Morphology and physiology of the McLeod erythrocyte. I. Scanning electron microscopy and electrolyte and water transport properties.

The McLeod phenotype is a rare condition characterized by deficiencies in the Kell blood group antigens of erythrocytes. The present study has defined some of the morphological and physiological characteristics of these red cells. Scanning electron microscopy reveals that approximately 27% of McLeod cells are morphologically abnormal. These aberrant forms resemble the acanthocytes of abetalipoproteinemia. Incubation experiments indicate that the morphology of McLeod erythrocytes is not due to a plasma factor. Biochemical studies reveal that the lipid composition and microviscosity of these erythrocytes are normal. In addition, isotopic tracer experiments indicate that electrolyte transport is also within the normal range. However, osmotic water permeability is approximately 30% below normal. The absence of a lipid abnormality and other experimental data suggest that the abnormal morphology and reduced H2O permeability of the McLeod erythrocyte may be due to defective membrane protein.