CSF2 and chronic obstructive pulmonary disease: For instance, alveolar macrophages secrete tumor necrosis factor-α (TNFα) [6] and granulocyte macrophage-colony stimulating factor (GM-CSF) [7] upon stimulation with cigarette smoke and increased levels of these cytokines are measured in the bronchiolar alveolar lavage (BAL) fluid, sputum or peripheral blood of COPD patients [8-12].