Expression of adhesion and activation molecules on lymphocytes during open-heart surgery with cardiopulmonary bypass.

Open-heart surgery with cardiopulmonary bypass (CPB) and abdominal surgery are associated with lymphocytopenia. We measured a panel of adhesion and activation molecules on lymphocytes to clarify possible association of CPB with increased expression of these molecules. Eight patients undergoing open-heart surgery and eight with abdominal surgery were studied. The adhesion molecules CD11a/CD18 (LFA-1_, CD11c/CD18 and CD44 and the activation molecules CD25, CD69, CD71 and MHCII were measured, using monoclonal antibodies and flow cytometry. Lymphocytopenia was observed during CPB and for some hours after both open-heart and abdominal surgery. The proportion of CD11a/CD18-positive lymphocytes rose from 67.6 +/- 8% to 86.4 +/- 3% after aortic declamping (p < 0.05). The expression of activation molecules CD25, CD69 and CD71 was unchanged during and after open-heart as well as abdominal operations. Thus CPB was associated with increased expression of the adhesion molecule CD11a/CD18 on lymphocytes, while the expression of activation molecules on lymphocytes was unchanged.