Increased titers of antibodies against streptococcal M12 and M19 proteins in patients with Tourette's syndrome

It has been suggested that a post-streptococcal autoimmune process may be i nvolved in the pathogenesis of a subgroup of children with ties and obsessi ve-compulsive symptoms (PANDAS). Elevated antibody titers against streptoco ccal antigens have also been described in adult patients suffering from Tou rette's syndrome (TS). In order to characterise further streptococcal antig ens, we focussed on M proteins. M proteins are a major virulence factor of group A streptococci and known to evoke an immunologic cross-reaction with diverse epitopes of human tissue including brain tissue. Therefore, antibod ies against M proteins may play a role in the pathophysiology of at least a subgroup of TS patients. Antibodies against M proteins were studied in 25 adult patients suffering from TS and 25 healthy controls after careful medi cal examination. The antibody titers against the peptides MI, M4, M6, M12 a nd M19 were estimated by ELISA. Our results show increased titers of antibo dies against the streptococcal M12 and M19 proteins in TS patients as compa red with controls, while antibody titers against M1, M3 and M6 did not diff er between the TS and control groups. Elevated serum titers of antibodies a gainst M12 and M19 proteins support the view that a streptococcus-induced a utoimmune process may be involved in TS. The finding of a possible autoimmu ne origin of TS has implications for both pathophysiology and future therap eutic strategies. (C) 2001 Elsevier Science Ireland Ltd. All rights reserve d.