TNF and chronic obstructive pulmonary disease: When the two subgroups of COPD patients were compared with each other, the levels of IL-1α, IL-6, TNF-α and IL-8 were higher in the COPD patients with a tobacco history than in the patients with post-TB airflow obstruction with p-values of 0.031; 0.049; 0.021 and 0.016 respectively, with no significant differences on the other cytokines (Fig. 1).