NMO-IgG is a specific biomarker of neuromyelitis optica (NMO) that targets the aquaporin-4 (AQP4) water channel protein. The current gold standard for NMO-IgG identification is indirect immunofluorescence (IIF).
The detection of aquaporin-4 (AQP4) antibodies in neuromyelitis optica (NMO) led to a breakthrough in diagnosing NMO. To date, different assays to detect these antibodies are available.