AimTo expore the effect of hyperinsulin on the maturation of monocyte-derived dendritic cells in the Acute Coronary Syndrome(ACS) patients.MethodsHuman monocytes of ACS were purifed using successive adherence method, recombinated human granulocyte-macrophage colony stimulating factor （GM-CSF,100 μg/L）and interleukin-4（IL-4,100 μg/L）after 5 days culture in RPMI 1640 medium containing. Immature DC (imDC) were collected, then added RPMI 1640 medium containing with insulin of various concentrations(1nmol/L, 10nmol/L,100 nmol/L)for 48 hours, mature DC (mDC) were derived. Immunophenotypic expression of CD40, CD80 and CD83 were monitored by flow cytometry, and expression of IL-12, IL-10 and TNF-α were measured by ELISA,and the morphological features of dendritic cells were observed with invert optical microscope. ResultsHyperinsulin promoted the expression of CD40, CD80 and CD83 and enhanced the expression of IL-12 and TNF-α significantly and refained the expression of IL-10 in the acute coronary syndrome patients. ConclusionsHyperinsulin contributed to the development of atherosclerosis via stimulating immune maturation of DC，which may be one of its mechanisms in the development of ACS.