Red cell deformability, splenic function and anaemia in thalassaemia

Red cell deformability (RCD) was measured in 38 patients with α‐thalassaemia and 48 patients with β‐thalassaemia, of whom 13 had undergone splenectomy. All splenectomized patients, but none of those with intact spleens, had very rigid erythrocytes with an elongation index <0.45 at a high shear stress of 30 Pa suggesting a splenic recognition threshold for removal of rigid red cells. At this shear stress RCD correlated strongly with the degree of anaemia in both the splenectomized ( r = 0.81, P < 0.001) and non‐splenectomized β‐thalassaemic patients (all patients r = 0.81, P < 0.001; homozygous β‐thalassaemic patients r = 0.51, P = 0.01). These data suggest that reduced RCD is a major determinant of anaemia in thalassaemia.