A polymorphism in the macrophage migration inhibitory factor promoter is associated with bronchopulmonary dysplasia.

Bronchopulmonary dysplasia (BPD) is a common adverse outcome of prematurity, causing severe morbidity and mortality. The cytokine macrophage migration inhibitory factor (MIF) has been recently shown to favor murine fetal lung development. In this prospective study, we evaluate the expression of MIF in the lung and in the serum of preterm infants (n = 50) and investigate whether the -173 G/C MIF promoter polymorphism is associated with the risk of BPD (n = 103). MIF was highly expressed in lung tissue from preterm infants. Serum MIF levels were measured by ELISA at d 1 after birth. MIF levels were increased [median (interquartile range), 71.01 (44.9-162.3) ng/mL], particularly in those infants with RDS [110.4 (59.4-239.2) ng/mL] compared with healthy adults [2.4 (1.2-5.0) ng/mL], (p < 0.001). The MIF -173C allele, which predisposes to higher MIF production, was associated with a lower incidence of BPD (OR, 0.2; 95% CI, 0.04-0.93), independently from mechanical ventilation and oxygen exposure (p = 0.03). In conclusion, these data show that MIF expression is increased in lung and serum of preterm infants and suggest that the high producing MIF -173C allele may be a protective factor for BPD.