Factors involved in the progression of COPD and the deterioration of pulmonary function, among which the theory of inflammatory factors has been recognised by many scholars, are incomplete.24,25 The inflammatory factor TNF-α is mainly produced by monocytes and macrophages and is the earliest and most important major endogenous mediator released in the inflammatory response.26 By contrast, LTB4 serves as an important mediator in the pathogenesis of COPD; it is also a potent inflammatory transmitter secreted by lymphocytes, macrophages, neutrophils and other inflammatory cells. Here, TNF is linked to chronic obstructive pulmonary disease.