For instance, a subset of COPD patients have elevated IL-5 levels in their blood and airways34,35 and there are two monoclonal Ab (mAb) drugs (i.e., Mepolizumab and Benralizumab) that target to IL-5 or IL-5 receptor alpha (IL-5Rα), respectively, that have been investigated for their ability to reduce exacerbation rate in COPD patients (NCT02105948, NCT01463644, NCT02105961 and NCT01227278). This evidence concerns the gene IL5RA and chronic obstructive pulmonary disease.