TNF and chronic obstructive pulmonary disease: Several proinflammatory cytokines and chemokines, such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β, macrophage inflammatory protein (MIP)-2 and monocyte chemoattractant protein (MCP)-1, as well as certain growth factors such as macrophage colony-stimulating factor (M-CSF), are involved in COPD physiopathology and contribute to maintaining the inflammation [2].