Results In responders (n=9 PDmax dose), lung function returned to pre-challenge values by 3?h but was significantly decreased at 6 and 24?h in three of the responders (i.e. late-phase response) and induced sputum eosinophils were increased at NLG 919 24?h post-challenge (P<0.05). Responders showed enhanced bronchial airway deposition of inhaled particles (P<0.05) and slowed clearance from the central lung zone (P<0.01) at 4?h post-challenge compared with the baseline (no allergen challenge) that was predicted by the PDmax allergen concentration (r=?0.70, P<0.05). The decline in lung function at 24?h post-challenge correlated with reduced MCC from the central lung zone (r=?0.78, P<0.02) and PDmax. Non-responders (n=3) showed no change in lung function, regional deposition or MCC post-challenge vs. baseline. Conclusions and Clinical Relevance These data suggest that regional deposition and clearance of inhaled particles may be sensitive for detecting mild airway obstruction associated with early- and late-phase allergen-induced effects on mucus secretions. The study was listed on clinicaltrials.gov (NCT00448851). Cite this as: W. D. Bennett, M. Herbst, N. E. Alexis, K. L. Zeman, J. Wu, M. L. Hernandez, and D. B. Peden, Clinical & Experimental Allergy, 2011 (41) 1719?C1728. ""The role of non-invasive methods in the investigation of acute effects of traffic-related air pollution is not clearly established. We evaluated the usefulness of non-invasive biomarkers BMN 673 cell line in detecting acute air pollution effects according to the age of participants, the disease status, their sensitivity compared with lung function tests Selleckchem PLX3397 and their specificity for a type of pollutant. Search terms lead to 535 titles, among them 128 had potentially relevant abstracts. Sixtynine full papers were reviewed, while 59 articles were excluded as they did not meet the selection criteria. Methods used to assess short-term effects of air pollution included analysis of nasal lavage (NAL) for the upper airways, and induced sputum (IS), exhaled breath condensate (EBC) and exhaled nitric oxide (FeNO) for central and lower airways. There is strong evidence that FeNO evaluation is useful independently from subject age, while IS analysis is suitable almost for adults. Biomarker changes are generally observed upon pollutant exposure irrespective of the disease status of the participants. None of the biomarkers identified are specific for a type of pollutant exposure. Based on experimental exposure studies, there is moderate evidence that IS analysis is more sensitive than lung function tests, whereas this is not the case for biomarkers obtained by NAL or EBC.