title: Autoantibodies to neuronal surface antigens in thyroid antibody-positive and -negative limbic encephalitis.
abstract: BACKGROUND
  Thyroid antibodies (Thy-Abs) are frequently detected in various autoimmune disorders in coexistence with other systemic autoantibodies. In association with an encephalopathy, they are often taken as evidence of Hashimoto's encephalitis (HE). However, the presence of Thy-Abs in a cohort of limbic encephalitis (LE) patients and their association with anti-neuronal autoimmunity has not been explored.
  
  
  METHODS
  We investigated thyroid and anti-neuronal antibodies in the sera of 24 LE patients without identified tumors by cell-based assay and radioimmunoassay and evaluated their clinical features.
  
  
  RESULTS
  There was a female predominance in Thy-Ab-positive LE patients. Five of the eight Thy-Ab-positive patients and six of the 16 Thy-Ab-negative patients had antibodies to voltage-gated potassium channel (VGKC), N-methyl-D-aspartate receptor (NMDAR) or undefined surface antigens on cultured hippocampal neurons. There were trends towards fewer VGKC antibodies (1/8 vs. 5/16, P = 0.159) and more NMDAR antibodies (2/8 vs. 1/16, P = 0.095) among the Thy-Ab-positive LE patients; antibodies to undefined surface antigens were only identified in Thy-Ab-positive patients (2/8 vs. 0/16, P = 0.018). There were no distinguishing clinical features between Thy-Ab-positive patients with and without neuronal antibodies. However, patients with anti-neuronal antibodies showed a better treatment response.
  
  
  CONCLUSIONS
  Thy-Abs can be found in a high proportion of patients with non-paraneoplastic LE, often in association with antibodies to specific or as yet undefined neuronal surface antigens. These results suggest that acute idiopathic encephalitis patients with Thy-Abs should be closely monitored for ion-channel antibodies and it should not be assumed that they have HE.
authors.affiliation: Department of Neurology, Istanbul University, Istanbul Faculty of Medicine, Turkey, Turkey. drerdem@yahoo.com
authors.forename: Erdem
authors.initials: E
authors.lastname: Tüzün
authors.forename: Ece
authors.initials: E
authors.lastname: Erdağ
authors.forename: Hacer
authors.initials: H
authors.lastname: Durmus
authors.forename: Tanja
authors.initials: T
authors.lastname: Brenner
authors.forename: Recai
authors.initials: R
authors.lastname: Türkoglu
authors.forename: Murat
authors.initials: M
authors.lastname: Kürtüncü
authors.forename: Bethan
authors.initials: B
authors.lastname: Lang
authors.forename: Gülşen
authors.initials: G
authors.lastname: Akman-Demir
authors.forename: Mefkure
authors.initials: M
authors.lastname: Eraksoy
authors.forename: Angela
authors.initials: A
authors.lastname: Vincent
mesh_terms: D000328:Adult; D000818:Animals; D001323:Autoantibodies / Q000378:metabolism*; D002478:Cells, Cultured; D015331:Cohort Studies; D005260:Female; D006624:Hippocampus / Q000166:cytology; D006801:Humans; D007453:Iodide Peroxidase / Q000276:immunology; D020363:Limbic Encephalitis / Q000276:immunology* / Q000473:pathology*; D008297:Male; D008565:Membrane Proteins / Q000276:immunology*; D008875:Middle Aged; D009474:Neurons / Q000187:drug effects / Q000276:immunology; D024642:Potassium Channels, Voltage-Gated / Q000276:immunology; D011863:Radioimmunoassay / Q000379:methods; D051381:Rats; D016194:Receptors, N-Methyl-D-Aspartate / Q000276:immunology; D013954:Thyroglobulin / Q000276:immunology; D013961:Thyroid Gland / Q000276:immunology / Q000378:metabolism*
chemical_list: D001323:Autoantibodies; D008565:Membrane Proteins; D024642:Potassium Channels, Voltage-Gated; D016194:Receptors, N-Methyl-D-Aspartate; D013954:Thyroglobulin; D007453:Iodide Peroxidase