[Mechanisms for the enhanced red cell destruction in hemoglobinopathy]

The process of denaturation of Hb within red cells, leading to ultimate formation of Heinz body or aggregates of irreversibly denatured Hb, was formulated over 20 years ago. The mechanical obstruction due to Heinz bodies seems self-evident as a cause of enhanced red cell destruction. Recent studies compare the overall defects in rheologic properties of red cells of unstable Hb disorder with artificially oxidized red cells. The fate of superoxide anion which is the other product of oxidative denaturation of Hb is being discussed in the light of accumulation of oxidative damage to red cell membrane. From this aspect, unstable Hb disorder may be regarded as a model of accelerated red cell aging. The aged red cells appear to bind increased amounts of immunoglobulin. They may express scavenger ligands. The rheologic defects and altered surface phenomena would be additive in enhancing red cell phagocytosis. The chemical basis for the abnormal properties of unstable Hb red cells, as well as normal senescent red cells, is yet to be defined.