Mechanism of red blood cell acanthocytosis and echinocytosisin vivo

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Abstract
Summary Patients with abetalipoproteinemia have an inborn absence of the major apoprotein of low density plasma lipoproteins, an abnormal serum and red cell lipid profile, and spiny erythrocytes, called acanthocytes. We now show that these deformed cells are reversibly converted to a normal shape, that of a biconcave disk, by incubation with 3 to 10×10−5 m chlorpromazine. We suppose that chlorpromazine acts by expanding the cytoplasmic leaflet of the bilayer, thus promoting inward curvature. Ghosts isolated from the acanthocytes are themselves spiny but are also converted to normal, convave disks by chlorpromazine or merely by a brief incubation at 37°C in low inoic strength buffer. We attribute the latter to a redistribution of lipids between the two leaflets of the membrane bilayer. Similar observations were made with red cells and ghosts from apatient with benign echinocytosis. These observations suggest that the morphological abnormality in acanthocytes and echinocytes can be ascribed to the same mechanism as crenationin vitro; that is, a bilayer couple effect in which an excess of surface area in the outer leaflet over the inner leaflet of the membrane bilayer drives outward curvature. It is striking that cells which were chronicallyabnormal in shapein vivo contain the information to become biconcave disks immediately upon simple chemical treatmentin vitro.