CCL20 and chronic obstructive pulmonary disease: PAA was significantly greater in COPD group than in the control group (76.64 ± 4.179 vs 39.63 ± 2.848; P < 0.001) and significantly smaller in the CCL20 monoclonal antibody treated group than in the COPD group (62.39 ± 3.422 vs 76.64 ± 4.179; P = 0.010).