Anti-brain antibodies in adult patients with obsessive-compulsive disorder

Background An autoimmune hypothesis has been suggested for a subtype of Obsessive–Compulsive Disorder (OCD) with childhood onset: obsessions, compulsions and/or tics would result from anti-streptococcal antibodies that cross-react with basal ganglia tissue based on molecular mimicry. Consistent with this hypothesis anti-brain antibodies were detected in sera of children with OCD and/or Tourette's syndrome. In the present study, we tested whether adults with OCD have anti-brain antibodies or other antibodies that serve as markers of autoimmunity. Methods Seventy-four DSM-IV OCD (YBOCS ≥ 16) subjects were recruited and compared to 44 controls with a current Major Depressive Episode for neurological symptoms, ALSO titres, anti-tissue and anti-thyroid antibodies. Anti-brain antibodies were tested by immunohistochemistry and Western blotting methods. Results The proportion of subjects with tic comorbidity or positive ASLO titre (> 200 IU/ml) was significantly greater in OCD than in MDE patients (21.6 vs. 2.3% and 16.3 vs. 2.3%, respectively). No other differences in antibody parameters were found. 4/74 OCD patients (5.4%) and none of the controls resulted positive for anti-brain antibodies, with a band around 50–60 kDa at the Western blot analysis. Limitations The methodology used to assess anti-brain antibodies. Conclusions The majority of adult OCD patients do not seem to have autoimmunity disturbances as compared to a control group. However, a greater percentage of subjects with positive ASLO titres were found among OCD patients. For a small proportion of OCD patients, moreover, autoimmune reactions towards neuronal structures are present although further investigations are needed to demonstrate its etiopathogenetic relevance.