Urinary β2-microglobulin and bronchopulmonary dysplasia: Trends in preterm infants.

BACKGROUND: The developmental process of bronchopulmonary dysplasia (BPD) is not identical between very preterm infants born small for gestational age (SGA) and those born appropriate for gestational age (AGA). In this study, we compared the pattern of the inflammatory response in infants of each group, by measuring urinary β2-microglobulin (Uβ2M) as an alternative, concise, and less-invasive biomarker.

METHODS: Uβ2M and clinical details were examined at birth and at 4 weeks of age in 146 very preterm infants.

RESULTS: Of the 57 infants diagnosed with BPD, 18 were SGA, and 39 were AGA. Uβ2M at birth was significantly lower in SGA BPD infants than in AGA BPD infants, but it increased with time. The prevalence of chorioamnionitis (CAM) was significantly lower in SGA BPD infants than in AGA BPD infants, while that of pregnancy-induced hypertension was the opposite.

CONCLUSIONS: Exposure to prenatal factors other than CAM may sensitize fetal lungs to become vulnerable to postnatal inflammation in very preterm SGA infants with BPD.