HMG-CoA reductase inhibitors (statins) reduce cardiovascular mortality and morbidity in patients with stable coronary artery disease as well as acute coronary syndrome (ACS). It is unclear how rapidly the beneficial effects of statins occur in patients with ACS and whether these drug properties are related to lipid lowering. Patients with troponin-positive ACS (n=35) were randomized to 20 mg/day rosuvastatin therapy or to placebo treatment. Anti-inflammatory effects of rosuvastatin measured by lymphocyte intracellular cytokine production were taken before initiation of treatment and on days 1, 3, and 42. Compared with placebo, rosuvastatin treatment significantly reduced plasma concentrations of pro-inflammatory cytokines TNF-alpha and IFN-gamma at 72 h. Rosuvastatin also induced a rapid and significant reduction of TNF-alpha and IFN-gamma production in stimulated T-lymphocytes at 72 h. When compared with placebo, rosuvastatin inhibited the Th-1-immune response measured at 72 h. Rosuvastatin exerts rapid immunomodulatory effects on the level of T-cell activation in patients with ACS.