Lactoferrin of oral fluid is normal and in Alzheimer's disease: laboratory and diagnostic aspects (review of literature).

The article discusses the clinical value of determining the lactoferrin protein in oral fluid - one of the representatives of the saliva proteome. The review is based on the analysis of modern literature, including systematic reviews, the results of multicenter prospective studies, review and original articles by leading experts in this field, presented in the databases PubMed, Scopus, CyberLeninka. The problems of the preanalytical stage, methods for determining lactoferrin are highlighted and information about its content in mixed saliva according to various authors is provided. Special attention is paid to the clinical and diagnostic value of the level of salivary lactoferrin in Alzheimer's disease. According to most authors, the diagnostic sensitivity of this parameter ranges from 87 to 100%. Some mechanisms of the relationship between this protein and the central nervous system (CNS) are shown. In conclusion, it is concluded that salivary lactoferrin can be an "indicator" of the formation of amyloid plaques and can be considered as one of the reliable biomarkers of Alzheimer's disease. This opinion is based both on fundamental ideas about the global relationship between innate immunity and the central nervous system, and on clinical data. The special advantage of this laboratory test is its non-invasiveness, which makes it more preferable in comparison with the determination of amyloid and tau proteins in the cerebrospinal fluid and blood.