IL5 and Increased total eosinophil count: Although sputum IL-5 levels are strongly associated with sputum eosinophilia (rs = 0.572, P < .0001) and sputum ECP levels (rs = 0.604, P < .0001, see Figs E6 and E11 in this article's Online Repository at www.jacionline.org), sputum IL-13 levels are not highly correlated with sputum IL-5 levels (P = .6) and, conversely, are suppressed in both patients with neutrophilic and those with eosinophilic asthma (see Fig E6, D), suggesting that IL-13 production, which is strongly associated with GINA treatment step, is more steroid responsive than IL-5.