Increased GFAp levels in CSF as a marker of organicity in patients with Alzheimer's disease and other types of irreversible chronic organic brain syndrome.

Glial fibrillary acidic protein (GFAp), an astrocyte-specific protein, was determined in cerebrospinal fluid (CSF) of adults and children with global cognitive dysfunction. In children CSF-GFAp values were not closely associated with organic brain disease. However, GFAp values in CSF were increased in 65 of 121 samples of adults with dementia, independent of its cause. GFAp values were not correlated with the severity of the dementia. Increased levels in the CSF are believed to indicate reactive gliosis in most patients with dementia, whereas GFAp levels in encephalitic patients normalize after clinical recovery.