Studies have shown that in the small airways and alveoli of COPD patients, the number of immature dendritic cells significantly increases, while the number of mature dendritic cells decreases, particularly in advanced COPD patients, where alveolar CD1a+langerin-, BDCA-2+CD11c+dendritic cell subpopulations significantly increase (135).These changes are closely associated with the immunopathology of COPD. Here, CD1A is linked to chronic obstructive pulmonary disease.