ABSTRACT
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 autoimmune and inflammatory diseases. Quantitative and/or functional alteration of Tregs has been shown to play an atheroprotective role and may also promote plaque stabilization. To assess if inducible costimulatory molecule [ICOS] expression on one subtype of Treg cells with high suppressive potential correlates with the pathogenesis of atherosclerosis. 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. Peripheral blood mononuclear cells [PBMCs] were prepared and the expression of ICOS, Foxp3 and CD4 molecules was tested by flowcytometry. 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, respectivly]. 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