Our main results are as follows: 1) the number of all DCs subtypes measured by flow cytometry did not differ significantly between COPD patients and non-COPD subjects; 2) current smokers had a reduced number of DCs (especially BDCA3-positive mDCs2); 3) the correlations between different subtypes of DCs varied according to the study subgroups; and 4) current smoking was associated with a reduced expression of maturation markers in DCs. The gene discussed is THBD; the disease is chronic obstructive pulmonary disease.