After infection, the airway epithelium responds by activating different signaling pathways, leading to the release of interleukin IL-8, regulated on activation, normal T cell expressed and secreted (RANTES, also known as CCL5), and granulocyte-macrophage colony-stimulating factor (GM-CSF), which in turn again recruits neutrophils (55). The gene discussed is CCL5; the disease is infection.