In the study of Bekris et al. (2018), CSF sTREM2 levels also correlated with a marker of blood–brain barrier disruption (CSF albumin–to–serum albumin ratio), raising the possibility that this latter may account for the relationship observed between peripheral and central sTREM2 concentrations in AD (Bekris et al., 2018). This evidence concerns the gene ALB and Alzheimer disease.