TY - JOUR T1 - Comparison of inflammatory markers in induced and spontaneous sputum in COPD patients JF - European Respiratory Journal JO - Eur Respir J VL - 44 IS - Suppl 58 SP - P842 AU - Solveig Tangedal AU - Marianne Aanerud AU - Louise Persson AU - Karl A. Brokstad AU - Per Bakke AU - Tomas Eagan Y1 - 2014/09/01 UR - http://erj.ersjournals.com/content/44/Suppl_58/P842.abstract N2 - Background: Sputum induction is a method for obtaining non-invasively and reliable measurements of inflammation in the airways. Whether spontaneously sampled sputum is a valid surrogate for induced sputum is unknown. We wanted to compare levels of 6 inflammatory markers in induced and spontaneous sputum sampled on the same consultation either at the steady state or during exacerbations of COPD.Methods: 433 COPD patients aged 40 - 76, GOLD stage II-IV were enrolled in 2006/07 and followed every 6 months and at exacerbations for 3 years. 45 patients delivered 60 paired sputum samples for analysis. IL-6, IL-8, IL-18, IP-10, TNFα and MIG were measured by a bead based multiplex immunoassay. 24 samples were cultured.Results: TNFα was significantly higher when measured in spontaneous sputum both at exacerbations and at steady state (p<0.01). IL-18 and MIG were higher in spontaneous sputum, but statistically significant for IL-18 only at exacerbations (p=0.04) and for MIG only at stable state (p=0.02). Correlation coefficients between markers in induced and spontaneous sputum varied between 0.551 for IL-18 to 0.838 for IP-10. In spontaneous sputum IL-18 and MIG were higher in ex-smokers (p<0.05). In both sputum types the levels of all markers except IL-6, were higher in GOLD stage III & IV compared with GOLD stage II, although not statistically significant. In spontaneous sputum samples the levels of IL-6 was significantly higher if H.Influenzae was cultured.Conclusion: We observed significant differences in inflammatory markers between induced and spontaneous sputum, both at steady state and exacerbations. We recommend that sampling method is considered when reporting on inflammatory markers in sputum. ER -