AQP4 and neuromyelitis optica: In order to determine whether poor response to IFN-β is related to the crucial LSCL or the NMO disease entity itself, we evaluated spinal cord involvement in Taiwanese patients with MS and NMO and correlated their MRI and anti-aquaporin-4 auto-antibodies (AQP4 Ab) with their response to IFN-β in the special clinic for MS at Taipei Veterans General Hospital (VGH) from 2002–2008.