Considering the sophisticated mechanisms used by the parasites to escape damage by ROS and the variety of mechanisms by which the host achieves ROS production, allied with the susceptibility of some species of Leishmania to ROS [52], it was reasonable to infer that ROS may play a role in resistance to L. amazonensis. Lesion development in gp91phox−/− and WT mice after infection with L. amazonensis was quite different. This evidence concerns the gene CYBB and infection.