Exosome fractions were purified from spinal fluid collected from Alzheimer's disease patients and control subjects using MagCapture. Elution of exosomes bound to affinity beads was performed with 1% SDS. Proteins were precipitated from the exosome fraction by acetone precipitation; the precipitates were dissolved in 50% trifluoroethanol and subjected to reduction with DTT and alkylation reaction with iodoacetamide. The proteins were degraded by trypsin/Lys-C, and the peptides produced were desalted and purified using MonoSpinC18. The peptides were measured by LC-MS/MS and quantified by non-label quantification method. The peak area values of peptide-proteins for each sample were normalized to the total peak area.