Quantification and Functional Characterization of Antibodies to Native Aquaporin 4 in Neuromyelitis Optica Sudhakar Reddy Kalluri, MSc; Zsolt Illes, MD; Rajneesh Srivastava, MSc; Bruce Cree, MD; Til Menge, MD; Jeffrey L. Bennett, MD, PhD; Achim Berthele, MD; Bernhard Hemmer, MD Arch Neurol.
Autoantibodies against astrocyte water channel aquaporin-4 (AQP4) are highly specific for the neuroinflammatory disease neuromyelitis optica (NMO). We measured the binding of NMO autoantibodies to AQP4 in human astrocyte-derived U87MG cells expressing M1 and/or M23 AQP4, or M23 mutants that do not form orthogonal array of particles (OAPs).
The aquaporin-4 (AQP4) water channel antibody is used in the diagnosis of neuromyelitis optica (NMO) due to its high sensitivity and high specificity. However, some patients are reported to have neither optic neuritis nor myelitis despite being positive for the AQP4-autoantibody (AQP4-Ab). Therefore, recent reports suggest that such patients should be diagnosed as having ‘AQP4-autoimmune syndrome’.
We identified the autoantibody against phosphoglycerate mutase 1 (PGAM1), which is a glycolytic enzyme, in sera from multiple sclerosis (MS) patients by proteomics-based analysis. We further searched this autoantibody in sera from patients with other neurological diseases. The prevalence of the anti-PGAM1 antibody is much higher in patients with MS and neuromyelitis optica (NMO) than in those with other neurological diseases and in healthy controls.
Neuromyelitis optica (NMO) is an inflammatory demyelinating disease of the central nervous system (CNS). Anti-aquaporin-4 antibody (AQP4-Ab) is a highly specific serum autoantibody that is detected in patients with NMO. Several lines of evidence indicate that AQP4-Ab not only serves as a disease marker but also plays a pivotal role in the pathogenesis of NMO