Down-regulation of surface monocyte lipopolysaccharide-receptor CD14 in patients on cardiopulmonary bypass undergoing aorta-coronary bypass operation.
OBJECTIVE
Major operative trauma like aorta-coronary bypass operation may lead to postoperative immunodisturbance, putting the patient at an increased risk for infection and sepsis. The monocyte/macrophage system and the endotoxin receptor CD14 are important in the early recognition and elimination of invading bacteria. The aim of this study was to analyze changes in membrane-associated CD14 and soluble CD14 during and after cardiac involving cardiopulmonary bypass.


METHODS
We studied numbers of leukocytes, monocytes, and monocyte subpopulations, expression of monocyte membrane-associated CD14 and plasma levels of soluble CD14 in 10 patients (63 +/- 8 years of age), who underwent elective cardiopulmonary bypass.


RESULTS
Cardiopulmonary bypass induced marked postoperative monocytosis, which was maximal 20 hours after the operation (485 +/- 242 cells/microl before, 1080 +/- 264 cells/microl 20 hours after surgery). Expression of membrane-associated CD14 on classical CD14++ monocytes decreased significantly by 40%, reaching a nadir 20 hours after surgery (p < 0.05). At the time of maximal membrane-associated CD14 suppression, the levels of soluble CD14 measured by enzyme-linked immunosorbent assay were clearly increased (3.2 +/- 1.0 microg/ml before versus 5.6 +/- 1.0 microg/ml 20 hours after, p < 0.001). No significant change of the percentage of small (alpha) and large (beta) forms of soluble CD14 was found.


CONCLUSIONS
Cardiopulmonary bypass leads to reduced membrane-associated CD14 expression on peripheral blood monocytes and increased levels of soluble CD14 through shedding or secretion of membrane-associated CD14 from the cell surface. These findings indicate that bypass is associated with significant monocyte activation.
Fingerle-Rowson
G
G
Department of Internal Medicine I, Klinikum Grosshadern, University of Munich, München, Germany.
Auers
J
J
Kreuzer
E
E
Labeta
M
M
Schmidt
B
B
Samtleben
W
W
Ziegler-Heitbrock
H W
HW
Blumenstein
M
M
D015153:Blotting, Western; D002315:Cardiopulmonary Bypass; D001026:Coronary Artery Bypass / Q000379:methods*; D003327:Coronary Disease / Q000097:blood / Q000276:immunology / Q000601:surgery*; D015536:Down-Regulation / Q000502:physiology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007958:Leukocyte Count; D018950:Lipopolysaccharide Receptors / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D017452:Receptors, IgG / Q000378:metabolism
D018950:Lipopolysaccharide Receptors; D017452:Receptors, IgG