In addition, IL-6, as a marker of airway inflammation, and 8-hydroxy-20-deoxyguanosine (8-OHdG), which indicates oxidative DNA damage, were higher in tracheal aspirates of preterm ventilated infants with BPD on postnatal days 1 and 28 compared with preterm infants without BPD [39]. Here, IL6 is linked to bronchopulmonary dysplasia.