Pro-inflammatory dopamine-2 receptor-specific T cells in paediatric movement and psychiatric disorders

Dopamine receptor autoantibody signaling in infectious sequelae differentiates movement versus neuropsychiatric disorders

Despite growing recognition, neuropsychiatric diseases associated with infections are a major unsolved problem worldwide. Group A streptococcal (GAS) infections can cause autoimmune sequelae characterized by movement disorders, such as Sydenham chorea, and neuropsychiatric disorders. The molecular mechanisms underlying these diseases are not fully understood. Our previous work demonstrates that autoantibodies (AAbs) can target dopaminergic neurons and increase dopamine D2 receptor (D2R) signaling. However, AAb influence on dopamine D1 receptor (D1R) activity is underexplored. We found evidence that suggests GAS-induced cross-reactive AAbs promote autoimmune encephalitis of the basal ganglia, a region of high dopamine receptor density. Here, we report a mechanism whereby neuropsychiatric syndromes are distinguished from movement disorders by differences in D1R and D2R AAb titers, signaling, receiver operating characteristic curves, and immunoreactivity with D1R and D2R autoreactive epitopes. D1R AAb signaling was observed through patient serum AAbs and novel patient-derived monoclonal antibodies (mAbs), which induced both D1R G protein- and β-arrestin-transduced signals. Furthermore, patient AAbs and mAbs enhanced D1R signaling mechanisms mediated by the neurotransmitter dopamine. Our findings suggest that AAb-mediated D1R signaling may contribute to the pathogenesis of neuropsychiatric sequelae and inform new options for diagnosis and treatment of GAS sequelae and related disorders.

Cytokine profile of pediatric patients with obsessive-compulsive and/or movement disorder symptoms: A review

Cytokines are an important modulator of the immune system and have been found to be altered significantly in many neurological and psychiatric disorders, like obsessive compulsive disorder (OCD) and movement disorders. Also, in pediatric autoimmune neuropsychiatric disorders associated with group A streptococcal infections (PANDAS), which are characterized by abrupt debut of symptoms of OCD and /or movement disorder symptoms, alterations in the immune system have been suggested. The aim of this paper was to review the current literature on the cytokine profile of pediatric patients with symptoms of OCD and/or movement disorder symptoms. A search of PubMed and Medline was performed with specific keywords to review studies measuring cytokines in pediatric patients with symptoms of OCD and/or movement disorders. Nineteen studies were found, twelve of which included a healthy control group, while four studies had control groups of children with other disorders, primarily neurological or psychiatric. One study compared cytokines measurements to reference intervals, and two studies had a longitudinal design. Many cytokines were found to have significant changes in patients with symptoms of OCD and/or movement disorders compared to both healthy controls and other control groups. Furthermore, differences were found when comparing cytokines in periods of exacerbation with periods of remission of symptoms in study participants. The cytokines that most studies with healthy control groups found to be significantly altered were TNF-α, IL-1β and IL-17. Although the exact role of these cytokines in OCD and movement disorder symptoms remains unclear, the available literature suggests a proinflammatory cytokine profile. This offers interesting perspectives on the pathogenesis of OCD and/or movement disorder symptoms in children, and further research into the implications of cytokines in neuropsychiatric disorders is warranted.