Erythrocyte adhesion in sickle cell disease.

The vaso-occlusive process in patients with sickle cell disease is complex and is likely to involve interactions between hemoglobin S red blood cells (SS RBCs) and vascular endothelium, as well as between SS RBCs and leukocytes. Vaso-occlusive events lead to recurrent pain and a wide spectrum of end-organ damage, including pulmonary hypertension and renal failure. However, the triggers inducing adhesion and vaso-occlusion are only now being elucidated. Investigators have characterized the ability of a number of RBC surface structures to adhere to both endothelial cells and components of the subendothelial extracellular matrix. In addition, evidence is accumulating to suggest that SS RBC adhesion receptors undergo activation under physiologic conditions. An understanding of these mechanisms at the molecular level should ultimately allow development of new preventive and treatment strategies to abrogate vaso-occlusive events.