Cation Content and Membrane Deformability of Heterozygous P-Thalassaemic Red Blood Cells

S ummary . The red blood cells of patients heterozygous for 8-thalassaemia contain less sodium, potassium and water than do normal red cells. Incubation of red cells in plasma at 37°C for 24 hr in the absence of glucose produced the following changes: (1) An increase in the red-cell sodium content of both normal and thalas-saemic cells. (2) A decrease in the red cell potassium content which was much more pronounced in thalassaemic than in normal cells. (3) A reduction in the total cation content of the red cells from patients heterozygous for β-thalassaemia; this reduction seemed to be related to the clinical severity of the disease, as well as the reduction in mean corpuscular volume and osmotic fragility. (4) The trapped plasma values, which reflect the deformability of red cells, were initially greater for thalassaemic red cells than normal cells and in both groups increased after incubation.
The addition of glucose to the incubation medium largely prevented the changes produced by incubation. The changes induced by incubation in vitro may be relevant to changes in vivo , where a local lack of glucose might lead to a loss of potassium and water from thalassaemic cells. This could give rise to shrinking of the red cells and a reduction in their deformability which may play a role in the haemolysis of heterozygous β-thalassaemia.