title: Antibodies in patients with neuropsychiatric systemic lupus erythematosus.
abstract: OBJECTIVE
  To investigate a target for antibodies in patients with neuropsychiatric systemic lupus erythematosus (NPSLE).
  
  
  BACKGROUND
  Pathogenesis of NPSLE may be related to autoantibody-mediated neural dysfunction, vasculopathy, and coagulopathy. However, very few autoantibodies are sensitive and specific to NPSLE because the neuropsychiatric syndromes associated with SLE are diverse in cause and presentation.
  
  
  METHODS
  We identified antibodies against brain antigens in the sera of 7 patients with NPSLE and 12 healthy controls by 2-dimensional electrophoresis, followed by Western blotting and liquid chromatography-tandem mass spectrometry (LC-MS/MS), using rat brain proteins as the antigen source.
  
  
  RESULTS
  Six antibodies were detected in patients with NPSLE. One of these 6 antibodies was found in antibodies against Rab guanosine diphosphate dissociation inhibitor alpha (alphaGDI) (which is specifically abundant in neurons and regulates synaptic vesicle exocytosis) in patients with NPSLE with psychosis. We tested more samples by 1-dimensional immunoblotting of human recombinant alphaGDI. Positivity of the anti-alphaGDI antibody was significantly higher in patients with NPSLE with psychosis (80%, 4 of 5) than in patients with NPSLE without psychosis (0%, 0 of 13), patients with systemic lupus erythematosus without neuropsychiatric symptoms (5.3%, 1 of 19), patients with multiple sclerosis (0%, 0 of 12), patients with infectious meningoencephalitis (0%, 0 of 13), patients with polyneuropathy (0%, 0 of 10), patients with psychotic syndromes (0%, 0 of 10), and healthy controls (0%, 0 of 12).
  
  
  CONCLUSIONS
  We propose that the anti-Rab guanosine diphosphate dissociation inhibitor alpha antibody is a candidate for further exploration as diagnostic marker of psychosis associated with neuropsychiatric systemic lupus erythematosus.
authors.affiliation: Department of Neurology and Geriatrics, Gifu University Graduate School of Medicine, Gifu, 1-1 Yanagido, Gifu City, Gifu 501-1194, Japan. kimura1@gifu-u.ac.jp
authors.forename: A
authors.initials: A
authors.lastname: Kimura
authors.forename: Y
authors.initials: Y
authors.lastname: Kanoh
authors.forename: T
authors.initials: T
authors.lastname: Sakurai
authors.forename: A
authors.initials: A
authors.lastname: Koumura
authors.forename: M
authors.initials: M
authors.lastname: Yamada
authors.forename: Y
authors.initials: Y
authors.lastname: Hayashi
authors.forename: Y
authors.initials: Y
authors.lastname: Tanaka
authors.forename: I
authors.initials: I
authors.lastname: Hozumi
authors.forename: M
authors.initials: M
authors.lastname: Takemura
authors.forename: M
authors.initials: M
authors.lastname: Seishima
authors.forename: T
authors.initials: T
authors.lastname: Inuzuka
mesh_terms: D000293:Adolescent; D000328:Adult; D000369:Aged, 80 and over; D001323:Autoantibodies / Q000097:blood / Q000276:immunology*; D015415:Biomarkers; D015153:Blotting, Western; D015180:Electrophoresis, Gel, Two-Dimensional; D005089:Exocytosis / Q000276:immunology; D005260:Female; D020730:Guanine Nucleotide Dissociation Inhibitors / Q000276:immunology; D006801:Humans; D020945:Lupus Vasculitis, Central Nervous System / Q000097:blood / Q000150:complications / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D009474:Neurons / Q000276:immunology; D011618:Psychotic Disorders / Q000097:blood / Q000209:etiology / Q000276:immunology*; D013572:Synaptic Vesicles / Q000276:immunology; D053719:Tandem Mass Spectrometry
chemical_list: D001323:Autoantibodies; D015415:Biomarkers; C086796:GDP dissociation inhibitor 1; D020730:Guanine Nucleotide Dissociation Inhibitors