TNF and chronic obstructive pulmonary disease: The levels of IL-1β, TNF-α, IL-6 and IL-17 in BALF of COPD rats decreased gradually with the increase of the dosage of Feikang granules, and the difference was statistically significant (F = 20.43, P < 0.001; F = 48.59, P < 0.001; F = 70.57, P < 0.001; F = 66.36, P < 0.001).