α-Thalassemia does not seem to influence erythrocyte deformability in sickle cell trait carriers

Studies dealing with rheological red blood cell (RBC) behavior in sickle cell trait carriers are scarce. Moreover, the association with α-thalassemia (α-thal), which also modifies erythrocyte behavior, has not always been taken into account. We analyzed erythrocyte deformability by means of a shear stress diffractometer, along with hematological and biochemical parameters (glucose and plasma lipids), given their possible influence on erythrocyte deformability, in 14 sickle cell trait carriers and 23 healthy controls. Nine patients were also α-thal carriers and five were not. Among the thalassemia carriers, eight were heterozygous and one was homozygous. When compared with controls, sickle cell trait carriers showed no differences for any of the biochemical parameters analyzed (p > 0.05), but significantly lower hemoglobin (Hb) (p = 0.003), mean corpuscular volume (MCV) and mean corpuscular Hb (MCH) (p < 0.001) levels, although no differences in erythrocyte deformability were observed at any of the shear stresses tested (p > 0.05). When comparing sickle cell trait carriers, with and without α-thal, no differences in erythrocyte deformability were observed (p > 0.05), in spite of the former showing lower MCV and MCH (p < 0.05) levels. Carriers of α-thal had lower Hb S [β6(A3)Glu → Val; HBB: c.20A > T] levels (p = 0.013) than non carriers. The existence of a compensating mechanism seems reasonable because, despite presenting lower erythrocyte indices, which could worsen erythrocyte deformability, this rheological property improves when the percentage of Hb S is lower.