Alveolar macrophages from COPD and smokers (13 COPD and 10 smokers) were left untreated, supernatants were collected after 24 h and assayed for TNF-α (A), IL-6 (B), CXCL8 (C) and IL-10 (D) release by ELISA. Here, CXCL8 is linked to chronic obstructive pulmonary disease.