['We studied erythrocyte (RBC) caspase-3 activity and oxidative status in plasma and RBCs of 33 patients with type 2 diabetes at first clinical onset and 23 age-matched non-diabetes control subjects.', 'Caspase-3 activity was assayed during the life span of RBCs; lipid peroxides and total antioxidant capacity (TEAC) were assessed in plasma and RBCs as indicators of oxidative stress and non-enzymatic antioxidant defense; and superoxide dismutase, catalase, and glutathione peroxidase activity were measured in RBCs as enzymatic antioxidants.', 'We found that, compared to controls, RBCs caspase-3 is activated early in type 2 diabetes (P < 0.05); TEAC and malondialdehyde increased in plasma of patients with early diabetes, even when hypertension and macroangiopathy were present (P < 0.01); and RBCs TEAC, malondialdehyde (P < 0.01), superoxide dismutase, and glutathione peroxidase (P < 0.05) exhibited similar behavior in patients with diabetes and hypertensive patients with diabetes.'] Is erythrocyte caspase-3 and antioxidant defense activated in red blood cells and plasma of type 2 diabetes patients at first clinical onset?