Reduced effect of intravenous antibiotic treatment on sinonasal markers in pulmonary inflammation.

BACKGROUND: Chronic bacterial rhinosinusitis is a common feature in Cystic fibrosis (CF) as mucociliary clearance in the sinonasal compartment is impaired. Aim of the present prospective study was to compare dynamics of inflammatory markers in the upper and lower airways (UAW/LAW) during systemic antibiotic therapy. METHODS: Nasal lavage and sputum of 16 CF-patients receiving an IV-antibiotic treatment against Pseudomonas aeruginosa and/ or Staphylococcus aureus were collected before and during treatment (median after 7.5 days). Cytological changes, DNA concentration, and inflammatory markers interleukin (IL)-4, IL-8, IL-13 and Myeloperoxidase (MPO) were assessed in samples from both airway compartments. RESULTS: Total cell count declined significantly in LAW-samples but not in UAW. Although MPO and IL-8 decreased significantly in both airway compartments, this was considerably more pronounced for LAW (median decrease MPO: LAW=9.8-fold vs UAW=1.75-fold, respectively; IL-8: LAW=3-fold vs UAW=1.9-fold, respectively). DISCUSSION: This is the first publication demonstrating substantially lower effects of IV-antibiotic treatment on sinonasal than on pulmonary inflammatory markers. Consequently, our findings highlight limitations of systemic antibiotic treatment to control infection in the sinonasal compartment. Primarily, we attribute this to the paranasal sinus ́ structure: these hollow organs, which in bacterial sinusitis are frequently filled with pus, mucoeceles and polyps, are not reached effectively by systemic antibiotic treatment.