Heterogeneity of red cells in the sickler: a characteristic with practical clinical and pathophysiological implications.

The role of heterogeneity of red cells and its relation to the severity of sickle cell anemia has been examined by the use of spontaneously formed continuous density gradients. We have found that sicklers have a more heterogeneous distribution of cell densities than normals; that this heterogeneity varies greatly from patient to patient; and that this heterogeneity is functionally significant because it involves changes in MCHC and O2 affinity. Extrapolation of HbS solution data to clinical situations will have to account for heterogeneity, and previous efforts to correlate ISC's with severity might have ignored the role of cells with high density but without the classical morphological features associated with these types of cells.