An examination of the relationship between regulatory T cells and symptom flare-ups in children and adolescents diagnosed with chronic tic disorder and Tourette syndrome.

Background: Tourette syndrome (TS) is a childhood-onset neurodevelopmental disorder characterized by several motor and phonic tics.

Aims: In this study, we aimed to compare activated regulatory T cell (Treg) values between patients with TS/chronic tic disorder (CTD) and age- and sex-matched healthy controls (HCs).

Materials And Method: Patients with TS/CTD and age- and sex-matched HCs were included in the study. The severity of the disease was evaluated using the Yale Global Tic Severity Scale. CD4CD25CD127 Tregs from the patient group and the control group were compared using flow cytometry.

Results: The study included 48 patients diagnosed with TS/CTD (36 males and 12 females, mean age: 11.58 ± 2.61) and 24 HCs (18 males and 6 females, mean age: 11.63 ± 2.60). The TS/CTD group had significantly higher activated regulatory T percentile with respect to the T helper value compared to the HCs ( 0.010). Lymphocyte count, T lymphocyte count, T lymphocyte percentage, T-helper lymphocyte count, and T-helper lymphocyte percentage were lower in the patient group compared to the control group ( 0.024, 0.003, 0.007, <0.001, <0.001, respectively). The comparison of three groups (mild, moderate-severe, and HCs) revealed that T lymphocyte number and percentage and the T helper number and percentage were significantly higher in the HC group compared to the moderate-severe group, whereas the activated Treg percentage with respect to the T helper value was significantly higher in the moderate-severe group compared to the HC group (0.002, 0.026, <0.001, <0.001, 0.027, respectively).

Conclusion: Our results suggest that Tregs may have a role in the pathogenesis of TS/CTD.