Generation of superoxide anion and hydrogen peroxide by erythrocytes from individuals with sickle trait or normal haemoglobin

. To test the hypothesis that the resistance of sickle trait (AS Hgb) erythrocytes (rbcs) to malaria may be mediated by increased production of activated oxygen species, the production of superoxide anion (O 2 –) and hydrogen peroxide (H 2 O 2 ) by AS rbcs and normal (AA Hgb) rbcs was measured under defined conditions. Formation of O 2 – and H 2 O 2 was time, temperature and oxygen saturation dependent. Reproducible measurement of O 2 – formation required the presence of 0·2 mmol l ‐1 KCN to inhibit a cytochrome oxidase activity found in the cytochrome C preparation used. There was an inverse relationship between cell concentration and O 2 – and H 2 O 2 formation. Use of the inhibitor of superoxide dismutase (SOD), diethyldithiocarbamic acid, increased the amount of O 2 – measured. When rbcs from blacks with AS Hgb and with AA Hgb were incubated under standardized conditions, significantly ( P < 0·05) more O 2 – was formed by AS than AA cells (24·3 v. 14·5 mmol per mol Hgb). These findings show that AS rbcs can generate more O 2 – than AA rbcs. The increased formation of O 2 – by rbcs containing AS Hgb may contribute to the resistance of AS rbcs to malarial parasitism.