F-cells are preferentially distributed among high density erythrocytes

Red blood cells from normal subjects and subjects with heterocellular hereditary persistence of fatal haemoglobin and beta-thalassaemia were fractionated according to density by centrifugation on a discontinuous gradient of Stractan II. F-cells were studied by immunofluorescence and their proportion was evaluated in each separated population. This approach has permitted to show that F-cells were preferentially distributed among high density erythrocytes. This phenomenon reflects a peculiar characteristic of F-cells.