The content of CCR6 in BALF was significantly increased in the COPD group compared with controls (105.81 ± 1.58 ng/L vs 43.57 ± 3.18 ng/L; P < 0.001) and significantly decreased in the CCL20 monoclonal antibody treated group compared with the COPD group (79.84 ± 6.49 ng/L vs 105.81 ± 1.58 ng/L; P < 0.001) (Figure 6). This evidence concerns the gene CCR6 and chronic obstructive pulmonary disease.