In humans, although NO production by monocyte-derived Mφs remains controversial, both iNOS and NO are detected in granulomas and alleles for NOS2 are associated to TB susceptibility (Nicholson et al., 1996; Facchetti et al., 1999; Choi et al., 2002; Schon et al., 2004; Moller et al., 2009). The gene discussed is NOS2; the disease is tuberculosis.