[Anti-aquaporin 4-antibody detection system]

To clarify the epidemiological and clinicopathological features of Japanese patients previously diagnosed as optic-spinal multiple sclerosis (OSMS)/neuromyelitis optica (NMO), we developed anti-AQP4 antibody assay and NMO-IgG immunohistochemistry and tested the presence of the antibody in a large population of patients. Almost 70% of OSMS/NMO with long spinal cord lesions were positive for this antibody. Antibody-positive patients were more likely to be female and blind, and had more relapses yearly and 68% of patients showed cerebral lesions on brain MRI and low frequency of oligoclonal bands in cerebrospinal fluid. The antibody titers related closely to the disease activity. The lesions involved were closely related to the areas of abundant AQP4 water channel expression. These evidence suggested the pathomechanical relations of the antibody to this disease.