Autoantibodies in postinfectious acute cerebellar ataxia

Treatment Options for Epstein-Barr Virus-Related Disorders of the Central Nervous System

Epstein-Barr virus (EBV), a causative agent for several types of lymphomas and mucosal cancers, is a human lymphotropic herpesvirus with the capacity to establish lifelong latent infection. More than 90% of the human population worldwide is infected. The primary infection is usually asymptomatic in childhood, whereas infectious mononucleosis (IM) is common when the infection occurs in adolescence. Primary EBV infection, with or without IM, or reactivation of latent infection in immunocompromised individuals have been associated with a wide range of neurologic conditions, such as encephalitis, meningitis, acute disseminated encephalomyelitis, and cerebellitis. EBV is also involved in malignant lymphomas in the brain. An increasing number of reports on EBV-related disorders of the central nervous system (CNS) including the convincing association with multiple sclerosis (MS) have put in focus EBV-related conditions beyond its established link to malignancies. In this review, we present the clinical manifestations of EBV-related CNS-disorders, put them in the context of known EBV biology and focus on available treatment options and future therapeutic approaches.

Post-Infectious Acute Cerebellar Ataxia Treatment, a Case Report and Review of Literature

Background: infectious mononucleosis is very common during childhood and neurological manifestations are extremely rare. However, when they occur, an appropriate treatment must be undertaken to reduce morbidity and mortality as well as to ensure appropriate management. Methods: we describe the clinical and neurological records of a female patient with post-EBV acute cerebellar ataxia, whose symptoms rapidly resolved with intravenous immunoglobulin therapy. Afterwards, we compared our results with published data. Results: we reported the case of an adolescent female with a 5-day history of sudden asthenia, vomiting, dizziness, and dehydration, with a positive monospot test and hypertransaminasemia. In the following days, she developed acute ataxia, drowsiness, vertigo, and nystagmus with a positive EBV IgM titer, confirming acute infectious mononucleosis. The patient was clinically diagnosed with EBV-associated acute cerebellitis. A brain MRI showed no acute changes and a CT scan showed hepatosplenomegaly. She started therapy with acyclovir and dexamethasone. After a few days, because of her condition’s deterioration, she received intravenous immunoglobulin and demonstrated a good clinical response. Conclusions: although there are no consensus guidelines for the treatment of post-infectious acute cerebellar ataxia, early intervention with intravenous immunoglobulin might prevent adverse outcomes, especially in cases that do not respond to high-dose steroid therapy.

Anti-SOX1 Antibodies in a 3-Year-old Girl, Post-Varicella

Anti-SRY-related HMG-box gene 1 (SOX1) antibodies were initially described in adults with paraneoplastic neurological disorders, where they are considered high-risk onconeural autoantibodies. Only two pediatric cases of anti-SOX1 antibodies have been reported: a 17-year-old adolescent presenting with paraneoplastic limbic encephalitis due to Hodgkin lymphoma and a 12-year-old girl presenting with non-paraneoplastic encephalitis. We present a unique case of anti-SOX1 antibodies in a 3-year-old girl, post-varicella infection. Initially, she presented with ataxia and dysmetria, with subsequent reports from parents of urinary incontinence and significant behavior changes. Additionally, reflexes in the lower limbs were absent. Anti-SOX1 antibodies tested positive in both serum and cerebrospinal fluid. Oncological screening at presentation and a seven-month follow-up showed no malignancies. The patient exhibited favorable clinical progress without requiring treatment. At the seven-month follow-up, serum antibodies tested negative. This case report broadens the known clinical spectrum, being the first description of post-varicella anti-SOX1 antibodies.

A Breakdown of Immune Tolerance in the Cerebellum

Cerebellar dysfunction can be associated with ataxia, dysarthria, dysmetria, nystagmus and cognitive deficits. While cerebellar dysfunction can be caused by vascular, traumatic, metabolic, genetic, inflammatory, infectious, and neoplastic events, the cerebellum is also a frequent target of autoimmune attacks. The underlying cause for this vulnerability is unclear, but it may be a result of region-specific differences in blood–brain barrier permeability, the high concentration of neurons in the cerebellum and the presence of autoantigens on Purkinje cells. An autoimmune response targeting the cerebellum—or any structure in the CNS—is typically accompanied by an influx of peripheral immune cells to the brain. Under healthy conditions, the brain is protected from the periphery by the blood–brain barrier, blood–CSF barrier, and blood–leptomeningeal barrier. Entry of immune cells to the brain for immune surveillance occurs only at the blood-CSF barrier and is strictly controlled. A breakdown in the barrier permeability allows peripheral immune cells uncontrolled access to the CNS. Often—particularly in infectious diseases—the autoimmune response develops because of molecular mimicry between the trigger and a host protein. In this review, we discuss the immune surveillance of the CNS in health and disease and also discuss specific examples of autoimmunity affecting the cerebellum.

A Case of Influenza Virus-Induced Acute Cerebellitis Treated with Steroid Pulse Therapy

Acute cerebellitis (AC) is characterized by acute onset cerebellar ataxia brain magnetic resonance imaging (MRI) abnormalities of the cerebellum. The most common cause of AC is viral infection, and some patients with AC experience neurological sequelae. AC associated with influenza virus is extremely rare, and its prognosis and treatment are unknown. We present the case of a 2-year-old boy with influenza virus-induced AC who was treated with pulse steroid therapy. The patient presented with fever, anorexia, vomiting, malaise, altered consciousness, truncal ataxia, dysmetria, and dysarthria. He was diagnosed with influenza using a nasopharyngeal antigen test. Brain MRI showed hyperintense T2 and diffusion-weighted signal abnormalities in the cerebellar white matter and dentate nuclei bilaterally. The patient was treated with two courses of pulse methylprednisolone therapy and recovered completely in 2 months after the onset. The prognosis of AC is poorer than that of acute cerebellar ataxia, which shows similar symptoms to AC with normal brain MRI. The type of virus might also be associated with the prognosis of AC. Literature review showed that one of the five cases (including the present case, 20%) reported with influenza-associated AC was noted to have neurological sequelae, which might be more severe than those of varicella-zoster-related AC. Given that the pathogenesis of AC is assumed to be immune-mediated, pulse methylprednisolone therapy might be a good option for the treatment of influenza virus-induced AC.

Intravenous immunoglobulins in an adult case of post-EBV cerebellitis

Post-Epstein-Barr virus (EBV) cerebellitis is very rare complication of infectious mononucleosis and only a few adult cases are reported in literature. We present a 23-year-old patient who was admitted to the neurology service with worsening ataxia, nystagmus and dysarthria, 1 week after infectious mononucleosis. Imaging and cerebrospinal fluid studies were normal, serum studies revealed acute transaminitis and positive EBV viral capsid IgM and IgG. The patient underwent a 5-day course of intravenous immunoglobulins with rapid resolution of all his symptoms and was safely discharged home. The pathophysiology of post-EBV cerebellitis involves autoreactive antibodies, rather than a direct viral insult. Antineuronal antibodies might be the result of a mimicry between EBV proteins and neuronal antigens or they can be secreted by the EBV-transformed lymphocytes themselves. Many reports stress the benign, self-limiting nature of this syndrome; however, immunotherapy might de facto decrease the severity and duration of illness.

Intravenous Immunoglobulin: A Good Choice for Acute Cerebellar Ataxia Associated with Varicella

Postinfectious cerebellar ataxia is the most common cause of acute ataxia in childhood. The most frequently associated viral agent is varicella. Acute cerebellar ataxia is considered benign, and its symptoms usually diminish within several weeks. We describe a 5-year-old boy who developed gait disorder and garble speech 2 weeks after chicken pox and who was successfully treated with intravenous immunoglobulin.

Acute cerebellitis in children: an eleven year retrospective multicentric study in Italy

Background

Acute cerebellitis (AC) and acute cerebellar ataxia (ACA) are the principal causes of acute cerebellar dysfunction in childhood. Nevertheless. there is no accepted consensus regarding the best management of children with AC/ACA: the aim of the study is both to assess clinical, neuroimaging and electrophysiologic features of children with AC/ACA and to evaluate the correlation between clinical parameters, therapy and outcome.

Methods

A multicentric retrospective study was conducted on children ≤ 18 years old admitted to 12 Italian paediatric hospitals for AC/ACA from 01/01/2003 to 31/12/2013. A score based on both cerebellar and extracerebellar signs/symptoms was computed for each patient. One point was given for each sign/symptom reported. Severity was divided in three classes: low, moderate, severe.

Results

A total of 124 children were included in the study. Of these, 118 children received a final diagnosis of ACA and 6 of AC. The most characteristic finding of AC/ACA was a broad-based gait disturbance. Other common symptoms included balance disturbances, slurred speech, vomiting, headache and fever. Neurological sequelae were reported in 6 cases (5%) There was no correlation among symptoms, cerebrospinal fluid findings, clinical outcome. There was no correlation between clinical manifestations and clinical score on admission and length of hospital stay, sex, age and EEG findings with sequelae (P > 0.05).

Children with pathological magnetic resonance imaging (MRI) or computed tomography (CT) had a higher probability of having clinical sequelae.

Treatment was decided independently case by case. Patients with a higher clinical score on admission had a higher probability of receiving intravenous steroids.

Conclusions

We confirmed the literature data about the benign course of AC/ACA in most cases but we also highlighted a considerable rate of patients with neurological sequelae (5%). Pathological MRI or CT findings at admission correlate to neurological sequelae. These findings suggest the indication to perform an instrumental evaluation in all patients with AC/ACA at admission to identify those at higher risk of neurological outcome. These patients may benefit from a more aggressive therapeutic strategy and should have a closer follow-up. Randomized controlled trials are needed to confirm these observations. The ultimate goal of these studies could be to develop a standardized protocol on AC/ACA. The MRI/CT data, associated with the clinical manifestations, may allow us to define the class risk of patients for a neurological outcome.

Acute Ataxia in Children: A Review of the Differential Diagnosis and Evaluation in the Emergency Department

Acute ataxia in a pediatric patient poses a diagnostic dilemma for any physician. While the most common etiologies are benign, occasional individuals require urgent intervention. Children with stroke, toxic ingestion, infection, and neuro-inflammatory disorders frequently exhibit ataxia as an essential-if not the only-presenting feature. The available retrospective research utilize inconsistent definitions of acute ataxia, precluding the ability to pool data from these studies. No prospective data exist that report on patients presenting to the emergency department with ataxia. This review examines the reported causes of ataxia and attempts to group them into distinct categories: post-infectious and inflammatory central and peripheral phenomena, toxic ingestion, neurovascular, infectious and miscellaneous. From there, we synthesize the existing literature to understand which aspects of the history, physical exam, and ancillary testing might aid in narrowing the differential diagnosis. MRI is superior to CT in detecting inflammatory or vascular insults in the posterior fossa, though CT may be necessary in emergent situations. Lumbar puncture may be deferred until after admission in most instances, with suspicion for meningitis being the major exception. There is insufficient evidence to guide laboratory evaluation of serum, testing should be ordered based on clinical judgement-recommended studies include metabolic profiles and screening labs for metabolic disorders (lactate and ammonia). All patients should be reflexively screened for toxic ingestions.

Barr humbug: acute cerebellar ataxia due to Epstein-Barr virus

Epstein-Barr virus (EBV) infection is associated with neurological sequellae, but rarely there is acute cerebellar ataxia (ACA) in an adult. We present a novel case of a 26-year-old man, who presented with ACA. He had normal MRI and CSF analysis. Serum testing confirmed active EBV. A course of oral prednisolone 1 mg/kg for 4 weeks, with a subsequent taper was started. He made a full recovery within 3 weeks of presentation.

Acute Ataxia in Childhood: 11-Year Experience at a Major Pediatric Neurology Referral Center

We categorized the causes of acute ataxia in the pediatric population-referred to the Division of Neurology-at a large, urban pediatric medical center. Of the 120 cases identified over the past 11 years, post-infectious cerebellar ataxia was the most commonly diagnosed (59%), followed by drug intoxication, opsoclonus-myoclonus ataxia syndrome, episodic ataxia, acute cerebellitis, cerebellar stroke, ADEM, meningitis, cerebral vein thrombosis, Leigh's disease, Miller-Fisher syndrome, and concussion. Among the patients with post-infectious cerebellar ataxia, 85% were 1-6 years old and all had a history of antecedent viral illness. CSF pleocytosis was present in 40% of patients; all had normal brain MRIs. The majority (91%) recovered within 30 days. We conclude that post-infectious cerebellar ataxia remains the most common cause of acute ataxia in childhood and that it carries a good prognosis. We also differentiate acute post-infectious cerebellar ataxia from other causes with similar presentations.

Acute Cerebellar Ataxia: An Unusual Pediatric Case

BACKGROUND

Acute cerebellar ataxia is a clinical syndrome with sudden onset of uncoordinated gait and normal mental status in young children. Although it has a benign clinical course, it often requires an exhaustive diagnostic work-up in order to rule out potentially life-threatening etiologies that present similarly. The wide differential encompasses causes from infections, brain masses, drugs, toxins, trauma, paraneoplastic syndromes, as well as hereditary or congenital disorders.

CASE REPORT

We report on a 4-year-old boy with recent hand-foot-mouth disease who presented with acute cerebellar ataxia. In addition to his marked truncal ataxia and wide-based, staggering gait, he had slowness of speech, which is not commonly reported with this condition in the literature. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Emergency physicians have a unique role in being first to evaluate pediatric ataxia and can make a significant impact on identifying potentially fatal mimickers of acute cerebellar ataxia. This article will attempt to outline major diagnostic considerations in order to aid emergency physicians through their clinical approach.

'Medusa-head ataxia': the expanding spectrum of Purkinje cell antibodies in autoimmune cerebellar ataxia. Part 1: Anti-mGluR1, anti-Homer-3, anti-Sj/ITPR1 and anti-CARP VIII

Serological testing for anti-neural autoantibodies is important in patients presenting with idiopathic cerebellar ataxia, since these autoantibodies may indicate cancer, determine treatment and predict prognosis. While some of them target nuclear antigens present in all or most CNS neurons (e.g. anti-Hu, anti-Ri), others more specifically target antigens present in the cytoplasm or plasma membrane of Purkinje cells (PC). In this series of articles, we provide a detailed review of the clinical and paraclinical features, oncological, therapeutic and prognostic implications, pathogenetic relevance, and differential laboratory diagnosis of the 12 most common PC autoantibodies (often referred to as 'Medusa-head antibodies' due to their characteristic somatodendritic binding pattern when tested by immunohistochemistry). To assist immunologists and neurologists in diagnosing these disorders, typical high-resolution immunohistochemical images of all 12 reactivities are presented, diagnostic pitfalls discussed and all currently available assays reviewed. Of note, most of these antibodies target antigens involved in the mGluR1/calcium pathway essential for PC function and survival. Many of the antigens also play a role in spinocerebellar ataxia. Part 1 focuses on anti-metabotropic glutamate receptor 1-, anti-Homer protein homolog 3-, anti-Sj/inositol 1,4,5-trisphosphate receptor- and anti-carbonic anhydrase-related protein VIII-associated autoimmune cerebellar ataxia (ACA); part 2 covers anti-protein kinase C gamma-, anti-glutamate receptor delta-2-, anti-Ca/RhoGTPase-activating protein 26- and anti-voltage-gated calcium channel-associated ACA; and part 3 reviews the current knowledge on anti-Tr/delta notch-like epidermal growth factor-related receptor-, anti-Nb/AP3B2-, anti-Yo/cerebellar degeneration-related protein 2- and Purkinje cell antibody 2-associated ACA, discusses differential diagnostic aspects and provides a summary and outlook.

'Medusa head ataxia': the expanding spectrum of Purkinje cell antibodies in autoimmune cerebellar ataxia. Part 3: Anti-Yo/CDR2, anti-Nb/AP3B2, PCA-2, anti-Tr/DNER, other antibodies, diagnostic pitfalls, summary and outlook

Serological testing for anti-neural autoantibodies is important in patients presenting with idiopathic cerebellar ataxia, since these autoantibodies may indicate cancer, determine treatment and predict prognosis. While some of them target nuclear antigens present in all or most CNS neurons (e.g. anti-Hu, anti-Ri), others more specifically target antigens present in the cytoplasm or plasma membrane of Purkinje cells (PC). In this series of articles, we provide a detailed review of the clinical and paraclinical features, oncological, therapeutic and prognostic implications, pathogenetic relevance, and differential laboratory diagnosis of the 12 most common PC autoantibodies (often referred to as 'Medusa head antibodies' due to their characteristic somatodendritic binding pattern when tested by immunohistochemistry). To assist immunologists and neurologists in diagnosing these disorders, typical high-resolution immunohistochemical images of all 12 reactivities are presented, diagnostic pitfalls discussed and all currently available assays reviewed. Of note, most of these antibodies target antigens involved in the mGluR1/calcium pathway essential for PC function and survival. Many of the antigens also play a role in spinocerebellar ataxia. Part 1 focuses on anti-metabotropic glutamate receptor 1-, anti-Homer protein homolog 3-, anti-Sj/inositol 1,4,5-trisphosphate receptor- and anti-carbonic anhydrase-related protein VIII-associated autoimmune cerebellar ataxia (ACA); part 2 covers anti-protein kinase C gamma-, anti-glutamate receptor delta-2-, anti-Ca/RhoGTPase-activating protein 26- and anti-voltage-gated calcium channel-associated ACA; and part 3 reviews the current knowledge on anti-Tr/delta notch-like epidermal growth factor-related receptor-, anti-Nb/AP3B2-, anti-Yo/cerebellar degeneration-related protein 2- and Purkinje cell antibody 2-associated ACA, discusses differential diagnostic aspects and provides a summary and outlook.

Acute hemicerebellitis in a young adult: a case report and literature review

Acute hemicerebellitis, marked by headache with or without cerebellar signs, is a rare clinical entity involving a unilateral cerebellar hemisphere. The pathogenesis of acute hemicerebellitis remains unclear, and the disease rarely occurs in adults. Here, we report an 18-year-old woman who presented with a lack of coordination of the right hand and leg lasting longer than one week, following a pulsatile headache. A neurological examination disclosed ocular dysmetria, right-sided limb ataxia and slight truncal ataxia. Cerebrospinal fluid analysis showed mononuclear pleocytosis. The serology and autoimmune studies were unremarkable. Brain magnetic resonance imaging (MRI) revealed a focal signal change in the right cerebellar hemisphere and vermis. Acute hemicerebellitis was diagnosed, and the patient was treated with intravenous methylprednisolone sodium succinate and acyclovir. Subsequently, the headache resolved, and the cerebellar signs were markedly improved. Twenty days after admission, she became asymptomatic and brain MRI showed resolution of cerebellar hyperintensity on the right side. In conclusion, we identified only 6 additional patients with adult-onset acute hemicerebellitis from previous reports, highlighting the importance of recognizing this rare clinical entity. Its clinical outcome is usually favorable, but in the acute phase, attention should be directed toward clinical symptoms that are suggestive of increased intracranial pressure.

Acute post-infectious cerebellar ataxia due to co-infection of human herpesvirus-6 and adenovirus mimicking myositis

Acute cerebellar ataxia (ACA) is a relatively common neurological disease in children. Most common types of ACA are acute post-infectious (APCA) and acute disseminated encephalomyelitis (ADEM). Less common but important causes include opsoclonus-myoclonus syndrome (OMS) and acute cerebellitis. Cerebellar neoplasms and acute hydrocephalus are additional causes of paediatric ataxia. APCA is the most common cause of ACA in children, comprising about 30-50% of total cases. This is a report about an immunocompetent 4-yrs-old male affected by APCA, due to co-infection by human herpesvirus-6 (HHV-6) and adenovirus, with symptoms mimicking myositis.

Acute cerebellitis in varicella: a ten year case series and systematic review of the literature

Background

Acute cerebellitis (AC) is the most common neurological complication of varicella. Nevertheless, it has been scarcely studied. The objective of this study were to asses the occurrence of AC among children hospitalized for varicella and to analyze its specific clinical picture and outcome.

Methods

We retrospectively reviewed the medical records of children admitted to the hospital for varicella between 1^st October 2003 and 1^st June 2013 and we compared our results with literature. Children were all unvaccinated for varicella.

Results

In our case series, AC was found out in 48 out of 457 patients (10.5%). The highest frequency of AC was observed in children from 1 to 5 years of age (60.9%). The most characteristic symptom of AC was a broad-based gait disturbance that progressed gradually over the course of a few days (95.8%). Other common symptoms included slurred speech (37.5%), vomiting (31.25%), headache (29.16%), dysmetry (25%) and tremor (22.91%). After a long hospitalization (median of 11 days), all but one children were dismissed without invalidating sequelae.

Conclusions

Data from this study may help to better address the problem of varicella cerebellar complications in hospitalized children and to monitor changes over time caused by an increase in vaccination coverage.

Case report of subacute cerebellar ataxia of adolescence with long-term sequelae

Acute ataxia is not an uncommon childhood complaint. It most commonly occurs in young patients secondary to a postinfectious cerebellitis, which is typically associated with a very good prognosis and recovery. In adolescence, acute cerebellar ataxia is more often the product of an etiology likely to progress into a chronic disorder without recovery to preillness baseline. In the present case, the authors describe a 15-year-old girl with subacute cerebellar ataxia of presumed immune-mediated etiology that advanced into a chronic cerebellar ataxia. Due to a family history, celiac disease was suspected as the origin of the ataxia; biopsy ruled out enteropathy, and the severe, abrupt radiological changes to the patient's cerebellum are inconsistent with the reported sequelae of gluten ataxia. This case serves as a discussion for diagnostic challenges in adolescent patients with acute cerebellar ataxia with long-term sequelae as well as providing an adjunct discussion on the neurological complications of celiac disease.

Acute hemicerebellitis in children: case report and review of literature

Acute hemicerebellitis in childhood is an extremely rare unilateral presentation of cerebellitis mimicking a tumour. Its aetiology is unknown, although an inflammatory or postinfectious origin is presumed. Its clinical outcome is generally good and a self-limited evolution, in the absence of specific treatment, is usually expected. MRI findings can be misunderstood leading to erroneous diagnosis and invasive treatments. Clinical improvement and regression of the pathological findings in serial MRI will help differentiate acute hemicerebellitis from a neoplastic process. Surgical procedures should be performed only in case of clinical deterioration. We present a case of pseudotumoral hemicerebellitis in an eight-year-old girl, presenting with severe headache. This paper provides a review on hemicerebellitis and highlights the clinical, diagnostic, therapeutic features and outcome of this entity.

Role of BAFF in Opsoclonus-Myoclonus syndrome, a bridge between cancer and autoimmunity

OMS is a rare paraneoplastic disorder that affects adults and children. Pediatric OMS is often associated with NB, a common, solid tumor of childhood, derived from the sympathetic nervous system. The detection of autoantibodies and lymphocytic infiltration in NB patients led to advance an autoimmune hypothesis for the pathogenesis of OMS-related NB. BAFF is a potent modulator of B cell growth and survival upon interaction with its receptors BAFF-R and BCMA. The aim of this study was to investigate mechanism(s) involved in ectopic lymphoid neogenesis in OMS-associated NB. We investigated BAFF, BAFF-R, and BCMA expression in NB tumors associated or not with OMS. Furthermore, we evaluated BAFF expression and secretion in NB cell lines, treated or untreated with differentiating agents. Immunohistochemically, lymphocytes infiltrating NB tumors from patients, with or without OMS, expressed BAFF, BAFF-R, and BCMA, whereas neuroblasts expressed BAFF and BCMA but not BAFF-R. By flow cytometry, BAFF was found to be consistently expressed in NB cell lines. Similarly to the results obtained in tissue lesions, BCMA but not BAFF-R was detected on the surface of all NB cell lines under basal conditions. De novo synthesis of BAFF-R and up-regulation of BCMA were observed in NB cell lines upon treatment with IFN-γ or 13-cis retinoic acid. This study provides new insights in the mechanisms driving the neogenesis of lymphoid follicles and in the functional interactions between tumor and immune cells in OMS-associated NB.

[A case of chronic active Epstein-Barr virus infection associated with recurrent cerebellar ataxia and skin eruptions]

A 62-year-old woman presented with subacute cerebellar ataxia, lymph node swelling and skin eruption. Laboratory tests revealed elevated titers of anti-VCA-IgG antibody and anti-EADR-IgG antibody, with Epstein-Barr virus (EBV) DNA detected from the blood and CSF by PCR. Since these data were highlighted with the diagnosis of chronic active EBV infection (CAEBV) and her ataxia improved concomitantly with the remission of other infectious mononucleosis-like symptoms, we supposed her ataxia is associated with CAEBV. Five years later, at the age of 67, her ataxia relapsed concurrently with skin eruptions, whereas MRI demonstrated progression of cerebellar atrophy. After high-dose intravenous methylprednisolone treatment, the clinical symptoms resolved. Initial infection of EBV in childhood often causes autoimmune acute cerebellitis but cerebellar ataxia has rarely been described in CAEBV. Furthermore, immunohistochemical analysis revealed a reactivity of the patient's serum and CSF on rat cerebellum, suggesting an autoimmune pathomechanism for the ataxia.

Immunoproteomic identification of immunogenic proteins in Cronobacter sakazakii strain BAA-894

Cronobacter spp. are emerging opportunistic pathogens. Cronobacter sakazakii is considered as the predominant species in all infections. So far, our understanding of the species' immunogens and potential virulence factors of Cronobacter spp. remains limited. In this study, an immunoproteomic approach was used to investigate soluble and insoluble proteins from the genome-sequenced strain C. sakazakii ATCC BAA-894. Proteins were separated using two-dimensional electrophoresis, detected by Western blotting with polyclonal antibodies of C. sakazakii BAA-894, and identified using tandem mass spectrometry (MALDI-MS and MALDI-MS/MS, MS/MSMS). A total of 11 immunoreactive proteins were initially identified in C. sakazakii BAA-894, including two outer membrane proteins, four periplasmic proteins, and five cytoplasmic proteins. In silico functional analysis of the 11 identified proteins indicated three proteins that were initially described as immunogens of pathogenic bacteria. For the remaining eight proteins, one protein was categorized as a potential virulence factor involved in protection against reactive oxygen species, and seven proteins were considered to play potential roles in adhesion, invasion, and biofilm formation. To our knowledge, this is the first time that immunogenic proteins of C. sakazakii BAA-894 have been identified as immunogens and potential virulence factors by an immunoproteomics approach. Future studies should investigate the roles of these proteins in bacterial pathogenesis and modulation of host immune responses during infection to identify their potential as molecular therapeutic targets.

Central nervous system neuronal surface antibody associated syndromes: review and guidelines for recognition

The concept of antibody mediated CNS disorders is relatively recent. The classical CNS paraneoplastic neurological syndromes are thought to be T cell mediated, and the onconeural antibodies merely biomarkers for the presence of the tumour. Thus it was thought that antibodies rarely, if ever, cause CNS disease. Over the past 10 years, identification of autoimmune forms of encephalitis with antibodies against neuronal surface antigens, particularly the voltage gated potassium channel complex proteins or the glutamate N-methyl-D-aspartate receptor, have shown that CNS disorders, often without associated tumours, can be antibody mediated and benefit from immunomodulatory therapies. The clinical spectrum of these diseases is not yet fully explored, there may be others yet to be discovered and some types of more common disorders (eg, epilepsy or psychosis) may prove to have an autoimmune basis. Here, the known conditions associated with neuronal surface antibodies are briefly reviewed, some general aspects of these syndromes are considered and guidelines that could help in the recognition of further disorders are suggested.

Immune-mediated acquired ataxias

The cerebellum, and in particular the Purkinje cells within it, appear to be a frequent immunological target in the context of some systemic diseases. This is perhaps more often the case with the cerebellum by comparison to other structures within the central nervous system. This observation may relate to the fact that the cerebellum is one of the largest, oldest, and most structurally conserved structures in the vertebrate nervous system and/or that Purkinje cells possess good and multiple antigenic targets. Immune-mediated ataxias include paraneoplastic cerebellar degeneration and post-infective cerebellitis, but these will be discussed elsewhere. This chapter covers in detail the epidemiology, clinical characteristics, pathophysiology, and treatment of some other examples of immune-mediated ataxias, including gluten ataxia and ataxia associated with anti-GAD antibodies. There is particular emphasis on gluten ataxia as this is one of the commonest immune-mediated cerebellar ataxias and one of the few ataxias that are potentially treatable. The chapter also introduces the concept of primary autoimmune cerebellar ataxia as a form of organ-specific autoimmune disease for the first time. The pathophysiology leading to cerebellar damage, loss of Purkinje cells, and the development of ataxia remains speculative, but existing clues are discussed in detail.

Inhibition of glyceraldehyde-3-phosphate dehydrogenase activity by antibodies present in the cerebrospinal fluid of patients with multiple sclerosis

We have previously shown that B cells and Abs reactive with GAPDH and antitriosephosphate isomerase (TPI) are present in lesions and cerebrospinal fluid (CSF) in multiple sclerosis (MS). In the current study, we studied the effect of anti-GAPDH and anti-TPI CSF IgG on the glycolytic enzyme activity of GAPDH and TPI after exposure to intrathecal IgG from 10 patients with MS and 34 patients with other neurologic diseases. The degree of inhibition of GAPDH activity by CSF anti-GAPDH IgG in the seven MS samples tested varied from 13 to 98%, which seemed to correlate with the percentage of anti-GAPDH IgG in the CSF IgG (1-45%). Inhibition of GAPDH activity (18 and 23%) by CSF IgG was seen in two of the 34 patients with other neurologic diseases, corresponding to the low percentage of CSF anti-GAPDH IgG (1 and 8%). In addition, depletion of anti-GAPDH IgG from CSF IgG, using immobilized GAPDH, removed the inhibitory effect of the IgG on GAPDH. No inhibition of GAPDH activity was seen with CSF samples not containing anti-GAPDH IgG. No inhibition of TPI activity was seen with any purified CSF IgG sample. These findings demonstrate an increased percentage of anti-GAPDH Abs in the CSF of patients with MS that can inhibit GAPDH glycolytic enzyme activity and may contribute to neuroaxonal degeneration.

[Postvaricella cerebellar ataxia in children in Costa Rica]

INTRODUCTION

Postvaricella cerebellar ataxia (PVCA) and meningoencephalitis are the most common acute neurological complications of chickenpox. The objective of this study was to describe the clinical presentation, management, and outcome of children hospitalized with PVCA in the only pediatric hospital of this developing country, where routine varicella immunization is not yet available.

METHODS

We performed a retrospective chart review of children aged 1-12 years old admitted to the National Children's Hospital of Costa Rica from January 1997 to June 2004 with a diagnosis of PVCA.

RESULTS

Among the 441 immunocompetent patients admitted for varicella zoster virus-associated complications during this period, 37 (8.4%) had PVCA. Twenty-four of the 37 (64.9%) patients were boys. The mean (range) age was 5 (1-10) years. The median (range) interval from rash onset to admission was 2 (1-3) days. Cerebrospinal fluid analysis was available in 22 (59.5%) patients and was normal in all. Head computed tomography showed cerebral edema in six out of 18 patients (33.3%). Intravenous acyclovir was administered to 23 patients but no significant differences in clinical manifestations or outcomes were observed in treated versus untreated patients. The mean (range) length of ataxia was 4 (1-10) days, and seven (19%) patients were still ataxic on discharge. The mean (range) length of hospital stay was 4.4 (2-11) days. Minor sequelae were documented in 13 out of 24 (54.2%) patients during follow-up visits and telephone contacts.

CONCLUSIONS

PVCA is usually associated with a favorable prognosis; however, neurological sequelae can occur. The real utility of acyclovir treatment and brain imaging studies in these children remains controversial.

Acute cerebellar ataxia and consecutive cerebellitis produced by glutamate receptor delta2 autoantibody

Acute cerebellar ataxia is usually a self-limited benign disease, which may develop in children after certain viral infections or vaccinations. There are several reports of acute cerebellar ataxia associated with autoantibodies. Glutamate receptor delta2, a member of the glutamate receptor family, is predominantly expressed in cerebellar Purkinje cells and plays a crucial role in cerebellar functions. To date anti-GluRdelta2 autoantibody was detected in a patient with chronic cerebellitis. Herein, an 18-month-old boy presented with cerebellar ataxia 9 days following a mild respiratory tract infection. Although cerebellar ataxia gradually improved, it worsened yet again following mumps and varicella virus infection. Cerebro-spinal fluid examination and magnetic resonance imaging of the brain demonstrated pleocytosis and meningeal enhancement, respectively. Furthermore, glutamate receptor delta2 autoantibody was detected in serum and cerebro-spinal fluid. Thus, we believe that the glutamate receptor delta2 autoantibody may play a role in cerebellar ataxia and consecutive cerebellitis.