Notwithstanding the similarities, patients with COPD are generally less responsive to corticosteroids than asthmatics, which may partly result from the distinct difference in key inflammatory cells involved in COPD (neutrophils, macrophages, CD8 + lymphocytes)26 and asthma (eosinophils, CD4 + lymphocytes)27. This evidence concerns the gene CD8A and chronic obstructive pulmonary disease.