The levels of proinflammatory cytokines in BAL fluid from patients with COPD (IL-1β: 143.4 (37.9), TNF-α: 205.7 (46.1), TGF-β: 89.5 (35.1), EGF:104.3 (40.7) and IL-8: 216.8 (38.9) pg/ml) were also significantly higher than those from controls (IL-1β: 29.8 (13.6), TNF-α: 30.5 (17.2), TGF-β: 17.4 (8.5), EGF: 21.3 (11.6) and IL-8: 40.2 (18.3) pg/ml; fig 2B). Here, EGF is linked to chronic obstructive pulmonary disease.