APOE and Alzheimer disease: Bowman G.L. et al. has analyzed the relationships between biochemical markers of BBB integrity, clinical risk factors, CNS IgG synthesis, apolipoprotein E (APOE) genotype, MR-derived white matter hyperintensities (WMH), and volume changes via clinical assessments, brain imaging, CSF and plasma collection, and assessing the CSF–albumin index (CSF-AI) for determining BBB integrity over one year in patients with mild to moderate AD to discover the BBB stability and its functional importance [318].