Here, we found for the first time that serum levels of autologous Hsp90 were significantly elevated (2.79-fold increase; p < 0.0001) in AD patients when compared to age- and gender-matched healthy controls (mean ± SD; 215.41 ± 146.14 pg/ml vs. 84.64 ± 79.96 pg/ml), as measured quantitatively by a commercially available ELISA kit (Fig. 1). Here, HSP90AA1 is linked to Alzheimer disease.