Lactoferrin in cerebrospinal fluid and saliva is not a diagnostic biomarker for Alzheimer's disease in a mixed memory clinic population

Background: The pathological changes in Alzheimer's Disease (AD) and other neurodegenerative disorders begin decades prior to their clinical expression. However, the clinical diagnosis of neurodegenerative dementias is not straightforward. Lactoferrin is an iron-binding, antimicrobial glycoprotein with a plethora of functions, including acting as an important immune modulator and by having a bacteriocidic effect. Two previous studies indicated that salivary lactoferrin could differentiate between neurodegenerative dementias. Methods: A total of 222 cerebrospinal fluid (CSF) and saliva samples from a consecutive, mixed memory clinic population were analysed for lactoferrin. In addition, the association between lactoferrin in CSF and saliva and the concentration of tau, phosphorylated tau (p-tau) and amyloid 1–42 (Aβ42) in CSF were addressed. Findings: CSF lactoferrin was assessed for the first time in a cohort of patients with neurodegenerative dementias. No significant differences were found in the levels of CSF or saliva lactoferrin between the diagnostic groups. In addition, no significant relationships were found between lactoferrin levels and tau, p-tau and Aβ42, respectively. Interpretation: Neither CSF nor saliva lactoferrin could differentiate between neurodegenerative dementias in this study.