IFNG and chronic obstructive pulmonary disease: Concentrations of IFN-γ were significantly increased in COPD + DS patients when compared with controls (24.3 ± 1.49 and 17.8 ± 0.70 pg/ml, respectively, p < 0.05) and also when compare to rDD patients (18.1 ± 1.43 pg/ml, p < 0.05),(Fig. 1b).