Cross-reactivity of a pathogenic autoantibody to a tumor antigen in GABAA receptor encephalitis.

Encephalitis associated with antibodies against the neuronal gamma-aminobutyric acid A receptor (GABAA-R) is a rare form of autoimmune encephalitis. The pathogenesis is still unknown but autoimmune mechanisms were surmised. Here we identified a strongly expanded B cell clone in the cerebrospinal fluid of a patient with GABAA-R encephalitis. We expressed the antibody produced by it and showed by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry that it recognizes the GABAA-R. Patch-clamp recordings revealed that it tones down inhibitory synaptic transmission and causes increased excitability of hippocampal CA1 pyramidal neurons. Thus, the antibody likely contributed to clinical disease symptoms. Hybridization to a protein array revealed the cross-reactive protein LIM-domain-only protein 5 (LMO5), which is related to cell-cycle regulation and tumor growth. We confirmed LMO5 recognition by immunoprecipitation and ELISA and showed that cerebrospinal fluid samples from two other patients with GABAA-R encephalitis also recognized LMO5. This suggests that cross-reactivity between GABAA-R and LMO5 is frequent in GABAA-R encephalitis and supports the hypothesis of a paraneoplastic etiology.

Evaluation of the methoxy-X04 derivative BSC4090 for diagnosis of prodromal and early Alzheimer's disease from bioptic olfactory mucosa.

Alzheimer's disease (AD) pathology precedes the onset of clinical symptoms by several decades. Thus, biomarkers are required to identify prodromal disease stages to allow for the early and effective treatment. The methoxy-X04-derivative BSC4090 is a fluorescent ligand which was designed to target neurofibrillary tangles in AD. BSC4090 staining was previously detected in post-mortem brains and olfactory mucosa derived from AD patients. We tested BSC4090 as a potential diagnostic marker of prodromal and early AD using olfactory mucosa biopsies from 12 individuals with AD, 13 with mild cognitive impairment (MCI), and 10 cognitively normal (CN) controls. Receiver-operating curve analysis revealed areas under the curve of 0.78 for AD versus CN and of 0.86 for MCI due to AD versus MCI of other causes. BSC4090 labeling correlated significantly with cerebrospinal fluid levels of tau protein phosphorylated at T181. Using NMR spectroscopy, we find that BSC4090 binds to fibrillar and pre-fibrillar but not to monomeric tau. Thus, BSC4090 may be an interesting candidate to detect AD at the early disease stages.

Diagnostic red flags: steroid-treated malignant CNS lymphoma mimicking autoimmune inflammatory demyelination.

The presence of inflammation and demyelination in a central nervous system (CNS) biopsy points towards a limited, yet heterogeneous group of pathologies, of which multiple sclerosis (MS) represents one of the principal considerations. Inflammatory demyelination has also been reported in patients with clinically suspected primary central nervous system lymphoma (PCNSL), especially when steroids had been administered prior to biopsy acquisition. The histopathological changes induced by corticosteroid treatment can range from mild reduction to complete disappearance of lymphoma cells. It has been proposed that in the absence of neoplastic B cells, these biopsies are indistinguishable from MS, yet despite the clinical relevance, no histological studies have specifically compared the two entities. In this work, we analyzed CNS biopsies from eight patients with inflammatory demyelination in whom PCNSL was later histologically confirmed, and compared them with nine well defined early active multiple sclerosis lesions. In the patients with steroid-treated PCNSL (ST-PCNSL) the interval between first and second biopsy ranged from 3 to 32 weeks; all of the patients had received corticosteroids before the first, but not the second biopsy. ST-PCNSL patients were older than MS patients (mean age: ST-PCNSL: 62 ± 4 years, MS: 30 ± 2 years), and histological analysis revealed numerous apoptoses, patchy and incomplete rather than confluent and complete demyelination and a fuzzy lesion edge. The loss of Luxol fast blue histochemistry was more profound than that of myelin proteins in immunohistochemistry, and T cell infiltration in ST-PCNSL exceeded that in MS by around fivefold (P = 0.005). Our data indicate that in the presence of extensive inflammation and incomplete, inhomogeneous demyelination, the neuropathologist should refrain from primarily considering autoimmune inflammatory demyelination and, even in the absence of lymphoma cells, instigate close clinical follow-up of the patient to detect recurrent lymphoma.

Fingolimod (FTY-720) is Capable of Reversing Tumor Necrosis Factor Induced Decreases in Cochlear Blood Flow.

HYPOTHESIS: The potential of Fingolimod (FTY-720), a sphingosine-1-phosphate analogue, to revoke the changes in cochlear blood flow induced by tumor necrosis factor (TNF) was investigated. BACKGROUND: Impairment of cochlear blood flow has often been considered as the common final pathway of various inner ear pathologies. TNF, an ubiquitous cytokine, plays a major role in these pathologies, reducing cochlear blood flow via sphingosine-1-phosphate-signaling. METHODS: Fifteen Dunkin-Hartley guinea pigs were randomly assigned to one of three groups (placebo/placebo, TNF/placebo, TNF/FTY-720). Cochlear microcirculation was quantified over 60 minutes by in vivo fluorescence microscopy before and after topical application of placebo or TNF (5 ng/ml) and after subsequent application of placebo or FTY-720 (200 µg/ml). RESULTS: Treatment with TNF led to a significant decrease of cochlear blood flow.Following this, application of placebo caused no significant changes while application of FTY-720 caused a significant rise in cochlear blood flow. CONCLUSIONS: FTY-720 is capable of reversing changes in cochlear blood flow induced by application of TNF. This makes FTY-720 a valid candidate for potential treatment of numerous inner ear pathologies.

New-Onset Headache in Patients With Autoimmune Encephalitis Is Associated With anti-NMDA-Receptor Antibodies.

OBJECTIVE: We tested the hypotheses (i) that autoimmune encephalitis is associated with new-onset headache, and (ii) that the occurrence of headache is associated with the presence of anti-N-methyl-D-aspartate (NMDA)-receptor antibodies. BACKGROUND: Autoimmune encephalitis presents with cognitive dysfunction as well as neuro-psychiatric symptoms. Its pathophysiology might involve antibody-mediated dysfunction of the glutamatergic system as indicated by the presence of anti-NMDA-receptor antibodies in some patients. METHODS: In this cross-sectional study, patients with autoimmune encephalitis were assessed with a standardized interview for previous headache and headache associated with autoimmune encephalitis. Headache was classified according to the International Classification of Headache Disorders, second edition. Clinical and paraclinical findings were correlated with the occurrence of headache. RESULTS: Of 40 patients with autoimmune encephalitis, 19 did not have a history of headache. Of those, nine suffered from encephalitis-associated headache. Seven of these nine had anti-NMDA-receptor antibodies in contrast to only two among the remaining 10 patients without new-onset headache (P = .023, odds ratio: 14, 95% confidence interval: 1.5; 127). In most patients headache occurred in attacks on more than 15 days/month, was severe, and of short duration (less than 4 hours). International Headache Society criteria for migraine were met in three patients. CONCLUSIONS: New-onset headache is a relevant symptom in patients with autoimmune encephalitis who have no history of previous headache, especially in the subgroup with anti-NMDA-receptor antibodies. This indicates a thorough investigation for secondary headaches including anti-NMDA-R antibodies for patients with new-onset headache and neuropsychiatric findings. Glutamatergic dysfunction might be important for the generation of head pain but may only occasionally be sufficient to trigger migraine-like attacks in nonmigraineurs.

Rebound of disease activity after withdrawal of fingolimod (FTY720) treatment.

BACKGROUND: The oral sphingosine-1-phosphate receptor modulator fingolimod (FTY720) was recently approved for the treatment of relapsing-remitting multiple sclerosis. To date, data about a possible recurrence of disease activity after discontinuation of fingolimod treatment are scarce. OBJECTIVE: To describe a patient who discontinued fingolimod treatment after a local malignant melanoma was diagnosed. Three months after cessation, he had a striking rebound of multiple sclerosis activity. DESIGN: Case report and review of literature. SETTING: Institute of Clinical Neuroimmunology, Ludwig-Maximilians-University, Munich, Germany. PATIENT: A 45-year-old man diagnosed as having relapsing-remitting multiple sclerosis. MAIN OUTCOME MEASURES: Multiple sclerosis disease activity including annual relapse rate, Expanded Disability Status Scale score, and number of gadolinium-enhancing lesions on magnetic resonance imaging before, during, and after treatment with fingolimod. RESULTS: Three months after discontinuation of treatment with fingolimod, the patient experienced a severe relapse, with Expanded Disability Status Scale score progression from 2.5 to 4.5. On brain and spinal magnetic resonance imaging, he showed a rebound of disease activity, with a drastic increase of gadolinium-enhancing lesions (>20). CONCLUSIONS: Two aspects relevant to any newly approved multiple sclerosis treatment with immunomodulatory properties are highlighted with this case: first, possible rebound of disease activity after discontinuation; second, the occurrence of a tumor as a possible treatment-related complication.

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 < 0.0003), to more often have signs of co-existing autoimmunity (p < 0.00001), and to experience more severe clinical attacks. A visual acuity of ≤ 0.1 during acute optic neuritis (ON) attacks was more frequent among seropositives (p < 0.002). Similarly, motor symptoms were more common in seropositive patients, the median Medical Research Council scale (MRC) grade worse, and MRC grades ≤ 2 more frequent, in particular if patients met the 2006 revised criteria (p < 0.005, p < 0.006 and p < 0.01, respectively), the total spinal cord lesion load was higher (p < 0.006), and lesions ≥ 6 vertebral segments as well as entire spinal cord involvement more frequent (p < 0.003 and p < 0.043). By contrast, bilateral ON at onset was more common in seronegatives (p < 0.007), as was simultaneous ON and myelitis (p < 0.001); accordingly, the time to diagnosis of NMO was shorter in the seronegative group (p < 0.029). The course of disease was more often monophasic in seronegatives (p < 0.008). Seropositives and seronegatives did not differ significantly with regard to age at onset, time to relapse, annualized relapse rates, outcome from relapse (complete, partial, no recovery), annualized EDSS increase, mortality rate, supratentorial brain lesions, brainstem lesions, history of carcinoma, frequency of preceding infections, oligoclonal bands, or CSF pleocytosis. Both the time to relapse and the time to diagnosis was longer if the disease started with ON (p < 0.002 and p < 0.013). Motor symptoms or tetraparesis at first myelitis and > 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.

De-escalation from natalizumab in multiple sclerosis: recurrence of disease activity despite switching to glatiramer acetate.

Natalizumab (NAT) is an effective therapy for relapsing-remitting multiple sclerosis (MS), but is associated with an increased risk of progressive multifocal leucoencephalopathy after 2 years therapy. Thus, NAT treated patients often decide to stop NAT therapy after 2 years. Reports on recurrence of disease activity after NAT discontinuation are controversial. We studied disease activity in 13 MS patients who stopped NAT therapy and either remained without disease modifying therapy (no DMT, n = 6), or switched to glatiramer acetate (GLAT, n = 7). Annual relapse rate (ARR), expanded disability status scale (EDSS), and number of patients with contrast-enhancing-lesions (Gd+) on MRI before, during and within 1 year after NAT were determined. We observed recurrence of disease activity in both groups (5/7 GLAT treated patients and 6/6 patients without DMT) within 12 months after cessation of NAT (mean time to first relapse was 5.5 months for all patients). One of the GLAT treated patients and three patients without DMT had severe relapses with sustained EDSS worsening. No differences in ARR, EDSS and MRI parameters were seen between both groups. Patients with relapses after NAT therapy, however, tended to show higher disease activity (EDSS, ARR) before initiation of NAT therapy compared to patients without relapses. Duration of NAT treatment was not associated with higher disease activity after NAT discontinuation. In this observation the majority of patients showed reappearance of disease activity after discontinuation of NAT regardless of whether they switched to GLAT or remained without DMT. Further treatment strategies are warranted for patients who discontinue NAT therapy.

Managing non-paraneoplastic Lambert-Eaton myasthenic syndrome: clinical characteristics in 25 German patients.

In about 40% of patients LEMS is not a paraneoplastic phenomenon (NT-LEMS). Several clinical aspects important to these patients remain open, especially the question when a LEMS can definitely be diagnosed as NT-LEMS. Here we describe a series of 25 German NT-LEMS patients regarding their clinical characteristics, duration of symptoms, value of serological markers, paraneoplastic antibodies and FDG-PET/CT. Furthermore, we discuss the current diagnostic criteria of NT-LEMS.

Favorable response to rituximab in a patient with anti-VGCC-positive Lambert-Eaton myasthenic syndrome and cerebellar dysfunction.

Lambert-Eaton myasthenic syndrome (LEMS) is an autoimmune disease that is characterized by impaired transmission across the neuromuscular junction due to autoantibodies directed against the presynaptic voltage-gated calcium channels (VGCC-ab). Clinical symptoms are usually characterized by proximal muscle weakness and mild dysautonomia. In some patients there are signs of cerebellar dysfunction as well, usually associated with cancer. Here we report the long-term follow-up of a patient with VGCC-ab-positive LEMS and a severe cerebellar syndrome but without evidence of cancer over 5 years. While conventional immunosuppressive therapy (steroids, azathioprine) failed, he improved with plasma exchange and consecutive treatment with rituximab. Muscle Nerve 40: 305-308, 2009.

Cross-reactive T-cell receptors in tumor and paraneoplastic target tissue.

BACKGROUND: According to established criteria, paraneoplastic encephalomyelitis with adrenal neuroblastoma comprises a definite paraneoplastic neurologic syndrome. OBJECTIVE: To detect T-cell clones that cross-react against antigens shared between tumor and nervous system. DESIGN: Case study. SETTING: Academic research. Patient A 22-year-old woman having paraneoplastic encephalomyelitis with adrenal neuroblastoma. MAIN OUTCOME MEASURES: We compared the T-cell receptor repertoires expressed in blood, cerebrospinal fluid, and neuroblastoma tumor tissue using complementary determining region 3 (CDR3) spectratyping and clone-specific polymerase chain reaction. RESULTS: The T-cell receptor repertoire in cerebrospinal fluid was narrow compared with that in tumor and blood. Four T-cell clones from different tissues had identical T-cell receptor beta chains. Remarkably, the chains showed identical amino acid sequences but different nucleotide sequences. CONCLUSIONS: These T cells represent ontogenetically distinct clones but share functionally identical receptors. They recognize the same antigen in nervous system and tumor tissue and represent an attractive target for selective therapy.

Inadvertent intra-arterial contrast agent injection mimicking bilateral occlusion of the internal carotid arteries in a patient with suspected stroke on maximum-slope, nondeconvolution perfusion computed tomography.

BACKGROUND AND PURPOSE: Inadvertent contrast agent injection in the left cubital artery may lead to decisively altered perfusion parameters in stroke CT. These effects have not previously been described. Summary of Case- A 77-year-old woman with a suspected stroke underwent subsequent stroke CT imaging. No signs of intracranial hemorrhage or acute cerebral ischemia were noted on nonenhanced CT. Qualitative analysis of perfusion CT using the maximum slope model demonstrated an extremely delayed and decreased perfusion of the territories of the anterior circulation system and higher values of cerebral blood flow and blood volume of the posterior circulation system mimicking a bilateral occlusion of the internal carotid arteries. CT angiography revealed no relevant stenoses or occlusions of the internal carotid arteries. Intensive investigation into the potential causes of these controversial findings showed that the contrast medium was administered into the left brachial artery due to inadvertent arterial placement of the antecubital catheter. CONCLUSIONS: It is important to be familiar with this unusual constellation of perfusion parameters to avoid diagnostic uncertainty in patients with an inadvertent intra-arterial application of contrast agent.

Lambert-eaton myasthenic syndrome differential reactivity of tumor versus non-tumor patients to subunits of the voltage-gated calcium channel.

OBJECTIVE: Lambert-Eaton myasthenic syndrome (LEMS) is an autoimmune disease in which the transmission across the neuromuscular junction is disturbed by autoantibodies directed against the presynaptic P/Q-type voltage-gated calcium channels (VGCC). LEMS is paraneoplastic (T-LEMS) in about 60% of patients mostly associated with a small cellular lung carcinoma (SCLC), but occurs spontaneously without a tumor in 40% (NT-LEMS). In most cases neurologic symptoms appear before tumor diagnosis, but there is as yet no clear specific serologic marker to distinguish between NT- and T-LEMS. METHODS: To see whether antibodies from patients with NT- and T-LEMS differentially recognize antigenic sites of the alpha 1A subunit of P/Q-type VGCC, we studied serum samples from 22 T-LEMS and 24 NT-LEMS patients. Sera reactivity was tested by Western blot analysis to recombinant proteins corresponding to the extracellular S5-S6 linker region of three out of four domains forming the alpha 1 subunit of P/Q-type VGCC. RESULTS: Sera from 9/24 (37,5%) NT-LEMS patients, but only 1/22 (4,6%) T-LEMS patients recognized domain IV (p=0,011). Seroreactivity to domains I and III was similar for NT-LEMS and T-LEMS patients (domain I: 8%/14%; domain III: 46%/41%, not significant). CONCLUSIONS: These data suggest that an antibody response to domain IV is more common in LEMS without tumor than in paraneoplastic LEMS. This may have implications for diagnostic workup in LEMS patients without previously established diagnosis of a tumor. Additionally this could point towards a differential autoimmune pathogenesis between T-LEMS and NT-LEMS.

Modelling paraneoplastic CNS disease: T-cells specific for the onconeuronal antigen PNMA1 mediate autoimmune encephalomyelitis in the rat.

Antibodies directed against onconeuronal antigens provide a specific diagnostic marker for paraneoplastic neurological syndromes (PNS) and suggest that these autoantigens are targeted during disease pathogenesis. However, so far attempts to generate autoimmune models of PNS have been unsuccessful. Here we show that the adoptive transfer of T-cells specific for the autologous onconeuronal antigen Pnma1 cause encephalomyelitis in the Dark Agouti (DA) rat. The sequence of rat Ma1 (rPnma1) was determined by RT-PCR using primers for human PNMA1, followed by 5' and 3' genome walking. Rat Pnma1 is 93.8% identical to human PNMA1 at the amino acid level. Rat Pnma1 was cloned into the expression vector pQE60, and recombinant protein purified by metal chelate chromatography. Female DA rats were immunized with recombinant rPnma1 and rPnma1-specific CD4+ T-helper 1 (Th1) T-cell lines generated from the draining lymph nodes 10 days post-immunization. Freshly activated T-cell blasts were transferred into naive female DA rats, which were killed up to 9 days later. Proliferation assays demonstrated that the CD4+ Th1 T-cells were highly specific for rPnma1. After T-cell transfer the recipients developed a perivascular inflammatory response involving CNS regions affected in human disease. Anti-Pnma1 antibodies were induced by protein immunization, but this was associated with minimal CNS pathology. The induction of an inflammatory response in the CNS following the adoptive transfer of rat Pnma1-specific T-cells demonstrates for the first time that a paraneoplastic autoantigen can initiate a pathogenic effector T-cell response. This animal model strongly supports the hypothesis that the pathogenesis of paraneoplastic CNS neurological syndromes in man involves an autoimmune T-cell component.