In addition, statistically significant positive correlation was found between high concentration of IL-8 at day 5 after PCI and the rate of unstable angina that developed during the follow-up period (7.96 ± 0.96 years) after primary STEMI (R = 0.5; p = 0.02) in control group. The gene discussed is CXCL8; the disease is angina unstable.