Relation between upregulation of CD40 system and complex stenosis morphology in patients with acute coronary syndrome.

Aim: To investigate whether upregulation of CD40-CD40 ligand system is related to matrix metalloproteinases level and stability of coronary atherosclerotic plaque in patients with acute coronary syndrome (ACS).

Methods: Sixteen normal controls and 56 patients including 24 with stable angina (SA), 20 with unstable angina (UA), and 12 with acute myocardial infarction (AMI) were investigated. The expression of CD40 and CD40L on platelet was analyzed by flow cytometry. Serum soluble CD40L (sCD40L), MMP-9 and MMP-3 level was determined by ELISA. All coronary stenosis with > or =30% diameter reduction were assessed by angiographic coronary stenosis morphology.

Results: Patients with ACS showed a significant increase of CD40 (75 +/- 12 MIF) and CD40L (13 +/- 4 MIF) coexpression on platelets compared with control and SA group (P<0.01). sCD40L also showed higher level in patients with ACS (10.2 +/- 3.5 microg/L) than in control (3.1 +/- 1.4 microg/L, P<0.01) and SA group (3.3 +/- 1.6 microg/L, P<0.01). Serum MMP-3 and MMP-9 in patients with ACS were two times greater than those in control. A positive correlation was found between MMP-9, MMP-3, and CD40L expression on platelets as well as sCD40L levels, but not for CD40 expression on platelets. An obvious correlation was also observed between sCD40L concentration and complex coronary stenoses (r=0.60, P<0.01).

Conclusion: Patients with ACS show increased coexpression of CD40 system, especially expression of CD40L, which may create a proinflammatory and prothrombotic milieu for aggravating the development of atherosclerosis and instability of atherosclerotic plaques, and may be a valuable marker for predicting the severity of ACS.