TNF and chronic obstructive pulmonary disease: In this present study, there was a significant increase in the number of neutrophils in BALF, and in the levels of pro-inflammatory cytokines IL-1 β, IL-6, IL-8, IL-10 and TNF-α in BALF supernatants obtained from AECOPD patients, compared with stable COPD patients and HS; and there was a positive correlation between the load of Klebsiella pneumoniae, Haemophilus influenzeae, Moraxella catarrhalis and Pseudomonos aeruginosa, and most inflammatory mediators.