Neonatal rodents with experimental BPD have unchanged lung SDF-1 expression [34], while lung tissue of patients with idiopathic pulmonary fibrosis have an increased number of SDF-1 expressing cells and blockade of the SDF-1 receptor, CXCR4, decreases pulmonary fibrosis [19]. Here, CXCR4 is linked to pulmonary fibrosis.