Clinical and animal studies have demonstrated increased neutrophils and macrophages in bronchoalveolar lavage fluid (27, 28) and tracheal aspirates from subjects with BPD (15) In this study, we found that antagonism of caspase-1 downregulated the expression of NLRP3 inflammasome proteins, leading to decreased macrophage infiltration in the alveolar spaces of lungs exposed to hyperoxia. The gene discussed is CASP1; the disease is bronchopulmonary dysplasia.