Added 8 M urea solution to the frozen plasma sample, quantified and enriched the low-abundance proteins were using the ProteoMiner™ Protein Enrichment Kit (Bio-Rad, Hercules, USA). Added triethylammonium bicarbonate buffer (TEAB) to a 100 μg sample to reach a final concentration of 100 mM, along with tris-(2-carboxyethyl) phosphine at a final concentration of 10 mM. Incubated this mixture at 37 ℃ for 60 min, and subsequently added iodoacetamide to a final concentration of 40 mM, reacted for 40 min at room temperature in the dark. After centrifuging for 20 min at 10,000 G, dissolved the precipitate in 100 μL of 100 mM TEAB, and digested the proteins with trypsin (m/m, 1:50) at 37 ℃ to obtain peptide segments, which were then dried in a vacuum centrifugal concentrator (Taicang Huamei Biochemical Instrument Factory, Taicang, China) and redissolved in a solution containing 1% trifluoroacetic acid. Desalted the peptide segments using a hydrophilic-lipophilic balance and quantified them following the kit instructions (Thermo Fisher Scientific, Waltham, USA) after drying in a vacuum centrifugal concentrator. Finally, dissolved these peptide segments in loading buffer for downstream analyses.