Alterations of the Neuroinflammatory Markers IL-6 and TRAIL in Alzheimer's Disease

Objective: We aimed to identify biomarkers of Alzheimer's disease (AD) in order to improve diagnostic accuracy at mild stage. Methods: AD patients aged >50 years were included in the disease group. We evaluated the relationship between potential blood and cerebrospinal fluid inflammatory biomarkers, cognitive status, temporal lobe atrophy and disease severity. Inflammatory biomarkers including interleukin 6 (IL-6), IL-18, fractalkine and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) levels were measured. APOE genotypes were determined. Results: We enrolled 41 subjects in the disease group and 40 subjects in the normal control group. The majority (88.9%) of subjects in the disease group had mild AD. Elevated levels of plasma IL-6 and decreased levels of plasma TRAIL in the disease group were noted. Plasma levels of IL-6 and TRAIL were significantly correlated with their cerebrospinal fluid levels. Conclusion: Plasma IL-6 and TRAIL were identified as potential biomarkers of AD at an early stage.