Evaluation of serum NFL, T-tau, p-tau181, p-tau217, Aβ40 and Aβ42 for the diagnosis of neurodegenerative diseases

Abstract Objectives To assess the variations and diagnostic performance of serum biomarkers of neurodegenerative diseases. Methods In this monocentric prospective study, neurofilament light (NFL), T-tau, p-tau181, p-tau217, Aβ40, and Aβ42 were measured in serum collected from orthopedic patients (control group, n=114) and patients in the neurology department (n=69) previously diagnosed with Alzheimer’s disease (AD, n=52), parkinsonian syndromes (n=10), and other etiologies of neurodegeneration (non-AD, n=7). Results In the control group, serum NFL, T-tau, p-tau181, p-tau217, and Aβ40 significantly increased with age, independently of sex. NFL (p=0.0078), p-tau217 (p<0.001) were significantly increased with neurodegeneration when compared to controls, with only p-tau217 significant in the multivariate analysis (p<0.001). Multivariate regression analysis accounting for age highlighted a significant increase of p-tau217 (p<0.001) in the AD subgroup. NFL was significantly increased in the non-AD patients (p<0.001), and in the parkinsonian syndromes subgroup (p=0.016) when compared to negative controls. Serum p-tau181 and p-tau217 were significantly correlated with CSF p-tau181 (Spearman’s coefficients of 0.43 and 0.48 respectively, n=40). Areas under the ROC curves for the identification of patients with neurodegenerative diseases were 0.62 (0.54–0.70) for NFL, 0.62 (0.54–0.71) for T-tau, 0.83 (0.76–0.89) for p-tau217, and 0.66 (0.58–0.74) for Aβ40. Conclusions Serum biomarkers can help identify patients with neurodegenerative disease and may be a valuable tool for care and orientation. Phosphorylated tau p-tau217 is a promising blood biomarker for AD and NFL for other etiologies.