NOS2 and myeloid sarcoma: These results are in agreement with several recent studies reporting up-regulation of iNOS (Calabrese et al. 2002; Kahl et al. 2003) and elevation of serum and CSF levels of its metabolites NO3 and NO2 in MS patients (Cross et al. 2006; Giovannoni et al. 1997; Johnson et al. 1995; Nazliel et al. 2002; Stepień et al. 2013).