APOE and Alzheimer disease: After virus injection, plasma human ApoE was detected and rapidly reached the maximum level at 4–6 days in the AD-ApoE Kyoto and AD-ApoE Sendai groups (17.4 ± 3.1 μg/mL vs.: 22.2 ± 4.5 μg/mL, respectively) and at 2 days in the AD-ApoE3 group (38.4 μg/mL).