 Activated PKR was specifically found in the cytoplasm and nucleus, as well as co-localized with neuronal apoptotic markers.Further studies have assessed the levels of PKR in blood and cerebrospinal fluid (CSF) of AD patients and controls.The result of an analysis of the concentrations of total and phosphorylated PKR (pPKR) in peripheral blood mononuclear cells (PBMCs) in 23 AD patients and 19 control individuals showed statistically significant increased levels of the ratio of phosphorylated PKR/PKR in AD patients compared with controls.