A new Purkinje cell antibody (anti-Ca) associated with subacute cerebellar ataxia: immunological characterization

We report on a newly discovered serum and cerebrospinal fluid (CSF) reactivity to Purkinje cells (PCs) associated with subacute inflammatory cerebellar ataxia. The patient, a previously healthy 33-year-old lady, presented with severe limb and gait ataxia, dysarthria, and diplopia two weeks after she had recovered from a common cold. Immunohistochemical studies on mouse, rat, and monkey brain sections revealed binding of a high-titer (up to 1:10,000) IgG antibody to the cerebellar molecular layer, Purkinje cell (PC) layer, and white matter. The antibody is highly specific for PCs and binds to the cytoplasm as well as to the inner side of the membrane of PC somata, dendrites and axons. It is produced by B cell clones within the CNS, belongs to the IgG1 subclass, and activates complement in vitro. Western blotting of primate cerebellum extract revealed binding of CSF and serum IgG to an 80-97 kDa protein. Extensive control studies were performed to rule out a broad panel of previously described paraneoplastic and non-paraneoplastic antibodies known to be associated with cerebellar ataxia. Screening of >9000 human full length proteins by means of a protein array and additional confirmatory experiments revealed Rho GTPase activating protein 26 (ARHGAP26, GRAF, oligophrenin-1-like protein) as the target antigen. Preadsorption of the patient's serum with human ARHGAP26 but not preadsorption with other proteins resulted in complete loss of PC staining. Our findings suggest a role of autoimmunity against ARHGAP26 in the pathogenesis of subacute inflammatory cerebellar ataxia, and extend the panel of diagnostic markers for this devastating disease

Aquaporin-4 Antibodies Are Not Related to HTLV-1\ud Associated Myelopathy

Introduction: The seroprevalence of human T-cell leukemia virus type 1 (HTLV-1) is very high among Brazilians (,1:200).\ud HTLV-1 associated myelopathy or tropical spastic paraparesis (HAM/TSP) is the most common neurological complication of\ud HTLV-1 infection. HAM/TSP can present with an acute/subacute form of longitudinally extensive myelitis, which can be\ud confused with lesions seen in aquaporin-4 antibody (AQP4-Ab) positive neuromyelitis optica spectrum disorders (NMOSD)\ud on MRI. Moreover, clinical attacks in patients with NMOSD have been shown to be preceded by viral infections in around\ud 30% of cases.\ud Objective: To evaluate the frequency of AQP4-Ab in patients with HAM/TSP. To evaluate the frequency of HTLV-1 infection\ud in patients with NMOSD.\ud Patients and Methods: 23 Brazilian patients with HAM/TSP, 20 asymptomatic HTLV-1+ serostatus patients, and 34 with\ud NMOSD were tested for AQP4-Ab using a standardized recombinant cell based assay. In addition, all patients were tested for\ud HTLV-1 by ELISA and Western blotting.\ud Results: 20/34 NMOSD patients were positive for AQP4-Ab but none of the HAM/TSP patients and none of the\ud asymptomatic HTLV-1 infected individuals. Conversely, all AQP4-Ab-positive NMOSD patients were negative for HTLV-1\ud antibodies. One patient with HAM/TSP developed optic neuritis in addition to subacute LETM; this patient was AQP4-Ab\ud negative as well. Patients were found to be predominantly female and of African descent both in the NMOSD and in the\ud HAM/TSP group; Osame scale and expanded disability status scale scores did not differ significantly between the two\ud groups.\ud Conclusions: Our results argue both against a role of antibodies to AQP4 in the pathogenesis of HAM/TSP and against an\ud association between HTLV-1 infection and the development of AQP4-Ab. Moreover, the absence of HTLV-1 in all patients\ud with NMOSD suggests that HTLV-1 is not a common trigger of acute attacks in patients with AQP4-Ab positive NMOSD in\ud populations with high HTLV-1 seroprevalence.This study received financial support from the Brazilian government agencies FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo - www. fapesp.br/en) and CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - www.capes.gov.br). The work of S.J. and B.W. was supported by research grants from Bayer Schering Healthcare and from Merck Serono. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Contrasting disease patterns in seropositive and seronegative neuromyelitis optica: A multicentre study of 175 patients

BACKGROUND: The diagnostic and pathophysiological relevance of antibodies to aquaporin-4 (AQP4-Ab) in patients with neuromyelitis optica spectrum disorders (NMOSD) has been intensively studied. However, little is known so far about the clinical impact of AQP4-Ab seropositivity. OBJECTIVE: To analyse systematically the clinical and paraclinical features associated with NMO spectrum disorders in Caucasians in a stratified fashion according to the patients' AQP4-Ab serostatus. METHODS: Retrospective study of 175 Caucasian patients (AQP4-Ab positive in 78.3%). RESULTS: Seropositive patients were found to be predominantly female (p 1 myelitis attacks in the first year were identified as possible predictors of a worse outcome. CONCLUSION: This study provides an overview of the clinical and paraclinical features of NMOSD in Caucasians and demonstrates a number of distinct disease characteristics in seropositive and seronegative patients

Transient Generalized Chorea in Influenza A Encephalopathy

Background: Influenza A infections are a rare cause of movement disorders. Previously described patients have suffered from acute-onset myoclonus and/or dystonia or post-viral parkinsonism. Case Report: We present the case of a 74-year-old female patient with transient generalized chorea due to influenza A-mediated encephalopathy. Discussion: We discuss whether the clinical presentation and the magnetic resonance imaging changes may be attributable to cytokine-mediated encephalopathy or to direct cytotoxic effects of the virus. Additionally, we would like to make clinicians aware of this clinical sign in the context of viral encephalopathy

Muscle Cramps and Neuropathies in Patients with Allogeneic Hematopoietic Stem Cell Transplantation and Graft-versus-Host Disease

<div><h3>Objective</h3><p>Graft-versus-host disease (GVHD) is an immune-mediated multisystemic disorder and the leading cause of morbidity after allogeneic hematopoietic stem cell transplantation. Peripheral nervous system manifestations of GVHD are rare but often disabling. Whereas immune-mediated neuropathies are an established feature of GVHD, muscle cramps are not well characterized.</p> <h3>Methods</h3><p>In a single-centre retrospective cohort we studied 27 patients (age 23 to 69 years) with GVHD (acute n = 6, chronic n = 21) who complained of symptoms suggestive of peripheral nervous system complications. Clinical, laboratory and neurophysiological findings were evaluated by descriptive statistics and regression analysis to detect factors associated with muscle cramps. Patient’s sera were examined for anti-neuronal antibodies.</p> <h3>Results</h3><p>Nine patients had polyneuropathy, 4 had muscle cramps, and 14 had both. Median onset of polyneuropathy and muscle cramps was 6 and 9 months after allogeneic hematopoietic stem cell transplantation, respectively. Neurophysiology revealed a predominantly axonal polyneuropathy in 20 of 26 patients. In 4 of 19 patients electromyography showed signs of myopathy or myositis. Muscle cramps were more frequent during chronic than acute GVHD and affected muscles other than calves in 15 of 18 patients. They typically occurred daily, lasted 1 to 10 minutes with medium to severe pain intensity, compromised daily activity or sleep in 12, and were refractory to therapy in 4 patients. Muscle cramps were less likely with tacrolimus treatment and signs of severe polyneuropathy, but more likely with myopathic changes in electromyography and with incipient demyelinating polyneuropathy, shown by increased high frequency attenuation of the tibial nerve. Serological studies revealed antinuclear or antimitochondrial antibodies in a subset of patients. Two of 16 patients had a serum reactivity against peripheral nervous tissue.</p> <h3>Conclusion</h3><p>Muscle cramps are associated with chronic GVHD, often compromise daily activity, and correlate negatively with axonal polyneuropathy and positively with myopathy and incipient demyelination.</p> </div

Electrodiagnostic studies.

<p>CMAP = compound muscle action potential, DML = distal motor latency, HFA = high frequency attenuation, MUAP = motor unit action potential, NCV = nerve conduction velocity, SNAP = sensory nerve action potential.</p

Cerebrospinal fluid findings.

a<p>assessed by calculation of the CSF/serum quotient <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0044922#pone.0044922-Reiber1" target="_blank">[43]</a>.</p><p>CSF = cerebrospinal fluid, IgG = immunoglobulin G.</p