At the time of this study, one proposed method by which PANDAS/PANS takes hold in patients is the autoimmune response of antibodies made to fight Group A beta-hemolytic Streptococcus (GABHS; a bacterium responsible for strep throat), which end up targeting brain regions relevant to OCD symptoms, such as the striatum (a part of the basal ganglia that is linked to movement and reward).
This study by Dr. Frick and her team aimed to further examine whether antibodies from people with PANDAS interact with neurons in the striatum, by taking the blood sera of five children with PANDAS and five healthy controls and infusing it into the striatum of mice. The study found that antibodies related to PANDAS did attach themselves to the striata of mice, and that symptoms in mice improved after the administration of intravenous immunoglobulin (IVIG; a mixture of antibodies that strengthen the immune system against autoimmune conditions. This treatment has shown efficacy in treating children with PANDAS.). This study demonstrated that PANDAS antibodies target the striatum, and that this reaction can resolve in mice after IVIG.
*Frick, L., Rapanelli, M., Jindachomthong, K., Grant, P., Leckman, J.F., Swedo, S., Williams, K., & Pittenger, C. (2018). Differential binding of antibodies in PANDAS patients to cholinergic interneurons in the striatum. Brain, Behavior, and Immunity, 69, 304-311. doi:10.1016/j.bbi.2017.12.004