ABSTRACT
<p><b>OBJECTIVE</b>To explore the changes in T helper lymphocytes and their subsets in children with tic disorders (TD) and their clinical significance.</p><p><b>METHODS</b>Flow cytometry was used to measure the percentages of T helper lymphocytes and their subsets in the peripheral blood of children with TD and healthy children (controls).</p><p><b>RESULTS</b>The percentage of T helper lymphocytes was significantly lower in the TD group than in the control group (P<0.001). The abnormal rate of T helper lymphocytes in the TD group was significantly higher than that in the control group (68.7% vs 18.8%; P<0.001). The percentage of T helper lymphocytes was negatively correlated with Yale Global Tic Severity Scale score (r=-0.3945, P<0.001). As for the subsets of T helper lymphocytes, the TD group had a significantly higher percentage of Th1 cells and a significantly lower percentage of Th2 cells compared with the control group (P<0.001).</p><p><b>CONCLUSIONS</b>The abnormality of T helper lymphocytes and the imbalance of their subsets may be associated with the pathogenesis of TD in children. The percentage of T helper lymphocytes can be used as an indicator for assessing the severity of TD.</p>