Moreover, combined activity of arginase 1 and iNOS enzymes has been shown to be important in the suppressive activity of mouse MDSCs in tumors (Bronte et al., 2003), but there are also several evidences of the role of MDSCs, iNOS, and L-arginine depletion in infectious diseases as chronic infections with helminthes (Brys et al., 2005). The gene discussed is NOS2; the disease is infectious disease.