Impaired deformability of Heinz body-forming red cells

Although a decrease in the deformability of red blood cells (RBCs) has been suspected in Heinz body-forming hemolytic anemia, it remains uncertain whether the formation of Heinz bodies themselves impairs RBC deformability or not. To elucidate this question, we used RBCs treated with phenylhydrazine and RBCs from patients with unstable hemoglobin (Hb) disease (Hb Yokohama) to investigate the effect of Heinz body formation on deformability in terms of RBC filterability through nickel mesh and viscosity of the RBC suspension. The phenylhydrazine-treated RBCs exhibited a marked decrease in deformability in a dose-dependent manner. The Heinz body-forming RBCs from the patients also showed a marked decrease in deformability. Thus we confirmed that Heinz body formation impairs RBC deformability. Further, both phenylhydrazine-treated RBCs and RBCs from the patient showed a degradation of spectrin without any cross-linking of membrane proteins, thereby suggesting that the impaired deformability is associated with the oxidative degradation of the cytoskeletal framework. In summary, this study supports the conclusion that RBC deformability is impaired by the presence of Heinz bodies as well as the related oxidative damage involved in their formation.