Lung function development after preterm birth in relation to severity of Bronchopulmonary dysplasia

Background: Bronchopulmonary dysplasia (BPD) is a strong risk factor for respiratory morbidity in children born preterm. Our aims were to evaluate lung function in adolescents born preterm with and without a history of BPD, and to assess lung function change over time from school age. Methods: Fifty-one individuals born in Stockholm, Sweden between gestational ages 24 to 31 weeks (23 neonatally diagnosed with respiratory distress syndrome (RDS) but not BPD, and 28 graded as mild (n = 17), moderate (n = 7) or severe (n = 4) BPD) were examined in adolescence (13-17 years of age) using spirometry, impulse oscillometry (IOS), plethysmography, and ergospirometry. Comparison with lung function data from school age (6-8 years of age) was also performed. Results: Adolescents with a history of BPD had lower forced expiratory volume in 1 s (FEV1) compared to those without BPD (-0.61 vs.-0.02 z-scores, P < 0.05), with lower FEV1 values significantly associated with BPD severity (P for trend 0.002). Subjects with severe BPD had higher frequency dependence of resistance, R5-20, (P < 0.001 vs. non-BPD subjects) which is an IOS indicator of peripheral airway involvement. Between school age and adolescence, FEV1/FVC z-scores decreased in all groups and particularly in the severe BPD group (from -1.68 z-scores at 6-8 years to -2.74 z-scores at 13-17 years, p < 0.05 compared to the non-BPD group). Conclusions: Our results of spirometry and IOS measures in the BPD groups compared to the non-BPD group suggest airway obstruction including involvement of peripheral airways. The longitudinal result of a decrease in FEV1/FVC in the group with severe BPD might implicate a route towards chronic airway obstruction in adulthood

Large airway T cells in adults with former bronchopulmonary dysplasia

Abstract Background Bronchopulmonary Dysplasia (BPD) in infants born prematurely is a risk factor for chronic airway obstruction later in life. The distribution of T cell subtypes in the large airways is largely unknown. Objective To characterize cellular and T cell profiles in the large airways of young adults with a history of BPD. Methods Forty-three young adults born prematurely (preterm (n = 20), BPD (n = 23)) and 45 full-term-born (asthma (n = 23), healthy (n = 22)) underwent lung function measurements, and bronchoscopy with large airway bronchial wash (BW). T-cells subsets in BW were analyzed by immunocytochemistry. Results The proportions of both lymphocytes and CD8 + T cells in BW were significantly higher in BPD (median, 6.6%, and 78.0%) when compared with asthma (3.4% and 67.8%, p = 0.002 and p = 0.040) and healthy (3.8% and 40%, p < 0.001 and p < 0.001). In all adults born prematurely (preterm and BPD), lymphocyte proportion correlated negatively with forced vital capacity (r= -0.324, p = 0.036) and CD8 + T cells correlated with forced expiratory volume in one second, FEV1 (r=-0.448, p = 0.048). Correlation-based network analysis revealed that lung function cluster and BPD-birth cluster were associated with lymphocytes and/or CD4 + and CD8 + T cells. Multivariate regression analysis showed that lymphocyte proportions and BPD severity qualified as independent factors associated with FEV1. Conclusions The increased cytotoxic T cells in the large airways in young adults with former BPD, suggest a similar T-cell subset pattern as in the small airways, resembling features of COPD. Our findings strengthen the hypothesis that mechanisms involving adaptive and innate immune responses are involved in the development of airway disease due to preterm birth