Effects of bacterial exposure on macrophage cytokine production. a–c) Monocyte-derived macrophages (MDMs) from 10 healthy nonsmokers (HNS) and eight COPD patients or d–f) lung macrophages (LM) from four ex-smokers (ES) and four COPD patients were exposed to Haemophilus influenzae (HI), Moraxella catarrhalis (MC) or Streptococcus pneumoniae (SP) at a multiplicity of infection (MOI) of 5:1 or left unexposed (Control) for 24 h. Supernatant levels of tumour necrosis factor-α (TNF-α), interleukin-6 (IL-6) and C-X-C motif chemokine ligand (CXCL8) were measured by ELISA. Data presented as mean+sem. Levels were compared between conditions using two-way ANOVA followed by a Bonferroni's multiple comparisons test. #,##,###: significantly above unexposed control (p<0.05, 0.01, 0.001 respectively). *,**,***: significant difference between bacterial species (p<0.05, 0.01, 0.001, respectively).