Background: The pro-inflammatory cytokine IL-18 has been suggested to play a role in atherogenesis and atheromatous plaque rupture leading to the acute coronary syndrome (ACS). Conversely, the anti-inflammatory cytokine IL-10 seems to have an atheroprotective role. Patients with unstable coronary artery disease show an imbalance between serum levels of pro- and anti-inflammatory cytokines, and studies have shown that IL-18/IL-10 ratio is an independent predictor of adverse in-hospital events in patients with ACS. We assessed the long-term prognostic significance of admission interleukin-18 (IL-18)/interleukin-10 (IL-10) ratio for recurrent coronary events during a 1-year follow-up in patients presenting with an ACS.
Methods: We assessed independent predictors of the combined end-point using multiple logistic regression analysis, in 186 patients (138 men, 65+/-12 years) with ACS (75 STEMI, 65 NSTEMI and 46 unstable angina). The composite of cardiac death and re-hospitalization with non-fatal myocardial infarction, or unstable angina, was the pre-specified study end-point. Serum IL-10 and IL-18 levels were measured at study entry using commercially available ELISAs.
Results: During the 1-year follow-up, 48 (26%) patients had recurrent cardiac events and 138 (74%) were event-free. IL-18/IL-10 ratio predicted the occurrence of adverse cardiac events (OR 1.91, 95% CI 1.37-2.65, p<0.001), and was found to be an independent predictor among other established biochemical and clinical risk markers (OR 2.31, 95% CI 1.55-3.42, p<0.001).
Conclusions: Serum IL-18/IL-10 ratio is an independent predictor of recurrent coronary events during long-term follow-up in patients presenting with ACS. Our study further supports the hypothesis that the balance between pro-inflammatory and anti-inflammatory cytokines may be an important determinant of patient outcome, suggesting a pathogenic role in plaque progression and instability.