Levels of interleukin-33 and interleukin-6 in patients with acute coronary syndrome or stable angina.

Purpose: The purpose of this study was to investigate the levels of interleukin-33 (IL-33) and interleukin-6 (IL-6) in patients with acute coronary syndrome or stable angina. Methods: Serum IL-33 and IL-6 were measured with Enzyme Linked Immuosorbent Assay (ELISA) in patients with acute coronary syndrome (ACS, n = 40), and stable angina pectoris (SAP, n = 43). IL-33 and IL-6 were also determined in 30 healthy subjects (control group). Results: The serum level of IL-33 in the ACS group (78.60 +/- 44.84 ng/L) was lower than in the SAP (102.58 +/- 37.21 ng/L, P<0.01) or control groups (130.24 +/- 10.17 ng/L, P<0.01). The serum level of IL-6 in the ACS group (39.90 +/- 12.64 ng/L) was higher than in the SAP (18.68 +/- 11.89 ng/L, P<0.05) or control groups (6.28 +/- 17.72 ng/L, P<0.05). There were no differences in serum levels of IL-33 and IL-6 among the single-, double-and triple-vessel lesion groups. IL-33 and IL-6 levels were negatively correlated with each other in the ACS (r = -0.871, P<0.01) and SAP groups (r = -0.788, P<0.01). Conclusion: The serum level of IL-33 was lower in patients with ACS or SAP and was negatively correlated with the serum level of IL-6. Thus, IL-33 and IL-6 may be used as biomarkers for evaluating inflammatory response and severity of coronary heart disease in patients with ACS or SAP.