TRAF2 and chronic obstructive pulmonary disease: TNF‐α can activate the TNF‐α/NF KB signalling pathway to induce the release of interleukin‐8 (IL‐8) by activating tumour necrosis factor receptor 1 (TNFR1) and recruiting tumour necrosis factor receptor–related factor 2 (TRAF2) in the COPD response.