GPI and bronchopulmonary dysplasia: The proteins with the greatest FC values in preterm infants with BPD were LBP, X-ray repair cross-complementing protein 6 (XRCC6), glucose-6-phosphate isomerase (GPI), Golgi membrane protein 1 (GOLM1), immunoglobulin kappa variable 1-5 (IGKV1-5), and I immunoglobulin kappa variable 1-33 (GKV1-33) (Figure 2).