Glial fibrillary acidic protein as a biomarker in neuromyelitis optica spectrum disorder: a current review.

In patients with AQP4-IgG NMOSD, GFAP levels are elevated in CSF and serum during acute attacks and correlate with disability, consistent with the pathophysiology of this antibody-mediated astrocytopathy. Serum GFAP levels tend to be higher in AQP4-IgG NMOSD than in its differential diagnoses, multiple sclerosis, and myelin oligodendrocyte antibody-associated disease. Importantly, serum GFAP levels in AQP4-IgG NMOSD during remission may be predictive of future disease activity. Serial serum GFAP measurements are emerging as a biomarker to monitor disease activity in AQP4-IgG NMOSD and could have the potential for application in clinical practice.