Membrane studies on rod-shaped red cells in hereditary elliptocytosis: least haemolysis and normal sodium influx with decreased membrane lipids.

The clinical features of hereditary elliptocytosis were studied in 25 cases and compared with 20 normal individuals. Based on morphological features, these patients were classified into two groups: those with a rod-shaped type of elliptocytosis (nine cases), and those with a non-rod type (16 cases). Most of the cases with overt haemolysis were detected among cases of the non-rod type. Overt haemolysis typically tended to be accompanied by stomatocytic changes, which appear to be superimposed on elliptic transformation of the red cells. Sodium influx increased in eight of nine HE patients with overt haemolysis, but in none of the HE with rod-shaped red cells. Significant quantitative and qualitative differences in red cell membrane lipids were observed between the two types of HE. No spectrin abnormalities in domain composition, dimer-dimer association, and thermal stability were observed in 11 of the HE patients studied, including four cases with overt haemolysis.