GSTM1 and Schnyder corneal dystrophy: 7, 8 H2O2 produced by the pneumococcus oxidizes oxy-hemoglobin (Fe2+) from different mammals, including humans, to produce the non-oxygen-binding form of hemoglobin known as met-hemoglobin (Hb-Fe3+).9, 10 The oxidation of hemoglobin by Spn produced toxic species, including labile heme11 and a hemoglobin-derived tyrosyl radical [Fig. 1A, (•Hb-Fe4+)].12 These toxic products are implicated in the pathophysiology of human diseases characterized by intravascular hemolysis, such as sickle cell disease (SCD), and in inflammatory conditions, such as sepsis.13, 14, 15