Anti-basal ganglia antibodies in PANDAS

An autoimmune-mediated mechanism involving molecular mimicry has been proposed for a variety of pediatric movement disorders that occur after a streptococcal infection. In this study, anti-basal ganglia antibodies (ABGA) were measured in 15 children with the diagnosis of pediatric autoimmune neuropsychiatric disorder associated with streptococcal infection (PANDAS) and compared with those in 15 controls. ELISA and Western immunoblotting (WB) methods were used to detect ABGA against supernatant (S1), pellet (P2), and synaptosomal preparations from adult postmortem caudate, putamen, and globus pallidus. ELISA optical density values did not differ between PANDAS patients and controls across all preparations. Immunoblotting identified multiple bands in all subjects with no differences in the number of bands or their total density. Discriminant analysis, used to assess mean binding patterns, showed that PANDAS patients differed from controls only for the caudate S1 fraction (Wilks' lambda = 0.0236, P < 0.0002), with PANDAS-primarily tic subjects providing the greatest discrimination. Among the epitopes contributing to differences between PANDAS and control in the caudate S1 fraction, mean binding to the epitope at 183 kDa was the most different between groups. In conclusion, ELISA measurements do not differentiate between PANDAS and controls, suggesting a lack of major antibody changes in this disorder. Further immunoblot analyses using a caudate supernatant fraction are required to completely exclude the possibility of minor antibody repertoire differences in PANDAS subjects, especially in those who primarily have tics.