Antibodies to Aquaporin-4 (AQP4)
Aquaporin-4 antibodies are IgG class autoantibodies directed against the aquaporin-4 protein located on the surface of cells of the central nervous system.
Aquaporin-4 is primarily found in the optic nerves and spinal cord and plays an important role in regulating water balance within brain and spinal cord tissues. When these antibodies are produced, the immune system damages cells containing this protein, leading to inflammation and disruption of nerve signal transmission.
These antibodies are a specific marker of Neuromyelitis Optica (NMO, Devic's disease), a severe autoimmune disorder affecting the optic nerves and spinal cord.
The test plays a key role in the early diagnosis and differential diagnosis of demyelinating diseases of the nervous system.