The majority of CD66b+ exosomes (96.1%) in COPD BALF expressed NE, whereas few (1.3%) of those collected from healthy, nonsmoking (NS) control BALF expressed NE, suggesting that COPD BALF exosomes principally induce alveolar enlargement by NE present on the CD66b+ population of exosomes (whereas NS CD66b+ purified BALF exosomes did not). The gene discussed is CEACAM8; the disease is chronic obstructive pulmonary disease.