Erythrocyte calcium abnormalities in sickle cell disease.

During a relatively brief tenure in the circulation, sickle erythrocytes may become dehydrated and irreversibly deformed and acquire extensive membrane damage. Abnormally high intracellular calcium concentrations may contribute to these abnormalities, as evidenced by the fact that many of them may be reproduced through ionophoric leading of normal red cells with small amounts of calcium. Sickle erythrocytes have another, possibly related, abnormality; they adhere to cultured vascular endothelium, perhaps due to the disordered (i.e., clumped) negative surface charge present on many Hb SS red cells. This endothelial adherence may have pathophysiologic significance, in that the attendant slowing of erythrocyte circulation may help initiate and propagate vascular occlusions.