The precise cause of
tic disorders and paediatric
obsessive-compulsive disorder (OCD) is unknown. In addition to genetic factors, autoimmunity may play a role, possibly as a sequela of preceding streptococcal throat
infections in susceptible children. Here we review the most recent findings, from July 2003 onwards, with regard to a possible relationship between
tics/OCD and autoimmunity. Evidence about an intriguing correlation between
streptococcal infections and
tic disorders and OCD is accumulating. Specific criteria have been outlined for paediatric autoimmune disorders associated with
streptococcal infections (PANDAS), but autoimmunity may also be involved in
tic disorders and/or OCD in general. Anti-basal ganglia auto-
antibodies are an important potential
indicator of autoimmunity. Although the lack of a standardized methodology makes comparisons of findings difficult, new data has emerged pointing to the possible involvement of specific auto-
antigens. Earlier findings of increased D8/17 B cell expression as a putative susceptibility marker could not be replicated, possibly due to instability of the D8/17-binding antibody. Although PANDAS patients have been reported to improve after therapeutic
plasma exchange, and
antibiotics may prevent
symptom exacerbations, immune-based treatments should not be routinely given. In future studies, demonstrating the pathogenetic significance of anti-basal ganglia
antibodies in animals is a major challenge to draw any firm conclusions about a role for autoimmunity. Future longitudinal studies should be aimed at assessing the precise relationship between
symptom exacerbations,
infections, and immune parameters, possibly along with gene expression profiles.