title: The relationship between group A streptococcal infections and Tourette syndrome: a study on a large service-based cohort.
abstract: OBJECTIVE
  To evaluate the relationship between diagnosis and clinical course of Tourette syndrome and group A Streptococcus (GAS).
  
  
  METHODS
  GAS infections, anti-streptococcal, and anti-basal ganglia antibodies (ABGA) were compared between 168 patients (136 males, 32 females) with Tourette syndrome; (median [range] age [25th-75th centile] 10y [8-11y]); median Tourette syndrome duration (25th-75th centile), 3y (1y 3mo-5y 9mo) and a comparison group of 177 patients (117 males, 60 females) with epileptic or sleep disorders median age [25th-75th centile], 10y [8y-1y 6mo]). One hundred and forty-four patients with Tourette syndrome were followed up at 3-month intervals; exacerbations of tics, obsessive-compulsive symptoms, and other psychiatric comorbidities were defined by a bootstrap procedure. The effect of new GAS infections and identification of new ABGA upon risk of exacerbation was assessed using logistic regression analysis.
  
  
  RESULTS
  Cross-sectionally, patients with Tourette syndrome exhibited a higher frequency of GAS infection (8% vs 2%; p=0.009), higher anti-streptolysin O (ASO) titres (246 [108-432] vs 125 [53-269]; p<0.001), and higher ABGA frequency (25% vs 8%; p<0.001) than the comparison group. On prospective analysis, ASO titres were persistently elevated in 57% of patients with Tourette syndrome; however, new infections or newly identified ABGA did not predict clinical exacerbations (all p>0.05).
  
  
  CONCLUSIONS
  Patients with Tourette syndrome might be more prone to GAS infections and develop stronger antibody responses to GAS, probably as a result of underlying immune dysregulation. New GAS infections are unlikely to exert, years after their onset, a major effect upon the severity of neuropsychiatric symptoms.
authors.affiliation: Department of Neurological and Psychiatric Sciences, University of Bari, Bari, Italy. davidemartino@virgilio.it
authors.forename: Davide
authors.initials: D
authors.lastname: Martino
authors.forename: Flavia
authors.initials: F
authors.lastname: Chiarotti
authors.forename: Maura
authors.initials: M
authors.lastname: Buttiglione
authors.forename: Francesco
authors.initials: F
authors.lastname: Cardona
authors.forename: Roberta
authors.initials: R
authors.lastname: Creti
authors.forename: Nardo
authors.initials: N
authors.lastname: Nardocci
authors.forename: Graziella
authors.initials: G
authors.lastname: Orefici
authors.forename: Edvige
authors.initials: E
authors.lastname: Veneselli
authors.forename: Renata
authors.initials: R
authors.lastname: Rizzo
mesh_terms: D001289:Attention Deficit Disorder with Hyperactivity / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D002658:Developmental Disabilities / Q000453:epidemiology*; D005260:Female; D006801:Humans; D007223:Infant; D007859:Learning Disabilities / Q000175:diagnosis / Q000209:etiology; D016015:Logistic Models; D008297:Male; D009771:Obsessive-Compulsive Disorder / Q000453:epidemiology; D011569:Psychiatric Status Rating Scales; D012720:Severity of Illness Index; D013290:Streptococcal Infections / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology*; D005879:Tourette Syndrome / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology*