Since the first observations of cytologic changes in the tracheal aspirates of preterms developing BPD, a plenty of studies has detected an association between higher levels of typical pro-inflammatory cytokines like IL-1β, IL-6, IL-8, TNF-α, monocyte chemo-attractant proteins, and macrophage inflammatory proteins in the tracheal aspirate of the mechanically ventilated preterm infant and the later development of BPD [26, 27]. This evidence concerns the gene TNF and bronchopulmonary dysplasia.