Background : Recent studies have implicated inflammation in the pathogenesis of coronary artery disease. Statins are believed to reduce coronary heart disease by mechanisms in addition to their well-known cholesterol lowering effect. We studied the effect of statins on expression of C-reactive protein (CRP), interleukin-6 (IL-6), adhesion molecules, and oxidized low-density lipoprotein antibody (anti-oxLDL Ab) in patients with unstable angina (Braunwald class IIb or IIIb) undergoing coronary stenting. Methods : Consecutive 50 patients with unstable angina were included in this study. We classified the study subjects as patients using statins (Group A, n=20, male 10, mean age 62 years) and patients not using statins (Group B, n=30, male 15, mean age 60 years). Results : Baseline levels of inflammatory markers were no different in the two groups. However, 24 hours after coronary stenting, serum levels of CRP (2.00 vs. 4.63 mg/L, p<0.05), ICAM-1 (217짹70 vs. 261짹62 ng/ml, p<0.05), and anti-oxLDL Ab (8.9짹3.9 vs. 12.9짹6.9 U/ml, p<0.05) were significantly higher in the group B than group A. Also, 72 hours after coronary stenting, serum levels of CRP (3.0 vs. 5.50 mg/L, p<0.01) and ICAM-1 (222짹50 vs. 277짹71 ng/ml, p<0.05) were significantly higher in the group B than group A. In group B (no-statin group), CRP and anti-oxLDL Ab were increased significantly 24 hours after coronary stenting from the baseline value of 2.1 mg/L and 7.9 U/ml to 4.63 mg/L and 12.9 U/ml, p<0.05, respectively. At 24 hours after coronary stenting, CRP levels were elevated (median, >4.6 mg/L) in 4 (20%) of 20 patients of group A but in 17 (57%) of 30 patients of group B (p<0.05) and anti-oxLDL Ab levels were also elevated (mean, >11.2 U/ml) in 3 (15%) of 20 patients of group A but 14 (47%) of 30 patients of group B (p<0.05). Conclusions : Pre-existing statin therapy may play a role in reducing the serum levels of CRP, ICAM-1, and anti-oxLDL Ab after coronary stenting in patients with unstable angina. Theses data support an anti-inflammatory (or plaque stabilizing) effect of statin therapy.