title: Prevalence of anti-basal ganglia antibodies in adult obsessive-compulsive disorder: cross-sectional study.
abstract: BACKGROUND
  Symptoms of obsessive-compulsive disorder (OCD) have been described in neuropsychiatric syndromes associated with streptococcal infections. It is proposed that antibodies raised against streptococcal proteins cross-react with neuronal proteins (antigens) in the brain, particularly in the basal ganglia, which is a brain region implicated in OCD pathogenesis.
  
  
  OBJECTIVE
  To test the hypothesis that post-streptococcal autoimmunity, directed against neuronal antigens, may contribute to the pathogenesis of OCD in adults.
  
  
  METHODS
  Ninety-six participants with OCD were tested for the presence of anti-streptolysin-O titres (ASOT) and the presence of anti-basal ganglia antibodies (ABGA) in a cross-sectional study. The ABGA were tested for with western blots using three recombinant antigens; aldolase C, enolase and pyruvate kinase. The findings were compared with those in a control group of individuals with depression (n = 33) and schizophrenia (n = 17).
  
  
  RESULTS
  Positivity for ABGA was observed in 19/96 (19.8%) participants with OCD compared with 2/50 (4%) of controls (Fisher's exact test P = 0.012). The majority of positive OCD sera (13/19) had antibodies against the enolase antigen. No clinical variables were associated with ABGA positivity. Positivity for ASOT was not associated with ABGA positivity nor found at an increased incidence in participants with OCD compared with controls.
  
  
  CONCLUSIONS
  These findings support the hypothesis that central nervous system autoimmunity may have an aetiological role in some adults with OCD. Further study is required to examine whether the antibodies concerned are pathogenic and whether exposure to streptococcal infection in vulnerable individuals is a risk factor for the development of OCD.
authors.affiliation: National Institute of Health Research Specialist Biomedical Research Centre for Mental Health at South London and Maudsley NHS Foundation Trust and The Institute of Psychiatry, King's College London, London. timothy.nicholson@kcl.ac.uk
authors.forename: Timothy R J
authors.initials: TR
authors.lastname: Nicholson
authors.forename: Sumudu
authors.initials: S
authors.lastname: Ferdinando
authors.forename: Ravikumar B
authors.initials: RB
authors.lastname: Krishnaiah
authors.forename: Sophie
authors.initials: S
authors.lastname: Anhoury
authors.forename: Belinda R
authors.initials: BR
authors.lastname: Lennox
authors.forename: David
authors.initials: D
authors.lastname: Mataix-Cols
authors.forename: Anthony
authors.initials: A
authors.lastname: Cleare
authors.forename: David M
authors.initials: DM
authors.lastname: Veale
authors.forename: Lynne M
authors.initials: LM
authors.lastname: Drummond
authors.forename: Naomi A
authors.initials: NA
authors.lastname: Fineberg
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Church
authors.forename: Gavin
authors.initials: G
authors.lastname: Giovannoni
authors.forename: Isobel
authors.initials: I
authors.lastname: Heyman
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D000906:Antibodies / Q000097:blood*; D000941:Antigens / Q000276:immunology; D001479:Basal Ganglia / Q000276:immunology*; D015153:Blotting, Western; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009771:Obsessive-Compulsive Disorder / Q000276:immunology*; D013290:Streptococcal Infections / Q000276:immunology; D055815:Young Adult
chemical_list: D000906:Antibodies; D000941:Antigens