Further evidence for oxidative damage to hemoglobin and red cell membrane in leukemia

The presence of significant methemoglobinemia in a large number (79%) of cases of leukemia prompted us to look into the evidence for oxidative injury to the other red cell constituents, e.g. the cell membrane. Forty-five per cent of cases showed increased malonyldialdehyde (MDA) levels indicating in vivo peroxidation of membrane lipids in leukemia patients. Red cell superoxide dismutase (SOD) activity was reduced in 25% of cases while plasma α-tocopherol levels were markedly low in 68% of patients. The presence of an inverse correlation between MDA levels and SOD and tocopherol levels in a large number of cases suggested that the red cells in leukemia lack the ability to counter increased oxidative stress. Low hemoglobin content of the red cells in these patients seemed to contribute to the oxidative injury to the membrane by rendering the latter more accessible to the oxidants. While methemoglobinemia may enhance tissue hypoxia, membrane lipid peroxidation could explain the shortened erythrocyte life-span and anemia in leukemia.