Isolation of PBMCs
20ml peripheral blood would be collected from the patient before provocation and 24h, 72h after allergen nasal challenge. Peripheral blood was collected in the heparin anticoagulant according to a standard manner, then transferred to a 50 mL centrifuge tube and diluted with 20 mL PBS. 2.5 mL Ficoll-Hypaque Solution (Meijingbio, China) were added to the tube and mixed gently. Centrifuge at 400g for 25 minutes, and transfer PBMC cell layer to another tube. Add enough HBBS and mix thoroughly. After centrifuging at 300g for 5 minutes, the supernatant was discarded and the cell pellet was re-suspended in HBSS to repeat the centrifuging again.