Regulatory T Lymphocyte Subpopulations in the Early Stages of Carotid Artery Stenosis

The aim of this study was to evaluate the CD4+ CD25+ and LAG3+ regulatory T lymphocyte subpopulations in patients with traditional cardiovascular risk factors and increased values of intima media thickness (IMT). Based on Doppler ultrasound, 41 patients with traditional cardiovascular risk factors were divided into two groups: group H-IMT (high-intima medial thickness) including 22 subjects with intima medial thickness (IMT) 1.0 mm and group L-IMT (low-intima medial thickness) including 19 patients with IMT 1.0 mm. Considering blood pressure values, two further groups were selected: group H-IMT/AH including 13 patients by arterial hypertension (AH) with IMT values 1.0 mm and group RF (risk factors) including 10 patients with normal blood pressure values and IMT 1.0 mm. Frequencies of T CD4+, T helper 17 (Th17), regulatory T CD4+ CD25+ (Tregs) and Lag3+ (LAG3 + Tregs) lymphocyte subpopulations were evaluated. A p value 0.05 was considered significant. Our results showed that Tregs and Treg/T17 ratio were significantly reduced in the H-IMT group compared with the L-IMT group (p 0.0093 and p 0.0047, respectively). Furthermore, in the HIMT/AH group, LAG3+ Tregs were significantly increased (p 0.0378) and CD4+ CD25+ Tregs significantly reduced (p 0.04398). We therefore would suggest that in patients with traditional cardiovascular risk factors, the reduction of regulatory T lymphocyte subpopulations can favour the progression of atherosclerotic disease. In this context, the increase in Lag3+ Tregs observed in hypertensive patients showing higher IMT values suggests that inflammation may induce the expression of LAG on Tregs, amplifying the pro-inflammatory mechanisms that induce carotid plaque formation.