Role of interleukin-6, its receptor and soluble gp130 in chronic lung disease of prematurity.

BACKGROUND

Interleukin-6 (IL-6) signalling involves the interplay between IL-6, soluble IL-6 receptor (sIL-6R) and soluble gp130 (sgp130). IL-6 activity is modulated by the soluble receptors to produce both pro- and anti-inflammatory effects in human diseases and animal models. The expression and functional activity of these molecules in lungs of preterm ventilated infants is unknown.

OBJECTIVES

We investigated this pathway in preterm infants who were at risk of developing chronic lung disease of prematurity (CLD).

METHODS

Cytokines and soluble receptors were measured in bronchoalveolar lavage fluid (BALF) from ventilated preterm infants ≤32 weeks of gestation who did or did not develop CLD. B9 cells, which specifically proliferate to IL-6, were used to assess BALF IL-6 functional activity.

RESULTS

Inflammatory cells, IL-8 and monocyte chemotactic protein-1 were increased in BALF from the CLD group when compared to the No CLD group (p < 0.05). BALF IL-6 and sIL-6R were similar in both groups. In contrast, BALF sgp130 and sgp130/sIL-6R were greater in the CLD group when compared to the No CLD group (p = 0.01 and p = 0.02, respectively). However, the increased BALF sgp130 did not appear to modulate the BALF IL-6 functional activity.

CONCLUSION

Lung inflammation was observed in the CLD group. Increased BALF sgp130 was noted in the CLD group but it did not appear to modulate the pulmonary IL-6 bioactivity. Further research is needed to investigate the potential modulatory activity of sgp130 in the preterm lung.