IL6 and chronic obstructive pulmonary disease: Concentrations of IL-6 were significantly increased in rDD, COPD, and COPD + DS groups when compared with controls: 40.9 ± 2.12 pg/ml (p < 0.05); 42.2 ± 1.87 pg/ml (p < 0.05); 41.7 ± 1.31 (p < 0.05) versus 33.2 ± 1.23 pg/ml, respectively, (Fig. 2a).