Post-streptococcal autoimmune disorders of the central nervous system.

PURPOSE OF REVIEW Autoimmune disease has long been intertwined with investigations of infectious causes. Antibodies that are formed against an infectious agent can, through the process of molecular mimicry, also recognize healthy cells. When this occurs, the immune system erroneously destroys the healthy cells causing autoimmune disease in addition to appropriately destroying the offending infectious agent and attenuating the infectious process. The first infectious agent shown to cause a post-infectious autoimmune disorder in the central nervous system was Streptococcus pyogenes in Sydenham's chorea. The present review summarizes the most recent published findings of central nervous system diseases that have evidence of a post-streptococcal autoimmune etiology. RECENT FINDINGS Sydenham's chorea and other central nervous system illnesses that are hypothesized to have a post-streptococcal autoimmune etiology appear to arise from targeted dysfunction of the basal ganglia. PANDAS (pediatric autoimmune disorders associated with streptococcal infections) is the acronym applied to a subgroup of children with obsessive-compulsive disorder or tic disorders occurring in association with streptococcal infections. In addition, there are recent reports of dystonia, chorea encephalopathy, and dystonic choreoathetosis occurring as sequelae of streptococcal infection. Investigators have begun to isolate and describe antistreptococcal-antineuronal antibodies as well as possible genetic markers in patients who are susceptible to these illnesses. SUMMARY Clinical and research findings in both immunology and neuropsychiatry have established the existence of post-streptococcal neuropsychiatric disorders and are beginning to shed light on possible pathobiologic processes.