PDCD6IP and Alzheimer disease: However, in 2006, Rajendran et al. described the presence of the Aβ protein (a toxic protein accumulated in brain parenchyma typical for Alzheimer’s disease (AD) in exosomes released by human embryonal carcinoma cell line NT2a, as well as the presence of an exosome-associated Alix protein in the amyloid plaque of three AD patients [102].