IL17A and chronic obstructive pulmonary disease: The levels of inflammatory mediators, such as TNF-α, IL-6, IL-8, IL-17, and CRP, in the serum of COPD patients were highly expressed, and the lung structure was damaged due to the increased levels of inflammatory cytokines, resulting in the accumulation of a large number of T lymphocytes and neutrophils in the respiratory mucosa and causing airway reactions [61–63].