = 18). Adverse reactions from immunotherapies occurred in 17 of 84 patients (20%). Potential contributors to misdiagnosis included overinterpretation of positive serum antibodies (53 [50%]), misinterpretation of functional/psychiatric, or nonspecific cognitive dysfunction as encephalopathy (41 [38%]).

Conclusions and Relevance

When evaluating for autoimmune encephalitis, a broad differential diagnosis should be considered and misdiagnosis occurs in many settings including at specialized centers. In this study, red flags suggesting alternative diagnoses included an insidious onset, positive nonspecific serum antibody, and failure to fulfill autoimmune encephalitis diagnostic criteria. Autoimmune encephalitis misdiagnosis leads to morbidity from unnecessary immunotherapies and delayed treatment of the correct diagnosis.

GABA-A Receptor Encephalitis After Autologous Hematopoietic Stem Cell Transplant forMultiple Myeloma

Background and Objectives

The relationship between autologous hematopoietic stem cell transplant (aHSCT) for multiple myeloma (MM) and anti-GABA_A receptor (GABA_AR) encephalitis is unknown. We aimed to describe the clinical features, diagnostic process, and outcome of 3 cases of anti-GABA_AR encephalitis in patients with a history of prior aHSCT for MM.

Methods

A case series of 3 patients. Anti-GABA_AR antibody was tested at the University of Pennsylvania Laboratory.

Results

The patients were all male, aged 52 (case 1), 61 (case 2), and 62 (case 3) years at encephalitis symptom onset. The duration between completion of aHSCT and the onset of encephalitis was 43, 18, and 9 months, respectively. All 3 patients presented with new seizures and altered cognitive function. Other symptoms included headache and visual obscurations in cases 1 and 2 and intractable vertigo and mania in case 3. Brain MRI demonstrated nonenhancing multifocal T2-weighted/fluid-attenuated inversion recovery cortical and subcortical hyperintensities in all 3 patients. Cases 2 and 3 underwent brain biopsy before initiating immunomodulatory therapy, which demonstrated nonspecific encephalitis with astrogliosis in the white matter; these 2 patients were started on immunotherapy for the treatment of anti-GABA_AR encephalitis after 22 days and 3 months, respectively, from the first presentation. Case 1 was started on empiric immunotherapy within 8 days of presentation without requiring brain biopsy, given characteristic MRI imaging. CSF analysis demonstrated the presence of anti-GABA_AR antibodies in all 3 cases. Cases 1 and 3 also tested positive for anti-GABA_AR antibodies in the serum (serum test was not performed in case 2). Cases 1 and 2 recovered to work full-time within 1 year. Case 3 reported occasional myoclonic-like movement.

Discussion

We highlight the importance of considering anti-GABA_AR encephalitis in patients with seizures, multifocal nonenhancing brain lesions, and a history of aHSCT for MM. Awareness in recovered post-aHSCT patients with MM may be crucial because prompt recognition can avoid brain biopsy and delays in treatment. The rapid initiation of immunotherapy while awaiting autoantibody results will likely improve functional outcomes.

Adrenal Crisis Presenting as Recurrent Encephalopathy Mimicking Autoimmune, Infectious Encephalitis, and Common Variable Immune Deficiency: A Case Report

INTRODUCTION

Adrenal crisis can present with life-threatening complications and mimic autoimmune or infectious encephalitis, and common variable immune deficiency (CVID). The literature regarding the neurological complications of adrenal crisis is limited and focuses on patients who present with hypotension and electrolyte abnormalities.

CASE REPORT

A 30-year-old man presented 3 times to our hospital with encephalopathy, fever, and left sided weakness with a history of multiple autoimmune diseases and prior hospitalizations for encephalopathy. During his first 2 admissions, he was normotensive and without electrolyte abnormalities. Extensive workup for infectious, paraneoplastic, seizure, metabolic, toxic, and vascular etiologies, and autoimmune encephalitis was negative. His exam returned to baseline with empiric steroid treatment, and he was discharged. He re-presented 2 months later with encephalopathy for a third admission. During this subsequent presentation, he had hyponatremia, low serum osmolality, elevated urine sodium, undetectable morning cortisol, and 21-α hydroxylase autoantibodies. A diagnosis of autoimmune adrenal insufficiency was established, he was treated with physiological doses of hydrocortisone and fludrocortisone, and improved rapidly to near baseline function. He has remained relapse-free at 4-year follow up. During all admissions, he was also found to have low immunoglobulin G levels and met criteria for CVID; however, his immunoglobin levels recovered with steroid replacement.

CONCLUSION

The reported patient demonstrated some of the neurological complications of adrenal crisis which can mimic other autoimmune conditions such as CVID. The neurologist should be aware that recurrent encephalopathy from adrenal insufficiency can occur regardless of hemodynamic or electrolyte changes on typical hospital metabolic panels.

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.

Biopsy-proven PML in an HIV-negative patient with discoid lupus: Failure to detect JC virus in CSF

We present a case of a 58-year-old man with a history of severe discoid lupus erythematosus and acute encephalopathy and incoordination. Antinuclear antibody testing was weakly positive but all other laboratory tests for systemic lupus erythematosus were negative and serum quantitative immunoglobulins and lymphocytes were normal. MRI brain showed T2/FLAIR hyperintensities within the bilateral parietal and temporal lobes with involvement of subcortical U fibers. CSF PCR was negative for varicella-zoster virus, herpes simplex, JCV and BK virus. However, JCV antibody index was elevated (3.88; reference: < 0.2). Right parietal brain biopsy was consistent with JCV infection and diagnostic of progressive multifocal leukoencephalopathy (PML). To the best of our knowledge, this is the first reported case of PML in a patient with discoid lupus without other traditional risk factors for the disease and highlights the need for clinical vigilance in this patient population.

Modern Look at Transverse Myelitis and Inflammatory Myelopathy: Epidemiology of the National Veterans Health Administration Population

BACKGROUND AND OBJECTIVES

To characterize population-level data associated with transverse myelitis (TM) within the US Veterans Health Administration (VHA).

METHODS

This retrospective review used VHA electronic medical record from 1999 to 2015. We analyzed prevalence, disease characteristics, modified Rankin Scale (mRS) scores, and mortality data in patients with TM based on the 2002 Diagnostic Criteria.

RESULTS

We identified 4,084 patients with an International Classification of Diseases (ICD) code consistent with TM and confirmed the diagnosis in 1,001 individuals (90.7% males, median age 64.2, 67.7% Caucasian, and 31.4% smokers). The point prevalence was 7.86 cases per 100,000 people. Less than half of the cohort underwent a lumbar puncture, whereas only 31.8% had a final, disease-associated TM diagnosis. The median mRS score at symptom onset was 3 (interquartile range 2-4), which remained unchanged at follow-up, although less than half (43.2%) of the patients received corticosteroids, IVIg, or plasma exchange. Approximately one-quarter of patients (24.3%) had longitudinal extensive TM, which was associated with poorer outcomes (p = 0.002). A total of 108 patients (10.8%) died during our review (94.4% males, median age 66.5%, and 70.4% Caucasian). Mortality was associated with a higher mRS score at follow-up (OR 1.94, 95% CI, 1.57-2.40) and tobacco use (OR 1.87, 95% CI, 1.17-2.99).

DISCUSSION

This national TM review highlights the relatively high prevalence of TM in a modern cohort. It also underscores the importance of a precise and thorough workup in this disabling disorder to ensure diagnostic precision and ensure optimal management for patients with TM in the future.

Consensus disease definitions for neurologic immune-related adverse events of immune checkpoint inhibitors

Expanding the US Food and Drug Administration-approved indications for immune checkpoint inhibitors in patients with cancer has resulted in therapeutic success and immune-related adverse events (irAEs). Neurologic irAEs (irAE-Ns) have an incidence of 1%-12% and a high fatality rate relative to other irAEs. Lack of standardized disease definitions and accurate phenotyping leads to syndrome misclassification and impedes development of evidence-based treatments and translational research. The objective of this study was to develop consensus guidance for an approach to irAE-Ns including disease definitions and severity grading. A working group of four neurologists drafted irAE-N consensus guidance and definitions, which were reviewed by the multidisciplinary Neuro irAE Disease Definition Panel including oncologists and irAE experts. A modified Delphi consensus process was used, with two rounds of anonymous ratings by panelists and two meetings to discuss areas of controversy. Panelists rated content for usability, appropriateness and accuracy on 9-point scales in electronic surveys and provided free text comments. Aggregated survey responses were incorporated into revised definitions. Consensus was based on numeric ratings using the RAND/University of California Los Angeles (UCLA) Appropriateness Method with prespecified definitions. 27 panelists from 15 academic medical centers voted on a total of 53 rating scales (6 general guidance, 24 central and 18 peripheral nervous system disease definition components, 3 severity criteria and 2 clinical trial adjudication statements); of these, 77% (41/53) received first round consensus. After revisions, all items received second round consensus. Consensus definitions were achieved for seven core disorders: irMeningitis, irEncephalitis, irDemyelinating disease, irVasculitis, irNeuropathy, irNeuromuscular junction disorders and irMyopathy. For each disorder, six descriptors of diagnostic components are used: disease subtype, diagnostic certainty, severity, autoantibody association, exacerbation of pre-existing disease or de novo presentation, and presence or absence of concurrent irAE(s). These disease definitions standardize irAE-N classification. Diagnostic certainty is not always directly linked to certainty to treat as an irAE-N (ie, one might treat events in the probable or possible category). Given consensus on accuracy and usability from a representative panel group, we anticipate that the definitions will be used broadly across clinical and research settings.

Autoimmune Neurology: The Need for Comprehensive Care

Autoimmune neurology is a rapidly developing specialty driven by an increasing recognition of autoimmunity as the cause for a broad set of neurologic disorders and ongoing discovery of new neural autoantibodies associated with recognizable clinical syndromes. The diversity of clinical presentations, unique pathophysiology, and the complexity of available treatments requires a dedicated multidisciplinary team to diagnose and manage patients. In this article, we focus on antibody-associated autoimmune encephalitis (AE) to illustrate broader themes applicable to the specialty. We discuss common diagnostic challenges including the utilization of clinical assessment tools along with the determination of the prognostic significance of certain autoantibodies, with a focus on implications for long-term management. A growing body of literature demonstrates the long-term cognitive, behavioral, and physical sequelae of AE. Dedicated resources are needed to effectively manage these patients. These resources may be best provided by experienced neurology clinics in partnership with other neurologic subspecialists, as well as psychiatrists, neuropsychologists, and physical medicine and rehabilitation providers.

A multi-center case series of sarcoid optic neuropathy

OBJECTIVE

The diagnosis of sarcoid optic neuropathy is time-sensitive, as delayed treatment risks irreversible vision loss. We sought to analyze its characteristics and outcomes.

METHODS

We performed a multi-center retrospective study of sarcoid optic neuropathy among 5 USA medical centers. Inclusion criteria were: 1) clinical optic neuropathy; 2) optic nerve/sheath enhancement on neuroimaging; 3) pathological confirmation of systemic or nervous system sarcoidosis.

RESULTS

Fifty-one patients were included. The median onset age of sarcoid optic neuropathy was 50 years (range, 17-70 years) and 71% were female. The median visual acuity at nadir in the most affected eye was 20/80 (range, 20/20 to no-light-perception). Thirty-four of 50 (68%) patients had radiologic evidence of other nervous system involvement and 20 (39%) patients had symptoms/signs of other cranial nerve dysfunction. Cerebrospinal fluid analysis revealed an elevated white blood cell count in 22 of 31 (71%) patients (median: 14/μL; range: 1-643/μL). Pathologic confirmation of sarcoidosis was by biopsy of systemic/pulmonary site, 34 (67%); optic nerve/sheath, 9 (18%); or other nervous system region, 8 (16%). Forty patients improved with treatment (78%), 98% receiving corticosteroids and 65% receiving steroid-sparing immunosuppressants, yet 11/46 patients (24%) had a visual acuity of 20/200 or worse at last follow-up.

CONCLUSIONS

Sarcoid optic neuropathy frequently occurs with other clinical and radiologic abnormalities caused by neurosarcoidosis and diagnostic confirmation occasionally requires optic nerve/sheath biopsy. Improvement with treatment is common but most patients have some residual visual disability. Improved recognition and a more expeditious diagnosis and treatment may spare patients from permanent vision loss.

gene.iobio: an interactive web tool for versatile, clinically-driven variant interrogation and prioritization

With increasing utilization of comprehensive genomic data to guide clinical care, anticipated to become the standard of care in many clinical settings, the practice of diagnostic medicine is undergoing a notable shift. However, the move from single-gene or panel-based genetic testing to exome and genome sequencing has not been matched by the development of tools to enable diagnosticians to interpret increasingly complex genomic findings. A new paradigm has emerged, where genome-based tests are often evaluated by a large multi-disciplinary collaborative team, typically including a diagnostic pathologist, a bioinformatician, a genetic counselor, and often a subspeciality clinician. This team-based approach calls for new computational tools to allow every member of the clinical care provider team, at varying levels of genetic knowledge and diagnostic expertise, to quickly and easily analyze and interpret complex genomic data. Here, we present gene.iobio , a real-time, intuitive and interactive web application for clinically-driven variant interrogation and prioritization. We show gene.iobio is a novel and effective approach that significantly improves upon and reimagines existing methods. In a radical departure from existing methods that present variants and genomic data in text and table formats, gene.iobio provides an interactive, intuitive and visually-driven analysis environment. We demonstrate that adoption of gene.iobio in clinical and research settings empowers clinical care providers to interact directly with patient genomic data both for establishing clinical diagnoses and informing patient care, using sophisticated genomic analyses that previously were only accessible via complex command line tools.

Neuroimmunogastroenterology: At the Interface of Neuroimmunology and Gastroenterology

The central nervous system (CNS) is an important regulator of the gastrointestinal tract, and CNS dysfunction can result in significant and disabling gastrointestinal symptom manifestation. For patients with neuroimmunologic and neuroinflammatory conditions, the recognition of gastrointestinal symptoms is under-appreciated, yet the gastrointestinal manifestations have a dramatic impact on quality of life. The current treatment strategies, often employed independently by the neurologist and gastroenterologist, raise the question of whether such patients are being treated optimally when siloed in one specialty. Neuroimmunogastroenterology lies at the borderlands of medical specialties, and there are few resources to guide neurologists in this area. Here, we provide an overview highlighting the potential mechanisms of crosstalk between immune-mediated neurological disorders and gastrointestinal dysfunction.

Neurosarcoidosis: Longitudinal experience in a single-center, academic healthcare system

OBJECTIVE

To characterize patients with neurosarcoidosis within the University of Utah healthcare system, including demographics, clinical characteristics, treatment, and long-term outcomes.

METHODS

We describe the clinical features and outcomes of patients with neurosarcoidosis within the University of Utah healthcare system (a large referral center for 10% of the continental United States by land mass). Patients were selected who met the following criteria: (1) at least one International Classification of Diseases Clinical Modification, 9th revision code 135 or International Classification of Diseases Clinical Modification, 10th revision code D86* (sarcoidosis) and (2) at least one outpatient visit with a University of Utah clinician in the Neurology Department within the University of Utah electronic health record.

RESULTS

We identified 56 patients meeting the study criteria. Thirty-five patients (63%) were women, and most patients (84%) were white. Twelve patients (22%) met the criteria for definite neurosarcoidosis, 36 patients (64%) were diagnosed with probable neurosarcoidosis, and 8 patients (14%) were diagnosed with possible neurosarcoidosis. A total of 8 medications were used for the treatment of neurosarcoidosis. Prednisone was the first-line treatment in 51 patients (91%). Infliximab was the most effective therapy, with 87% of patients remaining stable or improving on infliximab. Treatment response for methotrexate and azathioprine was mixed, and mycophenolate mofetil and rituximab were the least effective treatments in this cohort.

CONCLUSIONS

This is a comprehensive characterization of neurosarcoidosis within a single healthcare system at the University of Utah that reports long-term response to treatment and outcomes of patients with neurosarcoidosis. Our results suggest the use of infliximab as a first-line therapy for neurosarcoidosis.

Innovations in on-demand audio education

The evolution of broadcast audio has been rapidly changing over the past 10–15 years with the advent of podcasts in the early 2000s. As with other media, podcast audio has been adapted for use within medical and specifically neurology education in the form of the Neurology Podcast since 2007. As podcasts were an initial step in the field of on-demand media, further technological evolution has resulted in increasing customization of a listener's audio experience. We believe a historical inflection point has been reached with the increasingly mainstream adoption of virtual assistant technology which allows for consumption of brief on-demand self-curated audio productions. As editors of the Neurology Podcast, we have introduced a new audio product to this technological landscape, the Neurology Minute. In doing so, we hope that curated on-demand educational audio will become a part of the daily routine of many practicing neurologists as we move into this new technological age.

Novel clinical features of glycine receptor antibody syndrome: A series of 17 cases

Objective

To describe novel clinical features of GlyRα1-IgG-positive patients.

Methods

Patients with a positive serum GlyRα1-IgG were identified during a 2-year period from July 2016 to December 2018 at 2 academic centers and followed prospectively. All patients in this series were evaluated in the Neuroimmunology and Autoimmune Neurology clinics at the University of Utah or the University of Colorado.

Results

Thirteen of 17 patients had phenotypes more typically associated with glutamic acid decarboxylase (GAD65) antibody syndromes, consisting of stiff-person syndrome (SPS) with parkinsonism or cerebellar signs. One patient with parkinsonism had a presentation similar to rapidly progressive multiple system atrophy with severe dysautonomia. Ten of 17 patients had various visual symptoms including visual snow, spider web-like images forming shapes and 3-dimensional images, palinopsia, photophobia, visual hallucinations, synesthesia, and intermittent diplopia. Three of 17 patients presented with primarily autoimmune epilepsy accompanied by psychiatric symptoms.

Conclusions

Clinicians should consider testing for GlyR antibodies in GAD65 antibody-negative or low-positive GAD65 antibody patients with SPS-like presentations, especially in the setting of atypical features such as visual disturbances, parkinsonism, or epilepsy.

Stiff person syndrome with Anti-GAD65 antibodies within the national veterans affairs health administration

INTRODUCTION

Stiff person syndrome (SPS) is a neurological disorder characterized by muscle rigidity primarily in the truncal muscles, commonly associated with autoantibodies to the glutamic acid-decarboxylase 65 kD receptor (GAD65). There is limited epidemiological information on patients with SPS.

METHODS

We performed a retrospective case review using the National United States Veterans Affairs Health Administration electronic medical record system. We analyzed prevalence, demographics, disease characteristics, and treatment outcomes in SPS patients who were anti-GAD65 antibody positive.

RESULTS

Fifteen patients met our criteria. Point prevalence was 2.06 per million, and period prevalence was 2.71 per million. Men to women ratio was 14:1. All patients benefitted from treatment with symptomatic antispasmodic agents. Ten of 15 patients received intravenous immunoglobulin, with a majority demonstrating stable or improved modified Rankin scores.

DISCUSSION

This investigation was a large North American epidemiological study of SPS with predominantly male patients. Symptomatic therapy was beneficial for most patients, with less clear sustained benefit of immunotherapy. Muscle Nerve 58:801-804, 2018.

Infection, Immunodeficiency, and Inflammatory Diseases in Autoimmune Neurology

When patients present with neurological syndromes, such as encephalopathy/encephalitis, meningitis, and/or myelopathy/myelitis, the differential diagnosis is often broad, including infectious, inflammatory, autoimmune, vascular, and neoplastic etiologies. Just with inflammatory and autoimmune etiologies alone, there are numerous causative diseases. A comprehensive history and physical examination investigating for extraneurologic manifestations of immune-mediated disease is often necessary. Moreover, evaluating for an underlying infection and/or immunodeficiency becomes a critical aspect to the workup. This article will focus on the association of viral infections and dysregulation of the immune system as triggers of autoimmunity, in addition to various systemic inflammatory diseases that can cause neurological disease either with or without an established rheumatological disorder.

Delayed LGI1 seropositivity in voltage-gated potassium channel (VGKC)-complex antibody limbic encephalitis

We utilise a clinical case to highlight why exclusion of voltage-gated potassium channel (VGKC)-complex autoantibody testing in serological evaluation of patients may delay or miss the diagnosis. A 68-year-old man presented with increasing involuntary movements consistent with faciobrachial dystonic seizures (FBDS). Initial evaluation demonstrated VGKC antibody seropositivity with leucine-rich glioma-inactivated 1 (LGI1) and contactin-associated protein-like 2 (CASPR2) seronegativity. Aggressive immunotherapy with methylprednisolone and plasmapheresis was started early in the course of his presentation. Following treatment with immunotherapy, the patient demonstrated clinical improvement. Repeat serum evaluation 4 months posthospitalisation remained seropositive for VGKC-complex antibodies, with development of LGI1 autoantibody seropositivity. VGKC-complex and LGI1 antibodies remained positive 12 months posthospitalisation. Our findings suggest that clinical symptoms can predate the detection of the antibody. We conclude that when suspicion for autoimmune encephalitis is high in the setting of VGKC autoantibody positivity, regardless of LGI1 or CASPR2 seropositivity, early immunotherapy and repeat testing should be considered.

Pathogenic implications of cerebrospinal fluid barrier pathology in neuromyelitis optica

Pathogenic autoantibodies associated with neuromyelitis optica (NMO) induce disease by targeting aquaporin-4 (AQP4) water channels enriched on astrocytic endfeet at blood–brain interfaces. AQP4 is also expressed at cerebrospinal fluid (CSF)–brain interfaces, such as the pial glia limitans and the ependyma and at the choroid plexus blood–CSF barrier. However, little is known regarding pathology at these sites in NMO. Therefore, we evaluated AQP4 expression, microglial reactivity, and complement deposition at pial and ependymal surfaces and in the fourth ventricle choroid plexus in 23 autopsy cases with clinically and/or pathologically confirmed NMO or NMO spectrum disorder. These findings were compared to five cases with multiple sclerosis, five cases of choroid plexus papilloma, and five control cases without central nervous system disease. In the NMO cases, AQP4 immunoreactivity was reduced relative to control levels in the pia (91%; 21/23), ependyma (56%; 9/16), and choroid plexus epithelium (100%; 12/12). AQP4 immunoreactivity was normal in MS cases in these regions. Compared to MS, NMO cases also showed a focal pattern of pial and ependymal complement deposition and more pronounced microglial reactivity. In addition, AQP4 loss, microglial reactivity, and complement deposition colocalized along the pia and ependyma only in NMO cases. Within the choroid plexus, AQP4 loss was coincident with C9neo immunoreactivity on epithelial cell membranes only in NMO cases. These observations demonstrate that NMO immunopathology extends beyond perivascular astrocytic foot processes to include the pia, ependyma, and choroid plexus, suggesting that NMO IgG-induced pathological alterations at CSF–brain and blood–CSF interfaces may contribute to the occurrence of ventriculitis, leptomeningitis, and hydrocephalus observed among NMO patients. Moreover, disruption of the blood–CSF barrier induced by binding of NMO IgG to AQP4 on the basolateral surface of choroid plexus epithelial cells may provide a unique portal for entry of the pathogenic antibody into the central nervous system.

Antineuronal Nuclear Autoantibody Type 1/Anti-Hu-Associated Opsoclonus Myoclonus and Epilepsia Partialis Continua: Case Report and Literature Review

BACKGROUND

Opsoclonus-myoclonus syndrome is a rare clinical condition that has been associated with neuroblastoma. There are few reported examples of ANNA-1/anti-Hu antibodies in children with neuroblastoma and opsoclonus-myoclonus, all in children aged less than three years of age.

METHODS

We describe the new onset of focal seizures without alteration of consciousness and opsoclonus-myoclonus in an 11-year-old girl with ANNA-1/anti-Hu positivity and a paraspinal ganglioneuroblastoma. A systematic review of the literature of children with ANNA-1/anti-Hu positivity and malignancy was also performed.

RESULTS

Fourteen patients were identified, eight of whom had opsoclonus-myoclonus. Although epilepsia partialis continua has been described in association with several neuronal autoantibodies, association with ANNA-1/anti-Hu has not been reported.

CONCLUSIONS

We describe epilepsia partialis continua in a child with ANNA-1/anti-Hu antibodies and neuroblastoma. Testing for antineuronal antibodies should be considered in children presenting with either opsoclonus-myoclonus or epilepsia partialis continua.

Voltage-gated calcium channel autoimmune cerebellar degeneration: Case and study of cytotoxicity

Objectives:

To describe response to treatment in a patient with autoantibodies against voltage-gated calcium channels (VGCCs) who presented with autoimmune cerebellar degeneration and subsequently developed Lambert-Eaton myasthenic syndrome (LEMS), and to study the effect of the patient's autoantibodies on Purkinje cells in rat cerebellar slice cultures.

Methods:

Case report and study of rat cerebellar slice cultures incubated with patient VGCC autoantibodies.

Results:

A 53-year-old man developed progressive incoordination with ataxic speech. Laboratory evaluation revealed VGCC autoantibodies without other antineuronal autoantibodies. Whole-body PET scans 6 and 12 months after presentation detected no malignancy. The patient improved significantly with IV immunoglobulin G (IgG), prednisone, and mycophenolate mofetil, but worsened after IV IgG was halted secondary to aseptic meningitis. He subsequently developed weakness with electrodiagnostic evidence of LEMS. The patient's IgG bound to Purkinje cells in rat cerebellar slice cultures, followed by neuronal death. Reactivity of the patient's autoantibodies with VGCCs was confirmed by blocking studies with defined VGCC antibodies.

Conclusions:

Autoimmune cerebellar degeneration associated with VGCC autoantibodies may precede onset of LEMS and may improve with immunosuppressive treatment. Binding of anti-VGCC antibodies to Purkinje cells in cerebellar slice cultures may be followed by cell death. Patients with anti-VGCC autoantibodies may be at risk of irreversible neurologic injury over time, and treatment should be initiated early.

Anti-Yo antibody uptake and interaction with its intracellular target antigen causes Purkinje cell death in rat cerebellar slice cultures: a possible mechanism for paraneoplastic cerebellar degeneration in humans with gynecological or breast cancers

Anti-Yo antibodies are immunoglobulin G (IgG) autoantibodies reactive with a 62 kDa Purkinje cell cytoplasmic protein. These antibodies are closely associated with paraneoplastic cerebellar degeneration in the setting of gynecological and breast malignancies. We have previously demonstrated that incubation of rat cerebellar slice cultures with patient sera and cerebrospinal fluid containing anti-Yo antibodies resulted in Purkinje cell death. The present study addressed three fundamental questions regarding the role of anti-Yo antibodies in disease pathogenesis: 1) Whether the Purkinje cell cytotoxicity required binding of anti-Yo antibody to its intraneuronal 62 kDa target antigen; 2) whether Purkinje cell death might be initiated by antibody-dependent cellular cytotoxicity rather than intracellular antibody binding; and 3) whether Purkinje cell death might simply be a more general result of intracellular antibody accumulation, rather than of specific antibody-antigen interaction. In our study, incubation of rat cerebellar slice cultures with anti-Yo IgG resulted in intracellular antibody binding, and cell death. Infiltration of the Purkinje cell layer by cells of macrophage/microglia lineage was not observed until extensive cell death was already present. Adsorption of anti-Yo IgG with its 62 kDa target antigen abolished both antibody accumulation and cytotoxicity. Antibodies to other intracellular Purkinje cell proteins were also taken up by Purkinje cells and accumulated intracellularly; these included calbindin, calmodulin, PCP-2, and patient anti-Purkinje cell antibodies not reactive with the 62 kDa Yo antigen. However, intracellular accumulation of these antibodies did not affect Purkinje cell viability. The present study is the first to demonstrate that anti-Yo antibodies cause Purkinje cell death by binding to the intracellular 62 kDa Yo antigen. Anti-Yo antibody cytotoxicity did not involve other antibodies or factors present in patient serum and was not initiated by brain mononuclear cells. Purkinje cell death was not simply due to intraneuronal antibody accumulation.

Serum ferritin is elevated in amyotrophic lateral sclerosis patients

Our objective was to measure serum ferritin levels, which reflect iron metabolism, in ALS patients versus healthy and disease controls, and determine whether serum ferritin levels correlate with survival. We retrospectively analyzed data from 138 ALS patients, 152 healthy controls, and 82 disease controls. Gender, age, site of onset, and dates of symptom onset and death were recorded. Survival was defined as the time from symptom onset to death. Serum ferritin levels were measured using immunoassay. ANOVA and Pearson's correlation were used to compare ferritin levels between groups and test the association between ferritin levels and age and survival. Ferritin levels were categorized into high and low groups, and Kaplan-Meier analysis performed. Results showed that gender proportions differed between ALS patients versus healthy and disease controls, and gender affected serum ferritin levels. Ferritin comparisons were stratified for gender. In both males and females, ferritin levels were higher in ALS patients versus healthy and disease controls. However, ferritin levels were unrelated to survival in either gender, by tests of association or survival analysis. In conclusion, ALS patients have altered iron metabolism that is not simply due to the presence of neurological disease. Serum ferritin levels alone are not sufficient to predict survival.

Neuronal uptake of anti-Hu antibody, but not anti-Ri antibody, leads to cell death in brain slice cultures

BACKGROUND

Anti-Hu and anti-Ri antibodies are paraneoplastic immunoglobulin (Ig)G autoantibodies which recognize cytoplasmic and nuclear antigens present in all neurons. Although both antibodies produce similar immunohistological labeling, they recognize different neuronal proteins. Both antibodies are associated with syndromes of central nervous system dysfunction. However, the neurological deficits associated with anti-Hu antibody are associated with neuronal death and are usually irreversible, whereas neurological deficits in patients with anti-Ri antibody may diminish following tumor removal or immunosuppression.

METHODS

To study the effect of anti-Hu and anti-Ri antibodies on neurons, we incubated rat hippocampal and cerebellar slice cultures with anti-Hu or anti-Ri sera from multiple patients. Cultures were evaluated in real time for neuronal antibody uptake and during prolonged incubation for neuronal death. To test the specificity of anti-Hu antibody cytotoxic effect, anti-Hu serum IgG was incubated with rat brain slice cultures prior to and after adsorption with its target Hu antigen, HuD.

RESULTS

We demonstrated that: 1) both anti-Hu and anti-Ri antibodies were rapidly taken up by neurons throughout both cerebellum and hippocampus; 2) antibody uptake occurred in living neurons and was not an artifact of antibody diffusion into dead cells; 3) intracellular binding of anti-Hu antibody produced neuronal cell death, whereas uptake of anti-Ri antibody did not affect cell viability during the period of study; and 4) adsorption of anti-Hu antisera against HuD greatly reduced intraneuronal IgG accumulation and abolished cytotoxicity, confirming specificity of antibody-mediated neuronal death.

CONCLUSIONS

Both anti-Hu and anti-Ri antibodies were readily taken up by viable neurons in slice cultures, but the two antibodies differed markedly in terms of their effects on neuronal viability. The ability of anti-Hu antibodies to cause neuronal death could account for the irreversible nature of paraneoplastic neurological deficits in patients with this antibody response. Our results raise questions as to whether anti-Ri antibody might initially induce reversible neuronal dysfunction, rather than causing cell death. The ability of IgG antibodies to access and react with intracellular neuronal proteins could have implications for other autoimmune diseases involving the central nervous system.

AQP4 autoantibody assay performance in clinical laboratory service

Objective:

To compare performance of contemporary aquaporin-4–immunoglobulin (Ig) G assays in clinical service.

Methods:

Sera from neurologic patients (4 groups) and controls were tested initially by service ELISA (recombinant human aquaporin-4, M1 isoform) and then by cell-based fluorescence assays: fixed (CBA, M1-aquaporin-4, observer-scored) and live (fluorescence-activated cell sorting [FACS], M1 and M23 aquaporin-4 isoforms). Group 1: all Mayo Clinic patients tested from January to May 2012; group 2: consecutive aquaporin-4-IgG–positive patients from September 2011 (Mayo and non-Mayo); group 3: suspected ELISA false-negatives from 2011 to 2013 (physician-reported, high likelihood of neuromyelitis optica spectrum disorders [NMOSDs] clinically); group 4: suspected ELISA false-positives (physician-reported, not NMOSD clinically).

Results:

Group 1 (n = 388): M1-FACS assay performed optimally (areas under the curves: M1 = 0.64; M23 = 0.57 [p = 0.02]). Group 2 (n = 30): NMOSD clinical diagnosis was confirmed by: M23-FACS, 24; M1-FACS, 23; M1-CBA, 20; and M1-ELISA, 18. Six results were suspected false-positive: M23-FACS, 2; M1-ELISA, 2; and M23-FACS, M1-FACS, and M1-CBA, 2. Group 3 (n = 31, suspected M1-ELISA false-negatives): results were positive for 5 sera: M1-FACS, 5; M23-FACS, 3; and M1-CBA, 2. Group 4 (n = 41, suspected M1-ELISA false-positives): all negative except 1 (positive only by M1-CBA). M1/M23-cotransfected cells expressing smaller membrane arrays of aquaporin-4 yielded fewer false- positive FACS results than M23-transfected cells.

Conclusion:

Aquaporin-4-transfected CBAs, particularly M1-FACS, perform optimally in aiding NMOSD serologic diagnosis. High-order arrays of M23-aquaporin-4 may yield false-positive results by binding IgG nonspecifically.

Purkinje cell cytoplasmic antibody type 1 (anti-Yo) autoimmunity in a child with Down syndrome

IMPORTANCE

Purkinje cell cytoplasmic antibody type 1 (PCA-1)-IgG (or anti-Yo) is characteristically detected in women with gynecological or breast adenocarcinoma. We describe 2 unique scenarios occurring in 1 patient: PCA-1 paraneoplastic autoimmunity in a child, and a paraneoplastic neurological disorder in the context of Down syndrome.

OBSERVATIONS

A child with Down syndrome and a history of adrenocortical carcinoma resected at age 1 year presented at age 7 years with cerebellar ataxia of subacute onset. Paraneoplastic serological and cerebrospinal fluid evaluations revealed PCA-1. Serological and biochemical studies also supported a diagnosis of subclinical autoimmune hypothyroidism. Extensive serum, urine, and radiological testing did not reveal a new or recurrent neoplasm. Neurological improvements after standard immunotherapy were lacking.

CONCLUSIONS AND RELEVANCE

Solid organ neoplasms are uncommon among patients with Down syndrome, but organ-specific autoimmune diseases are common. In our patient, Down syndrome-related impaired T regulatory lymphocyte function (previously reported) may have resulted in both enhanced immunity against an undetected solid neoplasm and paraneoplastic neurological (PCA-1) autoimmunity.

Childhood onset of stiff-man syndrome

IMPORTANCE

Reports of pediatric-onset stiff-man syndrome (SMS) are rare. This may be an underrecognized disorder in child neurology practice.

OBJECTIVE

To describe patients with disorders in the SMS spectrum beginning in childhood.

DESIGN, SETTING, AND PARTICIPANTS

This study was a medical record review and serological evaluation conducted at child and adult neurology clinics at the Mayo Clinic, Rochester, Minnesota. Systematic review of the literature was conducted of patients who presented from 1984-2012 with onset of symptomatic SMS occurring at age 18 years or younger.

MAIN OUTCOMES AND MEASURES

Response to symptomatic and immunotherapies, patient and physician reported, including modified Rankin scale.

RESULTS

We identified 8 patients with childhood-onset SMS, representing 5% of patients with SMS evaluated at Mayo Clinic during a period of 29 years (4 were girls). The median age at symptom onset was 11 years (range, 1-14 years). The diagnosis in 3 patients was not established until adulthood (median symptom duration at diagnosis, 14 years; range, 0-46 years). The phenotypes encountered were: classic SMS (n = 5, involving the low back and lower extremities), variant SMS (n = 2, limited to 1 limb [with dystonic posture] or back), and progressive encephalomyelitis with rigidity and myoclonus (n = 1). Initial misdiagnoses included functional movement disorder (n = 2), generalized dystonia and parkinsonism (n = 1), and hereditary spastic paraparesis (n = 1). Six patients had 1 or more coexisting autoimmune disorders: type 1 diabetes mellitus (n = 4), thyroid disease (n = 2), and vitiligo (n = 2). Serologic study results revealed glutamic acid decarboxylase 65-IgG in all cases (median value, 754 nmol/L; range, 0.06-3847 nmol/L; normal value, ≤ 0.02 nmol/L) and glycine receptor antibody in 3 cases. Improvements were noted with symptomatic therapy (diazepam, 6 of 6 patients treated, and oral baclofen, 3 of 3 treated) and immunotherapy (intravenous immune globulin, 3 of 4 treated and plasmapheresis, 3 of 4 treated). The 3 patients with glycine receptor antibody all improved with immunotherapy. At last follow-up, 4 patients had mild or no symptoms, but 4 had moderate or severe residual symptoms and required maintenance symptomatic therapy (n = 5) and immunotherapy (n = 4). Ten of 12 pediatric SMS cases identified by literature review had a severe whole-body phenotype resembling progressive encephalomyelitis with rigidity and myoclonus.

CONCLUSIONS AND RELEVANCE

Childhood-onset SMS is a rare but underrecognized and treatable disorder. Serological and electrophysiological testing aid diagnosis.