To evaluate the effects of NMO-IgG on AQP4 expression in ependymal cells, primary cultures were treated for 24 hours with NMO-IgG purified from seven different NMO patients (called NMO1-IgG to NMO7-IgG) and compared with NT or CTRL-IgG (a purified pool from healthy donors) conditions. The gene discussed is AQP4; the disease is neuromyelitis optica.