Some studies have suggested that an infection with the streptococcus bacterium that causes sore throat in children may lead to the development of Tourette Syndrome symptoms (TS) in some children. In this group of children, it is postulated that the immune response originally mounted by the body to kill the bacteria may remain activated even after the bacteria have been eliminated from the body. These antibodies may then bind to specific tissues in the body and cause an inflammation in that organ. In the case of TS, the affected tissue is believed to be certain brain areas. In our project, we are investigating whether the immune system of children with TS differs from those who do not have TS. Our major focus is on the number of T lymphocytes (a type of white blood cell) and the level of immunoglobulins (Ig) in the blood of children with TS. Preliminary data obtained from our first year of TSA funding suggested that people with TS have T lymphocytes that are more responsive to streptococcal antigens, and that they have lower levels of IgA antibodies in their blood, compared to those without TS. These results suggest that the early stages of an immune response against streptococcal infection may be altered in people with TS, and that this results in a modified T cell response. In the current study we plan to isolate T lymph-ocytes from the blood of children with TS and investigate the function and gene-expression profile of these cells. An understanding of the involvement of the immune system in the development of TS may lead to new treatment options for people with the disorder. Ivana Kawikova, M.D., Ph.D., Alfred L.M. Bothwell, Ph.D., James Leckman, M.D. Yale School of Medicine, New Haven, CT Award: $75,000 (2nd Year) Tourette Association of America Inc. – Research Grant Award 2008-2009