Blood polymorphonuclear leukocytes from the majority of sickle cell patients in the crisis phase of the disease show enhanced adhesion to vascular endothelium and increased expression of CD64.

There is increasing interest in the role of blood polymorphonuclear leukocytes (PMNs) in the pathogenesis of sickle cell crisis. We studied the adherence of PMNs from 18 sickle cell patients in crisis, 25 out of crisis, and 43 healthy subjects (controls) to monolayers of human umbilical cord endothelium that were either untreated or pretreated with tumor necrosis factor alpha (TNFalpha). Overall, the PMNs from patients in crisis were more adherent than control PMNs to untreated endothelial monolayers (mean 53% increase; P < .

Effects of cell purification methods on CD11b and L-selectin expression as well as the adherence and activation of leucocytes.

This study investigated the effects of commonly used procedures for the isolation of leucocytes from human blood in comparison with cells in whole blood on the surface expression of CD11b and L-selectin (adhesion molecules which are known to be increased and decreased respectively by cell activation). Washing of granulocytes or monocytes with Hanks' buffered salt solution after separation by either dextran sedimentation or density gradient centrifugation, increased surface expression of CD11b (p < 0.05).

Red blood cells from patients with sickle cell disease exhibit an increased adherence to cultured endothelium pretreated with tumour necrosis factor (TNF).

Red blood cells (RBCs) from 24 patients with sickle cell disease were more adherent to cultured endothelium pretreated with the inflammatory cytokine, tumour necrosis factor (TNF) than RBCs from 22 healthy subjects. The enhanced sticking was apparent in RBC preparations from patients who were in crisis (mean 190% increase from controls) and out of crisis (mean 220% increase) and was not related to the number of circulating RBCs, reticulocytes, platelets, leucocytes or haemoglobin levels. When irreversibly sickled RBCs, enriched by centrifugation on density gradients, were added to TNF-treated endothelium they were found to be significantly more adherent (mean 411% increase; P < 0.