Cytokines in sputum and serum from patients with cystic fibrosis and chronic Pseudomonas aeruginosa infection as markers of destructive inflammation in the lungs.

The presence of interleukin (IL)-1 receptor antagonist (IRAP) in plasma and sputum from patients with cystic fibrosis (CF) and chronic Pseudomonas aeruginosa lung infection was investigated together with IL-1 alpha, IL-1 beta, IL-6, and tumor necrosis factor-alpha (TNF) in a cross-sectional study. All cytokines were assayed by ELISAs. High concentrations of IRAP, IL-1 alpha, IL-1 beta, IL-6, and TNF in sputum samples and low or nondetectable levels of circulating cytokines were frequently found. Increased concentrations of plasma IRAP are positively correlated with decreasing pulmonary function. In a longitudinal study of serum IRAP, a higher level of IRAP was detected in a group of patients with poor pulmonary function compared to a group with good pulmonary function.