IFNG and chronic obstructive pulmonary disease: Furthermore, we measured and compared different key cytokines for pulmonary health, such as interleukin (IL)-2, IL-6, IL-8, IL-10, granulocyte-macrophage colony-stimulating factor (GM-CSF), and interferon-γ (IFN-γ) in BCO patients, COPD patients, and healthy controls.