IL27 and chronic obstructive pulmonary disease: The rs153109 (− 964 A > G) polymorphism located 964 bp upstream of the transcription start site of the IL-27 gene has been demonstrated to be a potentially functional polymorphism that may alter transcription and expression of IL-27, leading to a genetic predisposition to many inflammatory diseases, such as ulcerative colitis, chronic obstructive pulmonary disease (COPD) and rheumatoid arthritis [21–23].