CD4⁺Foxp3 ⁺ Treg and its ICOS ⁺ Subsets in Patients with Myocardial Infarction

Background: Atherosclerosis is a multifactorial disorder with chronic inflammatory conditions in which immune cells play a significant role in its pathogenic process. Regulatory T cells (Treg), as a part of immune system, are involved in controlling auto-immune and inflammatory diseases. Quantitative and/or functional alteration of Tregs has been shown to play an atheroprotective role and may also promote plaque stabiliza-tion. Objective: To assess if inducible costimulatory molecule (ICOS) expression on one subtype of Treg cells with high suppressive potential correlates with the pathogene-sis of atherosclerosis. Methods: Patients with myocardial infarction (MI) and/or stable angina (SA), diagnosed as atherosclerosis by angiography, and a group of individuals with normal coronary angiography (NCA) were recruited for the present study. Periph-eral blood mononuclear cells (PBMCs) were prepared and the expression of ICOS, Foxp3 and CD4 molecules was tested by flowcytometry. Results: The percentage of CD4+Foxp3+ Treg cells was reduced in MI group compared to NCA and SA groups (p<0.005). Evaluation of the two Treg subsets according to ICOS expression showed a decreased ICOS+/ICOS- Treg ratio in MI and SA groups compared to NCA individuals (p=0.002 and p=0.048, respectively). Conclusion: The present data indicate that Tregs and its ICOS+ subsets are decreased in patients with MI or SA, suggesting a potential role for Treg in atherosclerosis progression or onset of acute coronary syndrome