RESUMO
BACKGROUND: Dementia with Lewy bodies (DLB) symptoms are close to those of Alzheimer's disease (AD), and the differential diagnosis is difficult especially early in the disease. Unfortunately, AD biomarkers in cerebrospinal fluid (CSF), and more particularly Aß1 - 42, appear to be altered in dementia with Lewy bodies (DLB). However, the level of these biomarkers has never been studied in the prodromal stage of the disease. OBJECTIVE: To compare these biomarkers between DLB and AD, with a particular focus on the prodromal stage. METHODS: A total of 166 CSF samples were collected at the memory clinic of Strasbourg. They were obtained from prodromal DLB (pro-DLB), DLB dementia, prodromal AD (pro-AD), and AD dementia patients, and elderly controls. Phospho-Tau181, total-Tau, Aß42, and Aß40 were measured in the CSF. RESULTS: At the prodromal stage, contrary to AD patients, DLB patients' biomarker levels in the CSF were not altered. At the demented stage of DLB, Aß42 levels were reduced as well as Aß40 levels. Thus, the Aß42/Aß40 ratio remained unchanged between the prodromal and demented stages, contrary to what was observed in AD. Tau and Phospho-Tau181 levels were unaltered in DLB patients. CONCLUSIONS: We have shown that at the prodromal stage the DLB patients had no pathological profile. Consequently, CSF AD biomarkers are extremely useful for differentiating AD from DLB patients particularly at this stage when the clinical diagnosis is difficult. Thus, these results open up new perspectives on the interpretation of AD biomarkers in DLB.
