IL6 and neuromyelitis optica: A significant level of IL-6 was found in the serum sample of NMO patients compared to that in OND patients (p = 0.003), while the IL-6 CSF/Serum ratio was significantly higher in NMO patients (mean ± SD, 1255.1 ± 2596.4) compared to that in OND patients (mean ± SD, 12.3 ± 8.7) (p < 0.001), indicating that IL-6 has major role in pathogenesis of NMO [83].