Changes of CD4^＋CD25^＋ Regulatory T Cells in Patients with Acute Coronary Syndrome and the Effects of Atorvastatin

The function of CD4＋CD25＋ regulatory T lymphocytes （Treg） in patients with acute coronary syndrome （ACS） and the effects of atorvastatin were investigated. Forty-eight patients with ACS were randomly divided into two groups： group C receiving conventional therapy （n=24）, and group C＋A receiving conventional therapy＋atorvastatin （10 mg/day, n=24）. T lymphocytes from ACS patients （before and 2 weeks after the treatment） or 18 healthy subjects were separated and the flow cytometry was used to measure the percentage of Treg. The inhibitory ability of Treg on effector T cells was determined by mixed lymphocyte reaction （MLR）. ELISA was used to measure the serum levels of cytokines （IL-10, TGF-β1 and IFN-γ） before and after treatment. The results showed that as compared with normal control group, Treg percentage was decreased significantly （P〈0.01）, the inhibitory ability of Treg on the T lymphocytes proliferation was reduced （P〈0.01）, IFN-γ levels were increased and IL-10 and TGF-β1 levels were lowered in ACS patients. After treatment with atorvastatin, Treg percentage and the inhibitory ability of Treg on T lymphocytes proliferation were significantly increased in ACS patients. Serum IFN-γ was decreased significantly, while IL-10 and TGF-β1 were elevated significantly as compared with the non-atorvastatin group. The number of Treg was positively correlated with serum TGF-β1, but negatively with serum IFN-γ and CRP. It was concluded that ACS was associated with decreased number and defected function of Treg, which may play an important role in initiating immune-inflammatory response in ACS. The inhibitory effects of atorvastatin on inflammation in ACS may be due to its beneficial effects on Treg and restoration of immune homeostasis.