Deficiency of peripheral CLA⁺ Tregs and clinical relevance in Behcet’s syndrome

Autoimmune responses have been suggested to involvement in patients with Behcet’s syndrome (BS). There has been growing attention towards the roles of cutaneous lymphocyte antigen (CLA)⁺ regular T cells (Tregs) in autoimmune diseases. The role of CLA⁺ Tregs in BS is still uncertain. This study aims to clarify the impact of CLA⁺ Tregs on BS.

We collected peripheral blood from a total of 107 patients with BS and 114 healthy controls (HCs). The number of CLA⁺ Tregs, natural killer (NK) cells, B cells, and several subtypes of CD4⁺ T cells were detected using flow cytometry and compared between patients and HCs.

The absolute number and proportion of CLA⁺ Tregs among CD4⁺ T lymphocytes and CD4⁺ Tregs were lower in patients with BS than in HCs. CLA⁺ Tregs were positively related with NK cells (r = 0.500, P < 0.001) and B cells (r = 0.470, P < 0.001) and negatively related with effector T cells (r=-0.402, P < 0.001) in patients with BS. Patients with BS and arterial aneurysms had CLA⁺ Treg cell deficiency. A decreased proportion of CLA⁺ Tregs was associated with arterial aneurysms in patients with BS. The proportion of CLA⁺ Tregs in patients with BS increased with corticosteroids and immunosuppressants.

CLA⁺ Tregs decrease in association with arterial aneurysm in patients with BS. CLA⁺ Tregs may be a predictor of response to BS treatment.