APOE and dementia: To begin to characterize changes in plasma protein levels due to variation of APOE3 or APOE4 alleles, we measured 1305 proteins in blood plasma from 36 APOE3/3 and 17 APOE4/4 elderly subjects (mean age = 68 years) (Fig. 1A,B), all of whom were without dementia, as assessed by both CDR and MMSE scores (Fig. 1B).