title: Limbic encephalitis due to GABAB and AMPA receptor antibodies: a case series.
abstract: BACKGROUND
  Two novel antibodies (abs) directed to γ-aminobutyric acid B receptor (GABA(B)R) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) in patients with limbic encephalitis (LE) were first described by the Philadelphia/Barcelona groups and confirmed by the Mayo group. We present a novel series for further clinical and paraclinical refinement.
  
  
  METHODS
  Serum and cerebrospinal fluid samples from a diagnostic laboratory were selected if found to be positive for GABA(B)R or AMPAR abs within a broad antineuronal ab panel. Data were retrospectively compiled.
  
  
  RESULTS
  In 10 patients, we detected abs to GABA(B)R. Median age was 70 years. Five of them were diagnosed with small cell lung cancer (SCLC). Intrathecal GABA(B)R ab synthesis was found in all six patients with sufficient data available (median ab-index: 76.8). On MRI, we found bilateral mediotemporal and in two cases cortical abnormalities. EEG revealed encephalopathy, partly with epileptiform discharges. Five patients received immunotherapy, two patients tumour treatment and three both therapies. Three patients died, in five patients cognitive functions declined, one patient improved slightly and one patient fully recovered. AMPAR abs were detected in three patients with mnestic disturbances. Median age was 60.7 years. The only female patient was diagnosed with ovarian cancer. None of the patients had intrathecal ab synthesis. MRI findings showed bilateral mediotemporal abnormalities. EEG was normal in all patients. Two of the three immunologically treated patients improved, one patient stabilised on a low level.
  
  
  CONCLUSIONS
  GABA(B)R and AMPAR abs are well associated with LE. GABA(B)R abs lead to severe clinical, neuroradiological and EEG abnormalities with poorer outcome.
authors.affiliation: Krankenhaus Mara, Epilepsy Center Bethel, Bielefeld, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Dogan Onugoren
authors.affiliation: Department of Neurology, Landeskrankenhaus, Bruck/Mur, Austria.
authors.forename: D
authors.initials: D
authors.lastname: Deuretzbacher
authors.affiliation: Department of Neurology, Maria Hilf Kliniken GmbH Mönchengladbach, University of Witten/Herdecke, Mönchengladabch, Germany.
authors.forename: C A
authors.initials: CA
authors.lastname: Haensch
authors.affiliation: Laboratory Krone, Bad Salzuflen, Germany.
authors.forename: H J
authors.initials: HJ
authors.lastname: Hagedorn
authors.affiliation: Evangelic Hospital Unna, University of Duisburg-Essen, Unna, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Halve
authors.affiliation: Department of Neurology, Helios Klinikum Wuppertal, Center for Clinical Research, and University Witten/Herdecke, Wuppertal, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Isenmann
authors.affiliation: Krankenhaus Mara, Epilepsy Center Bethel, Bielefeld, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Kramme
authors.affiliation: Department of Neurology, RoMed Kliniken Rosenheim, Rosenheim, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Lohner
authors.affiliation: Department of Neurology, University of Münster, Münster, Germany.
authors.forename: N
authors.initials: N
authors.lastname: Melzer
authors.affiliation: Department of Internal Medicine, Ospedale La Carità, Locarno, Switzerland.
authors.forename: R
authors.initials: R
authors.lastname: Monotti
authors.affiliation: Department of Neurology, Wilhelminenspital der Stadt Wien, Wien, Austria.
authors.forename: S
authors.initials: S
authors.lastname: Presslauer
authors.affiliation: Department of Neurology, Bethel-EvKB, Bielefeld, Germany.
authors.forename: W R
authors.initials: WR
authors.lastname: Schäbitz
authors.affiliation: Department of Internal Medicine, Ospedale La Carità, Locarno, Switzerland.
authors.forename: S
authors.initials: S
authors.lastname: Steffanoni
authors.affiliation: Department of Neurology, Georg-August-University, Göttingen, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Stoeck
authors.affiliation: Department of Neurology, Klinikum Merzig, Merzig, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Strittmatter
authors.affiliation: Department of Neurology, Klinikum Osnabrück, Osnabrück, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Stögbauer
authors.affiliation: Department of Neurology, Christian Doppler Medical Centre, Paracelsus Medical University, Salzburg, Austria.
authors.forename: E
authors.initials: E
authors.lastname: Trinka
authors.affiliation: Department of Neurology, Wagner-Jauregg Neuroscience Centre, Linz, Austria.
authors.forename: T J
authors.initials: TJ
authors.lastname: von Oertzen
authors.affiliation: Department of Neurology, University of Münster, Münster, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Wiendl
authors.affiliation: Krankenhaus Mara, Epilepsy Center Bethel, Bielefeld, Germany.
authors.forename: F G
authors.initials: FG
authors.lastname: Woermann
authors.affiliation: Krankenhaus Mara, Epilepsy Center Bethel, Bielefeld, Germany.
authors.forename: C G
authors.initials: CG
authors.lastname: Bien
mesh_terms: D000368:Aged; D001323:Autoantibodies / Q000097:blood*; D005260:Female; D006801:Humans; D020363:Limbic Encephalitis / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D018091:Receptors, AMPA / Q000276:immunology*; D018080:Receptors, GABA-B / Q000276:immunology*; D012189:Retrospective Studies
chemical_list: D001323:Autoantibodies; D018091:Receptors, AMPA; D018080:Receptors, GABA-B
keywords: CLINICAL NEUROLOGY; EPILEPSY; MRI; NEUROIMMUNOLOGY