Elevated IL-4, IL-13, and IL-17 levels in COPD-BS show Th2 response, which increases blood eosinophil counts and activity and is a potential treatable trait.24 His heightened eosinophilic inflammation correlates with a better response to ICS therapy, potentially reducing exacerbations.9,25 The increase in IL-13 in COPD-BS is consistent with the results obtained by Golpe et al.,12 underscoring its role in allergic inflammation by modulating lymphocyte and myeloid cell responses. This evidence concerns the gene IL4 and chronic obstructive pulmonary disease.