Off-pump coronary artery bypass grafting does not reduce lymphocyte activation

Objective In this study, we test the hypothesis that off-pump coronary bypass surgery might result in less lymphocyte activation than on-pump coronary surgery. We also study the behavior of lymphocyte activation markers during and after surgery. Background Coronary artery bypass surgery is known to be associated with changes of inflammatory mediators, immune function, and early phase lymphocyte activation, which could cause postoperative lymphopenia and lymphocyte unresponsiveness. Methods We studied lymphocyte activation response in 28 patients randomized to off-pump (n=13) or on-pump (n=15) coronary artery bypass surgery. Expression of CD25, CD26, CD69, and DR on T (CD3+) and B (CD19+) lymphocytes on peripheral blood was assessed through flow cytometry. Results The response of T lymphocytes and their activation markers, as well as B lymphocytes and their activation markers, was similar after on- and off-pump surgery. Overall, T lymphocytes decreased to the lowest level 9 h after surgery and tended to increase later. For B lymphocytes, there was early reduction with increase on the 1st postoperative day. There was early activation of CD69+ and late activation of CD25+ on T lymphocytes. For B lymphocytes, there was early activation of CD69+ and late activation of DR+. Conclusions (1) Compared to on-pump cardiopulmonary bypass, off-pump surgery does not reduce lymphocyte activation. (2) Coronary bypass surgery causes the early activation of lymphocytes, as evidenced by the increased expression of lymphocyte activation markers.