Studies have shown that the inducible expression of hBD2 gene may be associated with the development of acute lung injury (ALI), and its high concentration in lung secretion has protective effect on ALI [17]; In ARDS patients, defensing levels in BALF are highly correlated the level of IL-8, indicating that lung injury may be related to accumulation of neutrophils in the lung and the release of defensins [18]. The gene discussed is CXCL8; the disease is acute respiratory distress syndrome.