Quantitation of inflammatory responses to bacteria in young cystic fibrosis and control patients

Recent studies suggest that inflammation plays a role in the pathogenesis o f lung disease in cystic fibrosis (CF). The goal of the present study was t o quantitatively compare bronchoalveolar ravage fluid (BALF) inflammation a nd its relation to bacterial infection, between children with CF and childr en with other chronic respiratory problems. Differential cell counts, immun oreactive interleukin 8 (IL-8), and quantitative bacterial cultures were do ne in BALF from 54 CF (median age 1.8 yr) and 55 control patients (median a ge 1.0 yr) who underwent bronchoscopy for clinical indications. Among infec ted CF patients, those with Pseudomonas aeruginosa did not have more inflam mation than those without P. aeroginosa. The ratio of neutrophils or of IL- 8 to bacteria in BALF was significantly greater for CF patients compared wi th control subjects, regardless of pathogen. Calculation of linear regressi on for either neutrophils or IL-8, as a function of bacterial quantity, yie lded positive slopes for both CF and control patients, but with significant elevations for CF. We conclude that the inflammatory response to bacterial infection is increased or prolonged in CF compared with control patients, and that this increase is not necessarily due to pathogens specific for CF (e.g., P. aeruginosa). These data may provide further rationale for anti-in flammatory therapy early in CF.