Abstract Objective The purpose of this study was to examine the levels of cerebrospinal fluid (CSF) apolipoprotein E (apoE) species in Alzheimer’s disease (AD) patients. Methods We analyzed two CSF cohorts of AD and control individuals expressing different APOE genotypes. Moreover, CSF samples from the TgF344-AD rat model were included. Samples were run in native- and SDS-PAGE under reducing or non-reducing conditions (with or without β-mercaptoethanol). Immunoprecipitation combined with mass spectrometry or western blotting analyses...