Does soluble intercellular adhesion molecule-1 (ICAM-1) affect neutrophil activation and adhesion following ischaemia-reperfusion?

Objectives: to examine the effect of reperfusion plasma and sICAM-1 on neut rophil integrin expression and neutrophil adhesion to determine if sICAM-1 has a potential role in the regulation of neutrophil adhesion. Materials: twenty-seven patients, 17 men and 10 women undergoing femorodist al surgery. Blood was taken preoperatively and from the femoral vein follow ing the release of the cross-clamp Neutrophils were obtained from Jive volu nteers and incubated with phosphate buffered saline (PBS), preoperative pla sma or reperfusion plasma with and without sICAM-1. Neutrophil expression o f CD11b and adhesion were measured. Main results: neutrophil CD11b expression did nor change following incubati on in the three media. Neutrophil adhesion increased significantly followin g exposure to reperfusion plasma compared to PBS or preoperative plasma (45 .5 adhesion vs. 12.75%, p<0.01 Mann-Whitney U-test). Soluble ICAM-1 decreas ed CD11b expression and adhesion in neutrophils exposed to reperfusion plas ma only (CD11b expression fell from 15.9 to 3.4 mcf, p<0.01 Mann-Whitney U- test and adhesion fell to 11.6% cells adhered, p<0.01). Conclusion: an increase in CD11b expression is not required for an increase in neutrophil adhesion. The change in neutrophil adhesion produced by repe rfusion plasma can be blacked by sICAM-1. Soluble ICAM-1 may have a physiol ogical role in the regulation of neutrophil adhesion.