PT - JOURNAL ARTICLE AU - Pernilla Glader AU - Barbro Dahlén AU - Bo Billing AU - Lena Palmberg AU - Ann-Sofie Lantz AU - Kjell Larsson AU - Anders Lindén TI - Increase of extracellular IL-17A and anti-microbial peptides in the peripheral airways of smokers DP - 2011 Sep 01 TA - European Respiratory Journal PG - p733 VI - 38 IP - Suppl 55 4099 - http://erj.ersjournals.com/content/38/Suppl_55/p733.short 4100 - http://erj.ersjournals.com/content/38/Suppl_55/p733.full SO - Eur Respir J2011 Sep 01; 38 AB - Among several known cytokine-signalling pathways influencing innate effector cells, T helper (Th) 17 cytokines have emerged as particularly interesting for the understanding of chronic inflammatory conditions. Cigarette smokers suffer from frequent infections, are often colonised with bacteria in their lower airways and display signs of chronic inflammation including increased tissue expression of the Th17 cytokine IL-17A. We evaluated whether long-term current cigarette smokers display increased extracellular concentrations of Th17 cytokines and how this relates to anti-microbial peptides in the peripheral airways.Concentrations of IL-17A, -17F and -22 plus the downstream effector molecules human beta-defensin 2 (HBD2) and LL-37 (cathelicidin) were measured in bronchoalveolar lavage (BAL) fluid from non-smokers and from smokers with and without COPD (n=17-20/group). All study subjects were free from airway infections during the last 4 weeks prior to the study.The extracellular IL-17A concentrations (median [range]) were higher in smokers without COPD (1.2 [0.3-3.5], pg/ml) than in non-smokers (0.4 [0.1-4.4, pg/ml]; p<0.05). Smokers with COPD displayed intermediate concentrations of IL-17A (0.7 [0.1-7.1], pg/ml) Compared to non-smokers (22 [4-384], pg/ml), HBD2 was higher in smokers without COPD (70 [6-500], pg/ml; p<0.05), but not in smokers with COPD (24 [4-364], pg/ml). Interleukin-17F, IL-22 and LL37 were undetectable in most of the samples.In conclusion, long-term cigarette smokers without COPD display increased extracellular concentrations of IL-17A, and this may be linked to increased concentrations of the anti-microbial peptide HBD2.