The upregulation of surface molecules for antigen recognition and presentation (such as CD1a, BDCA-1, Langerin, MMR, BDCA-4 and CD86) and the unchanged expression of BDCA-3 on BALF mDCs found in the current study in smokers with COPD is strikingly similar to the previously reported changes on BALF mDCs of smokers with normal spirometry [14]. Here, THBD is linked to chronic obstructive pulmonary disease.