IM enhanced the effect of antioxidants in prevention of IM resistance. B/A-early cells were cultured for 8 weeks in medium supplemented with IL-3 (B/A) and PDTC, NAC, VE, and IM administered individually or in combinations of an antioxidant with IM. ROS levels were examined by fluorescence (Relative fluorescence). Cells were plated in methylcellulose in the presence or absence of 2 μM IM and absence of growth factors, and colonies were counted after 7 days. Results represent percent of IM-resistant cells (mean ± SD); P < .05 compared with other groups (^*), B/A + IM group (^**), and corresponding group treated with antioxidant only (^***).