Among serum mediators, elevated IL-17A and GM-CSF (granulocyte-macrophage colony-stimulating factor) were observed in the neutrophilic balanced subgroup, and IL-5 and eotaxin-3 were higher in the eosinophilic subgroup, both in COPDMAP and BEAT-COPD (Figure E14 and Table E2). Here, CCL26 is linked to chronic obstructive pulmonary disease.