As in other chronic diseases characterized by chronic neutrophilic airway inflammation, like cystic fibrosis (15, 55) and diffuse panbronchiolitis (56), we demonstrate that a high concentration of α-defensins, despite their beneficial antibacterial effect (57), exacerbates airway injury by inducing the expression of inflammatory cytokines, CXCL8, IL-1b, and TNFα, not only in epithelial cells, but also in airway macrophages. The gene discussed is CXCL8; the disease is cystic fibrosis.