Immune profiles and growth outcomes in very and extremely preterm infants with bronchopulmonary dysplasia: A prospective cohort study

Background Preterm birth is associated with immune dysregulation, and bronchopulmonary dysplasia (BPD) is the most prevalent complication affecting preterm infants. However, studies addressing the correlation between immune profiles and BPD severity in preterm infants remain limited. Methods A total of 78 preterm infants born at less than 32 weeks of gestation and 46 full-term controls were enrolled. Basic characteristics, including birth data, medical history, and growth, and immune profiles including CD3+ T cells and subsets of CD4+ and CD8+ T cells, along with CD19+ B cells, were analyzed and compared across various gestational age (GA) and BPD grading groups. Results Extremely preterm infants and those with severe BPD had lower birth weights, lower body weight percentiles, and higher rates of sepsis at 6 months corrected age compared with full-term infants and those with no or mild BPD ( P < 0.01). Among preterm infants, extremely preterm infants exhibited higher CD8+ T cell percentages with lower CD4/CD8 ratios than very preterm infants ( P < 0.05). Infants with severe BPD had the highest percentage of CD4/CD8 ratios below the 25th percentile among BPD grading groups ( P < 0.05). Furthermore, males had lower CD4+ T cell percentages than females ( P < 0.05), but no differences in immune profiles were found between those with or without sepsis. Conclusions Extremely preterm infants with severe BPD showed underdeveloped growth, higher sepsis rates, and altered high CD8+ T cells with lower CD4/CD8 ratios, which is potentially related to premature pulmonary processes in early infancy.