AGT and asthma: Rare variants in the AGT gene are a major cause of asthma susceptibility in African Americans.[34] PTHLH is a gastrin-regulated growth factor that aids in maintaining gastric epithelial homeostasis and also promotes the epithelial mesenchymal transition of intestinal epithelial cells.[35,36] Interestingly, some scholars have postulated[37] that the intestine is a key site for the development of immune cells, and studying the interactions between the gut microbiota and immune cells can provide potential targets for the treatment of asthma.