CAT and B-cell chronic lymphocytic leukemia: To further confirm the role of H2O2 in AA-mediated cytotoxicity, CLL B-cells were pre-incubated with the iron chelator deferoxamine (DFX) (which inhibits H2O2 generation [37]) at a concentration of 100 μM for 3 h and then treated with 250 μM AA or co-treated with AA and the H2O2 scavengers catalase or sodium pyruvate (SP).