AimTo investigate whether systemic or local (culprit artery) plasma alpha-defensin 1-3 (DEFA1-3) levels are associated with stable coronary artery disease (CAD) and acute ST-segment elevation myocardial infarction (STEMI).MethodsSystemic or local blood samples were obtained from 122 consecutive male subjects including no CAD (n=31) controls, stable CAD (n=44) and STEMI (n=47).Plasma DEFA1-3 levels were measured by ready-to-use solid-phase enzyme-linked immunosorbent assay (ELISA) based on the sandwich principle.ResultsSystemic DEFA1-3 in STEMI were increased compared with no CAD (p<0.05) and stable CAD (p<0.05), and systemic DEFA1-3 in stable CAD were higher than in no CAD (p<0.05).However, local and systemic levels of DEFA1-3 did not differ (p>0.05).Receiver operating characteristic (ROC) analysis revealed that the best cutoff value for systemic DEFA1-3 levels discriminating STEMI from no CAD and stable CAD was 136.3 μg/L with a sensitivity of 77.2%, a specificity of 66.7% and an area under the curve (AUC) of 0.717 (95%CI: 0.624 to 0.811, p=0.000).ConclusionSTEMI was associated with increased DEFA1-3 in systemic circulation.Future studies should be directed to their prognostic values for myocardial infarction.