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‐lα, IL‐1β, IL‐6, and tumor necrosis factor‐α (TNF) in a cross‐sectional study. All cytokines were assayed by ELISAs. High concentrations of IRAP, IL‐lα, IL‐1β, IL‐6, and TNF in sputum samples and low or nondetectable levels of circulating cytokines were frequently found. Increased concentrations of plasma RAP are positively correlated with decreasing pulmonary function. In a longitudinal study of serum IRAP, a higher level of RAP was detected in a group of patients with poor pulmonary function compared to a group with good pulmonary function. © 1993 Wiley‐Liss, Inc.