In this study, applying established NMO/NMOSD criteria for idiopathic CNS demyelinating diseases, including anti-AQP4 antibody positivity, we observed higher levels of IL-17A, IL-6, CXCL8, G-CSF, CCL4 and CXCL10 in the CSF of patients with NMO/NMOSD in the relapse phase than in the CSF of OND patients. This evidence concerns the gene IL17A and neuromyelitis optica.