Sera from NMO patients contain non-reactive AQP4 antibodies, identified as recombinant antibodies (rAb) ON-12-2-46 and ON-07-5-31 which target glucose-regulated protein 78 (GRP78) on the cell surface of brain microvascular endothelial cells (BMEC). The gene discussed is AQP4; the disease is neuromyelitis optica.