In allergic asthma, airway inflammation is mainly characterized by Th2-mediated processes, including secretion of the cytokines IL-4, IL-5, IL-6, IL-9 and IL-13, secretion of chemokines, regulation of the activation of normal T cells (RANTES), and production of granulocyte macrophage colony-stimulating factor (GM-CSF). This evidence concerns the gene IL5 and allergic asthma.