TNF and chronic obstructive pulmonary disease: We measured serum leptin, IGF-I, TNF-α, interleukin 1β (IL-1β), interleukin 6 (IL-6) and interleukin 8 (IL-8) levels in 52 COPD patients with acute exacerbation on admission to hospital (Day 1) and two weeks later (Day 15).