Epithelial cells are the airway’s first line of defense against inhaled allergens and pathogens, and epithelial damage initiates airway inflammation57; pulmonary macrophages are dysfunctional in allergic asthma and are major sources of TNF-α, IL-1β, IL-6 and IL-858; and vascular endothelial cells may contribute to airway inflammation and remodeling through eotaxin, IL-1α, GM-CSF, and VEGF59. The gene discussed is CSF2; the disease is allergic asthma.