Bonini et al. (1996) postulated that NGF levels were elevated in patients with allergic inflammatory diseases and asthma. Forkhead Box P3 (FOXP3) is the transcriptional regulator critical to the development and inhibition of regulatory T-cells (Treg). Treg cells maintain immune system homeostasis by regulating other leukocytes (Lu et al., 2017). Here, NGF is linked to asthma.