Patterns of inflammatory airway cells in young adults with bronchopulmonary dysplasia: a study from large and small airways

<bold>Background:</bold> Bronchopulmonary Dysplasia (BPD) in preterm neonates predisposes to chronic airway obstruction later. <bold>Aim:</bold> To integrate inflammatory cell profiles from both small and large airways to identify consistent patterns and understand BPD's long-term effects. <bold>Methods:</bold> Forty-three young adults (20.4 years) born prematurely (preterm and BPD) and 45 full-term-born (asthma and healthy) (19.2 years) underwent bronchoscopy with sampling from large (bronchial wash (BW) and bronchial brushings (BB)) as well as small (bronchoalveolar lavage (BAL)) airways. <bold>Results:</bold> Inflammatory cell proportions (neutrophils, macrophages, lymphocytes, eosinophils) in BB were significantly higher in BPD subjects (median 11.7%) compared to asthma (6.2%, p=0.017) and healthy individuals (6.0%, p=0.017, Fig 1A). In the pooled group of asthma, preterm, and BPD, inflammatory cells in BB correlated negatively with FEV₁ (% predicted and z-score; p=0.023 and 0.016) and positively with lymphocyte counts in BAL (p = 0.009). Correlation-based network analysis revealed that the lung function-inflammatory cells cluster was associated with the lymphocytes-BPD cluster (Fig 1B) <bold>Conclusion:</bold> Adults with a previous BPD diagnosis have more inflammatory cells in the large airways and these cells are associated with reduced lung function. These findings suggest a pattern of persistent impact of BPD on airway inflammation.