Exhaled leukotriene B4 in children with community acquired pneumonia.

BACKGROUND: The infiltrate in pneumonia is characterized by a large number of activated neutrophils, for which leukotriene B4 (LTB4) is a strong chemotactic agent. Exhaled breath condensate (EBC) is a non-invasive technique for studying the lower airways. The present study was conducted to measure EBC LTB4 as a potential non-invasive marker of inflammatory response in community acquired pneumonia (CAP). METHODS: Eighteen children with CAP and 17 healthy children were recruited (age 5-13). The CAP children underwent physical examination, chest X-ray, leukocyte count and C-reactive protein measurement. The CAP and the control children performed spirometry, exhaled nitric oxide measurement (FE(NO)) and EBC collection for LTB4 assessment. In the CAP children spirometry, FE(NO) and EBC collection were repeated twice over a 1-month follow-up. RESULTS: LTB4 EBC concentrations were higher in children with CAP than in healthy controls (10 pg/ml [7.0-15.3] vs. 3 pg/ml [3.0-6.9], P = 0.001) and decreased after 1 week (3 pg/ml [3.0-7.2], P < 0.01) with no further change a month later. In the acute phase spirometry demonstrated a restrictive pattern that gradually improved later. No difference in FE(NO) levels was found between children with CAP and healthy controls. CONCLUSION: Exhaled LTB4 levels increase in CAP and return to normal after 1 week. EBC collection is feasible in children with CAP and may represent a new way to non-invasively monitor the lung's biological response to infections.