NF-κB, IL-6, IL-8 and TNF-α, all of which have the characteristics of high potency and synergistic and mutual induction, resulting in the amplification of the inflammatory cytokine cascade, which can, in turn, lead to the production of oxygen free radicals, form a vicious circle, aggravate lung tissue, and induce persistence of the chronic inflammatory state of COPD. This evidence concerns the gene IL6 and chronic obstructive pulmonary disease.