Release of spectrin-free spicules on reoxygenation of sickled erythrocytes

It has long been suspected that the erythrocytes of patients with sickle cell disease gradually shed part of their plasma membrane either through a normal ageing process or as a result of repeated sickling, and that this membrane loss may be associated with the formation of irreversibly sickled cells1–3. We report here that when sickled HbS erythrocytes are unsickled by reoxygenation, the cells lose ∼2–3% of their lipid as spectrin-free haeomoglobin-containing spicules in the form of rods and microspheres. The rods, which still contain polymerized haemoglobin, eventually degrade to chains of microvesicles having diameters of ∼0.1 µm. Similar spicular material has been found in the untreated blood of patients with sickle cell disease.