title: Infrared spectroscopic analysis of mononuclear leukocytes in peripheral blood from Alzheimer's disease patients.
abstract: Peripheral mononuclear leukocytes from Alzheimer's disease (AD) patients were analyzed by infrared spectroscopy and their spectroscopic properties were compared with those from age-matched healthy controls. Two-dimensional correlation analysis of mean spectra measured at various disease stages shows that the protein secondary structure from AD patients involves β-sheet enrichment and carbonyl intensity increase relative to healthy controls. The area percentages of β-sheets, which were obtained by using a peak ratio second-derivative spectral treatment, were used for receiver operating characteristic (ROC) analysis to distinguish between patients with AD and age-matched healthy controls. The critical concentration and area under the curve (AUC) were determined by this curve analysis which showed a good performance for this quantitative assay. The results were 90% sensitivity and 90.5% specificity for determinations involving mild and moderate AD patients, and 82.1% sensitivity and 90.5% specificity for determinations involving patients at the three AD stages (mild, moderate, and severe). The AUC was greater than 0.85 in both scenarios. Taken together these results show that healthy controls are distinguished from mild and moderate AD patients better than from patients with severe disease and suggest that this infrared analysis is a promising strategy for AD diagnostics.
authors.affiliation: Instituto de Estructura de la Materia, CSIC, Madrid, Spain. p.carmona@iem.cfmac.csic.es
authors.forename: Pedro
authors.initials: P
authors.lastname: Carmona
authors.forename: Marina
authors.initials: M
authors.lastname: Molina
authors.forename: Miguel
authors.initials: M
authors.lastname: Calero
authors.forename: Félix
authors.initials: F
authors.lastname: Bermejo-Pareja
authors.forename: Pablo
authors.initials: P
authors.lastname: Martínez-Martín
authors.forename: Isabel
authors.initials: I
authors.lastname: Alvarez
authors.forename: Adolfo
authors.initials: A
authors.lastname: Toledano
mesh_terms: D000544:Alzheimer Disease / Q000175:diagnosis / Q000378:metabolism*; D019540:Area Under Curve; D005260:Female; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000737:chemistry*; D008297:Male; D017433:Protein Structure, Secondary; D011506:Proteins / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*
chemical_list: D011506:Proteins