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The imbalance of CD4(+)CD25(+) regulatory T (Treg) cells and Th17 cells has shown to be involved in pathogenesis of atherosclerosis and acute coronary syndrome [ACS, including unstable angina (UA) and acute myocardial infarction (AMI)]. The purpose of this study is to explore the significance of Treg/Th17 ratio in early diagnosis for ACS. We detected expression of Treg and Th17 in patients with AMI, UA, stable angina, and subjects with normal coronary arteries at the time of admission. Our results showed that ACS patients have a significant increase of Th17 number, but a marked decline of Treg/Th17 ratio, Treg number, and Treg function. Significant positive correlations in Th17 frequency and negative correlation in Treg frequency, Treg/Th17 ratio were found to levels of oxidized low-density lipoprotein (Ox-LDL), high sensitive C-reactive protein (hsCRP), Lipoprotein (a) [Lp(a)], and Creatine kinase-MB(mass) (CK-MBmass) in serum. Receiver-operating characteristic curves shown that the predictive specificity and sensitivity of Treg/Th17 ratio for ACS and AMI was the highest among all the five markers: Ox-LDL, hsCRP, Lp(a), CK-MBmass, and Treg/Th17 ratio. In conclusion, Treg/Th17 ratio appeared to be a novel indicator for early diagnosis of ACS.

Objective: An imbalance in CD4(+)CD25(+) regulatory T (Treg) cells and Th17 cells has been found to correlate to occurrence of acute coronary syndrome [ACS, including unstable angina (UA) and acute myocardial infarction (AMI)]. However, the mechanisms of Th17/Treg imbalance in ACS patients are still unclear. The purpose of this study is to investigate the possibility of differences in sensitivity of Th17 and Tregs to Fas-mediated apoptosis which could lead to Th17/Treg imbalance in ACS patients., Methods: We examined the apoptosis of Th17 and Treg cells, apoptosis-related Fas/Fas ligand(FasL) pathway, and inflammatory markers in patients with AMI, UA, stable angina (SA) and controls by Flow cytometry and ELISA. Then we analysed the correlation of inflammatory markers and sFasL to Treg apoptosis, and the effect of anti-FasL antibody on Treg apoptois in vitro., Results: Our study demonstrated that apoptotic Tregs, Fas and FasL expression, Caspase-3 activity of Tregs were significantly higher in ACS patients than those in NCA and SA patients (all P < 0.05). The percentage of apoptotic Tregs is positively correlated with the levels of inflammatory markers and sFasL. In vitro incubation of peripheral blood mononuclear cells from ACS patients with anti-FasL antibody resulted in a markedly reduction of apoptotic Treg cells. However, there were no significant differences in apoptotic Th17 cells and in Fas and FasL expression for Th17 cells between the four groups (all P >0.05)., Conclusions: Tregs, but not Th17 cells, become apoptotic through Fas/FasL pathway, which contributed to reduction of Tregs leading to an imbalance between Th17 and Treg cells. This could be the mechanism underlying Th17/Treg imbalance and occurrence of ACS.

Oxidized low-density lipoprotein (ox-LDL) is an instrumental factor in atherogenesis, however, the effects of ox-LDL on the balance of Th17/Treg in acute coronary syndrome [ACS, including unstable angina (UA) and acute myocardial infarction (AMI)] is still unclear. CD4(+)CD25(+) regulatory T (Treg) cells and Th17 cells, subsets of T-helper cells, play important roles in peripheral immunity and their imbalance leads to the development of tissue inflammation and autoimmune diseases. However, few studies have explored the effect of Th17/Treg balance in plaque destabilization and the onset of ACS. To explore the shift of Th17/Treg balance in ACS patients and the effect of ox-LDL on the balance, we examined the frequencies of Th17 and Treg cells, key transcription factors and relevant cytokines in patients with AMI, UA, stable angina (SA) and controls. We analysed the correlations of serum ox-LDL to Th17/Treg frequency, and the effects of ox-LDL on Th17/Treg cells in vitro. Our study demonstrated that ACS patients have shown a significant increase of Th17 frequency, RORgammat expression and serum Interleukin 17 (IL-17), and a obvious decline of Treg frequency, Foxp3 expression, suppressive function, and serum IL-10. Serum ox-LDL positively correlated with the frequency of Th17 cells and negatively correlated with the frequency of Treg cells. In vitro incubation of peripheral blood mononuclear cells from controls with ox-LDL resulted in a significant reduction of Treg cells and a significant elevation of Th17 cells in a dose- and time-dependant manner. Treg and Th17 cells from ACS patients were significantly more susceptible to ox-LDL-mediated alterations. Th17/Treg numerical and functional imbalance exists in ACS patients, and ox-LDL has a direct effect on Th17/Treg imbalance which may contribute to the occurrence of ACS., (Copyright 2010 Elsevier Inc. All rights reserved.)