TFF2 and asthma: To determine the neuropeptide expression in patients with asthma, the peripheral blood of patients with asthma was tested using qRT-PCR for the expression of relevant neuropeptides, including SP, neurokinin A (NKA), NKB, calcitonin gene-related peptide (CGRP), vasoactive intestinal polypeptide (VIP), gamma-aminobutyric acid (GABA), and neuropeptide Y (NPY).