L-selectin expression increases on peripheral blood polymorphonuclear leukocytes during active marrow release

The cell adhesion molecule L-selectin is highly expressed on mature bone marrow polymorphonuclear leukocytes (PMN), and the release of these cells from the bone marrow could produce a population of circulating PMN expressing high levels of L-selectin. Because L-selectin initiates the interaction of PMN with activated endothelium, these cells could be important in the pathogenesis of multiorgan failure following sepsis and septic shock. The present study was designed to test the hypothesis that the release of PMN from the bone marrow increases the expression of L-selectin on circulating PMN. Peripheral blood and bone marrow samples were obtained immediately after sternotomy (BM1) and during (BM2) and just before closing the sternum (BM3) in five normothermic and five hypothermic cardiopulmonary bypass (CPB) procedures. L-selectin was measured using both immunocytochemistry and flow cytometry. The results showed that L-selectin expression on bone marrow PMN was greater than on peripheral blood PMN (p < 0.01...