The effect of cardiopulmonary bypass in the expression of CD40 ligand on platelet membrane

Objective To observe the effect of cardiopulmonary bypass(CPB)in the expression of CD40 ligand (CD40L) on platelets membrane,and to investigate the correlation between platelet stimulation,systemic inflammation and coagulation.Methods 40 patients undergoing open heart operation by CPB were studied.Blood samples were collected from peripheral arterial 10 minutes after anesthesia induction(T1),30 minutes after CPB(T2),instant on the termination of CPB(T3),after 2 hours(T4),4 hours(T5),8 hours and at the termination of CPB(T6).The expression of CD40L and CD62P on platelet membrane,plasma TNF-α concentration,total amount of bleeding after 24-hour CPB were detected.Results The expression levels of CD40L on platelet membrane were significantly increased after CPB(P0.01),which reached its peak at the termination of CPB and returned to the baseline after 8 hours.The CD40L was significantly correlated with CD62P,TNF-α and the amount of bleeding respectively(P0.01).Conclusion The expression of CD40L on platelet membrane increases with the platelet-activation caused by CPB.The platelet-derived CD40L may be involved in both the thrombotic and inflammatory events accompanied with CPB.