The role of immune dysfunction in the development of tics and susceptibility to infections in Tourette syndrome: A systematic review

Tourette syndrome (TS) is a neurodevelopmental disorder associated with motor and phonic tics. While the aetiology has been debated, no single causative agent has been implicated in the development of TS. This systematic review aims to evaluate original studies investigating the role of immunological abnormalities in both tic expression and susceptibility to infection in patients with TS. A comprehensive literature search using the databases 'EMBase', 'PsycInfo', 'Pubmed', 'Thomson World of Science' and 'Medline' generated 21 original studies that met inclusion criteria. Results found that abnormalities related to lymphocytes, cytokines, antineuronal antibodies and immunoglobulins were relatively common in TS populations. In addition, abnormalities in immunoglobulin concentrations could be linked to a propensity to the development of infections in selected individuals with TS. While these results support the initial research question, further studies with fewer confounding factors are required to establish a definite association between immune dysfunction, TS and infection.