Aportación del cociente Aß1-42/Aß1-40 al concepto ‘enfermedad de Alzheimer contribuye al deterioro cognitivo leve’

Abstract

Evidence of cerebral amyloidosis, by altered levels of the peptide Aß1-42 or the Aß1-42/Aß1-40 ratio, is a necessary condition to accept the presence of Alzheimer's disease (AD), according to the 2018 criteria of the National Institute on Aging and Alzheimer's Association (NIA-AA 2018). To calculate the diagnostic gain obtained from calculating the Aß1-42/Aß1-40 ratio with respect to the exclusive use of the peptide Aß42 to identify patients belonging to the 'Alzheimer's disease contributes to mild cognitive impairment (MCI)' group, according to NIA-AA 2018 criteria. Between April 2018 and April 2020, we included 62 patients with MCI, according to Petersen's 2006 criteria, who underwent lumbar puncture as part of the diagnostic process. Cerebrospinal fluid was analysed using the immunochemiluminescence methodology, which makes it possible to quantify core AD biomarkers in cerebrospinal fluid and the peptide Aß1-40. Forty-two patients (67.7%) presented criteria supporting 'AD contributes to MCI'. The use of the Aß1-42/Aß1-40 ratio, compared to the exclusive use of Aß1-42 levels, represents a diagnostic gain of 19% (eight patients) to establish the presence of amyloidosis in the cerebrospinal fluid of these patients. The calculation of the Aß1-42/Aß1-40 ratio is a clear diagnostic gain for identifying patients belonging to the 'AD contributes to MCI' group, and we therefore recommend its use, as reported in the most recent literature. To our knowledge, this is the first publication of its kind in Spanish.