A previous study found that NGF that normally controls the survival, proliferation, and growth of neuronal cells, could also promote lung epithelial cells to survive during respiratory syncytial virus infection, with overexpressed NGF and its high-affinity receptor TrkA and concomitant downregulation of the low-affinity receptor p75 (28). The gene discussed is NTRK1; the disease is respiratory syncytial virus infectious disease.