CCL20 and asthma: It is necessary for the production of pro-inflammatory cytokines and chemokines, such as CC-​chemokine ligand 20 (CCL20)/macrophage inflammatory protein (MIP)-3α, granulocyte-macrophage colony-stimulating factor (GM-CSF), thymic stromal lymphopoietin (TSLP), IL-8, IL-25, and IL-33, which are significantly upregulated in patients with allergic pulmonary inflammation or asthma in response to inhaled stimuli (72–74).