In vascular pathological conditions, such as atherosclerosis with intraplaque hemorrhage [10], subarachnoid hemorrhage [11], sickle cell disease [12] and sepsis [13], Hb is liberated from RBCs and accumulates as cell-free Hb in tissues out of control from the cellular antioxidant defense system. This evidence concerns the gene GSTM1 and sickle cell disease.