title: Contactin-associated protein-2 antibodies in non-paraneoplastic cerebellar ataxia.
abstract: BACKGROUND
  Relatively few studies have searched for potentially pathogenic antibodies in non-paraneoplastic patients with cerebellar ataxia.
  
  
  RESULTS
  We first screened sera from 52 idiopathic ataxia patients for binding of serum IgG antibodies to cerebellar neurons. One strong-binding serum was selected for immunoprecipitation and mass spectrometry, which resulted in the identification of contactin-associated protein 2 (CASPR2) as a major antigen. CASPR2 antibodies were then found by a cell-based assay in 9/88 (10%) ataxia patients, compared to 3/144 (2%) multiple sclerosis or dementia controls (p=0.011). CASPR2 is strongly expressed in the cerebellum, only partly in association with voltage-gated potassium channels.
  
  
  CONCLUSIONS
  Prospective studies are now needed to see whether identification of CASPR2 antibodies has relevance for the diagnosis and treatment of idiopathic cerebellar ataxia.
authors.affiliation: Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford University, Oxford, UK.
authors.forename: Esther B E
authors.initials: EB
authors.lastname: Becker
authors.forename: Luigi
authors.initials: L
authors.lastname: Zuliani
authors.forename: Rosemary
authors.initials: R
authors.lastname: Pettingill
authors.forename: Bethan
authors.initials: B
authors.lastname: Lang
authors.forename: Patrick
authors.initials: P
authors.lastname: Waters
authors.forename: Anna
authors.initials: A
authors.lastname: Dulneva
authors.forename: Frank
authors.initials: F
authors.lastname: Sobott
authors.forename: Mark
authors.initials: M
authors.lastname: Wardle
authors.forename: Francesc
authors.initials: F
authors.lastname: Graus
authors.forename: Luis
authors.initials: L
authors.lastname: Bataller
authors.forename: Neil P
authors.initials: NP
authors.lastname: Robertson
authors.forename: Angela
authors.initials: A
authors.lastname: Vincent
mesh_terms: D000818:Animals; D001327:Autoimmune Diseases / Q000276:immunology*; D002524:Cerebellar Ataxia / Q000276:immunology*; D002531:Cerebellum / Q000378:metabolism*; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009924:Organ Culture Techniques
chemical_list: C403049:CNTNAP2 protein, human; D007074:Immunoglobulin G; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins