Roberta Vitaliani

Bio: Roberta Vitaliani is an academic researcher from University of Pennsylvania. The author has contributed to research in topics: Limbic encephalitis & Paraneoplastic cerebellar degeneration. The author has an hindex of 14, co-authored 18 publications receiving 2259 citations.

AMPA receptor antibodies in limbic encephalitis alter synaptic receptor location

Abstract: Background Limbic encephalitis (LE) frequently associates with antibodies to cell surface antigens. Characterization of these antigens is important because it facilitates the diagnosis of those disorders that are treatment-responsive. We report a novel antigen of LE and the effect of patients' antibodies on neuronal cultures.

Paraneoplastic encephalitis, psychiatric symptoms, and hypoventilation in ovarian teratoma

Abstract: We report four young women who developed acute psychiatric symptoms, seizures, memory deficits, decreased level of consciousness, and central hypoventilation associated with ovarian teratoma (OT) and cerebrospinal fluid (CSF) inflammatory abnormalities. Three patients recovered with treatment of the tumor or immunosuppression and one died of the disorder. Five other OT patients with a similar syndrome and response to treatment have been reported. Our patients' serum or CSF showed immunolabeling of antigens that were expressed at the cytoplasmic membrane of hippocampal neurons and processes and readily accessed by antibodies in live neurons. Immunoprobing of a hippocampal-expression library resulted in the isolation of EFA6A, a protein that interacts with a member of the two-pore-domain potassium channel family and is involved in the regulation of the dendritic development of hippocampal neurons. EFA6A-purified antibodies reproduced the hippocampal immunolabeling of all patients' antibodies and colocalized with them at the plasma membrane. These findings indicate that in a young woman with acute psychiatric symptoms, seizures, and central hypoventilation, a paraneoplastic immune-mediated syndrome should be considered. Recognition of this disorder is important because despite the severity of the symptoms, patients usually recover. The location and function of the isolated antigen suggest that the disorder is directly mediated by antibodies.

Treatment-responsive limbic encephalitis identified by neuropil antibodies: MRI and PET correlates

Abstract: We report seven patients, six from a single institution, who developed subacute limbic encephalitis initially considered of uncertain aetiology. Four patients presented with symptoms of hippocampal dysfunction (i.e. severe short-term memory loss) and three with extensive limbic dysfunction (i.e. confusion, seizures and suspected psychosis). Brain MRI and [18F]fluorodeoxyglucose (FDG)-PET complemented each other but did not overlap in 50% of the patients. Combining both tests, all patients had temporal lobe abnormalities, five with additional areas involved. In one patient, FDG hyperactivity in the brainstem that was normal on MRI correlated with central hypoventilation; in another case, hyperactivity in the cerebellum anticipated ataxia. All patients had abnormal CSF: six pleocytosis, six had increased protein concentration, and three of five examined had oligoclonal bands. A tumour was identified and removed in four patients (mediastinal teratoma, thymoma, thymic carcinoma and thyroid cancer) and not treated in one (ovarian teratoma). An immunohistochemical technique that facilitates the detection of antibodies to cell surface or synaptic proteins demonstrated that six patients had antibodies to the neuropil of hippocampus or cerebellum, and one to intraneuronal antigens. Only one of the neuropil antibodies corresponded to voltage-gated potassium channel (VGKC) antibodies; the other five (two with identical specificity) reacted with antigens concentrated in areas of high dendritic density or synaptic-enriched regions of the hippocampus or cerebellum. Preliminary characterization of these antigens indicates that they are diverse and expressed on the neuronal cell membrane and dendrites; they do not co-localize with VGKCs, but partially co-localize with spinophilin. A target autoantigen in one of the patients co-localizes with a cell surface protein involved in hippocampal dendritic development. All patients except the one with antibodies to intracellular antigens had dramatic clinical and neuroimaging responses to immunotherapy or tumour resection; two patients had neurological relapse and improved with immunotherapy. Overall, the phenotype associated with the novel neuropil antibodies includes dominant behavioural and psychiatric symptoms and seizures that often interfere with the evaluation of cognition and memory, and brain MRI or FDG-PET abnormalities less frequently restricted to the medial temporal lobes than in patients with classical paraneoplastic or VGKC antibodies. When compared with patients with VGKC antibodies, patients with these novel antibodies are more likely to have CSF inflammatory abnormalities and systemic tumours (teratoma and thymoma), and they do not develop SIADH-like hyponatraemia. Although most autoantigens await characterization, all share intense expression by the neuropil of hippocampus, with patterns of immunolabelling characteristic enough to suggest the diagnosis of these disorders and predict response to treatment.

Paraneoplastic neurologic syndrome in the PNS Euronetwork database: a European study from 20 centers.

Abstract: Background Paraneoplastic neurologic syndrome (PNS) represents the remote effects of cancer on the nervous system. Diagnostic criteria for the syndrome were published by the PNS Euronetwork and form the basis of a database to collect standardized clinical data from patients with PNS. Objectives To analyze various types of PNS, frequent tumor and antibody associations, clinical characteristics of individual syndromes, and possible therapeutic and prognostic strategies. Design Prospective case series and database study. Setting Twenty European centers. Patients Patients were recruited from January 1, 2000, to December 31, 2008. Main Outcome Measures Based on diagnostic criteria published by the PNS Euronetwork consortium, clinical characteristics of classic PNS and several other less well-characterized syndromes associated with cancer were assessed. Results Data from 979 patients were analyzed, representing the largest PNS investigation to date. The findings elucidate the clinical evolution of paraneoplastic cerebellar syndrome according to the onconeural antibodies present, the heterogeneity and prognosis of dysautonomic disorders, and the clinical variability of paraneoplastic limbic encephalitis. Conclusion The study results confirm that PNS influences oncologic patient survival. Tumors are the main cause of death, but some types of PNS (such as dysautonomia) have a poorer prognosis than malignant neoplasms.

Spontaneous pain, pain threshold, and pain tolerance in Parkinson’s disease

Abstract: The mechanisms underlying pain in Parkinson’s disease (PD) are unclear. Although a few studies have reported that PD patients may have low pain threshold and tolerance, none could accurately assess whether there was a correlation between sensory thresholds and demographic/clinical features of PD patients. Thus, tactile threshold, pain threshold, and pain tolerance to electrical stimuli in the hands and feet were assessed in 106 parkinsonian patients (of whom 66 reported chronic pain) and 51 age- and sex-matched healthy subjects. Linear regression models determined relationships between psychophysical parameters and demographic/clinical features. Female gender, severity of disease, medical disease associated with painful symptoms, and dyskinesia were more frequently observed in PD patients experiencing pain, even though dyskinesia did not reach significance. Pain threshold and pain tolerance were significantly lower in PD patients than in control subjects, whereas the tactile threshold yielded comparable values in both groups. Multivariable linear regression analyses yielded significant inverse correlations of pain threshold and pain tolerance with motor symptom severity and Beck depression inventory. Pain threshold and pain tolerance did not differ between PD patients with and without pain. In the former group, there was no relationship between pain threshold and the intensity/type of pain, and number of painful body parts. These findings suggest that pain threshold and pain tolerance tend to decrease as PD progresses, which can predispose to pain development. Female gender, dyskinesia, medical conditions associated with painful symptoms, and postural abnormalities secondary to rigidity/bradikinesia may contribute to the appearance of spontaneous pain in predisposed subjects.

A clinical approach to diagnosis of autoimmune encephalitis

Abstract: Summary Encephalitis is a severe inflammatory disorder of the brain with many possible causes and a complex differential diagnosis. Advances in autoimmune encephalitis research in the past 10 years have led to the identification of new syndromes and biomarkers that have transformed the diagnostic approach to these disorders. However, existing criteria for autoimmune encephalitis are too reliant on antibody testing and response to immunotherapy, which might delay the diagnosis. We reviewed the literature and gathered the experience of a team of experts with the aims of developing a practical, syndrome-based diagnostic approach to autoimmune encephalitis and providing guidelines to navigate through the differential diagnosis. Because autoantibody test results and response to therapy are not available at disease onset, we based the initial diagnostic approach on neurological assessment and conventional tests that are accessible to most clinicians. Through logical differential diagnosis, levels of evidence for autoimmune encephalitis (possible, probable, or definite) are achieved, which can lead to prompt immunotherapy.

Treatment and prognostic factors for long-term outcome in patients with anti-NMDA receptor encephalitis: an observational cohort study

Abstract: Summary Background Anti-NMDA receptor (NMDAR) encephalitis is an autoimmune disorder in which the use of immunotherapy and the long-term outcome have not been defined. We aimed to assess the presentation of the disease, the spectrum of symptoms, immunotherapies used, timing of improvement, and long-term outcome. Methods In this multi-institutional observational study, we tested for the presence of NMDAR antibodies in serum or CSF samples of patients with encephalitis between Jan 1, 2007, and Jan 1, 2012. All patients who tested positive for NMDAR antibodies were included in the study; patients were assessed at symptom onset and at months 4, 8, 12, 18, and 24, by use of the modified Rankin scale (mRS). Treatment included first-line immunotherapy (steroids, intravenous immunoglobulin, plasmapheresis), second-line immunotherapy (rituximab, cyclophosphamide), and tumour removal. Predictors of outcome were determined at the Universities of Pennsylvania (PA, USA) and Barcelona (Spain) by use of a generalised linear mixed model with binary distribution. Results We enrolled 577 patients (median age 21 years, range 8 months to 85 years), 211 of whom were children ( Interpretation Most patients with anti-NMDAR encephalitis respond to immunotherapy. Second-line immunotherapy is usually effective when first-line treatments fail. In this cohort, the recovery of some patients took up to 18 months. Funding The Dutch Cancer Society, the National Institutes of Health, the McKnight Neuroscience of Brain Disorders award, The Fondo de Investigaciones Sanitarias, and Fundacio la Marato de TV3.

Paraneoplastic anti–N‐methyl‐D‐aspartate receptor encephalitis associated with ovarian teratoma

Abstract: Objective To report the autoantigens of a new category of treatment-responsive paraneoplastic encephalitis.

Clinical experience and laboratory investigations in patients with anti-NMDAR encephalitis

Abstract: Since its discovery in 2007, the encephalitis associated with antibodies against the N-methyl-D-aspartate receptor (NMDAR) has entered the mainstream of neurology and other disciplines. Most patients with anti-NMDAR encephalitis develop a multistage illness that progresses from psychosis, memory deficits, seizures, and language disintegration into a state of unresponsiveness with catatonic features often associated with abnormal movements, and autonomic and breathing instability. The disorder predominantly affects children and young adults, occurs with or without tumour association, and responds to treatment but can relapse. The presence of a tumour (usually an ovarian teratoma) is dependent on age, sex, and ethnicity, being more frequent in women older than 18 years, and slightly more predominant in black women than it is in white women. Patients treated with tumour resection and immunotherapy (corticosteroids, intravenous immunoglobulin, or plasma exchange) respond faster to treatment and less frequently need second-line immunotherapy (cyclophosphamide or rituximab, or both) than do patients without a tumour who receive similar initial immunotherapy. More than 75% of all patients have substantial recovery that occurs in inverse order of symptom development and is associated with a decline of antibody titres. Patients' antibodies cause a titre-dependent, reversible decrease of synaptic NMDAR by a mechanism of crosslinking and internalisation. On the basis of models of pharmacological or genetic disruption of NMDAR, these antibody effects reveal a probable pathogenic relation between the depletion of receptors and the clinical features of anti-NMDAR encephalitis.

Antibodies to Kv1 potassium channel-complex proteins leucine-rich, glioma inactivated 1 protein and contactin-associated protein-2 in limbic encephalitis, Morvan's syndrome and acquired neuromyotonia.

Abstract: Antibodies that immunoprecipitate (125)I-alpha-dendrotoxin-labelled voltage-gated potassium channels extracted from mammalian brain tissue have been identified in patients with neuromyotonia, Morvan's syndrome, limbic encephalitis and a few cases of adult-onset epilepsy. These conditions often improve following immunomodulatory therapies. However, the proportions of the different syndromes, the numbers with associated tumours and the relationships with potassium channel subunit antibody specificities have been unclear. We documented the clinical phenotype and tumour associations in 96 potassium channel antibody positive patients (titres >400 pM). Five had thymomas and one had an endometrial adenocarcinoma. To define the antibody specificities, we looked for binding of serum antibodies and their effects on potassium channel currents using human embryonic kidney cells expressing the potassium channel subunits. Surprisingly, only three of the patients had antibodies directed against the potassium channel subunits. By contrast, we found antibodies to three proteins that are complexed with (125)I-alpha-dendrotoxin-labelled potassium channels in brain extracts: (i) contactin-associated protein-2 that is localized at the juxtaparanodes in myelinated axons; (ii) leucine-rich, glioma inactivated 1 protein that is most strongly expressed in the hippocampus; and (iii) Tag-1/contactin-2 that associates with contactin-associated protein-2. Antibodies to Kv1 subunits were found in three sera, to contactin-associated protein-2 in 19 sera, to leucine-rich, glioma inactivated 1 protein in 55 sera and to contactin-2 in five sera, four of which were also positive for the other antibodies. The remaining 18 sera were negative for potassium channel subunits and associated proteins by the methods employed. Of the 19 patients with contactin-associated protein-antibody-2, 10 had neuromyotonia or Morvan's syndrome, compared with only 3 of the 55 leucine-rich, glioma inactivated 1 protein-antibody positive patients (P < 0.0001), who predominantly had limbic encephalitis. The responses to immunomodulatory therapies, defined by changes in modified Rankin scores, were good except in the patients with tumours, who all had contactin-associated-2 protein antibodies. This study confirms that the majority of patients with high potassium channel antibodies have limbic encephalitis without tumours. The identification of leucine-rich, glioma inactivated 1 protein and contactin-associated protein-2 as the major targets of potassium channel antibodies, and their associations with different clinical features, begins to explain the diversity of these syndromes; furthermore, detection of contactin-associated protein-2 antibodies should help identify the risk of an underlying tumour and a poor prognosis in future patients.