α4/β1-integrin expression on sickle reticulocytes: Vascular Cell adhesion molecule-1-dependent binding to endothelium

Abstract

Important complications in sickle cell anemia occur secondary to vascular occlusion, which is postulated to be initiated by interactions of erythrocytes with vascular endothelial cells. In patients with sickle cell anemia, up to 25% of reticulocytes express the α4β1-integrin complex. Furthermore, erythrocytes from patients with sickle cell anemia bind to endothelial cells activated by tumor necrosis factor α via (TNFα) via interactions between erythrocyte α4β1 and endothelial cell vascular cell adhesion molecule-1 (VCAM-1). Thus, binding of α4β1-expressing reticulocytes to cytokine-activated endothelial cells may initiate vascular complications in sickle cell anemia and perhaps other hemolytic anemias during episodes of infection and inflammation. © 1993 by The American Society of Hematology.