In all COPD patients, the sputum eosinophil percentage positively correlated with sputum ILC2s (r = 0.48; p = 0.002), IL-5+ILC2s (r = 0.50; p = 0.001), TSLPR+ILC2s (r = 0.55; p = 0.004), ST2+ILC2s (r = 0.47; p = 0.003) and IL-17RB+ILC2s (r = 0.40; p = 0.01) (Figure 5). Here, IL5 is linked to chronic obstructive pulmonary disease.