Circadian Variation In CD40-CD40L System In Patients With Acute Coronary Syndrome

Objective: Clinical research indicates that there is significant circadian variation of ischemic events in acute coronary syndrome (ACS) , especially in acute myocardial infarction(AMI).The objective of this study is to determine whether there is a significant circadian variation of CD40 antigens and CD40 ligands (CD40Ls)on platelets in patients with ACS.Methods: The expression of CD40 and CD40L on platelets at 5A.M. and 10A.M. were determined in patients with unstable angina (n=40), patients with AMI (n=30) and in controls(n=40) by flow cytometry.Results: Expression of CD40 and CD40L on platelets in unstable angina(UA) and AMI patients were significantly higher than in controls(p<0.01).CD40L levels at 5 A.M. in patients with UA and AMI significantly increased compared to the levels at 10A.M. (p<0.001) . But in controls,expression of CD40L on platelets has no significant difference between 5A.M. and 10A.M. (p>0.05). CD40 expression on platelets at 5A.M. was higher than the levels at 10A.M.,but there is not significant difference between controls and patients with ACS(p>0.05) .Conclusion: Patients with ACS show significantly increased coexpression of CD40 system and circadian variation at CD40L concentration on platelets.It demonstrates that CD40 system...