First, we observed upregulated protein levels of C-X-C Motif Chemokine Ligand 2 (CXCL2) and Granulocyte Colony-Stimulating Factor (G-CSF), which are recognized as neutrophil attractants, in the lung tissue of P + COPD group (Fig. 4a). Here, CXCL2 is linked to chronic obstructive pulmonary disease.