FLT3LG and bronchopulmonary dysplasia: Finally, we show that in tracheal aspirates from human preterm infants mechanically-ventilated for respiratory distress in the first week of life, levels of FLT3L, IL-12p40, IL-12p70 and IFN-γ are higher in infants who go on to develop BPD compared to infants who do not develop BPD.