Gemma Eftimiadi, Costantino Eftimiadi, Piergiuseppe Vinai and Mauro Porta
Study Group of the Movement Disorders and Behavioral Child, GNOSIS Non Profit Research Organization, Carrù CN, Italy
Dopamine is a crucial neurotransmitter in motor control, and autoimmunity against its neuronal receptors may alter central dopamine pathways leading to movement and neuropsychiatric disorders, especially in childhood. In this study, we report a clinical improvement in tic frequency and severity during Staphylococcus aureus nasopharyngeal colonization in a girl with a chronic motor tic disorder. The clinical improvement in this intermittent S. aureus nasal carrier was associated with down-regulation of auto-antibody production against D1 and D2 dopamine receptors. Based on these findings, we suggest the existence of a cause-and-effect relationship between S. aureus colonization, immunomodulating activity, and motor tic improvement. Protein A, a recognized staphylococcal virulence factor involved in the bacterial colonization process, is capable of inducing strong immunodepression of host defenses. For this reason, protein A has been proposed for use as an immunosuppressive drug in the therapeutic management of autoimmune human diseases such as thrombotic thrombocytopenic purpura and rheumatoid arthritis, and is currently under investigation by others in a phase I/II clinical trial. The beneficial immunomodulation observed by us during S. aureus colonization opens the prospect of investigating the potential of staphylococcal protein A therapy as an innovative approach for treating autoimmune neuropsychiatric and movement disorders.
Keywords: Protein A, Staphylococcus aureus, Tourette syndrome, Autoimmunity, Movement Disorders, Dopamine, Dopamine receptors.