To remove high-abundance proteins, 32 serum samples (9 samples before OFC, 9 samples 1 h after OFC, 9 samples 2 h after OFC, and 5 samples at symptom onset) were treated using Top14 Abundant Protein Depletion Mini Spin Columns (Thermo Fisher Scientific) following the manufacturer’s instructions. The filtrates were dissolved in 100 mM Tris-HCl (pH 8.0) containing 4% SDS, 20 mM NaCl, and 10% ACN using the Bioruptor BR-II. The reduction and alkylation of proteins and the SP3 method were performed as previously described. Peptides were dissolved in 0.01% DMNG containing 0.1% TFA.