Cytokine profiles at birth and the risk of developing severe respiratory distress and chronic lung disease

BACKGROUND Neonates with the diagnosis of respiratory distress syndrome (RDS) were studied to investigate possible associations between cytokine levels at birth and developing severe RDS or chronic lung disease (CLD). MATERIALS AND METHODS This was a cross-sectional study on serum and bronchoalveolar lavage (BAL) samples collected within hours of birth from infants with moderate and severe RDS. Twenty infants with moderate RDS and 20 infants with severe RDS were studied. RDS was diagnosed on the basis of radiographic findings, respiratory distress, and an increasing oxygen requirement. RDS severity was graded based on the radiological findings and Downe's Score. CLD was diagnosed when infants were still on supplemented O2 by at least 28 days of age. Levels of the cytokines interleukin (IL)-1β, IL-6, IL-8, IL-10, and tumor necrosis factor alpha were measured using enzyme-linked immunosorbent assay. "Statistical analysis was performed using the SPSS for Windows, (SPSS Inc., Chicago, IL, USA)." RESULTS Levels of the proinflammatory cytokines IL-8 and IL-1β were significantly higher in BAL of infants with severe RDS than those with moderate RDS (P = 0.007 and P = 0.02, respectively). IL-8 levels were also significantly higher in BAL and serum of infants who later progressed to CLD than in those who did not (P = 0.03 for both). The IL-8/IL-10 cytokine ratio was significantly higher in the BAL of severe RDS infants than in moderate RDS (P = 0.01) and in the serum of infants who progressed to CLD than in those who did not (P = 0.03). CONCLUSION Levels of IL-8 and the IL-8/IL-10 ratio measured soon after birth were associated with severity of RDS as well as progression to CLD. Early measurement of cytokines levels and ratios may contribute to the prognosis and management of RDS and CLD.