This results in increased CD8+ T-cell-mediated cytotoxicity.22 IL-27 also drives inducible regulatory T cells to produce IL-10.23 Although we observed a significant increase in the number of IL-10+ cells in bronchial submucosa of patients with COPD and healthy smokers, these numbers were very low in all subjects. Here, IL27 is linked to chronic obstructive pulmonary disease.