Isolation and quantitation of human erythrocyte deformability classes.

A new technique is described that fractionates erythrocytes according to their deformability. The method is a modification of the method of Beutler et al. (J Lab Clin Med 1976;88:328-33), in which small cellulose columns are used to remove white cells from blood samples. We find that when the length-to-width ratio of the columns is increased, the mixed cellulose bed also fractionates the red cells. Measurement of mean cell volume, mean corpuscular hemoglobin concentration, hemoglobin level, deformability index, and cell density showed that deformability is the physical property of the erythrocyte that forms the basis for the fractionation. This is a separation modality that complements the numerous density gradient techniques for red cells. The following experimental results can be obtained by using the technique: (1) The number of cells with a defined degree of rigidity can be quantitated in an erythrocyte population. (2) Large numbers of cells that differ with respect to their deformability can be isolated. (3) Application of the method to sickle cells has quantitated the remarkable heterogeneity of these cells with regard to their deformability.