Moving boundary electrophoresis and sialic acid content of normal and polycythaemic red blood cells.

Moving boundary electrophoresis has been used for the assessment of the negative charge on erythrocyte membranes. The equipment is easy to construct and simpler to use than the microelectrophoresis technique. There is a direct relationship between the electrophoretic velocity measured by the moving boundary method and the sialic acid content of the red cell membrane. Polycythaemic erythrocytes have a higher electrophoretic mobility and higher sialic acid content than normals. Separation of the erythrocytes according to their densities shows that old polycythaemic erythrocytes have a higher electrophoretic mobility and sialic acid content than young normal ones. This suggests that the difference is not associated with a younger erythrocyte population in polycythaemia vera, but may represent a membrane change in the abnormal erythroid clone present in this disease.