[Rheologic features of erythrocytes in beta-thalassemia minor]

The study assessed the physical characteristics of erythrocytes, viscosity and deformability, measured by a widely described double-filtration method. At the same plasma-cell viscosity was measured and the importance of the rigidity of RBC was evaluated as one of the many forces which interact among the cells and between the plasma and cells. The results showed a marked increase in corpuscular viscosity with reduced deformability, and a significant diminution of plasma-erythrocytic viscosity, whereas total viscosity remained unaltered. These parameters do not correlate with the quantitative pathological alterations of HbA2, but only with RDW-SD. Alterations of the proteic components with a relative increase in the alpha-chains of the erythrocytic membrane are thought to be responsible for these anomalies, by means af the modifications that the excess of alpha-globin causes to the structure and function of erythrocytic membrane; but the quantity of globin is not the decisive factor, and in fact the introduction of the beta-chains are able to correct erythrocytic deformability (Sorensen). Membrane rigidity is probably independent and unrelated to microcytemia, because these erythrocytes, have an excess of surface in relation to their volume, due to the simultaneous alteration of permeability. The diminished plasma-erythrocytic viscosity should be connected with the prevalence of repulsing forces, due to erythrocytic rigidity in relation to the attracting forces due to the proteic fractions which remain unchanged.