Leukocyte depletion attenuates expression of neutrophil adhesion molecules during cardiopulmonary bypass in human beings

Background: On the basis of scanty information, the effects of a leukocyte filter during cardiac operations in human beings have been examined from the viewpoint of the expression of neutrophil adhesion molecules. This study was therefore designed to determine whether leukocyte depletion during cardiopulmonary bypass may interfere with neutrophil adhesion properties. Methods: Twenty-four patients undergoing elective heart operations were randomly allocated to a leukocyte-depletion group or a control group. Blood samples were collected at 7 points: before sternotomy, at 10, 30, and 60 minutes of cardiopulmonary bypass, at termination of cardiopulmonary bypass, 5 minutes after protamine administration, and 2 hours after cardiopulmonary bypass. The expression of the neutrophil surface adhesion molecules L-selectin and beta(2)-integrins was determined by flow cytometric analysis in whole blood. Results: (1) CD11a expression did not change significantly in either group. There were no significant differences between control and leukocyte-depletion groups (P = .63). (2) There was a significantly higher expression of CD11b on the neutrophils during cardiopulmonary bypass in the control group than in the leukocyte-depletion group (P = .01). (3) CD11c expression was initially up-regulated from the onset of cardiopulmonary bypass, reaching a peak at 60 minutes after bypass in the control group (P = .02). The expression of CD11c did not differ significantly between groups (P = .23). (4) L-selectin expression was significantly lower in the leukocyte-depletion group than in the control group (P = .03). Conclusions: The major findings of the present study in human subjects undergoing elective cardiac operations with cardiopulmonary bypass are as follows: (1) bypass was associated with an up-regulation of the adhesion molecules L-selectin, CD11b, and CD11c but with no significant change in CD11a expression, and (2) the clinical use of a leukocyte-depleting filter could down-regulate the expression of CD11b and L-selectin.