B Cell Depletion and SARS-CoV-2 Vaccine Responses in Neuroimmunologic Patients

OBJECTIVE

The study was undertaken to assess the impact of B cell depletion on humoral and cellular immune responses to severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) vaccination in patients with various neuroimmunologic disorders on anti-CD20 therapy. This included an analysis of the T cell vaccine response to the SARS-CoV-2 Delta variant.

METHODS

We investigated prospectively humoral and cellular responses to SARS-CoV-2 mRNA vaccination in 82 patients with neuroimmunologic disorders on anti-CD20 therapy and 82 age- and sex-matched healthy controls. For quantification of antibodies, the Elecsys anti-SARS-CoV-2 viral spike (S) immunoassay against the receptor-binding domain (RBD) was used. IFN-gamma enzyme-linked immunosorbent spot assays were performed to assess T cell responses against the SARS-CoV-2 Wuhan strain and the Delta variant.

RESULTS

SARS-CoV-2-specific antibodies were found less frequently in patients (70% [57/82]) compared with controls (82/82 [100%], p < 0.001). In patients without detectable B cells (<1 B cell/mcl), seroconversion rates and antibody levels were lower compared to nondepleted (≥1 B cell/mcl) patients (p < 0.001). B cell levels ≥1 cell/mcl were sufficient to induce seroconversion in our cohort of anti-CD20 treated patients. In contrast to the antibody response, the T-cell response against the Wuhan strain and the Delta variant was more pronounced in frequency (p < 0.05) and magnitude (p < 0.01) in B-cell depleted compared to nondepleted patients.

INTERPRETATION

Antibody responses to SARS-CoV-2 mRNA vaccinnation can be attained in patients on anti-CD20 therapy by the onset of B cell repopulation. In the absence of B cells, a strong T cell response is generated which may help to protect against severe coronavirus disease 2019 (COVID-19) in this high-risk population. ANN NEUROL 2022;91:342-352.

Clinical and Laboratory Features in Anti-NF155 Autoimmune Nodopathy

BACKGROUND AND OBJECTIVES

To study the clinical and laboratory features of antineurofascin-155 (NF155)-positive autoimmune nodopathy (AN).

METHODS

Patients with anti-NF155 antibodies detected on routine immunologic testing were included. Clinical characteristics, treatment response, and functional scales (modified Rankin Scale [mRS] and Inflammatory Rasch-built Overall Disability Scale [I-RODS]) were retrospectively collected at baseline and at the follow-up. Autoantibody and neurofilament light (NfL) chain levels were analyzed at baseline and at the follow-up.

RESULTS

Forty NF155+ patients with AN were included. Mean age at onset was 42.4 years. Patients presented with a progressive (75%), sensory motor (87.5%), and symmetric distal-predominant weakness in upper (97.2%) and lower extremities (94.5%), with tremor and ataxia (75%). Patients received a median of 3 (2-4) different treatments in 46 months of median follow-up. Response to IV immunoglobulin (86.8%) or steroids (72.2%) was poor in most patients, whereas 77.3% responded to rituximab. HLA-DRB1*15 was detected in 91.3% of patients. IgG4 anti-NF155 antibodies were predominant in all patients; anti-NF155 titers correlated with mRS within the same patient (r = 0.41, p = 0.004). Serum NfL (sNfL) levels were higher in anti-NF155+ AN than in healthy controls (36.47 vs 7.56 pg/mL, p < 0.001) and correlated with anti-NF155 titers (r = 0.43, p = 0.001), with I-RODS at baseline (r = -0.88, p < 0.001) and with maximum I-RODS achieved (r = -0.58, p = 0.01). Anti-NF155 titers and sNfL levels decreased in all rituximab-treated patients.

DISCUSSION

Anti-NF155 AN presents a distinct clinical profile and good response to rituximab. Autoantibody titers and sNfL are useful to monitor disease status in these patients. The use of untagged-NF155 plasmids minimizes the detection of false anti-NF155+ cases.

CLASSIFICATION OF EVIDENCE

This study provides Class IV evidence that anti-NF155 antibodies associate with a specific phenotype and response to rituximab.

IgG4-related autoimmune manifestations in Alemtuzumab-treated multiple sclerosis patients

We aimed to determine whether Alemtuzumab-induced immune reconstitution affects immunoglobulin and complement levels in the serum of Relapsing-Remitting Multiple Sclerosis (RRMS) patients. IgG4-levels were increased 24-months after treatment initiation compared to baseline levels in twenty-nine patients. Alemtuzumab-treated patients with the highest IgG4-levels were more prone to thyroid-related autoimmune manifestations and specific autoimmune adverse events such as Crohn's disease, Graves' disease, and hemolytic anemia. Compared to baseline, total IgG-levels showed a trend towards reduced levels following two-courses of Alemtuzumab, but no significant change of C3 and/or C4-levels was observed. In conclusion, monitoring of IgG4-levels can serve as a marker for secondary autoimmunity risk in multiple sclerosis patients treated with Alemtuzumab.

Single-cell approaches to investigate B cells and antibodies in autoimmune neurological disorders

Autoimmune neurological disorders, including neuromyelitis optica spectrum disorder, anti-N-methyl-D-aspartate receptor encephalitis, anti-MOG antibody-associated disorders, and myasthenia gravis, are clearly defined by the presence of autoantibodies against neurological antigens. Although these autoantibodies have been heavily studied for their biological activities, given the heterogeneity of polyclonal patient samples, the characteristics of a single antibody cannot be definitively assigned. This review details the findings of polyclonal serum and CSF studies and then explores the advances made by single-cell technologies to the field of antibody-mediated neurological disorders. High-resolution single-cell methods have revealed abnormalities in the tolerance mechanisms of several disorders and provided further insight into the B cells responsible for autoantibody production. Ultimately, several factors, including epitope specificity and binding affinity, finely regulate the pathogenic potential of an autoantibody, and a deeper appreciation of these factors may progress the development of targeted immunotherapies for patients.

Exploratory investigation on antibodies to GluN1 and cognitive dysfunction in patients with chronic autoimmune psychosis

INTRODUCTION

Mild cognitive dysfunction has been implicated in a number of psychiatric diseases and affects social functioning. Although clinical criteria were recently proposed for autoimmune psychosis (AP), biomarkers have not yet been established for the severity and prognosis of cognitive dysfunction. We herein investigated the relationships between 3 types of serum antibodies and cognitive dysfunction in chronic psychiatric patients suspected of AP.

METHODS

We included 31 patients suspected of AP and obtained information on their clinical characteristics. Three types of autoantibodies (the anti-N-methyl-_D-aspartate receptor (anti-NMDAR Ab), anti-N-terminal of GluN1 (anti-GluN1-NT Ab), and anti-thyroid antibodies) were evaluated in serum. Cognitive function was assessed using Wechsler Adult Intelligence Scale-III. We examined the relationships between serum autoantibodies and cognitive dysfunction in patients using multiple regression models.

RESULTS

Serum titers of anti-GluN1-NT Ab significantly contributed to the estimated score of working memory (B= -55.85, β= -0.46, p= 0.01), while no correlation was observed between the other 2 types of antibodies and cognitive function.

CONCLUSIONS

The present results indicate the potential of serum anti-GluN1-NT Ab as a biomarker for the severity and prognosis of cognitive dysfunction underlying various psychiatric symptoms in patients with AP. The pathological significance of anti-GluN1-NT Ab needs to be verified in future studies.

Anti-leucine-rich Glioma-inactivated-1 Encephalitis with Faciobrachial Dystonic Seizures and Behavioral Problems: A Case Report

Anti-Leucine-rich glioma-inactivated-1 encephalitis is a subtype of autoimmune encephalitis characterized by cognitive impairment, faciobrachial dystonic seizures, and behavioural changes. There is no reported case from Nepal. We report a case of a 54-year old male who presented with abnormal body movement, behavioural changes, rapid eye movement sleep behavioural changes, and cognitive decline. Investigations revealed magnetic resonance imaging findings of fluid-attenuated inversion recovery intensity signal in bilateral temporal lobes with anti-leucine-rich glioma-inactivated-1 antibody in serum leading to diagnosis of anti-leucine-rich glioma-inactivated-1 encephalitis. He was treated with steroids and intravenous immunoglobulin. Timely diagnosis is vital to prevent complications and improve outcomes.

Neurologic syndromes related to anti-GAD65: Clinical and serologic response to treatment

OBJECTIVE

Antibodies against glutamic acid decarboxylase 65 (anti-GAD65) are associated with a number of neurologic syndromes. However, their pathogenic role is controversial. Our objective was to describe clinical and paraclinical characteristics of anti-GAD65 patients and analyze their response to immunotherapy.

METHODS

Retrospectively, we studied patients (n = 56) with positive anti-GAD65 and any neurologic symptom. We tested serum and CSF with ELISA, immunohistochemistry, and cell-based assay. Accordingly, we set a cutoff value of 10,000 IU/mL in serum by ELISA to group patients into high-concentration (n = 36) and low-concentration (n = 20) groups. We compared clinical and immunologic features and analyzed response to immunotherapy.

RESULTS

Classical anti-GAD65-associated syndromes were seen in 34/36 patients with high concentration (94%): stiff-person syndrome (7), cerebellar ataxia (3), chronic epilepsy (9), limbic encephalitis (9), or an overlap of 2 or more of the former (6). Patients with low concentrations had a broad, heterogeneous symptom spectrum. Immunotherapy was effective in 19/27 treated patients (70%), although none of them completely recovered. Antibody concentration reduction occurred in 15/17 patients with available pre- and post-treatment samples (median reduction 69%; range 27%-99%), of which 14 improved clinically. The 2 patients with unchanged concentrations showed no clinical improvement. No differences in treatment responses were observed between specific syndromes.

CONCLUSION

Most patients with high anti-GAD65 concentrations (>10,000 IU/mL) showed some improvement after immunotherapy, unfortunately without complete recovery. Serum antibody concentrations' course might be useful to monitor response. In patients with low anti-GAD65 concentrations, especially in those without typical clinical phenotypes, diagnostic alternatives are more likely.

Can serum GAD65 antibody levels predict neurological disease or cancer?

The clinical relevance of antibodies that bind to glutamic acid decarboxylase 65 (GAD65) is controversial regarding diagnostic utility in screening for neurological disease or cancer. We did a retrospective study of 3152 GAD65 antibody-positive patients to examine whether analysis of the antibody levels could predict neurological disease or cancer. Serum GAD65 antibody levels were not associated with any of the following groups: neurological disease, neurological disease and diabetes, diabetes only, no neurological diagnosis and no diabetes mellitus, or cancer. Analysis of serum GAD65 antibody levels had no prognostic value in neurological disease or cancer. GAD65 antibodies should therefore be measured in selective cases of autoimmune neurological diseases.

Neonatal detection of Aicardi Goutières Syndrome by increased C26:0 lysophosphatidylcholine and interferon signature on newborn screening blood spots

BACKGROUND

Aicardi Goutières Syndrome (AGS) is a heritable interferonopathy associated with systemic autoinflammation causing interferon (IFN) elevation, central nervous system calcifications, leukodystrophy and severe neurologic sequelae. An infant with TREX1 mutations was recently found to have abnormal C26:0 lysophosphatidylcholine (C26:0 Lyso-PC) in a newborn screening platform for X-linked adrenoleukodystrophy, prompting analysis of this analyte in retrospectively collected samples from individuals affected by AGS.

METHODS

In this study, we explored C26:0 Lyso-PC levels and IFN signatures in newborn blood spots and post-natal blood samples in 19 children with a molecular and clinical diagnosis of AGS and in the blood spots of 22 healthy newborns. We used Nanostring nCounter™ for IFN-induced gene analysis and a high-performance liquid chromatography with tandem mass spectrometry (HPLC MS/MS) newborn screening platform for C26:0 Lyso-PC analysis.

RESULTS

Newborn screening cards from patients across six AGS associated genes were collected, with a median disease presentation of 2months. Thirteen out of 19 (68%) children with AGS had elevations of first tier C26:0 Lyso-PC (>0.4μM), that would have resulted in a second screen being performed in a two tier screening system for X-linked adrenoleukodystrophy (X-ALD). The median (95%CI) of first tier C26:0 Lyso-PC values in AGS individuals (0.43μM [0.37-0.48]) was higher than that seen in controls (0.21μM [0.21-0.21]), but lower than X-ALD individuals (0.72μM [0.59-0.84])(p<0.001). Fourteen of 19 children had elevated expression of IFN signaling on blood cards relative to controls (Sensitivity 73.7%, 95%CI 51-88%, Specificity 95%, 95% CI 78-99%) including an individual with delayed disease presentation (36months of age). All five AGS patients with negative IFN signature at birth had RNASEH2B mutations. Consistency of agreement between IFN signature in neonatal and post-natal samples was high (0.85).

CONCLUSION

This suggests that inflammatory markers in AGS can be identified in the newborn period, before symptom onset. Additionally, since C26:0 Lyso-PC screening is currently used in X-ALD newborn screening panels, clinicians should be alert to the fact that AGS infants may present as false positives during X-ALD screening.

Autoimmune Epilepsy

PURPOSE OF REVIEW

This review presents recent developments in the clinical features, immunologic basis, and treatment options for autoimmune encephalitis, seizures, and epilepsy.

RECENT FINDINGS

In addition to the expansion of our knowledge on classic paraneoplastic limbic encephalitis with onconeural antibodies, recent years have witnessed the development of the category of encephalitis associated with antibodies directed toward neuronal surface antigens. Antibodies against the voltage-gated potassium channel are, in fact, directed toward an array of targets within a large molecular complex. The most common target, leucine-rich, glioma inactivated 1 (LGI1), is associated with a syndrome of limbic encephalitis, sometimes preceded by disease-specific faciobrachial dystonic seizures, which could allow early diagnosis and treatment. Encephalitis with N-methyl-D-aspartate (NMDA) receptor antibodies, only discovered a few years ago, has emerged as the leading syndrome of this new category. Its clinical features and EEG signature are well defined, which should allow prompt recognition and treatment. The list of antibodies is still growing as new antibodies are identified that recognize other synaptic proteins, such as the γ-aminobutyric acid (GABA), α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA), and glycine receptors. The role of glutamic acid decarboxylase 65 (GAD65) antibodies is still a controversy, as is the cause of Rasmussen encephalitis and syndromes of cryptogenic refractory status epilepticus and the mechanisms of seizures in systemic autoimmune diseases. A link between autoimmunity and epilepsy has been substantiated by large epidemiologic studies, but the nature of the causality requires more research.

SUMMARY

Autoimmune encephalitis is an important cause of seizures to recognize as it entails a specific therapeutic approach. Paraneoplastic limbic encephalitis and NMDA receptor and LGI1 encephalitis are well-characterized immunoclinical associations. Other syndromes and antibodies are being actively identified and described. A concept of autoimmune epilepsy is emerging and, if confirmed, is likely to alter the therapeutic approach and improve the outcome of some patients with pharmacoresistant epilepsy.

Central hypothyroidism in a patient with pituitary autoimmunity: evidence for TSH-independent thyroid hormone synthesis

CONTEXT

Acquired central hypothyroidism is rare, especially when isolated, and is typically associated with detectable, although biologically inactive, serum TSH.

OBJECTIVE

We describe a 56-yr-old woman with profound central hypothyroidism and partial central hypoadrenalism, in the absence of other endocrine abnormalities. In contrast to most cases of central hypothyroidism, serum TSH remained undetectable for 9 months before the initiation of thyroid hormone and hydrocortisone treatment. A test for pituitary autoantibody was moderately positive. Serum free T(4), serum T(3), and neck radioiodine uptake were low but detectable. The thyroid and pituitary glands appeared morphologically normal on neck ultrasound and head magnetic resonance imaging, respectively.

SETTINGS

The study was conducted in a tertiary academic medical center.

CONCLUSIONS

This case illustrates the variable clinical presentation of pituitary autoimmunity. The persistence of low but detectable thyroid hormone levels and radioiodine neck uptake in the absence of TSH suggests that significant TSH-independent thyroid hormone synthesis may occur in the normal thyroid.

Autoimmunity in autism

Autism spectrum disorders is a heterogenous group of neurodevelopmental disorders, the etiology or etiologies of which remain unknown. Increasing evidence of autoimmune phenomena in individuals with autism could represent the presence of altered or inappropriate immune responses in this disorder, and this immune system dysfunction may represent novel targets for treatment. Furthermore, in recent studies, antibodies directed against the fetal brain have been detected in some mothers of children with autism; these antibodies have the ability to alter behavioral outcomes in the offspring of animal models. A better understanding of the involvement of the immune response in early brain development, with respect to autism, may have important therapeutic implications.

PET scan in clinically suspected paraneoplastic neurological syndromes: a 6-year prospective study in a regional neuroscience unit

BACKGROUND

The role of PET in the diagnosis of paraneoplastic neurological syndromes (PNS) has previously been reported in retrospective studies, from specialized neuro-oncology units, often selecting patients with positive paraneoplastic antibodies.

OBJECTIVES

To prospectively assess the usefulness of PET in detecting malignancy in patients clinically suspected of having PNS.

METHODS

PET was performed in patients suspected of PNS within 4 weeks of the normal CT body scan. All patients were followed up.

RESULTS

Eighty patients suspected of having PNS underwent PET. 18/80 (23%) were abnormal and suspicious of malignancy. The total number of definite and probable PNS with abnormal PET was 11/18 (61%). The total number of definite and probable PNS with a normal PET was 3/62 (5%). Only 50% of patients with biopsy-proven malignancy were positive for paraneoplastic antibodies. The prevalence of abnormal PET in patients presenting with classical PNS was 41% as opposed to 21% in patients with non-classical PNS. The sensitivity and specificity of PET in diagnosing PNS was 75% and 87% respectively.

CONCLUSIONS

PET is a valuable tool in clinically suspected PNS. Its use should not be restricted to specialized neuro-oncology units or in patients with positive paraneoplastic antibodies. Positive yield is the highest amongst patients with classical PNS.

Antibodies to myelin protein zero (P0) protein as markers of auto-immune inner ear diseases

BACKGROUND/AIMS

The inner ear can be the target of autoimmune disorders. Recognition of autoimmune inner ear disease is important, as it is one of the very few forms of sensorineural hearing loss (HL) that can be successfully treated by medical therapy. The aim of this study was to evaluate whether the detection of antibodies to myelin protein P0 (MPZ) could be a diagnostic test for inner ear disease of autoimmune cause.

METHODS

This multicentric prospective study included 129 patients: patients with progressive sensorineural HL or with Menière's disease, together with their control group corresponding to patients with similar symptoms, but of presumably known origin. Detection of antibodies to myelin P0 protein was performed by using western blots. NORMAL: The prevalence of antibodies to myelin P0 protein in patients with rapidly progressive HL was not statistically different from that of the control group corresponding to genetic HL patients (30 versus 28%). In patients with Menière's disease, the prevalence was lower than that of the control group corresponding to patients with benign paroxysmal positional vertigo (5.4 versus 18.7%). No patient with auto-immune disease had antibodies to myelin P0 protein.

CONCLUSIONS

The sole presence of antibodies to myelin P0 may not be used as a marker of inner ear disease of autoimmune origin.

Antiphospholipid antibodies in blood and cerebrospinal fluids of patients with psychosis

Antiphospholipid antibodies (aPL) have been reported in the cerebrospinal fluids (CSF) of neurology patients but no CSF studies with psychiatric patients exist. We tested serum from 100 hospitalized psychotic patients having hallucinations and/or delusions for aPL. Patients with positive serum aPL findings were asked to submit CSF for aPL testing. Five CSF samples had aPL specificities not found in the patient's serum suggesting the possibility of intrathecal synthesis. Specificity and isotype discordance between CSF and blood aPL in these psychiatric patients implicates a central nervous system independent autoimmune process that may have an underlying association with the pathophysiology of their diseases.

Immune reactivity towards insulin, its amyloid and protein S100B in blood sera of Parkinson's disease patients

Peripheral immune responses can be sensitive indicators of disease pathology. We evaluated the autoimmune reactions to endocrine (insulin) and astrocytical (S100B) biomarkers in the blood sera of 26 Parkinson's disease (PD) patients compared with controls by using ELISA. We found a statistically significant increase of the autoimmune responses to both antigens in PD patients compared with controls with a mean increase of 70% and 50% in the autoimmune reactions towards insulin and S100B, respectively. Heterogeneity of the immune responses observed in patients may reflect the modulating effect of multiple variables associated with neurodegeneration and also changes in the basic mechanisms of individual autoimmune reactivity. We did not detect any pronounced immune reactions towards insulin amyloid fibrils and oligomers in PD patients, indicating that an amyloid-specific conformational epitope is not involved in immune recognition of this amyloid type, while sequential epitope of native insulin is hidden within the amyloid structures. Immune reactions towards S100B and insulin may reflect the neurodegenerative brain damaging processes and impaired insulin homeostasis occurring in PD.

Spectrum of neurological diseases associated with antibodies to minor gangliosides GM1b and GalNAc-GD1a

The authors reported the neurological disease spectrum associated with autoantibodies against minor gangliosides GM1b and GalNAc-GD1a. IgG and IgM antibody reactivity against gangliosides GM1, GM2, GM1b, GD1a, GalNAc-GD1a and GQ1b was investigated in sera from 7000 consecutive patients who had various neurological conditions. The clinical diagnoses for 456 anti-GM1b-positive patients were Guillain-Barré syndrome (GBS, 71%), atypical GBS with preserved deep tendon reflexes (12%), Fisher syndrome (10%), Bickerstaff's brainstem encephalitis (2%), ataxic GBS (2%) and acute ophthalmoparesis (1%). For 193 anti-GalNAc-GD1a-positive patients, the diagnoses were GBS (70%), atypical GBS (16%), Fisher syndrome (10%) and Bickerstaff's brainstem encephalitis (3%). Of the patients with GBS or atypical GBS, 28% of 381 anti-GM1b-positive and 31% of 166 anti-GalNAc-GD1a-positive patients had neither anti-GM1 nor anti-GD1a antibodies. Of those patients with Fisher syndrome, Bickerstaff's brainstem encephalitis, ataxic GBS or acute ophthalmoparesis, 33% of 67 anti-GM1b-positive, and 52% of 25 anti-GalNAc-GD1a-positive patients had no anti-GQ1b antibodies. Autoantibodies against GM1b and GalNAc-GD1a are associated with GBS, Fisher syndrome and related conditions. These antibodies should provide useful serological markers for identifying patients who have atypical GBS with preserved deep tendon reflexes, ataxic GBS, Bickerstaff's brainstem encephalitis or acute ophthalmoparesis, especially for those who have no antibodies to GM1, GD1a or GQ1b. A method to prepare GM1b was developed.

Antibody-mediated neuronal cell signaling in behavior and movement disorders

Behavioral and movement disorders may have antibody responses where mimicry and signal transduction may lead to neuropsychiatric abnormalities. In our study, antibodies in pediatric autoimmune neuropsychiatric disorders associated with streptococci (PANDAS) reacted with the neuronal cell surface and caudate-putamen and induced calcium-calmodulin dependent protein (CaM) kinase II activity in neuronal cells. Depletion of serum IgG abrogated CaM kinase II cell signaling and reactivity of CSF was blocked by streptococcal antigen N-acetyl-beta-d-glucosamine (GlcNAc). Antibodies against GlcNAc in PANDAS sera were inhibited by lysoganglioside G(M1). Results suggest that antibodies from an infection may signal neuronal cells in some behavioral and movement disorders.

Activation of humoral immunity and eosinophils in neuromyelitis optica

OBJECTIVE

To study immunologic alterations in patients with neuromyelitis optica (NMO).

METHODS

The authors studied 8 patients with NMO together with 16 healthy subjects, 16 patients with relapsing remitting multiple sclerosis (RRMS), and 16 patients with secondary progressive MS (SPMS), matched for age and sex, as controls. Because recent histopathologic studies have demonstrated that active NMO lesions consist of perivascular immunoglobulin (Ig) deposition and eosinophil infiltration, IL-5, IL-6, IL-12, IgG, and IgM production by anti-myelin oligodendrocyte glycoprotein (MOG) mononuclear cells in peripheral blood and CSF were selected for study using ELISPOT. Eotaxin-2 (Eo-2) and eotaxin-3 (Eo-3) levels were also assessed using ELISA and eosinophil cationic protein (ECP) levels by radioimmunoassay.

RESULTS

MOG-specific responses in CSF showed significant increase in IL-5, IL-6, IgG, and IgM secreting cells in NMO patients compared with patients with RRMS, SPMS and healthy subjects. Interestingly, numbers of IgM secreting cells were significantly higher than identical specificity IgG secreting ones. Moreover, CSF Eo-2, Eo-3, and ECP levels were also significantly higher in NMO patients compared to all three control populations. Anti-MOG IL-12 secreting cells were increased in CSF and peripheral blood from NMO, RRMS, and SPMS patients when compared to healthy subjects.

CONCLUSIONS

These observations suggest that neuromyelitis optica is associated with a major humoral immune response (particularly anti-MOG IgM production) and eosinophil activation present exclusively in CSF.

Anti-MOG autoantibodies in Italian multiple sclerosis patients: specificity, sensitivity and clinical association

There is considerable evidence that multiple sclerosis (MS) is an immune-mediated disease characterized by infiltration of inflammatory cells into the CNS and demyelination. Several myelin proteins may be encephalitogenic, including myelin basic protein, proteolipid protein and myelin oligodendrocyte glycoprotein (MOG), the latter being expressed on the external layer of myelin sheaths and hence accessible to antibody attack. We investigated MOG autoreactivity in serum and cerebrospinal fluid (CSF) by ELISA, employing the recombinant extracellular domain of MOG as antigen. We tested serum samples from 262 MS patients (175 relapsing-remitting, 43 primary progressive and 44 secondary progressive), 131 patients with other neurological diseases (OND) and 307 healthy controls. No patients or controls were receiving immunomodulating treatments. We found anti-MOG antibodies in the serum of 13.7% MS patients, mainly in those with secondary progressive MS (25%), in 13.7% of OND patients and in 6.2% of controls. We found a direct correlation (R(2) = 0.6, P = 0.002) between disease severity and anti-MOG titer only in patients with primary and secondary progressive MS. Anti-MOG antibodies were present in the CSF of 11.4% MS patients and 18.9% OND patients. Intrathecal synthesis of anti-MOG antibodies was demonstrated in four (4.5%) of MS patients and no OND patients. Anti-MOG antibodies are not specific for MS; however, they may characterize a subset of MS patients and this may be revealed by serial assays in relation to changing disease phase.

Idiopathic autonomic neuropathy: comparison of cases seropositive and seronegative for ganglionic acetylcholine receptor antibody

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.

Prevalence of serum antibodies to caudate nucleus in autistic children

Autism may involve autoimmunity to brain. We studied regional distribution of antibodies to rat caudate nucleus, cerebral cortex, cerebellum, brain stem and hippocampus. The study included 30 normal and 68 autistic children. Antibodies were assayed by immunoblotting. Autistic children, but not normal children, had antibodies to caudate nucleus (49% positive sera), cerebral cortex (18% positive sera) and cerebellum (9% positive sera). Brain stem and hippocampus were negative. Antibodies to caudate nucleus were directed towards three proteins having 160, 115 and 49 kD molecular weights. Since a significant number of autistic children had antibodies to caudate nucleus, we propose that an autoimmune reaction to this brain region may cause neurological impairments in autistic children. Thus, the caudate nucleus might be involved in the neurobiology of autism.

Side effects of intravenous immunoglobulins in neurological autoimmune disorders--a prospective study

The increased use of intravenous immunoglobulins (IVIg) in the treatment of neurological autoimmune diseases has led to more awareness of adverse reactions. We studied prospectively the side effects of IVIg during 84 treatment courses with a total of 341 infusions under routine clinical conditions. Mild reactions were common. Headache was noted most often, occurring during 30% of treatment courses. There were three severe adverse events (3.6% of all treatment courses) that led to discontinuation of the treatment, namely thrombosis of the jugular vein, allergic reaction and retrosternal pressure. Significant changes in laboratory findings were seen for leucocytes, erythrocytes, haematocrit, haemoglobin, ALAT and ASAT. None of these changes were clinically relevant. The elevation of liver enzymes was dependent on the IVIg preparation used, while there was no association with the underlying disease, age, or gender of the patient. In conclusion, this prospective study confirms the high frequency of mild, self-limited side effects of IVIg. Elevation of liver enzymes may possibly be associated with certain IVIg preparations. Bearing these complications in mind, this prospective study supports the notion that IVIg can generally be regarded as safe, leading to severe adverse events during only 3 (0.9%) of 341 infusions (or 3 of 84 treatment courses, 3.6 %). However, careful monitoring for severe side effects remains mandatory, and we propose that laboratory findings like full blood count, renal and liver function should be monitored routinely.

Tourette's syndrome: a cross sectional study to examine the PANDAS hypothesis

BACKGROUND

The classical neurological disorder after group A beta haemolytic streptococcal infection is Sydenham's chorea. Recently a tic disorder occurring after group A streptococcal infection has been described and termed PANDAS (paediatric autoimmune neuropsychiatric disorders associated with streptococcal infection). It is proposed that antibodies induced after group A streptococcal infection react with basal ganglia neurones in Sydenham's chorea and PANDAS. Anti-basal ganglia antibodies (ABGA) are present in most cases of acute Sydenham's chorea, but rarely in controls.

OBJECTIVE

To investigate the hypothesis that Tourette's syndrome may be associated with group A streptococcal infection and ABGA.

METHODS

100 patients with Tourette's syndrome (DSM-IV-TR) were enrolled in a cross sectional study. Children with neurological disease (n = 50) and recent uncomplicated streptococcal infection (n = 40), adults with neurological disease (n = 50), and healthy adults (n = 50) were studied as controls. Recent group A streptococcal infection was defined using antistreptolysin O titre (ASOT). ABGA were detected using western immunoblotting and indirect immunofluorescence.

RESULTS

ASOT was raised in 64% of children with Tourette's syndrome compared with 15% of paediatric neurological disease controls (p < 0.0001), and in 68% of adults with Tourette's syndrome compared with 12% of adult neurological controls and 8% of adult healthy controls (p < 0.05). Western immunoblotting showed positive binding in 20% of children and 27% of adults with Tourette's syndrome, compared with 2-4% of control groups (p < 0.05). The most common basal ganglia binding was to a 60 kDa antigen, similar to the proposed antigen in Sydenham's chorea. Indirect immunofluorescence revealed autoantibody binding to basal ganglia neurones. Serological evidence of recent group A streptococcal infection, assessed by a raised ASOT, was detected in 91% (21/23) of Tourette's syndrome patients with positive ABGA compared with 57% (44/77) with negative ABGA (p < 0.01).

CONCLUSIONS

The results support a role of group A streptococcal infection and basal ganglia autoimmunity in a subgroup of patients with Tourette's syndrome and suggest a pathogenic similarity between Sydenham's chorea and some patients with Tourette's syndrome.

CSF and serum immune parameters in Sydenham's chorea: evidence of an autoimmune syndrome?

Previous investigations have suggested that Sydenham's chorea (SC) may be an autoantibody mediated disorder. We examined this autoimmune hypothesis by measuring Th1 (IFN-gamma, IL-12) and Th2 (IL-4, IL-10) cytokines, oligoclonal bands (OCB) and anti-basal ganglia antibodies (ABGA). CSF IL-4 was elevated in 31% of acute SC and 50% of persistent SC. CSF IL-10 was also elevated in 31% of acute SC but 0% of persistent SC. CSF IFN-gamma was undetectable in all patients. Serums IL-4, IL-10 and IL-12 were elevated in acute compared to persistent SC. OCB were found in 46% of acute SC, ABGA were in 93% of acute SC and 50% of persistent SC was of IgG(1) and IgG(3) subclass. These findings support an autoantibody pathogenesis.

Anti-basal ganglia antibody abnormalities in Sydenham chorea

Anti-basal ganglia antibodies (ABGA) were measured in nine children with Sydenham chorea (SC) and compared to nine controls. Enzyme-linked immunosorbent assay (ELISA) and Western blot (WB) methods were used to detect ABGA against supernatant (S1), pellet, and synaptosomal preparations from adult and pediatric postmortem caudate, putamen, and globus pallidus. ELISA optical density (OD) values were higher in SC patients than controls across all preparations, but did not reach a level of significance. Although WB identified multiple bands in all subjects, discriminant analysis showed that the mean binding patterns of SC patients were significantly different from control, most notably in the caudate S1 fraction (Wilks' lambda=0.011, p<0.0001). Numerous antigens contributed to differences between groups; the two most defining molecular masses were at 126 and 113 kDa. In contrast to WB with discriminant analysis, ELISA measurements did not significantly differentiate between the SC group and controls.

Antibodies to neuron-specific antigens in children with autism: possible cross-reaction with encephalitogenic proteins from milk, Chlamydia pneumoniae and Streptococcus group A

We measured autoantibodies against nine different neuron-specific antigens and three cross-reactive peptides in the sera of autistic subjects and healthy controls by means of enzyme-linked immunosorbent assay (ELISA) testing. The antigens were myelin basic protein (MBP), myelin-associated glycoprotein (MAG), ganglioside (GM1), sulfatide (SULF), chondroitin sulfate (CONSO4), myelin oligodendrocyte glycoprotein (MOG), alpha,beta-crystallin (alpha,beta-CRYS), neurofilament proteins (NAFP), tubulin and three cross-reactive peptides, Chlamydia pneumoniae (CPP), streptococcal M protein (STM6P) and milk butyrophilin (BTN). Autistic children showed the highest levels of IgG, IgM and IgA antibodies against all neurologic antigens as well as the three cross-reactive peptides. These antibodies are specific because immune absorption demonstrated that only neuron-specific antigens or their cross-reactive epitopes could significantly reduce antibody levels. These antibodies may have been synthesized as a result of an alteration in the blood-brain barrier. This barrier promotes access of preexisting T-cells and central nervous system antigens to immunocompetent cells, which may start a vicious cycle. These results suggest a mechanism by which bacterial infections and milk antigens may modulate autoimmune responses in autism.

Neurological disease-associated autoantibodies against an unknown protein encoded by a RES4-22 homologous gene

Screening a human small intestinal library with human serum yielded a clone which encoded a protein res4-22 the gene of which was highly homologous to a recently described gene located in the Huntington's disease locus. Autoantibodies against res4-22 (anti-res4-22), mainly of the immunoglobulin (Ig)A type, were detected in patients with neurological disorders at a higher frequency (18.4%) than in healthy blood donors (8.0%). In neurological patients with cerebral ischaemia anti-res4-22 was found significantly more often (47.4%) than in the total group of neurological patients. Anti-res4-22 positive sera showed significantly more frequently myelin staining in cerebellum and nerve sections than anti-res4-22 negative sera. Our findings demonstrate a new species of human autoantibodies against a newly described protein the function of which is still unknown.

Ganglioside agglutination immunoassay for rapid detection of autoantibodies in immune-mediated neuropathy

Elevated levels of serum autoantibodies directed against gangliosides are closely associated with acute and chronic autoimmune neuropathies. An agglutination immunoassay using polystyrene microparticles coated with a total extract of brain gangliosides was used to test patient sera for the presence of anti-ganglioside antibodies. Results were compared with those obtained by ELISA for anti-GM1 and anti-GQ1b ganglioside antibodies. Eight of the twelve sera from patients with multifocal motor neuropathy and seven of the thirteen sera from patients with Guillain-Barré syndrome were positive for the presence of anti-ganglioside antibodies by the ganglioside agglutination immunoassay. The assay compared favorably with the ELISA system in sensitivity and specificity, while requiring a fraction of the time and cost to perform. The new assay can serve as a rapid and effective method for detecting or screening for anti-ganglioside antibodies in patients with acute or chronic immune-mediated neuropathies. It would be particularly useful for detecting antibodies that react with multiple gangliosides, or with minor or as yet uncharacterized gangliosides.

[Epilepsy, disturbances of behavior and consciousness in presence of normal thyroxine levels: still, consider the thyroid gland]

Three patients, one man aged 51 years, and two women aged 49 and 52 years, had severe fluctuating and progressive neurological and psychiatric symptoms. All three had normal thyroxine levels but elevated thyroid stimulating hormone levels and positive thyroid antibodies. Based on clinical, laboratory, MRI and EEG findings they were eventually diagnosed with Hashimoto's encephalopathy, associated with Hashimoto thyroiditis. Treatment with prednisone in addition to thyroxine suppletion resulted in a remarkable remission of their neuropsychiatric symptoms. The disease is probably under-recognized.