This study focusing on morphological features of neuromyelitis optica (NMO) in autopsied central nervous system (CNS) astrocytes demonstrated that NMO is a global astrocytopathy characterized by a wide range of morphologies, including sublytic reactions, other signs of degeneration and emperipolesis. Astrocyte reactivity in NMO may not involve direct IgG binding to a cell and is also observed in non-lesional areas of astrocytes that retain aquaporin-4 (AQP4) protein.
Why this matters
NMO can be distinguished from other CNS demyelinating diseases by detecting the expression of AQP4, which is expressed predominantly in astrocytes.
Classical astrocytic reactions such as astrogliosis are nonspecific and generally studied in the CNS diseases which do not selectively target astrocytes.
Astrocytic response in a cell-specific attack can be potentially identified in NMO, since the primary driver of NMO neuropathology is AQP4-specific IgG.