IL15 and pulmonary emphysema: Regression coefficients showed that, compared to smokers without emphysema, subjects with emphysema had lower levels of EGF (−0.317, p = 0.01), IL-15 (−0.219, p = 0.01), IL-8 (−0.180, p = 0.02), and IL-1ra (−0.220, p = 0.03).