AQP4 and neuromyelitis optica: Five NMO cases (NMO-2, 3, 4, 7 and 10) and one NMOSD case showed loss of Cx43 and AQP4 staining in degenerative GFAP-positive astrocytes in active lesions beyond the demyelinated areas as determined by myelin protein (MOG, MBP, and OSP) staining.