Sputum CCL5 and CXCL11 levels were substantially higher in subjects with asthma than in subjects with COPD, with area under the ROC curves (ROC AUCs) of 0.74 (95% CI, 0.67-0.82; P < .0001) and 0.72 (95% CI, 0.64-0.80; P < .0001), respectively. Here, CXCL11 is linked to chronic obstructive pulmonary disease.