Cytokine levels in sputum of cystic fibrosis patients before and after antibiotic therapy

It is not known whether cytokine levels in sputum may be used as outcome measures after parenteral antibiotic therapy in cystic fibrosis (CF) patients. Here, we assessed the effects of antibiotic therapy on cytokine levels in sputum and serum obtained from young CF patients. Thirty-two CF patients (14 females; mean age, 18.6 years; range, 11.4-35.7 years), consecutively admitted at the CF Center of Milan for parenteral antibiotic therapy during pulmonary exacerbation, were enrolled in the study. Before and after 21 days (range, 5-41) of intravenous antibiotic treatment, all patients underwent routine laboratory determinations (including white blood cell (WBC) count and C-reactive protein (CRP)), a chest X-ray, pulmonary function tests (forced expiratory volume in 1 sec (FEV1) and forced vital capacity (FVC) as % predicted), and sputum cultures. Interleukin (IL)-6, IL-8, IL-10, and tumor necrosis factor (TNF)-alpha levels in serum and sputum samples were determined by means of immunometric assays. After therapy, FEV1 and FVC significantly improved (median increase of 7.5% and 8.5% predicted, respectively), while CRP and WBC count were significantly decreased (median values from 14 to 5.5 mg/dl and from 8,350 to 7,400 n/mm3, respectively). While levels of IL-6 and IL-10 in sputum were generally undetectable, IL-8 and TNF-alpha were always measurable, and IL-8 levels significantly decreased after antibiotic treatment (median values from 7,165 to 5,415 pg/ml). Following antibiotic therapy, IL-8 and TNF-alpha levels in sputum were inversely related with both FEV(1) and FVC. In conclusion, TNF-alpha and IL-8 levels in sputum of young CF patients with pulmonary exacerbation were always detectable and may be useful, noninvasive outcome measures to assess response to therapy in CF patients.