CXCL8 and chronic obstructive pulmonary disease: Only IL-8 (3 and 5 mg/kg infliximab groups combined) and IGF-1 (5 mg/kg infliximab group only) demonstrated trends, with high variability, for being decreased by ≥ 50% (p = 0.035 and 0.037, respectively) after infliximab treatment relative to placebo; however, IGF-1 was expressed at lower levels in COPD patients compared with controls, and IL-8 was not significantly elevated in COPD patients.