IL-6 and IL-8 levels in sputum also increased slightly during AE-COPD, but did not reach statistical significance (IL-6: stable, 117.1 ± 108.2 pg/mL vs. during AE-COPD, 225.9 ± 193.5 pg/mL; IL-8: stable, 3.7×103 ± 2.6×103 ng/mL vs. AE-COPD, 5.5×103 ± 4.3×103 ng/mL; mean ± SD, p = 0.16 for both analytes). This evidence concerns the gene CXCL8 and chronic obstructive pulmonary disease.