Flow Cytometric Evaluation of T Cell Activation Markers after Cardiopulmonary Bypass

Abstract EN

Background.

Cardiopulmonary bypass surgery (CPBS) is associated with an increased risk for infections or with subsequent organ dysfunction.

As T cell activation is a central mechanism during inflammatory processes, we developed an assay to evaluate T cell activation pathways in patients undergoing CPBS.

Methods.

Blood was obtained from eleven patients undergoing CPBS preoperatively, on postoperative day (POD)-3, and on POD-7 and was stimulated with different concentrations of Concanavalin A (ConA).

Cyclosporine and sirolimus, inhibiting different pathways of the T cell cycle, were added to blood ex vivo.

Expression of T cell activation markers CD25 and CD95 was analyzed by flow cytometry.

Results.

In untreated blood, expression of CD25 and CD95 significantly increased with higher ConA concentrations (P<0.05) and decreased for all ConA concentrations for both antigens over the study time (P<0.05).

Independently from the ConA concentration, inhibition of CD25 and CD95 expression was highest preoperatively for sirolimus and on POD-3 for cyclosporine.

At all time points, inhibition of CD25 and CD95 expression was significantly higher after cyclosporine compared to sirolimus treatment (P<0.001).

Conclusion.

Our results showed that different pathways of T cell activation are impaired after CPBS.

Such knowledge may offer the opportunity to identify patients at risk for postoperative complications.