IL6 and primary progressive multiple sclerosis: Excluding cases who had received therapy, levels of IL-6 and CXCL8 were higher in NMO/NMOSD patients than in MS, PPMS and OND patients (IL-6: p = 0.016, 0.014, and 0.000044; CXCL8: p = 0.024, 0.027, and 0.0007, respectively), and levels of IL-17A and G-CSF were significantly higher in NMO/NMOSD patients compared with OND patients at relapse (p = 0.012 and 0.0079, respectively).