Sample collection
fasting venous blood samples
The present study collected 10 mL of fasting venous blood samples from each subject from 6 a.m. to 8 a.m. using heparin anticoagulant tubes. The blood samples were then divided into two parts: one part was centrifuged for 15 min (3000 g, 4 °C) and stored at − 80 °C for further analysis; the other part was used for preparation of peripheral blood mononuclear cells (PBMCs) to complete further detection. Moreover, the electrochemiluminescence immunoassay method was used to measure eosinophil cationic protein (ECP) in the subjects’ serum. The present study completed nasal lavage using the method described in a previous study [