Lung tissue expressed more CXCL-12, also known as stromal cell derived factor 1 (SDF-1),in ALI (Petty et al., 2007) and CXCR4 plays an important role in homing of aged neutrophils to bone marrow for clearance (Allen et al., 2004). The gene discussed is CXCL12; the disease is acute respiratory distress syndrome.