CASP3 and idiopathic pulmonary fibrosis: To further confirm these findings, we used lung fibroblasts obtained from patients suffering from IPF and transfected them either with SDF-1β or control plasmid and observed similar findings as in vivo; that is, a reduced number of myofibroblasts, increased caspase 3-positive myofibroblasts and a relative increase of TNF-α after SDF-1β transfection in vitro.