Cerebrospinal fluid biomarkers of Alzheimer's disease in Lewy body diseases: The performance of fully automated immunoassays.

BackgroundThe potential role of Alzheimer's disease (AD) pathology in contributing to cognitive impairment in α-synucleinopathies warrants in vivo detection of the pathological burden in patients with α-synucleinopathies.ObjectiveUsing a fully automated platform, we measured the levels of cerebrospinal fluid (CSF) AD biomarkers, namely Aβ42, P-tau181 and T-tau, as well as their derived ratios, P-tau181/Aβ42 ratio and T-tau/Aβ42 ratio, in a cohort of Parkinson's disease (PD), dementia with Lewy bodies (DLB), preclinical and prodromal AD (pAD) patients, as well as cognitively normal controls. We binarized the CSF biomarkers and determined the proportion of individuals with abnormal biomarker levels within each diagnostic group. We explored the associations between these biomarkers and cognitive performance.MethodsThis study consisted of 51 controls, 46 PD, 65 DLB, and 50 pAD patients. CSF biomarkers were measured using Roche Elecsys® immunoassays. Cognitive performance was based on Mini-Mental State Examination (MMSE).ResultsCSF P-tau181/Aβ42 and T-tau/Aβ42 ratios were increased in DLB and pAD, but not PD, compared with controls. Both DLB and pAD had higher proportions of individuals with abnormal CSF P-tau181/Aβ42 ratio (AD = 100%, DLB = 59%, PD = 37% and controls = 26%) and T-tau/Aβ42 ratio (AD = 100%, DLB = 51%, PD = 26% and controls = 18%). Within each diagnostic group, there was no association between CSF AD biomarkers and cognition.ConclusionsCSF AD biomarkers profile is prevalent in DLB. Our findings highlight the potential utility of Elecsys® immunoassay platform for the evaluation of AD pathology in α-synucleinopathies.