PPBP and Alzheimer disease: Some of the other AMPs were already linked to AD; S100A7 is a recently discovered potential biomarker for AD (Qin et al., 2009; Fleming et al., 2012), and PPBP and AZGP1 were shown to be downregulated in the serum of patients with AD (Shen et al., 2017); our study confirms their downregulation in CSF.