Regulatory T cells and IL-10 levels are reduced in patients with vulnerable coronary plaques

Background: Despite having a similar large extent of atherosclerotic coronary affliction, some patients suffer of recurrent cardiac events, whereas others remain asymptomatic. Hypothesis: We hypothesized the existence of a systemic "signature" that could distinguish "vulnerable" patients with preexisting coronary atherosclerosis from those having similar risk factors and atheromatous burden, but no history of clinically evident plaque rupture/erosion. Methods: Twenty three patients who had at least two prior myocardial infarctions ("vulnerable group") were matched in respect to their background and coronary atherosclerosis extent with twenty one patients without a history of previous myocardial infarction who underwent routine coronary angiography before valvular surgery. We studied a panel of cytokines, antibodies and hormones including IL-6, IL-10, IL-12, antibodies to beta 2 glycoprotein I (beta 2GPI), antibodies to oxidized-LDL, adiponectin and resistin, along with levels of circulating EPCs and Tregs. Results: A significantly higher level of Treg cells was present in the control (73.4% + 4) than in the "vulnerable patient" group (62.2% +/- 10.7), p<0.001. IL-10 level was also significantly higher in the control than in the vulnerable patients (2.6 +/- 1.2 pg/ml versus 0.9 +/- 0.1 pg/ml respectively, p = 0.03). There was no significant difference in the circulating levels of the other cytokines, hormones or EPCs between the two groups. Conclusion: Regulatory T cells and serum IL-10 may discriminate "vulnerable" versus stable patients and may have a protective role against plaque rupture in patients with coronary atherosclerosis. (C) 2012 Elsevier Ireland Ltd. All rights reserved.