Impaired antioxidant defense mechanisms in two children with hemolytic-uremic syndrome

In the present study we have assayed antioxidant enzymatic activities of SOD, CAT, GSH-Px, GSH-Red, and G6PD in erythrocytes from two children with hemolytic-uremic syndrome (HUS) during the acute phase of the disease and after their recovery; in addition, we have tested the percentage of hemolysis after 24-h incubation in PBS containing glucose (1 g/1000 mL) or in the presence of their own plasma. Endogenous plasmatic MDA levels were also evaluated as lipid peroxidation marker. A significant decrease in SOD activity was found in erythrocytes from HUS patients, and the addition of their own plasma further decreased SOD activity. Elevated percentage of hemolysis was found in HUS patients when RBCs were incubated in their own plasma; this last effect was less evident in PBS + glucose.