IL6 and chronic obstructive pulmonary disease: In addition to COPD patients, systemic inflammation can be found in patients who smoke, as evidenced by elevated systemic inflammatory markers such as C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), activated leukocytes, and fibrinogen; however, the degree of systemic inflammation is more pronounced in COPD patients (4, 91, 92).