KLK8 and Alzheimer disease: To examine whether CSF KLK6, KLK8 or KLK10 concentrations are associated with the CSF biomarkers for AD (CSF-Aβ42, CSF-tTau, CSF-pTau), linear regression analyses with the dependent variable CSF-Aβ42 (or CSF-tTau or CSF-pTau, respectively) and the independent variable KLK6, KLK8 or KLK10, were performed separately in the patient sample and in NC.